It is a deformity of the fingers or toes in which the proximal interphalangeal joint is flexed and the distal interphalangeal joint is hyperextended.
If the central slip of the digital expansion is ruptured, minimal deformity results as long as the transverse ﬁbers of the expansion remain in tact. If they are also torn, a deformity is produced at the PIP joint.In this case, all extensor force will be transmitted to the distal phalanx by intact lateral bands, producing hyperextension of the DIP joint. The PIP joint buckles into ﬂexion and protrudes through the breech in the extensor hood. The two lateral bands will now run on the palmar aspect of the PIP joint and will exaggerate ﬂexion.
The deformity is the result of a rupture of the central tendinous slip of the extensor hood and is most common after trauma or in rheumatoid arthritis.
Signs and Symptoms
Signs of boutonnière deformity can develop immediately following an injury to the finger or may develop a week to 3 weeks later.
- The finger at the middle joint cannot be straightened and the fingertip cannot be bent.
- Swelling and pain occur and continue on the top of the middle joint of the finger.
Treatment options include prolonged splinting or surgery for patients who present for evaluation with a chronic injury.
Treatment for acute injury is uninterrupted splinting of the PIP in full extension for 6 weeks. After 6 weeks of immobilization, exercises are begun.The exercise involves two sequential maneuvers. The first is active assisted PIP joint extension. This will stretch the tight volar structures, will cause the lateral bands to ride dorsal to the PIP joint axis, and will put longitudinal tension on the lateral bands and oblique retinacular ligaments.The second maneuver is maximal active forced ﬂexion of the DIP joint while the PIP joint is held at 0°or as close to that position as the PIP will allow. This will gradually stretch the lateral bands and oblique retinacular ligaments to their physiologic length. Continue splinting 2 to 4 weeks when not exercising.When full PIP joint extension can be maintained throughout the day, then night splinting only is appropriate. Length of treatment and splinting may be several weeks.
While nonsurgical treatment of boutonnière deformity is preferred, surgery is an option in certain cases, such as when:
- The deformity results from rheumatoid arthritis.
- The tendon is severed.
- A large bone fragment is displaced from its normal position.
- The condition does not improve with splinting.
Surgery can reduce pain and improve functioning, but it may not be able to fully correct the condition and make the finger look normal. If the boutonniere deformity remains untreated for more than 3 weeks, it becomes much more difficult to treat.
- Darlene Hertling and Randolph M. Kessler,Management of common musculoskeletal disorders.4th ed,1983.
- David J Magee,Orthopedic Physical Assesment.1987.