Calcaneal gait in spastic diplegia after heel cord lengthening: a study with gait analysis

Outcome of Gastrocnemius Soleus Facial Lengthening in Ambulatory Patients With Cerebral Palsy

BACKGROUND

Treatment of equinus contractures in children with cerebral palsy (CP) varies across centers. Existing literature utilizes mixed study populations with a variety of procedures. As such, there is limited knowledge regarding recurrence rates and efficacy of a single procedure performed on a homogenous cohort. Here we retrospectively evaluate outcomes from gastroc soleus fascial lengthenings (GSFL) performed at 2 centers with consistent approaches in both patient selection and operative technique.

METHODS

Subjects meeting inclusion criteria including CP diagnosis, ambulation status, and minimum follow-up criteria were identified. Revision rate was reported based on need for additional calf lengthening procedures. Functional outcomes were evaluated using physical exam measures and selected variables from computational gait analysis. Outcomes factors were identified by comparing revised subjects to unrevised. Longitudinal outcomes of index surgeries were assessed by comparing preoperative functional data to short-term, mid-term, and long-term data.

RESULTS

A total of 64 subjects with 87 limbs met inclusion criteria. In all, 25% of subjects and 21% of limbs went on to revision. Factors influencing revision were age at index surgery and gross motor function classification system (GMFCS) level. More than half of revised limbs had index surgery before age 7. Revision rates for subjects less than 7 were 44% compared with a 17% revision rate for ages 7 to 12, and a 4% revision rate on children older than 12. GMFCSIII subjects had significantly higher revision rates (43%) compared with GMFCSII (18%) and GMFCSI (11%) subjects. Ankle range of motion measures improved significantly with GSFL and most maintained improvements at all time periods. GSFL did not lead to significant calcaneal gait or crouch.

CONCLUSIONS

This study evaluates long term efficacy of GSFL to address equinus in ambulatory children with CP. Overall revision rates are similar to previous reports for GSFL and other calf lengthening procedures. This information may be useful in setting expectations and counselling families. Younger subjects and those with more severe involvement are more likely to need revision surgery, with these factors compounding the likelihood in the younger GMFCSIII child.

LEVEL OF EVIDENCE

Level III-retrospective comparative study.

Evaluation of Peripheral Perfusion in the Presence of Plantar Heel Ulcerations Status After Transmetatarsal Amputation With Achilles Tendon Lengthening

The objective of this study is to evaluate peripheral perfusion in patients who developed plantar heel ulcerations status after transmetatarsal amputation and Achilles tendon lengthening. Peripheral perfusion was assessed via contrast angiography of the 3 crural vessels (anterior tibial, posterior tibial, and peroneal arteries), as well as intact heel blush and plantar arch. The secondary objective is to correlate the arterial flow to time to develop heel ulceration and incidence of minor and major lower-extremity amputation. Diagnostic angiography without intervention was performed on 40% of patients (4/10), and interventional angiography was performed on 60% of patients (6/10). In-line flow was present in 0% (0/10) of the peroneal arteries, 60% (6/10) of the anterior tibial arteries, and 70% (7/10) of the posterior tibial arteries. Heel angiographic contrast blush was present in 60% (6/10), and intact plantar arch was present in 60% (6/10). Patients developed heel ulcerations at a mean time of 7.6 months (range 0.7 to 41.2) postoperatively. The incidence of major lower-extremity amputation was 30% (3/10), with a mean time of 5.2 months (range 3.5 to 8.3) from time of heel wound development. No amputation occurred in 6 patients (60%). Among them, intact anterior tibial inline arterial flow was present in 3, intact posterior tibial inline arterial flow was present in 6, and heel blush was present in 5. Our results demonstrate that an open calcaneal branch of the posterior tibial artery is sufficient to heal plantar heel ulcerations to potentially increase rates of limb salvage.

Endoscopic Transverse Gastrocsoleus Recession in Children With Cerebral Palsy

Aim: The aim of this study was to evaluate the surgical outcome, in terms of gait improvement, of endoscopic transverse Vulpius gastrocsoleus recession in children with cerebral palsy compared to the traditional open surgery. Methods: Twenty-seven children with cerebral palsy who had undergone endoscopic transverse Vulpius gastrocsoleus recession were reviewed. For the comparison of gait improvement, independent ambulatory spastic diplegic patients who had undergone only endoscopic transverse Vulpius gastrocsoleus recession on both legs were selected. Seven (14 legs) children were included and the median age was 7 years (6-9 years). Seven age-matched patients with the same inclusion/exclusion criteria who underwent open surgery were selected as the control group. Physical examination and gait parameters were evaluated and compared between groups, including the gait deviation index (GDI), and gait profile score (GPS). Results: There was no significant complication in twenty-seven children after endoscopic transverse Vulpius gastrocsoleus recession. However, one patient required a revision open surgery at postoperative 1 year 9 months due to the recurrence of equinus and the incomplete division of the midline raphe which was noted during surgery. When comparing gait improvements, there were no differences between the endoscopic and open surgery groups in ankle dorsiflexion angle, ankle kinetics, GDI, and GPS. The postoperative peak ankle dorsiflexion during stance phase was slightly higher in the open group. Conclusion: This is the first study that evaluates gait improvement exclusively for children with spastic diplegia after endoscopic transverse Vulpius gastrocsoleus recession. The gait improvements after endoscopic surgery were comparable to the open surgery, however, the possibility of reduced improvement in ankle kinematics should be considered.

Predicting gait adaptations due to ankle plantarflexor muscle weakness and contracture using physics-based musculoskeletal simulations

Deficits in the ankle plantarflexor muscles, such as weakness and contracture, occur commonly in conditions such as cerebral palsy, stroke, muscular dystrophy, Charcot-Marie-Tooth disease, and sarcopenia. While these deficits likely contribute to observed gait pathologies, determining cause-effect relationships is difficult due to the often co-occurring biomechanical and neural deficits. To elucidate the effects of weakness and contracture, we systematically introduced isolated deficits into a musculoskeletal model and generated simulations of walking to predict gait adaptations due to these deficits. We trained a planar model containing 9 degrees of freedom and 18 musculotendon actuators to walk using a custom optimization framework through which we imposed simple objectives, such as minimizing cost of transport while avoiding falling and injury, and maintaining head stability. We first generated gaits at prescribed speeds between 0.50 m/s and 2.00 m/s that reproduced experimentally observed kinematic, kinetic, and metabolic trends for walking. We then generated a gait at self-selected walking speed; quantitative comparisons between our simulation and experimental data for joint angles, joint moments, and ground reaction forces showed root-mean-squared errors of less than 1.6 standard deviations and normalized cross-correlations above 0.8 except for knee joint moment trajectories. Finally, we applied mild, moderate, and severe levels of muscle weakness or contracture to either the soleus (SOL) or gastrocnemius (GAS) or both of these major plantarflexors (PF) and retrained the model to walk at a self-selected speed. The model was robust to all deficits, finding a stable gait in all cases. Severe PF weakness caused the model to adopt a slower, "heel-walking" gait. Severe contracture of only SOL or both PF yielded similar results: the model adopted a "toe-walking" gait with excessive hip and knee flexion during stance. These results highlight how plantarflexor weakness and contracture may contribute to observed gait patterns.

