Nerrolyn Elissa Ford
Supervisors:
Dr. T. M. Bach, National Centre for Prosthetics and Orthotics, and
P. Bate, School of Physiotherapy, La Trobe University
A questionnaire study was conducted in order to identify potential sources of unreliability in observational gait analysis. Clinician responses indicated that the methods of visual search and the relative importance placed on gait variables differed between individuals. In an attempt to standardise the gait analysis process and eliminate errors caused by individual differences an observational gait analysis form was developed. The purpose of the form was to encourage participants to limit the amount of information collected during visual observation and to introduce a structured and systematic method of assessment.
A videotape reliability study was performed involving eight prosthetic clinicians. Prosthetists were tested for within and between rater reliability in detecting coronal and sagittal plane alignment deviations made to the prostheses of three male amputees. Four clinicians in test group 1 utilised the purpose designed gait analysis form during assessment. Test group 2, consisting of the remaining four clinicians, did not complete the gait analysis form.
The observational gait analysis form was demonstrated to have a significant effect on between rater reliability, with test group 1 out performing test group 2. Test group 1 achieved "almost perfect" agreement when assessing alignment shifts made in the mediolateral plane however agreement over anteroposterior alignment shifts was only "slight".
THE EFFECTS OF HARNESS SUPPORTED WALKING ON ABLE-BODIED SUBJECTS AND LOWER LIMB AMPUTEES
Timothy James Jarrott
Supervisors:
Dr. T. M. Bach, National Centre for Prosthetics and Orthotics, La Trobe University, and
B. Contoyannis, Rehab Tech, Monash University
Parallel bars have traditionally been used as a clinical tool during lower limb amputee rehabilitation. However, their use is associated with a number of disadvantages. An alternative may be an overhead harness system that relieves a portion of body weight during gait rehabilitation. Such devices have been demonstrated to be advantageous in the rehabilitation of neurological patients and other patient groups.
Three groups of nine subjects (young and elderly able-bodied and lower limb amputees) participated in the investigation to determine the effects of the overhead harness system on gait patterns. After a period of familiarisation, subjects were randomly tested during free-walking and 0%, 10% and 20% body weight support (BWS). Temporospatial data were recorded using a footswitch stride analyser and ground reaction force (GRF) data were recorded using a Kistler force platform. Subjective data were also recorded.
The results of this investigation revealed that as the level of BWS increased, both AB and LLA walking velocity decreased. Associated with the decrease in velocity were a decrease in stride length and cadence and an increase in gait cycle duration. As BWS increased, stance symmetry in the AB subjects remained unchanged while stance symmetry of the amputees decreased. Reductions in the vertical and anteroposterior GRFs were observed. Loading symmetry of the AB subjects remained unchanged while loading symmetry of the amputees increased. Subjectively, psychological benefits were reported.
The overhead harness system allows the user to ambulate along the walkway while reducing the peak forces applied to the lower limbs and providing safety and security. This may be important during early amputee gait rehabilitation. However, there are both negative and positive effects associated with the use of the system and its use as an alternative to parallel bars must be viewed cautiously.
QUADRICEPS ATROPHY IN TRANSTIBIAL AMPUTEES: RELATIONSHIP TO MUSCLE ACTIVATION PATTERNS IN NORMAL ACTIVITIES
Caroline O'Keefe
Supervisors:
Dr. T. M. Bach, National Centre for Prosthetics and Orthotics, Latrobe University, and
Prof. I. Brown, Department of Biomedical Engineering, Monash University
Atrophy of amputated limb thigh musculature is commonly observed in the transtibial amputee. The purpose of this investigation was to determine the relationship between this observed atrophy and muscle activation patterns which occur during common daily activities. The tasks investigated were level walking, stair ascent, stair descent, rising and sitting. Ten active unilateral amputee (TTA) subjects and ten able-bodied (AB) subjects participated in the study. Surface electrodes were used to record EMG activity of the quadriceps and hamstrings muscles as the subject completed the set tasks. The peak amplitude EMG was analysed and compared between limbs for each activity.
The AB subjects displayed symmetry of muscle activation in all activities. In level walking, the TTA subjects also demonstrated similar peak quadriceps activation between amputated and sound limbs. Postural compensations and altered thigh muscle activity were observed in stair ambulation. Although variations occurred,, the peak muscle activation in the amputated limb was not significantly different to the sound limb.
During the activities of rising and sitting, the peak activation in the amputated limb quadriceps was substantially reduced in comparison to the sound limb (p<0.001). This result may be due to the decreased lever arm of the tibial remnant or to limitations of the prosthetic socket. The inability to flex the knee past ninety degrees, or pain at the anterodistal tibia due to pressure on the socket will result in the transfer of most body weight to the sound limb during rising. The activities of rising and sitting are involved in the maintenance of normal strength in the AB individual. The sound limb dominance displayed by the TTA during these activities results in a reduced level of activation of the amputated limb quadriceps. A lack of sufficient muscle stimulation leads to disuse atrophy of the affected limb muscles. Although gait is an important functional requirement for the transtibial amputee, it is vital that other common activities are considered during prosthesis design and manufacture.
