APPLICATION OF GAIT LABORATORY IN REHABILITATION MEDICINE

Simon F.T. Tang, MD., Carl P.C. Chen, MD., Max J.L. Chen, MD.

Higher quality photo images (and photo captions) can be viewed by clicking on the relevant photo thumbnail.

Department of Physical Medicine and Rehabilitation Chang Gung Memorial Hospital, Taipei, Taiwan

Figure 1: Our team members (from left to right): Mr. Wei-Hsien Hung, our gait laboratory's engineer; Dr. Simon F.T. Tang, the director of our physical medicine and rehabilitation department; Dr. Hsin-Chin Chen, the consultant of our gait laboratory in the field of biomechanics; our newly appointed attending physicians, Dr. Max J.L. Chen, and Dr. Carl P.C. Chen.

During the past decade, we have successfully applied our gait laboratory in the evaluation and analysis of treatment effects in many gait disorders. We have five physiatrists constantly involved in conducting research in the gait laboratory. Dr. Alice M.K. Wong, our hospital's vice superintendent, specialises in the field of pediatric rehabilitation medicine. She is concerned with the gait pattern of cerebral palsy children. Gait pattern improvement after such treatment as botulinum injection can be further confirmed by gait analysis in our gait laboratory. Dr. Simon F.T. Tang, the director of our physical medicine and rehabilitation department, is especially interested in the gait pattern changes before and after the fitting of prostheses or orthoses. Dr. Chia-Lin Chen, who also specialises in the field of neurologic and pediatric rehabilitation medicine, is particularly interested in the gait pattern of stroke patients. Dr. Carl P.C. Chen and Dr. Max J.L. Chen, the two newly appointed attending physicians in our department of physical medicine and rehabilitation, have conducted studies on pre-operative and post-operative gait patterns in orthopaedic patients. Our gait laboratory is presently supervised by a capable engineer, Mr. Wei-Hsien Hung.
Our gait laboratory features a Vicon 370 motion analysis system, and 3 AMTI forceplates. The Vicon 370 system includes six infrared cameras for kinematic data collection, and a computer for data analysis. Two of our forceplates are of Model OR6-5-1000, and 1 of Model OR6-5-2000. We have selected four of our studies for further discussion below:

1. The Improvement of Gait Patterns in Heel Defect Patients with Free Tissue Transfer by the Application of Heel Elevated Total Contact Insole.
(To be published in the American Journal of Physical Medicine and Rehabilitation)
In this study, elevated total contact insoles were applied to traumatic heel injury patients who underwent flap reconstructions. Gait pattern was analysed sensitively to determine the effectiveness of the insoles. In traumatic heel injury patients, the forefoot is frequently used for initial foot strike instead of the heel for the prevention of pain. We have designed a new total contact insole with slight heel elevation for these patients. Gait analysis after wearing the total contact insoles revealed a more neutral ankle position during initial foot contact. Severe plantar-flexion during initial foot contact was no longer observed. The kinetic and kinematic data collected before the patient wore the total contact insoles revealed increased external rotational moment at the hip of the affected side to compensate for the weak ankle power necessary for toe-off and forward propulsion. After the application of the total contact insoles, greater energy could be stored for the affected side during initial contact, and more power generated during toe off. The above-mentioned compensatory hip external rotation moment was no longer observed.

2. Gait Analysis for Subjects with Traumatic Partial Foot Amputation Fitted with Carbon Fibre Partial Foot Prosthesis
In this study, gait pattern was again analysed after the application of partial foot prosthesis. The design of this prosthesis consisted of a partial foot filler mounted on an insole with an installed carbon fibre plate (Figure 2). After the application of the prosthesis, the supporting base was restored to increase the stance phase on the affected side. In kinetic analysis, energy for propulsion could be stored for the affected foot since heel contact, and could assist in a more efficient push-off phase. The overall kinetic and kinematic measurements from our gait laboratory proved that the partial foot prosthesis with an installed carbon fibre plate could restore foot function as a rigid lever for propulsion and as a mobile structure for shock absorption.

Figure 2: The partial foot prosthesis with installed carbon fibre plate.

3. An Electromyographic Study of Vastus Medialis Obliquus and Vastus Lateralis Activity in Open and Closed Kinetic Chain Exercises in Patients with Patellofemoral Pain Syndrome.
(Accepted by the Archives of Physical Medicine and Rehabilitation and was published in the August edition of 2001)
Many rehabilitation strategies have been implemented for patients with patellofemoral pain syndrome (PFPS). In general, the goals of patellofemoral rehabilitation are to maximize vastus medialis obliquus (VMO) muscle strength while minimizing the patellofemoral joint reaction force and stress (PFJRF and PFJRS). Recent works indicated that the best method to strengthen the quadriceps group while incurring the least PFJRFs and PFJRS is via a short-arc (<45 degrees flexion to extension) closed kinetic chain exercise. However, with the combination of electromyography measurement, we discovered that the maximum VMO muscle strength was obtained during 60 degrees closed kinetic chain exercise. In order for the knee flexion-extension angle measurement to be precise, body markers were placed on the lower limbs to measure precise angles during stand-to-squat, and squat-to-stand manoeuvres (Figure 3). This is perhaps the most precise method in measuring knee flexion and extension angles. Therefore, we have arrived at a different conclusion, that maximal VMO muscle contraction can be achieved via closed kinetic chain exercise to 60 degrees of knee flexion, not 40 degrees.

Figure3: Precise knee angle range of motion can be calculated from the body markers.

4. Analysis of Cane-Assisted Gait in Patients with Hemiplegic Stroke.
(This work was accepted by the Archives of Physical Medicine and Rehabilitation and published in the January 2001 edition)
We have performed gait analysis for cane-assisted gait in patients with hemiplegic stroke, and a force sensor was placed over the tip of the cane. Therefore, the force exerted on the cane could be calculated. In this study, body markers were placed not only at the legs but also at the cane (Figure 4). The forceplates measured the shear forces and vertical forces from the legs and the cane. Interestingly, we discovered that hemiplegic stroke patients used the sound limb for propulsion, and the affected limb and cane for braking. It was originally believed that the major role of the cane in hemiplegic gait would be for purposes of support rather than braking. However, this study proved that the cane provided only less than 25% of body weight as a means of support, while its main function was for braking.

Figure 4: Kinetic and kinematic measurements through forceplates and body markers. Note the markers on the cane.

In summary, with the current achievements in technological advances, most gait laboratories can offer three-dimensional pictures for gait pattern and force analysis. In addition, motor control studies can be conducted with combined application of dynamic electromyography (EMG). There are many application opportunities in the fields of prosthetics and orthotics, orthopedics, and neurology and for evidence-based studies in rehabilitation medicine.

Simon F.T. Tang, MD.,
Associate Professor and Director,
Carl P.C. Chen, MD.,
Attending Physician,
Max J.L. Chen, MD.
Attending Physician,
Department of Physical Medicine and Rehabilitation
Chang Gung Memorial Hospital and Chang Gung University
Taipei, Taiwan