Indian Journal of Orthopaedics

ORIGINAL ARTICLE
Year
: 2019  |  Volume : 53  |  Issue : 2  |  Page : 289--296

New instrumentation improves patient satisfaction and component positioning for mobile-bearing medial unicompartmental knee replacement


Rajesh Malhotra1, Vijay Kumar1, Naman Wahal1, Arnaud Clavé2, James A Kennedy2, David W Murray2, Hemant Pandit3 
1 Department of Orthopaedics, All India Institute of Medical Sciences, New Delhi, India
2 Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences, Botnar Research Centre, University of Oxford, Oxford, UK
3 Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences, Botnar Research Centre, University of Oxford, Oxford; Leeds Institute of Rheumatic and Musculoskeletal Medicine, University of Leeds, Leeds, UK

Correspondence Address:
Mr. James A Kennedy
Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences, Botnar Research Centre, University of Oxford, Windmill Road, Oxford OX3 7LD
UK

Background: The Oxford unicompartmental knee replacement (OUKR) has achieved excellent functional outcomes and long term survivorship in many single center and single surgeon series. However, in national registries, the failure rates are up to three times higher than total knee replacement. This is at least in part due to difficulty experienced by low-volume surgeons in implanting the prosthesis accurately. A new instrumentation system (Microplasty) was introduced to help surgeons achieve better component positioning, however, it is not known whether the new instruments achieve that goal. This study investigates whether the new system achieves better component positioning and whether it improves the clinical outcomes when compared to the existing instruments. Materials and Methods: This retrospective cohort study compared 50 consecutive OUKR implanted using the conventional Phase 3 instrumentation with 100 consecutive OUKR implanted using the new Microplasty instrumentation. Component orientation was measured on postoperative radiographs, and the percentage outside the recommended range was identified. Intraoperative data and retrospectively collected clinical data were also analyzed. Results: Femoral component alignment improved significantly, and there were no outliers in the Microplasty group. Although there were fewer tibial component alignment outliers with Microplasty, the difference was not significant. The intraoperative incidence of tibial recut, patient satisfaction and patient expectations was significantly better in the Microplasty group. The Oxford Knee Scores were also better with Microplasty, however, the difference was not significant. Conclusion: Microplasty instrumentation helps the surgeon achieve optimal component positioning and reduces the need for tibial recut. The clinical outcomes are also better with the Microplasty instrumentation.


How to cite this article:
Malhotra R, Kumar V, Wahal N, Clavé A, Kennedy JA, Murray DW, Pandit H. New instrumentation improves patient satisfaction and component positioning for mobile-bearing medial unicompartmental knee replacement.Indian J Orthop 2019;53:289-296


How to cite this URL:
Malhotra R, Kumar V, Wahal N, Clavé A, Kennedy JA, Murray DW, Pandit H. New instrumentation improves patient satisfaction and component positioning for mobile-bearing medial unicompartmental knee replacement. Indian J Orthop [serial online] 2019 [cited 2019 Sep 23 ];53:289-296
Available from: http://www.ijoonline.com/article.asp?issn=0019-5413;year=2019;volume=53;issue=2;spage=289;epage=296;aulast=Malhotra;type=0