Fracture Dislocations of the Proximal Interphalangeal Joint

Home , Joint, Lip, Palmar plate, Pilon fracture

FRACTURE DISLOCATIONS OF THE PROXIMAL INTERPHALANGEAL JOINT

BY RICHARD KANG, MD, AND PETER J. STERN, MD

Fracture dislocations of the proximal interphalangeal joint may occur by several different mechanisms of injury and are of 3 basic fracture patterns: palmar lip fractures, dorsal lip fractures, and pilon fractures. Proper treatment of these injuries is predicated on maintenance of concentric reduction of the joint, restoration of joint stability, and institution of early motion. Anatomic reconstitution of the articular surface, though ideal, is less important. Many methods are available to treat these injuries. Understanding the fracture within the context of a stability-based classiﬁ- cation system helps to guide in the selection of the most appropriate treatment. Copyright © 2002 by the American Society for Surgery of the Hand

racture dislocations of the proximal interphalan- lanx: (1) palmar lip fractures, (2) dorsal lip fractures, geal joint are common injuries that, when inad- and (3) pilon fractures (Fig 1). These fracture patterns Fequately understood, can be confusing for the are the result of characteristic mechanisms of injury. physician to treat. Worse, inappropriate treatment can Pure hyperextension may cause an avulsion fracture lead to a dysfunctional joint secondary to persistent pain, from the base of the middle phalanx. More commonly, stiffness, and posttraumatic degenerative arthrosis. A however, PIPJ fracture dislocations occur as a result of thorough understanding of the biomechanics of the in- an axial load, the specific fracture pattern depending jured proximal interphalangeal joint, the principles of its on the amount of flexion of the PIPJ at the time of treatment, and the available treatment options is essen- axial loading. tial to the proper management of these injuries. Palmar lip fractures at the articular base of the middle phalanx are the most frequently encountered FRACTURE TYPES AND MECHANISMS OF INJURY PIPJ fracture dislocation type (Fig 1A). With hyper- roximal interphalangeal joint (PIPJ) fracture dis- extension only, the palmar plate may rupture at its Plocations can be classified into 3 types based on distal insertion on the middle phalanx, which can the fracture geometry of the base of the middle pha- result in pure dorsal dislocation of the middle phalanx on the proximal phalangeal head. Alternatively, the palmar plate may avulse a fragment of bone from the From the Department of Orthopaedic Surgery, University of Cincin- palmar lip of the middle phalanx; these fracture frag- nati, Cincinnati, OH. Address reprint requests to Peter J. Stern, MD, 2800 Winslow Ave, ments vary in size and displacement, but are generally Suite 401, Cincinnati, OH 45206. E-mail: [email protected] not comminuted. Fracture dislocation of the PIPJ owing to axial loading of the joint in some degree of Copyright © 2002 by the American Society for Surgery of the Hand 1531-0914/02/0202-0004$35.00/0 flexion results in a fracture of the category coined doi:10.1053/jssh.2002.33317 impaction shear fractures.1 In this category, an axial

JOURNAL OF THE AMERICAN SOCIETY FOR SURGERY OF THE HAND ⅐ VOL. 2, NO. 2, MAY 2002 47 48 FRACTURE DISLOCATIONS OF THE PIP JOINT ⅐ KANG & STERN

surface of the base of the middle phalanx are spared. There may also be injury to the hyaline cartilage of the head of the proximal phalanx. Dorsal lip fractures of the middle phalanx occur in an analogous fashion as palmar lip fractures (Fig 1B) though they are less common. Hyperﬂexion of the PIPJ may result in rupture of the central tendon through its substance or its insertion; the central tendon may also avulse a fragment of dorsal bone from the base of the middle phalanx. Axial load with the PIPJ in extension leads to a dorsal lip fracture of the base of middle phalanx from an impaction shear mechanism similar to that described for palmar lip fractures.2 Pilon fractures of the PIPJ have been deﬁned by Stern et al3 as those in which both the palmar and dorsal cortical margins of the base of the middle phalanx are disrupted and the central articular surface is extensively comminuted and impacted into the underlying metaphyseal bone (Fig 1C).3 They result from a high-energy axial load applied to the PIPJ in full extension.

