Sex Differences and Impact of Body Mass Index on the Time Course of Knee Range of Motion, Knee Strength, and Gait Speed After Total Knee Arthroplasty

Abstract

Objective. Quadriceps strength deficits and gait speed limitations remain significant issues after total knee arthroplasty (TKA), yet detailed longitudinal data characterizing these measures and their predictors are limited. This study aimed to describe the time course of knee range of motion, quadriceps strength, and gait speed post-TKA, and to assess whether sex and body mass index (BMI) influenced the time recovery of these measures. Methods. A total of 1,025 patients (mean 6 SD age 67 6 8 years) undergoing primary TKA participated. At 4-, 8-, 12-, and 16-weeks postsurgery, knee range of motion, quadriceps strength, and gait speed were quantified. The associations of the knee and gait measures profile over time with sex and BMI were assessed using generalized least squares modeling. Results. The various knee and gait measures improved nonlinearly over time, with substantial improvements observed in the first 8-10 weeks postsurgery. Sex and BMI influenced the time course of quadriceps strength (P < 0.001 for all interactions): improvements in quadriceps strength over time were slower in women and in patients with higher BMI. Post-TKA gait speed was consistently lower in women than in men, while BMI was negatively and nonlinearly related to gait speed. Conclusion. Although the various knee and gait measures improved over time, women and patients with higher BMI had poorer functional outcomes. The present study highlights the need for a mechanistic understanding of the results and targeted management of these patient subgroups.

Does BMI influence hospital stay and morbidity after fast-track hip and knee arthroplasty?

“…A possible explanation for this finding would be higher muscle volume in the slightly to moderately overweight patients, facilitating earlier fulfillment of the strictly functional discharge criteria (Husted 2012 )—whereas the very obese patients might be limited in this by having too much body weight, as one study found postoperative improvements in quadriceps function following TKA to be slower in patients with higher BMIs (Pua et al. 2015 ) and a similar underlying mechanism could explain the same finding in THA. As strictly functional discharge criteria were used, and reduced muscle strength has been identified as being 1 of 3 main reasons for delayed discharge (the other 2 being pain and dizziness), the slower regaining of quadriceps strength may result in delayed functional recovery and therefore in a longer time to discharge (Husted et al.…”

Men and Women Demonstrate Differences in Early Functional Recovery After Total Knee Arthroplasty

“…14,15,17,18,48,49 In one study, women demonstrated greater improvement than men on Western Ontario and McMaster Universities Arthritis Index (WOMAC) function and pain scores after TKA. 48 Meanwhile, several studies have shown that women score lower and improve less on the Knee Society Score (KSS) after TKA, 14,16,18,50 while other investigations have indicated no sex differences in KSS.…”

“…A recent study by Pua et al showed that after TKA, women demonstrate slower recovery of quadriceps strength and gait speed compared to men. 49 However, the strength of the current analysis of sex differences is that we used pre-surgery measures to compare to post-operative time points. Use of change values from the pre-surgical time points adjusted for the well-established differences between sexes as a result of OA and allowed for a more complete evaluation of sex differences with respect to functional trajectories over time.…”

Association between rehabilitation attendance and physical function following discharge after total knee arthroplasty: prospective cohort study

“…During each one-to-one rehabilitation session, the physical therapist would review the home exercise program, observe the patients performing the exercises, and correct their form and techniques when necessary. Finally, to monitor treatment progress, patients who attended rehabilitation would undergo a physical assessment involving knee range-of-motion, quadriceps strength, and gait speed testing at 4 weeks and 12 weeks after surgery 8 . Appendix Table II details the inpatient and outpatient rehabilitation programs, and all therapists were trained in the rehabilitation protocols.…”