Restoring a patient’s ability to perform everyday activities only begins with the fitting of the prosthesis. For lower limb amputees, gait analysis and training are the necessary next steps to ensure restoration and maintain comfort and function.
Many lower limb amputees take on pathological gait patterns where certain movement deviations substitute for those that the amputee cannot perform. Jacquelin Perry, MD, said in her book Gait Analysis: Normal and Pathological Function, these compensations cause energy cost to increase and often compromise function.
Asking the right questions
“Is it a physical problem that needs to be corrected with physical therapy or is it a prosthetic problem that has to do with fit or alignment?” said Robert Gailey PhD, PT, associate professor at the University of Miami School of Medicine and health scientist researcher for the Miami Veterans Affairs Medical Center.
“If I can correct the alignment with my hands, then it is not a prosthetic problem. But if the person is walking correctly and we still see the gait deviation, it tends to be a prosthetic problem,” he said.
Figuring out what questions you want to answer is key in determining how to use gait analysis.
“Like anything in medicine, you have to select the right tool to satisfy the right question,” Gailey explained. “Just putting somebody on the gait analysis equipment does not often provide the answer you are looking for.”
But asking the right questions can be a complicated and overwhelming task due to the extent of combinations of technology and patient-specific factors that a clinician considers – so much so that a complete list cannot be compiled.
Gailey offered the following examples. If you wanted to investigate shear forces at the foot, then the use of force plates may be appropriate. If you want to determine the moments and how the moments are affecting the lower limb, forces and the joint angles would be examined. If simple temporal-spatial data such as step length or step width is required, pressure mats or pressure paper could be used. Furthermore, some systems measure pressure between the shoe and the floor. Other systems are worn inside the shoe to examine the pressure between the foot and the shoe.
It is because of these questions that computerized or instrumented gait analysis has been used as more of a research tool to draw broad generalizations about the amputee’s gait as opposed to clinically refining the amputee’s prosthetic alignment.
Each individual patient has a unique prosthetic fit depending on a number of factors including residual limb length, age and activity level. These factors, among others, cause patients to take on pathological gait patterns that cause excessive energy output as well as additional stress on the body.
While each individual patient has a distinctive gait, there are only so many ways to compensate for a loss. Some common gait compensations have been established, although there are slight differences in everyone. Dynamic Bracing Solutions has compiled a list of these compensations on their Web site citing the following for prosthetic and orthotic wearers:
- Truncal deviations. This balancing strategy shifts about 70% of the body weight horizontally.
- Excessive hip flexion. This strategy causes the person to lift 15% of their body weight against gravity and is usually seen to compensate for ankle contracture.
- Circumduction. This also calls for a 15% body weight shift. It is when a person swings the leg out to one side in order to clear the ground during advancement.
- Circumduction accompanied by trunk shifting. Much like the previous strategy, this is when a person shifts his or her trunk to the other side usually applied when hip muscles are weak.
- Hip hiking. This strategy is notable as the pelvis is lifted to one side to allow for the leg to clear the ground.
- Vaulting. This is when a person raises almost all of his or her body weight vertically against gravity in an effort to clear the ground.
A common concern that prosthetists and therapists aim to alleviate is excessive energy expenditure caused by employing compensations.
Eileen Fowler, PhD, PT, associate professor in the department of orthopedic surgery at UCLA and director of the Kameron Gait and Motion Laboratory told O&P Business News that the amount of energy required during walking can be quantified by collecting expired air and measuring the oxygen consumption. The higher the level of amputation, the greater the cost during walking. Many compensations, such as vaulting, result in excessive energy expenditure. Gait training can be an effective way of minimizing energy costly compensations.
The role of prosthetic training
Gait training might seem like the answer to a gait problem. However, Gailey explained that reeducating and preparing the body to walk with a prosthesis is crucial before an amputee’s ability to walk with a prosthesis can be appropriately evaluated.
“The majority of gait deviations that are observed initially are due to a lack of, or being in the process of, gait training,” Gailey said. “In my experience, prosthetic gait deviations are most often corrected through therapy than with a wrench. When the person has achieved optimal gait through training, then the prosthetist and physical therapist can come together to fine tune the prosthetic alignment.”
Gailey stressed the importance of teaching before analyzing. As a physical therapist, he assumes the responsibility of working with patients after they are fitted with a prosthesis and, during those first few weeks, he said it is necessary to ignore those minor gait deviations that are caused by the prostheses.