JOINT STABILITY

FIGURE 1. Proximal interphalangeal fracture dislocation ractures of the base of the middle phalanx may types. (A) Palmar lip fracture with dorsal subluxation. A V- lead to instability of the proximal interphalangeal shaped gap can be appreciated between the head of the F proximal phalanx and the intact dorsal base of the middle joint. Several anatomic and biomechanical factors phalanx because of lack of articular congruency. (B) Dorsal must be considered in understanding the tendency lip fracture with palmar subluxation. (C) Pilon fracture. Both toward subluxation or dislocation of the middle pha- palmar and dorsal cortical margins are fractured and the central articular fracture fragments are impacted and commi- lanx on the head of the proximal phalanx. An under- nuted. (Adapted and reprinted with permission.1) standing of PIPJ stability is central to a functionally useful classification that is helpful in guiding appropriate treatment of PIPJ fracture dislocations. load across the PIPJ drives the middle phalangeal base In palmar lip fractures, the normally cup-shaped onto the proximal phalangeal head. Because of the base of the middle phalanx is converted into one with flexed position of the PIPJ, the axial load creates a a dorsal proximal to palmar distal orientation (Fig 2). palmar to dorsal force gradient across the articular Combining this anatomic alteration with the loss of surface of the base of the middle phalanx with greater the restraint of the palmar plate at the palmar base of force concentrated at its palmar aspect. The palmar the middle phalanx allows the central slip of the base of the middle phalanx is thus sheared off and, extensor tendon to subluxate or dislocate the base of with continued displacement of the proximal phalan- the middle phalanx dorsally onto the head of the geal head, the palmar fracture fragment is then im- proximal phalanx. This tendency is facilitated by the pacted into the underlying metaphyseal bone, nearly pull of the flexor digitorum superficialis, which tilts always causing fracture comminution.2 This fracture the base of the middle phalanx dorsally about the pattern may involve up to 80% of the palmar aspect of articular margin of the fracture.4 Restoration of sta- the middle phalanx base; by definition, however, the bility is predicated on reestablishing the palmar but- dorsal cortex and some portion of the dorsal articular tress by restoring the articular geometry of the palmar FRACTURE DISLOCATIONS OF THE PIP JOINT ⅐ KANG & STERN 49

extension is then obtained to confirm stability of the reduction. If the joint subluxates or dislocates, it is necessary to identify the degree of flexion at which this occurs; use of fluoroscopy is especially helpful in this determination. In an analogous way, dorsal lip fractures may result in subluxation or dislocation in a palmar direction. The pull of the flexor digitorum superficialis, no longer opposed by the central slip of the extensor tendon, acts to subluxate or dislocate the base of the middle phalanx palmarward.

CLASSIFICATION FIGURE 2. Mechanisms of instability in palmar lip fractures. The pull of the intact central slip of the extensor mechanism ased on fracture pattern and joint stability, a is able to subluxate or dislocate the base of the middle classification system for fracture dislocations of phalanx over the head of the proximal phalanx because of (1) B the slope of the fractured base of the middle phalanx, (2) the the proximal interphalangeal joint has been estab- loss of the palmar plate restraint, and (3) the tilting moment lished that is useful with respect to selection of the about the fracture margin caused by the pull of the flexor best option for treatment of these injuries (Table 1).1 digitorum superficialis. P1, proximal phalanx; P2, middle phalanx; EXT, central tendon; VP, palmar plate; FDS, flexor digitorum superficialis. (Adapted and reprinted with permis- Palmar Lip-Fracture Classification sion.1) This classification builds on previous ones that have stratified PIPJ fracture dislocations according to the base of the middle phalanx with respect to joint percentage of fractured palmar articular surface at the congruency and concentricity. base of the middle phalanx.4,5 Fractures that involve Given that the primary variable in the earlier- less than 30% are usually, but not always, stable; 30% mentioned scenario is the fracture itself, it stands to to 50% are of tenuous stability; and greater than 50% reason, then, that the size of the fracture fragment(s) is are unstable (Fig 3). By adding the assessment of the major determinant of stability of the injured clinical stability to those based purely on anatomic PIPJ. Though in large part true, equally important is criteria, this classification divides palmar lip fractures the determination of the clinical stability of the re- into 3 functional groups: stable, tenuous, and un- duced PIPJ fracture dislocation by physical examina- stable.1 tion. After digital block anesthesia, the surgeon re- Stable fracture dislocations involve less than 30% of duces the PIPJ and watches for subluxation or the palmar articular base of the middle phalanx, and, dislocation while the patient actively extends the after reduction, the joint remains stable with the PIPJ joint. A true lateral radiograph of the PIPJ in full fully extended. Congruent reduction of the PIPJ

TABLE 1 Classiﬁcation of Proximal Interphalangeal Joint Fracture Dislocations

Articular Surface Fracture Type Stability Involvement Comment Palmar lip fracture Stable Ͻ30% Reduced in full extension Tenuous 30%-50% Requires Ͻ30° of ﬂexion to maintain reduction Unstable 30%-50% or Ͼ50% Requires Ͼ30° of ﬂexion to maintain reduction Dorsal lip fracture Stable Ͻ50% Reduced in full extension Unstable Any percentage Palmar subluxation/dislocation in full extension Pilon fracture Unstable 100% Grossly unstable 50 FRACTURE DISLOCATIONS OF THE PIP JOINT ⅐ KANG & STERN

