Knee joint

it concentrates mainly on the movements of the knee joint and locking and unlocking of knee joint. it is more easy and simple and complete

1. MOVEMENTS LOCKING AND UNLOCKING OF THE KNEE JOINT By M.Aravind MBBS Ist year DSMCH Perambalur MOVEMENTS LOCKING AND UNLOCKING OF THE KNEE JOINT M.ARAVIND MBBS I YEAR DSMCH

2. KNEE JOINT It is the largest joint of the body It is formed between lower end of femur, upper end of tibia and patella The condyles of femur The patella The condyles of tibia ARTICULAR SURFACES

3. Type A modified hinge type of synovial joint (as some degree of rotation takes place during locking and unlocking of the joint. Weak joint Articular surfaces are not congruent Tibial condyles are shallow Femoropatellar articular surfaces are shallow Outward angulation between the long axis of leg and knee

4. Strength of the knee joint Cruciate ligaments maintain anteroposterior stability Collateral ligaments maintain side to side stability Capsule is strengthened by Anterior- medial and lateral patellar retinacula Posterior - oblique popliteal ligament Medial - expansions from tendons of sartorius and semitendinosus Lateral- illiotibial tract

5. Complexity of the joint The joint consists of two parts Condylar synovial joint- between two femoral condyles and tibial condyles Saddle joint- between the lower end of femur and patella

6. Movements at the knee joint Flexion and extension Medial and lateral rotation Chief movements Takes place in upper compartment of the joint, above the menisci Takes place around transverse axis Small range of movements Takes place in the lower compartment of the joint, below the menisci Takes place around vertical axis

7. During different phases of movements of knee different portions of patella articulate with the femur. Extension- lower pair of articular facets Beginning of flexion- middle pair Midflexion- upper pair Full flexion- medial strip ROTATORY MOVEMENTS

8. Muscles producing movements at the knee joint EXTENSION - Quadriceps femoris FLEXION- Biceps femoris, semimembranosus, semitendinosus MEDIAL ROTATION OF FLEXED LEG- Popliteus, semimembranosus, semitendinosus LATERAL ROTATION OF FLEXED LEG- Biceps femoris LOCKING- Vastus medialis UNLOCKING- Popliteus

9. Have you ever noticed that You stand for a long time without much muscular effect. How is it possible? It is due to locking mechanism of knee joint

10. LOCKING OF KNEE JOINT The anteroposterior diameter of the lateral femoral condyle is less than that of the medial condyle. Therefore the lateral condylar surface is fully used up It serves as the axis around which the medial condyle rotates medially so that the remaining part is used up. All the ligaments of the knee joint are taut.

11. Locking Unlocking During last 30 degrees of extension Medial rotation of femur Helped by quadriceps femoris (mainly vastus medialis ) As standing at attention The ligaments are taut During initial stages of flexion Lateral rotation of femur Helped by popliteus As standing at ease The ligaments are relaxed

12. Accessory or passive movements performed in a partially flexed knee A wider range of rotation Anteroposterior gliding of the tibia on the femur Some adduction and abduction Some seperation of the tibia from the femur

13. CLINICAL ANATOMY OSTEOARTHIRITIS CONDITION- Degeneration of the articular surfaces CAUSES- Ageing,congenital deformity, fracture around the knee joint DEFORMITY - Limited movements, pain BAKER’S CYST- Synovial membrane protrudes through a hole in the posterior surface of the knee joint, central swelling SYMPTOMS : Knee pain, stiffness, swelling

14. KNEE REPLACEMENT TREATMENT In the past such patients had to depend on heavy doses of analgesics to relieve pain Now the entire joint can be replaced using artificial materials giving long lasting relief to many

15. DEFORMITIES OF THE KNEE GENUM VALGUM OR KNOCK KNEE GENUM VARUM OR BOW KNEE LEG MAY BE ABNORMALLY ABDUCTED LEG MAY BE ABNORMALLY ADDUCTED CAUSES RICKETS POSTURE CONGENITAL ABNORMALITY

16. DISLOCATION OF THE KNEE JOINT Rare Results in damage to Poplital artery Tibial nerve or Common peroneal nerve

17. INJURIES IN THE REGION OF KNEE JOINT TRAUMATIC SYNOVITIS- joint cavity filled with serous fluid HAEMARTHROSIS - joint filled with blood RHEUMATOID ARTHIRITIS- autoimmune condition GOUT- deposition of sodium urate crystals PSEUDOGOUT- deposition of calcium phosphate crystals SEPTIC ARTHIRITIS- bacterial infection

18. KNEE TESTS ARTHROSCOPY Arthroscopy involves the introduction of a lighted instrument into the synovial cavityof the knee joint through a small incision. The technique permits the direct visualization of structures such as the cruciate ligaments and the menisci for diagnostic purposes. Parts of torn menisci (ligaments) and other parts of loose tissue can be removed KNEE X-RAY MAGNETIC RESONANCE IMAGING- ligamental and meniscal injury

19. PNEUMOARTHROGRAPHY Air can be injected into the synovial cavity of the knee joint so that the soft tissues can be studied. This technique is based on the fact that air is less radiopaque than structures the medial and lateral menisci, so their outline can be visualized on a radiograph

20. CONDYLES OF TIBIA FIBULA PATELLA CONDYLES OF FEMUR ARTICULATING SURFACES SUMMARY MOVEMENTS LOCKING AND UNLOCKING OSTEOARTHIRITIS GENUS VARUM AND VALGUM

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