James J. Carollo

A comparison of paraplegic gait performance using two types of reciprocating gait orthoses

This study examined the energy cost of ambulation using the reciprocating gait orthosis (RGO) and the modified Isocentric RGO in paraplegic spinal cord injured subjects. In 4 subjects, the rates of O2 consumption per minute, O2 cost per metre, heart rate (HR), respiratory exchange ratio, velocity, and physiologic cost index (PCI) were measured during ambulation with the two orthotic devices. PCI was calculated by dividing the difference between walking and resting HR by velocity. PCI was significantly lower during ambulation trials with the Isocentric RGO compared to the RGO, but was the only measurement that detected a significant difference beween the two orthotic devices. These results indicate that energy costs of ambulation at self-selected speeds were lower with the Isocentric RGO compared to the standard RGO. Furthermore, PCI could be used as a sensitive indicator of gait efficiency in spinal cord injury subjects.

Presenting joint kinematics of human locomotion using phase plane portraits and Poincaré maps

Additional graphical tools are needed to better visualize the joint kinematics of human locomotion. Standard plots in which the joint displacements are plotted against time or percent gait cycle do not provide sufficient information about the dynamics of the system. In this article, a study based on the two graphical tools of nonlinear dynamics to visualize the steady-state kinematics of human gait is presented. An experimental setup was developed to acquire the necessary data for application of the techniques. Twenty young adults, whose medical histories are free of gait pathology, were tested. Computerized electrogoniometers and foot switches were used to measure the kinematic data of the lower extremities and capture four instants of the gait cycle: heel strike, foot flat, heel off, and toe off. Phase plane portraits of each joint were constructed for the sagittal plane by plotting angular velocity against angular displacement. Poincaré maps were obtained by periodically sampling the joint profiles at toe off and plotting the ith iterate against the (i + 1)th one. Phase plane portraits are useful in monitoring the variations of joint velocity and position on the same graph in a more compact form. Poincaré maps are effective in differentiating steady gait from transient locomotion.

Effectiveness of instrumented gait analysis in children with cerebral palsy--comparison of outcomes.

Abstract: The aim of this study was to evaluate the impact of instrumented gait analysis on the walking performance of children with cerebral palsy at The Childrens Hospital, Denver. The study population consisted of 2 groups of 10 children; an experimental group (X) and a recommendation matched control group (C). All subjects had 2 instrumented gait analyses at least 1 year apart. Group X was composed of patients who abided by the gait analysis recommendations and completed all surgical interventions. Group C included patients who chose not to follow surgical recommendations from the initial gait analysis but instead pursued alternative nonsurgical treatments. Sagittal and coronal plane kinematic outcomes for each surgical procedure were obtained from comparing sequential instrumented gait analyses, and analyzed using logistic regression. Group X was found to experience a significantly higher percentage of positive outcomes (44%) than Group C (26%). The calculated odds ratio using the Wald test indicated that patients who complied with gait analysis surgical recommendations were 3.68 times more likely to experience a positive outcome than recommendation matched patients who chose not to follow gait analysis recommendations.

The Role of Gait Analysis in Treating Gait Abnormalities in Cerebral Palsy

Individuals with cerebral palsy (CP) cannot take a normal activity like walking for granted. CP is the most common pediatric neurologic disorder, with an incidence of 3.6 per 1000 live births. The current trend in the treatment of individuals with CP is to perform a thorough evaluation including a complete patient history from birth to present, a comprehensive physical examination, appropriate radiographs, consultation with other medical specialists, and analysis of gait.

Physiologic costs of reciprocal gait in FES assisted walking

This study reports the velocity and physiologic cost index (PCI) of ambulation using a functional electrical stimulation (FES) system for ambulation in paraplegic spinal cord injured subjects. Using established techniques, average velocity and heart rate (HR) were measured on five subjects trained with the Parastep® system. PCI was reported for the four subjects who achieved a steady state during ambulation with the Parastep® system. It was found that walking performance varied greatly between subjects, and was correlated to frequency of use of the system. Velocity of walking with the Parastep® system ranged from 4.6 to 24.3m/min. In the four subjects where steady state was achieved, PCI ranged from 2.30 to 6.26 beats/m. The average walking speed and PCI were similar to the values reported using alternative mechanical or hybrid systems available to the spinal cord injured for restoration of upright locomotion.

Sensitivity of spinal cord monitoring to intraoperative events.

