A 35-year-old man was seen with pain in the back of the knee. MRI showed a mass in the anterior cruciate ligament. Biopsy indicated mucoid degeneration. Arthroscopic resection of the ligament was carried out, with relief of symptoms.

Total knee arthroplasty (TKR) using a medial capsular approach gives worse results in arthritic knees with valgus deformity than in those in varus, usually because of swelling, poor wound healing and stiffness, instability, recurrent valgus deformity and poor patellar tracking.

A technique for replacement TKR of valgus knees using a lateral capsular approach was described several years ago, but was not routinely adopted because of the difficulties with and complexity of the procedure which included deliberate elevation of the tibial tubercle. In order to avoid this we have modified and simplified the procedure. Our preliminary results suggest that this lateral approach is safe and may give a better outcome than that through the medial capsule for the replacement of valgus knees.