Mark L. McMulkin

Correlation of static to dynamic measures of lower extremity range of motion in cerebral palsy and control populations.

The question addressed in this study was whether static measurements of hip, knee, and ankle range of motion correlate to dynamic measurements of hip and knee function during gait. Range-of-motion measures of the lower extremities taken during physical examination (static variables) were recorded on 80 adolescents with cerebral palsy and 30 adolescent normal controls. Kinematic measurements collected during gait analysis (dynamic variables) were recorded on the same patients and controls. Results indicated no correlation greater than r = 0.50 (R2 < 0.25) between any static and dynamic variable for either group--cerebral palsy patients or controls. The lack of good correlation of these measures indicates static physical examination variables such as popliteal angle and straight-leg raise are not good predictors of dynamic gait, such as knee-extension and hip-flexion variables measured during ambulation in controls or cerebral palsy populations.

Comprehensive outcomes of surgically treated idiopathic toe walkers.

Abstract: The treatment of idiopathic toe walking in children can include surgical lengthening of the gastrocnemius/soleus complex after conservative options have been ineffective. Previous outcome reports of surgery for idiopathic toe walkers have largely been limited to assessing the sagittal plane motion of dorsiflexion/plantar flexion with minimal quantitative preoperative and postoperative analysis. The purpose of this study was to comprehensively assess the outcome of idiopathic toe walkers that had been treated surgically. Fourteen children seen in our motion analysis laboratory that underwent gastrocnemius or tendo-Achilles lengthening for idiopathic toe walking were retrospectively reviewed. Preoperatively, this group had significantly greater anterior pelvic tilt than normal, decreased peak knee flexion in swing, greater external foot progression, and the expected increased plantar flexion (P < 0.01). Postoperatively, anterior pelvic tilt decreased by a mean of about 4 degrees (P < 0.01), only for the group that had tendo-Achilles lengthening because the gastrocnemius group was close to normal preoperatively, and peak knee flexion normalized. The foot progression angle of this group did not change from preoperative values and remained significantly more external than normal, although dorsiflexion in stance significantly improved after surgery (indicating the goal of the surgery was achieved). Increased external foot progression in idiopathic toe walkers is apparently due to increased external tibial torsion and/or external hip rotation but was unaffected by gastrocnemius/soleus surgical lengthening. Significant improvement occurred on an overall index of gait variables, indicating surgery can be an effective treatment of idiopathic toe walkers.

Effect of Bench Height on Sit-to-Stand in Children Without Disabilities and Children With Cerebral Palsy

OBJECTIVE To evaluate the effect of seat height on sit-to-stand (STS) in children with cerebral palsy (CP) and in children without disabilities. DESIGN A mixed design (subject type by seat height) with repeated measures for seat height. SETTING Motion analysis laboratory. PARTICIPANTS Ten children with mild CP (mean age, 10.9+/-2.7 y) and 10 children without disabilities (mean age, 8.7+/-2.4 y). INTERVENTIONS Kinematic and force measurements of STS were completed with 6 infrared cameras and 2 forceplates. MAIN OUTCOME MEASURES Phase duration of the STS movement, amplitude and timing of ground reaction forces, and maximum head velocity during the movement. RESULTS Children with CP took significantly longer to rise to standing (1.71 s) than children without disabilities (1.24 s) (F(1,18)=16.97). The extension phase of STS was also significantly longer for children with CP (.85 s) than for children without disabilities (.45 s) (F(1,18)=18.73). Seat height did not affect time to stand for either children with CP or children without disabilities (F(1,18)=2.82, P>.05). The duration of the extension phase, maximum horizontal and vertical velocity of the head, and maximum vertical ground reaction force were all significantly greater when children stood from the low bench height than from the higher bench height, although we found no significant differences by subject type for maximum horizontal and vertical head velocity or for maximum vertical ground reaction force. CONCLUSIONS Although children with CP were able to modify their motor programs for STS to accommodate changes in seat height as readily as nondisabled children, the speed with which they extended against gravity was slower; therefore, the total STS movement took longer for them to complete than for children without disabilities. Because the time to complete STS from the low and high bench did not differ, it would appear that time to ascend from sitting may be invariant and therefore be a motor control parameter for the STS movement.

The pediatric outcomes data collection instrument detects improvements for children with ambulatory cerebral palsy after orthopaedic intervention.

