Comparing the Outcome of Electrical Stimulation and Physical Therapy in Patellofemoral Pain Syndrome

A Prospective Randomized Study Comparing the Outcome of Electrical Stimulation of Vastus Medialis Obliquus Muscle and Physical Therapy vs Only Physical Therapy But no Electrical Stimulation in Patients With Patellofemoral Pain Syndrome

The purpose of study is to evaluate the efficacy of the electrical muscle stimulation (EMS) device in patients with patellofemoral pain known as anterior knee pain. Usual treatment for it is physical therapy (PT). We want to evaluate and see if adding the electrical muscle stimulation will fasten the recovery and improved outcome in patellofemoral pain syndrome. Half of participants will receive EMS and PT while other half will receive PT only.

The patellofemoral pain syndrome also known as anterior knee pain is a common entity in young athletic population. In patellofemoral knee syndrome, one of the theory is that the vastus medialis obliquus muscle is weak. To strengthen the muscle, physical therapy exercises are commonly used. This study evaluates addition of the electrical muscle stimulation device.The electrical muscle stimulation device "Flex MT Plus" (Electrostim Medical Services Inc. Tampa, FL) is a FDA approved device and has been used in knee for other conditions like treating for weakness associated with knee injuries or after knee surgeries. It has shown to improve the outcomes in above mentioned conditions. Its efficacy has been tested in patellofemoral pain syndrome but in smaller sample size. We intend to test it in larger sample size patient population. Bily et al (2008) (reference #1) published their results on patellofemoral pain syndrome comparing EMS +PT to PT only and found that overall significant improvement in outcome score in all patients but when compared between the groups there was no difference. But there sample size was 19 patients in each group. Small sample size was one of the limitation of their study. We intend to collect 46 patients in each group to find significant difference based on power analysis.

It's a phase III study. A randomized, observer blinded, single center study. Patients will be divided in two groups based on randomization. One group will receive electrical muscle stimulation and Physical therapy and other group will receive only physical therapy. Electrical muscle stimulation device is The Flex MT Plus (Electrostim Medical Services Inc. Tampa, FL) is a neuromuscular stimulator. It is approved by the Food and Drug Administration (FDA). Assessment and follow up will be performed before start of treatment, at 3 weeks, 6 weeks, 12 weeks, 6 months and 12 months post-start of treatment . Assessment will be done at each visit based on Kujala patellofemoral score, pain visual analog scale (VAS) during activities of daily life and isometric strength measurement.

The examiner who will be evaluating and assessing the outcome scores on each visit will be blinded to the patient's group.

The EMS device Flex MT Plus (Electrostim Medical Services Inc. Tampa, FL) is a neuromuscular stimulator. It is approved by the FDA. The Electrical muscle stimulation (EMS) applied to vastus medialis obliquus (VMO) muscle for 20 minutes, 3 times daily and it would be 5 times a week for 12 weeks at 40 Hz. The pulse duration will be 0.26ms, at 5 seconds on and 10 seconds off.

Assessment will be done at each visit (pre-treatment, post-start treatment 3 weeks,, 6 weeks, 12 weeks, 6 months and 12 months) based on Kujala patellofemoral score. The Kujala score assesses following points: Limp, support, walking, stairs, squatting,running, jumping, prolong sitting with knee flexed,pain,swelling,abnormal painful kneecap movements, atrophy of thigh and flexion deficiency. Repeated measures linear regression models will be used to compare the two treatment arms with respect to knee function, pain score, and muscle strength from baseline to 12 months. Total duration of study is two years. We intend finish enrolling 92 patients by the end of one year after start of study. But each patient will be followed for total 12 months period. If any patient enrolled at 1 year mark after start of study , he will be followed for one year.

2 years. Total duration of study is two years. But each patient will be followed for total 12 months after enrollment. If any patient enrolled at 1 year mark after start of study , he will be followed for one year. So total duration of study is 2 years.

Secondary outcome assessment will be to see how many in EMS+PT group and how many in PT group returned to their previous activity level of sports without any pain after completion of treatment.

It will be also noted and compared between the groups at what time period after the start of treatment they returned to their regular sports activities. We hypothesize that EMS group might return early.

Inclusion Criteria: Bilateral/unilateral anterior knee pain for more than 3 moths Age of patient 18 to 40 years At least 3 of the 4 following criteria present: pain associated with prolonged sitting with knees bend, pain with going downstairs, kneeling and squatting or sports activities No h/o injury No h/o surgery to the knee Exclusion Criteria: H/o patellar dislocation or subluxation Associated bursitis, tendinitis in periarticular area Ligamentous problems Intra-articular pathology Pregnancy (patient reported pregnancy, in case of doubt patient will be referred to their OBG/GYN physician to exclude the pregnancy) H/o knee surgery Oral or intraarticular administration of steroid medication with in last 3 months Patients with implanted devices like pacemaker

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