Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
Randomized Controlled Trial
. 2018 Jun;26(6):1662-1670.
doi: 10.1007/s00167-017-4677-5. Epub 2017 Aug 22.

The impact of patient-specific instrumentation on unicompartmental knee arthroplasty: a prospective randomised controlled study

Abtin Alvand  1 , Tanvir Khan  2 , Cathy Jenkins  3 , Jonathan L Rees  2 , William F Jackson  3 , Christopher A F Dodd  3 , David W Murray  2 , Andrew J Price  2
Affiliations
Randomized Controlled Trial

The impact of patient-specific instrumentation on unicompartmental knee arthroplasty: a prospective randomised controlled study

Abtin Alvand et al. Knee Surg Sports Traumatol Arthrosc. 2018 Jun.

Abstract

Purpose: Patient-specific instrumentation (PSI) has been proposed as a means of improving surgical accuracy and ease of implantation during technically challenging procedures such as unicompartmental knee arthroplasty (UKA). The purpose of this prospective randomised controlled trial was to compare the accuracy of implantation and functional outcome of mobile-bearing medial UKAs implanted with and without PSI by experienced UKA surgeons.

Methods: Mobile-bearing medial UKAs were implanted in 43 patients using either PSI guides or conventional instrumentation. Intra-operative measurements, meniscal bearing size implanted, and post-operative radiographic analyses were performed to assess component positioning. Functional outcome was determined using the Oxford Knee Score (OKS).

Results: PSI guides could not be used in three cases due to concerns regarding accuracy and registration onto native anatomy, particularly on the tibial side. In general, similar component alignment and positioning was achieved using the two systems (n.s. for coronal/sagittal alignment and tibial coverage). The PSI group had greater tibial slope (p = 0.029). The control group had a higher number of optimum size meniscal bearing inserted (95 vs 52%; p = 0.001). There were no differences in OKS improvements (n.s).

Conclusion: Component positioning for the two groups was similar for the femur but less accurate on the tibial side using PSI, often with some unnecessarily deep resections of the tibial plateau. Although PSI was comparable to conventional instrumentation based on OKS improvements at 12 months, we continue to use conventional instrumentation for UKA at our institution until further improvements to the PSI guides can be demonstrated.

Level of evidence: Therapeutic, Level I.

Keywords: Arthroplasty; Knee; Patient-specific instrumentation; Unicompartmental knee arthroplasty.

PubMed Disclaimer

Conflict of interest statement

Conflict of interest

The author or one or more of the authors have received or will receive benefits for personal or professional use from a commercial party related directly or indirectly to the subject of this article. In addition, benefits have been or will be directed to a research fund, foundation, educational institution, or other non-profit organisation with which one or more of the authors are associated.

Funding

This study has been supported by the National Institute of Health Research Oxford Biomedical Research Unit.

Ethical approval

For this study ethical approval was obtained, and the trial was registered with the United Kingdom National Research Ethics Service committee (REC reference: 11/H0605/1).

Figures

Fig. 1
Fig. 1
A consolidated standards of reporting trials (CONSORT) diagram showing the flow of patients in the study
Fig. 2
Fig. 2
Bar chart demonstrating the differing bearing sizes implanted in each group
See this image and copyright information in PMC

Similar articles

See all similar articles

Cited by

See all "Cited by" articles

References

    1. Ast MP, Nam D, Haas SB. Patient-specific instrumentation for total knee arthroplasty: a review. Orthop Clin North Am. 2012;43:e17–e22. doi: 10.1016/j.ocl.2012.07.004. - DOI - PubMed
    1. Baker P, Jameson S, Critchley R, Reed M, Gregg P, Deehan D. Center and surgeon volume influence the revision rate following unicondylar knee replacement: an analysis of 23,400 medial cemented unicondylar knee replacements. J Bone Joint Surg Am. 2013;95:702–709. doi: 10.2106/JBJS.L.00520. - DOI - PubMed
    1. Bali K, Walker P, Bruce W. Custom-fit total knee arthroplasty: our initial experience in 32 knees. J Arthroplasty. 2012;27:1149–1154. doi: 10.1016/j.arth.2011.12.006. - DOI - PubMed
    1. Bell SW, Stoddard J, Bennett C, London NJ. Accuracy and early outcomes in medial unicompartmental knee arthroplasty performed using patient specific instrumentation. Knee. 2014;21(Suppl 1):S33–S36. doi: 10.1016/S0968-0160(14)50007-5. - DOI - PubMed
    1. Bruni D, Iacono F, Russo A, Zaffagnini S, Marcheggiani Muccioli GM, Bignozzi S, et al. Minimally invasive unicompartmental knee replacement: retrospective clinical and radiographic evaluation of 83 patients. Knee Surg Sports Traumatol Arthrosc. 2010;18:710–717. doi: 10.1007/s00167-009-0895-9. - DOI - PubMed

Publication types