Bow legs, tibial and femoral intra articular fractures lead to medial compartment arthritis. Knock knees lead to lateral compartment arthritis.
Pain is one sided. A squat test will confrm the localisation of pain to the inner or outer half. Tenderness is also in the same half while the other side is normal. Standing x rays are diagnostic.
Antero medial wear in medial compartment arthritis
A depression is seen in the medial tibial plateau as seen in the specimen
Uni condylar replacement or osteotomy are the surgical alternatives in the young patient. A high tibial osteotomy is indicated for active males while a Unicondylar knee replacement is more suitable for a sedentary lady. Quality of pain relief is better with a replacement than an osteotomy.