A Prospective Randomised Control Trial to Compare Clinical and Radiological Outcomes of the Press-Fit Condylar All-Polyethylene Tibial Component With Metal-Backed Tibial Component Implant, in Patients Aged 75 Years or Over

Total knee arthroplasty (TKA) is one of the most commonly performed orthopaedic procedures. Approximately 84,000 knee replacement procedures were recorded in the UK in 2012. The main goal of TKA is to relieve the disabling pain of arthritic disease.

Patient satisfaction following TKA is related to quick recovery and return to daily activities. This can be dependent on the design of the implant used in the knee. Improvements in implant design and surgical technique mean many modern designs offer implant survival rates beyond 10 - 15 years.

As cost pressure increases in the NHS the unit cost of implants is now being scrutinised, particularly with regard to cost effectiveness. The Press-Fit Condylar (PFC) Sigma implant can be used with either a conventional metal backed or alternatively an all polyethylene tibial component (part fitted to the shin bone), the latter considerably cheaper to manufacture. Four small prospective randomised trials and one large regional registry study with long follow up support the safe use of all polyethylene tibial components in TKA. The investigators will therefore undertake a prospective randomised controlled trial comparing the results of all polyethylene tibial components with those of conventional metal backed tibial components in patients aged 75 or over, comparing both clinical outcome and radiological survivorship.

The type of knee replacement used for each patient (metal-backed or polyethylene) will be chosen at random once a patient has agreed to take part in the study.

Data will be collected by means of follow-up appointments and questionnaires and clinical tests both before the operation 1 year, 2 years and 5 years postoperatively. This will allow us to see how both types of knee replacement perform over time and if one performs better than the other in terms of patients movement, pain and functional activities.