Gait and Posture 10 (1999) 206–210 Botulinum toxin A in hamstring spasticity I.S. Corry a, *, A.P. Cosgrove a , C.M. Duffy a , T.C. Taylor a , H.K. Graham b a Department of Orthopaedic Surgery, Royal Belfast Hospital for Sick Children and Musgrae Park Hospital, Belfast BT97JB, N. Ireland, UK b Department of Orthopaedic Surgery, Royal Children’s Hospital, Melbourne, Vic., Australia Received 8 December 1997; received in revised form 3 June 1999; accepted 21 July 1999 Abstract Hamstring injection of Botulinum toxin A (BtA) may have a role in the conservative management of flexed knee gait in cerebral palsy or in simulating the effect of surgery. Ten children who were likely to require future hamstring lengthening were injected. Short term outcome was assessed by clinical examination and 3-D gait analysis. Mean popliteal angle decreased by 16° and maximum knee extension in stance increased by 8°, the latter relapsing by 12 weeks. Mean pelvic tilt tended to increase suggesting that isolated hamstring weakening be approached with caution. Energy cost of walking was not significantly changed in six of the ten patients. A small increase in knee extension in stance was often associated with patient satisfaction. There are theoretical grounds for expecting an associated increased longitudinal muscle growth after BtA injection. © 1999 Elsevier Science B.V. All rights reserved. Keywords: Botulinum toxin; Cerebral Palsy; Hamstrings; Spasticity; Gait www.elsevier.com/locate/gaitpost 1. Introduction Surgical lengthening of the hamstrings may be indi- cated if the knee flexion deformity is greater than 15° during the stance phase of gait [1]. Additional indica- tions might be an increase in hamstring tone and an increased popliteal angle, however causes of flexed knee gait other than hamstring shortening need to be consid- ered [2]. Energy cost of crouch gait should also be borne in mind; for example immobilising the knee at 45° flexion in normal individuals can cause a 37% increase in the energy cost of walking [3] and any intervention should inadvertently increase the energy cost of walking. Hamstring injection of Botulinum toxin A (BtA) may have a role when hamstring spasticity is the dominant cause for gait abnormality. Further indications might be: (a) as an adjunct to other surgery (e.g. calf tendon lengthening) to help prevent crouch; (b) in combination with injection of calves/adductors in assisting conserva- tive management to delay surgery until the appropriate age; and (c) to simulate the effect of hamstring length- ening in a reversible way to help with the surgical decision-making. To our knowledge, there has been no previous published series on the effect of isolated ham- string injection of BtA. This study set out to test the following hypotheses: (1) botulinum injection into hamstring muscles can change gait kinematics in the cerebral palsy patient, leading to an improved pattern of walking; and (2) change in gait pattern caused by injection of Botulinum toxin does not increase the energy cost of walking. 2. Method Ten children with cerebral palsy of mean age 7.2 (range 4–11) years and with a dynamic component to hamstring spasticity were selected, as a convenient sam- ple from the Orthopaedic outpatient clinic and offered hamstring injection of BtA. The target group was those who were likely to require future hamstring lengthening but had not yet reached the point at which surgery was clearly indicated or accepted by the parents. Six chil- dren had diplegia, one had hemiplegia and three had quadriplegia. None had had previous surgery or injec- tion for hamstring spasticity or shortening. There were * Corresponding author. Tel.: +44-1232-669501; fax: +44-1232- 661112. 0966-6362/99/$ - see front matter © 1999 Elsevier Science B.V. All rights reserved. PII:S0966-6362(99)00037-5