IS Hand / LE 2018

A 1-year-old boy is brought to the office by his parents for evaluation and correction of the findings shown in the photograph (no webspace). The patient is otherwise healthy. Which of the following techniques is most appropriate to reconstruct the apex of the web space in this patient? A. Bilobed flap from the dorsal hand B. Cross-finger flap C. Full-thickness skin grafting D. Proximally based dorsal rectangular flap E. Split-thickness skin grafting

D. Full-thickness skin grafts are usually used to close the resultant defects of the fingers after release of congenital syndactyly. Several local dorsal flaps have been described to reconstruct the web space with differing shapes to avoid the use of skin grafts, including rectangular, a V-Y island, a dorsal flap interdigitated with a small palmar V and a dorsal V-shape. A bilobed flap has been described for treating web creep in adults, but would not routinely be used.

A 30-year-old woman comes to the office because of pain and swelling of the right radial/distal forearm. The pain worsens with ulnar deviation of the wrist over a clasped thumb. Immobilization and a corticosteroid injection have failed, and surgical release is planned. Which of the following anatomic findings is most likely to have contributed to this patient's condition? A. Absent extensor pollicis brevis B. Combined first and second compartments C. Distal muscle belly on extensor pollicis brevis tendon D. Multiple slips of abductor pollicis longus E. Septum between abductor pollicis longus and extensor pollicis brevis

E. DeQuervains is tendonitis of first compartment (EPB / APL). There is considerable variability in the anatomy of the first dorsal compartment of the wrist; this is particularly true when considering the presence or absence of a septum in the compartment. The significance of these variations is that they may predict failure of steroid injections to resolve de Quervain disease and must be considered when releasing the compartment surgically to ensure that a complete release of all tendons is performed. While studies vary, based on methodology of imaging, cadaveric dissection, or surgical findings, there is consistency that septa are more common in patients presenting with de Quervain disease than in the general population. Studies have shown no association between the number of APL slips and de Quervain disease.

A 60-year-old man sustains a Gustilo type IIIB open fracture of the distal left tibia during a boating accident. There is severe contamination of the wound, and the patient undergoes multiple formal washouts in the operating room. There is no neurovascular compromise of the extremity. He undergoes external fixation to stabilize the limb. Which of the following is the most appropriate next step in treatment? A. Coverage with a free tissue transfer B. Negative pressure wound therapy until secondary healing is achieved C. Pedicled gastrocnemius muscle and skin grafting D. Primary bone allografting E. Split-thickness skin grafting

A. Gustilo classification: Type I: The wound is less than 1 cm long. There is little soft-tissue damage and no sign of crush injury. There is no or minimal comminution of the fracture. Type II: The laceration is more than 1 cm long but there is no extensive soft tissue damage, flap, or avulsion. There is slight to moderate crushing injury, moderate comminution of the fracture. Type III: Extensive damage to the soft tissues, including muscle, skin, and neurovascular structures, and a high degree of contamination. Type IIIA: Soft tissue coverage of the bone is adequate. Type IIIB: Extensive injury to or loss of soft tissue, with periosteal stripping and exposure of bone, massive contamination, and severe comminution of the fracture from high-velocity trauma Type IIIC: Any open fracture with a vascular injury requiring repair. Free tissue transfer will bring healthy, nontraumatized tissue into the area to cover the exposed broken bone. Multiple recent studies have shown equivalence of muscle versus skin/fat/fascia flaps for coverage of the open fracture even in patients with osteomyelitis. Negative pressure wound therapy has proven to be an excellent adjunct in the management of patients with these injuries. Between washouts, negative pressure devices can help decrease edema and isolate the wound and bone from the outside world. In a patient with a IIIB injury, there is insufficient tissue available to cover the wound. Therefore, secondary intention would not close the wound. Split-thickness skin grafting provides an epithelial barrier to help seal off a wound from outside contamination. Grafts require a viable wound bed to survive. There must be a pliable bed to help grafts resist minor trauma in the future. With the periosteal stripping in this type of injury, a graft would not survive. In addition, graft placed directly on bone with periosteum would be very vulnerable to breakdown from minor trauma. Bone allografting can be used to bridge defects in many circumstances. In the patient described, the severe contamination of the initial injury would make bone allografting much less appealing than autografting. Because of contamination, any type of bone grafting may need to be delayed until after achieving stable soft tissue coverage of the fracture. A pedicled gastrocnemius muscle flap provides excellent coverage for defects about the knee, including the proximal tibia. Although the free gastrocnemius muscle flap could be transferred to any location, the pedicled flap would not be able to reach the distal tibia.

A 64-year-old woman with rheumatoid arthritis is evaluated for abrupt onset of inability to extend the ring and little fingers of the left hand. Surgical exploration confirms attritional tendon rupture and caput ulnae syndrome. In addition to tendon reconstruction, which of the following interventions is most likely to prevent recurrence of this condition? A. Distal ulna resection B. Proximal row carpectomy C. Radiocarpal arthrodesis D. Scaphoid excision and four-corner fusion E. Trapeziectomy and ligament reconstruction

A. Darrach procedure, or distal ulna resection, is a well-established procedure to treat distal radioulnar joint (DRUJ) arthritis and distal ulnar instability such as in caput ulnae syndrome. A dorsal approach is used to gain access to the DRUJ via dorsal fifth extensor compartment approach. The triangular fibrocartilage complex (TFCC) and extensor carpi ulnaris (ECU) sheath are preserved. Excision of the distal ulnar head is performed proximal to the radial sigmoid notch. DRUJ arthritis and instability may result in attritional rupture of the extensor tendons due to tendons abrading against the dislocated, eroded ulna head as well as restriction of forearm rotation. Thus, the aims of treatment for DRUJ arthritis are pain relief, prevention of attritional tendon rupture if the patient presents prior to tendon rupture, and improvement of forearm rotation. These aims are commonly achieved using a Darrach procedure or Sauvé-Kapandji procedure and less commonly by ulnar head replacement arthroplasty. The Sauvé-Kapandji procedure was introduced amid concerns over ulnar translocation of the carpus following resection of the distal ulnar head as done in the Darrach procedure, yet both procedures have shown good outcomes in the treatment of DRUJ arthritis. In fact, a recent systematic review found no significant difference in outcomes between the two procedures in rheumatoid arthritis patients. Proximal row carpectomy and scaphoid resection and four-corner fusion are both used to treat wrist arthritis, but are usually for osteoarthritis such as with SLAC and scaphoid nonunion advanced collapse (SNAC) wrist, and are not generally used in rheumatoid arthritis patients. Trapeziectomy and ligament reconstruction are procedures used to treat carpometacarpal arthritis of the thumb, not DRUJ arthritis. Radiocarpal arthrodesis is a treatment for radiocarpal arthritis, and not DRUJ arthritis with caput ulnae.

Which of the following Zone II four-strand flexor tendon repair configurations demonstrates the greatest overall fatigue strength and gap resistance in biomechanical testing? A. 3-0, Dorsal placement, Locking B. 4-0, Volar placement, Grasping C. 3-0, Volar placement, Locking D. 4-0, Dorsal placement, Locking E. 3-0, Dorsal placement, Grasping

A. Increasing the suture caliber has shown to increase the force in static testing and fatigue strength in dynamic testing. The use of 3-0 polyethylene terephthlate fiber suture increased the fatigue strength compared with 4-0 sutures by two to three times. The placement of the suture dorsally has been shown to increase the strength of the repair by two to four times, and is more environmentally favored because of a decreased risk for interference with the synovial fluid. It has been shown that locking loops improve force and gap resistance compared with grasping loops in flexor tendon repair. Statistically significant improvement was observed with the locking loop technique for ultimate and gap strength values using 2-0 core suture and ultimate strength values using 3-0 core suture.

In patients with basilar joint arthritis of the thumb, treatment with trapeziectomy alone compared with trapeziectomy with ligament reconstruction and tendon interposition is most likely to result in which of the following? A. Decreased complication rate B. Increased risk for recurrent pain C. Longer recovery time D. Worse functional outcomes

A. Simple trapeziectomy was first described in 1947 and though it is only utilized by a small minority of hand surgeons in the United States as solitary treatment for basilar thumb arthritis, its efficacy has not been demonstrated to be inferior to the more commonly employed trapeziectomy with ligament reconstruction and tendon interposition. Meta-analysis has demonstrated that simple trapeziectomy is equally beneficial in terms of pain relief and function as trapeziectomy with ligament reconstruction and tendon interposition, but results in fewer complications. A variety of reconstructive techniques have been employed in management of basilar thumb arthritis. Most commonly employed in the United States is the trapeziectomy with ligament reconstruction and tendon interposition utilizing the flexor carpi radialis tendon. Other described techniques include CMC joint implant arthroplasty, partial trapeziectomy with interposition arthroplasty, and thumb metacarpal extension osteotomy for early-stage arthritis. None of these techniques have demonstrated superiority over simple trapeziectomy, and synthetic implants have been associated with significant complications.

