Vol 8, No 6, November/December 2000 383 The proximal interphalangeal (PIP) joint has the largest arc of motion (120 degrees) of the three joints in each digit of the hand. It is estimated that this joint accounts for 85% of the motion required to grasp an object. 1 Unfortunately, the PIP joint is unique- ly susceptible to injury and tends to become stiff soon after trauma or im- mobilization. This tendency toward stiffness has been attributed to the pain and instability that may accom- pany injury or to fibrosis of the joint capsule and collateral ligaments. Early mobilization is essential to minimize joint stiffness. Immobili- zation for longer than 3 weeks can result in permanent loss of motion. 2 It is essential for the treating physi- cian to determine which treatment can best achieve sufficient fracture stability and when the fracture is sta- ble enough to permit joint motion. Anatomy and Biomechanics The articular surface of the proximal phalanx is bicondylar and broader volarly. The condyles are slightly asymmetric, and for each individual finger the bone profiles and geome- try differ slightly. Hyaline cartilage covers approximately 210 degrees of the head of the proximal phalanx. The articular surface of the middle phalanx is biconcave with an inter- condylar ridge and is almost com- pletely congruent with the proximal phalangeal surface (Fig. 1). This congruence confers stability to the joint, particularly in the axially loaded finger. The PIP joint functions primarily as a hinge in the coronal plane. The asymmetry of the condyles of the proximal phalanx and the slight incongruence of the articular sur- faces allows a gliding motion of the middle phalanx with a few degrees of rotation and angulation. The asymmetry of the condylar profiles produces rotation of the tip of the finger with flexion; the index finger supinates, and the ring and small fingers pronate. 3 The central slip of the extensor mechanism inserts on a dorsal tuber- cle located just distal to the articular surface of the middle phalanx (Fig. 2). The ligamentous structures of the PIP joint include the collateral liga- ments, the volar plate, the accessory collateral ligaments, and the joint capsule. The collateral ligaments originate from concavities on the lat- eral aspects of the proximal phalanx. They course volarly relative to the midaxis of the joint and insert on a tubercle at the palmar and lateral aspects of the middle phalanx. The dorsal fibers tighten with joint flex- ion, and the palmar fibers tighten with extension. The volarmost fibers blend with the distal volar plate. Dr. Blazar is Assistant Professor of Ortho- paedic Surgery, University of Kentucky College of Medicine, Lexington. Dr. Steinberg is Assistant Professor of Orthopaedic Surgery, University of Pennsylvania School of Medicine, Philadelphia. Reprint requests: Dr. Blazar, University of Kentucky, K401 Kentucky Clinic, 740 South Limestone, Lexington, KY 40536-0284. Copyright 2000 by the American Academy of Orthopaedic Surgeons. Abstract Fractures of the proximal interphalangeal joint constitute a broad spectrum of injuries. An understanding of the anatomy, the potential for joint instability, and the treatment options is essential to management of these fractures. Commonly observed fracture patterns involve one or both condyles of the proxi- mal phalanx or the base of the middle phalanx. Fractures of the middle phalanx may involve the palmar lip or the dorsal lip or may be a "pilon" type of injury involving both the palmar and the dorsal lip with extensive intra-articular com- minution. Intra-articular injuries may lead to joint subluxation or dislocation and must be identified in a timely manner to limit loss of motion, degenerative changes, and impaired function. These injuries range from those requiring minimal intervention to obtain an excellent outcome to those that are challeng- ing to the most experienced surgeon. The treatment options include extension- block splinting, percutaneous pinning, traction, external fixation, open reduc- tion and internal fixation, and volar-plate arthroplasty. Prompt recognition of the complexity of the injury and appropriate management are essential for an optimal functional outcome. J Am Acad Orthop Surg 2000;8:383-390 Fractures of the Proximal Interphalangeal Joint Philip E. Blazar, MD, and David R. Steinberg, MD Proximal Interphalangeal Joint Fractures Journal of the American Academy of Orthopaedic Surgeons 384 The proximal portion of the volar plate has a swallowtail shape. The slender proximal extensions (checkrein ligaments) are somewhat mobile from the underlying proxi- mal phalanx. Transverse