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Vol 8, No 2, March/April 2000 111 The longitudinal bones of the hand form a jointed system of levers between the forces of the flexor and extensor tendons. Fractures of the metacarpals and phalanges can disrupt this sophis- ticated mechanism, leading to impairment of hand function. Thus, management of these fractures should concentrate on restor- ing skeletal stability and hand function. The optimal treatment for a specific injury is determined on the basis of the extent of disruption of the bone and surrounding soft tissues. Most metacarpal and phalangeal fractures can be treated adequately by immobilization or protective splinting. Oper- ative treatment is indicated for irreducible or unstable fractures. Proper incision placement, atrau- matic soft-tissue handling, and adequate fixation will optimize the outcome. Basic Science Anatomy The metacarpals are concave on the palmar surface and form the longitudinal and transverse arches of the hand. 1 The index- and long- finger metacarpal articulations with the trapezoid and capitate allow only limited motion. In contrast, the ring- and small-finger metacarpal articulations with the hamate permit considerable flexion- extension and slight rotation. This variation in carpometacarpal motion affects the amount of angulation that can be accepted in metacarpal fractures. As a general rule, the hand can accommodate 10 to 15 degrees of dorsal angulation more than the available carpometacarpal joint motion of the involved digit. 2 Therefore, little angulation (10 to 15 degrees) can be accepted in metacarpal fractures in the index and long fingers, whereas 30 to 35 degrees is acceptable in the ring finger and up to 50 degrees in the small finger. The three palmar and four dorsal interossei arise from the metacarpal shafts and, along with the lumbricals, are the prime metacar- pophalangeal (MCP) joint flexors. 3,4 The palmar interossei originate as a single muscle belly from the palmar two thirds of the metacarpal shaft and insert on the anterolateral base of the proximal phalanx and on the extensor mechanism, forming part of the lateral band. The dorsal interossei originate as two muscular bellies on adjacent metacarpals and likewise insert on the anterolateral base of the proximal phalanx and on the extensor mechanism opposite the palmar Dr. Kozin is Associate Professor, Department of Orthopaedic Surgery, Temple University, Philadelphia; and Attending Hand Surgeon, Shriners Hospital for Children, Philadelphia. Dr. Thoder is Associate Professor, Department of Orthopaedic Surgery, Temple University; and Attending Hand Surgeon, Shriners Hospital for Children. Dr. Lieberman is Chief Resident, Department of Orthopaedic Surgery, Temple University. Reprint requests: Dr. Kozin, Department of Orthopaedic Surgery, Temple University, Broad and Ontario Streets, Philadelphia, PA 19141. Copyright 2000 by the American Academy of Orthopaedic Surgeons. Abstract Diaphyseal fractures of the metacarpals and phalanges are common injuries that can lead to impairment of hand function. The fracture pattern and soft-tissue injury vary with the mechanism of injury. The imbalance of the flexor and extensor forces created by displaced fractures will often produce a secondary angulatory deformity. Nonoperative treatment is indicated for reducible and stable fracture configurations. Irreducible or unstable fracture patterns require open or closed reduction and fixation. Reduction must be assessed in flexion and extension to ensure correct rotatory alignment. Fracture fixation can be achieved with the use of Kirschner wires, interfragmentary screws, or plates. The outcome after surgery is greatly influenced by the condition of the surrounding soft tissues; therefore, surgical trauma should be minimized to optimize the result. J Am Acad Orthop Surg 2000;8:111-121 Operative Treatment of Metacarpal and Phalangeal Shaft Fractures Scott H. Kozin, MD, Joseph J. Thoder, MD, and Glenn Lieberman, MD interossei insertions. The intrinsic muscles and extrinsic flexor tendons create deforming forces on metacarpal shaft fractures, result- ing in apex dorsal angulation. 1 At the level of the MCP joint, the extensor hood is formed by the coa- lescence of the extensor digitorum communis tendon and the intrinsic muscle tendons. 