PRINCIPLES OF TREATMENT

f paramount importance in the treatment of Oproximal interphalangeal joint fracture dislocations is the correction of joint subluxation or dislocation and the maintenance of concentric reduction. Based on multiple studies, the best functional results are obtained by treatments in which the normal gliding arc of motion of the base of the middle phalanx FIGURE 3. Classification of palmar lip fractures. Stable frac- about the head of the proximal phalanx is reestab- tures involve less than 30% of the palmar base of the middle phalanx and show no tendency to subluxation in full exten- lished; with persistent subluxation of the PIPJ, mo- sion. Tenuous fractures involve 30% to 50% of the base and tion occurs by hinging at the fracture margin and remain concentrically reduced with less than 30° of flexion. portends a poor result.6-8 Treatment, therefore, must Unstable fractures include all those involving greater than 50% of the articular surface, as well as those involving 30% be directed at correction of PIPJ subluxation and to 50% that require greater than 30° of flexion to maintain restoration of joint stability to permit a normal arc of reduction. (Adapted and reprinted with permission.1) joint motion. Whenever possible, early motion should be instituted to minimize adhesions and contractures should be shown by radiographs of the joint in this and to enhance cartilage and soft-tissue healing. An- position. atomic reduction of the fractured articular surface, Tenuous fracture dislocations of the PIPJ are those though desirable, is not a prerequisite for good PIPJ in which 30% to 50% of the palmar lip is fractured function.3,9-11 and, once reduced, are stable in reduction with less than 30° of flexion. If the joint requires more than 30° TREATMENT OPTIONS of flexion to maintain congruent reduction, it is considered unstable. reatment methods of proximal interphalangeal Unstable PIPJ fractures dislocations include all joint fracture dislocations are grouped into 5 fractures involving greater than 50% of the palmar T broad categories: immobilization, protected motion, joint surface of the middle phalanx, as well as those traction, open reduction and internal fixation, and involving 30% to 50% that require greater than 30° buttress reconstruction (Fig 4). of flexion to maintain congruent reduction.

Dorsal Lip Fracture Classification Immobilization Dorsal lip fractures differ from palmar lip fractures Static splinting or transarticular Kirschner wire in that the position of maximal stability is in full fixation may be used to immobilize the PIPJ in a extension. Further, it is usually necessary to immobi- reduced position.4,12 Though a simple technique, lize the PIPJ in this position to reestablish continuity there are 2 major disadvantages of immobilization. of the central slip of the extensor mechanism. In full Prolonged immobilization (Ͼ3 wks) often leads to extension, the PIPJ is either stable or unstable—thus, significant permanent stiffness and loss of range of the tenuous group is eliminated. motion. Furthermore, in unstable fractures, this Stable dorsal lip fractures are usually non- or min- method is frequently unable to reliably restore stabil- imally displaced avulsion fractures from the dorsal ity to the joint and recurrent subluxation or disloca- base of the middle phalanx involving up to 50% of the tion often results after cessation of immobilization. joint surface. Positioned in full extension, the PIPJ remains reduced with no evidence of palmar sublux- Protected Motion ation as shown by a true lateral radiograph. With protected motion, the PIPJ is permitted to Unstable dorsal lip fractures are any that permit move in an arc through which the joint remains palmar subluxation or dislocation of the middle pha- concentrically reduced, but is restricted from positions langeal base with the middle phalanx in full exten- in which it is unstable. In those cases requiring only sion. protection from hyperextension, buddy taping may be FRACTURE DISLOCATIONS OF THE PIP JOINT ⅐ KANG & STERN 51

FIGURE 4. Treatment algo- rithm for proximal interphalangeal joint fracture dislocations.

used. A figure of 8 splint is the most simple method proximal palmar direction, approximately 30° to the to treat a stable PIPJ fracture dislocation when a long axis of the bone; thus, the wire acts as a mechan- slight degree of flexion (ie, a PIPJ extension block) is ical block to extension while allowing active flexion. required to maintain reduction. Both of these methods are advantageous in that they permit early motion. Traction McElfresh et al5 introduced the dorsal extension Many traction methods or devices have been devel- block splint—a short arm cast with an alumafoam oped that effectively maintain PIPJ reduction after dorsal PIPJ extension-blocking outrigger to permit fracture dislocation. Nearly all use longitudinal trac- unrestricted active flexion of the reduced PIPJ while tion either alone or in combination with a palmarly blocking extension just short of the point at which the directed force to maintain reduction, and most permit joint begins to subluxate dorsally. This splinting tech- active or passive PIPJ motion. Robertson et al15 de- nique, as well as later modifications thereof,6,13 main- scribed a static traction system that uses 1 pin tains joint reduction during fracture consolidation and through the distal aspect of the middle phalanx to soft-tissue healing while encouraging early motion. apply traction across the PIPJ while 2 other pins, 1 Whether the dorsal blocking splint is forearm-, hand-, through the neck of the proximal phalanx and 1 or digit-based, the critical component is the dorsal through the base of the middle phalanx, pull in op- alumafoam over the proximal phalanx, the PIPJ, and posite directions, to correct dorsal subluxation. the middle phalanx. The proximal phalanx must be Schenck10 devised a system in which longitudinal well secured to the splint with tape to prevent over- traction is applied to a transosseus wire through the extension of the PIPJ such as occurs if the proximal distal aspect of the middle phalanx via a rubber band phalanx is allowed to pull away from the splint. attached to a movable component on an arcuate splint, Additionally, the splint must be bent at the PIPJ such thus, allowing passive PIPJ motion. Morgan et al9 that the middle phalanx is dorsally blocked from combined these 2 methods in a technique that pro- extending past the point at which subluxation occurs vides traction and relocation forces with passive PIPJ as confirmed by a true lateral radiograph. motion. One transosseous wire is placed through the By using the same concept, Viegas14 proposed ex- distal aspect of the middle phalanx and 1 through the tension block pinning to achieve the same effect. After axis of PIPJ rotation in the head of the proximal reduction, the PIPJ is held at 90° of flexion, and a phalanx. Both wires are then attached via rubber percutaneous Kirschner wire is then placed into the bands to an arcuate frame such that the distal wire head of the proximal phalanx in a distal dorsal to provided longitudinal traction and the proximal wire 52 FRACTURE DISLOCATIONS OF THE PIP JOINT ⅐ KANG & STERN

