Bone Joint J. 2016 Oct; 98-B(10 Supple B): 22–27.

A survival analysis of 1084 knees of the Oxford unicompartmental knee arthroplasty

N. Bottomley, DPhil (Oxon), FRCS (Tr&Orth), Consultant Orthopaedic Surgeon,1 L. D. Jones, DPhil (Oxon), FRCS (Tr&Orth), Orthopaedic Registrar,1 R. Rout, DPhil (Oxon), FRCS (Tr&Orth), Orthopaedic Registrar,1 A. Alvand, BSc(Hons), DPhil (Oxon), FRCS (Tr&Orth), Clinical Lecturer,1 I. Rombach, PhD, Statistician,1 T. Evans, MBBS, MSc, MRCS, Core Surgical Trainee,1 W. F. M. Jackson, BSc(Hons), FRCS(Orth), Consultant Orthopaedic Surgeon,1 D. J. Beard, DPhil (Oxon), Professor of Musculoskeletal Sciences,1 and A. J. Price, DPhil (Oxon), FRCS (Tr&Orth), Professor of Orthopaedic Surgery and Consultant Orthopaedic Surgeon1

Knee

Aims

The aim of this to study was to compare the previously unreported long-term survival outcome of the Oxford medial unicompartmental knee arthroplasty (UKA) performed by trainee surgeons and consultants.

Patients and Methods

We therefore identified a previously unreported cohort of 1084 knees in 947 patients who had a UKA inserted for anteromedial knee arthritis by consultants and surgeons in training, at a tertiary arthroplasty centre and performed survival analysis on the group with revision as the endpoint.

Results

The ten-year cumulative survival rate for revision or exchange of any part of the prosthetic components was 93.2% (95% confidence interval (CI) 86.1 to 100, number at risk 45). Consultant surgeons had a nine-year cumulative survival rate of 93.9% (95% CI 90.2 to 97.6, number at risk 16). Trainee surgeons had a cumulative nine-year survival rate of 93.0% (95% CI 90.3 to 95.7, number at risk 35). Although there was no differences in implant survival between consultants and trainees (p = 0.30), there was a difference in failure pattern whereby all re-operations performed for bearing dislocation (n = 7), occurred in the trainee group. This accounted for 0.6% of the entire cohort and 15% of the re-operations.

Conclusion

This is the largest single series of the Oxford UKA ever reported and demonstrates that good results can be achieved by a heterogeneous group of surgeons, including trainees, if performed within a high-volume centre with considerable experience with the procedure.

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