Regional five-year clinical outcomes of 289 consecutive cementless oxford uni-compartmental knee replacements at a non-inventor centre.

INTRODUCTION

Uncemented unicompartmental knee replacement offers a minimally invasive approach, faster rehabilitation and good levels of function, supported by evidence reporting low intra-operative fracture rate and mid-term stability with no implant migration at 5-years. Our aim was to examine the clinical outcomes in 289 consecutive Oxford unicompartmental knee arthroplasties (257 patients), five years post-operatively.

METHODS

A retrospective study of patients treated between 2008 and 2014 in a non-inventor centre by a single surgeon was performed. Patients with anteromedial bone on bone uni-compartmental arthritis were included. Oxford Knee Scores (OKSs) at last follow-up were recorded, intra-operative complications reported with commentary on revision cases.

RESULTS

Mean age of patients was 66 years (SD 9.6, 45-88 years). 122 (42%) patients were female and 135 (58%) were male. Patient in our study were ASA 1 (36%), ASA 2 (62%) and ASA 3 (01%). There were no intra-operative complications, particularly tibia fractures during impaction. The average oxford knee score was 40.1 (n = 232, Range 06 to 48, SD 8.46) at an average 6 years and 3 months from surgery, including revised patients. Six patients had their prosthesis revised within five-years of the index surgery. Five-year cumulative implant survival rate was 97.8% (95% CI 97.62 to 97.98, SE 0.09). Indications for revision were: lateral side wear (n = 1); dislocated spacer (n = 4); instability and spacer subluxation (n = 1). Thirteen patients died within five years of surgery Five-year cumulative survival rate was 94.9% (95% CI 94.87 to 94.925, SE 0.013).

CONCLUSION

The proportion of patients requiring revision at five-years is lower than that generally reported for UKR. These findings add support for the use of the cementless oxford UKR outside the design centre.