branches of the digital arteries course under them to meet in the midline and supply the joint and the vincula of the flexor tendons. The distal por- tion of the volar plate inserts onto the base of the middle phalanx. The attachments to the middle pha- lanx blend with the periosteum of the middle phalanx centrally and are more substantial laterally, where the volar-plate fibers blend with the collateral ligaments. The accessory collateral liga- ments originate just volar to the proper collateral ligaments, but the fibers of the former fan out volarly to insert on the volar plate and the flexor tendon sheath. The acces- sory collateral ligaments are tight in extension and loose in flexion. The dorsal capsule is separate from the overlying extensor mechanism and consists of a minimal synovial lining. 3 The soft-tissue structures that surround the PIP joint contribute to its stability. The volar plate resists joint hyperextension, while the col- lateral ligaments are the primary restraints to motion in the coronal plane. 4 There are a number of sec- ondary stabilizers. At terminal ex- tension, the volar plate and the accessory collateral ligaments as- sume a larger role. In flexion, the proper collateral ligament is tight- ened over the flare of the condyle and becomes the primary stabilizer against lateral displacement. Both the volar plate and at least one col- lateral ligament must be injured for dislocation of the PIP joint to occur. 5 Clinical Evaluation Specific features concerning the history of a PIP joint fracture, in- cluding time to presentation, mech- anism of injury, and occurrence of subluxation or dislocation, are im- portant. The direction of any initial displacement should be noted. Examination of the digit begins with inspection for deformity, swelling, or laceration. Local ten- derness of the affected digit, as well as injury to the soft-tissue structures of adjacent digits, should be evalu- ated. If a reduction maneuver has been previously performed, radio- graphs should be reviewed before testing range of motion. If the joint is dislocated or subluxated, reduc- tion is attempted under digital block anesthesia, after which active and passive range of motion are assessed. Fluoroscopic examination is frequently helpful in evaluating fracture-dislocations that are re- ducible. The position at which sub- luxation occurs is recorded. A true lateral radiograph with the joint in full extension confirms postreduc- tion stability. If initial closed reduc- tion is not successful, the surgeon must choose among the various other treatment options. If initial closed reduction of a dislocation without a fracture is not successful, a complex dislocation is likely to be present, requiring open reduction. Pathology Fractures of the PIP joint can be divided into injuries with and without joint instability. Treatment goals for fractures without joint Volar view Lateral view Figure 1 The bicondylar configuration of the PIP joint provides intrinsic stability. (Adapted with permission from Bowers WH: The anatomy of the interphalangeal joints, in Bowers WH [ed]: The Inter- phalangeal Joints. New York: Churchill Livingstone, 1987, p 3.) Figure 2 Sagittal view of the PIP joint illustrates the relative positions of the central slip, volar plate, collateral ligament, and accessory collateral ligament. (Adapted with permis- sion from Bowers WH: The anatomy of the interphalangeal joints, in Bowers WH [ed]: The Interphalangeal Joints. New York: Churchill Livingstone, 1987, p 11.) Proper collateral ligament Central slip Recess Middle phalangeal attachment of central 80% of volar plate Accessory collateral ligament Proximal lateral checkrein Philip E. Blazar, MD, and David R. Steinberg, MD Vol 8, No 6, November/December 2000 385 subluxation are similar to those for other articular fractures: reduction and stability of the fracture frag- ments, restoration of articular con- gruity, and joint mobilization. There are no specific data relating the amount of displacement of the articular surface to clinical out- come. Patients must be specifically informed by the surgeon regarding the risks and benefits of surgical intervention for fractures with small amounts of displacement. Fractures accompanied by joint subluxation are more difficult to manage. Joint subluxation or dislo- cation must be reduced and must not be allowed to recur during treatment. Maintenance of joint reduction is a primary goal of treat- ment and may dictate postinjury management, such as limitation of early mobilization of the digit. Other factors must be considered in determining treatment in addition to the presence or