Effects of distal hamstring lengthening on sagittal motion in patients with diplegia: hamstring length and its clinical use.
This study was undertaken to determine the effect of distal hamstring lengthening (DHL) on hip and knee sagittal kinematics, and to investigate the validity of modeled hamstring length for clinical use. Patient group consisted of 28 patients (56 limbs, mean age 7.4 years) with spastic diplegia who underwent bilateral DHL and tendo-Achilles lengthening with/without rectus femoris transfer (RFT) (DHL+RFT subgroup, 40 limbs; DHL subgroup, 16 limbs). Kinematic data was obtained by gait analysis, and hamstring lengths were obtained using a musculoskeletal modeling technique. Postoperatively, knee extension improved (p<0.001) without aggravating anterior pelvic tilt (p=0.565). However, DHL aggravated anterior pelvic tilt in the DHL subgroup (2.2 degrees, p=0.011). In terms of concurrent validity, hamstring length was found to be correlated with mean pelvic tilt (r=0.798, p<0.001) and popliteal angle (r=-0.425, p=0.001), but the correlation between hamstring length and knee flexion at initial contact was minimal (r=0.068, p=0.753). In terms of construct validity, DHL did not lengthen mean hamstring length (p=0.918). In conclusion, DHL appeared to significantly improve knee motion in patients with spastic diplegia. Furthermore, DHL did not increase pelvic tilt, when performed with RFT. Modeled hamstring length is believed to have limited validity in patients with cerebral palsy, because it does not reflect knee kinematics or postoperative change when DHL was combined with multilevel surgery.
Park
Moon Seok
MS
Department of Orthopedic Surgery, Seoul National University Bundang Hospital, 300 Gumi-Dong, Bundang-Gu, Sungnam, Kyungki 463-707, Republic of Korea.
Chung
Chin Youb
CY
Lee
Sang Hyeong
SH
Choi
In Ho
IH
Cho
Tae-Joon
TJ
Yoo
Won Joon
WJ
Park
B S Myoung Yl
BS
Lee
Kyoung Min
KM
D001696:Biomechanical Phenomena; D016022:Case-Control Studies; D002547:Cerebral Palsy / Q000503:physiopathology / Q000601:surgery*; D002648:Child; D005260:Female; D020233:Gait Disorders, Neurologic / Q000503:physiopathology / Q000601:surgery*; D006801:Humans; D007866:Leg / Q000503:physiopathology / Q000601:surgery*; D008297:Male; D018482:Muscle, Skeletal / Q000503:physiopathology / Q000601:surgery*; D012189:Retrospective Studies; D018709:Statistics, Nonparametric; D016896:Treatment Outcome