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Which Part of the Triceps Surae Muscle Contributes More to Functional Foot Equinus in Spastic Hemiplegic CP Gait?
Gait & Posture xxx (xxxx) xxx–xxx
Contents lists available at ScienceDirect
Gait & Posture journal homepage: www.elsevier.com/locate/gaitpost
037
Which Part of the Triceps Surae Muscle Contributes More to Functional Foot Equinus in Spastic Hemiplegic CP Gait? Reinald Brunnera,b, Erich Rutza,b, Christian Wyssa,b a b
University Children's Hospital Basel, Basel, Switzerland Basel University, Basel, Switzerland
1. Introduction Equinus deformity is a common complication of patients who suffer from hemiplegic (unilateral) cerebral palsy. Surgical correction is required to restore foot dorsiflexion. Clinically the gastrocnemii part is usually shorter than the soleus. The general opinion is to spare the soleus and if possible focus on lengthening the gastrocnemii doing a vulpius or strayer procedure in order to preserve force of the plantarflexors and to avoid crouching. 2. Research question Does the muscle model calculation from inverse dynamics support the common concept? 3. Methods All patients from the first cohort study where an Achilles tendon lengthening combined with a tibialis anterior shortening was performed (n = 12) were included and their data anonymised. Patients with too poor data were excluded (10 = patients remained). The data before and at the time for the long-term follow-up study were considered. The gait data were imported a slightly changed Lower Leg extremity Model of AnyBody Technology software. The mean of five trials for every patient was compared pre- to postoperative and to normal data (which was equally handled, n=10). Not overlapping standard deviation was
http://dx.doi.org/10.1016/j.gaitpost.2017.06.291
0966-6362/ © 2017 Published by Elsevier B.V.
considered significant. A muscle force (Fig. 3) combined with a negative muscle shortening velocity (Fig. 2) indicated a concentric, with a positive muscle shortening velocity an eccentric contraction. 4. Results Ankle Dorsiflexion reaches a maximum of 0 degrees at 10% of stance phase preoperatively. Later in stance dorsiflexion decreases, indicating the foot going into equinus position. Postoperatively ankle dorsiflexion was very close to normal with a permanent and significant increase between 0% and 45% of stance phase (Fig. 1). Preoperatively the function of the soleus muscle was concentric between 10% and 25%, opposite to normals (Fig. 2, arrow, Fig. 3), which changed to an eccentric contraction at the same phase postoperatively, corresponding to normals. The gastrocnemii muscles in contrast showed an eccentric contraction during 10% and 40% pre- and postoperatively and were not different from normals (Figs. 2,3). 5. Discussion This modelling study shows a completely different muscle action of the soleus muscle compared to the gastrocnemii. Our data indicate that - the soleus muscle shows a more abnormal action than the gastrocnemii, and. - an Achilles tendon lengthening seems to be an adequate procedure to correct the abnormal soleus action.
Gait & Posture xxx (xxxx) xxx–xxx
R. Brunner et al.
Fig. 1. Stance phase covered by grey area (not of interest), black = normal, red = preop.; blue = postop.
2
Contents lists available at ScienceDirect
Gait & Posture journal homepage: www.elsevier.com/locate/gaitpost
037
Which Part of the Triceps Surae Muscle Contributes More to Functional Foot Equinus in Spastic Hemiplegic CP Gait? Reinald Brunnera,b, Erich Rutza,b, Christian Wyssa,b a b
University Children's Hospital Basel, Basel, Switzerland Basel University, Basel, Switzerland
1. Introduction Equinus deformity is a common complication of patients who suffer from hemiplegic (unilateral) cerebral palsy. Surgical correction is required to restore foot dorsiflexion. Clinically the gastrocnemii part is usually shorter than the soleus. The general opinion is to spare the soleus and if possible focus on lengthening the gastrocnemii doing a vulpius or strayer procedure in order to preserve force of the plantarflexors and to avoid crouching. 2. Research question Does the muscle model calculation from inverse dynamics support the common concept? 3. Methods All patients from the first cohort study where an Achilles tendon lengthening combined with a tibialis anterior shortening was performed (n = 12) were included and their data anonymised. Patients with too poor data were excluded (10 = patients remained). The data before and at the time for the long-term follow-up study were considered. The gait data were imported a slightly changed Lower Leg extremity Model of AnyBody Technology software. The mean of five trials for every patient was compared pre- to postoperative and to normal data (which was equally handled, n=10). Not overlapping standard deviation was
http://dx.doi.org/10.1016/j.gaitpost.2017.06.291
0966-6362/ © 2017 Published by Elsevier B.V.
considered significant. A muscle force (Fig. 3) combined with a negative muscle shortening velocity (Fig. 2) indicated a concentric, with a positive muscle shortening velocity an eccentric contraction. 4. Results Ankle Dorsiflexion reaches a maximum of 0 degrees at 10% of stance phase preoperatively. Later in stance dorsiflexion decreases, indicating the foot going into equinus position. Postoperatively ankle dorsiflexion was very close to normal with a permanent and significant increase between 0% and 45% of stance phase (Fig. 1). Preoperatively the function of the soleus muscle was concentric between 10% and 25%, opposite to normals (Fig. 2, arrow, Fig. 3), which changed to an eccentric contraction at the same phase postoperatively, corresponding to normals. The gastrocnemii muscles in contrast showed an eccentric contraction during 10% and 40% pre- and postoperatively and were not different from normals (Figs. 2,3). 5. Discussion This modelling study shows a completely different muscle action of the soleus muscle compared to the gastrocnemii. Our data indicate that - the soleus muscle shows a more abnormal action than the gastrocnemii, and. - an Achilles tendon lengthening seems to be an adequate procedure to correct the abnormal soleus action.
Gait & Posture xxx (xxxx) xxx–xxx
R. Brunner et al.
Fig. 1. Stance phase covered by grey area (not of interest), black = normal, red = preop.; blue = postop.
2