Comparison of VMO/VL Ratio in Patello-Femoral Pain Syndrome (PFPS) Patients: A Surface EMG Study

Background: PFPS describes anterior and retro patellar knee pain in the absence of other pathology. PFPS is one of the most common disorders of the knee accounts for 25% of knee injuries in sports medicine clinics. Prevalence rate is 20% in USA students and morbidity is directly related to activity of patients. EMG studies of normal subject have revealed that VMO /VL ratio is about 1:1 (power CM et al)

Objective: To study the VMO/VL ratio during ECCENTRIC, CONCENTRIC, ISOMETRIC exercise and Q-angle in PFPS patients and control groups.

Materials & Method: SUBJECTS; 25 diagnosed with PFPS and 25 asymptomatic control were recruited for study. EMG activity of VMO VL was recorded by surface electrodes.EMG data were analyzed in three activities for both groups, ISOMETRIC, CONCENTRIC and ECCENTRIC exercise. Outcome measure was EMG MUAP amplitude and Q-angle.

Results: Results showed that VMO/VL ratio is lower in PFPS subjects. And static and dynamic Qangle is higher for PFPS groups.

Conclusion: There was significant difference in VMO/VL ratio and Q-angle in both groups.