The Knee

1. The Knee

2. Basic Anatomy

3. Basic Anatomy • Ligaments • Anterior Cruciate Ligament (ACL) • Prevents femur moving posteriorly during weight bearing • Attaches anterior tibia to lateral femur • Posterior Cruciate Ligament (PCL) • Primary stabilizer & stronger than ACL • Attaches posterior femur to anterior tibia • Medial Collateral Ligament (MCL) • Taut during knee flexion & relaxed in extension • Prevents knee from valgus and external rotating forces • Attaches medial femur & medial tibia • Lateral Collateral Ligament (LCL) • Taut during knee extension & relaxed in flexion • Attaches to the lateral femur & head of fibula

4. Meniscus • Medial meniscus: C-shaped fibrocartilage • Lateral meniscus: O-shaped fibrocartilage • Each meniscus is divided into 3 circumferential zones: • Outer zone = good vascular supply • Middle zone = minimal vascular supply • Innner zone = avascular

5. Knee Injuries

6. Prevention of Knee Injuries • Physical conditioning • Muscles surrounding knee joint must be strong and flexible • Focus on hamstring, erector spinae, groin, quadriceps, gastrocnemius flexibility • Rehabilitation and skill development • Strength, balance and technique - sport specific • Shoe Type • More and shorter cleats

7. MCL sprain Cause: • valgus force (lateral blow) or severe outward twist • Greater injury results from medial sprains vs. lateral sprains

8. S&S: • Grade I = few ligamentous fibers are torn and stretched; joint is stable, little/no swelling, possible joint stiffness & point tenderness, full ROM • Grade II = complete tear of deep cpsular ligament and partial tear of of MCL; slight laxity in full extension, no gross instability; no/little swelling; moderate to severe joint stiffness with inability to fully extend the knee; decrease PROM; medial pain • Grade III = complete loss of medial instability; swelling; immediate severe pain followed by dull ache; loss of motion because effusion and hamstring guarding Care: RICE; crutches; immobilzer; ROM exercises; rehabilitation; hinge brace (grade I, II)

9. LCL sprain Cause: • varus force & internal rotation of the tibia • Less prevalent than MCL

10. S&S: • Grade I = joint is stable, little/no swelling, possible joint stiffness & point tenderness, full ROM • Grade II = slight laxity in full extension, no gross instability; no/little swelling; moderate to severe joint stiffness with inability to fully extend the knee; decrease PROM; lateral pain • Grade III = complete loss of lateral instability; swelling; immediate severe pain followed by dull ache Care: RICE; crutches; immobilzer; ROM exercises;rehab; hinge brace; surgery controversial

11. ACL sprain Cause: foot planted, femur externally rotated S&S: hear/felt “pop”; immediate disability; rapid swelling; intense pain immediately then subsiding Care: RICE; crutches; immobilizer; surgery likely; 3-5 wks in brace; rehab 4-6 months

12. PCL sprain • Called the most important ligament in the knee • Provides central axis for rotation • Provides ~95% restraint of posterior displacement of tibia Cause: most at risk when knee is bent hyperflexed knee with full weight on anterior aspect of knee and foot plantarflexed; rotational force which may affect medial/lateral side of knee S&S: pop in back of knee; tenderness and swelling in back of knee (popliteal fossa); laxity of ligament Care: RICE; Grade 1 & 2 - non-op, rehab focusing on quad strengthening; rehabilitation; controversy over surgery

13. Meniscus injuries Cause: weight bearing combined with rotational stress while extending/flexing knee S&S: may or may not result in effusion gradually over 48-72 hrs; joint line pain and loss of motion; intermittent locking/giving way; pain with squatting Care: RICE; recovery depends on location of tear; not uncommon to return 6-14 days after surgery (menisectomy); repaired meniscus may require immobilization for 5-6 wks, longer recovery

14. Bursitis Cause: acute, chronic, recurrent; prepatellar and deep infrapatellar have highest incidence; prepatellar inflamed from continued kneeling or falling directly on knee; infrapatellar irritated from overuse of patellar tendon S&S: localized swelling; redness; increased temperature; pain due to swelling Care: eliminating cause; rest; swelling; compression; padding; NSAIDs; possible aspiration

15. Iliotibial band friction syndrome (Runners knee) • Overuse condition commonly in runners and cyclists who have genu varum and pronated feet • Irritation develops at the band’s insertion over the lateral femoral condyle causing friciton

16. Cause: overuse that can be attributed to malalignment and structural asymmetries of the foot and lower leg; S&S: tenderness along ITB; little/no swelling; pain increases with activity Care: stretch ITB; massage; foam roller: correction of foot and leg alignment problems; ice

17. Chrondromalacia • softening and deterioration of the articular cartilage on back of patella • Exact cause is unknown • Abnormal patellar tracking due to numerous factors Chondromalacia undergoes 3 stages: • Stage 1 = swelling and softening of articular cartilage • Stage 2 = fissuring of the softened articular cartilage • Stage 3 = deformation of the surface of the articular cartilage caused by fragmentation

18. Chondromalacia S&S: pain anterior knee while walking, running up/down stairs or squatting; recurrent swelling around kneecap; grating sensation when flex/ext knee Care: avoid irritating activities; isometric ex; NSAIDs; neoprene sleeve; possible sx

19. Patellar tendonitis (jumper’s knee) Cause: jumping, running, or kicking repetitively • Sudden or repetitive forceful extension of knee may begin an inflammatory process that will eventually lead to tendon degeneration S&S: tenderness; pain; • 3 stages: • Stage 1 - pain after activity • Stage 2 - pain during and after but functional • Stage 3 - pain during and prolonged after activity; may progress to constant Care: avoid irritating activities; RICE; patellar tendon brace; NSAIDs; transverse friction massage (TFM)

20. Osgood-Schlatter disease Cause: adolescent; repeated pull of patellar tendon at the tibial tubercle; bony callus forms and tubercle enlarges; usually resolves in late teen years S&S: repeated irritation causing swelling; hemorrhage, and gradual degeneration of tibial tubercle; severe pain when kneeling; jumping and running; point tenderness Care:  stressful activities; ice before and after activity; isometric strengthening of quads and hams

21. Patellar dislocation Cause: quad muscle pulls in a straight line and patella pulls laterally creating a force that may sublux/dislocate patella S&S: complete loss of knee function; pain with swelling; obvious deformity; possible fracture Care: ice; referral with a dislocation - spontaneous reduction may occur if athlete is able to straighten knee

22. Osteochondritits Dissecans • A painful condition involving partial or complete separation of a piece of articular cartilage and subchondral bone • Exact cause is unknown • Possible causes = • direct or indirect trauma • skeletal or endocrine abnormalitites • prominent tibial spine or part of patella impinging on medial femoral condyle

23. S&S: achy knee, swells recurrently, may catch or lock, possible atrophy of quadriceps • Care: for children, rest and immobilization; may take as long as 1yr to resolve; surgery = drilling in the area to stimulate healing, pinning loose fragments, or bone grafting (Amare Stoudamire, Greg Oden)