CONTINUING PROFESSIONAL EDUCATION FOR AUSTRALIAN PROSTHETISTS AND ORTHOTISTS
Bruce Douglas Poole
Supervisor: D. Radford, National Centre for Prosthetics and Orthotics, La Trobe University
Many professions and professional organisations encourage or demand that their members participate in continuing professional education (CPE). Professions that conduct continuing education programs maintain that the profession's status and standards are being safeguarded and/or improved. The act of participation in continuing education programs is seen as an important part of the development of a member of a profession. In health professions it has been inferred that participating in such activities leads to improved practitioner competence and prevents the practitioner's skills and knowledge from becoming obsolete.
A review of the literature was conducted to identify those areas relevant to the Australian Prosthetics and Orthotics profession and the perceived need to develop a continuing professional education program.
Information gained from the literature review highlighted the need to obtain more data from the Australian Prosthetics and Orthotics profession to ensure that future proposals are relevant and appropriate to the profession. The required data was sourced from the population of prosthetists and orthotists in Australia by the use of a mail out questionnaire. The questionnaire was sent to the entire estimated population of working prosthetists and orthotists in Australia (280 people). The response rate was 56.5%. Thus, as a representative sample, the survey achieved a level of confidence greater than 95% and has a margin of error of less than ± 3 %.
Results from the survey demonstrate that the profession is predominantly male (74.8%), although there is an increasing number of females entering the profession. Most respondents are employed full time (93.5%). Most work in positions that are funded by state resources (50%). The majority of the respondent population are employed as orthotists (53.6%), approximately one quarter work as prosthetists (23.4%) and 16.9% of practitioners work in a mixture of both prosthetics and orthotics. Seventy five percent of the respondents are members of the Australian Orthotic Prosthetic Association and 60% of the survey population have a tertiary level qualification in Prosthetics and Orthotics. The majority of respondents are presently engaged in some form of continuing education (84.5%). Ninety four per cent of respondents indicated that they would be willing participate in a structured continuing professional education program. Approximately two thirds of the respondents (67.1%) preferred the concept of a voluntary continuing education program. The preferred formats for programs were workshops and conferences but interest in distance education methods was also indicated. Respondents indicated that the Australian Orthotic Prosthetic Association and La Trobe University are the most suitable parties to be involved in conducting a continuing education program. The majority of respondents wanted a level of award or accreditation for participating in a continuing education program. The Australian Orthotic Prosthetic Association and La Trobe University were indicated as being the most preferred to provide relevant awards.
The collated data was used as the basis for the discussion of some of the relevant issues highlighted in the literature reviews. The main areas of discussion are: aims and objectives for a continuing professional education program, management of a continuing professional education program, program content, program formats, provision of funding, program frequency and the issue of compulsory versus voluntary participation.
The aim of this study is to present the issues and the corresponding relevant information in such a way that those reading this paper may be better informed and more able to make decisions regarding the development and implementation of a continuing professional education program for Australian prosthetists and orthotists.
THE EFFECT OF PROSTHETIC ALIGNMENT ON GAIT SYMMETRY AND ENERGY EXPENDITURE IN TRANSTIBIAL AMPUTEES Paul Harrison Retschko
Supervisors:
T. M. Bach, National Centre for Prosthetics and Orthotics, and
D. Orr, School of Human Biosciences, La Trobe University
The purpose of this study was to examine the effects of altering prosthetic alignment of transtibial prostheses on gait symmetry and energy expenditure. Despite the amount of discussion in the published literature, no previous investigations have attempted to quantify the relationship between prosthetic alignment, gait symmetry and energy expenditure.
Three transtibial amputees were recruited and fitted with an experimental prosthesis which permitted sagittal prosthetic alignment changes without interfering with settings in other planes. A clinical "optimum" alignment was achieved by a panel of prosthetists and from this, 10 mm and 20 mm anterior and posterior displacements of the foot beneath the socket were examined.
Kinematic, temporospatial and metabolic data were collected while subjects ambulated on a motor driven treadmill at a predetermined comfortable walking speed. From the kinematic and temporospatial data, an interlimb asymmetry ratio was calculated by dividing prosthetic side values by anatomical side data. The obtained ratios for the five tested alignments were compared to patterns in mean oxygen consumption rate and to other asymmetry ratios.
From analysis of results it was apparent that each subject responded differently to the alignment changes. This was evident in stance and swing durations, double support phase durations, knee and hip kinematics and in oxygen consumption values. Some symmetry ratios improved beyond the results for optimum alignment but these changes were not always consistent across subjects or with biomechanical theory. For example, for stance symmetry, one subject's VO2 decreased with increased symmetry, another subject displayed increased VO2 with increased stance symmetry and the remaining subject displayed no change in stance symmetry across alignments.
No one symmetry variable was consistently related to metabolic cost of walking across the subjects tested. On the basis of these results, we must question the clinical axiom that gait symmetry and energy expenditure are related.