A Closer Look At Case Studies In Gait Analysis

Author(s): 
David Levine, DPM, CPed

   When assessing patients, obtaining information via video and computer-assisted gait analysis may assist clinicians in more ways than they even realize. It is information that one may not otherwise obtain during a typical podiatric biomechanical examination. Watching patients ambulate can be very helpful in picking up key details that can inform the diagnosis and subsequent treatment plan.    One needs to consider other contributing factors as well. These factors include the patient’s occupation as well as the shoes he or she typically wears. For example, a woman wearing dress shoes and a man with steel toe work boots may have different complaints but both are likely related to how their shoes affect their feet. Therefore, it is important to look at the entire person both from a static and dynamic point of view.    Certainly, typical podiatric biomechanical intervention can address many problems that people encounter on a daily basis. However, there are many situations that present to us on a daily basis that need more detailed attention. Additional attention means understanding the way patients function. Simply having two feet does not mean that symmetry is something patients should take for granted. It is often asymmetry that causes the underlying presenting complaints.    For example, consider a patient who presents with plantar fasciitis one year, tendonitis another year and hallux limitus at another time. There must be other biomechanical forces that are causing these repeated injuries. Overuse may be one factor but overuse in combination with biomechanical asymmetry is even more important to assess.

Pertinent Pointers On Ensuring An Effective Gait Analysis

   Gait analysis can take on many forms. During podiatry school, we learned how to perform biomechanical exams. These exams often include watching a person walk up and down the hallway. However, subtle movements can occur in each foot and these are difficult, if not impossible, to pick up at normal speed with just your eyes. Subtle differences can also occur between feet that one may not see when the patient is walking in the hallway.    In addition, patients are often ill prepared for a proper gait analysis at the typical podiatric visit. When they try to bunch up their pants around the knees with the pants frequently falling to the ankles, it obscures the view of what we need to see. When you combine this with a waiting room full of patients, these biomechanical exams may be more rushed than you intended.    Indeed, it is important to schedule a time and place to perform a thorough analysis of their gait. One way to do this is by using a gait lab. A room with dimensions of approximately 15 feet wide and 30 feet long is sufficient to watch a person walk with the aid of video cameras located in different positions around the patient walking area. The patient should come prepared for this visit by bringing shorts, a T-shirt, typical shoes and orthotic devices if he or she already wears them.    Scheduling an appropriate amount of time for this exam is important. Even more advantageous is having an assistant or a technician run this test. That way, you will not be forced into making on the spot determinations of what you see. This permits the luxury of taking time to analyze the patient’s gait at your own pace and schedule. This is analogous to a patient undergoing a MRI or any other diagnostic test. Even thought the test is complete, it is expected that you will need time to read it. The same is true for gait analysis.    If you are forced to do the exam yourself, you will undoubtedly be peppered with questions about you are seeing. This will not be advantageous. This may force clinicians into making decisions or seeing things that they might not see otherwise. Performing a biomechanical assessment and a gait analysis will provide plenty of information to inform your base observations and diagnosis. When the patient returns for the follow up visit, the clinician is prepared to discuss these observations and offer recommendations.

What You Can Learn From Video Analysis And Pressure Mapping

   There are two parts to consider in this type of gait analysis. The first part is video analysis, which allows viewing the person from head to toe. Incorporating video from different angles is extremely helpful. One camera can allow you to view the patient both from the front and back but it is even better to have cameras at different heights in order to see and focus on different parts of the body.    One of these cameras can focus just on the feet. This enables you to see the leg, ankle and forefoot as the patient approaches, and then view the posterior aspect of the leg, ankle and heel as the person walks away. It is also helpful to have a camera from the side view in order to see sagittal plane motion in the hip, knee, ankle and first metatarsophalangeal joint (MTPJ) that occurs with each step. This camera can be on a tripod and actually track the person from the side view. Technology has greatly improved the ability to capture video. Digital video is affordable and easy to use. This form of video allows one to view it on the computer frame by frame. One can easily save this video on a DVD or CD-ROM. Accordingly, the video is easy to copy and edit if you are trying to make a report or summarize the findings.    Pressure mapping software will tell you what the foot is doing while it is on the floor. One can ascertain pressure distribution along with the direction and amount of forces. This is important in comparing feet from a quantitative perspective. We can make observations but when there are actual measurements and numbers to review, the findings will have more meaning.    With some patients, video may give more of the necessary information whereas pressure mapping may be more important in evaluating other patients. For instance, in a patient with diabetes mellitus and peripheral neuropathy, the pressure mapping software may provide more helpful information than video. On the other hand, when it comes to patients with asymmetry or subtle unusual mechanics, video may give you the best view. However, it is always helpful to have both. Sometimes, it is surprising which medium gives you the most pertinent information.    Approaching gait analysis in this fashion will enable clinicians to provide better biomechanical treatment in a more organized fashion. It is not as though every patient who presents to the office needs to undergo this type of examination. However, when the need arises, it is an excellent tool to obtain more information.    I have picked a few cases that illustrate how one can enhance their diagnostic efforts by incorporating gait analysis. One of the cases highlights a situation in which a patient had peripheral neuropathy and a chronic hallux ulcer. In the second case study, the patient also has diabetes mellitus, peripheral neuropathy and a chronic ulcer. This patient had undergone multiple surgeries but the ulcer persisted. In the third situation, a distance runner presented with chronic plantar fasciitis. He was already wearing orthotic devices but could not seem to get the problem to resolve. He also had periodic complaints of left knee and hip pain.

