Boutonnière deformity can occur as a result of a traumatic blow to the top of the finger or a cut that severs the tendon responsible for straightening the finger from the bone. Following the injury—immediately or up to three weeks later—the middle joint of the finger will not straighten and the fingertip will not bend. Swelling and pain will accompany the injury. Because Boutonnière deformity can result in permanent deformity and impaired functionality, immediate treatment is necessary. The longer a Boutonnière deformity goes without treatment, the harder it is to correct. In most cases, the non-surgical route is preferred. This may involve continual splinting for three to six months to straighten the finger and prevent the ends of the tendon from separating until it heals. Individuals may need to continue wearing the splint at night following the continual splinting period. Therapeutic exercises are often prescribed to stretch and strengthen the finger as it heals. Surgery may be necessary if the Boutonnière deformity occurs as a result of rheumatoid arthritis, the tendon is completely severed, a large bone fragment is out of place, or the condition does not improve with non-surgical treatment. While surgery will reduce pain and repair functionality, it may not be able to fully straighten the finger.