Background/Purpose: Therapeutic exercise is the most common element of rehabilitation after total hip arthroplasty (THA). To elicit a training effect, interventions must be performed at sufficient doses (frequency, intensity, time, type) as recommended by the American College of Sports Medicine (ACSM). Evaluating the quality of primary studies’ interventions is not part of Cochrane review methodology. Yet, judging an intervention’s likelihood of providing a training effect would inform the assessment of clinical heterogeneity and interpretation of results. Hoogeboom et al. developed a 9-item CONsensus on Therapeutic Exercise aNd Training (CONTENT) scale to assess the therapeutic validity (i.e., quality) of exercise interventions. Thus, the purpose of this study was to 1) assess the therapeutic validity of exercise interventions included in a systematic review of post-acute physical therapy after THA; and 2) determine if they meet ACSM guidelines.

Methods: The methodological quality and results of the Cochrane review were previously presented. This study included trials from the review that focused on exercise interventions. Two researchers (MW & SK) independently extracted data on ACSM exercise dose and overall duration, and applied the CONTENT scale to assess therapeutic validity. Each of the 9 items were rated ‘yes’ or ‘no’ and ‘meeting’ or ‘not meeting’ ACSM guidelines. Studies scoring ³6 were considered to have high therapeutic validity. Disagreements between raters were resolved through discussion and a tie-breaker (DJ) when necessary. Frequency counts and proportions were calculated to determine the number of CONTENT and ACSM items met. We calculated Cohen’s kappa (k) coefficient with 95% confidence intervals for individual and overall CONTENT items to determine strength of agreement between raters. Kappa coefficients ³ 0.60 represented good agreement.

Results: Of the 14 trials in the Cochrane review, 11 were exercise interventions of strength training alone (n=3), neuromotor training alone (n=2), and both (n=6).  Overall, there was substantial agreement between the 2 raters (k 0.71 [CI 0.56, 0.86]) with absolute agreement on 86 of 99 (87%) CONTENT items. Perfect agreement was obtained on items addressing patient selection and exercise intensity and lowest agreement (k 0.23 [CI 0.40, 0.86]) for exercise monitoring/progression. Two interventions were therapeutically valid (Table 1). No interventions met the ACSM criteria. The details most often missing were exercise type and intensity.

Conclusion: This is one of the few analyses conducted to address therapeutic validity of exercise interventions. Post-THA exercise interventions have low therapeutic validity and fail to meet ACSM exercise prescription criteria for health benefits. The conclusions of individual trials, and our and other systematic reviews of THA exercise interventions should be interpreted with caution.