Botox for Non-surgical Lateral Release in Patellofemoral Pain

Phase 3

Terminated

Conditions: Patellofemoral Pain Syndrome

Interventions: Drug: Botulinum toxin A + exercise
Drug: Placebo

Registration Number: NCT00496964

Lead Sponsor: Virginia Commonwealth University

Brief Summary: The purpose of this study is to determine whether the use of botulinum toxin A injected into the lateral thigh muscle improves knee function and reduces knee pain secondary to patellofemoral syndrome. The study hypothesis is that botulinum toxin + specific exercises will be superior to specific exercises alone in improving knee function and reducing knee pain in individuals with patellofemoral syndrome.

Detailed Description: Patellofemoral pain syndrome is a leading cause of knee pain in persons under 45 and is particularly common in women. The prevailing theory for the etiology of patellofemoral pain is an imbalance in force or timing of the pull of the knee extensor muscles on the patella resulting in improper tracking of the patella in the femoral grove. Specifically, the vastus medialis is thought to be ineffective in overcoming the lateral pull of the vastus lateralis. When exercises designed to focus on improving strength and timing of activation of the vastus medialis fail, surgical release of part of the attachment of the vastus lateralis to the patella is considered.

Botulinum toxin temporarily blocks acetylcholine release from motor neurons and is used clinically to produce muscle relaxation.

Subjects with patellofemoral syndrome will be recruited into the study. Half of the subjects will be given a placebo injection while the other half will be given an injection of Botox (Botulinum Toxin A, Allergen) into the vastus lateralis muscle. Group assignment will be randomized and a double blind protocol used. Prior to injection, the subject will record their level of knee pain, fill out several knee function questionnaires, and have the strength and endurance of their knee extensor muscles tested. All subjects will be given an exercise program designed to target strengthening of the medial thigh muscles as well as stretching of lateral structures.

At 4, 6 and 12 weeks knee pain and knee function will again be assessed.

Recruitment & Eligibility

Status: TERMINATED

Sex: All

Target Recruitment: 5

Inclusion Criteria

retropatellar knee pain
pain with two of: prolonged sitting, climbing stairs, squatting, running, kneeling, hopping, jumping
pain with patellar palpation
symptoms minimum 1 month
Visual Analog Scale for pain (VAS) usual pain 4 of 10 on VAS [0-10 scale, anchors 0 = no pain, 10 = worst pain imaginable]

Exclusion Criteria

history knee surgery
history patellar dislocation
clinical evidence of meniscal lesion, ligamentous instability, traction apophysitis around the patellofemoral complex, patellar tendon pathology, chondral damage, osteoarthrosis, spinal referred pain

Study & Design

Study Type: INTERVENTIONAL

Study Design: PARALLEL

Arm && Interventions

Group	Intervention	Description
1	Botulinum toxin A + exercise	Injection of Botulinum toxin A into vastus lateralis of study limb plus exercise program
2	Placebo	Placebo injection + exercise

Primary Outcome Measures

Name	Time	Method
Visual Analog Scale Pain Ratings (VAS)	4, 6, 12 weeks	Visual Analog Scale pain rating (VAS). 10 cm line with anchors at 0 (no pain) and 10 cm (worst imaginable pain). Scores are in cm (0 - 10) 0 no pain, higher values greater pain. Results given are for change at 12 weeks compared to baseline (week 12 score - baseline score)
Change in Anterior Knee Pain Scale.	4, 6, 12 weeks	Anterior Knee Pain Scale: a 13-item questionnaire; a TOTAL score of 0 = severe disability; a score of 100 = no pain or disability. (items are scored 0-5 or 0-10). Change scores at 12 wks are reported. Inverted so positive values reflect improvement. Included items: difficulty with: weight bearing, walking, stairs, squat, run, jump, prolonged sitting; presence of limp, swelling, patellar subluxation, atrophy of thigh, reduced knee flexion. Reference: Kujala et al: Scoring of Patellofemoral Disorders. J Arthroscopic Rel Surg, 9(2)159-163, 1993
Functional Index Questionnaire	4, 6, 12 weeks	The Functional Index Questionnaire (FIQ) is a self report functional rating scale. Individuals rate eight-activities. Each activity is rated from 0 - 2 with ) being unable to perform the activity and 2 being able to perform the activity without difficulty. The total score is summed for a final score of 0 - 16. 0 indicates that the individual is ubable to perform any of the tasks, 16 indicates that the subject is able to perform all tasks without difficulty. The eight items include: walking (1 block and 1 mile), climbing stairs (2 flights and 4 flights), squatting, kneeling, prolonged sitting, and running
Lower Extremity Functional Scale	4, 6, 12 weeks	The lower extremity functional scale (LEFS) is a self report questionnaire. Subjects rate 19 items related to general activities that require the lower extremities on a scale of 0 - 4. 0 = extreme difficulty or unable to perform the activity, 4 = No difficulty performing the activity. The total of all rankings are summed and divided by the maximum score (76). The score is reported as a percentage. 100% = no difficulty in performing any of the tasks. 0% = extreme difficulty or unable to perform all of the tasks.

Secondary Outcome Measures

Name	Time	Method
Knee Extensor Fatigue	4, 6, 12 weeks	This is not available due to data collection errors
Muscle Activation During Maximal Contractions and Fatigue Contractions	4, 6, 12 weeks	muscle activation as EMG ratios of VMO/VL at 30 degrees maximal isometric contraction at 30degrees
Maximal Knee Extensor Force During Concentric and Isometric Contractions	4, 6, 12 weeks