Collagenase Use and a Trap for the Unwary in Patients With Upper Limb Spasticity.

Collagenase has revolutionized the treatment of Dupuytren's disease. It acts by lysing collagen in Dupuytren's cords. It can also act on collagen in tendons, leading to tendon rupture. In this letter, we highlight caution where bowstringed flexor tendons were masquerading as Dupuytren's cords in a patient with upper limb spasticity. The initial plan was to inject the cords with collagenase; however, we proceeded with an open approach. If we had proceeded with our initial plan to inject the palpable cords with collagenase, tendon rupture would have been the likely outcome. We advise that administrators of collagenase proceed with caution in patients with upper limb neurological disorders, bearing in mind that bow-stringed flexor tendons can mimic Dupuytren's cords.