RT Journal A1 Dreher, Thomas A1 Vegvari, Dóra A1 Wolf, Sebastian I. A1 Geisbüsch, Andreas A1 Gantz, Simone A1 Wenz, Wolfram A1 Braatz, Frank T1 Development of Knee Function After Hamstring Lengthening as a Part of Multilevel Surgery in Children with Spastic DiplegiaA Long-Term Outcome Study JF The Journal of Bone & Joint Surgery JO The Journal of Bone & Joint Surgery YR 2012 FD January 18 VO 94 IS 2 SP 121 OP 130 DO 10.2106/JBJS.J.00890 UL http://dx.doi.org/10.2106/JBJS.J.00890 AB Background:  Hamstring lengthening commonly is performed for the treatment of flexed knee gait in patients with spastic diplegic cerebral palsy. Satisfactory short-term results after hamstring lengthening have been demonstrated in various studies. However, evidence for the effectiveness of hamstring lengthening to correct flexed knee gait is scant because of small and inhomogeneous case series, different surgical techniques, and short follow-up.Methods:  The long-term results for thirty-nine patients with spastic diplegia and flexed knee gait who were managed with intramuscular hamstring lengthening as a part of multilevel surgery are presented. Standardized three-dimensional gait analyses and clinical examinations were performed for all patients preoperatively and at one, three, and six to twelve years postoperatively.Results:  Significant improvements in kinematic parameters and the popliteal angle were noted at short-term follow-up (p < 0.01), supporting the results of previous studies. Long-term results showed significant deterioration of minimum knee flexion in stance and the popliteal angle (p < 0.01), whereas the improvements in the Gross Motor Function Classification System and Gillette Gait Index were maintained. This recurrence of flexed knee gait is partial and measurable. Increased pelvic tilt was found in 49% of the limbs postoperatively, which may represent one factor leading to recurrence of flexed knee gait. Genu recurvatum was seen in eighteen patients (twenty-seven limbs; 35%) one year postoperatively, especially in the patients with a jump knee gait pattern preoperatively. At long-term follow-up, genu recurvatum resolved in many limbs, but 12% of the limbs showed residual genu recurvatum, indicating that overcorrection represents a problem following hamstring lengthening.Conclusions:  The results of the present study are crucial for the prognosis of knee function after hamstring lengthening as a part of multilevel surgery. Recurrence and possible overcorrection should be considered in treatment planning.Level of Evidence:  Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.