Foot Amputations in the Diabetic Population

Steps post-amputation after closure?

• Take deep culture • Compression dressing • Ambulation determined by procedure • Continue Antibiotics post-operatively depending on your intraoperative findings, pathology specimen, and microbiology culture results

Overall goal of Lower Limb Amputations

*Create a modified locomotor end-organ that will interface comfortably with a prosthesis, orthosis, or modified footwear,* fulfilling the goal of amputation as the first step in restoring the diabetic's quality of life to an acceptable level.

Common Causes for amputations in Diabetics?

- "wet" gangrene - Sensory neuropathy and direct/shear forces - Surgical or Non-Surgical treatment of Charcot neuroarthropathy - Thermal injuries, dysvascularity

Syme Ankle Technique Incision?

- 1-1.5 cm below and anterior to the tips of the malleoli - Dorsally incision goes to just below the anterior edge of the tibia at the ankle joint and is carried down to the dome of the talus - Medially and laterally the incisions go straight to the sole and across - Plantar incision carried down to bone

1st MTPJ, should keep what tendon to keep dorsiflexion?

Retain extensor tendon if it is not involved to keep active dorsiflexion

Isolated 2nd, 3rd, or 4th metatarsals amputations - Affects only? - Resect? leaving only what joint intact?

- Affects only width of forefoot - Resect through the proximal metaphysis (resection in the middle third), leaving tarsometatarsal joints intact

Basic steps of Debridement of soft tissue?

- Drain abscess - Leave open/delayed closure OR place drain so pathogens may exit - Dilution through irrigation - Antibiotics based on cultures - Clinical re-assessment • Removal of obviously infected and necrotic tissue • Removal of all poorly vascularized tissue (Articular cartilage, joint capsules, tendons, plantar plate) • All visibly uninvolved, well-vascularized tissue should be saved for secondary reconstruction

Expected functional outcome of Single lesser ray amputation - level of functionality? - Is rollover function intact? - is width or length affect?

- Good result cosmetically and functionally - Rollover function during terminal stance remains essentially normal - Width of forefoot is affected

Treating Ischemia (if wet) -Limit? - Evaluate?

- Limit/prohibit weight bearing - Evaluate wound for tracking - Evaluate wound for probe to bone - presumptive diagnosis of osteomyelitis - Evaluate vascular status and radiographs - Debride wound, it is exploratory, extend of debridement may be due to findings while in the OR (while trying to be conservative)

*Expected functional outcome of First ray amputation:* - Affect to the medial column? - How to keep/ restore arch?

- Long medial column is essential to proper foot function during stance and progression, so this level amputation is devastating. - Important to restore medial arch with orthotic (directly related to length of the first met shaft preserved)

Hallux: MTPJ disarticulation - Windlass mechanism, how is it affected? - Reason leading to this procedure? - Release what tendons? - Remove sesamoids? - Work on 1st met head?

- Loss of windlass secondary to removal of flexor hallucis brevis/sesamoid complex. - Entire proximal phalanx infection - After release of flexor hallucis brevis tendon insertions on the proximal phalanx, sesamoids displace proximally exposing crista on plantar surface of first metatarsal head. (If crista is prominent, should be removed) - Sesamoids will be prominent and are avascular, so remove. Remove sesamoid fibrocartilaginous plate and articular cartilage - Smooth 1st metatarsal head with file/burr/saw

Most common causes of 1st ray amputations? Why leave as much metatarsal length? Why bevel plantar surface? Best practice if more then the 1st ray is involved?

- Most common cause is ulcer sub 1st met head - leave as much metatarsal length as possible to allow for elevation of the medial arch with custom molded insert - Bevel plantar aspect to avoid area of increased pressure - If 1st ray and any additional ray is involved, it may be best to do a TMA

Basic steps of Debridement of Osteomyelitis?

- Must remove involved bone (biopsy) - Antibiotic must be able to penetrate bone - Antibiotic beads left locally to elute antibiotics • Removal of obviously infected and necrotic tissue • Removal of all poorly vascularized tissue (Articular cartilage, joint capsules, tendons, plantar plate) • All visibly uninvolved, well-vascularized tissue should be saved for secondary reconstruction

Removal of lesser toes may cause clinical difficulty - Will partial digits amputations drift? - Will fully disarticulated digits cause drift?

- Partial digital amputation preserves some function and allows the digit to act as a buttress to adjacent digits to stop drift - Digital disarticulation does not preserve attachment of intrinsics and thus no buttress is maintained for adjacent digits

Function most affected by disarticulation of great toe at MTPJ?

