Pa of knee most commonly involved in osteoahritis: March 2009
**Core Concept**
The question is testing the understanding of the anatomy and pathophysiology of osteoarthritis (OA), specifically the involvement of the knee joint. Osteoarthritis is a degenerative joint disease characterized by the breakdown of cartilage and underlying bone in the joints.
**Why the Correct Answer is Right**
The medial compartment of the knee is most commonly involved in osteoarthritis due to the higher stresses and loads transmitted through this compartment. The medial compartment is subjected to increased valgus stress, which can lead to cartilage wear and tear. The medial meniscus and the medial collateral ligament also contribute to the increased stress in this compartment.
**Why Each Wrong Option is Incorrect**
* **Option A:** The lateral compartment is less commonly involved in osteoarthritis due to lower stresses and loads transmitted through this compartment.
* **Option B:** The patellofemoral joint is involved in osteoarthritis, but it is not the most commonly affected area of the knee joint.
* **Option D:** The patellofemoral joint is not a separate compartment of the knee joint.
**Clinical Pearl / High-Yield Fact**
In patients with osteoarthritis of the knee, valgus stress can exacerbate the condition, and a medial bracing device may be used to redistribute the load and alleviate symptoms.
**Correct Answer:** A. The medial compartment of the knee is the most commonly involved part in osteoarthritis.