Operative Correction of Swan-Neck and Boutonniere Deformities in the Rheumatoid Hand

Martin I. Boyer, MD, MSc, FRCSC, and Richard H. Gelberman, MD

Abstract

A swan-neck or occurs in approximately half of patients to evaluate for atlantoaxial subluxa- with rheumatoid . The cause of boutonniere deformity is chronic syno- tion, basilar impression, and subaxial vitis of the proximal interphalangeal joint. Swan-neck deformity may be caused instability. Previous radiographs, if by synovitis of the metacarpophalangeal, proximal interphalangeal, or distal available, are compared with current interphalangeal joints. Numerous procedures are available for the operative films for signs of progressive instabil- correction of these deformities. The choice of surgical procedure is depen- ity. If the tip of the dens cannot be dent on accurate staging of the deformity, which is based on the flexibility of the adequately visualized on plain lateral proximal interphalangeal joint and the state of the articular cartilage. The radiographs of the cervical spine or patientÕs overall medical status and corticosteroid use, the condition of the cer- base of the skull, magnetic resonance vical spine, the need for operative treatment of large joints, and the presence of imaging of the cervical spine is indi- deformities of the wrist and metacarpophalangeal joints must also be considered cated. when planning treatment. In the later stages of both deformities, soft-tissue Regional anesthesia, such as axil- procedures alone may not result in lasting operative correction. lary block, is preferable to general J Am Acad Orthop Surg 1999;7:92-100 anesthesia for correction of finger deformities because postoperative pain control is better and systemic side effects are fewer. General Finger deformities are common in nation of deformity.3 Within the anesthesia is required if concurrent persons with , broader context of a patientÕs med- procedures are to be performed, which affects 3.2% of Americans ical status, the condition of the cer- such as the harvest of an iliac-crest between the ages of 18 and 79 vical spine and the larger joints of bone graft. However, the presence years.1 The incidence of uncor- the upper and lower extremities and of instability of the cervical spine on rectable swan-neck and bouton- the presence of coexistent deformi- preoperative evaluation may influ- niere deformities is estimated to be ties of the wrist and hand must be ence selection of the type of general between 8% and 16% during the considered in the timing and selec- anesthetic utilized. first 2 years after the onset of sys- tion of operative procedures. temic disease, and the prevalence of finger deformities in patients with established rheumatoid arthritis is Preoperative Assessment Dr. Boyer is Assistant Professor, Department of approximately 14% for swan-neck of the Cervical Spine and Orthopaedic Surgery, Washington University School of Medicine, St Louis. Dr. Gelberman is deformities and 36% for bouton- Other Joints Reynolds Professor and Chairman, Department niere deformities.2 Often the most of Orthopaedic Surgery, Washington Univer- visible manifestations of rheuma- The cervical spine, which is common- sity School of Medicine. toid arthritis, such deformities can ly affected in patients with rheuma- be painful and can impair finger toid arthritis, should be evaluated in Reprint requests: Dr. Boyer, Department of and hand function significantly. all patients considered for hand Orthopaedic Surgery, Washington University School of Medicine, Suite 11300, 1 Barnes Principles guiding the operative surgery. The evaluation focuses on Hospital Plaza, St Louis, MO 63110. correction of deformities in the radiographic changes, neurologic hands of patients with rheumatoid signs and symptoms, and neck pain. Copyright 1999 by the American Academy of arthritis focus on relief of pain, Anteroposterior, lateral, and flexion- Orthopaedic Surgeons. improvement of function, and elimi- extension lateral views are obtained