absence of sub- luxation. Fractures of the PIP joint are frequently complicated by open wounds and may be accompanied by injury to tendons, nerves, blood vessels, or skin. The complexity of the injury to the bone and adjacent soft-tissue structures must be con- sidered when selecting from among the various treatment options. For example, a substantial soft-tissue injury may limit the options advis- able for a given fracture pattern. Proximal Phalanx Fractures Fractures of the articular surface of the proximal phalanx can involve one or both condyles. The mecha- nism of injury is usually a direct blow and an axial load to the tip of the digit, as from impact by a ball in a sporting activity. The digit must be carefully inspected for the pres- ence of rotational deformity. Dis- placement may be seen on an ante- roposterior radiograph, but can be confirmed only with a true lateral radiograph of the digit when the two condyles are not superimposed. Oblique radiographs may be neces- sary to observe displacement not apparent on anteroposterior and lat- eral films. Unicondylar injuries are poten- tially unstable even when nondis- placed. The treatment options for these fractures are (1) immobiliza- tion, with frequent clinical and radiographic observation, and (2) operative stabilization with percu- taneous pinning and early mobi- lization. Displaced or malrotated injuries require reduction and stabi- lization, which is often possible with indirect reduction and percu- taneous pinning. If open reduction is required, soft-tissue attachments must be maintained to preserve vascular supply. At least two im- plants are recommended to obtain rotational stability of the fracture. Screw fixation for open reduction and internal fixation (ORIF) is pref- erable, as it can provide sufficient stability for early mobilization if the quality and size of the condylar fragment are adequate. The combi- nation of one screw and one Kirsch- ner wire (K-wire) is acceptable if placement of two screws is techni- cally difficult. Although screws may provide more stability, place- ment of screws is technically more challenging than insertion of K- wires. Screw fixation requires more soft-tissue stripping and may result in overcompression of a commi- nuted fracture. Surgical treatment predictably leads to union. However, some loss of motion is common. Weiss and Hastings 6 reported on 38 fractures treated by either operative or non- operative methods, with only a mean active range of PIP joint mo- tion of 71 degrees at a mean follow- up interval of 3 years. Bicondylar fractures are usually unstable injuries and may be associ- ated with substantial comminution of the articular surface. Closed re- duction and pinning are occasionally acceptable, but open reduction is commonly required to reduce the condyles. The choice of a dorsal or midlateral approach is dependent on the plan for fixation. The dorsal approach affords better exposure of both condyles but necessitates more dissection of the extensor mechanism and therefore increases the likeli- hood of adhesions. A midlateral incision is technically more demand- ing and places the digital neurovas- cular bundle at greater risk. It pro- vides better exposure for lateral hardware placement and is not un- der any tension during postsurgical rehabilitation. Mini-condylar blade- plate fixation is not commonly re- quired but may be utilized. This technique provides adequate stabil- ity for early joint mobilization but requires more surgical exposure and technical precision. The rate of com- plications associated with plate and/or screw fixation in the digits (e.g., stiffness, delayed union, and infection) is substantial. 5 Fixation with K-wires and/or interfragmen- tary screws can be augmented with a mini–external fixator. External fixa- tion devices are rarely used alone for proximal phalanx fractures but can function as adjunctive fixation if the surgeon remains concerned about joint or fracture stability after inter- nal fixation. Middle Phalanx Fractures Intra-articular fractures of the mid- dle phalanx require careful atten- tion because apparently benign injuries can lead to joint instability and severe functional problems. These injuries have been grouped according to the anatomic location of the fracture and the presence of joint instability. The common frac- ture patterns are those affecting the dorsal lip, the palmar lip, or both surfaces (pilon type). By definition, Proximal Interphalangeal Joint Fractures Journal of the American Academy of Orthopaedic Surgeons 386 fracture-dislocations include a liga- mentous injury or ligamentous insufficiency resulting from