Kine Ch 15
Biceps femoris, semitendinosus, semimembranosus
3 primary muscles that flex the knee
18
A Q-angle greater than ______ degrees in women can predispose the individual to patellar injuries
IT Band Friction Syndrome
AKA Runner's knee
ACL
Anterior aspect of tibia- crossing up and backward to attach on the posterior lateral femoral condyle
OSD
Apophysitis of the tibial tubercle
MCL
Approximately 8-9 cm long and divided into a deep and superficial layer.
Pes anserine
Area where muscles attach
Patella
Articular surface is divided up into 3 facets, each covered with up to 5mm of hyaline cartilage
Proximal knee
Articular surface of medial condyle is longer than the lateral and flares outward posteriorly
MCL
At 30° of flexion, 78% is the main restrain, along with ACL-PCL (13%), and capsule (7%).
Absorb and dissipate force Improve the congruency of the joint
Because the medial and lateral condyles of the femur differ somewhat in size, shape, and the menisci of the knee function to... (2)
Prepatellar bursa
Between skin and anterior surface of the patella, allowing free movement of the skin over the patella during flexion and extension
Superficial infrapatellar bursa
Between skin and patellar tendon
Deep infrapatellar bursa
Between the tibial tubercle and the infrapatellar tendon and is separated from the joint cavity by the infrapatellar fat pad; reduces friction between the ligament and the bony tubercle
Hemarthrosis
Blood in a joint cavity
Menisci
Blood supply comes from the genicular arteries with vascular penetration to the peripheral 10-30%
Deep, subpopliteal, semimembranosus
Bursae located inside the joint capsule (3)
Prepatellar, superficial infrapatellar, and deep infrapatellar
Bursae located outside the joint capsule (3)
Medial meniscus
C shaped; entire peripheral border is firmly attached to the medical capsule
Joint mice
Chips of cartilage loose within the joint that cause clicking or locking of the knee
ACL Sprain
Clinical Presentation Experiences a pop with severe pain and disability Rapid swelling at the joint line Positive anterior drawer and Lachman's
Patellar Tendinitis
Clinical Presentation Pain and tenderness at inferior pole of patella and on posterior aspect of patella with activity.
OSD
Clinical Presentation Swelling, hemorrhaging and gradual degeneration of the apophysis due to impaired circulation. Pain with activity, tenderness over anterior proximal tibial tubercle.
Meniscus injuries
Clinical Presentation Diagnosis is difficult Effusion develops over 48-72 hrs Joint line pain, loss of motion Intermittent locking and giving way Pain with squatting
MCL Sprain
Clinical Presentation- Grade I; Little fiber tearing or stretching Stable valgus stress test Little or no joint effusion Some joint stiffness-point tenderness on medial aspect of the knee Relatively normal ROM
MCL Sprain
Clinical Presentation- Grade II; Complete tear of deep capsular ligament-partial tear of superficial layer of MCL No gross instability; but laxity exists Slight to moderate swelling Moderate to severe joint tightness with decreased ROM Pain along medial aspect of knee.
MCL Sprain
Clinical Presentation- Grade III Complete tear of supporting ligaments Complete loss of medial stability, meniscus disruption Moderate to severe swelling Immediate pain followed by ache Loss of motion due to effusion and hamstring guarding Positive valgus stress test.
PCL Sprain
Clinical Presentation: "Pop" in the back of the knee Tenderness, relatively little swelling around popliteal fossa Laxity with stress tests.
IT Band Friction Syndrome
Clinical Presentation: Irritation at band's insertion. Tenderness, warmth, swelling, and redness over lateral femoral condyle. Pain with activity. Positive Ober's test, laterally tracking patella.
Chondromalacia Patella
Clinical Presentation: Pain with walking, running, stairs and squatting Possible recurrent swelling, grating sensation with flexion and extension.
Acute Patella Subluxation or Dislocation
Clinical Presentation: With subluxation, pain and swelling, restricted ROM, palpable tenderness over adductor tubercle Dislocations result in total loss of function First time dislocation = assume fracture.
LCL sprain
Clinical Presentation; Pain/tenderness Swelling Joint laxity with varus testing.
Proximal knee
Condyles are bifurcated by the intercondylar notch
PCL
Controls and imparts rotational stability to the knee; Prevents hyperextension of the knee and femur.