A 47-year-old man is brought to the emergency department after sustaining a stab wound injury to the left shoulder. Physical examination shows isolated loss of deltoid function. The injured nerve is supplied by which of the following nerve roots? A. C5 through C6 B. C6 through C7 C. C7 only D. C7 through T1 E. T1 only

A. The deltoid muscle receives motor innervation from the axillary nerve. The axillary nerve receives its contributions from C5 and C6 roots. These roots come together to form the superior trunk, which splits into anterior and posterior divisions. The axons heading to the axillary nerve travel in the posterior division, which joins the other posterior divisions from middle and inferior trunks to form the posterior cord. The axillary nerve arises from the posterior cord and travels laterally to innervate the deltoid muscle. C7 is the primary innervation to the latissimus dorsi and triceps, and contributes to digital extension as well. C8 and T1 primarily serve the hand, providing intrinsic muscle innervation.

A patient with severe traumatic brachial plexus root avulsion injury is scheduled to undergo functioning free muscle transfer for simultaneous restoration of both elbow flexion and finger flexion, in addition to other reconstructive procedures. Use of which of the following muscles is most appropriate for this purpose? A. Gracilis B. Pectoralis major C. Rectus abdominus D. Serratus anterior E. Trapezius

A. The gracilis muscle is the most commonly described muscle for use as a free functioning muscle in reconstruction of upper extremity function following brachial plexus injury. Common options for use in these reconstructions include the gracilis, latissimus dorsi, rectus femoris, and vastus lateralis. The gracilis muscle has good excursion, size, and length, but does lack strength compared with some other muscle options. The rectus abdominis, serratus anterior, and trapezius muscles have not been described for free functioning muscle transfer in the upper extremity. Though the pectoralis major muscle was described as a free functioning muscle transfer by Manktelow and McKee in 1978, it has not been a commonly used muscle.

A 25-year-old man sustained traumatic amputation of the nondominant index finger 3 hours ago and requests replantation. Which of the following factors has the greatest influence on survival of the injured digit after replantation? A. Mechanism of injury B. Number of vessels repaired C. Patient's smoking status D. Time from injury to replantation E. Use of anticoagulation

A. The mechanism of injury has the greatest influence on survival of replanted digits. Injuries from sharp devices that leave a clean cut with little or no crush component are the most amenable to replantation. The more the tissue is crushed or avulsed, resulting in greater vessel injury, the less likely the digit will survive. No studies have shown that the use of anticoagulants changes survival rates. Smoking decreases blood flow in digits, but has not been widely studied in replantation. Fingers have no muscle, which is the tissue most susceptible to ischemia, so digits can tolerate long delays as long as they are treated correctly. At least two veins per artery have been shown to help prevent venous congestion.

A 46-year-old woman comes to the office for initial evaluation and management of the right upper extremity because of swelling and discomfort. Medical history includes right modified radical mastectomy for T3 N2 breast cancer 2 years ago. The patient reports that the swelling started 9 months after her procedure, and that she has had two episodes of cellulitis of the right upper extremity that required treatment with oral antibiotics. Physical examination shows marked non-pitting edema of the right upper extremity and a well-healed surgical incision along the right chest wall. There is currently no evidence of recurrent breast cancer. BMI is 27 kg/m2. Which of the following is the most appropriate initial management for this patient? A. Complete decongestive therapy B. Magnetic resonance lymphangiography C. Pentoxifylline therapy D. Vascularized lymph node transfer E. Weight loss

A. This patient has post-mastectomy lymphedema. Incidence of lymphedema after axillary node dissection has been reported to be up to 14%. It very often presents after a period of latency after surgical intervention. The mainstay of initial treatment for this condition is complete decongestive therapy (CDT). CDT is a therapist-driven modality that incorporates a multimodality approach including manual lymphatic drainage, daily bandaging, exercise, and skin care. After a period of initial intensive therapy, patients are transitioned to self-directed care under the supervision of a therapist with compression garments and adjunctive modalities. The relative value and benefit of each of the components of CDT are the source of active investigation. Initial management of lymphedema with some form of compression and therapy is the currently accepted approach. Significant advances have been made in understanding the pathophysiology of lymphedema. There is a complex interplay between the lymphatic, venous, and interstitial systems with venous insufficiency and obesity contributing to the incidence and severity of lymphedema. These conditions should be investigated and treated in conjunction with CDT. The patient in this question is not obese and weight loss would not be an initial appropriate step in management of her lymphedema. Various pharmacotherapies have been investigated in the treatment of lymphedema. These include diuretics, coumarin, vitamin E, pentoxifylline, and nonsteroidal anti-inflammatory drugs (NSAIDs). None have been demonstrated to provide efficacy in the treatment of lymphedema. In patients who have persistent infections or symptomatic lymphedema after conservative management, there may be a role for treatment with physiologic surgical therapies such as vascularized lymph node transfer or lymphaticovenular anastomosis. Imaging modalities such as magnetic resonance lymphangiography may provide high-resolution visualization of the lymphatic system and assist in procedure selection, but should not be employed as a portion of the initial treatment of a patient with lymphedema.

A 54-year-old woman is evaluated for an injury to the proximal interphalangeal (PIP) joint of the long finger of the left hand that she sustained during a motor vehicle collision. X-ray study is shown (pilon fracture of base of middle phalanx). Which of the following methods is the most appropriate surgical management of this patient's fracture? A. Dynamic external fixation B. Hemihamate arthroplasty C. Lag screw fixation D. PIP joint arthrodesis E. Volar plate arthroplasty

A. This patient presents with an intra-articular, or pilon, fracture of the middle phalanx base. Typically, pilon fractures are axial load injuries to the finger resulting in impaction, comminution, central depression, and splaying of the middle phalanx fracture fragments both volarly and dorsally. Fractures involving the proximal interphalangeal (PIP) joint are generally divided into three categories: volar rim fractures, dorsal rim fractures, and pilon fractures (volar and dorsal rim) with or without joint dislocation. Joint dislocation occurs secondary to ligamentous injury and correlates to the amount of articular surface involved in the fracture. Management of these injuries depends on the fracture type, severity, degree of articular surface involvement, extent of dislocation, and associated soft-tissue injuries. Pilon fractures due to the comminution and crush component of the middle phalanx base can be very difficult to treat. Post-traumatic osteoarthritis causing stiffness, impaired function, and pain is a known complication. Multiple different types of dynamic external fixation devices have been described in the literature. These are mostly fabricated from K-wires with or without a rubber band traction system. The devices work by the principles of a lever and ligamentotaxis to maintain fracture reduction and joint congruency and to allow early motion for joint surface remodeling. The devices are inexpensive and relatively easy to place with experience, and can be placed using local anesthesia. Dynamic distraction external fixation has been indicated for use in pilon fractures and unstable PIP joint fracture dislocations. The constructs are usually removed 4 to 6 weeks after fracture consolidation and clinical healing is present. Most studies report 60 to 88 degrees of PIP motion with good patient satisfaction and return of function. The presence of arthritic changes on x-ray studies is common after these injuries. Pin tract infections up to 40% have been reported in retrospective studies; however, these seem to be treated with oral antibiotics alone and do not require pin removal. They do not progress to osteomyelitis. PIP joint arthrodesis is an option for treatment in very severe pilon fractures or crush injuries with severe soft-tissue involvement; however, this sacrifices motion and should be reserved for cases where there are no other viable treatment options. Hemi-hamate arthroplasty and volar plate arthroplasty are operations described to treat PIP joint fracture dislocations with isolated volar rim involvement. These procedures require an intact dorsal cortex of the middle phalanx base to achieve stable fixation. Both procedures are indicated for comminuted fractures involving 30 to 50% of the articular surface of the middle phalanx base. Open reduction and internal fixation of pilon fracture with locking plates has been described, but is technically challenging and requires significant soft-tissue dissection compared with percutaneous dynamic external fixation. Lag screws are inadequate fixation in general for pilon fractures. Isolated volar rim fractures with a larger fracture fragment can be treated successfully with lag screws.