FIGURE 5. Eaton palmar plate arthroplasty. (A) The palmar plate is advanced into the fracture defect in the base of the middle phalanx to resurface the articular surface and to restrain dorsal subluxation. (B) Dorsal subluxation may recur if advancement of the palmar plate is unable to adequately fill the void left by the palmar lip fracture. By filling this space with a slip of flexor digitorum superficialis (C) or bone graft or fracture fragments (D), the cup-shaped geometry of the middle phalangeal base and the palmar buttressing effect is reestablished. VP, palmar plate; P1, proximal phalanx; P2, middle phalanx; EXT, central tendon; FDS, flexor digitorum superficialis. (Adapted and reprinted with permission.1) provided a relocation force; movement of both about interfragmentary compression screw technique has be- the arcuate frame permits passive motion of the PIPJ. come more practical with the availability of smaller Agee16 developed an ingenious linkage of 3 Kirschner self-tapping screws with low profile heads. With open wires and a rubber band to create a force couple that reduction and internal fixation, cancellous bone graft effects PIPJ reduction by simultaneously levering the must often be used to fill a metaphyseal void left after base of the middle phalanx palmarly and lifting the elevation of a depressed fracture fragment.8,19,22 The head of the proximal phalanx dorsally. This force use of a hyperextension gunstock volar approach to the couple maintains joint reduction through a full active PIPJ can provide superb joint visualization, though range of motion. Hastings and Ernst17 and Kasparyn stable fixation, usually by miniscrews or cerclage wire, and Hotchkiss18 have designed dynamic external fix- is important for early motion.20 ators that simultaneously provide longitudinal traction, maintain joint reduction, and permit passive and Buttress Reconstruction active motion.8 Two unique methods have been designed for the treatment of unstable palmar lip fractures: palmar Open Reduction and Internal Fixation plate arthroplasty and hamate osteochondral autograft Open reduction and internal fixation is a viable arthroplasty. Described by Eaton and Malerich,24 pal- option for treatment of PIPJ fracture dislocations mar plate arthroplasty involves advancement of the when there is little or no comminution and the frac- palmar plate into the defect at the base of the middle ture fragments are large enough to accommodate fix- phalanx to resurface the damaged articular surface and ation. Lag screws, Kirschner wires, tension banding, to restrain dorsal subluxation of the joint (Fig 5A).24 cerclage wiring, and pull-out sutures have all been The procedure and useful modifications have been advocated alone or in combination.19-23 The use of well described in the literature.24-26 However, 3 FRACTURE DISLOCATIONS OF THE PIP JOINT ⅐ KANG & STERN 53

