Pain which is localized to either the medial (inside) or lateral (outside) aspect of the joint is usually due to pathology of either the articular (joint) cartilage or the medial or lateral meniscus. Patients may experience a lack of full knee range of motion, difficulty with squatting, or have occasional catching or grinding with activities.

The portions of the physical examination which we utilize to assess for these areas of pathology include assessment of the patient's range of motion, assessment of pain with maximal knee flexion, and assessment for joint line pain or crepitation during a forced varus or valgus stress test. In the later test, the examiner needs to put their fingers directly over the joint line to assess for any joint line pathology.

Other sources of joint line pain include localized partial or complete tears of the joint capsule, loose bodies, osteochondritis desicanns, avascular necrosis, or other potential sources of joint line pain.

Standing AP and lateral radiographs are useful to help determine if there is any associated joint line narrowing, ostephytes (bone spurs), sclerosis of the supporting bone, or squaring of the condyles which may indicate some underlying arthritis. An intercondylar notch view may be useful to help determine the presence of loose bodies or osteochondritis desiccans. The use of an MRI scan may also be useful to help determine the status of the articular cartilage or meniscal tears.