Pre-surgical and post-surgical physical therapy for knee replacement patients lowers risk of chronic opioid use

Physical therapy appears to the lower risk of chronic opioid use among patients undergoing total knee replacement, researchers reported on Oct. 27, 2021 in Physical Medicine and Rehabilitation.

The investigators reported that physical therapy within 90 days before or after total knee replacement was associated with lower risk of chronic opioid use. Furthermore, six or more sessions of physical therapy post-surgery was correlated to a lower rate of chronic opioid use, as was physical therapy begun within 30 days of surgery.

“Despite treatment guidelines recommending physical therapy for osteoarthritis [as a first line treatment], utilization of physical therapy remains low,” said investigator Kosaku Aoyagi, Ph.D, a postdoctoral associate at Boston University School of Medicine and researcher at BU’s Arthritis and Autoimmune Diseases Research Center. “In contrast, opioids are not recommended for osteoarthritis yet are commonly prescribed. Our study adds to the growing body of literature that physical therapy interventions can provide meaningful pain management with much lower risk than many pharmacologic options, including opioids.”

The researchers evaluated retrospectively data on 67,322 subjects aged 40 years or older who underwent total knee replacement from January 1, 2001, to December 31, 2016. The subjects were stratified by their history of opioid use. The analyses included data from January 1, 1999, to December 31, 2018.

The investigators evaluated opioid use among subjects who underwent any physical therapy interventions within 90 days before or after total knee replacement, They divided the subjects by number of sessions (1-5, 6-12, and ≥13 sessions), by post-surgical timing for initiation of physical therapy (ie, <30 days, 31-60 days, or 61-90 days after total knee replacement) and by post-surgical type of physical therapy (active or passive).

The primary endpoint was the association of pre- and post-surgical physical therapy with the risk of developing long-term opioid use over 90 days after total knee replacement, adjusted for age, sex, race and ethnicity (Asian, Black, Hispanic, or White), obesity, type of insurance, geographical location, and physical and mental health comorbidities.

Data on 38,408 opioid-naïve subjects (21,336 women, mean age, 66.2 years) and 28,914 opioid-experienced (pre-surgery) subjects (18,426 women, mean age, 64.4 years) were included in the analyses.

The investigators reported that any physical therapy before total knee replacement surgery was associated with a 25% reduced risk of long-term opioid use in the opioid-naive and opioid-experienced cohorts. And receipt of any post-surgical physical therapy was associated with a 25% lower risk of long-term use of opioids in the opioid-experienced group.

When compared to 1 to 5 sessions of physical therapy after surgery, 6 to 12 sessions and 13 or more sessions were associated with lower odds of long-term opioid use in the opioid-experienced group,18% and 29% lower, respectively.

Compared with initiation of physical therapy within 30 days after surgery, initiation 31 to 60 days or 61 to 90 days after surgery were associated with greater odds of long-term opioid use in the opioid-naïve subjects, 145% for 31-60 days and 215% for 61-90 days.

Compared with passive physical therapy, active physical therapy was not associated with any difference in long-term opioid use among opioid-naive or opioid-experienced subjects.

The authors concluded, “This cohort study suggests that receipt of PT [physical therapy] intervention before and after TKR [total knee replacement], receipt of 6 or more sessions of PT care after TKR, and initiation of PT care within 30 days after TKR were associated with lower odds of long-term opioid use. These findings suggest that PT may help reduce the risk of long-term opioid use after TKR.”