the fracture. Dorsal Lip Fractures of the dorsal lip of the middle phalanx occur as a result of hyperflexion of the PIP joint. Usu- ally 25% of the articular surface or less is involved. Characteristically, comminution of the articular surface is limited, and articular depression and joint instability are infrequent. A dorsal lip fracture can be an avul- sion of the insertion of the central slip of the extensor mechanism. If the fracture is nondisplaced, the joint surface is congruent, and the joint is reduced, the digit can be splinted in extension. Active motion of the distal interphalangeal (DIP) joint is permitted. Gentle mobiliza- tion of the PIP joint can begin 3 to 4 weeks after injury; however, splint- ing should be continued for 6 to 8 weeks after injury. If the digit lacks motion at 8 weeks, more aggressive modalities to regain motion may begin (e.g., dynamic flexion splint- ing or progressive static splinting). Displaced fractures require op- erative intervention. The central slip is reattached to avoid a bou- tonnière deformity. 7 The goal is stable fixation for immediate mobi- lization. These injuries are typical- ly approached dorsally, and the options include mini-screw fixation if the fragment is adequate in size and tension-band or K-wire fixa- tion for smaller fragments. Palmar Lip Fractures of the palmar lip are more common than injuries to the dorsal lip and may be caused by either hyperextension or axial load- ing. Radiographically, injuries resulting from either of these mech- anisms can be deceptively similar. Hyperextension injuries are avul- sions of the joint surface by the volar plate, which usually involve less than 30% of the joint surface and have little articular comminu- tion. In contrast, injuries from lon- gitudinal impaction are character- ized by articular comminution, which may involve the entire artic- ular surface. Treatment of palmar lip fractures can be one of the most challenging problems faced by orthopaedic sur- geons. These injuries frequently result in unstable joints with persis- tent joint subluxation, and delay in diagnosis is associated with a poor outcome. There is a direct relation- ship between the amount of the surface that has been fractured and the stability of the joint. Fractures involving 30% or less of the articu- lar surface are typically stable after reduction. Fractures involving 50% or more of the articular surface tend to be unstable. These numbers are only guidelines, however, and sta- bility must be tested after reduction. The primary goal of treatment is to restore joint stability; restoration of the articular surface is some- times difficult and is less critical to the outcome. 8-10 Imperfect reduc- tion of the articular surface has a less significant effect on functional outcome than a delay in achieving a stable reduction. It is important to check for subtle signs of instability on postreduction lateral radiographs of the digit. A true lateral radiograph should show a congruent joint space with two parallel surfaces. Divergence of the posterior articular surfaces from the central portion of the joint (a “V” sign) indicates incomplete re- duction (Fig. 3). 11 A small volar-plate avulsion may present acutely or subacutely, with the patient complaining of persistent stiffness and swelling weeks or months after a “jammed” finger. Mechanically, the joint is typically stable; however, patients are likely to experience some swelling and stiffness for as long as 6 months. For comfort, the digit may be splinted in 20 degrees of flexion, but for no more than 7 days. Active motion should be started early: buddy taping for several weeks allows active motion as well as protection and support by the adjacent finger. This tech- nique is particularly helpful in ath- letes, who are likely to subject the injured digit to a second episode of trauma. Overtreating these injuries with prolonged splinting may result in a stiff joint. Patients with difficulty regaining motion may need supervised therapy for pas- sive manipulation, edema control, and dynamic splinting. In the unstable joint, dorsal sub- luxation typically occurs at less than full extension and is usually managed with an extension-block splint set at 10 to 20 degrees less extension than the stable point. The patient is encouraged to active- ly flex the finger in the splint. There are many types of extension- block splints, 12 which a therapist can fabricate from heat-sensitive plastic. The plastic can be reheated and molded to the degree of flexion required over the course of treat- ment. The allowed range of mo- tion is increased to full extension over 3 to 8 