James R. Gage

A gait analysis data collection and reduction technique

Abstract The clinical objective of the gait analysis laboratory, developed by United Technologies Corporation (Hartford, CT, USA) in 1980, at the Newington Childrens Hospital is to provide quantified assessments of human locomotion which assist in the orthopaedic management of various pediatric gait pathologies. The motion measurement system utilizes a video-based data collection strategy similar to commercially available systems for motion data collection. Anatomically aligned, passive, retroreflective markers placed on the subject are illuminated, detected, and stored in dedicated camera hardware while data are acquired from force platforms and EMG transducers. Three-dimensional marker position information is used to determine: (i) the orientation of segmentally-embedded coordinate systems, (ii) instantaneous joint center locations, and (iii) joint angles. Joint kinetics, i.e., moments and powers, may also be computed if valid force plate data are collected.

Three-dimensional lower extremity joint kinetics in normal pediatric gait

Gait analysis is becoming a more integral part of the decision-making process in treatment of children with neuromuscular problems. A normal reference, however, must be available for comparison when one makes decisions. We wished to develop a normal pediatric database for joint kinematics and kinetics which could then be used as a reference for clinical gait analysis. Thirty-one normal children underwent a complete gait analysis including calculations of three-dimensional joint kinematics and kinetics. The pediatric data were similar to that of normal adults.

Clinical determination of femoral anteversion. A comparison with established techniques.

We evaluated femoral anteversion preoperatively in fifty-nine patients (ninety-one hips), using a clinical method that we developed, Magilligan radiographs, and computed tomographic scans. These measurements were then compared with values for anteversion that were obtained intraoperatively. To determine femoral anteversion clinically, the patient was placed in the prone position and the maximum lateral trochanteric prominence was related to the degree of internal rotation of the hip. Compared with computed tomographic scanning and Magilligan radiographic determination, the clinically determined anteversion correlated most closely (to within 4 degrees) with the amount measured at the time of the operation. The clinical method was found to be superior to radiographic techniques for determination of the degree of femoral anteversion in children who have not had a previous operation about the hip.

Avascular Necrosis of the Capital Femoral Epiphysis as a Complication of Closed Reduction of Congenital Dislocation of the Hip: A Critical Review Of Twenty Years' Experience At Gillette Children's Hospital

In a retrospective study of 154 congenital dislocations of the hip treated by closed reduction with and without preliminary traction at Gillette Hospital during the period January 1, 1948, through December 31, 1967, the incidence of avascular necrosis was analyzed after follow-ups ranging from two to more than nineteen years. There were twenty-seven hips with complete necrosis and twenty-four with partial necrosis. Eight of the normal hips had shown Type-I changes previously described by Salter, Kostuik, and Dallas. An attempt was made to identify the factors responsible for avascular necrosis of the capital femoral epiphysis, either complete or partial. As a result of this study the following conclusions were reached: 1. The older the child is, the more frequent the complication of avascular necrosis, all other factors being equal. 2. There is a direct correlation between inadequate traction and the incidence of avascular necrosis of the femoral head. 3. There is a direct correlation between the Lorenz position and the incidence of avascular necrosis of the femoral head. 4. Avascular necrosis usually results in permanent deformity of the femoral head, but there is a spectrum of deformities which in all likelihood depend on the severity of the vascular insult. 5. A program of adequate traction, gentle reduction, and avoidance of the extreme Lorenz position reduced the incidence of total avascular necrosis from 34.8 per cent during the first five years of the study period to 4.5 per cent in the last five years. The incidence of partial necrosis, on the other hand, remained essentially the same.

Kinematic and kinetic evaluation of the ankle after lengthening of the gastrocnemius fascia in children with cerebral palsy.

Summary: The effect of surgical lengthening of the gastrocnemius fascia on ankle joint kinematics and kinetics during gait in patients with cerebral palsy (CP) was evaluated. Twenty independent ambulators (24 sides) were included in this retrospective study. The evaluation included clinical examination, calculation of joint kinematics and kinetics, and collection of surface electromyography (EMG) during gait. Postoperative improvements were noted in static heelcord range of motion (ROM), with an associated increase in dorsiflexion in stance and swing. Kinetic analysis showed a decrease in the abnormal energy generated around the ankle in midstance and a statistically significant increase in the energy generated in late stance for push-off.

Rectus femoris surgery in children with cerebral palsy. Part I: The effect of rectus femoris transfer location on knee motion.

