Prosthetic Prescription for an Obese Patient: A Case Report

Following amputation, individuals often experience significant psychological challenges, including depression and decreased motivation to move, which often lead to a more sedentary lifestyle, weight gain, and ultimately obesity. Obesity is a risk factor for comorbidities including diabetes, heart disease, and stroke, but for patients with amputation, these risk factors take on added significance.^1,2 Obesity may increase the risk of overuse injuries such as tendinitis, plantar fasciitis, and osteoarthritis, which are significant to the prosthetic prescription.³ The complications that obesity introduces to the prosthetic fitting process pose specific difficulties for the prosthetist. Excess residual-limb soft tissue results in a less secure fit because there is no firm foundation-no bony lock-for the prosthetic socket. Excess rotation and pistoning of the soft tissue results in less control over the prosthesis and poor stability. Volume management is an issue for all individuals with amputations, but amputee patients who are obese experience significant volume fluctuations resulting in poor socket fit, and, more often than not, clinics are unable to receive reimbursement from third-party payers for the number of socket replacements needed to accommodate these volume changes and properly fit the patient's residual limb over time. There are limited component options for patients who are overweight, and these components are generally more expensive and need frequent repair.⁴ Finally, the patient may not be at the functional level required for device reimbursement.

Despite the challenges of prescribing a prosthesis to an obese patient, success is possible. It is important to start rehabilitation and ambulation as soon as possible after amputation-especially for patients who are nonambulatory prior to amputation-to help avoid additional weight gain.⁵ While some research suggests that once a prosthetic prescription has been filled, obese patients are more likely to experience functional deficits than those who are not obese, it is unclear what functional abilities patients who are non-ambulatory at prosthetic prescription could eventually achieve.² Mueller et al.'s research indicates that obesity is not necessarily a predictor of failure with a transfemoral prosthesis. Of nine criteria investigated in the Mueller study, only compliance and medical problems after prescription resulted in a significant difference between successful and unsuccessful longterm outcomes for transfemoral prosthesis users.⁶

This report documents the success of a highly motivated, morbidly obese woman through her prosthetic rehabilitation. The objectives of this study were to develop strategies to improve outcomes for obese patients and investigate how compliance influences prosthetic success.

Case Presentation

The subject is a 58-year-old female, who is five feet, four inches tall and has a distal residual-limb circumference of 67cm. The patient had a failed knee replacement surgery with multiple infections at the surgical site two years prior to her transfemoral amputation in May 2011. She does not have diabetes and does not smoke or drink alcohol. She injured her rotator cuff in 2010 as the result of a fall. She presented with edema and osteoarthritis in her contralateral limb. The patient lived in a one-story home with her husband prior to her amputation. Following amputation surgery, the patient weighed 310 lb. (140.61kg) and was moved to a skilled nursing facility (SNF). The patient's hobbies include decorative painting and sewing, which she would like to resume. She is highly motivated and expressed a desire to resume doing housework and going grocery shopping.

Treatment

The patient contacted Dayton Artificial Limb Clinic, Ohio, two months after her amputation. The patient had been attending one-hour physical therapy sessions at a rehabilitation facility twice a day, five days a week. Each month, she and her physical therapist set new goals and reassessed what she wanted to accomplish. Ultimately, her goal was to resume completing her activities of daily living (ADL) independently. Within the first three months of the patient's prosthetic treatment at Dayton Artificial Limb Clinic, three different prosthetic prescriptions were attempted. The subject's functional outcome was measured with each prescription, and the prosthetist made changes based on the results.

Assessment Tools

The physical therapist measured the patient's functional progress at intervals throughout the rehabilitation process to evaluate the effects of different prescriptions. Three functional tests were administered: the Locomotor Capabilities Index-5 (LCI-5), the Instrumental Activities of Daily Living (IADL), and the Amputee Mobility Predictor (AMP).

The LCI-5 is a questionnaire that asks the patient to rate his or her ability to perform functional tasks such as stepping off a sidewalk curb or walking up steps using a handrail.⁷ The LCI-5 has good internal validity and test-retest reliability.^8,9,10 While it is useful in helping to determine the types of rehabilitation interventions to be used, it does not provide an accurate assessment of community mobility, so it must be used in conjunction with other assessments.⁸ The IADL is a questionnaire that measures the ability of an individual to care for himself or herself independently and is useful in assessing everyday functional competence.¹¹ The AMP is an assessment tool that rates a patient's ability to perform a series of tasks, such as reaching for an object and stepping over an obstacle. The score is based on performance regardless of whether an assistive device is used. It is comparable to the six-minute walk test and is a valid measure of amputee ability with or without a prosthesis.¹² It can be used repeatedly in the clinical or research setting to monitor functional improvement.¹³ The AMP score determines the patient's functional level, or K-level.

The patient's functional assessment scores, K-level, and weight were recorded at intervals throughout the prosthetic prescription process.

Prosthetic Solutions

Figure 1

Figure 2

Prior to coming to Dayton Artificial Limb Clinic, another area prosthetic clinic had provided the patient with a shrinker. Wounds had appeared on the patient's residual limb due to tissue mass and shrinker migration. Immediately following the prosthetic evaluation at Dayton Artificial Limb Clinic, the patient was evaluated for and provided with a new shrinker (Juzo, via PEL Supply) to help control the edema in her residual limb; however, she was unable to don it due to lack of core strength, short upper limbs, and abdominal mass. A few days later, her prosthetist provided her with a silicone liner (SealMate, Prosthetic Design Inc.) and instructed her to wear it for one to two hours, three times a day.

