Prevalence and sensitivity of trigger points in lumbo-pelvic-hip muscles in patients with patellofemoral pain syndrome

Objectives: Changes in the activity of the lumbo-pelvic-hip muscles have been established as a major cause of patellofemoral pain syndrome (PFPS), a common orthopedic problem. The present study aimed to compare the prevalence and sensitivity of myofascial trigger points (MTrPs) in lumbo-pelvic-hip muscles in persons with and without PFPS.

Methods: Thirty women with PFPS and 30 healthy women 18-40 years old were recruited for this study. The prevalence of MTrPs was assessed by palpation, and pressure algometry was used to measure the pressure pain threshold. This study evaluated the areas where MTrPs are most commonly found in the lumbar muscles (internal oblique, erector spinae and quadratus lumborum), pelvic muscles (gluteus maximus, gluteus medius, gluteus minimus and piriformis), and hip muscles (hip adductor, quadriceps, hamstring, tensor fascia lata and sartorius). Independent t-tests were used to compare mean pressure pain thresholds between the two groups. Chi-squared tests were used to compare the prevalence of MTrPs.

Results: The prevalence of MTrPs was significantly higher in most of the lumbo-pelvic-hip muscles in patients with PFPS compared to healthy persons. However, there were no significant differences between groups in the prevalence of MTrPs in the gluteus minimus or adductor muscles. The pressure pain threshold in lumbo-pelvic-hip muscles was lower in patients with PFPS compared to healthy participants.

Conclusion: In patients with PFPS the prevalence of MTrPs in the lumbo-pelvic-hip region was higher, and the pressure pain threshold was lower, than in healthy people. Thus therapy to treat PFPS should target the lumbo-pelvic-hip muscles.