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Case Report

Functional Outcome Measurements of Bilateral Custom Knee Orthoses to Treat Hypermobility and Instability in Ehlers-Danlos Syndrome Type I: A Case Study

Sardó, Keith R. BS, CPO

Author Information
JPO Journal of Prosthetics and Orthotics: July 2012 - Volume 24 - Issue 3 - p 133-137
doi: 10.1097/JPO.0b013e31826284bc
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Ehlers-Danlos syndrome (EDS) is a rare hereditary connective tissue disorder characterized by hypermobile joints and skin that can be both hyperextensible and fragile with frequent subcutaneous hemorrhages.1 There are six identified types of EDS with varying degrees of collagen defect. Type I (classic) is characterized by severe and generalized joint hypermobility, severely fragile skin, severe subcutaneous hemorrhaging, and severe skin hyperextensibility. The heredity of type I is autosomal dominant and may feature arterial ruptures in some extreme cases.1–3

Although much has been reported on the etiology and complications of EDS, little has been discussed on proper daily treatment and symptom management of EDS. Exhaustive PubMed and Google Scholar literature searches yielded several articles that mentioned the use of orthoses as part of the patient history but no articles that studied the effectiveness of using orthoses as treatment for hypermobility and instability associated with EDS.

The purpose of this case study was to report the functional outcomes of the use of bilateral custom knee orthoses to treat lower limb hypermobility and instability in a woman with EDS type I.

PATIENT HISTORY AND EXAMINATION

The patient is a 39-year-old woman on medical leave as a registered nurse with chronic rheumatologic problems including joint dislocations, hypermobility, and chronic pain. Her dermatologic problems include hyperextensibility, easily experiencing subcutaneous hemorrhages, and characteristically smooth “velvety” skin. Her history included a fall approximately 1 year before orthotic intervention, which resulted in many injuries including a torn right medial-collateral ligament, a torn right meniscus, a torn right deltoid ligament, a torn right posterior-cruciate ligament, bilateral posterior tibial tendon dysfunction (PTTD), bilateral failed ankle surgery to address her PTTD and torn deltoid ligament, and unspecified joint dislocations. At the time of her initial evaluation, she was 24 weeks pregnant, and she experienced a ventral hernia after the birth of her child. An orthopedist referred her to the author because of the author’s history of stabilizing patients’ joints with orthoses in other patients with hypermobility conditions. The patient arrived wearing a right over-the-counter neoprene knee sleeve and a walking boot to be replaced with a custom knee-ankle-foot orthosis (KAFO) to provide knee and ankle stability during her pregnancy. She wore a right custom, drop-lock, double-adjustable ankle-joint (anterior stop at 90° and posterior spring), plastic KAFO successfully with a decrease in her symptoms and an increase in her stability for 10 months until she was diagnosed with EDS. At the time of her EDS diagnosis, she had delivered her child, the PTTD had healed, she had lost 40 lb, and her primary complaint was bilateral lower limb instability specifically at the knees, especially without the KAFO.

Clinical examination and manual manipulation revealed bilateral coronal knee instability into both varus and valgus where the valgus instability was the greater concern. Anterior and posterior drawer tests were hypermobile (1 cm), but her orthopedist reported negative for tears on magnetic resonance imaging. Her genu valgum measured 12° bilaterally, and hyperextension measured 10° bilaterally (weight bearing).

METHODOLOGY

CUSTOM KNEE ORTHOSES

The author took plaster impressions of the patient’s lower limbs to fabricate custom knee orthoses. The knee orthoses were fabricated at Townsend Design (Bakersfield, CA, USA) without their knowledge of this study (Figures 1 and 2). Bilateral knee orthoses of the Reliever Air model were fabricated for this patient to provide her maximum control of her range of motion. The Reliever Air model is adjustable and can limit the amount of genu varum, genu valgum, and hyperextension allowed under weight bearing. This model can also apply pressure to correct or reduce coronal angular deformities. The Reliever Air model has a larger surface area to distribute pressure, which is especially important for patients with EDS to prevent subcutaneous hemorrhaging. The custom knee orthoses were also fit and adjusted by the author.

Figure 1
Figure 1:
Full Shell Reliever Air custom knee orthosis, anterior view. Courtesy of Townsend Design.
Figure 2
Figure 2:
Full Shell Reliever Air custom knee orthosis, lateral view. Courtesy of Townsend Design.

