Evaluation of extensibility, passive torque and stretch reflex responses in triceps surae muscles following serial casting to correct spastic equinovarus deformity.

Barby Singer, Kevin Singer, Garry Allison

Research output: Contribution to journalArticlepeer-review

15 Citations (Scopus)

Abstract

Primary objective: Spastic equinovarus deformity of the ankle in adults with acquired brain injury can severely limit the achievement of rehabilitation goals. This study examined changes in triceps surae muscle extensibility, passive resistive torque and soleus stretch reflex responses in 10 adult brain injured subjects undergoing serial casting to correct ankle equinovarus deformity.Method: Goniometric measurement of maximal passive dorsiflexion was used to evaluate extensibility of the triceps surae muscles. Computer controlled ankle dynamometry and surface electromyography were used to identify passive resistive torque and soleus stretch reflex onset angle in response to stretches at two velocities.Results: The mean casting period was 5 weeks. Casting was discontinued in one subject due to failure to achieve measurable gain in ankle range over three consecutive cast changes. Median improvements in maximal ankle dorsiflexion, with the knee flexed or extended, of 30degrees and 15degrees, respectively, were achieved in the remaining nine subjects (p < 0.0001). The median passive ankle range in response to a displacing torque of 10 Nm increased 4.3&DEG; over the intervention period (p < 0.0001). Consistent soleus reflex activity in response to passive stretches at 25degrees.s(-1) was elicited in only four subjects. A trend for the stretch reflex onset to move further into the available range was demonstrated in these subjects.Conclusion: In the present study, serial casting contributed to significant change in triceps surae extensibility and passive resistive torque, corresponding with improved maximal passive ankle dorsiflexion range and an increase in the angle achieved with a displacing torque of 10 N.m. Increased stretch reflex threshold was observed in some subjects. The use of pre-determined outcome criteria and careful measurement of responses to this intervention were important to prevent premature discontinuation of casting when gains were slower than expected.
Original languageEnglish
Pages (from-to)309-24
JournalBrain Injury
Volume17
Issue number4
DOIs
Publication statusPublished - 2003

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