points warrant mention here. First, the PIPJ is subject to ensure that the cup-shaped sagittal profile of the to recurrent dorsal subluxation particularly if the pal- articular base of the middle phalanx is recreated (Fig mar defect is not adequately filled by the thickness of 6D and F). Properly performed, this technique pro- the advanced palmar plate.4,24 This occurs as the head vides immediate stability to the joint, thus, permit- of the proximal phalanx forces the palmar plate into ting early motion (Fig 6G and H). the fracture defect in the base of the middle phalanx thus allowing dorsal subluxation of the joint (Fig 5B). TREATMENT OF PALMAR LIP FRACTURES It is thus essential to provide unyielding support to the palmar plate arthroplasty by filling any distal he goals of treatment of palmar lip fractures are bony void. Although a slip of flexor digitorum super- Tto obtain and maintain concentric reduction of ficialis may be used to this effect (Fig 5C), it is better the joint to reestablish joint stability and a normal performed with bony fracture fragments or bone graft gliding arc of motion of the articular base of the (Fig 5D).1 Second, redislocation is a real concern, middle phalanx about the head of the proximal especially when greater than 50% of the base of the phalanx. Use of the stability-based classification middle phalanx is fractured.27 Finally, a dynamic ex- system for palmar lip fractures as outlined earlier, ternal fixator can be used in conjunction with a palmar simplifies selection of an appropriate treatment mo- plate arthroplasty to initiate early range of motion.1 dality. In an effort to reconstruct the palmar buttress in unstable palmar lip fractures, Hastings et al28 have Stable Palmar Lip Fractures proposed a novel approach by using the anatomic These fractures involve less than 30% of the palmar similarity in contour between the palmar articular articular surface of the middle phalangeal base and clinical testing shows that the PIPJ remains congru- surface of the base of the middle phalanx and the ently reduced throughout a full arc of motion. There- hamate articulation with the bases of the 4th and 5th fore, treatment is focused on maximizing motion. metacarpals (Fig 6).28 The PIPJ is first exposed Treatment options include static splinting, buddy through a volar approach to allow visualization of the taping, figure of 8 splint, and extension block splint. fractured palmar articular base of the middle phalanx In 1 study, static splinting is not recommended for (Fig 6B). A dorsal approach is then used to expose the the treatment of stable palmar lip fractures because its articulation between the hamate and the 4th and 5th use has been associated with increased stiffness when metacarpals (Fig 6C). A small straight osteotome is compared with buddy taping; its use has also been then used to remove a rectangular segment of hamate associated with loss of flexion and flexion contrac- at its distal articular margin centered between the 4th ture.29 This same study also showed that displacement and 5th metacarpals. The width and depth of the and nonunion of the palmar lip fracture fragment had articular surface of the segment should match the no bearing on the outcome of stable palmar lip frac- width and depth of the palmar lip defect of the base of tures. Stable palmar lip fractures in which the PIPJ the middle phalanx, and the height of the segment does not exhibit a tendency to hyperextend are treated should be sufficient to permit secure fixation with with buddy taping to prevent re-injury while encour- ϳ small ( 1.0-1.5 mm) screws. The palmar base of the aging immediate motion. If the palmar lip fracture middle phalanx is then sculpted with a small os- allows PIPJ hyperextension (which may result in a teotome and rongeur to allow close fit of the hamate swan neck deformity if left uncorrected), we prefer to osteochondral autograft at its articular, cortical, and use a figure of 8 splint or a dorsal blocking splint that cancellous surfaces (Fig 6D). The graft is oriented such permits full active flexion but prevents the last 10° to that its original dorsal surface becomes the new pal- 15° of extension to facilitate palmar plate healing. mar surface and is trimmed at its radial and ulnar After 3 weeks, the splint is adjusted to allow an margins to reconstruct the outline of the palmar mid- additional 10° of extension per week. dle phalangeal base as viewed en face. Two small compression screws are then placed in a palmar to Tenuous Palmar Lip Fractures dorsal direction to fix the graft to the defect (Fig 6E). These fractures involve 30% to 50% of the palmar Care should be taken in fitting the graft to the defect articular surface of the middle phalanx base and clin- 54 FRACTURE DISLOCATIONS OF THE PIP JOINT ⅐ KANG & STERN

FIGURE 6. Hamate osteochondral autograft arthroplasty. (A) Radiographs show an unstable palmar lip fracture. (B) Over 50% of palmar base of the middle phalanx was fractured resulting in a large defect (arrow). P1, proximal phalanx; P2, middle phalanx. (C) The hamate articulation with the bases of the 4th and 5th metacarpal is anatomically similar to the articular surface of the palmar base of the middle phalanx. H, hamate; 4, 4th metacarpal base; 5, 5th metacarpal base. (D) The hamate osteochondral autograft was used to reestablish the cup-shaped geometry of the base of the middle phalanx. (E) Two small lag screws (1.0 mm) were used to secure the hamate osteochondral autograft to the defect in the palmar base of the middle phalanx. Intraoperatively, congruent joint reduction in full extension has been restored. (F) Radiographs taken 2 months after hamate osteochondral autograft show a stable proximal interphalangeal joint with excellent anatomic restoration of the articular contour of the base of the middle phalanx. (G and H) Excellent active range of motion of the proximal interphalangeal joint was achieved. (Reprinted with permission.1) FRACTURE DISLOCATIONS OF THE PIP JOINT ⅐ KANG & STERN 55

Figure 6. (Continued) ical testing shows that the PIPJ maintains concentric proximal phalanx should be securely bound to the reduction with less than 30° of flexion. Treatment is splint to prevent the digit from pulling away from the directed at maintaining concentric joint reduction splint and inadvertently permitting more than the whereas the palmar fracture fragments consolidate to desired degree of extension at the PIPJ (Fig 7). Once restore the palmar buttress. Treatment options in- the fracture dislocation has been reduced, and the clude static splint, transarticular pin, figure of 8 dorsal blocking splint applied, it is important to splint, extension block splint, extension block pin, confirm with true lateral radiographs that the PIPJ is traction devices, dynamic external fixation, and open concentrically reduced at the point of maximum ex- reduction and internal fixation. Immobilization by tension allowed by the splint. Dorsal subluxation of static splint or transarticular pin is effective in restor- the middle phalanx must be corrected by increasing ing stability to the joint, but is too frequently asso- the flexion angle of the splint. If greater than 30° of ciated with postimmobilization stiffness and is not flexion is required to achieve and maintain reduction, recommended. Traction, dynamic external fixation, the fracture dislocation should be reclassified as un- and open reduction and internal fixation are unneces- stable, and an appropriate treatment method selected. sarily complex and require surgical intervention with The limit of extension on the splint should be in- all of its attendant risks. creased 10° weekly with radiographic confirmation of We prefer the simple but effective method of ex- joint reduction at each change. If subluxation recurs at tension block splinting for treatment of tenuous pal- any interval, the splint is restored to its previous mar lip fractures.5,6,13 Regardless of the specific splint angle. Once the PIPJ has attained full stable extension design used (ie, forearm-, hand-, or digit-based), the (usually 6-8 wks), the splint is discontinued, and 56 FRACTURE DISLOCATIONS OF THE PIP JOINT ⅐ KANG & STERN

