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Orthopaedic Proceedings
Vol. 91-B, Issue SUPP_II | Pages 350 - 350
1 May 2009
Oberhofer K Mithraratne K Stott S Walt S Anderson I
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Cerebral palsy (CP) results from an injury to the immature brain; and it leads to progressive musculoskeletal (MS) impairment in most affected patients. Orthopaedic surgery involving muscle-tendon lengthening is a method for managing short muscles in CP patients. Knowledge of muscle length prior to surgery is beneficial to surgical success. However, using common assessment methods like 3D gait analysis or physical examination, accurate pre-surgery estimation of muscle lengths during walking is difficult.

Computer models of the lower limbs, which provide more insight into muscle functioning during walking, have become increasingly important within the research field of CP. MS models are commonly driven by joint kinematics from clinical gait analysis. The most often used MS model in CP related research is based on the geometry of an adult human man with muscles modelled as line segments. This approach might be reasonable for small muscles with well-defined paths; however, for long muscles with multiple attachment points and curved paths, a more realistic 3D muscle model is required.

The aim of this study is the development of a clinical assessment tool for CP patients by incorporating kinematic data from gait analysis into a 3D finite-element MS model of the lower limbs. Ethical approval has been obtained to develop subject-specific MS models of 12 children with CP and 12 control children (age 8 – 12 years) based on magnetic resonance images. Kinematic data from 3D gait analysis is used as input data to transform the bony structures. Soft-tissue muscle deformation is modelled according to a variant of free-form deformation called the Host-Mesh Fitting Technique. So far, MS models of the lower limbs of three control children and of one child with CP were developed. The resulting muscle length changes during walking agree reasonably well with published data. The proposed modelling approach together with the library of 24 MS models will enable us to develop a powerful tool to investigate gait of children with CP.


Orthopaedic Proceedings
Vol. 88-B, Issue SUPP_II | Pages 314 - 314
1 May 2006
Mackey A Stott N Walt S Miller F Waugh M
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The aim of this study was to investigate upper limb botulinum toxin A (BTX-A) injections in children with spastic hemiplegia.

Ten children with hemiplegia, aged 10–17 years, received upper limb BTX-A injections and 6 weeks therapy. BTX-A was injected using EMG guidance into elbow and wrist flexors, and forearm pronators (dose 1–2 units/kg body wt (Botox®) per muscle). Follow-up assessments continued to 24 weeks post BTX-A. Outcome measures included three-dimensional (3-D) upper limb analysis of functional tasks, Melbourne Assessment; passive range of motion (PROM), and muscle tone.

There were no serious adverse effects. Elbow flexor muscle tone was reduced to 12 weeks post BTX-A (p < 0.05). Mean passive elbow supination increased by 19 degrees (not significant, p= 0.3). Pre-injection 3-D analysis showed that, compared to controls, children with hemiplegia were slower at performing upper limb reaching tasks, using less elbow extension and supination, and utilising increased compensatory trunk forward flexion. Post BTX-A, the time to complete upper limb tasks did not change (p> 0.15). However, at least six subjects had increased elbow extension (average 17 degrees) and decreased trunk forward flexion (average 16 degrees) during upper limb reaching tasks. Five subjects improved their Melbourne Assessment score by 5% or greater.

Decreased tone and individual improvements in upper limb functional tasks were seen post BTX-A and therapy. However deficits in timing of upper limb movements did not change post BTX-A.


Orthopaedic Proceedings
Vol. 85-B, Issue SUPP_III | Pages 205 - 205
1 Mar 2003
Foster M Hanlon M Stott S Walt S
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The purpose of the study was to evaluate the functional outcome of different limb salvage procedures for osteosarcoma about the knee.

A selection of patients who have undergone limb salvage procedures for osteosarcoma about the knee were invited to join the study. Medical and operation notes were reviewed along with recent radiographs of the involved limb. Patients completed the Musculoskeletal Tumour Society functional questionnaire and underwent a gait analysis assessing walking and running. Most patients had stage 2B osteosarcoma involving either the proximal tibia or distal femur. Limb salvage procedures included arthrodesis, allograft reconstruction, endoprosthesis and rotationplasty.

All patients scored highly (> 70 %) on the MSTS questionnaire except the arthrodesis that scored 57 %. The gait analysis revealed some subtle changes with a quadriceps-sparing gait in the endoprosthesis, mild foot drop in the proximal tibial allograft and a lateral lean of the trunk over the ipsilateral limb in the rotationplasty. The arthrodesis had an obvious straight leg gait with subtle pelvic hiking to assist foot clearance. While analysis of walking was close to normal most patients were unable to obtain a double float and run.

This study shows that limb salvage procedures tailored to each individual case can result in an excellent functional outcome with close to normal gait and high MSTS scores.


Orthopaedic Proceedings
Vol. 85-B, Issue SUPP_III | Pages 206 - 206
1 Mar 2003
Stott N Walt S Lobb G Nicol R Austin N
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The purpose of the study was to document the outcome in adulthood of treatment for idiopathic toe walking.

Twenty of 23 adults who had been previously treated for idiopathic toe walking from 1984 to 1990 were contacted. Three of the 20 subjects lived outside Auckland and four subjects declined to participate, giving a total of 13 subjects suitable for study. All but one of the subjects had had serial casts between the ages of 3.7 to 9.5 years. Six subjects had no further treatment while the other seven subjects went on to surgical lengthening of either TA or calf (average age 10.7 years). All participants underwent 3-D gait analysis and heel-rise test. Average follow-up was 10.8 years (range 5.4–15.6 years). Three patients still had signs of toe walking on visual observation of their gait. The maximum ankle dorsiflexion in stance averaged 90 on 3-D gait analysis (range 20 to 140). Eleven subjects showed maximum ankle dorsiflexion in stance greater than 2 standard deviations below normative values. Nine subjects had abnormal timing of maximal ankle dorsiflexion in stance with maximum ankle dorsiflexion prior to 50 percent of the gait cycle. Only two patients had ankle push off powers below normative values of 2 watts/kg.

This is the first study to report on adults treated for idiopathic toe- walking as children. Most subjects showed restricted range and altered timing of ankle dor-siflexion in gait, however this was detectable visually in only three subjects.