Inclusion Criteria:  Patients having medial uni-compartmental knee arthroplasty Functionally intact anterior cruciate ligament Able to give informed consent Able to return to GJNH for follow-up BMI under 40  Exclusion Criteria:  Inflammatory joint disease e.g. rheumatoid arthritis Previous hip procedure in the last twelve months Previous knee surgery other than arthroscopy and medial menisectomy Previous ankle surgery Symptomatic foot, hip or spinal pathology Any medical condition limiting normal ambulation e.g. stroke, Charcot-Marie-Tooth disease, severe lymphedema, advanced cardiac disease