- Progression of moving center of plantar pressure during stance shifts laterally (from 2nd to 3rd)

Bone cuts for Transmetatarsal Amputation:

- Shaft cuts should begin medially within the distal metaphysis of the first metatarsal, with each metatarsal shaft made slightly shorter as one proceeds laterally - Cuts parallel normal toe break of the shoe - Bevel metatarsals plantarly to reduce distal peak pressure during rollover

Factors Affecting Wound Healing

- Tissue O2 - Glucose control - Neuropathy - Tissue atrophy - Biomechanics

Isolated 5th metatarsals amputations - Direction of cut? - Why leave partial shaft?

- Transect obliquely with an inferolaterally facing facet - Uninvolved 1⁄2 to 3⁄4 of shaft left to enhance WB area and to preserve insertion of Peroneus Brevis tendon

Treating Ischemia (if dry)

- if dry, there is ample time to allow demarcation of healthy and dead tissue. - Consult vascular surgery if there is a vascular impairment before necrosis tissue. Not surgical emergency.

How to determine level of amputation?

- proximal to damaged tissue - O2 perfusion (are they a smoker?) - Skin available to close procedure - Patient compliance - Activity level ( in a wheel chair?) - Family support

Why to avoid leaving the lesser toe (5th) isolated?

Avoid leaving a lesser toe isolated by removing the toes on either side as it may make digit susceptible to injury.

Hallux amputation: *Distal/Terminal Symes amputation* - Causes? - Removes? - Make directional cut ? - Retain what tendons ?

Causes: - Chronic ulceration of digital tip - Osteomyelitis of tip of distal phalanx - Traumatic avulsion of tip of digit • Removes nail matrix and nail bed • Bone cut through distal phalanx perpendicular to the WB surface • Retains insertion of extensor and flexor tendons

Syme Ankle Technique closure

Closure (by layers) with *heel pad centered under tibia.* - Suture plantar fascia to the anterior tibial cortex through drill holes - Suture Achilles tendon to the posterior tibial cortex through drill holes

What is a Syme Ankle Disarticulation, and what leads to it?

Spread of infection into the heel pad or ankle joint or along tendon sheaths proximal to the ankle joint generally requires an ankle disarticulation with opening of involved crural compartments and a delayed transtibial amputation

How to maintain Hemostasis in the OR?

Use of tourniquets - Contraindicated in patient with h/o revascularization - No complications with the use of tourniquets at any level except AKA Consider not using tourniquet unless necessary - Ligation, coagulation, and compression - Better evaluation of viable and uninfected tissue

What is the advantage of Soft tissue flap for partial foot amputations/disarticulations?

• *Ensure patient has soft tissue envelope over most surfaces of the foot is mobile (not adhering to underlying bone)* • Avoid split thickness skin grafts (STSG) on distal, medial, lateral, and plantar surfaces of the residual foot

Ray Resection Surgical Technique - incision type for 1st and 5th? - type of angle to cut the lessers? - dissection by layers? - Does it matter to Disarticulate before cut? - Where to bevel? - Type of wound cleansing? - Deep or shallow closure? - Dressing?

• 1st and 5th rays use a racquet incision • Converging semielliptical incisions for lesser rays • No dissection by layers • Disarticulate at MTPJ and then cut met • Bone cut beveled from dorsodistal to proximoplantar. • High pressure lavage with 2-4 liters • Gram stain and culture after lavage if indicated • No deep closure (use of retention stitch) • Compression dressing

Syme Ankle Technique - Cauterize what artery? - Caution of nerve bundle?

• Anterior tibial artery is ligated/ cauterized • Caution with posterior tibial neurovascular bundle which should be tied off, utilize blunt dissection in this region

Lesser Toe Amputation: 2nd digit Distal IPJ - Common mechanical pathology?

• Common with insensate mallet toe, Shortens toe so that it no longer projects beyond the adjacent toes

Postoperative Management of digital amputations: Do best to list 7...

• Compressive dressing • Immediate postoperative X-Rays • Ambulation allowed in postoperative shoe • If amputation for infection continue antibiotics for two weeks • Dressing change at one week to evaluate for infection • Suture removal at its earliest is three weeks • Progress to normal shoes with filler prn

Lesser Toe Amputation: 2nd digit MTPJ - How can this create a problem? - Best practice in removing the digit? - Exposure of cartilage may lead to? - Benefit in narrowing?

• Creates problem by removing lateral support to great toe and can create hallux valgus deformity which may create potential for medial 1st MTPJ ulceration • May be better to remove the second metatarsal through its proximal metaphysis along with the toe • Allows exposure of metatarsal head cartilage which is avascular and prone to infection • Foot can then narrow as the first and third metatarsals approximate each other giving more cosmetic and functional result

*Midtarsal (Chopart) amputation?* - Where is the disarticulation? - Why rarely used in diabetic patients? - Advantages over symes and bka? - Excision of what portion of calcaneous is also recommended?

