Medium-term follow-up of Achilles tendon lengthening in the treatment of ankle equinus in cerebral palsy.
INTRODUCTION: The optimal treatment for equinus of the ankle in ambulatory patients with cerebral palsy is not known. This study assessed the medium term follow-up results of treatment of spastic ankle equinus deformity in cerebral palsy using Hoke or coronal Z-lengthening of the Achilles tendon. It was hypothesized that the use of Achilles tendon lengthening (TAL) as a treatment for spastic ankle equinus during gait results in a high rate of over-weakening of the triceps surae resulting in crouch gait. We also investigated patient characteristics that could identify which patients are at risk for crouch gait due to triceps surae weakening from Achilles tendon lengthening. MATERIALS AND METHODS: Seventy-nine patients (114 procedures) who had undergone Achilles lengthening were retrospectively reviewed to determine how many patients developed crouch gait with dorsiflexion of the ankle throughout stance phase requiring anterior-floor-reaction bracing. The following patient characteristics were evaluated: age at surgery, geographic type of cerebral palsy, length of follow-up, need for anterior-floor-reaction bracing, length of time after surgery when brace was prescribed, age at time of need for bracing, side of surgery, technique used, additional procedures performed at time of TAL, previous or later procedures performed, and walking ability. RESULTS: The average age at the time of TAL was 7 years and 3 months, and the average follow-up was seven years. The geographic type of cerebral palsy greatly affected the outcome. None of the twenty-three hemiplegic patients required bracing. Fourteen of 34 (41%) patients with spastic diplegia and seven of fourteen (50%) patients with spastic quadriplegia required bracing. There was no significant difference in outcome between the Hoke and the Z-lengthening procedures. Patients who underwent more procedures and bilateral procedures were more likely to require anterior-floor-reaction bracing. CONCLUSIONS: Achilles tendon lengthening as practiced by the senior author results in a high rate of over weakening of the triceps surae as defined by the need for a floor reaction brace. Results are best in patients with hemiplegia and non-hemiplegic patients who require only single leg surgery, and who do not require concomitant or subsequent surgery. Alternative treatment, such as gastrocnemius fascial lengthening, or non-surgical treatment may be the optimal treatment of ambulatory patients with spastic diplegia and quadriplegia who have spastic ankle equinus during gait.