Rapid predictive simulations with complex musculoskeletal models suggest that diverse healthy and pathological human gaits can emerge from similar control strategies

Physics-based predictive simulations of human movement have the potential to support personalized medicine, but large computational costs and difficulties to model control strategies have limited their use. We have developed a computationally efficient optimal control framework to predict human gaits based on optimization of a performance criterion without relying on experimental data. The framework generates three-dimensional muscle-driven simulations in 36 min on average—more than 20 times faster than existing simulations—by using direct collocation, implicit differential equations and algorithmic differentiation. Using this framework, we identified a multi-objective performance criterion combining energy and effort considerations that produces physiologically realistic walking gaits. The same criterion also predicted the walk-to-run transition and clinical gait deficiencies caused by muscle weakness and prosthesis use, suggesting that diverse healthy and pathological gaits can emerge from the same control strategy. The ability to predict the mechanics and energetics of a broad range of gaits with complex three-dimensional musculoskeletal models will allow testing novel hypotheses about gait control and hasten the development of optimal treatments for neuro-musculoskeletal disorders.

The development of spasticity with age in 4,162 children with cerebral palsy: a register-based prospective cohort study

Background and purpose - Spasticity is often regarded as a major cause of functional limitation in children with cerebral palsy (CP). We analyzed the spasticity development with age in the gastrosoleus muscle in children with CP. Children and methods - This is a longitudinal cohort study of 4,162 children (57% boys) with CP born in 1990-2015, monitored using standardized follow-up examinations in the Swedish surveillance program for CP. The study is based on 57,953 measurements of spasticity of the gastrosoleus muscle assessed using the Ashworth scale (AS) in participants between 0 and 15 years of age. The spasticity was analyzed in relation to age, sex, and Gross Motor Function Classification System (GMFCS) levels using a linear mixed model. Development of spasticity with age was modeled as a linear spline. Results - The degree of spasticity increased in most children over the first 5 years of life. At 5 years of age, 38% had an AS level of ≥ 2. The spasticity then decreased for 65% of the children during the remaining study period. At 15 years of age only 22% had AS ≥ 2. The level of spasticity and the rate of increase and decrease before and after 5.5 years of age were higher in children at GMFCS IV-V. Interpretation - The degree of spasticity of the gastrosoleus muscle often decreases after 5 years of age, which is important for long-term treatment planning and should be considered in spasticity management.

Predictors of Walking Efficiency in Children With Cerebral Palsy: Lower-Body Joint Angles, Moments, and Power

BACKGROUND

People with cerebral palsy (CP) experience increased muscle stiffness, muscle weakness, and reduced joint range of motion. This can lead to an abnormal pattern of gait, which can increase the energy cost of walking and contribute to reduced participation in physical activity.

OBJECTIVE

The aim of the study was to examine associations between lower-body joint angles, moments, power, and walking efficiency in adolescents with CP.

DESIGN

This was a cross-sectional study.

METHODS

Sixty-four adolescents aged 10 to 19 years with CP were recruited. Walking efficiency was measured as the net nondimensional oxygen cost (NNcost) during 6 minutes of overground walking at self-selected speed. Lower-body kinematics and kinetics during walking were collected with 3-dimensional motion analysis, synchronized with a treadmill with integrated force plates. The associations between the kinematics, kinetics, and NNcost were examined with multivariable linear regression.

RESULTS

After adjusting for age, sex, and Gross Motor Function Classification System level, maximum knee extension angle (β = -0.006), hip angle at midstance (β = -0.007), and maximum hip extension (β = -0.008) were associated with NNcost. Age was a significant modifier of the association between the NNcost and a number of kinematic variables.

LIMITATIONS

This study examined kinetic and kinematic variables in the sagittal plane only. A high interindividual variation in gait pattern could have influenced the results.

CONCLUSIONS

Reduced knee and hip joint extension are associated with gait inefficiency in adolescents with CP. Age is a significant factor influencing associations between ankle, knee, and hip joint kinematics and gait efficiency. Therapeutic interventions should investigate ways to increase knee and hip joint extension in adolescents with CP.

Stair-shaped Achilles tendon lengthening in continuity - A new method to treat equinus deformity in patients with spastic cerebral palsy

BACKGROUND

Equinus of the ankle is a common deformity in spastic cerebral palsy. Achilles tendon lengthening is one of the effective options for the treatment of equinus deformity.

METHODS

In the study, a new stair-shaped Achilles tendon lengthening (ATL) procedure that preserves of the tendon continuity was performed in 28 tendons with equinus deformity (20 patients, mean age=10.5±2.6 years). The results were compared with a group of patients treated with the Z-lengthening procedure. During the latest follow-up visit, the American Orthopaedic Foot & Ankle Society (AOFAS) Ankle-Hindfoot scale score was much higher in the stair-shaped ATL group than in the Z-lengthening group (p<0.05).

RESULTS

The two groups showed similar surgical correction angle after ATL(37.2±3.5° for stair-shaped ATL and 36.1±4.5° for Z-lengthening). During the latest follow-up visit, the correction angle in the Z-lengthening group decreased to 21.6±4.3°, which was lower than in the stair-shaped ATL group (29.0±3.1°; p<0.05). In addition, the data regarding the time required by each patient before being able to start rehabilitation and walking as well as gaining better stability for running indicated that the stair-shaped ATL group recovered significantly quicker than the Z-lengthening group.

CONCLUSIONS

The stair-shaped ATL procedure resulted in a successful correction of the equinus deformity in spastic cerebral palsy, with the advantage of preserving a degree of continuity without a complete section of the tendon. This confers greater antigravity stability and quicker recovery in patients.

Resistance Training Combined With Stretching Increases Tendon Stiffness and Is More Effective Than Stretching Alone in Children With Cerebral Palsy: A Randomized Controlled Trial

Aim: Stretching is often used to increase/maintain muscle length and improve joint range of motion (ROM) in children with cerebral palsy (CP). However, outcomes at the muscle (remodeling) and resulting function appear to be highly variable and often unsatisfactory. During passive joint rotation, the Achilles tendon lengthens more than the in-series medial gastrocnemius muscle in children with CP, which might explain the limited effectiveness of stretching interventions. We aimed to ascertain whether increasing tendon stiffness, by performing resistance training, improves the effectiveness of passive stretching, indicated by an increase in medial gastrocnemius fascicle length. Methods: Sixteen children with CP (Age median [IQR]: 9.6 [8.6, 10.5]) completed the study. Children were randomly assigned to a combined intervention of stretching and strengthening of the calf muscles (n = 9) or a control (stretching-only) group (n = 7). Medial gastrocnemius fascicle length at a resting ankle angle, lengthening during passive joint rotations, and tendon stiffness were assessed by combining dynamometry and ultrasound imaging. The study was registered on clinicaltrials.gov (NCT02766491). Results: Resting fascicle length and tendon stiffness increased more in the intervention group compared to the control group (median [95% CI] increase fascicle length: 2.2 [1.3, 4.3] mm; stiffness: 13.6 [9.9, 17.7] N/mm) Maximum dorsiflexion angle increased equally in both groups. Conclusion: This study provides proof of principle that a combined resistance and stretching intervention can increase tendon stiffness and muscle fascicle length in children with CP. This demonstrates that remodeling of muscle structure is possible with non-invasive interventions in spastic CP.

Use of 3D gait analysis as predictor of Achilles tendon lengthening surgery outcomes in children with cerebral palsy

BACKGROUND

In children with spastic cerebral palsy (CP), the treatment of equinus foot with Achilles tendon lengthening (ATL) surgery is associated with high incidence of overcorrection, which may result in crouch gait.

AIM

We aimed to assess if gait pattern in preoperative time could be a predictor of the surgery outcome.

DESIGN

Cross-sectional retrospective study.

SETTING

Movement Analysis Lab of IRCCS San Raffaele Pisana Hospital in Rome (Italy).

