vendex and Poliomyelitis

The goal of this study was to investigate clinically relevant biomechanical conditions relating to the setup and alignment of knee-ankle-foot orthoses and the influence of these conditions on knee extension moments and orthotic stance control during gait. Knee moments were collected using an instrumented gait laboratory and concurrently a load transducer embedded at the knee-ankle-foot orthosis knee joint of four individuals with poliomyelitis. We found that knee extension moments were not typically produced in late stance-phase of gait. Adding a dorsiflexion stop at the orthotic ankle significantly decreased the knee flexion moments in late stance-phase, while slightly flexing the knee in stance-phase had a variable effect. The findings suggest that where users of orthoses have problems initiating swing-phase flexion with stance control orthoses, an ankle dorsiflexion stop may be used to enhance function. Furthermore, the use of stance control knee joints that lock while under flexion may contribute to more inconsistent unlocking of the stance control orthosis during gait.

Topics: Adult; Ankle Joint; Braces; Equipment Failure Analysis; Foot; Gait Disorders, Neurologic; Humans; Knee Joint; Male; Muscle Contraction; Poliomyelitis; Prosthesis Design; Range of Motion, Articular; Torque; Treatment Outcome

To evaluate the muscle strength of the lower limbs over time in polio survivors during 5 years of follow-up and to examine the rate of change in their muscle strength, we performed a prospective, longitudinal study of polio survivors (n = 63: 61 with postpolio syndrome) living in the community who participated voluntarily. Their isokinetic knee-extensor and knee-flexor muscle strength (peak torque) at angular velocities of 60 and 120 deg/sec, using a fixed dynamometer (Biodex) were measured over a 5-year period. At 5-year follow-up, approximately 90% of the subjects had decreased knee extensor strength at both angular velocity of 60 and 120 deg/sec: similarly, at both angular velocities, approximately 80% of the subjects had decreased knee flexor strength. The annual average rate of decrease in the peak torque of the knee extensors was significantly greater than that of the flexors at both angular velocities, and the difference in the rates between the extensors and the flexors was marked at the faster angular velocity. The polio survivors had a progressive decrease in lower limb isokinetic muscle strength over time. In addition, the annual rate of decrease of the knee-extensor, the so-called weight bearing muscle, was greater than that of the knee-flexor.

Topics: Adult; Aged; Female; Follow-Up Studies; Humans; Knee; Leg; Longitudinal Studies; Male; Middle Aged; Muscle Strength; Muscle Strength Dynamometer; Muscle, Skeletal; Poliomyelitis; Postpoliomyelitis Syndrome; Prospective Studies; Torque

Twenty-one subjects with polio 24 to 51 years prior to the first examination were studied on three occasions, each 4 years apart with measurements of muscle strength and endurance for knee extension, macro EMG, and muscle biopsy from vastus lateralis. On average the muscle strength decreased during the 8-year follow-up by 9-15%. Endurance decreased during the observation period. The muscle fiber area was markedly increased in most subjects. There was a decrease in the capillarization during the follow-up. Macro EMG was increased in all subjects (range 3-42 times control) and increased in 20 legs during the 8-year follow-up, but showed a decrease in 8 of 9 legs with an approximative breakpoint when macro MUPs were around 20 times the normal size. Thus, evidence of on-going denervation/reinnervation as well as of failing capacity to maintain large motor units was demonstrated. SFEMG showed a moderate degree of disturbed neuromuscular transmission.

Topics: Adult; Aged; Biopsy; Citrate (si)-Synthase; Electromyography; Female; Humans; Knee Joint; Longitudinal Studies; Male; Middle Aged; Motor Neurons; Muscle Contraction; Muscle Fibers, Skeletal; Muscle Weakness; Muscle, Skeletal; Physical Endurance; Poliomyelitis; Torque