92 Journal of the American Academy of Orthopaedic Surgeons Martin I. Boyer, MD, MSc, FRCSC, and Richard H. Gelberman, MD

The , , , and ulnae syndrome), and rupture of the Flexor is indicated joints are commonly involved extensor pollicis longus is essential. by palpable mobile fullness in the in rheumatoid arthritis. The effect Evaluation of the MCP joints for distal volar forearm. Flexor teno- of arthritis on large joints influences active synovitis and the presence of synovitis of the finger is identified on the ability of a patient to care for ulnar drift and volar subluxation is the basis of three findings: swelling, himself or herself, to carry out activ- also critical. Wrist, DRUJ, and MCP discrepancy between active and pas- ities of daily living, and to partici- joint abnormalities are important not sive motion of the finger, and palpa- pate in postoperative hand rehabili- only because they may be of greater ble crepitus along the course of the tation and therefore may necessitate functional significance to the patient flexor tendon on active and passive operative correction of large-joint than the finger deformities, but also flexion of the digit. Extensor teno- arthritis before operative correction because they may directly contribute synovitis is signaled by the presence of finger deformities. For instance, to the development of those defor- of persistent swelling and crepitus the hand and wrist must be able to mities by altering the extent and along the course of the long extensor withstand the added upper-extremity direction of in vivo forces generated tendons both proximal and distal to forces required to use walking aids by flexor and extensor muscle con- the extensor retinaculum. during rehabilitation of the lower traction in the . In addition, Flexor or extensor tendon teno- extremity. Stabilization of the wrist wrist and MCP joint deformities synovitis or rupture at the wrist or thumb metacarpophalangeal may influence the longevity of cor- level must be identified, as correc- (MCP) or interphalangeal joints by rections of finger deformities. tion of the finger deformity without arthrodesis facilitates the patientÕs concomitant operative correction of rehabilitation after hip or knee wrist synovitis and tendon rupture arthroplasty by allowing pain-free Basic Assessment of Finger does not increase active range of use of walking supports, such as Deformities motion. Proximal tendon ruptures walkers, crutches, and canes. are diagnosed by visual inspection Oral corticosteroid administra- Once the physical examination of (i.e., if proximal muscle contraction tion presents special concerns, the large joints, wrist, and hand has is seen without finger motion) or including the risk of postoperative been completed, clinical examina- palpation (i.e., if tendon excursion wound infection and an increase in tion of the fingers is carried out. is absent distal to the site of a rup- overall healing time of soft tissues. The resting positions of the proxi- ture). The tenodesis effect of wrist If a general anesthetic is required mal interphalangeal (PIP) and dis- flexion and extension on digital for a patient taking oral cortico- tal interphalangeal (DIP) joints are motion is assessed to rule out ten- steroid medication, the preopera- noted, and the active and passive don ruptures at the wrist level. If tive administration of intravenous ranges of motion of each joint are passive wrist flexion fails to elicit corticosteroids is indicated, fol- recorded. The initiation of flexion extension of the fingers, rupture of lowed by a tapering-dose regimen is observed while examining the the long extensor tendons should postoperatively. active ranges of motion, because be suspected. Adhesion of a rup- difficulty in initiating PIP joint flex- tured tendon to the surrounding ion is associated with early swan- tissue proximal to the wrist may Clinical Evaluation of the neck deformity. decrease the accuracy of this test. Wrist and Hand Involvement of the PIP and DIP The Bunnell test of intrinsic ten- joints in the rheumatoid process is don tightness is performed in all fin- Because collapse of the carpus into assessed. Bulging of the joint indi- gers of patients with rheumatoid supination, volar translation, and cates the presence of an effusion and arthritis. It has special relevance in ulnar translocation occurs often and implies possible capsular attenua- patients with early swan-neck defor- is most easily noted on visual tion and laxity. Crepitus with joint mities, as it assesses the relative con- inspection, examination for active motion indicates articular cartilage tribution of tight intrinsics to the synovitis and deformity of the radio- damage. In cases of boutonniere genesis of the deformity. While the carpal joints and the distal radioul- deformity, the skin is assessed for MCP joint is held in the extended nar joints (DRUJs) should be carried tightness volarly over the PIP joint position, the degree of resistance to out routinely. Inspection for dorsal and attenuation over the dorsum of passive flexion of the PIP joint is subluxation of the distal ulna, rup- the PIP joint. In cases of swan-neck determined (Fig. 1, A). Increased ture of the extensor carpi ulnaris ten- deformity, the skin is examined for resistance to passive PIP joint flexion don and the extensor tendons of the tightness over the PIP joint dorsally signifies relative shortening of the small and ring fingers (the caput and volar skin attenuation. intrinsic muscle-tendon unit.

