Influence of demographics and utilization of physical therapy interventions on clinical outcomes and revision rates following anterior cruciate ligament reconstruction

STUDY DESIGN: Retrospective cohort from the Intermountain Healthcare system, January 2007 to December 2014. BACKGROUND: Recent evolutions in health care delivery are putting physical therapists in the forefront to be more responsible for providing high-quality rehabilitation care in a more cost-effective manner. Studies investigating the association between physical therapy visit utilization and outcomes in vulnerable patient populations following anterior cruciate ligament (ACL) reconstruction may provide useful insights. OBJECTIVES: To examine the relationship between patient age, sex, physical therapy visit utilization, and physical therapy intervention charges with revision rates and patient-reported outcomes in individuals following primary ACL reconstruction. METHODS: A sample of 660 patients who had an ACL reconstruction was identified through an electronic medical record database. Age and physical therapy visit utilization were categorized to examine effects between groups (20 years of age or younger, 21 to 34 years of age, 35 years of age or older; fewer than 9 visits, 9 to 14 visits, 15 or more visits). Multilevel mixed-effects linear models were conducted to compare differences between revision rates and patient-reported outcomes during the episode of care. Receiver operating characteristic curve analyses were also used to determine visit-number and charge-per-visit cut points to discriminate patients who achieved at least a minimal clinically important difference on the patient-reported outcomes. RESULTS: Of 660 patients, 22 (3.3%) had revision surgery. Compared with patients 20 years and younger, the incidence rate ratio of ACL reconstruction revision was lower in patients who were 35 years and older (85%) and 21 to 34 years (59%). Of 470 patients who attended physical therapy for longer than 3 months, change in Knee Outcome Survey activities of daily living subscale score was significantly lower among patients 20 years of age and younger and in the lowest visit category. CONCLUSION: Achievement of favorable outcomes following ACL reconstruction may require categorization of patients beyond surgical diagnosis alone. Younger patients (aged 20 years or less) attending fewer physical therapy visits (fewer than 9) were more likely to have ACL revision surgery and had inferior patient-reported outcomes compared to older patients and those with higher physical therapy visit utilization. The study design of a retrospective cohort limits the ability to identify causal relationships. Additionally, this study was conducted in only 1 geographic region within a single health care delivery system, which may limit the generalizability of the results.