POPULATION

Eighteen children (mean age 9.6±4.7 years) with spastic diplegia CP who underwent bilateral ATL surgery to correct equinus foot were involved.

METHODS

Participants underwent 3D gait analysis before and approximately 12 months after surgery. Primary measures were spatiotemporal, kinematic (summarized by Gait Variable Scores, GVSs) and kinetic parameters. The gait patterns for each leg was defined from kinematic data, using a quantitative classification: plantar flexor knee extension (PFKE) index. The CP group was split into true equinus and jump gait.

RESULTS

The equinus foot was successfully corrected as demonstrated by the improvement of GVS ankle dorsi-plantarflexion. However, there was a high rate of overcorrection in the true equinus, characterized by increases in knee flexion-extension GVS (8.7° pre vs. 16.7° post P<0.05) and knee flexion angle at initial contact (5.2° vs. 20.6° P<0.05) and by a decrease in the maximum ankle power generated at push-off (1.49 vs. 0.83 W/kg P<0.05).

CONCLUSIONS

Assessment of motor phenotype in preoperative time are good predictors of the results of ATL surgery. In children with true equinus gait, the increase of knee flexion subsequent to ATL is an early indicator that this technique will lead to crouch gait. These results show the influence of true equinus and jump gait patterns on the outcomes of the ATL.

CLINICAL REHABILITATION IMPACT

Therefore, we propose that this approach could have clinical value to evaluate and prescribe rehabilitation in children with CP disease, proposing different solutions depending on motor phenotype.

The design of a functional assessment and gait analysis facility for rehabilitation studies

A general functional assessment and gait facility has been designed for use in all aspects of measurement of handicap. The functional assessment course contains various features to assess the ability of subjects with different handicaps to sit, take off and apply orthotic or prosthetic devices, climb ramps and steps, negotiate corners, and doors with different locking and opening mechanisms. Incorporated in the middle of the walking section of the course is a force plate to assess the mechanical function of orthoses or prostheses by a force vector visualization system. A visual analogue scoring system of the quality of performance of the various tasks encountered on the functional assessment course as well as the freely selected speed and fastest walking in a straight line has been adopted. This visual analogue score is marked after analysing the video record obtained from a mobile colour camera. The doors, ramps and walking area are wide enough to assess wheelchair use. We have adopted a 'gait graph' for the gait analyses using a 10m straight walkway and measuring the temporal parameters at free speed walking and the fastest walking speed. Energy cost is measured using heart rate monitoring by telemetry on the functional assessment course and during gait analysis.

It is proposed to use this facility for the assessment and management of lower limb bracing in children, patients undergoing corrective surgery on the lower limb and for wheelchair users.

The transverse Vulpius gastrocsoleus recession for equinus gait in children with cerebral palsy

We report the results of Vulpius transverse gastrocsoleus recession for equinus gait in 26 children with cerebral palsy (CP), using the Gait Profile Score (GPS), Gait Variable Scores (GVS) and movement analysis profile. All children had an equinus deformity on physical examination and equinus gait on three-dimensional gait analysis prior to surgery. The pre-operative and post-operative GPS and GVS were statistically analysed. There were 20 boys and 6 girls in the study cohort with a mean age at surgery of 9.2 years (5.1 to 17.7) and 11.5 years (7.3 to 20.8) at follow-up. Of the 26 children, 14 had spastic diplegia and 12 spastic hemiplegia. Gait function improved for the cohort, confirmed by a decrease in mean GPS from 13.4° pre-operatively to 9.0° final review (p < 0.001). The change was 2.8 times the minimal clinically important difference (MCID). Thus the improvements in gait were both clinically and statistically significant. The transverse gastrocsoleus recession described by Vulpius is an effective procedure for equinus gait in selected children with CP, when there is a fixed contracture of the gastrocnemius and soleus muscles.

High resolution muscle measurements provide insights into equinus contractures in patients with cerebral palsy

Muscle contractures that occur after upper motor neuron lesion are often surgically released or lengthened. However, surgical manipulation of muscle length changes a muscle's sarcomere length (Ls ), which can affect force production. To predict effects of surgery, both macro- (fascicle length (Lf )) and micro- (Ls ) level structural measurements are needed. Therefore, the purpose of this study was to quantify both Ls and Lf in patients with cerebral palsy (CP) as well as typically developing (TD) children. Soleus ultrasound images were obtained from children with CP and TD children. Lf was determined and, with the joint in the same position, CP biopsies were obtained and formalin fixed, and Ls was measured by laser diffraction. Since soleus Ls values were not measurable in TD children, TD Ls values were obtained using three independent methods. While average Lf did not differ between groups (CP=3.6±1.2 cm, TD=3.5±0.9 cm; p>0.6), Ls was dramatically longer in children with CP (4.07±0.45 µm vs. TD=2.17±0.24 µm; p<0.0001). While Lf values were similar between children with CP and TD children, this was due to highly stretched sarcomeres within the soleus muscle. Surgical manipulation of muscle-tendon unit length will thus alter muscle sarcomere length and change force generating capacity of the muscle.

The operative correction of symptomatic flat foot deformities in children: the relationship between static alignment and dynamic loading

At our institution surgical correction of symptomatic flat foot deformities in children has been guided by a paradigm in which radiographs and pedobarography are used in the assessment of outcome following treatment. Retrospective review of children with symptomatic flat feet who had undergone surgical correction was performed to assess the outcome and establish the relationship between the static alignment and the dynamic loading of the foot. A total of 17 children (21 feet) were assessed before and after correction of soft-tissue contractures and lateral column lengthening, using standardised radiological and pedobarographic techniques for which normative data were available. We found significantly improved static segmental alignment of the foot, significantly improved mediolateral dimension foot loading, and worsened fore-aft foot loading, following surgical treatment. Only four significant associations were found between radiological measures of static segmental alignment and dynamic loading of the foot. Weakness of the plantar flexors of the ankle was a common post-operative finding. Surgeons should be judicious in the magnitude of lengthening of the plantar flexors that is undertaken and use techniques that minimise subsequent weakening of this muscle group.

Multilevel surgery for equinus gait in children with spastic diplegic cerebral palsy: medium-term follow-up with gait analysis

BACKGROUND

In children with spastic diplegia, surgery for ankle equinus contracture is associated with a high prevalence of both overcorrection, which may result in a calcaneal deformity and crouch gait, and recurrent equinus contracture, which may require revision surgery. We sought to determine if conservative surgery for equinus gait, in the context of multilevel surgery, could result in the avoidance of overcorrection and crouch gait as well as an acceptable rate of recurrent equinus contracture at the time of medium-term follow-up.

METHODS

This was a retrospective, consecutive cohort study of children with spastic diplegia who had had surgery for equinus gait between 1996 and 2006. All children had distal gastrocnemius recession or differential gastrocnemius-soleus complex lengthening, on one or both sides, as part of single-event multilevel surgery. The primary outcome measures were the Gait Variable Scores (GVS) and Gait Profile Score (GPS) at two time points after surgery.

RESULTS

Forty children with spastic diplegia, Gross Motor Function Classification System (GMFCS) level II or III, were included in this study. There were twenty-five boys and fifteen girls. The mean age was ten years at the time of surgery and seventeen years at the time of final follow-up. The mean postoperative follow-up period was 7.5 years. The mean ankle GVS improved from 18.5° before surgery to 8.7° at the time of short-term follow-up (p < 0.005) and 7.8° at the time of medium-term follow-up. The equinus gait was successfully corrected in the majority of children, with a low rate of overcorrection (2.5%) and a high rate of recurrent equinus (35%), as determined by sagittal ankle kinematics. Mild recurrent equinus was usually well tolerated and conferred some advantages, including contributing to strong coupling at the knee and independence from using an ankle-foot orthosis.

