The Effectiveness Of Quadriceps Strengthening Exercises Combined With Neuromuscular Electrical Stimulation on Patellofemoral Pain Syndrome

OBJECTIVE: The weakness of the quadriceps strength in patellofemoral pain syndrome (PFPS) is very evident. Therefore, quadriceps strengthening exercises are very important part of the rehabilitation program. Neuromuscular Electrical Stimulation (NMES) is considered one of the methods for increasing quadriceps muscle strength. To evaluate the effectiveness of combined NMES and strengthening exercises to improve the recovery of quadriceps strength and function in patients with PFPS. METHODS: This study was planned as a randomized controlled pilot study. A total of 27 patients (mean age=38.9±10.8 years, range=20-60 years; 16 females) with PFPS were assessed and randomly assigned into 2 groups. Group I received a standard program (quadriceps strengthening, hip strengthening and hamstring stretching) and NMES combined with quadriceps strengthening exercises simultaneously. Group II received the same standard program without NMES. Both groups were enrolled 3 times per week for 40 minutes per day in 6 weeks. Patients were assessed at the baseline, 3 rd, 6th, and 12th weeks of treatment. Quadriceps strength was evaluated by isokinetic dynamometer. The range of motion at testing was set between 0 for extension to 90 for flexion. The test was performed at 60 degrees/sn and concentric maximum peak torque value was recorded. Kujala and Lysholm scores were used for functional assessments. The data were analyzed using the SPSS 20.0. Shapiro-Wilk test was used to assess the distribution of data. The changes in dependent variables before treatment, 3 rd, 6th, and 12th weeks were analyzed using a 2 by 4 mixed-model analysis of variance (ANOVA). Pairwise comparisons with paired t test were used to determine whether the Group I or Group II, has changed over time. An intention- to- treat analysis was performed to impute values for missing data. An alpha level of 0.05 was established. RESULTS: The study was completed with 20 patients. Group I (n=10; mean age=39.4±8.5 years; 7 females) and group II (n=10; mean age=43.2±11.7 years; 5 females) had no differences in pre-operative measures (p>.05). There was significant improvements in within groups statistics of all parameters for both groups (p<.05). No differences in quadriceps strength, Kujala and Lysholm scores between groups were found at the different time points (F= 0.86; p = 0.12, F=0,001; p =0.97, F=0.12; p=0.73, respectively) CONCLUSION: NMES combined with quadriceps strengthening exercises has no additional effect on PFPS patients’ on muscle strength and function. When considering these results, we believe that there is no need to continue the study in progress.