Comparison between semitendinosus transfer to distal femur and medial hamstrings surgical lengthening for treatment of flexed knee gait in cerebral palsy

Abstract

Purpose: Hamstrings surgical lengthening (HSL) has been frequently used for the treatment of flexed knee gait in cerebral palsy; however, recurrence of knee flexion deformity (KFD) and increase of anterior pelvic tilt (APT) were reported in a long-term follow-up. Research question: The aim of this study was to compare semitendinosus transfer to distal femur (STTX) and semitendinosus surgical lengthening (STL) regarding the reduction of KFD and the increase of APT after flexed knee gait treatment. Methods: One hundred and eleven patients were evaluated and they were divided into two groups according to surgical procedures at knees: group A (65 patients/130 knees), including patients who received medial HSL as part of multilevel approach; group B (46 patients/92 knees), represented by patients who underwent orthopedic surgery including an STTX instead of STL. Results: Fixed knee flexion deformity (FKFD) decreased only in group B (from 6.79 degrees to 2.96 degrees, p < 0.001) after intervention. In kinematics, APT increased from 16.38 degrees to 19.03 degrees in group A (p = 0.003), while group B also increased from 15.26 degrees to 20.59 degrees (p < 0.001). The minimum knee flexion in stance phase (MKFS) reduced from 25.34 degrees to 21.65 degrees (p = 0.016) in group A and from 31 degrees to 19.57 degrees (p < 0.001) in group B. In the comparison between groups A and B, the increase of APT (p = 0.028) and reduction of FKFD (p < 0.001), popliteal angle (p = 0.001), bilateral popliteal angle (p = 0.003) and MKFS (p = 0.006) were higher after STTX than STL. Conclusion: In the present study, patients who received STTX exhibited more improvement of knee extension at clinical examination and during gait than those who underwent to STL; however, STTX was not effective to prevent the increase of APT after flexed knee gait treatment.