You are in: eMedicine Specialties > Orthopedic Surgery > HAND AND UPPER EXTREMITY Boutonniere DeformityArticle Last Updated: Jan 11, 2008AUTHOR AND EDITOR INFORMATIONSection 1 of 12
  Author: Randle L Likes, DO, Consulting Staff, Department of Emergency Medicine, Gateway Medical Center Randle L Likes is a member of the following medical societies: American College of Emergency Physicians and American Medical Association Coauthor(s): Sean D Ghidella, MD, Chief of Orthopedic Service, Consulting Surgeon, Department of Orthopedic Surgery, Madigan Army Medical Center Editors: Michael S Clarke, MD, Clinical Associate Professor, Department of Orthopedic Surgery, University of Missouri-Columbia School of Medicine; Francisco Talavera, PharmD, PhD, Senior Pharmacy Editor, eMedicine; Thomas R Hunt III, MD, John D Sherrill Professor of Surgery, Director, Division of Orthopedic Surgery, Surgeon in Chief, UAB Upper Extremity Fellowship, UAB Highlands Hospital, University of Alabama at Birmingham School of Medicine; Dinesh Patel, MD, FACS, Associate Clinical Professor of Orthopedic Surgery, Harvard Medical School; Chief of Arthroscopic Surgery, Department of Orthopedic Surgery, Massachusetts General Hospital; Harris Gellman, MD, Consulting Surgeon, Broward Hand Center, Voluntary Clinical Professor of Orthopedic Surgery and Plastic Surgery, Departments of Orthopedic Surgery and Surgery, University of Miami School of Medicine Author and Editor Disclosure Synonyms and related keywords: BD, buttonhole deformity INTRODUCTIONSection 2 of 12
  Boutonnière deformity (BD) can manifest acutely following trauma, but most BDs are found weeks following the injury or as the result of progressive arthritis. The proximal interphalangeal (PIP) joint of the finger is flexed, and the distal interphalangeal (DIP) joint is hyperextended (see Image 1). Treatment options depend partly on etiology of the deformity and are discussed in the sections to follow.1, 2, 3 ProblemA BD in the finger is due to deformity or disruption of the central slip, which is a key component of the extensor mechanism at the PIP joint. The flexion-extension mechanisms at the PIP joint are among the most complex in the hand. Weakening or disruption of the central slip with compromise of the triangular ligament subjects the lateral bands to migration volar to the axis of rotation of the PIP joint (see Images 2-3). The delicate balance between the extensor mechanism over the dorsal PIP joint and the flexors volarly is upset. As the deformity progresses, the now dominant flexor superficialis creates constant flexion at the PIP joint. Initially, the DIP joint exhibits an extensor lag.4 As the lumbrical and interosseous muscles (intrinsics) lose their insertion into the middle phalanx due to the incompetent central slip, their force of action is diverted entirely through the lateral bands. Over time, these lateral bands migrate palmarly and contract. This is accompanied by secondary shortening of the oblique retinacular ligaments. Together, these changes cause hyperextension at the DIP. BD of the thumb consists of a spectrum of instability patterns caused by imbalance between the extensor and flexor mechanisms. This complex problem is beyond the scope of this discussion. FrequencyThe frequency of occurrence depends on the etiology. A review of 43 of 71 patients treated in an emergency department with the diagnosis of jammed or sprained finger over a 14-month period revealed that 2 of the 43 patients went on to develop a BD. Up to 50% of patients with rheumatoid arthritis (RA) are estimated to develop a BD in at least 1 digit.5 EtiologyThe 3 main etiologies described are mechanical trauma, RA and other inflammatory arthritides, and burns and infections. PathophysiologyThe pathophysiology varies depending on the etiology. Trauma Several mechanisms of trauma can lead to a BD. A laceration over the joint may involve the central slip. Axial loading or forced flexion with the PIP in extension can cause closed disruption of the central slip. Volar dislocation of the PIP can cause avulsion of the central slip as well. Finally, any combination of the above may be responsible for a BD.6, 7, 8, 9 Rheumatoid arthritis The mechanism in RA is quite different from that associated with trauma. The PIP is slowly forced into flexion by chronic synovitis of the joint, elongating the central slip and ultimately leading to rupture. Subsequent volar displacement of the lateral bands below the axis of the PIP rotation creates increased tension on the DIP extensor mechanism, leading to hyperextension and limited flexion of the DIP.10, 11 Burns Full-thickness burns may disrupt the central slip, but most commonly, BD occurs from secondary infection. Rarely, increased pressure over the PIP from the rigid eschar may cause ischemic necrosis of the central slip.12 ClinicalThe history varies depending on the primary etiology of the deformity. Even though most patients who present with a tender, swollen, and stiff PIP joint have sustained a recent closed injury (usually an axial load), they all should be questioned as follows:
