The successful orthotic management of abnormal or pathologic gait is a demanding process that requires the orthotist to consider a seemingly endless number of factors. Crucial to this process is the ability to assess pathologic gait, which requires orthotists to have an in-depth understanding of normal locomotion and gait.
Understanding normal gait
The most fundamental part of identifying pathologic gait is understanding normal human locomotion because without a firm understanding of normal, the practitioner cannot identify abnormal gait, explained Bob Lin, CPO, FAAOP, chief orthotist for Hanger Prosthetics & Orthotics at Connecticut Children’s Medical Center.
“It is not just looking and saying, ‘Well, it looks like this person is limping,’ and that type of thing, but understanding the depth of really knowing the kinetics and kinematics of normal gait,” Lin said. “In the past, it was much more fill the prescription, but one of our domains in our practice as an orthotist is to actually assess pathologic gait as it directly relates to formulation of an orthotic treatment plan.”
Changes in the educational standards for O&P practitioners in recent years have placed greater emphasis on courses such as clinical biomechanics, kinesiology, gait and pathomechanics, which has resulted in a foundational education that gives practitioners the skill set and tools to assess gait in the clinical environment, according to Lin, who also is the program director at the Newington Certificate Program in Orthotics and Prosthetics. He noted that an integral part of the program’s curriculum is the study of normal human locomotion and pathologic gait as it relates to varying differential diagnoses.
“Today’s orthotist-prosthetist coming out of the practitioner programs I would submit to you actually has as good if not better understanding, of normal and parhologic gait than a physical therapist does, which is quite a statement, but it is, in fact, quite true for graduates from most of the O&P programs,” Lin said.
To assess gait, practitioners typically use the prerequisites for normal gait originally postulated by Jacquelin Perry, MD. These prerequisites have become standard and are repeated throughout the literature on gait and locomotion, as well as being taught in most schools, Lin said. By looking at the requirements for normal gait, it becomes easy to extrapolate some of the common types of pathologic gait.
The following are the fundamental prerequisites for normal gait:
- Stability in stance
- Clearance in swing phase
- Swing phase pre-positioning
- Adequate step length
- Energy conservation.
In the first prerequisite of normal gait, stability in stance, the individual needs to be stable when the extremity is weight bearing and on the ground. During the second prerequisite, clearance in swing phase, as an individual advances a leg, the leg actually leaves the ground.
In the third prerequisite, swing phase prepositioning, as the heel is ready to come down and land, the foot needs to be in alignment and ready to accept the force as the individual takes a step. Lin refers to the analogy of a plane ready to land with the nose up and the wings level.
“You do not want the nose down and you do not want one wing really tilted in – you are not going to survive that landing,” Lin said. “In the same sense, your foot has got to be prepared to take the force.”
The fourth prerequisite, adequate step length, postulates that steps must be reasonable in terms of length, otherwise the gait is inefficient. The final prerequisite, energy conservation, dictates gait cannot take so much energy to ambulate that it is not a functional means of getting around.
“You have to have a baseline. To understand what is abnormal, you need to understand what is normal, and I also think there is an experiential component that is related to how effective we are able to see things,” Tom DiBello, BS, CO, FAAOP, president of Dynamic Orthotics and Prosthetics said. “Years ago, Perry described a methodology that she called observational gait analysis, and that is what most people in this industry use.”
Using Perry’s prerequisites of normal gait and observational gait analysis, the practitioner assesses and evaluates for abnormal gait. Patients are observed from the front, side and back for any types of gait deviations.
“An example would be is there some type of a Trendelenburg gait where the patient leans to the side,” Lin said. “Do they spend too much time in stance phase with the one extremity versus the other? Are they up on their toes? Are they spending too much time on their heels? There is really a whole host of complex things and the very subtle changes that may affect not only efficiency but stability and safety as patients walk.”
Lin also noted that the assessment and diagnostic component in determining what is abnormal can take as much if not more time than deciding on the material and design of the orthosis and casting the patient.
Identifying pathologic gait
Because pathologic gait represents all of the things that fall outside of normal human locomotion, it includes a wide variety of diagnoses, ranging from pes planus to something more involved such as paraplegia, explained Andrew Steele, CPO, a partner at Clark & Associates Prosthetics and Orthotics.
“Usually, patients have been seen by a doctor or a physical therapist, and the pathologic gait has already been identified, so when the patient walks in the door, we are aware that something is going on,” Steele said. “We see a wide variety of pathologic gait, anything from a simple foot drop in an adult due to cerebrovascular accident to a child with cerebral palsy. We work very closely with a rehab hospital here, so I would say that the bulk of the things we see are related to stroke or spinal cord injury.”
Regardless of the diagnosis or the actual gait deviation, it is important for every patient to be evaluated carefully as an individual. Gait characteristics should be assessed carefully, and the design of the orthosis should take into account the characteristics of each patient’s presentation.
