Distal hamstring lengthening in cerebral palsy: the influence of the proximal aponeurotic band of the semimembranosus

Abstract

We undertook a prospective review of 24 children with spastic diplegia treated by distal hamstring fractional lengthening at the Sheffield Children's Hospital. In 14 children (24 limbs) the correction achieved (popliteal angle) was inadequate and in these patients in the operating room a further correction was attained by dividing a tight band palpated in the substance of the semimembranosus muscle. Under general anaesthetic (preoperatively) the popliteal angle (a degrees ) was measured using a goniometer, then again (b degrees ) following distal hamstring fractional lengthening and finally (c degrees ) after surgically dividing the tight band. The mean preoperative popliteal angle (a degrees ) in all 24 limbs was 65 degrees (52-90). Following the standard hamstring fractional lengthening it (b degrees ) measured 37 degrees (35-50) and after division of the tight band it (c degrees ) measured 15 degrees (10-20). The reduction in popliteal angle following release of the tight band (proximal aponeurosis) was statistically significant (P<0.05). We undertook a cadaveric examination of 22 lower limbs and confirmed in all the cases that this band was the proximal aponeurosis of the semimembranosus muscle. The proximal aponeurosis is a well defined band located at the anterior aspect of the semimembranosus muscle where it arises from the tendon of the proximal attachment. It is separate from the distal aponeurosis. Division of the proximal aponeurosis during fractional lengthening of the distal hamstring in patients with cerebral palsy results in a significant reduction in the flexion deformity.

Soft Tissue Release and Osteotomies in the Treatment of Patients with Spastic Diplegic Cerebral Palsy

“…The small number of patients participated in this study might limit the data generalisability for this study although the number of study patients was pretty similar in related studies. 10 In conclusion, this is the first study comparing the recovery time, preoperative/postoperative limb power and attitude on surgical decision given a second thought between patients with low and high GMFCS ratings. Our results showed that most patients responded well to the SEMLS treatment.…”

Aponeurotic release of semimembranosus: A technical note to increase correction gained with hamstring lengthening surgery in cerebral palsy

“…To our knowledge, there is no previous study comparing proximal versus distal hamstring lengthening. Release of the aponeurotic band of SM in CP-related knee flexion deformity was first described by Jones et al ( 15 ). In their study, the authors undertook cadaveric dissection to define SM muscle anatomy and evaluated the clinical impact of the release of its proximal aponeurotic band on PA correction.…”

“…The anatomy of the aponeurotic band of SM and its relationship with other important anatomic structures are shown in detail with cadaveric dissection ( Figure 1 ). The release of the thick aponeurosis more distally by splitting the distal SM muscle fibers was previously described by Jones et al ( 15 ). We modified the level of this release by making a transverse stripe about 15 cm proximal to the popliteal skin crease, where the aponeurotic band is sturdy and not covered by SM muscle belly ( Figure 1b ).…”

“…Lengthening at the muscle-tendon junction is thought to be the least disruptive option to preserve muscle function; however, with this technique, minimal acute length gain and incomplete correction of the knee flexion deformity may occur. In an attempt to improve correction without resorting to forceful intraoperative manipulation or lengthening the lateral hamstring, the release of the aponeurotic band of SM can be used in addition to the release of ST in the myotendinous junction and myofascial release of SM ( 15 ). We designed this study to compare the intraoperative corrective effect of the aponeurotic release of SM with the combined myotendinous release of ST and myofascial release of SM, as a single procedure alone or its contribution to correction when all 3 techniques are combined.…”

Changes in Sagittal Plane Kinematics and Kinetics after Distal Release of Medial Hamstrings in Cerebral Palsy

“…Patients who had rectus transfer achieved greater recovery of the knee range of motion than the first group, together with more reduction in the pelvic range of motion and increased hip flexion at initial contact. Jones et al advocated the division of the proximal semimembranosus aponeurosis during fractional lengthening of the distal hamstring in patients with cerebral palsy that resulted in a significant reduction in the flexion deformity [24]. Rectus femoris transfer as part of a single-event multilevel surgery was effective in treating stiff knee gait.…”