CONCLUSIONS

Surgical treatment for equinus gait in children with spastic diplegia was successful, at a mean of seven years, in the majority of cases when combined with multilevel surgery, orthoses, and rehabilitation. No patient developed crouch gait, and the rate of revision surgery for recurrent equinus was 12.5%.

Mesh Achilles tendon lengthening--a new method to treat equinus deformity in patients with spastic cerebral palsy: surgical technique and early results

Equinus of the ankle is a common deformity in spastic cerebral palsy. Many methods have been developed to lengthen the Achilles tendon to correct the deformity. A new mesh Achilles tendon lengthening (ATL) procedure that might decrease immobilization and promote recovery was performed in 36 tendons with equinus deformity (22 patients, average age=6.2). The results were compared with those of two other methods: the Vulpius group and the Z-lengthening group. The corrected dorsiflexion angle of the ankle at a subsequent 2-year follow-up of the mesh ATL and Vulpius groups matched (25.5±3.0 and 27.1±3.5°, respectively), whereas that of the Z-lengthening group was higher (33.9±3.8°). Nevertheless, statistics of the timing of each patient's readiness to begin rehabilitation and walking as well as gaining better stability for running and one-legged hopping indicated that the mesh ATL group recovered significantly quicker than the Vulpius and Z-lengthening groups. The mesh ATL procedure achieves a successful correction of the equinus deformity in spastic cerebral palsy comparable with that of the Vulpius procedure, with the advantage of preserving the gastrocnemius without a complete section. This confers greater antigravity stability and quicker recovery in patients.

The Baumann procedure to correct equinus gait in children with diplegic cerebral palsy

Although equinus gait is the most common abnormality in children with spastic cerebral palsy (CP) there is no consistency in recommendations for treatment, and evidence for best practice is lacking. The Baumann procedure allows selective fractional lengthening of the gastrocnemii and soleus muscles but the long-term outcome is not known. We followed a group of 18 children (21 limbs) with diplegic CP for ten years using three-dimensional instrumented gait analysis. The kinematic parameters of the ankle joint improved significantly following this procedure and were maintained until the end of follow-up. We observed a normalisation of the timing of the key kinematic and kinetic parameters, and an increase in the maximum generation of power of the ankle. There was a low rate of overcorrection (9.5%, n = 2), and a rate of recurrent equinus similar to that found with other techniques (23.8%, n = 5).

As the procedure does not impair the muscle architecture, and allows for selective correction of the contracted gastrocnemii and soleus, it may be recommended as the preferred method for correction of a mild fixed equinus deformity.

Long-term results after gastrocnemius-soleus intramuscular aponeurotic recession as a part of multilevel surgery in spastic diplegic cerebral palsy

BACKGROUND

Equinus of the foot at the ankle is one of the most common deformities in patients with spastic diplegic cerebral palsy, leading to gait disturbances and secondary deformities. During single-event multilevel surgery, equinus is commonly corrected by calf muscle lengthening, such as gastrocnemius-soleus intramuscular aponeurotic recession. Various studies have described satisfactory short-term results after gastrocnemius-soleus intramuscular aponeurotic recession. However, there is no evidence for maintenance of equinus correction because of the small and heterogeneous case series and short follow-up time previously reported.

METHODS

The present study provides long-term results after gastrocnemius-soleus intramuscular aponeurotic recession as a part of multilevel surgery for the treatment of equinus in forty-four patients with spastic diplegia who were able to walk (forty-eight legs had lengthening of the gastrocnemius and thirty-four legs had lengthening of the gastrocnemius and soleus). Standardized three-dimensional gait analysis and clinical examination were done preoperatively and at one year, a mean (and standard deviation) of 3 ± 1 years, and a mean of 9 ± 2 years after surgery.

RESULTS

Significant improvements in kinematic and kinetic ankle parameters on gait analysis as well as passive dorsiflexion in clinical examination were found one year after surgery. While there was a significant loss of passive dorsiflexion at the time of long-term follow-up, the improvements in gait analysis parameters were maintained. The endurance of gait improvements was accompanied by a persistent increase of dorsiflexor muscle strength without relevant loss of plantar flexor strength. Although it was not significant, there was a tendency for deterioration of gait analysis parameters over the nine years. The analysis of individual patterns showed recurrence of equinus at the ankle in 24% of the legs. Early-onset calcaneal gait was found one year after surgery in seven legs (9%), but without secondary crouch gait, and there was recovery at the time of the long-term follow-up. Late-onset calcaneal gait was seen at the time of long-term follow-up in eight legs (10%), of which four had an accompanying crouch gait.

CONCLUSIONS

Gastrocnemius-soleus intramuscular aponeurotic recession as a part of multilevel surgery leads to satisfactory correction of mild and moderate equinus deformity in children and adolescents with spastic diplegia without relevant risk for overcorrection and should be preferred over Achilles tendon lengthening to avoid overlengthening. The long-term results in the present study demonstrate that the improvements are long-lasting on average, but individual patients tend to develop recurrence and may need secondary gastrocnemius-soleus intramuscular aponeurotic recession.

Recurrence after surgery for equinus foot deformity in children with cerebral palsy: assessment of predisposing factors for recurrence in a long-term follow-up study

BACKGROUND

Despite the large number of studies on the recurrence after surgery for equinus foot deformity in cerebral palsy (CP) patients, only a few investigations have reported long-term recurrence rates. Furthermore, little is known on the interval between the recurrent surgeries and the factors that lead to early recurrence. This study aimed to assess the overall recurrence after surgery for equinus foot deformity in patients with CP and to assess the factors associated with recurrence. We also aimed to determine the predisposing factors for early recurrence.

METHODS

The medical records of 186 patients (308 feet) were reviewed in order to determine the recurrence after surgery for equinus foot deformity. The type of CP, type of surgery, age at surgery, functional mobility, passive dorsiflexion of the ankle at the last follow-up visit, and subsequent treatment were recorded. Kaplan-Meier survival analysis was employed, with the end point defined as reoperation.

RESULTS

The mean age at surgery was 6.8 ± 2.5 years (range, 2.2-13.1). With the mean follow-up period of 11.3 years (range, 7.2-17.7), the overall recurrence rate was 43.8%. The recurrence rate was highest among patients with hemiplegia (62.5%). The Kaplan-Meier survival without repeat surgery estimate was shown to be 88.6% at 5 years and 59.6% at 10 years. Among children with hemiplegia and diplegia, the younger children (≤8 years of age) showed a higher rate of recurrence compared with the older children (P = 0.04 and P = 0.01, respectively). In 41 feet (30.4%), reoperations were performed within 5 years after the primary surgery. Early recurrence was most prevalent among children with hemiplegia (50.0%). In children with diplegia and quadriplegia, the younger children underwent the secondary operation later than the older children (P = 0.04 and P = 0.02, respectively).

CONCLUSION

Recurrence after surgery for equinus foot deformity is common and the age at surgery has a significant influence on recurrence. Recurrence can occur at any age while the child is still growing; therefore, it is advised to follow those patients until they reach skeletal maturity.

LEVEL OF EVIDENCE

Level III, therapeutic study.

