Abstract
Welcome to this special issue of Prosthetics and Orthotics International on lower limb orthotics. While the topic of lower limb orthotics is vast and challenging, this special issue focuses predominantly on the use of ankle foot orthoses for persons with neurological impairments. Whereas each article provides interesting insights into particular aspects of orthotic intervention, together the articles highlight a number of broader, ongoing issues with regards to the execution and communication of orthotic research.
According to ISO #8549-1 (1989) orthotics is “the science and art involved in treating patients by the use of an orthosis” i.e., “an externally applied device used to modify the structural or functional characteristics of the neuro-musculoskeletal system.” Orthotic treatment may encompass numerous clinical objectives such as relieving pain and/or managing deformities and abnormal neuromuscular function. To accomplish these objectives five functional requirements have been identified: (1) prevent, reduce, or stabilize a deformity; (2) modify the range of motion of a joint; (3) add to the length or alter the shape of a segment; (4) compensate for weak muscle activity or control muscle hyperactivity; and (5) reduce or redistribute the load on tissues (ISO #8549-1, 1989). These requirements are predicated on the mechanics of the device as well as the interaction of the device with the individual user. In his article, Haarlar et al. argues that the mechanical specifications of the device must be evaluated alongside functional evaluations with human subjects if we are to gain a more precise understanding of the efficacy of various orthotic interventions. 1 Additionally, the article in this issue of Prosthetics and Orthotics International by Bregman et al. 2 illustrates the insights that might be gained from a combined approach to orthotic research wherein the mechanical performance of devices are assessed alongside functional evaluations with human subjects. This approach may also serve to alleviate criticisms that too often the orthosis is insufficiently described in published research 3
Based on study designs, the articles presented in this issue represent low to moderate levels of evidence for lower limb orthoses. Perhaps the exception in this issue is the article by Bowers and Ross 4 which is based on a systematic review and may therefore be considered Level I evidence 5 . While it is not always feasible or practical to conduct randomized controlled trials (which are considered to provide the highest level of evidence because of the study designs ability to limit the influence of potential biases), it is also not always necessary. The decision as to the best study design should be based on the research question. The cross-over design used by Mulroy et al. 6 and Forghany et al. 7 is often an appropriate one with regards to many orthotic research questions and, when well executed, can be a strong study design for application within orthotics research. Cross-over studies, especially when the order of presentation of interventions is randomized as in the Forghany et al. study 7 , gain their strength from the repeated measures approach, which allows subjects to act as their own controls. This approach tends to require relatively fewer research subjects and potentially a less heterogenous population in order to assess a particular research question.
Heterogeneity within the population of orthosis users and within orthosis designs themselves is also a challenge to orthotic research. When designing a study, researchers must determine to what extent they will standardize the orthotic intervention being studied and how that will influence their subject inclusion criteria. Clinically, custom orthoses are individualized to the particular persons needs based on the clinical judgment of the orthotist. However, using this approach in research can lead to the introduction of confounding variables such that the influence of orthotic design on function cannot be ascertained. On the other hand, standardization of the orthotic design within a study may limit the patient population suitable for the study, resulting in tighter inclusion criteria and greater difficulties with subject recruitment.
A conundrum exists in that single subject research and case studies such as those by Jagadamma et al. 8 and Pittaccio et al. 9 are perhaps most readily understood by practitioners and therefore the information more readily transferred to clinical practice. Although easier transference of knowledge may occur when case studies mirror clinical encounters, generalizability of results from one case to an entire population cannot be achieved and so these contributions to knowledge are positioned lower in the hierarchy of evidence.
The above are examples of the challenges faced by researchers when designing and executing lower limb orthotic research, but there are also challenges to the communication of research findings that are shared by both researchers and clinicians because they affect the implementation of research findings into patient care. The model of Evidence Based Practice is predicated on the concept that knowledge translation occurs between researchers and clinicians. Knowledge translation has been defined as “the exchange, synthesis and ethically-sound application of knowledge - within a complex system of interactions among researchers and users.” (Canadian Institutes of Health Research http://www.cihr-irsc.gc.ca/e/29418.html). The goal of knowledge translation is to accelerate the implementation of research findings to the benefit of those requiring clinical services.
There has been much discussion in the literature regarding barriers to knowledge translation. One example of the challenge practitioners face in remaining cognizant of current prosthetics and orthotics research findings is that they are widely dispersed across many different publications. This special issue of Prosthetics and Orthotics International includes three reviews that facilitate knowledge translation by summarizing for the prosthetics and orthotics field relevant information that has been published elsewhere: Bowers and Ross 4 report on a Best Practice Statement for the use of ankle foot orthoses after stroke recently published by the NHS in Scotland, Morris et al. 10 provides an overview of three publications describing the development of a new outcome measure for children with ankle-foot problems, and Owen 11 reviews the evidence base for development of an orthotic approach for management of children with neurological impairments such as Cerebral Palsy.
It is my hope that this special issue will contribute to the facilitation of knowledge transfer from research to the clinic through its focus on lower limb orthoses and through the inclusion of review articles. No one study can definitively answer any question for there is no such thing as a perfect study that provides 100% certainty as to the results. It is through synthesis and duplication of results that we gain confidence in particular findings. Given the scope of these challenges, a successful research enterprise requires the contribution of every member of the profession at every level.