Boutonniere Deformity Treatment & Management

The basis of medical or nonoperative management is splinting. A variety of techniques have been described. They all require a minimum of 4 weeks (preferably 6 wk) of immobilization in extension to be effective.^[18]

A safety-pin splint (see image below) is the most efficient, lightest, and most practical splint available for digits with less than a 40° flexion contracture. It isolates the PIP joint in extension and allows for movement of the DIP joint. The splint is tightened progressively (static, progressive) in an effort to regain complete extension of the PIP joint.

Dynamic spring splints may be helpful for contractures greater than 40º. As the joint extension improves, the patient can switch to a safety-pin splint. The spring splints also can be helpful in the later stages of splinting because they allow the PIP joint to flex against resistance.

For severe established contractures, serial digital casts are extremely valuable initially. They typically are changed twice a week. Once the contracture improves, other splinting devices are used.

Long splints immobilizing the entire finger, hand, and distal forearm have been used. They are needlessly bulky.

In patients with rheumatoid arthritis and boutonniere thumb, an orthosis was found to effectively reduce pain, according to a study by Silva et al. Participants were evaluated at baseline and after 45 and 90 days. Patients in the intervention group experienced a statistically significant reduction in pain, and the thumb orthosis did not disrupt grip and pinch strength, function, Health Assessment Questionnaire score, or dexterity, according to the authors of the study.^[19]

A variety of surgical techniques are available for boutonniere deformity repair.^{[12, 20, 21]}

Patients should undergo a minimum of 1 month of splinting prior to surgical intervention for an established boutonniere deformity. Surgical results are highly dependent on the preoperative degree of joint contracture. Every effort should be made to achieve adequate extension prior to reconstruction of the extensor mechanism. The stiff joint must be corrected with therapy or surgery before tendon repair and/or reconstruction will be successful.

When the central slip is avulsed with a bone fragment, the fragment should be either fixed or excised, and the tendon reattached. The PIP then is held in extension with a Kirschner wire (K-wire) for a minimum of 10 days, followed by splinting.

In closed volar dislocations warranting surgery or in open injuries, open reduction and repair of all soft-tissue structures should occur, followed by stabilization of the PIP with a K-wire for at least 3 weeks. The PIP then is splinted for at least another 3 weeks while the DIP motion is encouraged.

A sample of the many described techniques is as follows:

• Stack has described use of the superficial flexor tendon to reconstruct the central slip and balance the forces across the PIP.^[22]
• Matev described using the lateral band on one side to reconstruct the central slip, while on the other side it is elongated to make use of a single lateral band.^[23]
• Salvi has repositioned the lateral bands dorsally.
• Littler and Eaton separate the extrinsic and interosseous tendon from the lumbrical and oblique retinacular ligaments and centralize the lateral bands.^[24]
• In chronic deformities, tenotomy of the extensor tendon distal to the triangular ligament has proven useful.

Rheumatoid arthritis

In stage I, splinting should be attempted first, but restoration then may be accomplished by synovectomy, lateral band relocation dorsal to the axis of rotation, or terminal tenotomy.^{[12, 13]}

In stage II, patients have the same options as in stage I but also may require central slip reconstruction.

Stage III varies from stage II in that the patient has joint destruction and a fixed flexion contracture. The 2 possible treatments now are limited to the salvage procedures of implant arthroplasty or arthrodesis. Arthrodesis is more predictable and more suited to higher demand hand function. Implant arthroplasty preserves motion, and, although full motion may not be gained, the arc of motion achieved often is more functional, especially for the ulnar digits.

All patients undergoing surgical repair need protection of the PIP after repair is complete. In most instances, fixation with a K-wire immobilizes the PIP for the immediate postoperative period, followed by some form of splinting. The length of time of K-wire fixation and splinting depends on the initial injury, the procedure performed, and the surgeon's preference. During the postoperative period, active DIP joint motion is encouraged.

Patients should be informed of the importance of maintaining the PIP in a proper splint for the designated amount of time following repair. Hand therapy is used, but patients usually can do well with proper instruction. The newer dynamic splints used toward the end of mobilization actually shorten the required splint time and appear to speed return of function.

Complications of boutonniere deformity are as follows^[9] :

• Infection in open injuries and operative management
• Loss of digital motion, especially flexion
• Loss of function in the hand
• Chronic pain, including reflex sympathetic dystrophy
• Repair and/or reconstruction failure necessitating additional treatment

Outcome and prognosis are good in acute injuries and in reconstruction of stage I and most stage II rheumatoid deformities. With stage III RA, extensive burns, irreversible contractures, and extensive soft-tissue losses, salvage procedures may be the only reasonable options. Rarely, contracture and pain result in amputation of the digit or ray.

From the number of surgical techniques available today, it is apparent that a universally agreed upon optimal technique does not exist for every clinical situation. Often, the surgeon's ability to reconstruct these deformities depends on soft tissues. Advances in tissue engineering may aid the surgeon's efforts in the future.

As medical therapy for RA and the other inflammatory arthritides improves, the incidence of these deformities should decrease.

For salvage situations, future improvements in metalloplastic joint implants may make this a more universally applicable option.