3 years ago

Postoperative fixed flexion deformity greater than 10° lead to poorer functional outcome 10 years after unicompartmental knee arthroplasty

Ngai Nung Lo, Shi-Lu Chia, Darren Keng Jin Tay, Jerry Yongqiang Chen, Seng Jin Yeo, Joel Wei-An Lim, Jared Ze Yang Yeh, Hee Nee Pang

Abstract

Purpose

The primary aim of this study was to evaluate the influence of postoperative fixed flexion deformity (FFD) on the clinical outcomes 10 years after unicompartmental knee arthroplasty (UKA). The secondary aim was to identify predictors for the occurrence of postoperative FFD.

Methods

Patients who underwent UKA between 2003 and 2007 were prospectively followed up for 10 years. A total of 172 patients were categorized into 3 groups based on the amount of postoperative FFD: (1) 0° or less (Min-FFD), (2) 1°–9° (Mid-FFD), and (3) 10° or more (Max-FFD). Functional outcome was quantified using Knee Society Function Score (KSFS), Knee Society Knee Score (KSKS) and Oxford Knee Score (OKS).

Results

At 10 years after UKA, the mean KSKS and OKS were 6 ± 5 (95% CI 6–18, p = 0.050) and 5 ± 2 (95% CI 0–9, p = 0.041) points lower in patients with Max-FFD than those with Min-FFD. Other clinical outcomes were not different between groups. Patients with a higher preoperative body mass index (OR 1.122 per unit increase, 95% CI 1.006–1.253, p = 0.040) or worse preoperative FFD (OR 1.108 per unit increase, 95% CI 1.022–1.201, p = 0.013) were at increased risk of having postoperative FFD of 10° or more at 10 years after UKA.

Conclusions

The clinical relevance of this study was to demonstrate the long-term negative correlation between severe postoperative FFD and functional outcome and, therefore, the importance of achieving good knee alignment after UKA. The authors recommend that FFD should be fully corrected intra-operatively if possible while preserving knee balance and stable dynamic function through full range of motion.

Level of evidence

Prognostic level II.

Publisher URL: https://link.springer.com/article/10.1007/s00167-017-4749-6

DOI: 10.1007/s00167-017-4749-6

You might also like
Never Miss Important Research

Researcher is an app designed by academics, for academics. Create a personalised feed in two minutes.
Choose from over 15,000 academics journals covering ten research areas then let Researcher deliver you papers tailored to your interests each day.

  • Download from Google Play
  • Download from App Store
  • Download from AppInChina

Researcher displays publicly available abstracts and doesn’t host any full article content. If the content is open access, we will direct clicks from the abstracts to the publisher website and display the PDF copy on our platform. Clicks to view the full text will be directed to the publisher website, where only users with subscriptions or access through their institution are able to view the full article.