A 58-year-old man is to undergo excision of a painful ulnar artery aneurysm of the palm, which has been causing ulnar nerve compression. Preoperative examination shows a digital/brachial index (DBI) of 0.5 in the small finger. After excision of the diseased segment, which of the following is the most appropriate next step in management? A. Arterial reconstruction B. Botulinum toxin type A injection C. Extended periarterial sympathectomy D. Periarterial injection of 2% lidocaine E. Postoperative anticoagulation

A. Ulnar artery aneurysms may cause symptoms because of local mass effect, distal embolization, and/or episodic vasospasm. Ligation of the ulnar artery to exclude the aneurysm from hand circulation can effectively eliminate risk for embolism, but may rob the digits of necessary blood flow if there is not enough collateral circulation from the deep arch or other sources. Measuring the digital-brachial index (DBI) is an effective way to assess whether or not there is sufficient blood flow to the digits. A normal DBI is between 0.75 and 0.97. Values equal to or less than 0.7 indicate inadequate perfusion. Below a DBI of 0.5, tissue loss is inevitable. Following ulnar artery ligation, if the DBI is below 0.7, then reconstruction of the ulnar artery is recommended rather than simple aneurysm excision or ligation. This is typically accomplished with a reversed vein graft or an arterial graft (e.g., from the lateral femoral circumflex system). Anticoagulation alone, or anti-vasospastic drugs, such as botulinum toxin type A or lidocaine, are not sufficient in this clinical situation, where blood flow is limited because of blockage of flow. While sympathectomy could improve circulation in cases of vasospasm, this patient had no history

A 20-year-old rugby player is evaluated for an acute thumb injury 4 hours after falling onto his outstretched hand while being tackled. X-ray study is shown (bennet fracture). Surgical intervention is planned. Which of the following is the most appropriate force to apply to the thumb metacarpal during reduction? A. Abduction B. Axial compression C. Flexion D. Supination

A/ In a Bennett fracture, the smaller volar-ulnar fragment is retained by the anterior oblique (beak) ligament, while the abductor pollicis longus, thumb extensor tendons, and the adductor pollicis combine to distract the base of the larger shaft fragment radially, dorsally, and proximally. These distracting forces create joint incongruity, which is a relative indication for fracture reduction. These forces must be countered to reduce the fracture, thus, requiring axial distraction, pronation, and abduction of the metacarpal shaft, while simultaneously applying external pressure at the radial base of the metacarpal. Axial compression will worsen proximal migration of the metacarpal shaft. Extension will worsen dorsal displacement, and supination will further distract the volar surfaces of the fracture fragments. Application of these forces will not promote fracture reduction.

A 30-year-old man is scheduled to undergo transhumeral amputation after unsalvageable brachial artery occlusion. A photograph is shown. Use of targeted muscle reinnervation may allow improved functional recovery by which of the following means? A. Better bulk and durability by preventing denervation atrophy of muscles at the amputation stump B. Better prosthesis control by input from median and ulnar nerve signals C. Better sensory detection in the prosthesis by positioning amputated nerve stumps closer to the skin closure D. More precise control of an osseointegrated body-powered prosthesis E. Preservation of greater bony length in the amputation stump

B. A body-powered prosthesis uses motion of remaining joints, such as the gleno-humeral and scapulo-thoracic joints, to control an upper extremity prosthesis. Targeted muscle reinnervation (TMR) would not affect function of a body-powered prosthesis. TMR positions amputated nerve stumps well within the remaining muscle and far from the cutaneous closure. Current prosthetics are not yet able to detect sensation and transmit this to the patient. Having nerve stumps near the amputation closure site increases the risk for neuroma pain. TMR has not been shown to decrease denervation atrophy of residual upper extremity muscles. TMR has gained increasing acceptance in the treatment of patients who have undergone or will undergo upper extremity amputation. Resected nerves, such as the median and ulnar nerves, can be coapted to nerve branches to remaining muscles, such as the pectoralis and deltoid. Transcutaneous EMG detectors are positioned over these reinnervation sites to detect nerve signal, which a myoelectric prosthesis can then use to better control distal joints. TMR does not affect the amount of bony length that can be preserved in an amputation

A 24-year-old man comes to the office because of a brachial plexus injury sustained in a motorcycle accident. Nerve transfer to the biceps for restoration of elbow flexion is planned. Which of the following fascicles or nerves is the most appropriate donor for the transfer? A. Distal spinal accessory nerve B. Flexor carpi ulnaris fascicle of the ulnar nerve C. Medial pectoral nerve D. Palmaris longus fascicle of the median nerve E. Thoracodorsal nerve

B. Adult upper trunk brachial plexus injuries result in significant disability. Several surgical treatment strategies exist, including nerve grafting, nerve transfers, and a combination of both approaches. The flexor carpi ulnaris (FCU) fascicle of the ulnar nerve to biceps transfer was first described by Oberlin et al in 1994. Generally, the donor nerve with the largest caliber and the greatest number of motor axons should be used for elbow flexion. The other suggested nerve transfer options are also possibilities, but are not as preferable as the FCU fascicle transfer. MacKinnon has advocated transfer of the FCU fascicle of the ulnar nerve to the biceps and FCR fascicle of the median nerve to the brachialis to maximize recovery of elbow flexion.

A neonate is born with unilateral edema of the arm. During the ensuing day, there is worsening edema and bullae formation. Which of the following is the most appropriate next step in management of this patient? A. Administration of intravenous antibiotics and elevation of the arm B. Compartment release C. Continued observation and dressing change D. Debridement and skin grafting E. Treatment in a hyperbaric chamber

B. Compartment release should be performed early and urgently. The other treatments above may play a role in secondary treatment. Volkmann's ischemia is not rare and awareness of the diagnosis is important. The sentinel lesion of neonatal compartment syndrome is bullous formation on the dorsum of the hand or arm. Etiology is often in utero and can be amniotic bands, umbilical cord loops, forceps extraction, oligohydramnios, preeclampsia, and excessive maternal weight. Diastolic pressures in neonates are usually 40 mmHg or less. Small increases in compartment pressure are therefore not tolerated well. The six P's of compartment syndrome, which include pain, paresthesias, pulselessness, pallor, paralysis, and pressure, will not be seen in the neonate. The three A's, which precede the six P's in children, are agitation, anxiety, and increasing analgesic requirements; and will not be seen in the neonate.

A 20-year-old woman comes to the office for evaluation of chronic pain of the right wrist, which is alleviated by nonsteroidal anti-inflammatory drugs (NSAIDs). Osteoid osteoma is suspected on x-ray. Which of the following imaging studies is most likely to confirm the suspected diagnosis? A. Bone scan B. CT scan C. Laser fluorescence angiography D. Magnetic resonance arthrography E. Ultrasonography

B. Osteoid osteoma is a benign bone tumor that arises from osteoblasts; the principal symptom is focal pain at the site of the lesion. Multiple studies suggest that CT is the best imaging technique for detection of this tumor. Specifically, CT is best at depicting the nidus, the radiolucent area typical of this tumor type. Within the radiolucent nidus, a central area of high attenuation is often seen, representing mineralized osteoid. As ultrasound waves do not adequately penetrate bone, this intracortical lesion would not easily be detected by this technique. Although magnetic resonance (MR) has been used to detect these lesions, it is not as sensitive at detecting the nidus as CT scanning. This is because the nidus, especially if it is small, will have signal similar to cortical bone on MR. Although an arthrogram may detect an intra-articular osteoid osteoma, this is a more unusual entity. A bone scan may show the lesion, but it is nonspecific and will not confirm the diagnosis. Laser fluorescence angiography has gained popularity for assessing the perfusion of soft tissues (skin, flaps, etc.), but this technique will not help assess bone or tissues of significant depth, nor can it reliably distinguish tumor from other tissue.

A 50-year-old man comes for evaluation 8 weeks after dislocating the right knee when he tripped on a railroad tie at work. Physical examination shows a right footdrop and dysesthesia along the lateral lower leg and dorsolateral foot. Electromyography and nerve conduction studies are most likely to confirm injury to which of the following nerves? A. Femoral B. Peroneal C. Plantar D. Sural E. Tibial

B. The peroneal nerve innervates the tibialis anterior and extrinsic extensors of the toes, thereby extending the ankle. Paralysis of these muscles leads to footdrop. The sural nerve is a cutaneous nerve about the lateral ankle. The tibial nerve innervates the ankle and toe flexors, and paralysis of this nerve would not lead to a footdrop. The femoral nerve runs in the anterior thigh and is not likely to be affected by a knee dislocation; it innervates the extensors of the leg at the knee. The plantar nerves are the terminal branches of the tibial nerve and provide intrinsic innervation to the foot and sensation to the medial and lateral plantar foot.

A 22-year-old man comes to the emergency department after sustaining a laceration to the dorsal thumb by punching a glass door. Radial nerve block is planned during surgical repair. Which of the following is the approximate distance proximal to the radial styloid in which the superficial branch of the radial nerve pierces the deep fascia? A. 0 to 4 cm B. 5 to 9 cm C. 10 to 14 cm D. 15 to 19 cm

B. The superficial branch of the radial nerve runs below the brachioradialis muscle in the mid-forearm, later becoming sub-fascial between the brachioradialis and extensor carpi radialis longus (ECRL) muscles. Approximately 8 to 9 cm proximal to the radial styloid, the superficial branch of the radial nerve (SBRN) becomes subcutaneous, piercing the fascia. The ideal location of infiltration for a radial nerve block is at the sub-fascial location just before the nerve becomes subcutaneous.