Vol 7, No 2, March/April 1999 93 Swan-Neck and Boutonniere Deformities in the Rheumatoid Hand

A B

Fig. 1 A, Test for intrinsic tightness. While the MCP joint is held in the extended position, the degree of resistance to passive flexion of the PIP joint is determined. Increased resistance to passive PIP joint flexion signifies relative shortening of the intrinsic muscle-tendon unit. B, Test for tightness of the oblique retinacular ligament. The PIP joint is held in maximum extension by the examiner, and the degree of resistance to passive flexion of the DIP joint is evaluated.

Tightness of the oblique retinac- accentuated by intrinsic muscle well as altered joint-contact mech- ular ligament in digits with early and intrinsic tightness anics, contributes to a fixed and oc- boutonniere deformity is also eval- due to MCP joint flexion and volar casionally painful deformity. uated with another type of intrinsic subluxation. Synovitis in the DIP Nalebuff4 and Zancolli5 have tightness test. The PIP joint is held joint with attenuation or rupture of each devised comprehensive classi- in maximum extension by the the terminal tendon of the extensor fication schemes for swan-neck de- examiner, and the degree of resis- mechanism concentrates the exten- formity. The classification devised tance to passive flexion of the DIP sor forces at the PIP joint, which by Nalebuff is very helpful in select- joint is evaluated (Fig. 1, B). can initiate or accentuate a swan- ing a treatment option for operative neck deformity. Synovitis in the correction of the deformity. Zan- PIP joint causes attenuation of the colliÕs classification is instructive in Etiology and Classification volar plate, which acts as a check- determining the underlying cause of of Swan-Neck Deformity rein to PIP joint hyperextension. the deformity. Synovitis also produces attenua- Nalebuff described four types. Swan-neck deformity is character- tion of the transverse retinacular lig- Type I is characterized by a flexible ized by hyperextension at the PIP aments, which are responsible for hyperextension deformity of the joint and flexion of the DIP joint maintaining the normal position of PIP joint. In type II deformity, (Fig. 2). The deformity, which may the lateral bands. When the trans- tightness of the intrinsic muscles be flexible or fixed, is associated verse retinacular ligaments become causes limitation of PIP joint flexion with varying degrees of destruc- attenuated, the lateral bands can when the MCP joint is maintained tion of the PIP joint. subluxate dorsal to the axis of PIP in extension. Type III deformity is Synovitis of the PIP joint with a joint rotation and produce a con- characterized by limited PIP joint variable degree of tenosynovitis stant and accentuated PIP joint flexion in all MCP joint positions within the finger flexor sheath is extension force. Eventually, the due to the inability of the lateral the most common cause of swan- extensor mechanism over the PIP bands to translate volar to the axis neck deformity. Attenuation of the joint, especially the triangular liga- of rotation of the PIP joint. In type volar plate, collateral ligaments, ment, and the dorsal skin become IV deformity, there is destruction of and flexor digitorum superficialis contracted, resulting in a fixed the articular surface of the PIP joint. insertion allows the PIP joint to hyperextension of the ZancolliÕs classification scheme hyperextend due to extensor mech- joint. Articular destruction sec- focuses on three potential causes of anism forces. These forces are ondary to persistent synovitis, as deformity. The first involves rela-