Case Study One: When A Patient Presents With A Chronic Hallux Ulcer

   A 55-year-old male presented with an ulceration on the plantar medial aspect of the left hallux. This ulcer had been present for several months and showed no signs of healing despite regular debridement. His history included a Jones fracture in the same foot five years ago. Two years ago, he developed an ulcer at the distal aspect of the second toe on this same foot. Subsequently an arthroplasty of the second toe allowed the ulcer to heal.    However, the patient developed a new hallux ulcer. He currently wears properly fitting, extra-depth footwear. He had previously used orthotic devices 10 years ago for plantar fasciitis. When the condition resolved, the patient stopped using the orthotics.    The patient also has a leg length discrepancy. He had used a 1/8-inch heel lift. Early on in the treatment of the hallux ulcer, orthotic devices were prescribed and fabricated. A 1/4-inch external shoe lift was also recommended. The thinking was that excessive pronation off the hallux during propulsion was the cause of the ulcer. However, after the patient used the orthotic devices, the ulcer actually enlarged. Since the ulcer was chronic and treatment was not helping, video/computer gait analysis was recommended.    I performed gait analysis in a few different situations. I began with video assessment of barefoot walking and followed up by obtaining video of the patient in shoes without the heel lift and in shoes with the heel lift. I subsequently utilized pressure mapping software to assess the patient’s gait in shoes with and without orthotic devices, and in shoes with and without the heel lift.    These gait analysis techniques revealed surprising information. The orthotic devices were actually contributing to greater pressure on the ulcer. While the goal of using the orthotics was to prevent the excessive pronation, there was actually more pressure on the hallux during propulsion. This additional friction and pressure contributed to chronic ulceration. In comparing shoes with the lift to shoes without, it was clearly evident there was less pressure on the hallux with the external shoe lift. Pressure mapping revealed that the optimal situation was having the lift on the shoe along with the regular insert that came with the shoe.    Video assessment revealed significant differences between the patient’s right and left sides both with and without the lift. Adding an external shoe lift was a necessity in this case in order to provide more symmetry and more equal pressures between his feet. The results showed that accommodative pressure relief around the hallux was the best situation along with the lift on the shoe.    In addition, periodic debridement was necessary to keep the callus to a minimum. Reducing pressures reduces the callus and a tendency for ulceration. In this particular situation, performing video and computer gait analysis provided a plan of treatment based on quantitative measurements. With confidence, I would administer this plan of treatment. If any changes occur, one can perform repeat gait analysis.