A 23-year-old woodworker sustains an injury to the dominant left thumb that involves the loss of less than 2 cm of the distal pulp with exposed bone from a planing machine. Which of the following reconstruction methods is most likely to provide normal sensation to the volar pulp of this patient's thumb? A. Cross-finger flap from the long finger B. Islandized Moberg flap C. Flag flap D. Thenar flap E. Venous flow-through flap

B. The venous flow-through flap was described for small defects of the dorsum of a digit or hand where end-to-end anastomoses of the included veins on the proximal and distal edges of the flap can provide venous outflow for the digit and supply the flap. A defect from the distal, volar surface of the thumb would not have any veins large enough to use. A cross-finger flap is a classical solution to cover the volar aspect of a digit. The other mentioned flaps are also excellent options for volar thumb coverage, except for the thenar flap. The thenar flap is used for distal pulp defects of the fingers in children. The only flap that maintains the normal sensation of the thumb pulp is the Moberg flap, which advances the volar aspect of the thumb on its neurovascular pedicles. The islandized (O'Brien) modification was to make a transverse incision at the base of the thumb and dissect the neurovascular bundles to allow the flap to travel further distally, and then placing a skin graft over the proximal defect.

A 27-year-old man is brought to emergency department because of a thumb avulsion injury measuring 3 × 3 cm. A photograph is shown. Which of the following is the best option for sensate, soft-tissue coverage? A. Cross-finger flap B. First dorsal metacarpal artery flap C. Moberg flap D. Pedicled groin flap E. Skin grafting

B. There are several sensate options for thumb pulp deformities. These include neurovascular island flaps, Moberg flaps, free toe pulp flaps, and the first dorsal metacarpal artery flap (FDMA). Cross finger flaps, skin grafts, and pedicle groin flaps do not have innate innervation. The defect in the question involves the entire pulp of the thumb overlying the distal phalanx and is too large for a Moberg advancement flap. The FDMA flap is supplied by its eponymous artery, which travels in the fascia overlying the index metacarpal and supplies the skin overlying the dorsum of the proximal phalanx. The vessel is accompanied superficially by a branch of the radial nerve that provides neural activation to the skin overlying the proximal phalanx of the index finger. The flap can be transposed to provide sensate coverage of the tip of the thumb, and can provide sufficient size to resurface relatively large defects. Cortical reorientation is the fact that the brain recognizes a stimulus from the flap area as a stimulus from the thumb, and not from the index finger. This process takes some time, but is usually complete after 2 years. Average static two-point discrimination in these flaps utilized for thumb resurfacing is 10 to 11 mm. Use of the FDMA flap for resurfacing of the thumb pulp has been compared to heterodigital island flaps in several studies. Both remain options to be considered, but the ease of elevation, limited dissection, and acceptable donor site morbidity make the FDMA flap a common primary option for thumb tip resurfacing.

A 40-year-old man comes to the physician because of a 3-month history of pain and swelling over the proximal phalanx of the right index finger. He has no history of trauma. X-ray studies and MRI of the finger show an expansile osteolytic lesion of the proximal phalanx. Examination of a specimen obtained on biopsy confirms the diagnosis of giant cell tumor of the bone. Which of the following is the most appropriate staging test for this patient? A. CT scan of the cervical spine B. CT scan of the chest C. MR arthrography of the wrist D. MRI of the brain E. Pulmonary function testing

B. This patient is presenting with a primary giant cell tumor of the proximal phalanx bone. Giant cell tumors of the bone are considered benign but locally aggressive tumors. Only 2 to 5% of giant cell tumors arise from the bones of the hand. These lesions have a 1 to 5% incidence of pulmonary metastases. The distal radius is the third most common site of giant cell bone tumor origin. Hand and distal radius tumors have higher rates of recurrence and metastasis. The lungs are the most common site of metastatic lesions and a CT scan of the chest is recommended as part of the diagnostic work-up. The tumors are graded radiographically according to the Campanacci grading system. Grade I lesions are well-demarcated with an intact bony cortex. Grade II lesions show cortical expansion, and Grade III lesions show cortical destruction with soft-tissue extension. Grade I and II lesions can be treated with curettage and bone grafting. Adjuvant treatments such as phenol and liquid nitrogen have been recommended, but their efficacy has not been proven. Recurrence rates have been reported between 30 and 80% with this approach. Later stage tumors are treated with en bloc excision or amputation and reconstruction with vascularized or nonvascularized bone grafts. High rates of tumor recurrence are thought to be due to incomplete resection or late presentation at the time of diagnosis. There is no specific added benefit for an arthrogram of the wrist in a tumor arising from the proximal phalanx as in this case. MR arthrography of the wrist, CT scan of the cervical spine, MRI of the brain, and pulmonary function testing are not typically used for staging giant cell tumor of the bone.

A 53-year-old man comes to the emergency department because of an avulsion degloving injury to the left nondominant thumb sustained 3 hours ago. The amputated part is not retrievable. Physical examination shows loss of skin from the interphalangeal joint distally on both volar and dorsal surfaces. The distal phalanx and flexor pollicis longus and extensor pollicis longus tendons are intact. He has no other associated injuries. Which of the following is the most appropriate method of reconstruction of the thumb? A. Amputation revision at the mid-proximal phalanx B. Great toe wraparound flap C. Radial forearm osteocutaneous flap D. Second toe-to-thumb transfer E. Volar neurovascular advancement flap

B. Thumb reconstruction remains a difficult challenge for hand surgeons. Amputations of the skin distally may be covered with palmar advancement flaps; however, this technique is only limited to wounds less than 50% of the palmar surface of the thumb distal to the interphalangeal joint. In order to preserve length and function in more proximal amputations, either a regional or distant flap is required. The toe-to-thumb wraparound flap requires a microvascular anastomosis of digital vessels and nerves, providing excellent sensation and cosmetic results. The toe donor site can be covered with a skin graft in order to preserve length. The volar neurovascular advancement flap would not adequately cover a defect this size. Amputation at the mid-proximal phalanx would result in a very short thumb with loss of function. The radial forearm flap may be utilized to cover the above defect; however, it would lack adequate sensation. Any osteocutaneous radial forearm flap would not be indicated since there is preservation of the bone. Similarly, a second toe-to-thumb transfer would not be indicated since there is preservation of bone in this patient.

Which of the following is the type of axon fiber (neuron) that is primarily involved with the autonomic changes that occur with complex regional pain syndrome (CRPS) type 1? A. A delta sensory B. Alpha motor C. C sensory D. Gamma motor E. Ia sensory

C. C sensory fibers are responsible for a deeper, more non-localizable pain. C fibers can react to various stimuli, including thermal, mechanical, or chemical. C fibers respond to physiologic changes in the body, such as hypoxia, hypoglycemia, hypo-osmolarity, the presence of muscle metabolic products, and light or sensitive touch. Paul Sudeck noticed that CRPS demonstrates classic inflammatory signs such as pain, swelling, erythema, hyperthermia, and impaired function. However, clinical chemistry markers of inflammation are not elevated. These findings imply a neurogenic inflammation. C fibers have an afferent function in the mediation of pain (and itch), but also an efferent neurosecretory function. They release neuropeptides such as substance P and calcitonin-gene-related peptide (CGRP). The presence of these neuropeptides might explain trophic and autonomic symptoms such as swelling, erythema, and hyperhidrosis. Elevated CGRP levels are also associated with autonomic disturbances, mainly with hyperhidrosis. Also, a role for CGRP in hair growth is suggested, and substance P seems to be involved in the regulation of osteoclastic activity. Alpha motoneurons innervate muscle fibers of skeletal muscle and are directly responsible for initiating their contraction. When the central nervous system sends out signals to alpha neurons to fire, signals are also sent to gamma motoneurons to do the same. This process maintains the tautness of muscle spindles and is called alpha gamma co-activation. Without gamma motoneurons, muscle spindles would be very loose as the muscle contracts. Unrestricted alpha activity would not allow for muscle spindles to detect a precise amount of stretch and would not allow for optimization of muscle function. Ia sensory fibers are a type of proprioceptor that is found inside the muscle itself. They lie parallel to the contractile fibers, and give them the ability to precisely monitor muscle length. A delta fiber is a type of sensory nerve fiber. A delta fibers carry cold, pressure and some pain signals. Because A delta fibers have a higher conduction velocity, and are responsible for quick, shallow pain to a specific area. They are activated by a stimulus of weaker intensity, and are not responsible for the autonomic changes seen with CRPS.

A 2-year-old boy is treated for congenital constriction band of the left upper extremity with distal edema. The child undergoes excision of 50% of the circumferential constriction band with direct closure. This intervention is most likely to have which of the following effects on the edema of the distal limb? A. Gradual improvement during childhood development B. Gradual worsening during childhood development C. Significant improvement within a few weeks of surgery D. Significant worsening during childhood development E. No effect

C. Congenital constriction band syndrome is a sporadic condition with an incidence varying from 1:1200 to 1:15,000 live births. There is a significant predilection for the upper extremities and distal limbs. The two main objectives for the treatment of congenital constriction band syndrome are improvement of function and improvement of cosmetic appearance. Different surgical techniques, such as Z-plasty, have been described and used for decades; however, direct closure after the excision of the constricting band is a simple yet effective treatment. With complete circumferential constriction bands, it is recommended that a two-stage correction approach be used. At the first operation, one-half of the circumference is excised; the other half can be excised after 3 to 6 months. This will avoid any problems to the distal circulation in the limb, which may already be compromised. Edema, when present, will significantly improve within a few weeks of the first surgery.