FIGURE 7. When using an extension block splint, the proximal phalanx must be firmly affixed to the splint with tape to prevent loss of extension blocking by pulling away of the finger from the splint.

buddy taping used to protect the joint for another When fracture fragments are of sufficient size to accom- several weeks. modate fixation with screws, Kirschner wires, tension In a technical variation of extension block splint- band wires, cerclage wires, or pull-out wires, open re- ing, extension block pinning, as advocated by Vie- duction and internal fixation20 should be used to restore gas,14 may be used to treat tenuous palmar lip frac- the palmar buttress. Frequently, however, one finds tures. Active flexion of the PIPJ is encouraged during small, comminuted, and impacted fragments that re- the 4- to 6-week period that the extension block pin quire alternative techniques. In cases with one relatively is in place. Thereafter, active and passive range of large fragment volarly and comminution of the middle motion exercises are used to regain full extension. aspect of the joint, cerclage wiring, as described by Unstable Palmar Lip Fractures Weiss, can provide a stable construct providing inter- This group of fractures involves all those involving fragmentary compression and allowing early range of 22 greater than 50% of the palmar articular surface of the motion (Fig 8). middle phalanx base and those involving 30% to 50%, If traction across the PIPJ is able to effect both which require more than 30° of flexion to maintain fracture alignment by ligmentotaxis and concentric concentric reduction of the PIPJ. Treatment is aimed at joint reduction, traction or dynamic external fixation restoring the stabilizing cup-shaped geometry of the base may be used to maintain concentric joint reduction of the middle phalanx by reconstructing its palmar de- while the fracture heals. When this is unsuccessful, ficiency, which is responsible for the instability of these restoration of stable geometry to the base of the fractures. Treatment options include open reduction and middle phalanx requires a reconstructive procedure internal fixation, palmar plate arthroplasty, and hamate such as palmar plate arthroplasty or hamate osteo- osteochondral autograft arthroplasty. Traction or dy- chondral autograft arthroplasty. Immediately after namic external fixation may also be used alone or in restoration or reconstruction of the palmar base of the conjunction with any of the earlier-mentioned methods. middle phalanx, dynamic external fixation may be FRACTURE DISLOCATIONS OF THE PIP JOINT ⅐ KANG & STERN 57

FIGURE 8. In highly comminuted fractures of the base of the middle phalanx, a 22-gauge steel cerclage wire can be used to stabilize the fragments by providing circumferential compression with wire tightening. used to maintain joint reduction, protect the healing capsulotomy, and extensor tenolysis. Stability was main- bone and soft tissues, and institute early active and tained by a transarticular pin placed with the joint at 90° passive range of motion exercises. of flexion for less than 2 weeks. Then, a dorsal extension block splint at 60° was initiated allowing active flexion; TREATMENT OF CHRONIC DORSAL FRACTURE the angle was gradually decreased over a 4-week period DISLOCATIONS after which immobilization was discontinued. Others have used corrective osteotomy34 or palmar plate arthro- almar lip fractures with associated dorsal PIPJ dis- plasty24 to reestablish the cup-shaped geometry of the Plocations that are missed, neglected, or incorrectly base of the middle phalanx to restore stability to the treated lead to chronic dorsal fracture dislocations. In joint. Zemel et al34 proposed corrective osteotomy in such cases, joint flexion is limited to that allowed by which the palmar articular surface and the central de- hinging or pivoting of the middle phalangeal base about pressed articular fragments are levered back into position the dorsal margin of the fracture resulting in articular and supported by distal radius bone graft. Our preferred erosion and joint stiffness. In deciding treatment for a method is palmar plate arthroplasty because it simulta- chronic PIPJ fracture dislocation, it is first necessary to neously resurfaces the palmar articular surface of the determine whether or not the remaining articular sur- middle phalanx, restores the palmar buttress, and tight- faces have undergone significant degenerative changes ens the palmar plate. Though current experience is lim- based on radiographic assessment. With significant post- ited, we have also successfully used hamate osteochondral traumatic arthrosis, silicone implant arthroplasty30,31 or autograft arthroplasty for chronic dorsal fracture disloca- arthrodesis32 may be better options. If the remaining tions of the PIPJ. articular surface quality is good, the goals of treatment are, once again, to obtain and to maintain concentric TREATMENT OF DORSAL LIP FRACTURES PIPJ reduction to restore functional motion. Donaldson and Millender33 performed open reduction through a s with palmar lip fractures, the goals of treatment lateral approach by clearing the palmar retrocondylar Aof dorsal lip fractures are to obtain and maintain space of proximal phalanx of scar and adhesions, dorsal concentric reduction of the joint to reestablish joint 58 FRACTURE DISLOCATIONS OF THE PIP JOINT ⅐ KANG & STERN