Trauma The digit is held in a semiflexed position, and active motion, especially PIP joint extension and DIP joint flexion, is decreased. Except in late presentations, full extension can be achieved passively. Patients with jammed fingers do not develop classic BD until 2-3 weeks following the initial injury. Typically, the initial central slip disruption is either misdiagnosed or undertreated on first presentation. Common splinting techniques with the PIP joint partially flexed serve to accentuate the deformity.6, 7, 8, 9 In lacerations of the central slip, acute presentations of BD can occur. The digit is held slightly flexed at the PIP joint, with full extension passively. With attempted active extension of the digit, the PIP joint flexes, and the DIP joint hyperextends due to mechanisms described above. Volar PIP dislocations commonly disrupt the central slip insertion. However, when the patient presents, the joint already may be reduced. With volar dislocations and any jammed finger, the examiner must maintain a high index of suspicion for a central slip injury to avoid development of a BD. Dorsal avulsion fractures or any fractures involving the base of the middle phalanx are at high risk for developing a BD. Open or closed fractures appear to have the same incidence of subsequent BD formation. Rheumatoid arthritis BD in patients with RA can be classified into 1 of the following 3 stages, which serve as a guide to the appropriate management:
Pseudoboutonnière deformity is a condition marked by PIP joint flexion contracture and restricted flexion of the DIP joint. The characteristic hyperextension of the DIP in BD is not present. It often is the result of a hyperextension injury causing inflammation and contracture of the checkrein ligaments, the oblique retinacular ligaments, and, possibly, the first cruciate pulley. Pseudoboutonnière deformity must be distinguished from BD because pathophysiology and treatment are different. INDICATIONSSection 3 of 12
Most patients receive conservative treatment by splinting initially (see Medical therapy). The indications for surgical intervention initially include open injuries, unreducible volar dislocation of the PIP joint, and displaced avulsion fractures of the dorsal base of the middle phalanx. Once a BD is established, surgery may be required if splinting techniques fail. In patients with RA, only stage I disease can be treated with splinting techniques. Once stage II develops, surgical intervention is necessary (see Surgical therapy). RELEVANT ANATOMYSection 4 of 12
The relevant anatomy involved is discussed above. Please see the diagram in Image 4 for orientation and clarification. CONTRAINDICATIONSSection 5 of 12
Remember that BD is a functional deformity. Attempts at surgical reconstruction risk flexion of the joint and can render the joint less functional. For that reason, the patient and physician must carefully weigh and measure the risks and benefits prior to embarking on surgical planning. A relative contraindication to surgical reconstruction of the central slip is failure to achieve acceptable range of motion in the PIP passively. WORKUPSection 6 of 12
Lab Studies
Imaging Studies
Other Tests
TREATMENTSection 7 of 12
Medical therapyThe 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.13
Surgical therapyA variety of surgical techniques are available for BD repair.10, 14, 15 Preoperative detailsPatients should undergo a minimum of 1 month of splinting prior to surgical intervention for an established BD. 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. Intraoperative detailsWhen 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:
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.10, 11 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. Postoperative detailsAll 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. Follow-upPatients 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. COMPLICATIONSSection 8 of 12
Complications of BD are as follows7:
OUTCOME AND PROGNOSISSection 9 of 12
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. FUTURE AND CONTROVERSIESSection 10 of 12
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. MULTIMEDIASection 11 of 12
REFERENCESSection 12 of 12
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