A 54-year-old man comes to the office because of an injury to the long finger of the dominant right hand sustained when it was pinched in a machine at work. Physical examination shows a 1.3-cm loss of pulp tissue with no exposed bone. To preserve function and sensation in the digit, which of the following is the most appropriate intervention? A. Amputation at the distal interphalangeal joint B. Cross-finger flap C. Moist dressings D. Thenar flap E. Volar V-to-Y advancement flap

C. Fingertip injuries are one of the most common problems encountered in hand surgery. The long finger is the most common finger involved. The patient's age, occupation, and compliance with treatment should be considered when determining treatment. When possible, if the patient has no exposed bone or only a small area of exposed bone, treatment with dressing changes offers excellent results. There is no donor site morbidity, scarring is often minimal, and return of sensation is generally excellent. Patients, however, need to be cautioned that a prolonged period of dressing changes is required, often lasting 3 to 6 weeks. Amputation at the distal interphalangeal joint would result in loss of function of the profundus tendon and grip weakness. Neurovascular island flaps and V-to-Y advancement flaps offer excellent closure options when digital length needs to be preserved and there is significant exposure of bone. However, with these flaps there is a donor defect and decreased sensation. Care must be taken when using a cross-finger flap or thenar flap in older patients to avoid contractures and stiffness of the digits.

A 45-year-old woman with systemic sclerosis (scleroderma) has severe Raynaud phenomenon. A photograph is shown. Periarterial injection of botulinum toxin type A is being considered for treatment in this patient. This treatment is believed to relieve vasospasm in Raynaud phenomenon by which of the following mechanisms? A. Blocking fast sodium channels in axonal gap junctions B. Increasing the activity of chronically down-regulated group C nerve fiber nociceptors C. Inhibiting Rho/Rho kinase activity D. Obstructing myofibroblast contractile activity in vascular smooth muscle E. Promoting substance P secretion/receptor sensitivity

C. Inhibit rho/rho kinase, substance P, and c-fiber nociceptors Several mechanisms have been proposed to explain the effect of botulinum toxin type A (Botox) to inhibit Raynaud phenomenon in patients with scleroderma. Studies have demonstrated inhibition of Rho/Rho kinase activity, inhibition of substance P secretion and receptor sensitivity, and decreasing the activity of chronically up-regulated C-fiber nociceptors all to occur in models of Raynaud phenomenon that responded to Botox treatment. Fast sodium channels conduct axonal signals AT in gap junctions, but have not been shown to be affected by Botox. Myofibroblasts may be involved in late fibrosis of scleroderma patients but do not exist within the vascular smooth muscle.

A 62-year-old woman is evaluated for acute rupture of an extensor tendon after undergoing closed treatment of a nondisplaced distal radius fracture 6 months ago. The tendon most likely to be involved is located in which of the following extensor compartments? A. First B. Second C. Third D. Fourth E. Fifth

C. Spontaneous rupture of the extensor pollicis longus (EPL) tendon is reported to occur in approximately 0.3 to 5% of nondisplaced or minimally displaced distal radius fractures, but it can also occur without trauma or in patients with inflammatory conditions such as rheumatoid arthritis. This is thought to arise from a loss of vascularity and atrophic changes in the compartment, and, because the tendon substance is usually degenerated, primary repair of the tendon is usually not possible. Tendon transfer using the extensor indicis proprius is the standard of care. Spontaneous rupture of other extensor tendons can occur in association with other conditions (e.g., rheumatoid arthritis), but would be exceedingly uncommon in the clinical scenario presented. The EPL passes through the third extensor compartment. Extensor tendon-compartment relationships include the following: First - abductor pollicis longus, extensor pollicis brevis Second - extensor carpi radialis longus, extensor carpi radialis brevis Third - extensor pollicis longus Fourth - extensor digitorum communis, extensor indicis proprius Fifth - extensor digiti minimi Sixth - extensor carpi ulnaris

An 18-year-old female gymnast comes to the office because of the sudden onset of pain, swelling, and ecchymosis of the right ring finger that began 3 days ago while she was practicing hand-only climbing on a rock-wall. Physical examination shows tenderness over the palmar aspect of the finger at the proximal phalanx. Isolated flexion at the distal interphalangeal joint and flexion of the digit at the proximal interphalangeal joint while the remaining digits are held in hyperextension are intact. The patient can fully flex and extend the finger, and the proximal interphalangeal joint is stable to stress. Normal XR. Which of the following is the most likely cause of the findings in this patient? A. Avulsion of the flexor profundus tendon insertion B. Dislocation of the proximal interphalangeal joint C. Rupture of the A2 pulley D. Stenosing tenosynovitis E. Volar plate avulsion fracture

C. Stenosing tenosynovitis (trigger finger) typically results in pain over the metacarpophalangeal (MCP) joint associated with crepitation, clicking, or locking of the digit with altered motion during the flexion-extension arc. Dislocation of the proximal interphalangeal (PIP) joint could account for the symptoms; however the imaging shows the joint to be congruent and the exam did not reveal any instability. An injury originally identified in rock climbers, rupture of the A2 pulley has been increasingly recognized in other sports and activities. The forceful flexion of the flexor profundus and superficialis tendons with the PIP joint flexed 90 degrees and the distal interphalangeal (DIP) joint extended (the "crimp" position) placed loads exceeding the tolerance of the A2 across the palmar PIP joint, resulting in rupture of the underlying pulley. Treatment for an isolated pulley injury includes rest, ice, anti-inflammatory drugs, and external support through use of a ring splint. Avulsion of the profundus tendon (jersey finger) typically presents with loss of flexion of the DIP joint. Pain may be present both at the avulsion site and over the retracted end of the tendon. This patient's examination shows the profundus function to be intact. Volar (palmar) plate avulsion injuries present with pain and swelling at the PIP joint, but the joint will often be painful to stress in hyperextension and potentially, if the injury extends dorsally into the collateral ligaments, it may exhibit instability. X-ray imaging often demonstrates a small bony avulsion fragment (absent in this patient) along the palmar PIP joint.

A 24-year-old man who works as a laborer comes to the office because of a 2-cm mass on the dorsum of each hand. MRI shows an anomalous muscle. Which of the following is the most likely structure? A. Extensor digitorum brevis B. Extensor digitorum longus C. Extensor digitorum brevis manus D. Extensor indicis proprius E. Extensor medii proprius

C. The extensor digitorum brevis manus is an anomalous muscle of the hand, which typically presents as a tender dorsal wrist mass. Incidence in the general population is estimated to be 2 to 3%. Anatomically, this muscle classically originates from the proximal dorsal radiocarpal ligament and inserts into the index finger extensor mechanism. Diagnosis is characteristic on ultrasonography or MRI. Treatment should be directed to symptoms and may include rest, activity modification, fourth dorsal compartment release, and/or muscle excision.

A 14-month-old girl is evaluated for surgical management of the condition shown in the photograph (cleft hand). Which of the following is the most appropriate classification of this congenital difference? A. Duplication B. Failure of differentiation C. Failure of formation D. Overgrowth E. Undergrowth

C. The image shown is a patient with a typical cleft hand, or ectrodactyly. Lobster hand deformity. This is classified as a Swanson type I (failure of formation) congenital difference of the upper extremity. This deformity is caused by a longitudinal growth deficiency of one or more central digits. This condition may have a genetic underpinning and is most commonly inherited in autosomal dominant fashion with approximately 70% penetrance. Ectrodactyly presents with significant heterogeneity. Many patients with cleft hand do not require any type of surgical management. The most important determinants of surgical management are establishment of an appropriate thumb to index webspace for gripping and grasping and release of syndactyly. Surgical management includes elevation of skin flaps, transposition of the index finger to the ulnar side of the cleft, and creation of a web space between the thumb and index finger. Cleft hand is classified with the Thumb-Index Classification of Central Deficiency proposed by Manske. This generally guides the treatment approach in conjunction with management of syndactyly. A myriad of techniques have been employed based upon the severity of the webspace contraction and the presence of syndactyly adjacent to the cleft.