• Disarticulation is through the talonavicular and calcaneocuboid joints, leaving only hindfoot (talus calcaneus) • Used rarely in diabetic foot infections because of the proximity to heel pad • Advantageous over Syme's and BKA in that patient can still be fitted with an AFO (Ankle-Foot Orthosis shoe) in a regular shoe rather than knee-high prosthesis • Excision of the sharp anteroinferior corner of the calcaneus recommended

Syme Ankle Disarticulation - preserve what for wb? - What is indacted in order for this level amp? - Contradictions? - what must be preserved?

• Disarticulation through the ankle joint with preservation of heel flap to permit weight- bearing at end of stump • Indicated ininability to salvage a more distal functional level in an infected and/or dysvascular foot with an adequate posterior tibial artery • Contraindications include poor Posterior tibial blood flow, infection of heel pad, ascending and uncontrolled lymphangitis • Must preserve posterior tibial neurovascular structures and fat filled fibrous chambers of heel pad

Syme's Amputation Complications

• Failure of wound healing • Mobility and displacement of the soft tissue stump • Trauma to major nerves and/or vessels • Recalcitrant heel pain

BKA Complications

• Failure of wound healing • Prosthetic intolerance • Stump ulceration • Need for higher level ablation

*Tarsometatarsal (Lisfranc) Amputation?* - Risk if not failure to control infection at this point? - Forefoot lever? *- Preserve what tendons?* *- Reattach what tendons?* - Keystone bone?

• Failure to control infection at this level will risk of Syme ankle disarticulation or BKA. • Lisfranc disarticulation results in a major loss of forefoot lever length *• Preserve tendon insertions of peroneus brevis, peroneus longus, and tibialis anterior muscles to maintain a muscle balanced residual foot • PL and TA distal insertion on 1st met base can be reattached to medial cuneiform for reinforcement* • 2nd metatarsal base (keystone) should be left in place to preserve the proximal transverse arch

On the foot Flaps are ideally formed of ? True/ false: You can handle flaps with forceps? Why do we contour underlying bone in amputation?

• Flaps are ideally formed of plantar skin, subcutaneous fat, and investing fascia, fashioned so that wound closure isn't under tension • Never handle flaps with forceps during surgery • Proper contouring of underlying bone ends to prevent soft tissue envelope damage

Transtibial Amputation (Below-the-Knee Amputation) - Reason leading to this amp? - Preserve what in tibia? - Stump length, and fx?

• Foot cannot be saved and knee joint is usable • Shortest useful transtibial amputation must include *tibial tubercle to preserve knee extension* by the quadriceps with flexion provided by the semimembranosus and biceps femoris. • Longer stump is more efficient

Hallux: Partial Digital Amputation - Thickness? - What level of disarticulation? - Direction of cut?

• Full thickness incision, no layers • Disarticulated at PIPJ or IPJ • Proximal phalanx resected with power saw perpendicular to weight bearing surface

Guillotine Amputation

• Guillotine amputation leaves an open wound at the end of the stump • Precludes use of otherwise salvageable tissues in preserving forefoot length • Second stage involves a higher level of amputation with further planning to create soft tissue flaps and provide skin cover over open end of stump

*Ray Resection Postoperative Management* - When to take X-rays? - WB or NWB? Splint? - Antibiotics - How often dressing change? - What week we remove sutures? - When to partial wb? - when to full wb?

• Immediate postoperative X-Rays • NWB is posterior splint • Abx for 2x weeks if amputation is for infection • Dressing change at one week • Suture removal at 3 weeks • Partial WB in postoperative shoe at 3 weeks • Full WB in regular shoes at 6 weeks

Hallux amputation: *Partial Digital Amputation* IPJ level disarticulation - Trim? - Lengthen or shorten tendon? - Is this amputation wb?

• Might be necessary to trim condylar prominences of the proximal phalanx medially, laterally, plantarly as well as shorten it slightly by removing the articular cartilage. • Shorten the FHL tendon at the level of the IPJ • Proximal phalanx will continue to aid in standing balance owing to preservation of the windlass mechanism in contrast to disarticulation at the MTPJ

Expected Functional Outcome of Syme Ankle disarticulation?

• More energy efficient than proximal transtibial level amputation • Calf atrophy over time, must maintain position of prosthesis

TMA Surgical Technique - Dissection by layers? - Shape of cut across mets? - Vessels? - Clean out? - Culture - Drain needed? - Closure? - Dressing?

• No dissection by layers • Bone cuts with • Bone cuts create metatarsal parabola (power saw) and beveled. • Vessels are ligated or cauterized • High pressure lavage with 2-4 liters • Gram stain and cultures after lavage • Drain is not necessary • May or may not have deep closure and skin closed with 3-0 or 4-0 monofilament suture • Compression dressing

*Expected Functional Outcomes of Midtarsal Disarticulation* - Rollover? - Walk w/ or wo/ prosthesis? - Type of shoe needed?