94 Journal of the American Academy of Orthopaedic Surgeons Martin I. Boyer, MD, MSc, FRCSC, and Richard H. Gelberman, MD tive shortening of the long digital improve the arc of PIP joint flexion. , fusion of the DIP extensor tendons secondary to MCP In its early stages, when a cor- joint is an option. Arthrodesis of joint subluxation or dislocation, rectable swan-neck deformity is the DIP joint can be performed wrist flexion deformity, or primary associated with minimal synovitis of with a low-profile cannulated mallet-finger deformity, which causes the PIP joint, nonoperative treat- screw or other headless screw for extrinsic extensor tightness, an in- ment with the use of external splints, secure fixation.6 A headless screw creased extension moment at the such as a figure-of-eight ring splint, can be buried beneath the osseous PIP joint, and PIP joint hyperexten- is advocated to prevent PIP joint surface of the tip of the distal pha- sion. The second involves relative hyperextension. This technique is lanx, which helps to avoid irrita- shortening of the digital intrinsic appropriate if inability to initiate PIP tion of the fingertip on fine object muscles (intrinsic tightness) sec- joint flexion from the position of grasping. Alternatively, Kirschner- ondary to MCP joint subluxation or hyperextension is the difficulty or if wire fixation, with or without the dislocation, which results in translo- the deformity is not disabling. addition of a tension-band wire, or cation of the lateral bands dorsal to An extensor tendon subluxation lag-screw fixation with a 2.0- or 2.4- the axis of rotation of the PIP joint at the level of the MCP joint or a mm-diameter screw may be used. and the development of a hyperex- flexion contracture of the MCP joint The DIP joint is approached dor- tension deformity. The third cause should be corrected concurrent with sally through an incision centered involves weakening and attenuation or prior to surgical correction of the over the joint. The germinal matrix of the volar plate and collateral liga- swan-neck deformity. A wrist flex- of the nail proximal to the eponych- ments of the PIP joint and destruc- ion contracture may also contribute ium must be avoided. If headless- tion of the articular cartilage, which to the swan-neck deformity, and its screw fixation is chosen, the articu- leads to the development of a swan- correction may be required to bal- lar cartilage is excised with a neck deformity of the PIP joint. ance the hand. rongeur, and the medullary cavi- The primary cause of the flexible ties of the middle and distal pha- swan-neck deformity must be langes are manually drilled. After Treatment of Swan-Neck established before initiating opera- the size of the screw has been de- Deformity tive treatment. Although PIP joint termined, a transarticular headless synovitis and weakening of the screw is inserted under fluoroscop- The treatment of swan-neck defor- volar PIP structures are the most ic guidance through a stab wound mities begins with simple methods common findings, DIP joint synovi- in the tip of the finger 1 to 2 mm for the early stages (as classified tis can also be a primary cause of volar to the nail plate with the joint according to Nalebuff) and pro- swan-neck deformity, due to the in full extension (Fig. 3). A lag ef- ceeds to more complex procedures. transfer and concentration of exten- fect is achieved across the arthrod- sion forces at the PIP joint. esis site. A mallet-finger splint is Type I worn until fusion is noted radio- The goals of treatment of the flex- DIP Fusion graphically. The PIP joint is not ible swan-neck deformity are to pre- If full PIP joint flexibility is pre- immobilized, and the patient is vent PIP joint hyperextension and to served in a primary rheumatoid encouraged to actively flex and

A D C

B E

Fig. 2 Swan-neck deformity. Left, Terminal tendon rupture may be associated with synovitis of the DIP joint, leading to DIP joint flexion and subsequent PIP joint hyperextension (A). Rupture of the flexor digitorum superficialis tendon may occur due to infiltrative synovitis, which may lead to decreased volar support of the PIP joint and subsequent hyperextension deformity (B). Right, Lateral-band subluxation dorsal to the axis of rotation of the PIP joint (C), contraction of the triangular ligament (D), and attenuation of the transverse retinacular liga- ment (E) are depicted.

Vol 7, No 2, March/April 1999 95 Swan-Neck and Boutonniere Deformities in the Rheumatoid Hand

