Botulinum toxin type A injections for the management of flexion contractures following total knee arthroplasty.

The development of knee flexion contractures following total knee arthroplasty is detrimental to a patient's functional capabilities. Despite using aggressive rehabilitative modalities postoperatively, some knee arthroplasty patients do not respond and continue to experience muscle spasms. Botulinum toxin type A has been used as a temporary neuromuscular transmitter blocker to treat muscle spasms in patients with neurological disorders, and it has been utilized as a treatment method for clubfoot. The purpose of this study was to evaluate botulinum toxin type A as a new treatment modality for patients with flexion contractures following total knee arthroplasty that were recalcitrant to standard treatment methods. By 2 years following injections, 9 out of 11 knees achieved extension within 10; of neutral position, and 8 of the 11 maintained this improved range of motion by a mean follow-up of 36 months. There were two failures in patients who had a revision knee arthroplasty, suggesting that this treatment is more effective in patients following primary cases. Based on these results, botulinum toxin type A should be considered as a potential treatment modality, especially in difficult-to-treat cases of knee flexion contracture that are recalcitrant to standard therapy.