“The problem so oftentimes is that individuals will use a cookbook approach to the management of patients based on their diagnosis,” DiBello said. “That is a bad way to practice, and it is important that we not attempt to categorize gait by diagnosis. You have to be really careful to effectively and appropriately evaluate each patient individually, and each orthosis needs to be designed to accommodate the particular needs of that patient in order to really optimize outcomes.”
Perry’s prerequisites of normal gait can be used to identify abnormalities during the different phases of gait. For example, in the first requirement, stability in stance, patients with a weak or paralyzed quadriceps muscle in the extensor will have an unstable knee. As the patient shifts onto that leg for support, the knee buckles. This type of gait abnormality can be observed in a polio patient or a patient with stroke, or someone who has a weak quadriceps muscle. Similarly, in patients who have a paralytic muscular disorder, during Perry’s second prerequisite of gait, which is swing phase clearance, their foot does not clear during swing phase because the foot is paralyzed.
“You could go over the entire myriad of diagnoses and say, ‘Well, this affects this prerequisite of gait or that prerequisite of gait,’” Lin said. “What are the more common types? There are paralytic disorders; there are alignment disorders. There is loss of motor function, poor alignment, or loss of stability, which is a combination of the two, or it could be sensory, so it is a balance disorder.”
Choosing the orthotic intervention
The patient’s type of deviation, primary functional deficit, and pathology determine the type of orthotic intervention. The primary goals of orthotic intervention are to create stability while allowing functional mobility that does not require too much energy.
“My goal with an orthosis is to control what I want need to control but still give the patient as much freedom as possible with the brace,” Steele said. “We can lock somebody up and control all kinds of things, but if they cannot be active in their everyday life and do the things they need to do, it really does not do much good.”
Steele also noted that successful bracing requires give and take.
“Sometimes you can accomplish 100% of what you want to accomplish. Sometimes you only get 75%, but if you have to give up 25% to allow patients to do more and be more active, then that is what you have to do.”
Ankle foot orthoses for pathologic gait can range anywhere from an SMO used mainly for mediolateral instability, to a solid ankle to restrict ankle motion and some knee motion, to different articulations at the ankle for restricting or assisting either plantarflexion or dorsiflexion, said Dean Sturch, CO, a partner at Clark & Associates Prosthetics and Orthotics.
“We have some new orthoses that we can use that let us do a combination of different things, so we can restrict motion to see if it is going to work. If it does not, then we can back up and give them different amounts of motion,” Sturch said. “With advances in the orthotic and prosthetic field, everything is not just a solid ankle any more; there is a lot more diversity in the orthoses to help us fine-tune and restrict as little but control as much as necessary.”
For pediatric patients, practitioners also must consider the stresses that the orthotic device may place on the child’s joints. Often, there is a tradeoff between function and protecting and stabilizing the articular surfaces of the joints.
“There has been a tendency over the years to focus on function primarily to the detriment of joint health,” DiBello said. “I think that as we see more and more children with physical disabilities becoming functional members of society, we are seeing more adults with disabilities who have painful knees, hips, ankles and feet. If they had been more appropriately managed as children, I think that they would be less painful as adults.”
At the initial fitting, patients usually are given a detailed wearing schedule for a “breaking in” period. In addition, patients are instructed in watching for potential skin breakdown problems. Steele noted that otherwise, there may of may not be a lot of routine follow-up visits.
“We let patients work with the brace and follow-up with us as needed if they are having problems,” Steele said. “There are times when you may have to try a couple of things before you get the right combination of components in the brace. You would like to think you can hit everything right the first time all of the time, but that is not always the case.”
Patients who may require close monitoring are scheduled for a 1-week or 2-week office visit to ensure there are no problems. Such patients include those identified as being at risk for skin breakdown or potential problems, or those patients who do not have a support system. However, Sturch noted that most patients continue to undergo physical therapy and are monitored closely by their therapists.
“If there is a problem, then we are contacted, and they are seen at clinic with the therapist or they make an appointment back to see us,” Sturch said. “There is a follow-up system that we have developed through years of working with the outside agencies.”
Lin described the fit of the orthosis as being the easy part of orthotic practice, noting that fit usually is not an issue, especially for practitioners with experience. In those cases, the orthosis “always fits.”
“The difficult part is that we have prognosticated a certain biomechanical impact of this brace on this pathology and this patient’s potential to ambulate. How close were we to being accurate?” Lin said. “I cannot tell with 100% certainty, I will never be able to, and I have been practicing 28 years now. It is still a little bit of a mystery, and that is what makes it interesting. Therein really lies the challenge of the high-level orthotic management.”
Mary L. Jerrell, ELS, is a correspondent for O&P Business News.
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