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

Abstract

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.

Tips and Pearls

Collagenase has revolutionized the treatment of Dupuytren’s disease over the last 10 years since the CORD 1 study. ¹ It acts by lysing type I and type III collagens, which are found in Dupuytren’s cords. ² It can, however, also act upon collagen contained within flexor tendons, leading to tendon rupture. Methods can be employed to reduce the risk of inadvertent injection into flexor tendons. ³ This includes injecting at a level superficial to the flexors, with a knowledge that they are found on average 7 mm from the skin at metacarpophalangeal joints (MCPJ) level and 4 mm at interphalangeal joint (PIPJ) level. ⁴

We wish to highlight caution with the use of collagenase in a patient with upper limb spasticity. Recently in our institution, we treated an 84-year-old woman with flexion contractures affecting all digits of her left hand. These were progressive over 2 years. She had a background history of corticobasal syndrome, which affected her left upper limb in isolation, resulting in a so-called “alien limb” phenomenon. This is a phenomenon whereby the patient has involuntary movements in a limb in conjunction with a feeling of estrangement from the limb.

On examination, she had extreme flexion contracture of the index, middle, ring, and little fingers at MCPJ and PIPJ levels, with palpable cords to each digit, consistent with apparent Dupuytren’s disease. The flexion contractures were causing difficulty with hygiene, causing her nails to dig in to her palm and cause pain and ulceration. She also had a 1st webspace contracture, which seemed to be secondary to her left upper limb neurological disorder. This resulted in a “kissing” type ulcer on the radial border of her index finger, due to pressure from her thumb.

Initially, there was consideration given to using collagenase to release the discrete cords in her palm. However, as her contracted 1st web also needed treatment, a decision was made to proceed with an open segmental fasciectomy and 1st web space release under general anesthetic.

On exploration of the palm, it transpired that the discrete cords were due to bowstringing of the flexor tendons to a subcutaneous plane. An flexor digitorum profundus to flexor digitorum superficialis slide was performed instead at the level of the wrist, which provided full release of the digits, in conjunction with release of the 1st web space.

If we had proceeded with our initial plan to inject the palpable cords with collagenase, tendon rupture would have been the likely outcome. To our knowledge, there are no reports in the literature of a similar case. 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. This should also be kept in mind in the multiply operated hand where there may be scars resembling cords or where the tendons may also have bowstringed.