Variations in knee range of motion during repeat knee extension with an amputated lower leg at different contraction rhythms over 8 consecutive days in a patient with severe diabetic neuropathy: A clinical study

Abstract

Background: This clinical study sought to understand the knee range of motion (KROM) in an amputated stump during repeat voluntary knee extension with or without a 0.5 kg weight in the acute/early phase after amputation can vary between different target knee extension rhythm frequency (KER) levels in the amputated lower leg of a patient with severe diabetic sensory disorder and leg ischemia. Case Presentation: A 51-year-old male patient with severe diabetic neuropathy had a right lower leg amputation due to necrosis and ulcer lesion following a burn injury to the first toes and severe ischemic peripheral vascular disease. In a sitting position with the base of the foot of the non-amputated left leg on the ground, he performed repeat knee extension of the resected stump (knee active extension and passive flexion without a target KROM) for 1 min with both self-controlled free KER and different target KERs (30, 40, 50, 60, and 80 contractions per minute [cpm] using a metronome), with or without a 0.5 kg weight placed on the resected stump over 8 consecutive days. The KROM was measured using a goniometer placed between the resected stump and the thigh muscle with a continuous data acquisition system. The mean values achieved for KER, KROM, and angle rate during a 1 min session was determined during each daily session, and consecutively average values over sessions on 8 consecutive days was also evaluated. The achieved mean KER at all target KERs corresponded closely with the target KER. The average KROM was approximately 60 degrees over a range of targets between 30 and 60 cpm, but the value was lower at approximately 50 degrees at 80 cpm. The angle rate increased consistently with the increase from a target of 30 to 60 cpm, but it was reduced at 80 cpm. The mean KROM was inversely related (r=-0.390, P<0.01, n=40) to the mean KER without the weight, but not significantly (r=-0.256, P=ns, n=40) with the 0.5 kg weight. The achieved KER in the self-controlled free trial with or without the 0.5 kg weight might increase with an increase in sessions over 8 days with a range between approximately 30 and 60 cpm. Conclusion: The present case study showed that a higher contraction frequency may limit KROM determined below 60 cpm because of the reduced angle rate in an amputated lower leg. A low and moderate KER below 60 cpm may be appropriate to maintain KROM with a stable angle rate. Furthermore, voluntary KER with free self-controlled rhythm may increase over the course of multiple sessions as familiarity improves with kicking the amputated limb and generating a potential improvement in performance/ability effect with consecutive leg exercise with no use of a prothesis such as in the early/acute phase post-amputation using audible biofeedback.