Clinical Review
A Profile of Patients in a VA Amputee System of Care Clinic
In the U.S., between 1988 and 1996, surgeons performed 133,235 amputations annually.(1) In 2005, about 1.7 million persons lived with the loss of...
Discussion
The subject of this case report is a physically active traumatic transfemoral amputee who had previous experience with several prosthetic components with the ultimate preference and use of the X2 microprocessor knee. Because of the patient’s desire for the most natural and energy-sparing gait he could achieve, a T2 foot and ankle system was added. Though objective measures of locomotion (LCI) did not change, he reported significant improvement in subjective measures of function and prosthetic acceptance (TAPES).
Reported objective advantages favoring the use of microprocessor prosthetic components most often refer to the decrease in energy consumption during locomotion. Several small studies have compared powered with nonpowered, energy-storing, or passive-elastic components and demonstrated at least modest energy savings. In a study of transtibial amputees, researchers compared oxygen consumption during locomotion in patients fitted with a passive-elastic ankle/foot with patients fitted with the powered T2.3 The researchers reported an average decrease in overall energy consumption of 8.4%. Plantarflexion and p
eak ankle-power production at push-off were both increased. The authors of this study conclude that the T2 ankle/foot allows achievement of greater biological realism.
A 2010 review by Highsmith and colleagues concluded that the microprocessor knee C-Leg demonstrated increased efficacy in safety and energy efficiency compared with other prosthetic knees for transfemoral amputees.4
Subjectively, the study patient reported less fatigue when using the X2/T2 combination than when using the X2 knee without the T2 ankle/foot. It is currently unknown whether the combination provided additive energy savings, and this area would be a good course for future investigation.
The study patient reported several subjective improvements, including reduced back pain, a more natural gait, and improved mobility. Hammarlund and colleagues found a significant prevalence of postamputation lower-extremity back pain compared with preamputation symptoms.5 This pain resulted in at least moderate disability in all subjects during prosthetic use. Morgenroth and colleagues went on to speculate that abnormal lumbar spinal kinematics could be a contributing factor for back pain in transfemoral amputees.6
Though not specifically causative, the study found that those transfemoral amputees with increased lumbar spine transverse plane motion experienced significantly more back pain than did similar amputees without lumbar spine transverse plane motion. An abnormal gait would promote more transverse plane motion than that seen in a normal gait. Normalizing prosthetic gait to best simulate the patient’s preamputation biomechanical baseline could reduce transverse lumbar spine motion, reduce back and other mechanical pain, and ultimately, reduce overall disability.
Similarly, the patient in this study also reported increased ease with hills and stairs. Many studies exist that attest to the advantages of microprocessor knees in providing improvements such as decreased stumbles, increased ability to multitask, increased satisfaction with the prosthesis, and improved stair and stance functions, such as with the Genium (Ottobock).7,8 Whether the combination of a microprocessor knee with a powered ankle/foot would further improve these aspects is yet to be objectively investigated. The report of this study patient who used the combination suggests these types of advantages but certainly as a single case report does not provide definitive answers.
The patient achieved the highest possible score on the LCI before using the X2/T2 combination and thus demonstrated a ceiling effect that has been discussed in several studies.9 Furthermore, Larsson and colleagues noted that because of the ceiling effect, the LCI was more useful for amputees of low to moderate activity levels.10 The TAPES, however, showed an improvement in before and after measurements, and assessment with it was not hindered by a ceiling effect.
Conclusion
The patient in this case report noted substantial subjective functional improvements when using the X2 compared with prior mechanical prosthetic knees paired with the T2 foot/ankle. The functional gains were further verified by significant improvement in the TAPES Index score, a validated measure of prosthetic integration. Specific subjective advantages included energy savings, almost complete resolution of back pain, and improved facility with hills, stairs, and crawl spaces. No perceived disadvantages were reported.
Author disclosures
The authors report no actual or potential conflicts of interest with regard to this article.
Disclaimer
The opinions expressed herein are those of the authors and do not necessarily reflect those of Federal Practitioner, Frontline Medical Communications Inc., the U.S. Government, or any of its agencies. This article may discuss unlabeled or investigational use of certain drugs. Please review the complete prescribing information for specific drugs or drug combinations—including indications, contraindications, warnings, and adverse effects—before administering pharmacologic therapy to patients.