Case Study Two: When Multiple Orthotic Accommodations Fail

   A 62-year-old male presented with a chronic ulcer on the plantar aspect of the right foot. This patient had previously undergone a pancreas/liver transplant because of the effects of chronic diabetes mellitus. Over the years of having diabetes mellitus, he has developed profound peripheral neuropathy that not only affects his sensation but his motor function as well. As a result, he wears single, upright metal AFOs on both lower extremities. In addition, he has previously undergone a complete fifth metatarsal resection of the right foot, a fourth metatarsal osteotomy and second metatarsal head resection because of repeated ulcerations.    In addition to coming in regularly for podiatric care, the patient received recommendations along the way concerning footwear and accommodative orthotic devices. I also prescribed rocker soles.    Despite regular podiatric and pedorthic care as well as bracing, the patient developed a chronic ulcer inferior to the fourth metatarsal. This is inferior to the area where the patient previously had an osteotomy. The patient has an elevated fourth metatarsal and does not appear to have any palpable pressure at this location. At each office visit, the patient has dried blood within the callus and a shallow ulceration. Multiple attempts to accommodate this area with his orthotic devices have failed.    As a result, video and computer gait analysis was recommended in a few different situations. The analysis included video walking with shoes and braces, pressure mapping with shoes and braces, and pressure mapping with shoes, a brace and accommodative orthotic devices. In this particular situation, pressure mapping software was very important in determining the areas of greatest pressures and the duration of those pressures. Typically in a situation like this, the pressure mapping software would yield the most helpful information. However, in this case, video gait analysis provided the most important clue.    It was evident from the pressure mapping software that there was localized pressure in the region of the ulcer but the pressure was not any greater than what was found in other parts of his foot. However, the integral pressures indicated that the sustained amount of pressure in this one region was much too great. Even though the pressure may not have been an extreme amount, the duration of pressure was causing the problem.    Video gait analysis indicated that the patient, despite wearing braces, exhibited rapid midstance. In other words, his foot landed on the floor rapidly. As soon as his heel contacted the floor, his forefoot would hit the floor at the same time.    The goal of rocker soles is to provide a smoother transition of the foot through midstance into propulsion but this was not the case. This pair of rocker soles was actually contributing to the rapid flatfoot and subsequently elevating the pressures on the ulcerated area. The shape of the heel was acting like a fulcrum, accelerating forefoot loading.    I simply modified his rocker soles by adding a walking heel. Within one month of making this modification, the ulcer healed. While the patient continues to have callus development, there is no longer any dried blood in this region. He has also noticed an improvement in his walking with more comfort.    Providing typical recommendations of orthotic devices, bracing and shoe modifications is very helpful in certain situations but fine-tuning these recommendations may be the difference between a chronic ulcer and a healed wound.

Case Study Three: When Chronic Plantar Fasciitis Returns In An Athlete

   A 40-year-old male complains of chronic plantar fasciitis in his left foot. He says he had this pain for several months. He had a similar episode a few years prior but the use of orthotic devices and injections resolved the condition successfully. However, not only has the plantar fasciitis returned but the patient now has some complaints about his knee and hip on this left side as well. He is a runner and cyclist. He likes to go for at least one two-hour run per week. This has become more difficult as his symptoms became chronic. He understands the importance of wearing good shoes and replaces them often.    A biomechanical examination revealed asymmetry between his lower extremities. The exam noted increased external hip rotation in his right lower extremity and increased internal hip rotation in his left lower extremity. The range of motion in the subtalar joint was also different between the feet. During the exam, I also noted more inversion in the right foot and more eversion in the left foot. The first MTP joint range of motion was also different in each foot. He had functional hallux limitus in his left foot with much less dorsiflexion than in the right foot. Existing orthotic devices fit his feet relatively well. The patient had a Morton’s extension underneath the first MTP joint on each device.    Given this patient’s competitive nature and desire to overcome this injury quickly, I recommended video and computer gait analysis. I performed gait analysis in the following situations: barefoot walking, running shoes with orthotic devices and running shoes without orthotic devices. Both video and pressure mapping yielded interesting and helpful information.    Pressure mapping results indicated significant asymmetry in the force versus time curve. This helped indicate the presence of a leg length discrepancy. The patient had greater pressures on both the first metatarsal head and hallux in the asymptomatic foot. In the symptomatic foot, the mapping noted no first metatarsal head pressure but did note the occurrence of hallux pressures at peak heel strike. This indicated that a functional hallux limitus was contributing to the patient’s complaint. Furthermore, his orthotic devices exacerbated the complaint. These devices were actually increasing the hallux pressures and limiting the range of motion in the first MTP joint even more.    Video analysis showed an in-toed gait on the left side and an out-toed gait on the right. On the left side, the first MTPJ blocked propulsion. This was evident from the side camera view, which showed less hallux dorsiflexion.    After reviewing these findings, I initially sought to modify the existing orthotic devices prior to making new ones. I added a dancer’s pad accommodation to the left orthotic device and placed a wedge under the hallux with the thicker portion proximal and thinner part distal. I placed these modifications onto the orthotic device with meticulous care to their location. The idea is to allow the first metatarsal to plantarflex while elevating the distal portion of the hallux. This should allow for more range of motion during midstance and into propulsion.

Final Thoughts

   Of course, only the successful case studies are illustrated here. Interestingly, a bad outcome with gait analysis is not possible. It is a test that serves to document one’s observations. Based on those observations, one can prescribe a treatment plan that makes sense. That plan may involve proceeding with either conservative or surgical care or even following the effectiveness of the treatment one is currently providing. It is an extremely helpful test that benefits podiatrists and the patients we serve. Dr. Levine is in private practice and is also the director and owner of Physician’s Footwear, an accredited pedorthic facility, in Frederick, Md.

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