weeks, depending on the stability of the injury. Frequent Figure 3 Light 11 described a dorsal “V” sign on a lateral radiograph that indicates PIP joint subluxation, illustrating that the articular surfaces are neither congruent nor parallel. Subluxated Normal Philip E. Blazar, MD, and David R. Steinberg, MD Vol 8, No 6, November/December 2000 387 clinical and radiographic follow-up is required for the first 3 weeks to assess whether subluxation has re- curred. As the size of the volar fragment increases, the degree of instability usually increases. If the entire col- lateral ligament is attached to the palmar fragment, the joint will be unstable. The criteria for extension- block splinting utilized with smaller fragments can be employed. The practical use of extension-block splinting is limited by the degree of flexion required to maintain reduc- tion. If flexion beyond 60 degrees is required, the active arc of motion is minimal, and other options should be considered. For unstable fractures, immobi- lization in a reduced position with external support or with a transar- ticular K-wire can be used. How- ever, immobilization is likely to lead to permanent joint contrac- ture, especially if maintained for more than 3 weeks. Extension- block pinning with K-wires (Fig. 4) requires less postoperative supervi- sion to maintain reduction than extension-block splinting. The joint is reduced, and a K-wire is inserted percutaneously into the head of the proximal phalanx, parallel to the shaft. The wire is placed with the joint in full flexion to prevent re- striction of flexion by the extensor mechanism (which is transfixed by the wire). 13 Early active motion is encouraged. If the joint can be reduced but not practically maintained by closed means, several open tech- niques can be used to maintain reduction. If the volar fragment is not comminuted, open reduction and fixation with one or more K- wires or mini-screws or a tension band is possible. If the fragments are comminuted, open reduction can be technically challenging or impractical because of inability to achieve adequate fixation sufficient for early motion. A number of techniques use ligamentotaxis to maintain general joint reduction. These methods utilize traction by means of a pin placed percuta- neously through the middle pha- lanx or a hinged external fixation device. Traction apparatuses have been reported by several authors. 8 Complications reported with trac- tion techniques include pin-track infection, pin loosening, residual joint depression, loss of PIP and DIP joint motion, and pain. Agee 14 has published a method of maintaining reduction by pro- ducing a force couple with three K- wires and a rubber band. The force couple is arranged to pull the head of the proximal phalanx dorsally and the base of the middle phalanx volarly to maintain joint reduction (Fig. 5). This technique requires a stable dorsal shelf of intact middle phalanx to resist axial displacement. The method has been criticized for being technically difficult. 15 Com- plications include resubluxation, loss of DIP and PIP joint motion, and pyarthrosis. Use of hinged external-fixation devices mobilizes the injured joint while maintaining reduction. These devices are designed to approxi- mate PIP joint motion about a point in the head of the proximal phalanx and can be employed with or with- out internal fixation. This tech- nique allows early mobilization while maintaining joint and frac- ture reduction through ligamento- taxis. There are currently few pub- lications that describe indications, outcome, and complications in de- tail. Complications include pin- track drainage, pin loosening, deep infection, recurrent subluxation, and arthritic changes. 9,16,17 Fractures of the volar lip that in- volve more than 50% of the articular surface are almost universally un- stable and require an open proce- dure to recreate volar support and prevent redislocation. Although traction or external fixation can be used to maintain joint reduction, these techniques rarely achieve reduction of the articular surface. Because of the degree of comminu- tion and instability, a combination of ORIF and external fixation or Figure 4 A, Radiograph of a patient with a dorsal fracture-subluxation of the PIP joint involving 40% of the articular surface. B, Intraoperative radiograph shows extension-block pin in place and reduction of the PIP joint. A B Proximal Interphalangeal Joint Fractures Journal of the American Academy of Orthopaedic Surgeons 388 traction may be required. The indi- cations for ORIF include involve- ment of 25% or more of the joint surface, displacement of the articu- lar surface, and joint instability. 