stability. In addition, continuity of the central slip of the a dynamic external fixator has been advocated to limit extensor apparatus must be reestablished. stiffness and PIPJ contracture.8,17 Alternatively, in cases in which the fracture fragment is displaced less Stable Fractures than 2 mm and moves with the base of the middle The PIPJ does not show palmar subluxation with phalanx, traction and immediate motion have been stable dorsal lip fractures. Therefore, the primary treat- used successfully to correct joint subluxation and re- ment goal is to reestablish continuity of the central slip. store joint stability with minimal extensor lag.9 Though the fracture fragment may vary in size, most are not significantly comminuted and will heal with osseous TREATMENT OF PILON FRACTURES or stable fibrous union. At issue, however, is the amount of fragment separation acceptable with respect to com- ilon fractures involve both palmar and dorsal lip promise of central slip function. fractures with extensive central depression and In our experience, stable dorsal lip fractures with P comminution and are unstable. The goal of treatment less than 2 mm of fragment separation may be treated is to reestablish a concentric gliding arc of motion of by immobilization of the PIPJ in extension by splint the base of the middle phalanx about the head of the or transarticular Kirschner wire with acceptable re- proximal phalanx. To achieve this goal, the proximal sults. Duration of immobilization should be 3 to 4 and middle phalanges must be collinear and the pal- weeks, after which a dynamic extension splint should mar and dorsal fracture fragments must realign to be placed to permit active flexion. At 6 weeks, passive reapproximate the cup-shaped geometry of the base of flexion and strengthening exercises should be initi- the middle phalanx. Exact anatomic reduction of the ated. It should be noted that immobilization must not joint surface is far less important than the institution include the distal interphalangeal joint, which should of early motion. Traction accomplishes these pre- be started immediately on active and passive range- requisites and has been shown to be effective in treat- of-motion exercises. ing pilon fractures.3,9,10 In dorsal lip fractures with fragment displacement Although any of the traction methods described may greater than 2 mm, unacceptable extensor lag may be used successfully to treat pilon fractures, certain prin- result unless treated with open reduction and internal ciples apply to all. Splint immobilization is to be dis- fixation. Fixation options include Kirschner wires couraged Traction is a reasonable alternative and is our with or without a tension band wire, loop wire, pull- treatment of choice. It should effect collinear alignment out suture, suture anchor, or lag screws; with stable of the proximal and middle phalanges with no angula- fixation, immediate postoperative motion is initiated. tion in the coronal plane as well as good overall alignment of the fracture fragments in the sagittal plane as Unstable Fractures shown by radiographs. The traction method chosen If the PIPJ is subluxated or dislocated anteriorly should permit immediate mobilization of the joint. after closed reduction, it is by definition unstable. Traction is discontinued at 6 weeks when the fracture Treatment is directed at obtaining and maintaining fragments have consolidated; aggressive range-of-motion concentric joint reduction to restore integrity of the exercises are continued. Treated as such, these fractures central slip. If the fracture fragments are large enough, frequently remodel,3 resulting in an acceptable arc of this is achieved by open reduction and internal fixa- motion with minimal pain. tion. Highly comminuted fractures may be treated by Although not contraindicated, we have found open closed reduction and percutaneous pinning with the reduction and internal fixation risky, and complica- PIPJ in full extension to allow consolidation of the tions such as loss of reduction, stiffness, and infection fracture fragments and the insertion of the central slip can arise. if the dorsal buttress of the base of the middle phalanx is restored by reduction of the joint. When this is not the case, some investigators have proposed fragment ACKNOWLEDGMENT elevation with bone grafting,4,35 or central slip suture into the fracture bed. These methods have been asso- The authors thank T. R. Kiefhaber, MD, for sharing ciated with considerable postoperative stiffness; use of his photographs and illustrations. FRACTURE DISLOCATIONS OF THE PIP JOINT ⅐ KANG & STERN 59