A multiple-task gait analysis approach: kinematic, kinetic and EMG reference data for healthy young and adult subjects

Standard clinical gait analysis protocols usually limit to test self-selected speed gait: this approach is generally valid and permits time and cost saving. Yet, the literature evidences suggest that some pathologies (especially at onset or subclinical level) may not primarily affect plain gait, but more demanding locomotor tasks. In the present study we therefore propose a multiple-task gait analysis protocol including: self-selected, increased and decreased speed gait; walking on toes; walking on heels; step ascending and step descending, and apply it to 40 healthy subjects (20 aged 6-17, 20 aged 22-72) thus building extensive reference data set. Published studies already report normative data for some of these tasks, but inhomogeneously (due to different collecting methods and biomechanical models, population characteristics, nature of data). We verify a good correlation between our results and those presented by Schwartz et al. (2008) [12] in their study providing extensive data on the effect of walking speed on the gait of healthy children. In discussing the results, the rationale and effectiveness of each task is confirmed, and we supply an electronic addendum with comprehensive kinematic, kinetic and electromyographic normative data for the considered population, along with a set of reference parameters and related statistical analysis, as a premise for further applications on pathological subjects.

Achilles tendon length and medial gastrocnemius architecture in children with cerebral palsy and equinus gait

BACKGROUND

The aim of this study was to examine both the tendon and muscle components of the medial gastrocnemius muscle-tendon unit in children with cerebral palsy (CP) and equinus gait, with or without contracture. We also examined a small number of children who had undergone prior surgical lengthening of the triceps surae to address equinus contracture.

METHODS

Ultrasound was used to measure Achilles tendon length and muscle-tendon architectural parameters in children of ages 5 to 12 years. Muscle and tendon parameters were compared among 4 groups: Control group (N=40 limbs from 21 typically developing children), Static Equinus group (N=23 limbs from 15 children with CP and equinus contracture), Dynamic Equinus group (N=12 limbs from 7 children with CP and equinus gait without contracture), and Prior Surgery group (N=10 limbs from 6 children with CP who had prior gastrocnemius recession or tendo-achilles lengthening). The groups were compared using analysis of variance and Scheffe post hoc tests.

RESULTS

The CP groups had longer Achilles tendons and shorter muscle bellies than the Control group (P<0.001). Normalized tendon length was also longer in the Prior Surgery group compared with the Static Equinus group (P<0.001). The Prior Surgery group had larger pennation angles than the CP groups (P< or =0.009) and tended to have shorter muscle fascicle lengths (P< or =0.005 compared with Control and Static Equinus, P=0.08 compared with Dynamic Equinus). Similar results were observed for pennation angles and normalized muscle fascicle lengths throughout the range of motion.

CONCLUSIONS

Children with spastic CP and equinus gait have longer-than-normal Achilles tendons and shorter-than-normal muscle bellies. These characteristics are observed even in children with dynamic equinus, before contracture has developed. Surgery further lengthens the tendon, restoring dorsiflexion but not normal muscle-tendon architecture. These architectural features likely affect function, possibly contributing to functional deficits such as plantarflexor weakness after surgery.

LEVEL OF EVIDENCE

Level II, prospective comparative study.

Management of the knee in spastic diplegia: what is the dose?

This article discusses the sagittal gait patterns in children with spastic diplegia, with an emphasis on the knee, as well as the concept of the "dose" of surgery that is required to correct different gait pathologies. The authors list the various interventions in the order of their increasing dose. The concept of dose is useful in the consideration of the management of knee dysfunction.

Surgical correction of equinus deformity in children with cerebral palsy: a systematic review

PURPOSE

Equinus is the most common deformity in cerebral palsy. However, despite the large volume of published studies, there are poor levels of evidence to support surgical intervention. This study was undertaken to examine the current evidence base for the surgical management of equinus deformity in cerebral palsy.

METHODS

A systematic review of the literature using "equinus deformity", "cerebral palsy" and "orthopaedic surgery" generated 49 articles. After applying inclusion and exclusion criteria, 35 articles remained. The Oxford Centre for Evidence-Based Medicine (CEBM) levels of evidence and the Methodological Index for Non-Randomized Studies (MINORS) were used to grade the articles.

RESULTS

Studies ranged in sample size from 9 to 156 subjects, with an average of 38 subjects. The mean age of subjects at index surgery ranged from 5 to 19 years. Nineteen studies used instrumented gait analysis, with an average follow-up of 2.8 years. Seven studies reported that a younger age at index surgery was associated with an increased risk of recurrent equinus. The average rate of calcaneus in hemiplegic children was 1% and it was 15% in those with spastic diplegia. Most studies were level 4 quality of evidence, leading to, at best, only grade C recommendation.

CONCLUSIONS

Cerebral palsy subtype (hemiplegia versus diplegia) and age at index surgery were the two most important variables for determining the outcome of surgery for equinus deformity in cerebral palsy. Despite the great emphasis on differences in surgical procedures, there was less evidence to support the type of operation in relation to outcome.

Development of calcaneal gait without prior triceps surae lengthening: an examination of predictive factors

BACKGROUND

Although equinus is more common in cerebral palsy (CP), the prevalence of calcaneal gait (CG) has been reported at more than 30% among patients with CP, even in the absence of prior surgical intervention. The goal of this study was to identify patient characteristics predictive of the development of CG in patients without prior triceps surae lengthening.

METHODS

Gait data were reviewed for 58 participants with bilateral involvement owing to CP (116 limbs) who had 2 gait analysis tests with no triceps surae lengthening between tests. None of the patients exhibited CG at the initial gait study. Patients were grouped according to whether or not they exhibited CG patterns at the second test. Factors potentially predictive of calcaneal gait patterns were compared statistically between groups.

RESULTS

CG was shown by 24/116 extremities (21%) at the second study. The CG group experienced greater increase in body weight and body mass index between tests (P=0.006 and 0.03 respectively). Passive dorsiflexion range with the knee flexed was significantly greater in the CG group (P=0.008). The CG group also showed a tendency toward greater plantarflexor weakness, although this only approached statistical significance (P=0.08) likely owing to small sample size. Age, CP subtype, time to follow-up, hamstring range, selective motor control, and gross motor functional level were not predictive.

CONCLUSIONS

Patients who undergo (or have potential to undergo) significant weight gain, and have tendencies toward excessive passive dorsiflexion with the knee flexed may be at risk for development of CG over time. In such patients, treatment regimens should include therapy to maintain or improve plantarflexor strength, and methods to prevent overstretching the plantarflexors. Nonsurgical treatments for triceps surae contractures, such as serial casting, may be preferable, to avoid hastening development of calcaneal crouch gait over time.

LEVEL OF EVIDENCE

Prognostic study---Level III (case-control).

Outcomes of gastrocnemius-soleus complex lengthening for isolated equinus contracture in children with cerebral palsy

BACKGROUND

The goal of the gastrocnemius-soleus complex (GSC) lengthenings in children with cerebral palsy (CP) is to achieve a plantigrade foot and normalize kinematics during gait. The study purpose was to evaluate the results of GSC lengthening for isolated equinus contracture in individuals with CP. It was hypothesized that GSC lengthenings would normalize passive ankle range of motion, kinematic, kinetic, and temporal spatial parameters.

METHODS

Gait data from 15 able-bodied participants from the laboratory normal database and passive range of motion, kinematic, kinetic, and temporal spatial gait parameters, and oxygen cost were collected and analyzed for 27 individuals with CP (36 limbs) with isolated equinus contracture who received GSC lengthenings. Data were compared between preoperative and postoperative assessments.