A 4-month-old infant is brought to the office for evaluation of a unilateral, seven-fingered hand with a central index finger flanked on each side by long, ring, and little fingers, with no thumb present. Abnormal expression of which of the following controlling substances is most likely responsible for this developmental anomaly? A. Bone morphogenetic protein B. Fibroblast growth factor C. Sonic hedgehog protein D. Wingless protein

C. The infant's described anomaly is that of a mirror hand, which is an abnormality of the anteroposterior (radioulnar) axis of limb development. Sonic hedgehog protein (SHH) is expressed in the zone of polarizing activity (ZPA) on the posterior (ulnar) surface of the developing limb bud and is the main controlling substance for this axis of development. Direct expression of SHH results in development of the ulna, the ulnar two columns of the carpus, the little finger, the ring finger, and the ulnar half of the long finger. Diffusion of SHH, or long range signaling, results in development of the radial half of the long finger and the index finger. Absence of SHH results in the development of the radius, the radial column of the carpus, and the thumb. Ectopic expression of SHH, such as with duplication of the ZPA at the anterior (radial) margin of the limb bud, results in duplication of the ulnar-sided structures found in a mirror hand. Fibroblast growth factors (FGF) are the main controlling substances in the apical ectodermal ridge (AER) and are responsible for the proximodistal axis of limb bud development. Bone morphogenetic proteins (BMP) are expressed in the AER and are also thought to be involved in digital separation, the lack of which leads to syndactyly. Wingless proteins (WNT) are also expressed in the AER, but it is the WNT signaling pathway from the dorsal surface of the limb bud that controls the dorsoventral axis of limb development. Dorsal ectodermal WNT also maintains SHH in the ZPA such that lack of WNT leads to lack of ulnar ray development. This is contrary to the ectopic expression of SHH leading to duplication of the ulnar rays in mirror hand. Fibroblast growth factors, bone morphogenetic proteins, and wingless proteins are not principal controlling substances for the anteroposterior (radioulnar) axis of development of the limb.

Which of the following vessels runs within the pedicle of the reverse sural artery flap and serves as primary venous drainage? A. Femoral B. Greater saphenous C. Lesser saphenous D. Popliteal E. Posterior tibial

C. The reverse superficial sural artery flap (RSSAF) is a distally based fasciocutaneous or adipofascial flap that is increasingly being used for coverage of defects that involve the distal third of the leg, ankle, and foot. First described by Donski and Fogdestam and later championed by Masquelet et al, RSSAF has become a popular option for these difficult wounds. The description of the RSSAF (Masquelet flap) has revolutionized the osteoplastic armamentarium of surgeons not conversant with microvascular free flaps. The reliability of septocutaneous perforators has been well documented. Hence, raising a flap based on this reliable anastomosis of peroneal artery and median sural artery, along with the sural nerve and lesser (short) saphenous vein has been described to be successful. A significant advantage of this flap is that it does not require sacrifice of a major artery to the lower limb. Touted for its ease of dissection, the RSSAF is often reputed to have a favorable complication profile as evidenced by a recent meta-analysis that found 82% of flaps heal without any flap-related complications. The main complications include venous congestion of the flap requiring delay or leech therapy in some higher-risk patients. The greater saphenous vein runs proximal and medial to the lesser saphenous vein, and it drains the medial and anteromedial portion of the lower leg. The popliteal vein drains the lesser (short) saphenous vein, and it is therefore not the primary drainage of the reverse sural flap. The anterior and posterior tibial veins are the deep venous drainage of the lower leg and do not drain the RSSAF. The femoral vein is the deep venous drainage system in the upper leg.

A 13-year-old girl is brought for evaluation because of a 4-month history of severe pain of the tip of the right index finger. There is no history of trauma. On examination, the finger appears normal with no visible swelling or discoloration. The pain is exacerbated by local pressure when the patient writes and during her weekly swimming lessons. MRI (T2-weighted) image shows enhancing 5mm mass in finger tip. Which of the following is the most likely diagnosis? A. Digital fibroma B. Giant cell tumor C. Glomus tumor D. Neuroma E. Venous malformation

C. This lesion is a glomus tumor. Glomus tumors are benign hamartomas originating from the glomus body, a structure comprised of vascular and neural elements that is responsible for thermoregulation in the skin. These often inconspicuous tumors present with pain, point tenderness, and sensitivity to cold. May have bluish discoloration. X-ray studies may show cortical erosion of the bone adjacent to the lesion, and ultrasonography can provide confirmation. MRI is the most accurate imaging modality and the tumor appears as a bright, discrete mass on T2-weighted images. Digital fibroma is a cutaneous fibroblastic proliferation and would be visible. It rarely causes pain and would not enhance on T2-weighted MRI imaging. Neuroma can cause focal pain as described in the vignette, but the enhancing focal lesion on the T2-weighted MRI effectively rules out solid masses such as neuroma or giant cell tumor (which is common but rarely causes pain or cold intolerance). Venous malformation would enhance on T2-weighted MRI, but would typically present with swelling and would not be as well circumscribed as the lesion shown here.

A 56-year-old woman is evaluated for the sudden, painless inability to flex the interphalangeal joint of the right thumb. Medical history includes rheumatoid arthritis. There is no history of antecedent trauma to the hand. Physical examination shows that flexor pollicis longus tenodesis is absent. X-ray studies show an osteophyte along the volar aspect of the scaphoid. Which of the following is the most appropriate next step in management? A. Anterior interosseous nerve decompression B. Extensor indicis proprius (EIP) tendon transfer C. Palmaris longus tendon grafting with osteophyte resection D. Primary tendon repair E. Observation

C. This patient has an atretic flexor pollicis longus (FPL) tendon rupture due to a scaphoid osteophyte. This is termed a Mannerfelt lesion. FPL ruptures are the most common flexor tendon ruptures in patients with rheumatoid arthritis. The underlying pathophysiology is secondary to osteophyte formation along the volar aspect of the scaphoid. Surgical treatment can include tendon transfer, tendon grafting, or interphalangeal joint fusion to correct the deformity. Treatment should include exploration of the carpal tunnel with resection of the underlying osteophyte to avoid additional attritional tendon ruptures. Due to the fraying of the tendon caused by the osteophyte, primary repair of the FPL tendon is not typically feasible. Treatment options include FDS tendon transfer and palmaris longus tendon graft. EIP tendon transfer is typically employed for extensor tendon ruptures in rheumatoid patients. An incomplete anterior interosseous nerve (AIN) palsy can mimic FPL rupture. Physical examination allows differentiation between AIN palsy and FPL rupture. In the setting of AIN palsy, tenodesis of the IP joint will still be present with MCP hyperextension of the thumb. Initial management of AIN neuropathy consists of observation and splinting. Nerve conduction studies can be of diagnostic as well as prognostic value. Surgical exploration and decompression of the anterior interosseous nerve is a consideration after failure of nonoperative management of a compression neuropathy.

A 53-year-old man comes to the office because of a 2-year history of increasing pain of the radial aspect of the right wrist. X-ray studies show scapholunate disruption and arthritis. Which of the following joints is most likely to be affected first by the arthritic degeneration in this patient? A. Capitolunate B. Radiolunate C. Radioscaphoid D. Radioulnar E. Scaphotrapezio

C. This patient has early-stage scapholunate advanced collapse (SLAC) wrist. SLAC wrist is generally categorized by the Watson classification, which is a descriptive classification but also helps determine management options. The Watson classification is as follows: Stage I: Arthritis between scaphoid and radial styloid Stage II: Arthritis between scaphoid and entire scaphoid facet of the radius Stage III: Arthritis between capitate and lunate While original Watson classification describes preservation of radiolunate joint in all stages of SLAC wrist, subsequent description by other surgeons of pancarpal arthritis (stage IV) observed rare cases in which the radiolunate joint is affected. The radioulnar joint is not affected by SLAC wrist.

A 19-year-old man comes to the office because of persistent left wrist pain after an ATV accident 4 months ago. Medical history includes cast treatment of a wrist fracture. X-ray study shows a proximal pole scaphoid fracture without arthritic changes or collapse. Which of the following is the most appropriate imaging for assessing the vascularity of the bone fragment in this patient? A. Angiography B. CT scan C. MRI D. Triple phase bone scan E. Ultrasonography

C. The most appropriate imaging modality is MRI. This patient has presented with a delayed proximal pole scaphoid fracture/nonunion, which was previously untreated. The primary blood supply to the scaphoid enters distally and travels proximally. As a result, perfusion to the proximal portion of the scaphoid occurs in a retrograde fashion. Fractures of the proximal pole of the scaphoid are located at the furthest distance from the blood supply, and these fragments are at risk for nonunion and avascular necrosis. MRI (particularly with gadolinium enhancement) would be the best imaging study for evaluating the blood supply to the scaphoid fragment and looking for the presence of avascular necrosis. MRI can also provide anatomical information regarding the fracture. Direct intraoperative visualization of bleeding of the fragment has also been advocated in assessing vascularity. Angiography can show blood flow patterns, but would not provide anatomic information. CT scan is useful for detailed anatomic analysis of fractures and assessment of healing, but would be less helpful than MRI in determining avascular necrosis. Bone scan shows the presence of inflammatory activity and can be used in identifying the presence of occult fractures (high sensitivity, albeit with low specificity), but has low resolution and would not be helpful in determining avascular necrosis. Ultrasonography has been used in the diagnosis of acute fractures, but would not determine vascularity.

