Understanding the Complexities of Knee Anatomy

1. The Knee

2. ANATOMY

3. The Knee • Bones (4) • Femur • Tibia • Fibula • Patella

4. Patella • Sesamoid bone – sits inside the quadriceps/patellar tendon • Patellar tendon attaches to the tibial tuberosity • Patella rides in a groove on the femur

5. The Knee • Joints (2) • Femur and tibia • Motions: flexion and extension • Patellofemoral • Patella sits on the femur in quadriceps tendon

6. Ligaments • Cruciates (2) • Short, strong ligaments inside the knee joint • Cross each other and form an ‘x’ • Cruciate means cross • Named for where they attach on the tibia • Functions • Provide anterior and posterior stability • Prevent rotation at knee

7. Ligaments • Cruciates • Anterior Cruciate Ligament (ACL) • Prevents anterior movement of tibia on femur

8. Ligaments • Cruciates • Posterior Cruciate Ligament (PCL) • Twice as strong as the ACL • Prevents posterior movement of the tibia on the femur

9. Ligaments • Collaterals • On sides of knee • Give side to side stability

10. Ligaments • Collaterals • Medial Collateral Ligament (MCL) • Goes from the femur to the tibia • Prevents valgus stress • Valgus stress: pushing knee from outside in

11. Ligaments • Collaterals • Lateral Collateral Ligament (LCL) • Goes from femur to the head of the fibula • Prevents varus stress • Varus Stress: Knee pushed from inside out

12. Meniscus • “Cartilage” of the knee • Sit on the tibia • Functions: • Deepens socket for the femur • Gives stability to the knee • Shock absorption

13. Meniscus • Medial • Larger and ‘c’ shaped • More firmly fixed to the tibia • Attached to tibia, MCL, and joint capsule • Lateral • Oval shaped • More freely movable

14. Muscles • Quadriceps femoris (Quad) • Four muscles on the anterior thigh • Rectus Femoris • Vastus Medialis • Vastus Intermedius • Vastus Lateralis • Function is to straighten/extend the knee • Patella sits inside the tendon that is formed by these muscles

15. Muscles • Hamstrings • Three muscles on the posterior thigh • Biceps Femoris • Semitendinosus • Semimembranosus • Function is to flex/bend the knee • Also function to extend the hip

16. INJURIES

17. MCL Sprain • Cause • Blow to the lateral side of the knee • Rotation to knee • Signs and Symptoms • MCL is tender to touch • Hurts to have knee totally straight • Positive Valgus stress test • Will “give out” if 2nd or 3rd degree • Treatment • RICE immediately • Immobilizer/brace for 2-6 weeks

18. LCL Sprain • Cause • Injured by a blow to the medial side of the knee • Not a very common injury • Signs and Symptoms • Pain and tenderness over LCL • Positive Varus Stress test • Treatment • RICE immediately • Immobilizer/brace for 2-6 weeks

19. PCL Sprain • Injured by: • Blow forcing tibia back • Leg is bent and it is hit on tibial tuberosity • Hyperextension • Signs and Symptoms • Feel and hear pop in the back of the knee • Positive Posterior Drawer Test • Care • RICE immediately and rehab • Some athletes can participate without a PCL

20. ACL Sprain • Causes • Plant and cut in opposite direction • Hyperextension • Blow to the lateral side • Signs and Symptoms • Feel and hear a pop • Immediate swelling • Significant pain and then pain can subside • Positive Lachman’s and Anterior Drawer Test • Feels like it will give out if standing on it • Treatment • RICE immediately, Crutches • Needs surgery to repair – out 6 months

21. Meniscus Tear • Injured when they get trapped/pinched between the bones • Medial Meniscus injured more often than Lateral Mensicus • Cause • Planting foot and cutting in opposite direction, knee is flexed • Sign and Symptoms • Symptoms can come about 48-72 hours later • Swelling, giving out, knee locks up, clicking • Pain with squatting • Treatment • RICE • If locked, to MD right away • Needs Arthroscopic surgery

22. The Unhappy Triad • Injury to the ACL, MCL and Medial Meniscus • Injured all at once • Cause: planting foot and cutting/twisting

23. Patellar Tendinitis • Also known as Jumper’s Knee • Cause • Running and jumping sports • Poor flexibility • Signs and Symptoms • Sorest at warm-up and cool down • May have crepitus • Tender over patellar tendon • Treatment • Rest – decrease pounding activity • Anti-inflammatory meds • Ice/Ice Massage • Heat • Patellar Tendon Strap

24. Osgood-Schlatter • Insertion of the patellar tendon on the tibial tuberosity gets stressed and pulls away from its insertion site • Cause • From repeated jumping • Common in adolescents due to growth spurt and inflexibility • Signs and Symptoms • Pain will be right on the tibial tuberosity • Tibial tuberosity will become much more prominent • Treatment • Much the same as patellar tendonitis • Modify activity as pain persists

25. Dislocation/Subluxation of Patella • Dislocated patella • Goes out and stays out • Victim will be found with knee bent – patella will be on lateral side of knee • Extending the knee will reduce the patella • Subluxed patella • Dislocates and reduces itself quickly • More common • Signs: History of patella problems, sore over the medial aspect of the patella

26. Dislocation/Subluxation of Patella • Cause • Due to quad contracting and/or twisting of the knee • Once it happens, it is more likely to happen again • More likely to happen if you are • Female • Have a weak vastus medialis • Treatment • Referral to doctor/ER • RICE immediately • Will usually require rehab, surgery and/or immobilization

27. Chondromalacia • Cause • Degenerative process where the articular cartilage under the patella softens and then wears away • Patella may not track well in the groove • Poor flexibility • Squatting activities • Signs and Symptoms • Pain and grinding sensation under the patella • Aching pain after activity • Treatment • Ice • Increase flexibility of leg muscles • May have to decrease activity while inflamed.

28. Pre-Patellar Bursitis • Cause • Direct hit to knee • Kneeling • Signs and Symptoms • Increased swelling right on top of knee • Treatment • Ice • Compression • Eliminate the cause