The purpose of this study was to assess whether the Pediatric Outcomes Data Collection Instrument (PODCI) was able to detect changes in function, as perceived by the parents of children and adolescents with cerebral palsy who had undergone lower limb soft tissue and/or bony surgeries. This was a retrospective study of 80 ambulatory patients who were seen in the motion laboratory and classified with the Gross Motor Functional Classification System (GMFCS). Significant changes (P < 0.05) were detected in the PODCI scores for upper extremity function, transfers and mobility, physical function and sports, and global function after surgery, by approximately 4% to 5%, whereas comfort (pain-free) did not significantly change. There was a significant difference in the PODCI scores preoperatively between GMFCS levels I, II, and III for upper extremity function, transfers and mobility, physical function and sports, and global function. Postoperative improvements were of equal magnitude for each GMFCS level. This suggests that the PODCI did not have a ceiling effect for high-functioning children. Age (±10 years) and surgery (soft tissue/soft tissue plus bony) were not significant factors for any of the subcategories preoperative to postoperative. In conclusion, the PODCI detected improvement as perceived by the parents in ambulatory children with cerebral palsy after lower-limb soft tissue and/or bony surgeries in 4 areas by a magnitude of approximately 4% to 5%.

Gait analysis outcomes of percutaneous medial hamstring tenotomies in children with cerebral palsy.

Background: Hamstring lengthening procedures are commonly performed on children with cerebral palsy (CP) to improve gait. The purpose of this study was to determine the efficacy of percutaneous hamstring tenotomy surgery for children with ambulatory CP. Methods: In this retrospective study, subjects were included if they had a diagnosis of CP and had computerized gait analysis data collected before and after surgery. Subjects were not included in the study if they had any open hamstring lengthening on the same side. Other concomitant lower extremity surgeries were not exclusionary. Short- and long-term follow-up groups were established: if the time from their surgery to their gait laboratory was less than 18 months, they were placed in the short-term follow-up group, and if the time from their surgery to their gait laboratory was greater than 18 months, they were placed in the long-term follow-up group. Results: The results demonstrated that for short- and long-term groups on preoperative to postoperative analysis, there was significantly improved knee extension at initial contact, increased velocity, increased stride length, improved overall gait as indicated by a decrease in a 16 variable multivariate index (Gillette Gait Index), and a decreased popliteal angle. For the short-term group only, additional significant findings included increased peak knee extension in stance and reduced plantar flexion at initial contact. The absolute values of peak knee extension in stance and plantar flexion at initial contact were equivalent at follow-up for the short- and long-term groups. Increased anterior pelvic tilt was also significant for the short-term follow-up group only. Conclusions: The findings of this study demonstrate that the minimally invasive technique of percutaneous hamstring tenotomy is effective in improving key dynamic gait parameters for individuals with CP for a short period, and these benefits are maintained in the long term. Level of Evidence: Level IV.

Intersite variations of the Gillette Gait Index

The Gillette Gait Index (GGI) is a tool used to measure pathologic gait severity and assess outcomes. The purpose of this study is to assess the variation in calculated GGI values with different sets of control data. Five able bodied control sets from four labs were used to establish the basis of the GGI. Gait data from three pediatric patients seen pre- and post-operatively at one lab and one adult control subject that visited each lab were input to calculate GGI values. Differences in underlying control data created large differences in computed GGI values for both pathologic and able bodied subjects. Initial pre-operative GGI values calculated for the three patients with cerebral palsy using different control data sets varied widely with differences as large as 1129 and had magnitudes of improvement differing by as much as 800 (or 21%). GGI value differences greater than 250 were determined from an able bodied control subject seen at each lab, both when examining a single trial with different control sets, and when examining different trials of the same individual collected from different labs using a single control set. These results highlight the importance of the underlying control set for establishing mean values and variance in the GGI and suggest that if GGI values are compared longitudinally or between sites these comparisons should be based on a single control dataset.

Distal Tibial Rotation Osteotomies Normalize Frontal Plane Knee Moments

BACKGROUND Torsional deformities of the lower extremity are common in children and are often corrected with rotational osteotomy. The effects of torsional abnormalities, and the effects of corrective osteotomy, are not well understood. A study of children with isolated idiopathic tibial torsional pathology undergoing a single corrective procedure may assist in understanding the biomechanics of torsional deformities and the effect of surgical correction. METHODS Preoperative and postoperative gait analyses were performed for eight subjects (eleven sides) with idiopathic excessive inward tibial torsion and ten subjects (fourteen sides) with excessive outward tibial torsion. Sagittal ankle and frontal knee moments were assessed and compared with those for age-matched controls. RESULTS Preoperatively, subjects exhibited abnormal frontal knee moments at push-off. Subjects with inward tibial torsion demonstrated excessive internal valgus moments, and subjects with outward tibial torsion demonstrated reduced internal valgus or relative internal varus moments compared with the control subjects. Ankle power was significantly reduced in the inward torsion group but not in the outward torsion group. Surgical correction of the torsional deformities normalized frontal plane knee moments in both inward and outward torsion groups and restored ankle power in the inward torsion group. CONCLUSIONS In the present study, excessive tibial torsion adversely affected frontal knee moments and was associated with other kinematic and kinetic abnormalities. Corrective osteotomies improved all variables studied here and restored many to the values found in the control group.