RESULTS

Mean age at baseline was 11.4 years (+/-3.2 y). Mean time between surgery and postoperative gait analysis was 1.3 years (+/-0.3 y). Passive range of motion measurements were obtained. Kinematic and kinetic data for the hip, knee and ankle, and temporal spatial parameters were obtained from a representative gait trial preoperatively and postoperatively. Paired t tests (P<0.05) determined whether preoperative data differed from postoperative data or from able-bodied data. The passive range of motion at the ankle was improved and normalized postoperatively. Ankle kinematics normalized without compensatory changes occurring at the knee or hip kinematics. Ankle moments and powers become more normal but did not completely normalize. Kinematics and kinetics of the hip and knee were not adversely affected. No changes in the temporal spatial data or oxygen cost occurred postoperatively.

CONCLUSIONS

These data support the finding that with appropriate patient selection isolated GSC lengthening does not result in overcorrection.

LEVEL OF EVIDENCE

Retrospective comparative study; level 3.

The relation of triceps surae surgical lengthening and crouch gait in patients with cerebral palsy

To investigate the effect of earlier triceps surae (TS) surgical lengthening at knee kinematics in the stance phase in patients with cerebral palsy (CP). One thousand and thirty-nine participants from an eligible total of 1750 children with CP were referred to gait analysis laboratory from January 2000 to April 2007. Inclusion criteria were the diagnosis of diparetic spastic CP levels I to III (GMFCS) and complete kinematics documentation. Patients with an asymmetrical knee pattern at kinematics and with different types of TS management among sides were excluded. The patients were divided into two groups according to the mean minimum knee flexion (MMKF) in stance phase: group A (n=253) MMKF > or =30 degrees and group B (n=786) MMKF less than 30 degrees . For each group, the occurrence of following procedures for TS in the past: (i) earlier surgery, (ii) gastrocnemius lengthening (zone I), (iii) gastrocnemius and soleus lengthening (zone II), and (iv) calcaneous tendon lengthening (zone III), was investigated. A chi test was applied to check if the number of procedures performed was different between groups. The level of significance was defined as P value of less than 0.05. The number of patients with no earlier surgeries at TS was higher in group B (51.8%) than in group A (39.1%), and this difference was significant (P<0.01). In addition, the number of procedures at the calcaneous tendon was more elevated in group A (36.8%) than in group B (27%), and this finding was statistically significant as well (P<0.02). The percentage of surgical lengthening at zones I and II was very similar between the groups A and B. This study has shown that patients without earlier surgical procedures at TS are more susceptible to reach better extension of the knees in the stance phase. Patients in a crouch gait had a higher number of calcaneous tendon lengthening performed in the past than patients with a more normal knee extension in the stance phase.

Static and dynamic gait parameters before and after multilevel soft tissue surgery in ambulating children with cerebral palsy

BACKGROUND

Recent studies have questioned the efficacy of releasing hip flexion contractures and the resulting ankle position after tendoachilles lengthening in ambulating children with cerebral palsy (CP).

METHODS

Twenty-three ambulatory children with CP underwent 96 soft tissue-lengthening procedures without bony surgery. Preoperative and postoperative clinical and computerized gait data were reviewed.

RESULTS

Static contractures improved reliably, with improvements in all areas measured, including hip flexion contracture (14 degree improvement), hip abduction (19 degree improvement), popliteal angle (26 degree improvement), and ankle dorsiflexion (11 degree improvement). The changes in computerized gait data were less uniform. The knees showed significant benefits, as evidenced by improved maximal knee extension in stance phase (37.3 degree preop and 19.9 degree postop) and at initial contact (51.6 degree preop and 34.8 degree postop). At the hip, a statistically significant improvement was only seen in maximum hip extension in stance phase (minimum hip flexion), and the magnitude of this change was only 4.6 degree (15.3 to 10.7 degree). There were no significant changes at the pelvis. At the ankle, the tendency was toward calcaneal gait after Achilles tendon lengthening, with excessive dorsiflexion seen both in stance (17.3 degree) and at toe off (-6.9 degree). Tempero-spatial parameters showed improved stride length, but no significant changes in gait velocity or cadence.

DISCUSSION

The persistence of crouch postoperatively, though improved, likely limited the potential changes in hip kinematics. As this study excluded patients undergoing osseous surgery, it is possible that lever arm dysfunction may have contributed to the ongoing crouch. The results of this study suggest that static contractures and knee kinematics improve reliably after soft tissue surgery in children with CP, but that caution must be exercised when considering heel cord lengthening in these children.

LEVEL OF EVIDENCE

Therapeutic level II. See Instructions to Authors for a complete description of levels of evidence.

Calf muscle-tendon lengths before and after Tendo-Achilles lengthenings and gastrocnemius lengthenings for equinus in cerebral palsy and idiopathic toe walking

The calf muscle-tendon lengths in children exhibiting equinus gait in two clinical populations, cerebral palsy (CP) and idiopathic toe walking (ITW), were examined to compare the effects of diagnosis and two different surgical procedures, Tendo-Achilles lengthening (TAL) versus Vulpius procedure (VP) gastrocnemius recession. Pre- and post-surgical gait data were obtained from 38 subjects (58 limbs) and 38 age-matched controls. Peak muscle-tendon lengths increased following surgery in 84% of limbs. For medial gastrocnemius (MGAS) and lateral gastrocnemius (LGAS) in stance, muscle-tendon lengths increased significantly following TAL surgeries but were not significantly different pre- and post-VP surgeries. For soleus (SOL) (swing and stance) and MGAS and LGAS (swing), muscle-tendon lengths increased significantly following both TAL and VP surgeries. Pre-operatively, muscle-tendon lengths were significantly shorter for the TAL group compared to the VP group; however, post-operatively the lengths were not significantly different between the surgeries. There were no significant differences between CP and ITW patients or indications that the surgery affected the groups differently. The change in length following surgery was well correlated to the subjects' initial muscle-tendon length.

Local and distant effects of isolated calf muscle lengthening in children with cerebral palsy and equinus gait

PURPOSE

The purpose was to assess the local and distant effects of isolated calf muscle lengthening in ambulant children with cerebral palsy.

METHODS

The study included fifteen ambulant children with cerebral palsy (nine with diplegia and six with hemiplegia), average age 8.8 years, Gross Motor Function Classification System (GMFCS) level I and II. None of the children had previously undergone orthopaedic surgery, apart from one child who had tendo-achilles lengthening (TAL) nine years earlier. All the children underwent pre and post-operative clinical examination and three-dimensional gait analysis (gait analysis). Twenty calf muscle lengthenings were performed, ten TAL and ten gastrocnemius recessions (GR).

RESULTS

Post-operative ankle kinematics showed significant improvements in all parameters. Ankle power during push-off increased, but only significantly after TAL. Only one limb (5%) was over-corrected. Four limbs (20%) were under-corrected and one of these limbs remained in mild equinus position in stance. There was one recurrent equinus (5%) during the follow-up period of three years (range: 13-55 months). Distant effects on joints and segments were more marked in diplegia than in hemiplegia. Ten of 17 kinematic parameters distant from the ankle joint improved significant post-operatively when the preoperative values were 1SD below or above the mean of the normal material. There was no significant deterioration in any of the measured parameters.

CONCLUSION

The improvement in ankle kinematics and kinetics supported the experience of other studies. The distant effects, which have previously not been evaluated in three planes, showed improvement in several kinematic parameters indicating that additional surgery in selected patients could be abandoned or delayed.

