Suzanne E. Halliday

The Effect of Limb-Length Discrepancy on Gait*

We evaluated the gait of thirty-five neurologically normal children who had a limb-length discrepancy of the lower extremities that ranged from 0.8 to 15.8 per cent of the length of the long extremity (0.6 to 11.1 centimeters). The twenty-two boys and thirteen girls had an average age of thirteen years (range, eight to seventeen years). No patient had a substantial angular or rotational deformity of the lower extremities. We found no correlation between the actual discrepancy or the per cent discrepancy and any of the dependent kinematic or kinetic variables, including pelvic obliquity. Discrepancies of less than 3 per cent of the length of the long extremity were not associated with compensatory strategies. When a discrepancy was 5.5 per cent or more, more mechanical work was performed by the long extremity and there was a greater vertical displacement of the center of body mass. Clinically, this degree of discrepancy was manifested by the use of toe-walking as a compensatory strategy. Children who had less of a discrepancy were able to use a combination of compensatory strategies to normalize the mechanical work performed by the lower extremities.

Interobserver variability of gait analysis in patients with cerebral palsy.

In this study 11 ambulatory patients (mean 10.8 years) with spastic cerebral palsy were each evaluated with instrumented gait analysis at four different centers. After review of the data, each medical director chose from a list of treatment options. The average variability in static range of motion from physical examination ranged from 25° to 50°. Hip and knee sagittal motion had the best relative variability of 20° to 24%. Via gait analysis, the average variability in sagittal, coronal, and transverse plane kinematic motions averaged 12,° 7°, and 20°, respectively. Increased variability was noted in transverse (worst) to coronal and finally sagittal (best) plane motion. Only two mildly affected patients had similar, but not exact, treatment recommendations. The authors conclude that substantial variations in raw data exist when the same cerebral palsy patient is evaluated at different gait centers. These data do not yield the same treatment recommendations in the majority of patients.

Gait and Function After Intra-Articular Arthrodesis of the Hip in Adolescents*

Background: Patients who have had a hip arthrodesis have been reported to have pain in the back and the knee due to an altered gait. There is little information about the specific compensatory mechanisms that are adopted when walking. The purpose of this study was to objectively define gait adaptations after an arthrodesis of the hip and to correlate the kinematic findings with pain and other patient outcomes. Methods: Nine patients who had had an arthrodesis of the hip at an average age of thirteen years and five months (range, ten years and nine months to sixteen years and eleven months) were evaluated with gait analysis and muscle strength-testing and completed a questionnaire related to pain and function. The average duration of follow-up was eight years and ten months (range, two years and one month to thirteen years and ten months). The frequency of the postoperative visits varied. Seven patients were adults at the time of the study and were called back specifically for the study. Results: All patients had decreased cadence and step lengths. The kinematic findings included decreased dorsiflexion of the ipsilateral ankle, hyperextension of the ipsilateral knee during the stance phase, and a tendency toward increased genu valgum during gait. In normal gait, there is no genu varum or valgum during the stance phase. The patients had an average (and standard deviation) of 7 ± 4 degrees of genu valgum. Pelvic and lumbar motion in the sagittal plane was excessive in all patients. Strength-testing revealed clinically relevant weakness in the ipsilateral quadriceps in all patients, with a difference of more than 20 percent between the two extremities in six patients. The gastrocnemius-soleus muscle was stronger on the side with the fused hip in six patients. The questionnaire, designed by Harris in 1969 and completed by the patients at the time of the gait analysis, revealed back pain in seven patients. The questionnaire was administered only once. The functional outcome as measured with use of the same questionnaire worsened as the duration of follow-up increased. Conclusions: The gait analysis showed excessive motion in the lumbar spine and the ipsilateral knee in all nine patients. This abnormal motion led to pain as the duration of follow-up increased, and all patients who had been followed for four or more years after the arthrodesis complained of back pain. We hypothesized that excessive motion for an extended duration can lead to back pain. The preferred position of the hip for the arthrodesis was 20 to 25 degrees of flexion, neutral abduction-adduction, and neutral rotation.

Gait Abnormalities Following Slipped Capital Femoral Epiphysis

The authors evaluated 30 subjects with treated unilateral slipped capital femoral epiphysis and a range of severity from mild to severe to characterize gait and strength abnormalities using instrumented three-dimensional gait analysis and isokinetic muscle testing. For slip angles less than 30°, kinematic, kinetic, and strength variables were not significantly different from age- and weight-matched controls. For moderate to severe slips, as slip angle increased, passive hip flexion, hip abduction, and internal rotation in the flexed and extended positions decreased significantly. Persistent pelvic obliquity, medial lateral trunk sway, and trunk obliquity in stance increased, as did extension, adduction, and external rotation during gait. Gait velocity and step length decreased with increased amount of time spent in double limb stance. Hip abductor moment, hip extension moment, knee flexion moment, and ankle dorsiflexion moment were all decreased on the involved side. Hip and knee strength also decreased with increasing slip severity. All of these changes were present on the affected and to a lesser degree the unaffected side. Body center of mass translation or pelvic obliquity in mid-stance greater than one standard deviation above normal correlated well with the impression of compensated or uncompensated Trendelenburg gait.