Correlation of Myofascial Trigger Points in Hamstring and Calf Muscle in Patient With Patellofemoral Pain Syndrome

Abstract

Background: Patellofemoral pain syndrome (PFPS) is a prevalent cause of anterior knee pain in young adults and may involve myofascial dysfunction beyond the quadriceps mechanism, including posterior-chain muscles. Objective: To determine the association between myofascial trigger points (MTrPs) in hamstring and calf muscles and PFPS severity. Methods: A cross-sectional observational study was conducted among 197 adults with PFPS recruited by convenience sampling from tertiary care physical therapy settings in Lahore. PFPS severity was categorized as mild, moderate, severe, or extreme, and pain intensity was categorized using Numeric Pain Rating Scale (NPRS) levels. Palpation-based assessment was used to document the presence of hamstring and calf MTrPs and classify participants into calf-only, hamstring-only, or combined hamstring-plus-calf MTrP patterns. Associations between MTrP patterns and PFPS severity were evaluated using Pearson’s chi-square test with effect size estimation. Results: The mean age was 24.95 ± 3.04 years and 72.6% were male. Calf MTrPs were present in 52.8% and hamstring MTrPs in 58.4%. PFPS severity was moderate in 45.7% of participants. PFPS severity differed significantly across posterior-chain MTrP patterns (χ² = 163.67, df = 4, p < 0.001; Cramer’s V = 0.645), with a higher proportion of extreme severity in participants exhibiting combined hamstring and calf MTrPs. Conclusion: Posterior-chain MTrPs are common in PFPS and demonstrate a strong association with PFPS severity, supporting comprehensive myofascial assessment in clinical evaluation and rehabilitation planning