ACL
Critical stabilizer preventing: Anterior translation of the tibia on a fixed femur. Posterior translation of the femur on a fixed tibia. Internal rotation of the tibia on the femur. Hyperextension of the tibiofemoral joint. Secondary stabilizer to valgus and varus position.
ACL
Deceleration combined with a cutting motion is a common mechanism of injury for the...
MCL
Deep fibers of this are shorter and blend into and fuse with the joint capsule and medial meniscus.
Chondromalacia
Degeneration of the articular cartilage on the posterior aspect of the patella caused by friction over the femoral condyles
Avascular
Devoid of blood circulation
OSD
Disease that occurs usually in adolescent boys in which stress on the distal attachment of the quads mechanism causes repeated avulsion; consequently more bone cells are laid down, forming calcification over the attachment of the tendon on the tibial tuberosity
Menisci
Disks of fibrocartilage thicker along the lateral margin and thinner on medial margin
Joint capsule
Envelop of tissue that surrounds and encloses the tibiofemoral and patellofemoral joints; Large and completely attached; Lax in resting position (full extension) with several recesses; Stability is provided through passive ligamentous and dynamic musuclar structures.
ACL Sprain
Etiology MOI - athlete decelerates with foot planted and turns in the direction of the planted foot forcing tibia into internal rotation Linked to inability to decelerate valgus and rotational stresses - landing strategies Male versus female.
Bursitis
Etiology: Acute, chronic or recurrent swelling Prepatellar = continued kneeling Infrapatellar = overuse of patellar tendon.
Sinding-Larsen-Johansson Disease
Etiology: An analogous condition involving the patellar tendon and the lower margin of the patella bone, instead of the upper margin of the tibia The condition occurs in active boys and girls aged 9-16 coinciding with periods of growth spurts.
OSD
Etiology: An apophysitis occurring at the tibial tubercle through repeated pulling by tendon. Begins cartilagenous and develops a bony callus, enlarging the tubercle. Resolves with aging.
Joint Contusions
Etiology: Blow to the muscles crossing the joint (vastus medialis).
Acute Patella Subluxation or Dislocation
Etiology: Deceleration with simultaneous cutting in opposite direction (valgus force at knee) Quad pulls the patella out of alignment Some may be predisposed to injury Repetitive subluxation will impose stress to medial restraints Commonly seen in female athletes.
Patellar Fracture
Etiology: Direct, indirect trauma (severe pull of tendon) Forcible contraction, falling, jumping or running.
Patellar Tendinitis
Etiology: Jumping or kicking - placing tremendous stress and strain on patellar or quadriceps tendon Sudden or repetitive extension may lead to inflammatory process.
PCL Sprain
Etiology: Most at risk during 90° of flexion (falling on bent knee) Can also be damaged as a result of a rotational force.
IT Band Friction Syndrome
Etiology: Repetitive/overuse conditions attributed to mal-alignment and structural asymmetries (pronation, leg length discrepancy, lateral pelvic tilt, and genu varum, tight gluteal or quadriceps muscles). Result of repeated knee flexion and extension.
LCL sprain
Etiology: Result of a varus force, generally with the tibia internally rotated Direct blow is rare.
MCL Sprain
Etiology: Result of severe blow or outward twist - valgus force.
Chondromalacia Patella
Etiology: Softening and deterioration of the articular cartilage Possible abnormal patellar tracking due to genu valgum, external tibial torsion, foot pronation, femoral anteversion, patella alta, shallow femoral groove, increased Q-angle, laxity of quad tendon.
ACL Sprain
Extrinsic factors may include- Conditioning, skill acquisition, playing style, equipment, preparation time Also involves damage to other structures including Medial meniscus, joint capsule, MCL.
Bursae
Fills interosseous voids; Highly innervated by articular mechanoreceptors (nociocepters)
Q-angle
Formed by the line of pull of the quads tendon on the patella and the line of pull of the patellar tendon on the tibial tubercle
Menisci
Function: Deepens articulation, filling the gaps which occur during knee motion; Increases contact between the condyles, increasing the load transmission over a greater % of the surface Aids in lubrication and nutrition of the joint
Menisci
Function: Reduces friction Shock absorption Prevents knee hyperextension
Isokinetics
Functioning; movement
Patella
Functions: aids extensor mechanism, protects knee's anterior surface
Apley's Compression Test
Hard downward pressure is applied with rotation Pain indicates a meniscal injury (tear)
2.5
How many mm does a normal ACL undergo in full ROM?