Evaluating interventions to improve gait in cerebral palsy: a meta-analysis of spatiotemporal measures

A number of interventions to improve gait in individuals with cerebral palsy (CP) have been reported in the literature. The aim of this study was to perform a meta-analysis of these studies to determine the overall efficacy of these interventions. Effect sizes (Hedge's g) for spatiotemporal measures of gait (velocity, cadence, stride length) pre- and postintervention were analyzed. Sixty-three studies were included, and the overall effect size was statistically significant for both fixed effects and random models. Types of interventions were grouped into spasticity treatments, orthopedic (bony and soft tissue) surgery, lower extremity orthoses, or 'other'. When the data were analyzed in subgroups by type of intervention, each intervention had a statistically significant effect size with the exception of the 'other'. More importantly, the present study indicates the need to address participant inclusion criteria and power analysis more adequately in future research studies of interventions to improve gait in CP.

Postoperative gait velocity and mean knee flexion in stance of ambulatory children with spastic diplegia four years or more after multilevel surgery

Factors associated with longer-term outcomes of multilevel orthopaedic surgery in ambulatory children with cerebral palsy using a multivariate approach were evaluated using a retrospective pretest-posttest design. The population included 20 ambulatory children with spastic diplegia who had undergone multilevel orthopaedic surgery with a minimum of 4-year interval between a preoperative and a postoperative gait assessment. Multiple regression analysis was used to identify factors associated with postoperative velocity and mean knee flexion in stance. Independent variables included in the regression models were velocity, mean knee flexion in stance, age at preoperative evaluation, Gross Motor Function Classification System level, use of ankle-foot orthoses, leg length, age-adjusted body mass index, number of surgical procedures, and range of motion of hip and knee. Children who demonstrated faster postoperative gait velocity 4 years or more after surgery were younger at the time of initial evaluation, had undergone fewer surgical procedures, had faster preoperative gait velocity, used ankle-foot orthoses postoperatively, and had increased hip extension range of motion postoperatively (R = 0.55). Children who demonstrated greater knee flexion in stance 4 years or more after surgery had undergone more surgical procedures, greater postoperative popliteal angle, and less knee extension range of motion (R = 0.73). This study demonstrates the usefulness of a multivariate approach toward understanding and predicting outcomes. The results of this study will provide clinicians and researchers more information about those factors associated with maintained improvements in the longer term and may be useful for treatment planning.

Evans calcaneal lengthening procedure for spastic flexible flatfoot in 32 patients (46 feet) with a followup of 3 to 9 years

BACKGROUND

The purposes of this study were to evaluate the outcome of calcaneal lengthening in severe pediatric flexible flatfoot deformities of spastic origin and to determine the necessity of additional procedures.

METHODS

In a prospective study, 32 patients (46 feet) were evaluated clinically and radiologically. The mean age of patients was 11 (range 4 to 22) years. The mean period of followup was 66 (range 36 to 108) months.

RESULTS

Additional soft-tissue procedures (Strayer procedure, peroneus lengthening, reefing medial capsule) were performed in 39 of 46 feet; other bony procedures were performed in eight. Among the 46 feet, 11 outcomes were classified as excellent, 19 as good, nine as fair, and seven as poor. Poor outcome was related to overcorrection in three and deformity relapse in four. Calcaneocuboid subluxation was seen in nine feet. Radiographic evaluation demonstrated an improvement of all parameters determined.

CONCLUSION

The Evans procedure is effective for the correction of severe, flexible flatfoot deformity in children with cerebral palsy in the short and mid term. Additional soft-tissue procedures frequently are required. However, correction of this multiplanar deformity predominantly occurs in the forefoot abduction component of the deformity, and the concomitant naviculocuneiform sag remains uncorrected. Despite successful outcomes, overcorrection and undercorrection remains a problem of clinical relevance.

Kinematic and kinetic evaluation of the ankle joint before and after tendo achilles lengthening in patients with spastic diplegia

Fourteen patients, at a mean age of 9.1 years (range 4.1-16.6 years), who had spastic diplegic cerebral palsy were evaluated before and after tendo Achilles lengthening (TAL). Follow-up (by gait analysis) after TAL ranged from 8 to 30 months. A Vicon motion analysis system with six CCD cameras and two AMTI force plates provided three-dimensional measurements of joint motion and moments. The TAL procedure resulted in normal passive dorsiflexion of the ankle joint with the knee at 0 degrees of extension and 90 degrees of flexion, reduced plantarflexion during swing phase, and reduced premature plantarflexor moment. However, 10 degrees greater than normal dorsiflexion of the ankle joint during mid-stance phase was indicative of a mild calcaneal gait pattern. The TAL procedure improved lower extremity function as documented by both kinematic and kinetic analysis in cerebral palsy.

Das operative Management bei spastischen Fu�deformit�ten

Any surgical treatment of spastic foot deformities must be preceded by an exact preoperative analysis of every aspect of the deformity and its functional consequences. The goals of surgical treatment are correction of the deformity, reestablishment of the stability of the foot and preservation of functionally important ranges of motion and muscle strength. These goals can usually be achieved only by a package of several simultaneous procedures. The foot must never be treated in isolation. Proximal joints have to be considered as well as the opposite side, because a plantigrade position of the foot is only possible when the leg is straight. Any postoperative evaluation must also take into account the proximal joints and the opposite leg in unilateral cases. The mere static evaluation of the postoperative results by reporting clinical and radiographic values should be supplemented by dynamic measurements which allow more insight into the functional results.

Treatment of spastic diplegia in patients with cerebral palsy: Part II

This review article describes the evaluation, treatment options, and expected outcomes for many of the common deformities of the lower extremities in patients with cerebral palsy. The evaluation tools including gait analysis will be applied to each specific deformity. Dynamic components are addressed with spasticity management and appropriate muscle and tendon procedures. The static components are treated with bony procedures, including various osteotomies and arthrodesis, incorporating biomechanical principles.

Outcome of gastrocnemius recession and tendo-achilles lengthening in ambulatory children with cerebral palsy

Preoperative and postoperative gait analysis data were retrospectively studied for 54 children with cerebral palsy who had undergone either gastrocnemius recession (GR) or tendo-achilles lengthening (TAL) as part of multi-level surgery. Decision-making between GR and TAL was based on the Silfverskiöld test. The TAL group had greater equinus preoperatively than the GR group. Both groups showed significant improvement in static and dynamic dorsiflexion and in outcome measured by a modified Physician Rating Scale (PRS) postoperatively. Calf spasticity decreased and push-off power increased after GR. Both GR and TAL are effective in appropriately selected patients. However, a potential for over- and under-correction with both GR and TAL was demonstrated.

A computational model for the adaptation of muscle and tendon length to average muscle length and minimum tendon strain

This paper hypothesizes that average muscle length and minimum tendon strain govern muscle and tendon length adaptation in all situations. A model has been implemented to test this hypothesis, and simulations have been performed for normal development, bone lengthening, immobilization, and retinacular release experiments in young and adult animals. The simulation results predict that both muscle and tendon lengthen during normal development, with the rate of tendon growth slowing faster than the rate of muscle growth. The results also predict that muscle length increases during bone lengthening in both young and adult animals, while tendon length increases only in young animals. For immobilization in adult animals, the results predict that muscle length increases when the muscle is immobilized in a lengthened position and decreases when the muscle is immobilized in a shortened position with no change in tendon length. For immobilization in young animals, the results predict reduced muscle growth and increased tendon growth regardless of immobilization position. Finally, the simulations predict that retinacular release which increases excursion of the musculotendinous unit leads to increased muscle length with decreased tendon length in young animals and decreased muscle length with no change in tendon length in adult animals. These simulation results are consistent with experimental findings reported in the literature by other investigators. This suggests that average muscle length and minimum tendon strain may represent general principles that govern muscle and tendon length adaptation.

