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 syndrome is sparse. The aim of this study was to identify specific doses of exercise related to improved outcomes of pain and function in individuals with common knee disorders, categorized by effect size. Five electronic databases were searched for studies related to exercise and the three 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.
583 studies were found after the initial search, and 45 were included for analysis of after screening. PEDro scores were ‘fair’ quality and ranged from 3-8. For knee osteoarthritis, 24 total therapeutic exercise sessions and an 8 and 12 week duration 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 syndrome.
This review suggests there is 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 or patellofemoral pain syndrome. Prospective studies investigating dosing parameters are needed to confirm the results from this systematic review.