A 6-month-old boy is brought to the office with a Blauth type IV (pouce flottant) thumb deficiency. Reconstruction with pollicization is planned. Which of the following is the most appropriate new function of the first palmar interosseous muscle? A. Abductor pollicis brevis B. Abductor pollicis longus C. Adductor pollicis D. Extensor pollicis longus E. Flexor pollicis brevis

C. The most appropriate new function of the first palmar interosseous muscle is the adductor pollicis. Thumb deficiencies can be categorized according to the Blauth classification, ranging from hypoplasia (type I) to complete absence (type V). In deficiencies of type IIIB and greater, pollicization of the index finger is the recommended treatment. In pollicization, the index finger is transferred on its neurovascular bundle and a new thumb carpometacarpal (CMC) joint is created using the metacarpophalangeal joint of the index finger. The tendons and muscles of the index finger are used to recreate functions of the new thumb. The extensor digitorum communis is used for the abductor pollicis longus, the dorsal interosseus becomes the abductor pollicis brevis, and the palmar/volar interosseous becomes the adductor pollicis. The extensor indicis proprius is used for the extensor pollicis longus. The flexor tendon is not typically disturbed.

Which of the following peripheral nerve tumors is most commonly associated with von Recklinghausen disease? A. Astrocytoma B. Glioblastoma C. Neurilemoma D. Neurofibroma E. Schwannoma

D. A neurofibroma is a lesion of the peripheral nervous system, which is derived from Schwann cells, other perineural cell lines, and fibroblasts. Neurofibromas may arise sporadically, or in association with von Recklinghausen disease (neurofibromatosis 1 or NF1). A neurofibroma may arise at any point along a peripheral nerve, and comes in two varieties. The plexiform neurofibromas are larger tumors that develop inside the body and tend to intimately involve the nerves, blood vessels, and other structures in the body. They can reside deep inside the body or closer to the skin. Plexiform neurofibromas can cause pain, numbness, weakness, and disfigurement. These tumors do have a small chance of becoming cancerous. Plexiform neurofibromas may also be asymptomatic. Dermal (subcutaneous) neurofibromas are small, nodule-like tumors that grow on or just under the surface of the skin. They can be painful, itchy, disfiguring, or tender when touched, but they have no known potential to become cancerous. Dermal neurofibromas may also be asymptomatic. Schwannomas are peripheral nerve sheath tumors that can be seen with NF1, but are more commonly associated with neurofibromatosis 2. The major distinction between a schwannoma and a solitary neurofibroma is that a schwannoma can be resected while sparing the underlying nerve, whereas resection of a neurofibroma requires the sacrifice of the underlying nerve. A neurilemoma is another name for a schwannoma. Astrocytomas and glioblastomas are tumors of the central nervous system. Astrocytomas and optic gliomas can be seen in association with NF1. A 19-year-old man comes to the office because of persistent left wrist pain after an ATV accident 4 months ago. Medical history includes cast treatment of a wrist fracture. X-ray study shows a proximal pole scaphoid fracture without arthritic changes or collapse. Which of the following is the most appropriate imaging for assessing the vascularity of the bone fragment in this patient? A ) Angiography B ) CT scan C ) MRI D ) Triple phase bone scan E ) Ultrasonography

Which of the following conditions is a relative CONTRAINDICATION for use of the flap in the image shown (Reverse sural artery flap) for reconstruction of an 8 × 10-cm anterior ankle wound? A. Diabetes mellitus B. Hypertension C. Joint exposure with loss of the joint capsule D. Occlusion of the peroneal artery E. Underlying osteomyelitis

D. Hypertension does not preclude the use of any fasciocutaneous flaps in the lower extremity. Diabetes mellitus can be associated with peripheral vascular disease, but by itself, would not prevent successful use of the reverse sural artery flap for foot or ankle reconstruction. Appropriate preoperative workup would include noninvasive ultrasound study of the lower extremity vasculature to prove the peroneal artery was patent. Vascularized flaps, including the reverse sural artery flap, provide excellent coverage for foot/ankle wounds, including those with underlying osteomyelitis. Effective treatment would necessitate adequate debridement and antibiotic therapy as part of the reconstructive paradigm. The distally based sural artery flap receives its blood supply from a few sources, the most robust of which are perforators from the peroneal artery. The most distal of these perforators arise between 4 and 7 cm proximal to the lateral malleolus. Additional perfusion arises from neurocutaneous perforators from the sural nerve and venocutaneous perforators from the lesser saphenous vein.

A 25-year-old man sustains a high-voltage electrical injury of the right upper extremity with an entrance wound over the volar aspect of the wrist. If increased compartment pressures are not adequately relieved in time, which of the following muscles is most likely to develop an ischemic contracture? A. Brachioradialis B. Extensor carpi radialis brevis C. Flexor carpi radialis D. Flexor digitorum profundus E. Palmaris longus

D. The above patient did not undergo forearm compartment release and has flexion contractures of the interphalangeal joints of the fingers and thumb due to ischemic necrosis of the flexor digitorum profundus (FDP) and flexor pollicis longus (FPL). Volkmann ischemic contracture is the end result of untreated compartment syndrome. The deeper muscles in the forearm sustain higher pressure sooner and for longer, causing them to be the most affected by compartment syndrome. The FDP to the middle and ring fingers lies against the ulnar and interosseous membrane in the deep compartment of the forearm. These two muscle segments, in addition to the remaining segments of the FDP to the index and small fingers and the FPL, are the most likely to develop contracture. All other muscles listed are more superficial. While brachioradialis, palmaris longus, extensor carpi radialis brevis, and flexor carpi radialis can all become necrotic in untreated compartment syndrome, FDP and FPL are the most likely to do so due to their depth in the forearm.

A 53-year-old woman is evaluated for a 1-year history of numbness and tingling of the thumb and the index and long fingers of the right hand. She has been unresponsive to conservative treatment. An increase in which of the following is most likely suggestive of carpal tunnel syndrome in this patient? A. Abductor digiti minimi fibrillations B. Adductor pollicis fibrillations C. Motor nerve conduction velocity D. Sensory distal latency E. Sensory nerve conduction velocity

D. The diagnosis of carpal tunnel syndrome is primarily a clinical diagnosis; however, electrodiagnostic studies (EDX) may be helpful in confirming the diagnosis. While these EDX studies are commonly referred to as "EMGs,"' they are actually two separate studies: the nerve conduction studies (NCS) and the electromyography (EMG). NCS examine both the sensory and the motor nerve fibers. Sensory nerve conduction studies measure sensory nerve action potential, and the motor nerve conduction studies evaluate a compound muscle action potential. The NCS also measures the amplitude of both the compound muscle action potential and sensory nerve action potential. Nerve conduction velocity (NCV), the velocity of the nerve's action potential between two points, is also measured by the nerve conduction studies. The EMG tests the muscle itself. The needle electrode examination can measure motor unit potential (MUP). MUP is measured in regards to its amplitude, duration, wave shape, and firing pattern. In the diagnosis of carpal tunnel syndrome, particular attention is given to the MUP of the abductor pollicis brevis muscle, which is uniquely innervated by the median nerve after it passes through the carpal tunnel. In the diagnosis of carpal tunnel syndrome, changes in the sensory nerve are detected earlier in the carpal tunnel process than motor changes. Early NCS changes (as compared to standardized normal values) include prolonged or increased sensory distal latencies. Prolonged motor latencies (also abnormal) are detected less frequently than the sensory latency changes, and detected in only 35 to 50% of patients with carpal tunnel syndrome. Motor amplitude change, found in carpal tunnel syndrome, is detected even less commonly. A conduction block, or slowing of the nerve's action potential velocity (NCV) between two points, can be seen with carpal tunnel syndrome. The needle electrode examination (EMG) is normal in more than 60% of patients with the diagnosis of carpal tunnel syndrome. Fibrillations in the abductor pollicis brevis occurs in generally less than 20% of patients with carpal tunnel syndrome. The adductor pollicis brevis and abductor digiti minimi muscles are innervated by the ulnar nerve, and would not show any electrodiagnostic evidence of muscle instability in isolated carpal tunnel syndrome.

A 21-year-old man sustains traumatic amputation of the right thumb at the level of the metacarpal base. Pollicization should include osteosynthesis of which of the following? A. Index metacarpal base to trapezium B. Index metacarpal to thumb metacarpal C. Index middle phalanx to thumb metacarpal D. Index proximal phalanx to thumb metacarpal E. Index proximal phalanx to trapezium

D. Transfer of the index finger to the thumb position on the hand (pollicization) typically transfers the proximal phalanx to the thumb metacarpal, as long as the base of the thumb metacarpal is preserved. Transfer of the middle phalanx or metacarpal of the index would create a neo-thumb that is too short or too large, respectively. Obliterating an intact carpometacarpal joint by transferring the index metacarpal to the trapezium would eliminate palmar and ulnar abduction of the thumb and compromise global hand function.