Lengthening the Achilles tendon for the treatment of diabetic plantar forefoot ulceration

The accepted hallmarks of care for plantar forefoot ulceration are meticulous wound care, nutrition, management of infection, and non-weight bearing of the ulcerative area. Tendo-Achilles lengthening is crucial in healing these ulcerations when it is determined that the Achilles tendon is one of the main biomechanical stresses that led to the ulceration. The Silfverskiold test helps determine whether a percutaneous lengthening or gastrocnemius recession is called for. A gastrocnemius recession is the safer operation because it does not carry the postoperative risk of overlengthening or rupture, calcaneal gait, and subsequent plantar heel ulceration, but gastrocnemius recession carries a higher late recurrence rate of late plantar forefoot reulceration (16%). A more permanent result can be achieved with percutaneous tendo-Achilles lengthening, although one assumes the associated risk of overlengthening the tendo-Achilles, calcaneal gait, and the difficult-to-treat plantar calcaneal ulceration. It is crucial to address other biomechanical abnormalities that may have contributed to the specific plantar ulceration, such as hammer toe, prominent plantar metatarsal head, prominent sesamoids, and long metatarsal. In addition, the patient should be placed in proper footwear, which at the minimum includes orthoses but may include specialized accommodative shoe wear. Failure to include these adjunctive procedures to Achilles tendon lengthening may prevent healing or hasten ulcer recurrence. Future studies will be directed toward determining the roles of prophylactic Achilles tendon lengthening preventing equinovarus deformities, possible plantar foot ulceration, and Charcot collapse.

The effect of tibial torsion on the dynamic function of the soleus during gait

An induced acceleration analysis (IAA) model was used to investigate the effect of tibial torsion on the ability of the soleus to support and propel the body during gait. The IAA approach is well suited for this study because it allows soleus action to be quantified in the presence of varying amounts of tibial torsion, while other factors such as body configuration and muscle activation are held constant. The results of the analysis showed that excess tibial torsion shifts the induced knee joint accelerations toward flexion, valgus and external rotation, and diminishes body center-of-mass support and propulsion. This analysis supports the concept that bony mal-alignment can lead to 'lever arm dysfunction'. The objective data correlate with previous clinical observations related to valgus stress, crouch and the role of the soleus in level walking. The IAA model provides a tool for examining various aspects of abnormal gait independently and quantitatively.

Rehabilitation of spasticity and related problems in childhood cerebral palsy

Spasticity is one part of the upper motor neuron syndrome, but it is a widespread problem in cerebral palsy; it is debilitating, affects function and can lead to musculoskeletal complications. Significant advances have occurred in antispasticity management (and related musculoskeletal problems) in children with cerebral palsy during the past 5-10 years. Botulinum toxin A has been the most outstanding treatment advance; it is relatively long-lasting, easy to administer, reversible, has a favourable side-effect profile and is highly useful for focal spasticity. There is an emerging role for intrathecal baclofen in Australia. Despite being available and practised in North America for years, selective dorsal rhizotomy has not been popular in Australia. The use of orthopaedic surgery has significantly altered in recent years. There is still a place for oral drug treatment, including some newer agents and the potential for combination treatment with other modalities. The role of physical therapy in defining disability, assessing function, undertaking biomechanical assessment and providing mobility aids/casting/orthoses and motor training/stretching exercises is critical for the success of medical and surgical interventions. From an Australian perspective, the purpose of the present review is to provide a critical review of therapies available for spasticity associated with childhood cerebral palsy.

Current evidence for the use of botulinum toxin type A in the management of children with cerebral palsy: a systematic review

Management of children with cerebral palsy (CP) is the focus of considerable resources in many countries, so that evaluation of the efficacy for new and established treatments is imperative. Botulinum toxin type A (BTX-A) is a relatively new method of spasticity management in children with cerebral palsy. It has been the focus of extensive research since its application to cerebral palsy 10 years ago. In a systematic review relating to the management of the lower limb in cerebral palsy 156 papers were identified. These were categorized according to Sackett and the World Health Organisation International Classification of Impairments, Disabilities and Handicaps model. We identified 10 randomized trials evaluating the use of BTX-A in the lower limb in children with cerebral palsy in a systematic review. A meta-analysis showed the pooled risk difference between BTX-A and placebo in three trials was 0.25 (95% CI 0.13, 0.37) and 0.23 (95% CI -0.06, 0.53) for two trials of BTX-A and casting using the physicians rating scale. These represent moderate treatment effects that are dosage-dependent. Outcomes were also compared for function in five studies. The type of evidence for BTX-A was graded by each treatment indication and directions for future research were then drawn from the available evidence.

Hip locomotion mechanisms in cerebral palsy crouch gait

The purpose of this study was to evaluate three defined locomotion patterns in cerebral palsy gait using computerised gait analysis. Ambulant diplegic children who had no previous surgery were included in the study and were divided into two groups: one group consisted of children having a crouch gait, and the other group did not have the crouch pattern of gait. An age-matched group of normal children served as the control group. Locomotion patterns studied were the hip hike, propulsive function of the hip extensors, and pseudo-adduction. A statistical analysis was performed between the groups, using defined parameters. The mechanism of hip hike was not utilised by any of the groups. Both groups of diplegic children showed power generation at the hip beginning in the first double support phase of the gait cycle and continuing in the first half of single limb support, while in the normals this was only in the first half of single limb support. Both the groups of diplegic children showed significantly more internal rotation in the first half of stance as compared to the group of normal children; the degree of hip adduction was the same in all the groups. Thus diplegic children had pseudo-adduction.

Fixed and dynamic equinus in cerebral palsy: evaluation of ankle function after multilevel surgery

Multilevel surgery for gait improvement was performed on 29 ambulatory children with diplegic cerebral palsy. Patients were divided into two groups based on the presence of dynamic equinus (12 cases) and fixed equinus deformity (17 cases). Dynamic equinus deformities were not corrected surgically, and fixed deformities were corrected by intramuscular gastrosoleus lengthening. Ankle function was evaluated by clinical examination and gait analysis before surgery and a minimum of 3 years after surgery. Positive changes in ankle function were observed in both the groups. Conservative management of dynamic equinus deformities resulted in significant improvements in ankle function. Intramuscular lengthening of fixed equinus deformities does not cause a weakening of the muscle and improves static and dynamic function of the ankle.

Reflections on clinical gait analysis

Clinical gait analysis allows the measurement and assessment of walking biomechanics, which facilitates the identification of abnormal characteristics and the recommendation of treatment alternatives. The predominant methods for this analysis currently include the tracking of external markers placed on the patient, the monitoring of patient/ground interaction (e.g. ground reaction forces), and the recording of muscle electromyographic (EMG) activity, all during gait. These data allow the computation of stride and temporal parameters, joint/segment kinematics, joint kinetics, and EMG plots that are used to gain a better understanding of a patient's walking difficulties. Gait interpretation involves a systemic evaluation of each of these types of data, noting both corroborating and conflicting information while identifying functionally significant deviations from the normal. Understanding the etiology of these abnormalities allows the formulation of a treatment plan that may involve physical therapy, bracing, and/or surgery. This process is challenging because of the complexity of the motion, neuromuscular involvement of the patient (e.g. dynamic spasticity), variability of treatment outcome, and on occasion, uncertainty about the quality of the gait data. The experience of the interpretation team with respect to gait biomechanics, a particular patient population, and the effectiveness of different treatment modalities is the principal determinant of the success of this approach. The clinical gait analysis process continues to evolve positively. It has become more comprehensive and meaningful because of an improved understanding of normal gait biomechanics and more rigorous data collection/reduction protocols that complement accumulated clinically relevant experience.