The patient wore the custom knee orthoses daily throughout the 15-week period. She donned them in the morning when getting dressed and doffed them at the end of the day before she went to sleep. She was questioned each visit about her wear time and she reported wearing them 12–16 hrs a day. The variance is accounted for when she removed them for naps or long periods of non-weight-bearing rest. She continued receiving the physical therapy she had begun before orthotic intervention. She also had her gallbladder removed at week 12.

DATA COLLECTION

Functional outcomes were measured by performing the timed up and go (TUG) test4,5 and the Locomotor Capabilities Index (LCI).6 Both were measured before the patient received the custom knee orthoses and at every follow-up appointment over the subsequent 3 months. The TUG test was performed with and without the orthoses at each appointment. The LCI was completed in reference to how the patient felt she was able to complete the activities, then, while wearing the orthoses.

PROCEDURE

The TUG test was performed from an armed chair with an 18-in seat height and a 25-in arm height. The patient was seated on the chair with her back resting against the back of the chair. On the verbal command “go,” the patient stood in a self-selected manner, walked 3 m to a mark on the floor, turned around, returned to the chair, and sat down. The timer began at the verbal command and stopped when the patient was fully seated with her back against the chair. The event was timed with the same standard digital timer at each appointment and was calculated to tenths of a second. Three trials were performed and recorded without the orthoses (Table 1), then averaged for her daily time. She was allowed to rest 5 minutes and then three trials were performed and recorded with the orthoses (Table 2), then averaged for her daily time. To eliminate the desire to perform, the patient was not allowed to see her previous scores.

Table 1
Table 1:
Timed up and go test (in seconds) without custom knee orthoses
Table 2
Table 2:
Timed up and go test (in seconds) with custom knee orthoses

The LCI was completed by the patient at every appointment with the author (Figure 3). The instructions and scale descriptions were given each time. The patient was asked to rate her ability to perform “basic activities” and “advanced activities” at that point in her treatment, and she rated them on a scale of 0 to 3. A score of 0 meant she was not able to do the described activity at all. A score of 1 was defined as the patient being able to do the described activity with assistance. A score of 2 was defined as the patient being able to do the described activity with supervision. This score indicated she was able to do the activity independently but that she did not feel safe enough to do it without someone guarding her and ready to provide assistance as needed. A score of 3 was defined as the patient being able to do the described activity independently and safely (Table 3). To eliminate the desire to perform, the patient was not allowed to see her previous scores.

Table 3
Table 3:
Locomotor Capabilities Index
Figure 3
Figure 3:
Locomotor Capabilities Index.

DATA ANALYSIS

Scores for both tests were calculated by the author, including the mean and standard deviation for each set of TUG tests, the sum of the LCI totals, and the percentage change for the TUG tests and LCI from the initial visit before orthotic intervention to the end of the 15-week period both with and without the knee orthoses.

RESULTS

Table 2 shows TUG test times recorded at initial evaluation (week 1), at the fitting (week 2), and at the 1-month (week 4) and 3-month (week 15) follow-up. Table 3 shows the LCI scores for the same weeks. The patient showed a 21.7% improvement in her TUG test with the knee orthoses over the 15 weeks observed. Interestingly, she showed a 16.7% improvement between week 4 and week 15 without the orthoses, but no substantial improvement before week 4. A 105.6% improvement was recorded in her LCI score. At week 4, the custom knee orthoses were adjusted to reduce her genu valgum from a Q-angle of 12° to 7°. This helped improve the fit, and she reported an increased sense of stability (Figures 1 and 2).

DISCUSSION

The TUG test and the LCI were chosen because of their reliability and ease of use in a clinical setting.7–9 The TUG test has been used to determine the effectiveness of orthoses (ankle-foot orthoses) in patients with chronic stroke.10 It has also been used as a measure to determine risk of falling. In a healthy geriatric population, TUG test times of 15 seconds or more indicate a greater risk of falling.11 In a status post hip fracture population, TUG test times of 24 seconds or more indicate a greater risk of falling.12 The TUG test has found that adults without balance problems could complete this test in under 10 seconds, and those dependent in most activities of daily living and mobility skills required more than 30 seconds.13 The time taken to complete the TUG test varies with the use of an assistive device, but it is capable of distinguishing elderly persons who have balance problems from those who do not.14 What is notable about the TUG test in comparison with metered walking tests is that in involves standing-from-sitting, balance, walking, turning while walking, coming to a stop, and sitting-from-standing. This encompasses more measures of mobility than a simple walking test does, which measures only speed between two points after the patient has already started walking, and walking tests often do not include standing, stopping, or sitting. Therefore, the TUG test provides an objective measure to correlate functional changes in the patient’s mobility—specifically regarding speed, mobility, balance, fall risk, and functional dependency.

