Triple deformity of knee includes all EXCEPT:
**Core Concept**
The triple deformity of the knee is a characteristic alignment abnormality seen in patients with severe knee disorders, particularly those with advanced osteoarthritis or rheumatoid arthritis. It involves a combination of flexion, valgus, and posterior subluxation of the tibia relative to the femur, leading to a characteristic abnormal gait and mobility issues.
**Why the Correct Answer is Right**
The triple deformity of the knee is a complex alignment abnormality resulting from the interplay of multiple factors, including joint degeneration, ligamentous laxity, and muscle weakness. The flexion component arises from the contraction of the hamstrings and quadriceps, leading to an abnormal forward displacement of the tibia. The valgus component is caused by the weakening of the medial collateral ligament and the lateral stabilizing structures, resulting in an outward displacement of the tibia. The posterior subluxation is a result of the posterior cruciate ligament (PCL) insufficiency, which allows the tibia to slide posteriorly relative to the femur.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because it may not be a component of the triple deformity of the knee, and the specific deformity associated with this option is not clearly defined in the context of the triple deformity.
**Option B:** This option is incorrect because it may be a component of the triple deformity of the knee, but it is not the only option listed and may not be the best choice as the exception.
**Option C:** This option is incorrect because it may be a characteristic feature of the triple deformity of the knee and is consistent with the description of the deformity.
**Clinical Pearl / High-Yield Fact**
It's essential to recognize the triple deformity of the knee as a sign of advanced joint disease, which may require surgical intervention to alleviate pain and improve mobility.
**Correct Answer:** C.