1.5
How many times larger is the PCL than the ACL?
MCL
In midrange the posterior fibers are taut In complete flexion the posterior fibers become taut Primary function is to prevent valgus and external rotating forces.
IT Band friction syndrome
Inflammation of the IT band resulting from varus stresses on the knee; commonly occurs in cyclists and runners
LCL Sprain
Injured from a direct varus force
MCL Sprain
Injured from a valgus force
Cruciate ligaments
Intracapsular and named according to their tibial attachment
Patellar Tendinitis
Jumper's or Kicker's knee
Quads femoris
Knee extension; Rectus femoris (femoral n.) also flexes the hip, especially when the knee is flexed; VMO guides the patella medially during extension.
Hamstrings
Knee flexion and hip extension Decrease the shear force that stresses the ACL when the knee is flexed beyond 20 Biceps femoris also ER tibia Semi-ten & mem IR tibia Popliteus assists PCL in preventing posterior displacement of the tibia on the femur.
Suprapatellar bursa
Largest bursa in the body; between femur and quad femoris tendon and reduces friction between 2 structures
Patella
Largest sesamoid- located in quads tendon
Subpopliteal bursa
Lies between the lateral condyle of the femur and popliteal muscle
Semimebranosus bursa
Lies between the medial head of the gastrocnemius and semimembranosus tendons
Patella
Location: sits in the trochlear groove of the femur; in extension, medial/lateral borders are palpable
ACL
MOI Sudden change in direction Hyperextension of the knee Stopping suddenly Deceleration while running Landing awkwardly from a jump Direct collisions
Sinding-Larsen-Johansson Disease & OSD
Managemen: Conservative Reduce stressful activity until union occurs (6-12 months) Padding may be necessary for protection Possible casting, ice before and after activity Isometrics
IT Band Friction Syndrome
Management Correction of mal-alignments. Ice before and after activity, proper warm-up and stretching; NSAID's. Avoidance of aggravating activities
Bursitis
Management Eliminate cause, RICE and NSAID's Aspiration and steroid injection if chronic.
Joint Contusions
Management RICE initially and continue if swelling persists Gradual progression to normal activity following return of ROM If swelling does not resolve within a week a chronic condition (synovitis or bursitis) may exist requiring more rest.
ACL Sprain
Management RICE; use of crutches Arthroscopy may be necessary to determine extent of injury Could lead to major instability in incidence of high performance, without surgery joint degeneration may result Age and activity may factor into surgical option Surgery may involve joint reconstruction with grafts (tendon), transplantation of external structures Will require brief hospital stay (maybe) and 3-5 wks of bracing Also requires 4-6 months of rehab
Patellar Tendinitis
Management: Avoid aggravating activities Ice, rest, NSAID's Exercise Patellar tendon bracing Transverse friction massage
Chondromalacia Patella
Management: Conservative measures RICE, NSAID's, isometrics for strengthening Avoid aggravating activities Surgical possibilities
LCL Sprain
Management: Grade I and II injuries can usually be treated nonoperatively Knee bracing with the knee locked in full extension is advised Full WB can be performed with the knee brace in place. The patient should perform knee ROM exercises in the prone position only. After 4-6 weeks, patients may return to sport-specific therapy, only if strength and range of motion are comparable to the uninjured side Grade III tears of the LCL involve disruption of the posterolateral corner (PLC) and are best treated with surgical intervention to prevent instability.
Meniscus injuries
Management: Immediate care = PRICE If the knee is not locked, but indications of a tear are present further diagnostic testing may be required Treatment should follow that of MCL injury If locking occurs, anesthesia may be necessary to unlock the joint with possible arthroscopic surgery follow-up With surgery all efforts are made to preserve the meniscus - with full healing being dependent on location Torn meniscus may be repaired using sutures.
Acute Patella Subluxation or Dislocation
Management: Immobilize and refer to physician for reduction Ice around the joint Following reduction, immobilization for up to 4 wks with use of crutches After immobilization period, horseshoe pad with elastic wrap should be used to support patella Muscle rehab focusing on muscle around the knee, thigh and hip are key (SLR's are optimal for the knee).
