Autor:innen:
M. Hösl (Vogtareuth, DE)
A. Thamm (Vogtareuth, DE)
S. Nader (Vogtareuth, DE)
S. Berweck (Vogtareuth, DE)
1.Einleitung
Many children with spastic cerebral palsy [SCP] walk with flexed knees [6] which is often attributed to dysfunction of hamstring muscles. Judging muscle functioning is vital when treating patients. Yet, in particular the role of biarticular muscles like the medial hamstrings is subject of controversy. By using motion capturing and musculoskeletal models, muscle-tendon length can be estimated. This approach was recently proposed for indicating soft-tissue surgeries or neurosurgeries [7,8]. We tested the relationship between clinical scales of hamstrings dysfunction, muscle modeling data, and mobility.
2. Fragestellung
How well do clinical scales of hamstrings dysfunction and musculoskeletal modellling from 3D gait analysis [3DGA] relate to everyday mobility of children with spastic cerebral palsy?
3. Methodik
69 ambulatory patients ( 21 / 48 uni- / bilateral SCP, age: 8 ± 4 years) underwent a 3DGA and manual exams of, i.a. kneeflexor strength and muscle tone (mod. Ashworth scale). For popliteal angles, critical pRoM values from the Swedish CPUP-registry [1] were used to judge severity. During 3DGA, we calculated the hamstrings length, excursion and velocity [3]. 34 controls served as reference. Critical muscle pathology during 3DGA was defined as short & slow muscle length or velocities ( < 2 SD from controls). The MobQues47 [4] was used to assess the caregiver-reported everyday mobility. Correlation and regression analysis was done to predict mobility.
4. Ergebnisse
Uni- and bilateral popliteal angle were 56 ± 17° and 40 ± 16°. 76.8 % of SCP-patients would have been calling for treatment (category 'red': > 50° at the CPUP), while only 39.6 % walked with critically short & slow muscle length and velocities. Regarding clinical exams, only kneeflexor strength (r = 0.53 - 0.58, p < 0.01) and muscle tone (r = 0.26 - 0.31, P < 0.05) were significantly related to mobility. During gait, modelled hamstrings, excursion (r = 0.66, P < 0.01) and velocity during swing phase (r = 0.51 - 52, p < 0.05) displayed signifcant relationships to mobility. During multivariate regression, the calculated muscle excursion and clincical strength together explained 56 % of the variance in mobility.
5. Diskussion und Schlussfolgerungen
Clinical values for hamstrings shortness or tone were of limited significance for everyday mobility but in particular weakness and decreased muscle excursion could be decisive. Cut-offs derived from 3DGA currently were a twice as conservative basis for decision-making than the popliteal angle, likely avoiding over-prescriptions of treatment with potentially unfavorable outcome[3]. This method has been successfully applied for the gastrocnemius [5]. A recent consensus thus argued for incooroporation of musculoskeletal modellling for indicating hamstrings surgeries in SCP, too [2]. In future, surface electromyography and motion capturing may also be combined to quantify spasticity features.