REFERENCES

1. Kiefhaber TR. Phalangeal dislocations/periarticular trauma. 19. Freeland AE, Benoist LA. Open reduction and internal fixa- In: Peimer CA, ed. Surgery of the hand and upper extremity. tion method for fractures at the proximal interphalangeal Vol. 1. New York: McGraw-Hill, 1996:939-972. joint. Hand Clin 1994;10:239-250. 2. Akagi T, Hashizume H, Inoue H, Ogura T, Nagayama N. 20. Green A, Smith J, Redding M, Akelman E. Acute open Computer simulation analysis of fracture dislocation of the reduction and rigid internal fixation of proximal interphalan- proximal interphalangeal joint using the finite element geal joint fracture dislocation. J Hand Surg [Am] 1992;17A: method. Acta Med Okayama 1994;48:263-270. 512-517. 3. Stern PJ, Roman RJ, Kiefhaber TR, McDonough JJ. Pilon 21. Wilson JN, Rowland SA. Fracture-dislocation of the proxi- fractures of the proximal interphalangeal joint. J Hand Surg mal interphalangeal joint of the finger. Treatment by open [Am] 1991;16A:844-850. reduction and internal fixation. J Bone Joint Surg Am 1966; 4. Hastings H II, Carroll CIV. Treatment of closed articular 48A:493-502. fractures of the metacarpophalangeal and proximal interpha- 22. Weiss A-PC. Cerclage fixation for fracture dislocation of the langeal joints. Hand Clin 1988;4:503-527. proximal interphalangeal joint. Clin Orthop 1996;327:21-28. 5. McElfresh EC, Dobyns JH, O’Brien ET. Management of 23. Jupiter JB, Sheppard JE. Tension wire fixation of avulsion fracture-dislocation of the proximal interphalangeal joints by fractures in the hand. Clin Orthop 1987;214:113-120. extension-block splinting. J Bone Joint Surg Am 1972;54A: 24. Eaton RG, Malerich MM. Volar plate arthroplasty for the 1705-1711. proximal interphalangeal joint: a ten year review. J Hand 6. Hamer DW, Quinton DN. Dorsal fracture subluxation of the Surg 1980;5:260-268. proximal interphalangeal joints treated by extension block 25. Durham-Smith G, McCarten GM. Volar plate arthroplasty splintage. J Hand Surg [Br] 1992;17B:586-590. for closed proximal interphalangeal joint injuries. J Hand 7. Inanami H, Ninomiya S, Okutsu I, Tarui T. Dynamic exter- Surg [Br] 1992;17B:422-428. nal finger fixator for fracture dislocation of the proximal 26. Bilos ZJ, Vender MI, Bonavolonta M, Knutson KL. Fracture interphalangeal joint. J Hand Surg [Am] 1993;18A:160-194. subluxation of proximal interphalangeal joint treated by pal- 8. Krakauer JD, Stern PJ. Hinged device for fractures involving mar plate advancement. J Hand Surg [Am] 1994;19:189- the proximal interphalangeal joint. Clin Orthop 1996;327: 195. 29-37. 27. Deitch M, Kiefhaber T, Comisar B, Stern P. Dorsal fracture 9. Morgan JP, Gordon DA, Klug MS, Perry PE, Barre PS. dislocations of the proximal interphalangeal joint: surgical Dynamic digital traction for unstable comminuted intra- complications and long-term results. J Hand Surg [Am] articular fracture-dislocations of the proximal interphalangeal 1999;24A:914-923. joint. J Hand Surg [Am] 1995;20A:565-573. 28. Hastings H, Capo J, Steinberg B, Stern P. Hemicondylar 10. Schenck RR. Dynamic traction and early passive movement hamate replacement arthroplasty for proximal interphalan- for fractures for the proximal interphalangeal joint. J Hand geal joint fracture/dislocations (abstr). Presented at the 54th Surg [Am] 1986;11A:850-858. Annual Meeting of the American Society for Surgery of the 11. Agee JM. Unstable fracture dislocations of the proximal Hand, Boston, MA, 1999. interphalangeal joint. Treatment with the force couple splint. 29. Phair IC, Quinton DN, Allen MJ. The conservative manage- Clin Orthop 1987;214:101-112. ment of volar avulsion fractures of the P.I.P. joint. J Hand 12. Zemel NP, Stark HH. Problem fractures and dislocations of Surg [Br] 1989;14B:168-170. the hand. In: Bassett FH III, ed. Injuries to Bone and Muscle. 30. Leddy JP, Dennis T. Tendon injuries. In: Strickland JW, AAOS Instructional Course Lectures. St. Louis: CV Mosby, Rettig AC, eds. Hand injuries in athletes. Philadelphia: W.B. 1988:235-249. Saunders, 1992:175-207. 13. Strong ML. A new method of extension block splinting 31. Swanson AB, de Groot Swanson G. Flexible implant resection for the proximal interphalangeal joint—preliminary report. arthroplasty of the proximal interphalangeal joint. In: J Hand Surg [Am] 1980;7A:77-78. Schenck RR, ed. Hand clinics. Philadelphia: W.B. Saunders, 14. Viegas SF. Extension block pinning for proximal interpha- 1994:261-268. langeal joint fracture dislocations: preliminary report of a new 32. Jones BF, Stern PJ. Interphalangeal joint arthrodesis. In: technique. J Hand Surg [Am] 1992;17A:896-901. Schenck RR, ed. Hand clinics. Philadelphia: W.B. Saunders, 15. Robertson RC, Cawley JJ, Faris AM. Treatment of fracture- 1994:267-276. dislocation of the interphalangeal joints of the hand. J Bone 33. Donaldson WR, Millender LH. Chronic fracture-subluxation Joint Surg 1946;28:68-70. of the proximal interphalangeal joint. J Hand Surg 1978;3: 16. Agee JM. Unstable fracture dislocations of the proximal 149-153. interphalangeal joint of the fingers: a preliminary report of a 34. Zemel NP, Stark HH, Ashworth CR, Boyes JH. Chronic new treatment technique. J Hand Surg 1978;3:386-389. fracture dislocation of the proximal interphalangeal joint— 17. Hastings H II, Ernst JM. Dynamic external fixation for treatment by osteotomy and bone graft. J Hand Surg 1981; fractures of the proximal interphalangeal joint. Hand Clin 6:447-455. 1993;9:659-674. 35. Steel WM. Articular fractures. In: Barton NJ, ed. Fractures of 18. Kasparyn NG, Hotchkiss RN. Dynamic skeletal fixation in the hand and wrist. Edinburgh: Churchill Livingstone, the upper extremity. Hand Clin 1997;13:643-664. 1988:55-73.