Introduction and Aims: We studied the outcome of single event multilevel surgery (SEMLS) for the correction of severe crouch gait in spastic diplegia, over a five-year period. It was unknown if gait correction post-SEMLS could be sustained at skeletal maturity.

Method: This was a prospective cohort study, utilising validated outcome measures. Presenting symptoms were increasingly abnormal gait, anterior knee pain, patellar fractures and fatigue. SEMLS was based on pre-operative gait analysis: mean of seven procedures (range 5–10), including lengthening of contracted muscle-tendon units (particularly hamstrings and psoas), as well as rotational osteotomies and bony stabilisation procedures to correct lever arm dysfunction. Post-operatively subjects wore Ground Reaction Ankle Foot Orthoses (GRAFOs) and received a community-based rehabilitation program. Post-operative changes were evaluated at five years: technical outcome by 3D kinematics and functional outcome by mobility status. Outcomes were analysed with linear regression with robust standard errors.

Results: Eleven children with spastic diplegic cerebral palsy fulfilled the criteria for ‘severe crouch gait’, defined as knee flexion > 30 degrees and ankle dorsiflexion > 15 degrees throughout stance. Ten of 11 subjects had previous Tendo Achilles lengthening. Mean age pre-operatively was 12 years one month (range 8–16) and at follow-up 17 years 10 months (range 16–21). All subjects regained pre-operative mobility levels with improved gait pattern, relief of knee pain and healing of patellar fractures. There was a significant decrease in dependence on assistive devices. Pre- versus five years post-operative kinematics showed clinically and statistically significant increases in knee extension and decreases in ankle dorsiflexion. Improvements were seen in knee extension initial contact (p< 0.001, 95% CI 15°, 31°); maximum knee extension (p< 0.001, 95% CI 16°, 37°), ankle dorsiflexion (p< 0.001, 95% CI 8°, 18°) and plantarflexion 3rd rocker in stance (p=0.03, 95% CI 1°, 17°); knee excursion (p=0.003, 95% CI –24°, −6°), and peak knee flexion timing (p=0.02, 95% CI 2%, 20%).

Conclusion: Multilevel surgery for severe crouch gait in spastic diplegia results in consistently marked improvements in dynamic knee and ankle function, but not at the hip and pelvic levels. The results are durable in most patients, after five years and after reaching skeletal maturity.