Effects of Manual Therapy and Strengthening Exercise on Pain in Patients with Knee Osteoarthritis: A Systematic Review and Meta-Analysis

This systematic review and meta-analysis aimed to determine whether manual therapy (MT) and strengthening exercises (SE) reduce pain in patients with knee osteoarthritis (KO). Clinical trials were identified through a search of PubMed, PEDro, Scopus, and Ovid databases up to April 2024. Two independent reviewers screened articles, removing duplicates, and conducted full-text evaluations. Nineteen studies were included, with eight incorporated into the meta-analysis. Of these, seven addressed MT and twelve focused on SE. Although the studies included a variety of outcomes and follow-up periods, both interventions were shown to reduce pain immediately after the intervention, with MT providing superior short-term outcomes. Improvements were noted in the VAS scale for the MT group (effect size = 0.799; Z = 2.495; p = 0.013; IC 95%= 0.171 to 1.427; Q-value = 17.721; p = 0.001) and in the WOMAC pain score for the SE compared to controls (effect size = 0.364; Z = 1.993; p = 0.046; IC 95%= 0.006 to 0.722; Q-value = 2.4; p = 0.301). Both results showed high evidence according to GRADE. However, long-term effects are inconclusive, with low/very low levels of evidence. Both MT and SE are effective interventions in reducing pain in the short term. However, more clinical trials are needed to determine the best doses and the long-term effects.