The sheath is opened at the proxi- mal edge of the A4 pulley. With the finger in the flexed position, the slip of the flexor digitorum superfi- cialis tendon is extracted and sec- tioned proximally at the level of the decussation. The slip is then su- tured to the outside of the flexor sheath along its volar-midlateral aspect. The postoperative protocol is similar to that previously de- scribed. Fig. 3 Fusion of the DIP joint with use of a Herbert-Whipple screw. Lateral-Band Tenodesis Rerouting of the lateral band volar to the axis of rotation of the extend the PIP joint during the joint in 20 degrees of flexion elimi- PIP joint, as described by Littler postoperative period. nates locking and ensures that the (volar to ClelandÕs ligament) or If a box-wire technique is pre- initiation of digital flexion at the Zancolli5 (through the flexor tendon ferred, 26- or 28-gauge cerclage PIP joint is improved and that the sheath), may be used to treat the wires are passed through the distal arc of PIP joint motion remains early flexible swan-neck deformity aspect of the middle phalanx and functional. caused by PIP joint synovitis. The the proximal aspect of the distal Our preferred operative ap- effect is similar to that achieved phalanx. One wire is oriented in proach is a Bruner incision extend- with tenodesis of the flexor digito- the frontal plane; the second, in the ing from the proximal digital rum superficialis, in that a volar sagittal plane. The wires are tight- crease to the distal digital crease. A checkrein against PIP joint hyperex- ened simultaneously, and fixation triangular skin flap is raised to tension is provided. The choice may be augmented by a transartic- identify the digital sheath, and the between lateral-band tenodesis and ular Kirschner wire to control neurovascular bundles are protect- flexor tenodesis is a matter of per- translation. Some surgeons prefer ed. The flexor sheath from the dis- sonal preference. transarticular pinning of the DIP tal end of the A2 pulley to the With this technique, the exten- joint with two Kirschner wires as proximal end of the A4 pulley is sor tendon apparatus overlying the the sole method of fixation, in identified and opened as a flap PIP joint is approached dorsally order to control both translation with the base along the bone at- through a longitudinal curvilinear and rotation. tachment of the flexor sheath. The incision. Dissection is carried flexor digitorum superficialis ten- volarly, and ClelandÕs ligament is PIP-Joint Flexor Tenodesis don is identified within the digital divided to expose the flexor Often, the major difficulty noted sheath, and one slip of the tendon sheath. The neurovascular bundle by the patient with a flexible swan- is sectioned proximally at the level is protected, and the dorsally sub- neck deformity is an inability to of the decussation. The sectioned luxated lateral band is dissected initiate active PIP joint flexion due tendon end is passed through a free of its dorsal attachments to the to a hyperextended resting posture. transverse incision in the distal central extensor tendon and the The loss of volar support at the PIP aspect of the A2 pulley and sutured proximal aspect of the triangular joint is addressed by means of a back on itself. Immobilization with ligament. The lateral band is car- flexor tenodesis.7 Oblique retinac- a dorsal block splint in 20 degrees ried volar to the axis of rotation of ular ligament reconstruction or of PIP joint flexion is maintained the PIP joint with passive flexion volar-skin dermodesis are both op- for 6 weeks. Passive and active of the PIP joint. It is not detached tions. Alternatively, flexor tenode- PIP- and DIP-joint flexion exercises from either its proximal or its dis- sis can reliably establish a sturdy are begun at 3 weeks. tal attachments. checkrein against PIP joint hyper- A less extensive approach may A wide dorsally based flap of extension that does not attenuate be undertaken as well (Brian D. flexor sheath is created at the level over time. While not necessarily Adams, MD, written communica- of the PIP joint. The incision in the improving the total arc of flexion of tion, November 1998). A midlateral sheath is made under direct vision the PIP joint, tenodesis of the PIP incision is made over the PIP joint. close to the midline of the digit.