Summary: Intraoperative somatosensory evoked potentials in 50 patients were reviewed; each waveform was correlated with intraoperative surgical events and conditions. Twenty-two patients maintained reproducible waveforms and awoke without neurological deficit. Two patients had random waveform changes not correlated with a surgical event and awoke without deficit. Twelve patients showed waveform changes temporally related to circumstances that might endanger cord function; two of these awoke with transient neurological abnormality. Satisfactory waveforms were not obtained from 14 patients. Somatosensory evoked potential monitoring in scoliosis surgery appears to be sensitive, but may not be sufficiently specific; waveform changes do not necessarily indicate objective neurological damage

Biomechanics of scoliosis correction by segmental spinal instrumentation.

The mechanical effectiveness of applying transverse forces by segmental spinal instrumentation to correct scoliosis is examined in this paper. Comparisons with traditional Harrington instrumentation are made on the basis of each methods potential to produce corrective bending moments and their ability to transfer this correction to the spine. Recognizing the scoliosis is a three-dimensional deformity, biomechanical evaluations are performed in each of the three anatomic planes, with special attention paid to maintaining normal sagittal plane contour and transverse plane derotation. Such an analysis indicates that segmental spinal instrumentation has a clear mechanical advantage over traditional Harrington instrumentation in providing and maintaining correction. Proposed improvements include the development of instrumentation which can be segmentally attached to the vertebra without invading the spinal canal.

Rectus femoris transfer in children with cerebral palsy: evaluation of transfer site and preoperative indicators.

Background: Rectus femoris transfer (RFT) is a treatment option for children with cerebral palsy (CP) who exhibit a stiff-knee gait pattern. The rectus femoris muscle is transferred to different sites to overcome problems such as tripping and falling. Indications for RFT often include preoperative decreased knee range of motion (KROM) during swing phase, reduced peak knee flexion in swing (PKFSW), abnormal rectus femoris firing patterns on electromyography recordings, and a positive Duncan-Ely test. This study investigated the effect of different RFT sites on kinematic outcome variables and evaluated the relationship between commonly used preoperative surgical indicators and postoperative changes in kinematics. Methods: Thirty-eight patients with CP, who underwent RFT, with preoperative and postoperative instrumented gait analyses, were evaluated and divided by transfer site: semitendinosus, sartorius, and gracilis. Preoperative and postoperative comparisons were made for 5 knee kinematic variables: range of motion (KROM), peak flexion at loading response, peak extension at terminal stance, PKFSW, and peak extension at terminal swing. Analysis was performed in accordance to different transfer sites and overall postoperative change. Results: When all limbs were analyzed together for the 5 outcome variables, it was found that patients experienced significant (P < 0.05) improvements in sagittal-plane kinematics in 3 of the outcome variables: KROM, PKFSW, and peak extension at terminal swing. Patients had a significant improvement in postoperative KROM when the preoperative KROM was less than 80% of normal. Electromyography pattern and Duncan-Ely test were not found to be useful indicators of surgical success. Conclusion: The authors recommend RFT in children with CP who exhibit a stiff-knee gait, regardless of transfer site. Level of Evidence: Level 3.

Are our expectations bigger than the results we achieve? a comparative study analysing potential advantages of ankle arthroplasty over arthrodesis.

PurposePrior studies have reported improved gait performance and kinematics after total ankle arthroplasty (TAR) compared to ankle arthrodesis (AAD). Given these findings, AAD has been primarily considered as a salvage procedure that may lead to adjacent joint degeneration.MethodsA total of 101 TAR and 40 screw arthrodeses were enrolled in a retrospective study with a prospectively designed follow-up examination that included gait analysis and outcome assessment with the AOFAS hindfoot score and FAOS questionnaire.ResultsSignificant asymmetry in gait and reduced range of motion compared to normal remained after both procedures. Subjective outcome improved after both procedures, and pain was significantly better after TAR. Limited functional gains after TAR and joint degeneration to the same degree after both procedures was seen in the mid-term. Hindfoot fusion seemed to have a greater impact on postoperative function than ankle arthrodesis.ConclusionConsidering only minor functional gains of TAR compared to AAD the implantation of current TAR designs in large patient series may be questioned.

The mechanics of thoracolumbar fractures stabilized by segmental fixation.

Patients with unstable thoracolumbar spine fractures greatly benefit from the rapid mobilization made possible by surgical reduction and secure internal fixation. The Harrington distraction method provides excellent hook fixation to the spine but is attached only to the proximal and distal ends of the instrumental segment and is dependent on an intact anterior longitudinal ligament. Because the spine is multisegmented and viscoelastic, a distraction method alone may not provide persistent tension on the anterior longitudinal ligament. Segmental spinal instrumentation (Luque) is less efficient in obtaining reduction because it has no built in distractive mechanism. In addition, the lack of laminar hook attachments is a significant disadvantage in maintaining a distractive force. A combined system consisting of Harrington distraction rods segmentally attached to all available motion segments improves the currently available mechanical construct for obtaining and maintaining reduction in unstable thoracolumbar fractures.