The patient’s initial TUG test time of 12 seconds was below that of the pathologic and geriatric populations11,12; however, the times were still slower than normal values for a healthy population.13 No normative values exist for her age group, but the closest is 60 to 69 years at 7.1 to 9.0 seconds.15 When compared with the mean time of other patient populations, her time of 12 seconds was closest to the chronic cerebral vascular accident population (13.7 seconds), the cerebral palsy Gross Motor Function Classification System level II population aged 5 to 12 years (13.2 seconds), and the multiple sclerosis population (13.9 seconds).16 Her time was also slower than the mean values of many populations, including most of the cerebral palsy population (see article), the traumatic brain injury population ages 7 to 12 years (9.0 seconds), and the post-polio population (9.0 seconds).16

VALIDITY

The LCI has been used only with prostheses and has not been used or validated for use with an orthosis; however, the author proposes that the LCI translates well to orthoses because 1) the questions do not specifically reference the function of a prosthesis but rather activities of daily living and 2) the purpose of the LCI is to assess the patient’s self-perceived ability to perform a task with the assistance of a device that replaces a physical functional deficit—and both orthoses and prostheses accomplish this purpose.

FUNCTIONAL OUTCOMES

In the patient’s initial LCI, she answered 9 of the 14 questions (64.3%) with a score of 1 or 0, indicating a lack of functioning independently and/or safely a majority of the time. Over the 15-week period, 100% of the nine questions improved to a score of 2 or 3, indicating a substantial increase in her perceived stability and independence. She answered 4 of the 14 questions (28.6%) with a score of 0, indicating she was completely unable to do the indicated activity. Over the 15-week period, 100% of the four questions improved to a 2 or 3, indicating a noteworthy change in her perceived stability and independence. In the final scoring, there were no scores of 0, and 100% of the activities were scored in the independent range of 2 to 3, and 9 of the 14 activities were scored as a 3, indicating complete independence. Overall, there was a remarkable 105.6% increase and improvement in her total score—and therefore, her perceived stability and independence—after receiving the custom knee orthoses.

It is reasonable to draw comparisons between the LCI and TUG test. The immediate benefit of wearing the custom knee orthoses was observed in immediate improvements in both scores. As the patient reported in the LCI that she was more stable, safer, and independent with the orthoses, she then walked faster in the TUG test. Conversely, without the orthoses, she perceived that she was less stable, less safe, and less independent, and therefore, her TUG test times were slower. A correlation can be drawn that using an orthosis for patients with hypermobility, as in EDS, increases their perceived stability, safety, and independence and that perceived improvement correlates to increased speed and mobility.

LIMITATIONS

Limitations of this study include the unknown effects of weight loss, the patient’s pregnancy, and the unknown effects of the physical therapy she received. The hormones released during pregnancy to increase the laxity of the symphysis pubis for childbirth may have an unknown lasting effect on other ligaments in the body, and there is no measure in this study to determine the effect. There is no measurement in this study to quantify the amount of improvement gained due to the orthoses versus the therapy or the effect of the combined treatments. Individual nuances of EDS would need to be evaluated on a patient-by-patient basis. For example, some patients with EDS may need ankle stability instead of knee stability, and the results demonstrated here may offer only an indirect correlation when involving instability of a different joint. Standard clinical judgment and contraindications for any orthosis would apply with emphasis and caution about the propensity for patients with EDS to easily experience subcutaneous hemorrhages.

CONCLUSION

The patient with EDS type I in this case study showed improvement in TUG test times and the self-assessment LCI. The patient showed improvement in her gait speed and mobility and her perceived stability, independence, and safety when fit with bilateral custom knee orthoses and measured with the TUG test and the LCI. These improvements indicate a substantial medical benefit for patients with hypermobility and instability of the knee, such as seen with EDS, to be treated with custom knee orthoses to increase their speed and mobility and their perceived stability, independence, and safety.

Further studies should measure the long-term effects and any potential cumulative effects over a larger patient population. The benefits of modified versions of the TUG test and LCI17,18 should also be considered.

REFERENCES

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Figure
Keywords:

Ehlers-Danlos syndrome; custom knee orthoses; timed up and go test; Locomotor Capabilities Index

© 2012 by the American Academy of Orthotists and Prosthetists.