PCL Sprain
Management: RICE Non-operative rehab of grade I, II injuries should focus on quad strength Surgical versus non-operative Requires a post-operative brace and progressing from WBAT to PWB for 1-6 wks ROM and strengthening after 6 wks, increasing activities as time progresses
MCL Sprain
Management: RICE for least 24-72 hours Crutches and knee immobilizer (brace) is often necessary Move from isometrics and SLR exercises to bicycle riding and isokinetics RTP when all areas (ROM, strength, etc) have returned to normal Continued bracing may be required.
Patellar Fracture
Management: X-ray necessary for confirmation of findings RICE and splinting if fracture suspected Refer and immobilize for 2-3 months
Chondromalacia
May be due to abnormal patellar tracking
Distal knee
Medial plateau is 50% larger to accommodate a longer medial femoral condyle
Medial meniscus
More prone to disruption through torsional and valgus forces
Meniscus injuries
Most common MOI is rotary force with knee flexed or extended while WB
Isometrics
Not functioning; no movement
Lateral meniscus
O-shaped; Smaller in diameter, thicker in periphery, and wider in body; more mobile
Jumper's knee
Patellar or quads tendinitis
friction
Pes anserine bursitis is usually caused by...
Bursitis
Presents with cardinal signs of inflammation. Swelling in popliteal fossa may indicate a Baker's cyst
Joint Contusions
Prevention: Padding for protection.
ACL
Prevents anterior displacement of the tibia on the femur
PCL
Primary stabilizer resisting posterior displacement of the tibia on a FIXED femur; Acts as a drag during the gliding phase of motion.
13-14
Range of Q angle in men
17-18
Range of Q angle in women
Lachman's Drawer Test
Reduces hamstring involvement At 30° of flexion an attempt is made to translate the tibia anteriorly on the femur A positive test indicates damage to the ACL.
LCL
Round pencil like cord ≈ 5 cm long; Passes from the lateral femoral condyle to the head of the anterior fibula; Not part of the joint capsule; L. is separated from the lateral meniscus by a small fat pad Taut when the knee is in extension and relaxed in knee flexion.
Patellar Fracture
Signs and Symptoms: Hemorrhaging and joint effusion with localized swelling Indirect fractures may cause capsular tearing, separation of bone fragments and possible quadriceps tendon tearing Little bone separation with direct injury.
Joint Contusions
Signs and Symptoms: Present as knee sprain Severe pain, loss of movement and signs of acute inflammation Swelling, discoloration.
Fat pad contusion
Signs and symptoms involving the knee that include catching, giving way, palpable pain on either side of the patellar tendon and extreme pain on forced extension suggest...
Joint capsule
Soft tissue structures divided into 4 regions; lined on the interior by a synovial membrane and externally by various ligamentous and muscular structures to help stabilize the joint
MCL
Strong flat band attaching from the adductor tubercle (femur) to the medial surface of the tibia.
MCL
Superficial layer of this extends the length of the l. and passes deep to the pes anserine before inserting on the tibia.
MCL
Taut in complete extension with tautness in the anterior fibers.
Chondromalacia
The presence of generalized anterior knee pain and crepitus in activities such as walking up and down stairs are symptoms associated with...
Prepatellar; deep infrapatellar
The two bursae of the knee that have the highest incidence of irritation in sports are...
PCL
Tibia and lateral meniscus crossing upward, forward, and inward to a fan-shaped line of attachment on the anterior aspect of the medial femoral condyle.
Distal knee
Tibial plateau separated by the intercondylar eminences
Menisci
Two oval-shaped, semilunar fibrocartilages that deepen the facets of the tibia and provide cushion for stresses on the joint
Functional brace
Used S/P injuryCan be custom molded and designed to control rotational forces and tibial translation.
Prophylactic knee brace
Used to prevent-reduce severity of knee injuries; Provides a degree of support to unstable knee.
Lachman's Test
Used to test the integrity of the ACL
Varus stress test
Used to test the integrity of the LCL
Apley's Compression Test
Used to test the integrity of the LCL and MCL
Valgus stress test
Used to test the integrity of the MCL
Menisci
Very narrow vascular zone along the outer rim and an avascular zone formed by the inner rim
Flexion; extension
What are the two principle movements of the knee?
Prepatellar bursitis
may be localized swelling above knee that is ballotable.
Medial meniscus
more commonly injured due to ligamentous attachments and decreased mobility.