96 Journal of the American Academy of Orthopaedic Surgeons Martin I. Boyer, MD, MSc, FRCSC, and Richard H. Gelberman, MD

The volarly displaced lateral band Type III joint rotation with passive flexion; is placed under the raised flap of Type III MCP swan-neck defor- therefore, fixation of the lateral flexor tendon sheath. The flap is mity is characterized by decreased bands volar to the axis of rotation replaced in its anatomic position PIP joint flexion in all positions of of the PIP joint is not required. and then repaired with nonab- MCP joint flexion and extension. Palmar traction lysis of the flex- sorbable sutures. This type of swan-neck deformity or tendons is carried out in addi- Free gliding of the lateral band cannot be addressed solely by any tion to the dorsal releases if flexor is confirmed by gentle proximally one of the procedures described tendon tenosynovitis is present. and distally directed traction on the previously. The lateral bands have This is done through an incision translocated lateral band. The joint become fixed dorsal to the axis of over the distal volar forearm. The is maintained in flexion by an assis- rotation of the PIP joint, and a PIP- desired tendon is isolated and tant during closure, and the dress- joint soft-tissue contracture is pres- pulled in a proximal direction to ing is applied. A dorsal blocking ent. The authors prefer a technique lyse any restricting adhesions prox- splint is used to prevent PIP joint that includes release of the lateral imal to the finger. Transarticular extension beyond 30 degrees of bands from their dorsal attach- PIP pinning with the joint flexed to flexion for 4 weeks. Digital flexion ments to the central tendon and to 20 degrees is maintained for 2 is encouraged in the postoperative the triangular ligament, with sub- weeks postoperatively for severe period, but full active PIP joint sequent translocation of the lateral deformities. extension is not allowed until 6 bands volar to the axis of rotation weeks postoperatively. of the PIP joint. This is combined Type IV with a dorsal PIP joint capsulecto- In type IV swan-neck deformity, Type II my, collateral ligament release, and there is a fixed hyperextension In type II swan-neck deformity, tenolysis of the extensor tendon deformity of the PIP joint with passive and active flexion of the over the dorsum of the proximal advanced destruction of the articu- PIP joint are limited when the MCP phalanx.8,9 lar cartilage of the PIP joint. Soft- joint is in extension due to tight- An oblique incision over the tissue procedures alone neither ness of the intrinsic muscles. dorsum of the middle phalanx is relieve pain reliably nor restore Arthritis in the MCP joint is fre- continued as a curvilinear longitu- digital motion and function. Ar- quently associated with intrinsic dinal dorsal incision over the PIP throdesis or flexible implant arth- muscle tightness. Thus, to obtain joint. Skin flaps are raised to ex- roplasty are reliable options when and maintain correction of a swan- pose the dorsally subluxated lateral joint destruction has occurred. neck deformity, MCP joint arthro- bands, the central extensor tendon plasty with or without intrinsic over the dorsum of the proximal Arthrodesis release may be required. phalanx, and the lateral aspect of Arthrodesis of the PIP joint in a In the absence of deforming the PIP joint. Both lateral bands position of flexion is the authorsÕ MCP joint arthritis, isolated intrin- are then released along their dorsal preferred technique for type IV sic release may be indicated. The margins throughout the length of deformities.10 Fusion of the PIP intrinsic tendon, which inserts into the incision from over the middle joint provides relief of pain and the lateral band at the level of the of the proximal phalanx to their allows digits to readily conform base of the proximal phalanx, is confluence over the dorsum of the when medium- and large-size ob- approached through a dorsal inci- middle phalanx. The central exten- jects are grasped. The PIP joint is sion centered over the MCP joint sor tendon is dissected free of the approached through a dorsal curvi- and the proximal phalanx. The underlying dorsum of the proximal linear incision, and the central slip central extensor tendon, ulnar phalanx as well as the dorsal PIP is detached from the base of the sagittal band, and ulnar intrinsic joint capsule. middle phalanx. Sufficient collater- tendons are exposed. The lateral The dorsal PIP joint capsule is al ligament is resected to allow band is isolated, and a 1-cm seg- then resected, and the radial and delivery of the head of the proxi- ment of lateral band with attached ulnar collateral ligaments are mal phalanx and the base of the sagittal band fibers is excised.4 released from the proximal phalanx middle phalanx into the wound. Release of the ulnar intrinsic ten- beginning dorsally. Sufficient col- The remaining articular surfaces don may diminish ulnar drift at the lateral ligament release is carried and subchondral bone are resected MCP joint and may correct the out to passively flex the joint to 90 with use of a rongeur, and the bone deforming forces that cause swan- degrees. The lateral bands will ends are apposed in 30 degrees of neck deformity. come to lie volar to the axis of PIP flexion.

Vol 7, No 2, March/April 1999 97 Swan-Neck and Boutonniere Deformities in the Rheumatoid Hand