Summary Rectus femoris transfer was performed in 78 children (105 sides) with cerebral palsy (CP) at the same time as other surgical procedures as appropriate. The transfer was either medial to the sartorius (62 sides), semitendinosus (19 sides), or the gracilis (14 sides) muscles, or laterally to the iliotibial band (10 sides). Gait analysis performed before and 1 year after operation demonstrated increased knee range of motion (ROM) with increased extension at initial contact and in midstance and maintained knee flexion in swing. There were no statistically significant differences between the four transfer sites in the effect on those variables. Therefore, the choice of rectus femoris transfer site can be dictated by surgical preference or by the nature of other simultaneous procedures. There was no consistent change in transverse plane motion of the hip or foot progression angles between the two gait analyses, suggesting that rectus femoris transfer does not affect gait abnormalities observed in the transverse plane.

Rectus femoris surgery in children with cerebral palsy. Part II: A comparison between the effect of transfer and release of the distal rectus femoris on knee motion.

Summary Rectus femoris muscle (RF) surgery was performed in 98 children (136 sides) with cerebral palsy (CP). RF transfer was performed in 105 lower limbs, and distal RF release was performed in 31. Eleven (20 sides) similarly affected children had no RF procedure and are included for comparison. Gait analysis was performed just before and ∼1 year after surgery. All children underwent other orthopaedic surgery at the time of the RF procedure. When preoperative knee range of motion (ROM) was >80% of normal, there were no significant changes in knee motion in either the RF transfer or distal release groups. In patients with <80% of normal knee ROM preoperatively, RF transfer was followed by maintained knee flexion in swing; patients who underwent distal RF release or no RF procedure showed a decrease (10° and 6°, respectively) in knee flexion postoperatively. These results suggest that the RF should be transferred and not released when knee ROM is <80%.

A comparative study of ambulation-abduction bracing and varus derotation osteotomy in the treatment of severe Legg-Calvé-Perthes disease in children over 6 years of age.

Summary: Thirty-six patients with severe Legg-Calve-Perthes disease were reviewed retrospectively to compare the results of ambulation-abduction bracing with varus derotation osteotomy. There were 17 brace patients and 19 osteotomy patients, and all were aged >6.9 years. Treatment results were equal. The percentage of acetabular coverage, extent of lateral femoral subluxation, and the age of the patient affected outcome. The varus neck-shaft angle and leg length discrepancy resulting from the osteotomy were not permanent. The articular trochanteric distance appeared to be affected more by the neck- shaft angle recovery than by epiphysiodesis of the greater trochanter.

The Clinical Use of Kinetics for Evaluation of Pathological Gait in Cerebral Palsy

Until very recently, gait problems in children who had cerebral palsy had been treated empirically, and this empiricism had been based only on observation of the child’s gait and the clinical evaluation. However, in the more recent past. there have been efforts to approach gait disorders in cerebral palsy on a more scientific level, by assessment of the child preoperatively and postoperatively with use of computerized gait analysis. Kinesiology, which is the study of gait, can be divided into two areas: kinematics and kinetics. Kinematics is the study of motion without regard to the forces that produce it. An example of this is the sagittal plane graph of knee motion (Fig. 1). Kinematics, therefore, gives a precise description of the motions that are occurring in a particular joint in all three planes during the gait cycle, hut the measurements are essentially descriptive and do not provide any insight into the cause of the motion. Kinetics, on the other hand, deals with the forces that produce the motion. These measurements includejoint moments andjoint powers. In 1987. Winter described the way in which kinetics are calculated (a procedure known as inverse dynamics) and discussed some of the possible clinical uses for kinetics9. Subsequently. Davis et al. and Ounpuu et al. developed clinical software that describes the moments and powers of each of the three major joints of the lower extremity in all three planes. Employment of these parameters for the assessment of normal and pathological gait led to the discovery that these measurements can provide a great deal of insight into the specific gait abnormalities associated with cerebral palsy. Before proceeding with the discussion of the clinical use of kinetics, it is necessary to have insight into how kinetic information is calculated. The process is known as inverse dynamics. In addition. to understand inverse dynamics. some concepts from basic physics must first

Adaptability of Motor Patterns in Pathological Gait

Human walking is a complex motor control task requiring the integration of central and peripheral control of scores of muscles acting on a skeletal system with many degrees of freedom. Associated with the goal of forward progression is the overriding need for a safe transit: balance control to prevent falling over, a support control to prevent collapse against gravity, and a fine motor control of the foot during swing to ensure a safe toe clearance and a gentle heel contact.