Outcomes of Orthopaedic Surgery With and Without an External Femoral Derotational Osteotomy in Children With Cerebral Palsy.

Background: Ambulatory children with cerebral palsy (CP) often present with multiple deviations in all planes including increased internal hip rotation during gait. Excessive femoral anteversion is a common cause of deviation managed surgically with an external femoral derotational osteotomy (FDO). The purpose of this study was to evaluate the gait and functional outcomes of a group of subjects with CP who underwent surgical intervention that included an FDO compared with a match group with indications of internal hip rotation that did not receive an FDO. Methods: For this retrospective study, subjects were identified from the Motion Analysis Laboratory database that had orthopaedic surgery including an FDO (FDO group). A control group was established from a chart review identifying subjects that had indications for an FDO, but did not have this surgery (No-FDO group). All subjects had preoperative and postoperative gait studies. Subjects categorized as Gross Motor Function Classification System (GMFCS) levels I and II in both FDO and No-FDO groups were combined for analysis. Subjects rated as GMFCS level III were analyzed separately. Preoperative to postoperative kinematic and kinetic variables, Gait Deviation Index, net oxygen cost, and PODCI scores were analyzed with paired t tests. Results: Typical sagittal plane kinematic variables improved significantly by equivalent magnitudes for both FDO and No-FDO groups (GMFCS I/II and III). Transverse plane improvements were only seen for the FDO group (GMFCS I/II and III). The Gait Deviation Index, an overall index of kinematics, improved by a significantly greater amount for the FDO group across GMFCS levels I/II and III. Net oxygen cost improved for both FDO and No-FDO for GMFCS I/II. PODCI scores improved for FDO and No-FDO in GMFCS I/II, but only the FDO group for GMFCS III. Conclusions: For children with CP, inclusion of an FDO in the surgical intervention, when indicated, resulted in improved outcomes. Overall gait kinematic improvements were significantly greater when an FDO was included in the surgical management. Level of Evidence: Level III—retrospective comparative study.

Application of the Gillette Gait Index, Gait Deviation Index and Gait Profile Score to multiple clinical pediatric populations.

Gait indices are now commonly used to assess overall pathology and outcomes from studies with instrumented gait analyses. There are differences in how these indices are calculated and therefore inherent differences in their sensitivities to detect changes or differences between groups. The purpose of the current study was to examine the three most commonly used gait indices, Gillette Gait Index (GGI), Gait Deviation Index (GDI), and Gait Profile Score (GPS), comparing the statistical sensitivity and the ability to make meaningful interpretations of the clinical results. In addition, the GDI*, a log transformed and scaled version of the GPS score which closely matches the GDI was examined. For seven previous or ongoing studies representing varying gait pathologies seen in clinical laboratories, the GGI, GDI, and GPS/GDI* were calculated retrospectively. The GDI and GPS/GDI* proved to be the most sensitive measures in assessing differences pre/post-treatment or from a control population. A power analysis revealed the GDI and GDI* to be the most sensitive statistical measures (lowest sample sizes required). Subjectively, the GDI and GDI* interpretation seemed to be the most intuitive measure for assessing clinical changes. However, the gait variable sub-scores of the GPS determined several statistical differences which were not previously noted and was the only index tool for quantifying the relative contributions of specific joints or planes of motion. The GGI did not offer any advantages over the other two indices.

Gross Motor Development in Babies With Treated Idiopathic Clubfoot

Purpose: To investigate the effect of treated clubfoot disorder on gross motor skill level measured by the Alberta Infant Motor Scale (AIMS). Methods: Fifty-two babies participated: 26 were treated for idiopathic clubfoot (12 with the Ponseti treatment method, 9 with the French physical therapy technique, and 5 with a combination of both methods); 26 were babies who were typically developing and without medical diagnoses. The AIMS was administered at 3-month intervals. Results: No significant differences in AIMS scores were found between the clubfoot and control groups at 3 and 6 months, but at 9 and 12 months the clubfoot group scored significantly lower. Babies who were typically developing were significantly more likely to be walking at 12 months than babies with clubfoot. Conclusions: Treated clubfoot was associated with a mild delay in attainment of gross motor skills at 9 and 12 months of age.