3,4 The interossei and lumbrical muscles travel volar to the MCP joint to join the extensor hood. The central slip attaches to the dorsal base of the middle phalangeal base and extends the proximal interphalangeal joint. On the volar side, the flexor digitorum superficialis divides into two halves at the level of the MCP joint and rotates 90 degrees to allow the flex- or digitorum profundus to navigate toward the distal phalanx. The flexor digitorum superficialis un- dergoes a second 90-degree rotation, inserting into a ridge along the middle two thirds of the volar surface of the middle phalanx. 3,4 Proximal phalangeal fractures will usually angulate with an apex volar deformity. 1 The proximal fragment is flexed by the interossei insertions into the proximal phalangeal base, and the distal fragment is pulled into hyperextension by the central slip acting on the base of the middle phalanx. Mid- dle phalangeal fractures are less predictable with regard to angulation, as extensor and flexor forces traverse the midportion of the middle phalanx. A distal-third fracture tends to angulate with an apex volar deformity from the action of the flexor digitorum superficialis on the proximal fragment. A proximal- third fracture usually angulates with an apex dorsal deformity as the flexor digitorum superficialis flexes the distal fragment, and the central slip extends the proximal fragment. Distal phalangeal fractures are usually comminuted tuft or diaphyseal fractures secondary to a crush injury. Because both the extensor and flexor tendons insert on the distal phalangeal base, they usually do not cause displacement. In addition, the nail plate acts as a stent to preserve alignment. Mechanism of Injury The mechanism of injury will influence the presenting fracture pattern and finger deformity. The direction of fracture angulation is determined by the imbalance across the fracture site between flexor and extensor forces. A direct blow to the dorsum of the digit will yield a transverse fracture and, depending on the magnitude of the impact, variable degrees of comminution. 5 A combination of bending and axial compression will produce a comminuted fracture with an associated butterfly fragment. A twisting injury will cause a spiral fracture with the fracture line oriented 45 degrees to the shaft of the bone. 6 A combination of torque and axial load will produce a short oblique fracture with variable comminution. Fracture Healing Fracture healing can be altered by the method of fracture fixation utilized. Closed reduction and pin- ning maintains the fracture hema- toma and envelope, which has a positive influence on fracture healing. In contrast, open reduction and internal fixation disrupts this fracture milieu, and rigid internal fixation reduces micromotion and strain. Primary bone healing or contact healing without the formation of intermediary callus must occur to achieve union after rigid fixation. 7 Rigid fixation by plate application can also cause stress-shielding of the underlying bone and may result in late resorption and weak- ening of the bone. Furthermore, the direct placement of plates onto bone disrupts the vascular status by limiting vascular access to the periosteum and impeding blood supply from the medullary cavity to the periosteum, 5 leading to the development of a region of porotic bone beneath the plate. In an effort to counter this process, plates with less direct bone contact (limited contact) and a lower modulus of elasticity (e.g., those made of titanium) have been developed. Implant Biomechanics There are numerous implants and techniques available for fixation of metacarpal and phalangeal fractures. Proficiency with several techniques allows the surgeon to tailor the fixation to the fracture pattern. Fixation of hand fractures requires small implants that provide adequate stability but minimize interference with the surrounding soft tissues. Available implants include Kirschner wires, wire sutures (cer- clage or interosseous wires, tension- band fixation), screws, plates, and absorbable implants. The type of implant employed depends on the fracture pattern, the soft-tissue injury, and surgeon preference. Stainless-steel Kirschner wires utilized for diaphyseal metacarpal fracture fixation range in diameter from 0.9 to 1.1 mm and have different tip profiles (trocar- or diamond- shaped). Kirschner wires are inserted with a power drill and can be used for either provisional or defini- tive fixation. The stability of the fracture fixation is dependent on the diameter of the Kirschner wire and the configuration of wire placement. For transverse fractures, crossed wires produce the most resistance to torsion and distraction. 