Five-year experience of cementless Oxford unicompartmental knee replacement

Purpose: Cementless unicompartmental knee replacement (UKR) was introduced to address some the problems that can occur following cemented UKR. The aim of this study was to report the five year experience of the first 512 medial cementless Oxford UKR implanted by two surgeons for the recommended indications. Methods: The first consecutive 512 cementless Phase 3 Oxford cemented UKRs implanted by two surgeons for the recommended indications between June 2004 and October 2013 were prospectively identified and followed up independently. All the procedures were carried out through a minimally invasive approach without eversion or dislocation of the patella. Patients were assessed clinically preoperatively and at one, two, five, seven and ten years after surgery with functional outcome scores and radiographs. Results: There were 8 reoperations of which 6 were revisions giving a 5 year survival of 98% (95% CI 94 - 100%). At a mean follow-up of 3.4 years (1.0 to 10.2) the mean OKS was 43 (SD 7), AKSS (objective) was 81 (SD 13) and AKSS (functional) was 86 (SD 17). The first 120 cases had a minimum follow up of five years (mean 5.9; range 5 - 10.2). In these patients the mean OKS was 41 (SD 8), AKSS (objective) was 81 (SD 14) and AKSS (functional) was 82 (SD 18). There were no femoral radiolucencies, and no complete tibial radiolucencies. 11% of tibial components had partial radiolucent lines; the remaining 89% had no radiolucencies. Conclusion: The clinical results are as good as or better than those previously reported for cemented fixation. The radiographic results are better with secure bony attachment to the implants in every case