A tension band over two Kirsch- begun at the time of suture re- ture of the PIP joint and a hyperex- ner wires provides adequate fixa- moval. tension posture of the DIP joint.11 tion for the PIP joint fusion. A The deformity may be flexible or transverse hole is drilled through PIP Arthroplasty With a Silicone fixed. Unlike the swan-neck defor- the dorsal aspect of the middle por- Implant mity, which may be caused by tion of the diaphysis of the middle A volar approach is made through abnormalities at the MCP, PIP, and phalanx. A 26-gauge flexible wire a Bruner incision centered over the (occasionally) DIP joints, the incit- is passed through. Two 0.035-inch PIP joint flexion crease. The digital ing event is persistent synovitis of Kirschner wires are drilled oblique- neurovascular bundles are retracted, the PIP joint, which causes attenua- ly in a retrograde fashion through and the flexor sheath is opened from tion of the central slip, transverse the distal end of the proximal pha- immediately distal to the A2 pulley retinacular ligaments, and triangu- lanx and then antegrade into the to immediately proximal to the A4 lar ligament. Due to weakening of middle phalanx with the PIP joint pulley. The flexor digitorum super- these structures, the lateral bands held in 25 to 40 degrees of flexion ficialis and profundus tendons are subluxate volar to the axis of rota- (index finger at 25 degrees, increas- retracted, and the volar plate is tion of the PIP joint and become ing at 5-degree increments for the released from its insertion into the PIP joint flexors rather than exten- long, ring, and small fingers). The proximal phalanx. The joint sur- sors. With persistence of PIP joint wires are inserted into the medul- faces are resected, taking care to pre- flexion, the volar plate, collateral lary cavity of the middle phalanx, serve the attachments of the collater- ligaments, and oblique retinacular parallel to each other in both the al ligaments and the central slip, and ligaments become contracted, lead- frontal and the sagittal plane. The the medullary cavities are prepared ing to a fixed contracture of the flexible wire is bent in a figure-of- (with the use of curettes, rasps, or a joint. eight fashion and then passed burr) to accept the prosthesis. Both Nalebuff and Zancolli have around the proximal Kirschner Sufficient bone is removed to pre- described classification schemes wires. The wire is then tightened vent the prosthesis from assuming a that characterize the deformity and in a single knot. hyperextended position, and the guide treatment. NalebuffÕs sys- Intraoperative fluoroscopy is flexor sheath is closed. Protected tem has three stages, based on the used to confirm proper positioning range-of-motion exercises com- passive correctability of the PIP of the arthrodesis and the internal mence on suture removal. joint flexion deformity and the con- fixation. The Kirschner wires are dition of the articular surfaces of cut, the extensor mechanism is the PIP joint.12 Stage 1 boutonniere repaired, and the skin is closed. An Etiology and Classification deformity is characterized by syno- external splint is applied to the PIP of Boutonniere Deformity vitis of the PIP joint and a slight, joint and is worn until the fusion is fully correctable extensor lag. solid. Active- and passive-motion The boutonniere deformity (Fig. 4) Stage 2 deformity consists of a rehabilitation of the DIP joint is is characterized by a flexion pos- marked flexion deformity of the

B A

C D

Fig. 4 Boutonniere deformity. Left, Primary synovitis of the PIP joint (A) may lead to attenuation of the overlying central slip (B) and dorsal capsule and increased flexion at the PIP joint. Lateral-band subluxation volar to the axis of rotation of the PIP joint (C) may lead in time to hyperextension. Contraction of the oblique retinacular ligament (D), which originates from the flexor sheath and inserts into the dorsal base of the distal phalanx, may lead to extension contracture of the DIP joint. Right, Clinical photograph illustrates flexion posture of the PIP joint and hyperextension posture of the DIP joint in boutonniere deformity.

