Boutonniere deformity is typically caused by an injury such as force to the top side of a flexed middle joint of a finger. The tear looks like a buttonhole (boutonniere in French). It can also be caused by a cut on the top of the finger, detaching the tendon from the bone. In some cases, arthritis can also lead to this injury.
Symptoms of boutonniere deformity include swelling and tenderness over the top of the finger’s middle joint. Signs of this condition can appear immediately following an injury or take up to three weeks to appear. In cases that are not treated quickly, the finger will rest in the characteristic bent position. In chronic deformity, the joint will become stiff and fixed in the bent position, even when using force.
Often confused as a “jammed finger,” those experiencing any symptoms should consult a physician. During the examination, you will be asked to straighten the affected finger. X-rays may also be used to identify any broken bones or injuries to the tendon.
Boutonniere deformity requires early treatment to retain full range and motion. Splints and hand therapy is often used. Surgery may be required for severe dislocations, lacerations, and chronic deformity.