Characteristics of Usual Physical Therapy Post-Total Knee Replacement and Their Associations With Functional Outcomes

Objective Although total knee replacement (TKR) surgery is highly prevalent and generally successful, functional outcomes post-TKR vary widely. Most patients receive some physical therapy (PT) following TKR, but PT practice is variable and associations between specific content and dose of PT interventions and functional outcomes are unknown. Research has identified exercise interventions associated with better outcomes but studies have not assessed whether such evidence has been translated into clinical practice. We characterized the content, dose, and progression of usual post-acute PT services following TKR, and examined associations of specific details of post-acute PT with patients' 6-month functional outcomes. Methods Post-acute PT data were collected from patients who were undergoing primary unilateral TKR and participating in a clinical trial of a phone-based coaching intervention. PT records from the terminal episode of care were reviewed and utilization and exercise content data were extracted. Descriptive statistics and linear regression models characterized PT treatment factors and identified associations with 6-month outcomes. Results We analyzed 112 records from 30 PT sites. Content and dose of specific exercises and incidence of progression varied widely. Open chain exercises were utilized more frequently than closed chain (median 21 [interquartile range (IQR) 4-49] versus median 13 [IQR 4-28.5]). Median (IQR) occurrence of progression of closed and open chain exercise was 0 (0-2) and 1 (0-3), respectively. Shorter timed stair climb was associated with greater total number of PT interventions and use and progression of closed chain exercises. Discussion Data suggest that evidence-based interventions are underutilized and dose may be insufficient to obtain optimal outcomes.