The Influence of Exercise Dosing on Outcomes in Patients With Knee Disorders: A Systematic Review

Study Design Systematic review. Background Therapeutic exercise is commonly used to treat individuals with knee disorders, but dosing parameters for optimal outcomes are unclear. Large variations exist in exercise prescription, and research related to specific dosing variables for knee osteoarthritis, patellar tendinopathy, and patellofemoral pain is sparse. Objectives To identify specific doses of exercise related to improved outcomes of pain and function in individuals with common knee disorders, categorized by effect size. Methods Five electronic databases were searched for studies related to exercise and the 3 diagnoses. Means and standard deviations were used to calculate effect sizes for the exercise groups. The overall quality of evidence was assessed using the Physiotherapy Evidence Database scale. Results Five hundred eighty-three studies were found after the initial search, and 45 were included for analysis after screening. Physiotherapy Evidence Database scale scores were "fair" quality and ranged from 3 to 8. For knee osteoarthritis, 24 total therapeutic exercise sessions and 8- and 12-week durations of exercise were parameters most often associated with large effects. An exercise frequency of once per week was associated with no effect. No trends were seen with exercise dosing for patellar tendinopathy and patellofemoral pain. Conclusion This review suggests that there are clinically relevant exercise dosing variables that result in improved pain and function for patients with knee osteoarthritis, but optimal dosing is still unclear for patellar tendinopathy and patellofemoral pain. Prospective studies investigating dosing parameters are needed to confirm the results from this systematic review. Level of Evidence Therapy, level 1a. J Orthop Sports Phys Ther 2018;48(3):146-161. Epub 10 Jan 2018. doi:10.2519/jospt.2018.7637.