| Ruptured anterior cruciate ligament | • Sport injury • Mechanism: high twisting force applied to a bent knee • Typically presents with: loud crack, pain and RAPID joint swelling (haemoarthrosis) • Poor healing • Management: intense physiotherapy or surgery | | --- | --- | | Ruptured posterior cruciate ligament | • Mechanism: hyperextension injuries • Tibia lies back on the femur • Paradoxical anterior draw test | | Rupture of medial collateral ligament | • Mechanism: leg forced into valgus via force outside the leg • Knee unstable when put into valgus position | | Menisceal tear | • Rotational sporting injuries • Delayed knee swelling • Joint locking (Patient may develop skills to 'unlock' the knee • Recurrent episodes of pain and effusions are common, often following minor trauma | | Chondromalacia patellae | • Teenage girls, following an injury to knee e.g. Dislocation patella • Typical history of pain on going downstairs or at rest • Tenderness, quadriceps wasting | | Dislocation of the patella | • Most commonly occurs as a traumatic primary event, either through direct trauma or through severe contraction of quadriceps with knee stretched in valgus and external rotation • Genu valgum, tibial torsion and high riding patella are risk factors • Skyline x-ray views of patella are required, although displaced patella may be clinically obvious • An osteochondral fracture is present in 5% • The condition has a 20% recurrence rate | | Fractured patella | • 2 types:i. Direct blow to patella causing undisplaced fragmentsii. Avulsion fracture | | Tibial plateau fracture | • Occur in the elderly (or following significant trauma in young) • Mechanism: knee forced into valgus or varus, but the knee fractures before the ligaments rupture • Varus injury affects medial plateau and if valgus injury, lateral plateau depressed fracture occurs • Classified using the Schatzker system (see below) |
| Type | Anatomical description | Features |
|---|---|---|
| 1 | Vertical split of lateral condyle | Fracture through dense bone, usually in the young. It may be virtually undisplaced, or the condylar fragment may be pushed inferiorly and tilted |
| 2 | Vertical split of the lateral condyle combined with an adjacent load bearing part of the condyle | The wedge fragment (which may be of variable size), is displaced laterally; the joint is widened. Untreated, a valgus deformity may develop |
| 3 | Depression of the articular surface with intact condylar rim | The split does not extend to the edge of the plateau. Depressed fragments may be firmly embedded in subchondral bone, the joint is stable |
| 4 | Fragment of the medial tibial condyle | Two injuries are seen in this category; (1) a depressed fracture of osteoporotic bone in the elderly. (2) a high energy fracture resulting in a condylar split that runs from the intercondylar eminence to the medial cortex. Associated ligamentous injury may be severe |
| 5 | Fracture of both condyles | Both condyles fractured but the column of the metaphysis remains in continuity with the tibial shaft |
| 6 | Combined condylar and subcondylar fractures | High energy fracture with marked comminution |