Variation in ligamentous laxity in well-functioning total knee arthroplasty is not associated with clinical outcomes or functional ability

David F. Hamilton*, Daniel Mandziak, Alexandria Sehgal, Colin R. Howie, Richard Burnett

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

2 Citations (Scopus)

Abstract

Background: Around 20% of revision knee arthroplasty procedures are carried out for a diagnosis of instability. Clinical evaluation of instability is primarily through physical stress testing of knee ligamentous laxity and joint space opening. It is assumed that increased knee ligament laxity is associated with instability of the knee and, by association, reduced physical function. The range of knee ligament laxity in asymptomatic patients with total knee arthroplasty has however not been reported, nor has the association with measures of physical outcomes. Methods: Patients who reported being happy with the outcomes of TKA and denied any feelings of knee instability were evaluated at routine follow-up clinicas. Knee ligamentous stability was evaluated seperately by 2 blinded assessors in both coronal and saggital planes. Assessors classified the ligamentous stability as ‘tight’,‘neutrol’ or ‘loose’. Clinical outcome was evaluated by Oxford Knee Score, patient satisfaction metric, timed performance test, range of motion and lower limb power. Analysis of variance was employed to evaluate variables between groups with post hoc pairwise comparisons. Results: In total, 42 patients were evaluated. Mean time since index surgery was 46 (SD 8) months. In the coronal plane, 11 (26.2%) were categorised as ‘tight’, 22 (52.4%) as ‘neutral’ and 9(21.4%) as ‘loose’. In the sagittal plane, 15 (35.7%) were categorised as ‘tight’, 17 (40.5%) as ‘neutral’ and 10 (23.8%) as ‘loose’. There were no between-group differences in outcomes: Oxford Knee Score, range of motion, lower limb power, timed functional assessment score or in satisfaction response in either plane (p=0.05). Conclusions: We found a range of ligamentous laxityin asymptomatic patients satisfied with the outcome of their knee arthroplasty, and no association between knee laxity and physical ability.

Original languageEnglish
Pages (from-to)827-833
Number of pages7
JournalEuropean Journal of Orthopaedic Surgery and Traumatology
Volume30
Early online date5 Feb 2020
DOIs
Publication statusPublished - Jul 2020

Keywords

  • instability
  • revision total knee arthroplasty
  • clinical outcomes
  • functional assessment

ASJC Scopus subject areas

  • Surgery
  • Orthopedics and Sports Medicine

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