Effect of Achilles tendon lengthening on ankle muscle performance in people with diabetes mellitus and a neuropathic plantar ulcer

Background and Purpose. The effect of a tendo-Achilles lengthening (TAL) procedure on ankle muscle performance has not been clearly established. The purpose of this study was to compare the effects of TAL and total-contact casting (TCC) with TCC alone on ankle muscle performance in subjects with diabetes mellitus (DM) and a neuropathic plantar ulcer. Subjects. Subjects were randomly assigned to either a TAL group (3 female and 12 male subjects) or a TCC group (4 female and 10 male subjects). Methods. Muscle performance measurements were obtained using an isokinetic dynamometer. Results. Concentric plantar-flexor peak torque decreased 31% after TAL but returned to the baseline level after 8 months. Dorsiflexor peak torque did not change in either group. Plantar-flexor passive torque at 0 degrees of dorsiflexion decreased after TAL but increased to 60% of the baseline level after 8 months. Maximal dorsiflexion angle increased 11 degrees after TAL and remained increased at 8 months. Discussion and Conclusion. The TAL resulted in an increase in ankle dorsiflexion range of motion and a temporary reduction in concentric, plantarflexor peak torque and passive torque at O degrees of dorsiflexion. If TAL is being considered for people with DM and a neuropathic forefoot ulcer, the initial compromise in plantar-flexor muscle performance should be addressed.