98 Journal of the American Academy of Orthopaedic Surgeons Martin I. Boyer, MD, MSc, FRCSC, and Richard H. Gelberman, MD

PIP joint that is either flexible or extensor tendon is exposed and fixed. Stage 3 deformity is charac- sharply divided over the distal terized by destruction of the PIP aspect of the middle phalanx at a joint. level that is proximal to the inser- Zancolli5 distinguished bouton- tion of the fibers of the oblique reti- niere deformity due to rheumatoid nacular ligament. Although a arthritis from traumatic bouton- slight mallet deformity may occur, niere deformity. In his system, the deformity is well tolerated, as there are two types of boutonniere the new position improves the deformities: those with passively patientÕs ability to grasp. correctable PIP joint flexion and DIP joint extension deformities and Central-Slip Reconstruction those with fixed deformities. As For more severe boutonniere deformities progress from flexible deformities in which there is a well- to fixed, they become far less likely preserved PIP joint cartilage (Nale- Fig. 5 Exposure of the PIP joint with a to respond to splinting or soft-tissue buff stage 2 deformities), central- dorsal incision reveals synovitis of the joint with attenuation of the central slip and reconstructions. slip reconstruction by means of an volar subluxation of the lateral bands. anatomic technique, as advocated by Urbaniak14 and Flatt,15 is indi- Treatment of Boutonniere cated. A curvilinear incision is Deformity made over the dorsum of the PIP with release of the terminal exten- joint, and the central slip and later- sor tendon is a less reliable option, Early boutonniere deformity may al bands are identified. The redun- due to marked attenuation of the be treated nonoperatively with dant portion of the central slip over dorsal extensor mechanism. low-profile extension splinting of the PIP joint is excised, and the ten- the PIP joint. A mild boutonniere don is advanced and reattached to deformity does not usually cause the base of the middle phalanx. Results functional impairment, because it The lateral bands are mobilized does not limit grasp of moderate- from their volarly displaced posi- There is a relative lack of clinical and large-size objects. Synovec- tion by releasing the transverse studies evaluating the results of tomy of the PIP joint may be indi- retinacular ligament attachments operative treatment of swan-neck cated in a patient with a mild, pro- along the volar margin of the later- and boutonniere deformities in gressive boutonniere deformity al bands. The lateral bands are patients with rheumatoid arthritis. and persistent synovitis that is repositioned dorsally over the PIP In addition, the number of surgical unresponsive to oral medication or joint and sutured to each other. A options for the correction of rheu- local injection of corticosteroids terminal tenotomy, as previously matoid finger deformities is rela- (Fig. 5). described, is done not only to cor- tively limited. In a report on the Hyperextension of the DIP joint rect a preexisting DIP-joint hyper- results of operative treatment of causes functional limitation when it extension deformity, but also to Nalebuff type III swan-neck and prevents the volar aspect of the fin- prevent a secondary deformity due stage 2 boutonniere deformities, gertip from coming into contact to the force from the repositioned Kiefhaber and Strickland9 conclud- with an object on digital flexion. bands. ed that the results of soft-tissue Operative correction of a DIP-joint procedures for swan-neck deformi- hyperextension deformity, a straight- Arthrodesis ty are more consistent than those forward solution to this problem, is If articular destruction is evident for boutonniere deformity. The ini- most easily accomplished by sec- or if a severe fixed flexion contrac- tial postoperative gain in arc of tion of the terminal tendon over the ture is present, even without severe flexion after lateral band release, middle phalanx.13 articular changes, arthrodesis of extensor tenolysis, and PIP-joint the PIP joint in 25 to 40 degrees of dorsal capsulectomy for type III Terminal Tendon Release flexion, as described for a swan- swan-neck deformity decreased by Release of the terminal tendon13 neck deformity, is a reliable option 17 degrees during the first year is carried out through a longitudi- for managing pain and treating postoperatively. Recurrence of nal incision over the middle pha- deformity. Flexible implant arthro- deformity was noted, signifying lanx and DIP joint. The terminal plasty of the PIP joint combined the transient nature of correction of

Vol 7, No 2, March/April 1999 99 Swan-Neck and Boutonniere Deformities in the Rheumatoid Hand the PIP-joint hyperextension defor- Tonkin et al published two re- that reported by Kiefhaber and mity in some fingers. Despite dete- views of patients treated for swan- Strickland9 for digits without joint rioration in results over time, the neck deformity due to various destruction. total arc of PIP joint motion was causes and in various stages.16,17 shifted into flexion, thus improving The procedure of choice for swan- grasp of small and large objects. neck deformity was lateral-band Summary Those authors also found that translocation, as described by operative correction of boutonniere Zancolli. As the patient population A successful operative result in the deformity by reconstruction of the from which the first study16 was correction of a swan-neck or bou- extensor mechanism was less reli- derived was small, the causes were tonniere deformity in a rheumatoid able than operative correction of diverse, and the follow-up was hand depends on a complete pre- swan-neck deformities, as the deteri- short, the insight provided by this operative examination, correct oration over time was greater. Only study is limited. staging of the deformity and prop- 4 of 19 patients could extend their In the other clinical study,17 31 er timing of operative treatment. PIP joints beyond 20 degrees of flex- stiff swan-neck deformities, with or Although operative correction fre- ion, and 11 of 19 patients had exten- without PIP joint destruction, were quently reduces pain and increases sion deficits of 45 degrees or more at treated by synovectomy, lateral- function, the surgeon must remain the PIP joint. Currently, the authors band release and translocation, and realistically reserved as to expecta- recommend arthrodesis of the PIP dorsal capsulectomy. The improve- tions regarding the long-term joint in digits with severe rheuma- ment in the position of the arc of results of procedures used to cor- toid boutonniere deformities. motion into flexion was similar to rect these deformities.

References

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100 Journal of the American Academy of Orthopaedic Surgeons