The influence of different sets of surgical instrumentation in Oxford UKA on bearing size and component position

Tilman Walker; Pascal Heinemann; Thomas Bruckner; Marcus R Streit; Stefan Kinkel; Tobias Gotterbarm

doi:10.1007/s00402-017-2702-2

The influence of different sets of surgical instrumentation in Oxford UKA on bearing size and component position

Arch Orthop Trauma Surg. 2017 Jul;137(7):895-902. doi: 10.1007/s00402-017-2702-2. Epub 2017 Apr 24.

Authors

Tilman Walker¹, Pascal Heinemann¹, Thomas Bruckner², Marcus R Streit¹, Stefan Kinkel³, Tobias Gotterbarm⁴

Affiliations

¹ Clinic for Orthopaedics and Trauma Surgery, University of Heidelberg, Schlierbacher Landstrasse 200a, 69118, Heidelberg, Germany.
² Institute of Medical Biometry and Informatics, University of Heidelberg, Im Neuenheimer Feld 130.3, 69120, Heidelberg, Germany.
³ ARCUS Clinic for Orthopaedic Surgery, Rastatter Str. 17-19, 75179, Pforzheim, Germany.
⁴ Clinic for Orthopaedics and Trauma Surgery, University of Heidelberg, Schlierbacher Landstrasse 200a, 69118, Heidelberg, Germany. tobias.gotterbarm@med.uni-heidelberg.de.

PMID: 28439701
DOI: 10.1007/s00402-017-2702-2

Abstract

Introduction: The Oxford unicompartmental knee arthroplasty (OUKA) has been proven to be an effective treatment for anteromedial osteoarthritis of the knee joint. New instrumentation has been introduced to improve the reproducibility of implant positioning and to minimize bone loss during tibial resection (Oxford Microplasty; Zimmer Biomet, Warsaw, Indiana, USA).

Methods: To assess the effect of the new instrumentation, we retrospectively evaluated the postoperative radiographs and surgical records of 300 OUKAs in three consecutive cohorts of patients. The first cohort consists of the first 100 minimal invasive implantations of the OUKA using the conventional phase III instrumentation, the second cohort consists of the 100 most recent minimal invasive OUKA with the conventional phase III instrumentation and the third cohort consists of the first 100 minimal invasive OUKA using the new Oxford Microplasty instrumentation.

Results: Mean bearing thickness was statistically significant and lower in OUKA with use of the updated instrumentation than with the conventional instrumentation (p = 0.01 and p = 0.04). Additionally, statistically significant and more femoral components were aligned within the accepted range of tolerance in both the coronal and the sagittal plane with use of the updated instrumentation compared to the conventional phase III instrumentation in group A (p = 0.029 and p = 0.038) and in the sagittal plane with use of the updated instrumentation compared to the conventional phase III instrumentation in group B (p = 0.002).

Conclusion: The new modified instrumentation seems to be an effective tool to reduce the risk of malalignment of the femoral component in the coronal and in the sagittal plane compared to the conventional phase III instrumentation. Furthermore, the instrumentation is also effective in determining an adequate level of tibial resection and thus avoiding unnecessary bone loss.

Keywords: Bearing size; Implant positioning; Mobile bearing; Osteoarthritis; Oxford Knee; UKA; Unicompartmental knee arthroplasty.

Publication types

Evaluation Study

MeSH terms

Adult
Aged
Aged, 80 and over
Arthroplasty, Replacement, Knee / instrumentation*
Female
Humans
Knee Prosthesis*
Male
Middle Aged
Osteoarthritis, Knee / diagnostic imaging
Osteoarthritis, Knee / surgery*
Prosthesis Design
Reproducibility of Results
Retrospective Studies
Treatment Outcome