A 30-year-old man is evaluated for a hand injury after punching a wall. X-ray study shows a fracture of the fifth metacarpal neck. Which of the following findings is most likely to require surgical intervention? A. Angulation B. Callus formation C. Impaction D. Malrotation E. Shortening

D. Malrotation causes scissoring of the affected digit, which will adversely affect neighboring digits. This will affect activities of daily living and is an indication for operative intervention. Other indications for operative intervention include displaced intra-articular fractures, severe soft-tissue injury, unstable open fractures, segmental bone loss, and multiple fractures. Angulation is usually dorsal tip-oriented because of intrinsic and extrinsic muscle pull. A good rule of thumb is the 10, 20, 30, 40 for digits two, three, four, and five. The fourth and fifth digits have carpometacarpal joint mobility and can tolerate larger angulation. The fifth digit metacarpal may even tolerate up to 70 degrees of angulation as long as there is no extensor lag. Impaction can lead to shortening and/or angulation, which is tolerated more than rotational deformities. Similarly, shortening is well tolerated as long as there is no extensor lag. Nonoperative complications include aesthetic with loss of knuckle and possible pain in the palm from the metacarpal head. Callus formation is indicative of an old, healed fracture.

A 40-year-old man sustains an avulsion of the weight-bearing portion of the medial heel. Coverage with an instep flap is planned. Sensation to this flap is provided by which of the following? A. Lateral plantar nerve from the deep peroneal nerve B. Lateral plantar nerve from the superficial peroneal nerve C. Lateral plantar nerve from the sural nerve D. Medial plantar nerve from the deep peroneal nerve E. Medial plantar nerve from the tibial nerve

E. The medial plantar artery flap, or instep flap, provides sensate, full-thickness glabrous skin and subcutaneous tissue that can be transferred as a pedicled or free flap. The tissue is well suited for weight-bearing areas of the foot but has also been used as a free tissue transfer for palmar defects. Because the instep donor site is non-weight-bearing, the donor site can be covered with a skin graft. The innervation of the medial instep flap comes from the medial plantar nerve, a branch of the tibial nerve.

A 53-year-old woman comes to the office after undergoing fixation of a humerus fracture 17 months ago. Physical examination shows inability to extend the wrist, fingers, and thumb. This has been present since the time of injury, without any recovery of function. Tendon transfers are planned. Transfer of which of the following muscles is most appropriate for restoration of wrist extension? A. Brachioradialis B. Flexor carpi ulnaris C. Flexor digitorum profundus D. Palmaris longus E. Pronator teres

E. The most appropriate muscle to transfer for restoration of wrist extension is the pronator teres. The radial nerve can be injured as a result of humerus fracture and/or surgery as it crosses the spiral groove of the humerus. The resultant radial nerve palsy will cause inability to extend the wrist, fingers, and thumb. Reinnervation of the muscle ideally should be completed within 12 to 18 months after injury to allow for recovery. In this patient, who has high radial nerve palsy after humerus fracture, the time following injury has been too long, so nerve repairs or nerve transfers are not a viable option, and tendon transfer is the procedure of choice. Tendon transfer involves the use of a noncritical or expendable donor tendon to provide a missing function. The tendon to be transferred should have adequate strength and range of motion to provide the desired function. Ideally the tendon used should have synergistic action and allow for tenodesis to facilitate reeducation. The pronator teres is a median nerve-innervated muscle that has adequate power and excursion to provide wrist extension. It is typically transferred to the extensor carpi radialis brevis (as opposed to the extensor carpi radialis longus) in these cases to provide for more centrally oriented wrist extension. The brachioradialis is a radial nerve-innervated muscle and will not be functioning in this patient who has a high radial nerve palsy. In low radial nerve palsies, it can be used to restore thumb extension. The brachioradialis can also be used to restore finger or wrist extension, as well as finger or thumb flexion in the appropriate patient. The flexor carpi ulnaris would have adequate power and excursion, but it is not synergistic and it would be difficult to learn to use a wrist flexor to power wrist extension, as it provides an opposite function. This is typically used to restore finger extension, as it would take advantage of the tenodesis effect. The flexor digitorum profundus would be synergistic with wrist extension, but it does not have independent muscle bellies and its use would require sacrifice of important finger flexor activity. The palmaris longus does not have sufficient power to provide for wrist extension. It can be used as a transfer for thumb extension.

A 30-year-old Florida fisherman comes to the emergency department 24 hours after cutting his palm with a fish-scaling knife. Blood pressure is 90/50 mmHg and heart rate is 120 bpm. Physical examination shows severe swelling of the hand, hemorrhagic bullae of the hand, and erythema to the mid forearm. X-ray study shows no gas within the soft tissues. A Gram stain of drainage from a bulla reveals gram-negative bacilli. Which of the following infectious agents is the most likely cause of the patient's symptoms? A. Clostridium perfringens B. Mycobacterium marinum C. Pseudomonas aeruginosa D. Staphylococcus aureus E. Vibrio vulnificus

E. The patient described has necrotizing fasciitis and sepsis. Vibrio vulnificus is a gram-negative bacillus, a cause of necrotizing fasciitis, and is commonly associated with warm saltwater environments (Florida). It also tends to present with hemorrhagic bullae. Staphylococcus aureus is a gram-positive coccus, is not associated with watery environments, and is more commonly associated with pustules rather than hemorrhagic bullae. Clostridium perfringens is a gas-forming, gram-positive bacillus, and is associated with marine sediment. Pseudomonas aeruginosa, also a gram-negative bacillus, although associated with moist environments, is more typically associated with less aggressive soft-tissue infections. Mycobacterium marinum is also associated with watery environments, but tends to affect aquarium owners with an indolent granulomatous process.

A 60-year-old woman with a history of rheumatoid arthritis presents with a boutonnière deformity of the long finger. Which of the following is the most likely cause of the deformity? A. Destruction of the cartilage of the proximal interphalangeal joint B. Dorsal subluxation of the lateral bands at the proximal interphalangeal joint C. Metacarpophalangeal joint subluxation D. Rupture of the distal extensor tendon E. Synovitis at the proximal interphalangeal joint

E. The posture of a boutonnière is flexion of the proximal interphalangeal (PIP) joint and hyperextension of the distal interphalangeal joint. The common injury for non-rheumatoid patients that suffer traumatic injuries that lead to the deformity is a rupture of the central slip that means no active extension at the PIP joint. Over time, the lateral bands slip volarly and cause hyperextension of the distal joint. Synovitis of the PIP joint leads to subsequent attenuation of the central slip, which leads to the same deformity.

A 61-year-old man comes to the office for evaluation of a 3 × 3-cm calcaneal defect with exposed bone. Medial plantar flap reconstruction is planned. The principal blood supply to this flap arises from which of the following arteries? A. Arcuate B. Dorsalis pedis C. Peroneal D. Plantar arch E. Posterior tibial

E. The primary blood supply to the medial plantar flap is the medial plantar artery, a terminal branch of the posterior tibial artery. The dorsalis pedis is the continuation of the anterior tibial artery and does not contribute to this flap. The peroneal artery is a proximal branch of the posterior tibial artery and descends in the deep posterior compartment posterior to the tibialis posterior and anterior to the flexor hallucis longus; it does not contribute to this flap. The arcuate artery is the terminal branch of the anterior tibial artery. The plantar arch runs on the plantar aspect of the foot at the level of the metatarsals; it is formed from a confluence of the lateral plantar artery and the deep plantar artery from the dorsalis pedis.

A 50-year-old male construction worker is evaluated for weakness of grip and pinch with inability to touch index finger to thumb. The patient is referred from a neurologist with a diagnosis of anterior interosseous nerve syndrome. Which of the following muscles is most likely to be spared? A. Flexor digitorum profundus to index B. Flexor digitorum profundus to middle C. Flexor pollicis longus D. Pronator quadratus E. Pronator teres

E. The pronator teres is innervated by the median nerve prior to its take off of the anterior interosseous nerve (AIN), which is why it cannot be affected by AIN syndrome. Pronation generated by the pronator teres or the pronator quadratus would be indistinguishable clinically. The AIN is a terminal branch off the median nerve that innervates the flexor digitorum profundus to the index and middle fingers, flexor pollicis longus (FPL) and pronator quadratus. The AIN arises from the median nerve approximately 4 to 6 cm distal to the medial epicondyle. It travels between the flexor digitorum profundus (FDP) and flexor digitorum superficialis (FDS) initially, and then between the FPL and FDP. Then it lies on the volar surface of the interosseous membrane and travels with the anterior interosseous artery, terminating in the pronator quadratus and then the wrist joint capsule and the intercarpal, radiocarpal, and radioulnar joints. The nerve originates from C5-T12, becoming the medial and lateral cords of the brachial plexus and then becoming the median nerve. Patient can't make an A-Okay sign. Site of compression is tendinous edge of deep head of pronatorteres or tendinous origin of FDS