18 The approach is through a volar zigzag incision, opening the flexor tendon sheath between the A2 and A4 pulleys. Exposure of the frac- ture may require release of the col- lateral ligaments and volar plate. The joint can be hyperextended to improve visualization of the articu- lar surface. Depressed articular fragments are elevated to restore the articular surface. Bone grafting of defects under impacted fragments will increase stability. Screw fixa- tion is used for large fragments, and K-wire or cerclage fixation is used for smaller comminuted fractures. Although ORIF is the best option for restoring the articular surface, high complication rates have been reported. In the only published series comparing ORIF with trac- tion or immobilization, 19 ORIF did not result in superior motion or de- crease arthritic changes. Reported complications include pyarthrosis, loss of fixation and reduction, arthritic changes, pain, DIP and PIP joint contracture, and loss of grip strength. Volar-plate arthroplasty as de- scribed by Eaton is also an option if the articular surface cannot be re- paired. 20 The indications for this procedure differ among surgeons. Some authors primarily use the tech- nique to salvage late dislocations; others prefer this procedure for many acute fracture-dislocations. 10,21 The joint is exposed by using the approach described for ORIF. The volar plate is incised along its lateral margins, freeing it from the collat- eral ligaments. The distal end of the volar plate is freed from any bone fragments. A shallow transverse trough is created across the entire middle phalanx at or near the junc- ture between the intact articular sur- face and the fracture defect. The trough must be symmetrical in the coronal plane. The volar plate is ad- vanced into the defect and held in place with sutures or pull-out wires through bone. These can be secured over a dorsal button or on the dor- sum of the middle phalanx beneath the extensor mechanism. The ad- vanced volar plate resurfaces the palmar portion of the middle pha- lanx and assists in joint stabilization (Fig. 6). A congruent reduction must be achieved; a K-wire is frequently placed with the joint in slight flexion to maintain the reduction for several weeks. The most common complication is a flexion contracture of the PIP joint. Other complications of this procedure include redisplacement, angular deformity, and loss of motion at the PIP and/or DIP joint. Dorsal and Palmar Lip Injuries caused by axial loading, which involve both the palmar and dorsal cortices, have been referred to as pilon-type fractures. The artic- ular surface has been described as exploding from the axial forces, causing these injuries to exhibit the greatest amount of joint disruption. These fractures include components of central depression with com- minution and displacement of the articular surface, as well as the volar and dorsal cortices. Techniques for treatment of these injuries include immobilization, traction, external fixation, and ORIF. It is difficult to compare the results of treatment from one published series to another because the fracture classifications and indications are not uniform. Because of the technical complex- ity and poor outcomes associated with ORIF, many surgeons prefer either traction or external fixation. The joint surface is not exposed, and reduction is achieved through liga- mentotaxis. Reduction of the articu- lar surface is always imperfect. 22 Traction is exerted by attaching a rubber band to a pin placed in the middle phalanx distal to the articu- lar surface (Fig. 7). The rubber band is connected to an external splint that is fabricated to allow motion. Early motion reduces contracture of the soft-tissue envelope. 23,24 Trac- tion is maintained for about 6 weeks. The joint is initially mobi- lized within a limited range, which is based on fluoroscopic examina- tion of joint stability. After 2 to 3 weeks, the range is increased. Proponents of this technique emphasize the articular remodeling that can occur with passive motion. Therapy is often required after re- moval of the traction splint; how- ever, substantial motion is gained after removal of the external de- vice. Schenck 8 reported an active A B Figure 5 A, Representation of the Agee force-couple technique. The force couple is con- structed from three K-wires and a rubber band. B, Use of the Agee force-couple technique in the treatment of a subacute fracture-dislocation. Rubber band Middle phalanx Proximal phalanx Smooth 0.045-inch K-wires Tape Threaded 0.062-inch K-wire Philip E. Blazar, MD, and David R. Steinberg, MD