• No rollover function but allows end weight- bearing • Amputee can walk without a prosthesis for short distances • Close fitting rigid ankle foot prosthesis or orthosis and a shoe with a rigid rocker sole required

Footwear for patient post-op of lesser amp?

• Place patient in diabetic shoes with custom molded inserts (firm sole with soft molded inserts) with filler

Integral part of proximal flaps? T/F? Flaps should have tension? Where should nerves and tendons be transected?

• Proximal flaps have muscle tissue as an integral part • No tension on flaps at closure • Nerves and tendons are transected under tension so they will retract

Chopart's Amputation Complications - Balancing? - Deformity resulting? - Wound, leading to?

• Rebalancing errors with tendon transfers • Equinus deformity with recurrent ulceration of the stump • Wound dehiscence and further spread of infection leading to: higher level amputation.

*Hallux* amputation: *Partial Digital Amputation* Why do we want to salvage the proximal phalanx?

• Salvage base of proximal phalanx if uninfected to *keep sesamoid bones beneath the metatarsal head, saving windlass mechanism*

*Function Outcome of TMA* - Ability to walk? *- Success depends on?* - Type of shoes needed, filler? - Avoid short shoes why? - Prostheses ?

• Satisfactory outcome in walking function • Success depends on preservation of insertion of peroneus brevis, peroneus longus, and anterior tibial tendons • Shoe should be stiff rocker sole to avoid distal ulcers from a flexible shoe sole (Distal filler needed to maintain shape of toebox) • Avoid a custom-made short shoe because of the shortened forefoot lever arm. • Supramalleolar prostheses for TMA can be fitted

Expected functional outcome of Tarsometatarsal disarticulation? - walking function? - how to restore?

• Significant loss of forefoot length with decrease in barefoot walking function. • To restore fairly effective late stance phase walking function, fitted fixed ankle foot prosthesis/orthosis required and placed in a shoe with rigid rocker bottom

Grodinsky/Loeffler and Ballard incision ?

• Single extensile plantar incision • Grodinsky (later Loeffler and Ballard) - Begins posterior to medial malleolus and ends distally between the first and second metatarsal heads

Below-the-Knee Amputation Technique - Type of flap to close? - Cut bone? - Flap should be what ratio? - Layer dissection? - How is fibula cut? - Muscular flap? - Ligated vessels - Drainage? - Suture to close?

• Stump is closed with longer posterior flap or side to side flaps (Flaps and lengths of stump adjusted if gangrene, ulceration, or infection extends into proposed area) • Bone best cut in distal three quarters of tibia, contour the tibia • Posterior flap length is 2/3 the diameter of the leg • No dissection by layers • Fibula cut 2cm above level of the tibia cut with a proximolateral to distomedial bevel • Posterior musculature of flap is cut to one-half its thickness • Large vessels ligated and then cuff can be released • Lavage and drain prn • Suture aponeurosis to tibial periosteum and skin is closed with horizontal mattress sutures

Inherent Complications of amputations of digits? name 5

• Stump neuroma • Wound dehiscence • Further spread of infection • Structural deformities (HAV, etc) • Stump ulceration

Ray Resection Complications

• Stump neuromas, wound dehiscence, and further spread of infection. • Transfer lesion and ultimate ulceration • 1st ray amputations can result in metatarsalgia and stress fractures

*Bone cuts for Transmetatarsal Amputation: * • When is a Tendo-Achilles lengthening (TAL) needed, reduced what pressure? • How many weeks of NWB? • What if Ant-tib weakness?

• Tendo-Achilles lengthening (TAL) or tenotomt if no passive ankle dorsiflexion present (Effectively reducing distal peak pressures over the metatarsal shafts at the end of stance phase.) • Usually requires 6 weeks of Non WB till wound is sound and stiff rocker sole with custom molded inserts are fitted and ready • If patient has Tib-Ant weakness, well padded ankle foot orthosis is necessary

Midtarsal (Chopart) technique unevitable secondary deformity? and how to correct/ prevent?

• Unevitable equinus deformity secondary to loss of dorsiflexors and myostatic contracture of the unopposed gastrosoleus - Can reattach tibialis anterior tendon to talar head - Can reattach tibialis anterior and peroneus brevis tendons to the talus - Can remove 2-3 cm of the Achilles Tendon/Achilles tenotomy - Cast in dorsiflexed position for 6 weeks with changes as necessary for wound evaluation

Above-the-Knee Amputation - when indicated ? - risk factors ? - use tourniquet ?

• Usually indicated in diabetic dysvascular patient with marked compromise of the blood supply to the whole lower limb • Because of advanced age or general debility, relatively few of these patients become full prosthetic users • Avoidance of tourniquet at this level results in better chance of success

TMA complications?

• Wound dehiscence and further spread of infection • Equinus deformity and stump ulceration • Need for higher level amputation