“I teach people how to use the prosthesis. I teach people how to reeducate their body to walk again,” Gailey said. “The most important time is when I, the therapist, and their prosthetist are in the same room at the same time and together we watch the patient walk. Then the prosthetist can make the appropriate adjustments.”
Gait analysis of children
Working with children brings a different set of challenges that change with age. He said that gait training has to be applied in the form of play for children under 10 years old. Children will comply for short periods of time during a therapy session and respond with a very nice gait pattern. However, appearance is rarely important to a child. As a result, when he or she wants to move quickly or are free to walk as they wish, they will revert to what is natural to them.
“During therapy, the minute you turn to talk to mom and a child sees a ball in the corner, he will run to get the ball in whatever pattern feels most comfortable to him,” Gailey said.
Children develop their own gait strategies
Gailey said children in this age group develop their own gait strategies to suit their needs. Whether to play, run or walk, they figure out what works best for them and continue this behavior.
Gailey also suggests annual check-ups to watch for postural deviations such as scoliosis and other muscular imbalances that would limit a child’s range of motion and ability to achieve their goals as they mature. If there are no clinically relevant postural issues, allowing a child up to about the age of 12 to use his or her own strategies to walk is fine, he added.
At about 12 years of age, the challenges change again. As children approach their teen years, they become increasingly aware of their self-image and how others perceive them. This is when gait training a child is best and easier because they are so aware of the world around them, and fitting into that world becomes a priority. To them, walking naturally is a necessary part of achieving that goal.
“Teens begin to realize that they are different because of the prosthesis and now they have a vested interest in how they walk,” Gailey said.
Good prosthetists and therapists work alongside a teen at this age and teach him or her to walk, while also eliminating the issues that the child’s own gait strategies may have created.
Fowler has worked with two different types of pediatric patients – children with congenital anomalies and children who have had traumatic amputations.
“A child who loses a limb is different than a child who grows up with a congenital deformity,” Fowler said. “I think that children born with a problem accept it more.”
Fowler also agrees with Gailey in that children around the age of 12 years old begin to compare themselves with others their age.
“Body image is a problem in general with teenagers so you have some more issues to deal with if you have a prosthesis,” Fowler said. “Teenagers are more interested in normalizing their gait compared to younger children.”
Challenges of gait analysis
The human body is constantly changing. Collecting data that holds true for extended or even shorter periods of time is challenging. A full gait analysis is a time consuming and sensitive process that cannot yield quick-fix answers.
From the moment you begin to examine a patient through computerized gait analysis, to the time an assessment is made, takes typically a week, Gailey said.
“During that week, the patient may have become stronger, the alignment may have changed, the socket may have changed, the socket fit may have changed so that by the time you come back to look at the patient, you may be looking at a different set of data,” Gailey said.
Additionally, the fact that each person has specific gait deviations unique to him or her complicates data gathering.
While working with children, Fowler finds that they often have standard prostheses that are relatively simple allowing for comparative case studies at the UCLA gait lab.
“When I have examined gait in adults, each one is a case study because their prostheses are so unique making research challenging,” Fowler said. “Adults often have expensive and complicated prostheses while most of the children that I have worked with have simple, standard prostheses.”
Using standardized testing methods
Gailey agrees that standardizing testing methods would help to conduct better research.
“We have to make sure that we are testing relatively the same level of amputee who has had the same training and fairly the same type of prosthetic componentry,” Gailey said. “Then we can look at differences between how the amputee is trained, and it is really rare that you have the funding and the patient population to conduct that type of research.”
The most widely used method of gait analysis, observation, further complicates outcomes due to the amount of subjectivity that exists.
“As much as we try to make it objective, we are still left with a subjective analysis of how a person ambulates. Primarily because much of the information gathered is still open to interpretation of the rehabilitation team,” Gailey said. “For now, the most efficient clinical tools that the prosthetists and physical therapists have today are still their own eyes and own experience.”
For more information:
- Perry J. Gait Analysis: Normal and Pathological Gait Function. Thorofare, NJ: SLACK Incorporated; 1992.
- Rose J, Gamble JG. Human Walking. 3rd ed. Philadelphia: Lippincott Williams & Wilkins; 2006.
Jennifer Hoydicz is a staff writer for O&P Business News.