Prosthesis #1

The prosthetist designed the patient's first prosthesis to provide stability as the patient began weight bearing in the first three months of prosthetic use (Figure 1). The single wall, no liner, transfemoral suction socket prosthesis was fabricated using transfemoral measurements. When un-weighted, it would break suction. While the patient could not ambulate with this prosthesis due to the inadequate suspension, she could stand and weight bear for three to five minutes at a time. She had moderate to maximum assistance with sitting and standing, which she could do about three times per day. This was the first time in eight years that the patient had been able to stand and weight bear on both lower limbs. Her LCI-5, AMP, and IADL scores were one, zero, and five respectively. She weighed 312 lb. (141.52kg). These scores put her in the K0 range. According to the LCI-5, the subject was barely able to do basic tasks, even with assistance.

Prosthesis #2

The second prosthesis consisted of an Orfitrans® Stiff (37ST/44150) socket (Orfit Industries) fabricated based on transfemoral measurements (Figure 2). This socket did not use a liner; however, a harness was added to help the patient don and doff the prosthesis. This prosthesis was provided to the patient after one month of using the first prosthesis. She could not independently don the prosthesis due to her pendulous abdomen; however, she could doff the prosthesis independently. The patient reported that the harness was an improvement because it did not make her feel like she was going to drop the prosthesis. Her limb volume continued to reduce, and her strength, endurance, and range of motion increased. She required only moderate assistance when standing in the parallel bars. Her LCI-5, AMP, and IADL scores were ten, ten, and seven, respectively, and her weight dropped to 298 lb. (135.17kg). The subject remained at the K0 level. According to the LCI-5, the subject was able to do basic tasks alone with aids and advanced tasks with assistance.

Figure 3

Prosthesis #3

The patient's third socket was a total surface bearing cast, single-wall, suction socket (Figure 3). She was cast while in a supine position because she could not bear weight unilaterally for the cast to be taken standing. The supine casting allowed soft tissue displacement and capture of the residual-limb volume. The patient said she was excited about how well the socket fit. A donning pump (Ladon Systems) was used to pull tissue farther into the socket and improve the suction fit. This donning pump provided increased security and attachment of the prosthesis to the residual limb. At the first appointment with this socket, she was able to walk a few steps in the parallel bars for the first time in eight years. After one month, she was able to ambulate 75 ft. (22.86m) in the hallway using a walker, taking breaks about every 20 ft. (6.10m). Four days after receiving the new socket, her LCI-5, AMP, and IADL scores were 16, 20, and four respectively. These test results placed her at the K1 level. According to the LCI-5, she was able to do basic tasks if someone was close and advanced tasks with assistance. Her weight remained at 298 lb. (135.17kg).

Outcome

Three months after her amputation, the patient was discharged from the SNF and returned home. She received home physical and occupational therapy twice a week for five weeks and did independent exercises twice a day. Her goals were to make her bed every morning and wear the prosthesis more often. She is now able to unload the dishwasher, put the laundry away, and walk up and down the ramp in front of her home. She wears her prosthesis for approximately three hours per day. After six months with the new socket, her LCI-5, AMP, and IADL scores were 20, 22, and five, respectively, placing her at the K1 level. Her weight decreased to 282 lb. (127.91kg). According to the LCI-5, the subject was able to perform basic tasks alone with aids, and advanced tasks when someone was nearby.

Discussion and Conclusion

Three prosthesis designs were fabricated for this patient, and adjustments were made to create a better fit for the patient. The prostheses that this patient was fitted with were not standard or customary. The prosthetist, physical therapist, and patient collaborated to develop a solution that would allow the patient to don and doff the prosthesis independently, which increased her quality of life. Prosthetic components were chosen to give the patient the best chance at a positive functional outcome.¹⁴ The quick feedback from the patient and the physical therapist about each intervention provided valuable input about how to improve the prosthesis.

The patient's functional tests scores increased during her prosthetic treatment, and her weight decreased by 28 lb. (12.70kg). Initially, the patient experienced a decrease in motivation at home because she could not yet accomplish all of the tasks she wanted to. Not surprisingly, this resulted in a slight decrease in her function; she relied more on her wheelchair than she did on her walker. However, once the patient gained more confidence with her prosthesis, she began relying more on her walker, and her physical function increased. She had excellent compliance, which gave her the best chance of achieving a positive outcome.⁶ The patient's functional ability increased from K0 to K1 over the course of seven months, and while she has not yet resumed her hobbies, she says that she plans on doing so soon. She has started doing light housework, including folding laundry, loading and unloading the dishwasher, and food preparation.

This patient was highly motivated and had a successful prosthesis fitting, but more studies are needed to document the prosthetic fitting process of patients with obesity and their outcomes.

Erin Sutton, BME, has been a clinical researcher at Dayton Artificial Limb Clinic and a research and development co-op at Prosthetic Design Inc. (PDI), both in Dayton, Ohio, for the last three years. Erica Gaussa (University of Dayton) is a development co-op at PDI. Samantha Staubach (University of Cincinnati, Ohio) is a biomedical engineering co-op at PDI. Lucinda Busch, CP, has been a prosthetist at Dayton Artificial Limb Clinic since 1996.

References

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