Vol 8, No 6, November/December 2000 389 range of motion of 50 degrees at splint removal, with 50% of pa- tients having active motion of 40 degrees or less at traction removal. At long-term follow-up, the aver- age arc of active motion was 87 de- grees. Articular impaction cannot be reduced by traction; therefore, some authors have questioned whether results will deteriorate over the long term. Stern et al 19 compared different treatments, including immobiliza- tion, traction, and ORIF. All three methods resulted in some loss of DIP and PIP joint motion. Extension- block splinting led to loss of motion and a high likelihood of symptom- atic arthritis. A higher rate of com- plications was associated with ORIF, including the inability to achieve adequate fixation to begin early mobilization in several cases. The authors concluded that skeletal traction provided motion compara- ble to that obtained with ORIF with a lower complication rate. Regardless of the treatment selected, careful follow-up and su- pervision of rehabilitation are essen- tial. Radiographs should be ob- tained at least weekly for several weeks, as early loss of reduction can occur with all methods, particularly those utilizing early motion. Recur- rent subluxation is the result of in- adequate treatment or poor patient compliance and should be treated operatively when discovered, as the results of salvage surgery are ac- ceptable but worse than the results of treatment of the acute injury. Rehabilitation Loss of finger motion can be ex- pected if mobilization is not insti- tuted early; however, some loss will occur regardless of treatment and rehabilitation. The goal of sur- gical or nonsurgical treatment is to initiate motion as soon as stability can be verified. In adults, immobi- lization for a period of 4 weeks or longer is likely to produce a sub- stantial contracture, which will be difficult to overcome with rehabili- tation. Rehabilitation must be tai- lored to the individual and the injury. In general, however, active motion is usually initiated early, while use of active assisted and passive modalities is delayed until the fracture has healed. In fractures that have been treat- ed in a closed manner, active mo- tion is initiated by 3 to 4 weeks after injury, but splinting continues until fracture healing has occurred. Typi- cally, healing occurs by 6 weeks. Passive motion and dynamic splint- ing may begin around that time if indicated. The time course is similar for fractures treated with closed re- duction and percutaneous pinning. In some instances, active motion is initiated with the pins in place. Pin sites must be carefully fol- lowed, as pin complications may be higher if the digit is mobilized. Figure 6 A, Volar-plate arthroplasty technique. B, Radiograph shows a chronic fracture- dislocation of the PIP joint. C, Radiograph obtained after treatment with volar-plate arthroplasty and a hinged external fixator. Volar view Lateral view Volar plate Volar plate Pull-out suture button Middle phalanx Proximal phalanx Figure 7 Range of motion 4 weeks after application of a traction device. A B C Proximal Interphalangeal Joint Fractures Journal of the American Academy of Orthopaedic Surgeons 390 In the setting of stable fixation, the digit is protected with an external splint, but active range of motion is begun within 1 week. Passive mo- tion and dynamic splinting are de- layed until fracture healing, which lags several weeks behind healing of fractures treated in a closed manner. With an articulated fixator, ac- tive or passive motion may be initi- ated within the first week. The fix- ator is removed at 4 to 6 weeks, and rehabilitation is progressed according to fracture healing and joint stability. Strengthening mo- dalities are usually limited or avoided until solid union has occurred and range of motion has been regained. Summary Early recognition of joint instability is essential for adequate treatment of injuries of the PIP joint. These in- juries are often misdiagnosed as being merely a “jammed finger,” re- sulting in treatment delays. Reduc- tion of the joint is the primary goal of treatment, followed by recon- struction of the articular surface, if technically feasible. The surgeon should be facile with a number of techniques, which need to be care- fully selected for the individual patient and injury. In general, treat- ment options that require more than 3 to 4 weeks of immobilization should be avoided. Loss of some motion should be expected, especi- ally in the case of more severe in- juries; however, functional motion can often be achieved. 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