Loss of the meniscus decreases contact area, resulting in increased stress on the articular cartilage of the knee. Osteoarthritis frequently develops and sclerotic bone is exposed on the articular surfaces of the joint. In the medial compartment, this process is characterized by loss of articular cartilage and anterior cruciate ligament and medial cruciate ligament laxity in the extension gap, with no corresponding laxity in the flexion gap. This focal articular and ligamentous imbalance may persist for a decade or more. Minimally invasive unicondylar arthroplasty is a low-morbidity procedure that resurfaces the medial compartment and rebalances ligaments while preserving bone for future arthroplasty procedures.