Efficacy and Functional Outcomes of Botulinum Toxin A Injections to Hamstrings in Flexed Knee Gait in Cerebral Palsy

This study proposes to: (1) to determine if injections of BTX-A to the hamstring muscles result in measurable physiologic (body structure and body function) changes not observed with normal saline injections, in children with spastic diplegic CP who walk with a flexed-knee gait pattern; (2) to assess whether physiologic changes translate into functional (activity and participation) improvements; (3) to evaluate family's perception of change in function, activity, participation, and quality of life.

This study will demonstrate if BTX-A injected into overactive hamstring muscles of children with spastic cerebral palsy (CP) and a flexed-knee walking pattern has measurable effects across the spectrum of dimensions of disablement of the International Classification of Functioning, Disability, and Health (ICF). It is a multi-center, prospective, randomized, double-blind trial comparing results of injection of BTX- A and placebo saline in controls, into overactive hamstring muscles, using multiple outcomes measures. Temporal-spatial gait parameters, instrumented 3DGA kinematics, passive ROM, spasticity measurement with both Ashworth and Tardieu scales, muscle strength/control, Gross Motor Function Measurement (GMFM), Pediatric Outcomes Data Collection Instrument (PODCI), Gillette Functional Assessment Questionnaire (FAQ), 6-Minute Walk Test, and Goal Attainment Scale (GAS), assessing all ICF domains, will be collected at baseline and at 1 month, 3 months, and 6 months post-injection. Power analysis demonstrates the need to randomize 250 children (125 with BTX-A, 125 with saline), allowing for attrition. Nine participating hospitals will contribute patients.

Inclusion criteria

• Spastic cerebral palsy;
• Bilateral lower extremity involvement;
• Spasticity present in the hamstrings;
• Flexed knee gait >15 degrees by observation (OGS);
• Age between 3 and 18 years old; (
• GMFCS Level I to Level IV; (
• Able to walk a minimum of 4 complete steps without resting with and without braces/shoes a minimum of 3 times;
• Able to follow simple commands;
• Cooperative with physicians and therapist;
• Able to tolerate application of equipment to the skin.

Exclusion criteria

• Rhizotomy surgery within the last 1 year;
• Lower extremity surgical procedures (soft tissue or bony) within the past 1 year;
• Currently implanted and operating Intrathecal Baclofen Pump (oral baclofen OK);
• Lower extremity BTX-A injections within the past 6 months;
• Multilevel BTX-A injections;
• Gait trainer reliance;
• Serial casting 3 months prior to or during study protocol.