Article

Total knee arthroplasty (TKA) is associated with declines in hip
abductor (HA) muscle strength; however, a longitudinal analysis demonstrating the
influence of TKA on trajectories of HA strength change has not been conducted.
Objective: The purpose of this study was to quantify changes in HA strength from
pre-TKA through 3 months
post-TKA and to characterize the relationship between HA
strength changes and physical performance.
Design: This study is a post hoc
analysis of a randomized controlled trial. Methods: Data from 162 participants
(89 women, mean age = 63 y) were used for analysis. Data were collected by masked
assessors preoperatively and at 1 and 3 months following surgery. Outcomes
included: Timed "Up and Go" test (TUG), Stair Climbing Test (SCT), Six-Minute
Walk Test (6MWT), and walking speed. Paired t tests were used for between- and
within-limb comparisons of HA strength. Multivariable regression was used to
determine contributions of independent variables, HA and knee extensor strength,
to the dependent variables of TUG, SCT, 6MWT, and walking speed at each time
point. Results: Hip abductor strength was significantly lower in the surgical
limb pre-TKA (mean = 0.015; 95% CI = 0.010-0.020), 1 month post-TKA (0.028;
0.023-0.034), and 3 months post-TKA (0.02; 0.014-0.025) compared with the
nonsurgical limb. Hip abductor strength declined from pre-TKA to 1 month post-TKA
(18%), but not at the 3-month time point (0%). Hip abductor strength
independently contributed to performance-based outcomes pre-TKA; however, this
contribution was not observed post-TKA. Limitations:
The post hoc analysis
prevents examining all outcomes likely to be influenced by HA strength.
Conclusions: Surgical limb HA strength is impaired prior to TKA, and worsens
following surgery. Furthermore, HA strength contributes to performance-based
outcomes, supporting the hypothesis that HA strength influences functional
recovery.

Langue : ANGLAIS