Introduction: Polyethylene wear of the prosthetic knee tibial component is currently the main cause of medium and long term failure of total knee arthroplasty. The use of a mobile bearing knee prosthesis is intended to decrease the rate polyethylene wear and therefore delay medium and long term failure. We present our five year clinical results of a mobile bearing knee prosthesis.

Material and methods: 150 mobile bearing knee arthroplasties implanted between 1993 and 1996 in our institution were followed. 15 knees were lost to follow up. All knees followed up were operated on for osteoarthritis.

The British Orthopaedic Association knee function score was used to access the clinical results and the Knee Society Radiographic evaluation was used for radiological evaluation.

Results: 33% of patients achieved an excellent result, 52% a good result, and only 3% were not satisfied with the end result.

Flexion was greater than 90 degrees in 97% of the patients.

Three knees required re-surgery, 1 for deep sepsis, 1 for patello femoral problems and 1 for a fractured polyethylene component.

No knee required revision for polyethylene were or loosening.

Conclusions: Our mid term results are comparable to those of other prosthesis both mobile and fixed bearing knees as far as revision and radiological and functional scores are concerned. We noted that patient satisfaction in the face of good radiological and functional scores is less than would be expected.