Comparison of the Effect of Exercise Therapy with Transcutaneous Electrical Nerve Stimulation on Improvement of Pain and Function in Patients with Patellofemoral Pain Syndrome

Introduction & One of the most common disorders of the knee joint in adult is patellofemoral pain syndrome. Sometimes it becomes chronic and causes activity limitation. This study aimed to compare the efficacy of exercise therapy with Transcutaneous Electrical Nerve Stimulation on improvement of pain intensity, knee function, muscle atrophy and range of knee flexion. This double-blind, randomized clinical trial was carried out in Zahedan Razmejo-Moghadam Physiotherapy Clinic, in 2007. Thirty-two patients with patellofemoral pain syndrome were recruited through simple non-probability sampling. Subjects were randomly assigned to one of the equal groups, exercise therapy (including hip, knee, and leg muscles strengthening and stretching exercises) or electrical stimulation group. Before and after intervention, we assessed pain through visual analog scale (VAS) (ordinal), function (ordinal) with Knee Injury and Osteoarthritis Outcome Score (KOOS), thigh circumference with tape measure (centimeter) and range of knee flexion with goniometer (degree). A 10 session treatment program, three sessions per week and one hour per session was performed for both groups. Independent t-test or Mann-Whitney U and paired t-test or Wilcoxon were used for comparison between the pretreatment and post treatment results between groups and within groups, in SPSS software, respectively. The mean total score of knee function increased from 100.53±19.25 to 130.87±18.25 in the electrical stimulation group and from 107.67±22.69 to 131.47±15.11 in the exercise therapy group (p=0.001). The mean score of knee function subscales including; symptoms, pain, functional limitation, recreational activity, and life style improved in both groups (p<0.05). The pain score and range of knee flexion improved in both groups (p<0.05). After treatment, range of knee flexion significantly increased in the exercise group compared with the electrical stimulation one (p=0.008). Each of exercise therapy or transcutaneous electrical nerve stimulation is effective in treatment of patellofemoral pain syndrome. However, exercise therapy is more effective in range of knee flexion increasing.