Investigator Initiated Depuy Replacement knee In-Vivo Evaluation Study

INTERVENTION: A total of 40 patients will be recruited to the study. These patients will undergo a range of baseline evaluations as appropriate to their presenting condition. These would include: 1. A routine musculoskeletal clinical examination (including assessment of presenting symptoms and clinical musculoskeletal functional tests) 2. Completion of relevant patient reported outcome instruments (36‐item short form health survey [SF‐36], Oxford knee score, Knee Injury and Osteoarthritis Outcome Score [KOOS], Knee Society Clinical Rating System [KSS]) 3. Knee joint kinematics and kinetics measured using Vicon T series, Oxford Metrics Oxford UK 4. Functional measures to be undertaken include: 4.1. High flexion angle joint function measured using Fastrak electromagnetic motion tracking (Polhemus, USA) 4.2. High demand joint function (Sit to stand and squat) measured using Vicon T series (Oxford Metrics Oxford, UK) A case/control design will be used to compare outcomes following surgery in patients receiving PFC sigma and CR150 implants. Patients will undergo the same range of evaluations as those described above at 3 months, 6 months and 1 year. CONDITION: Osteoarthritis ; Musculoskeletal Diseases ; Osteoarthritis PRIMARY OUTCOME: Maximum knee flexion measured using the Fastrak electromagnetic motion tracking system (Polhemus, USA) SECONDARY OUTCOME: A comparison of high performance activities (sit to stand and squatting) 12 months after surgery INCLUSION CRITERIA: 1. Patients (no age limit, either sex) with osteoarthritis of the knee undergoing unilateral knee replacement at Chapel Allerton Orthopaedic Centre 2. Patients with a functionally normal contralateral knee