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. 2023 Sep 9:23:101183.
doi: 10.1016/j.artd.2023.101183. eCollection 2023 Oct.

Fixed-Bearing Unicompartmental Knee Arthroplasty of the Lateral Compartment: A Series of 246 Cases

Michael Fitzsimons  1 , Johan van der Stok  1 , Joseph M Queally  1 , Turlough O'Donnell  1   2
Affiliations

Fixed-Bearing Unicompartmental Knee Arthroplasty of the Lateral Compartment: A Series of 246 Cases

Michael Fitzsimons et al. Arthroplast Today. .

Abstract

Background: Isolated osteoarthritis of the lateral compartment of the knee is less common than that of the medial compartment, resulting in significantly fewer lateral unicompartmental knee arthroplasties (UKAs) being performed. This study aimed to evaluate results of a fixed-bearing UKA for the treatment of lateral compartment osteoarthritis of the knee.

Methods: A prospectively collected cohort of 255 patients undergoing fixed-bearing UKA of the lateral compartment using the Triathlon PKR (Stryker, Warsaw, IND) implant with a minimum 2-year follow-up was reviewed. The Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score, radiographic alignment, complications, reoperations, and revisions were recorded. Patient factors and pre- and post-surgical alignment were assessed for their association with a minimum important change (MIC) of the total WOMAC score.

Results: A total of 246 implants with a mean follow-up of 6.6 years (2-10.8 years) were included (4% lost to follow-up). The total WOMAC score increased from 61.3 ± 3.5 to 85.3 ± 7.5, exceeding the MIC in 215 patients (88%). Exceeding the MIC was not associated with age, body mass index, or alignment. The 5-year implant revision rate was 1.6% (3/187).

Conclusions: The fixed-bearing Stryker Triathlon PKR implant for lateral UKA resulted in good clinical outcomes with a low revision rate at midterm follow-up. Body mass index, age, and pre- and post-surgical alignment did not correlate with the clinical outcome. Long-term follow-up is necessary to determine if the clinical improvement and low revision rate can be maintained.

Keywords: Arthroplasty; Fixed-bearing implant; Gonarthrosis; Unicompartmental knee arthroplasty.

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Figures

Figure 1
Figure 1
Image of the Triathlon PKR implant (Stryker, Warsaw, IND).
Figure 2
Figure 2
Box-plot of pre- and post-operative alignment.
Figure 3
Figure 3
Pre- and post-operative radiograph of patient with isolated lateral unicompartmental OA who underwent a lateral UKA using the Triathlon PKR implant. (a) Preoperative anterior-posterior radiograph, (b) postoperative anterior-posterior radiograph, (c) postoperative lateral radiograph.
See this image and copyright information in PMC

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