8 Crossed and longitudinal configurations provide comparable stability against bending. For oblique fractures, bending, torsion, and distraction are best resisted by a pin placed perpendicular to the fracture; compressive loading is best resisted by a wire placed perpendicular to the shaft. 5 Therefore, using multiple wires in Metacarpal and Phalangeal Shaft Fractures Journal of the American Academy of Orthopaedic Surgeons 112 different orientations is preferred for oblique or spiral fractures. The primary function of a screw is to compress; the torque applied for screw insertion is converted to compression between two fracture fragments or the plate and bone. The screw specifications include diameter, pitch, and head size. 5 The major, or outer, diameter gen- erally ranges between 1.1 and 2.7 mm for hand surgery (depending on bone diameter) and directly influences pull-out strength. The inner, or root, diameter is the shank size, which directly affects the ten- sile strength, the bending strength, and the resistance to breakage. Pitch is the distance between the screw threads, which determines the rate of advancement during insertion. A standard cortical screw has a pitch of 0.8 to 1.2 threads per millimeter. 9 The head size varies with the screw diameter. The contact load (force/area) exerted by the head can be dispersed by counter- sinking the head or adding a washer to increase the contact area. The standard technique of screw insertion is to drill, measure, tap, and then insert the screw. Lag screws can achieve more compression across the fracture site if a hole is drilled in the proximal cortex equal in diameter to the outer diameter of the screw. 9 This gliding hole eliminates thread purchase on the near cortex and allows the screw to engage only the far cortex during insertion. Lag-screw placement considerably increases interfragmentary compression; insertion of the screw perpendicular to the fracture plane is best. 5,9 However, this screw orientation provides limited stability to loading along the axis of the bone. Therefore, multiple lag screws should be used in orientations perpendicular to both the fracture and the shaft. Self-tapping screws with a fluted tip cut an advancing thread path through the bone during insertion. Although this design eliminates pretapping, the cutting tip provides minimal hold and must protrude through the cortex to allow the trailing threads to gain purchase. Failure to place the flute through the cortex will decrease the pull-out strength. 5 There are numerous available plate configurations for metacarpal and phalangeal fractures, with plate thicknesses ranging from 1.0 to 2.7 mm. Lower-profile plates minimize interference with the soft tissue but sacrifice plate strength, as the bending strength of a plate is proportional to the cube of its thickness and inversely proportional to the cube of its length. 9 Plate length is selected on the basis of the amount of cortical purchase necessary to achieve stability. Four cortices on each side of a metacarpal or phalangeal diaphyseal fracture is the goal for plate fixation. The plate design can be flat or tubular. Dynamic compression can be achieved by eccentric screw placement and will increase fracture site compression and the rigidity of the fixation. The amount of compression achieved with a plate is considerably less than that achieved with a lag screw. Plates are manufactured from stainless steel, titanium, or a titanium alloy. Titanium has a lower modulus of elasticity (i.e., decreased stiffness), which diminishes the stress- shielding from plate application. Diagnostic Techniques The hand and fingers should be examined for clinical signs of trauma, including swelling and ecchymosis. Areas of tenderness and crepitation should be palpated. Loss of digital length and loss of normal knuckle contour indicate fracture shortening or angulation. Of great importance, the rotational alignment of the digits should be assessed with the fingers extended and flexed. The phalanges should be parallel during extension and point toward the scaphoid tubercle when flexed. Finger extension may mask rotational malalignment because of the normal divergence of the fingers (Fig. 1). Subtle overlap may vary from individual to individual, and comparison to the contralateral side is invaluable. In an uncooperative patient, alignment can be evaluated by generating finger motion through tenodesis involving passive flexion and extension of the wrist. Standard radiographs, including posteroanterior (PA), lateral, and oblique views, are sufficient to eval- uate the vast majority of diaphyseal fractures. Advanced imaging stud- ies, such as computed tomography and magnetic resonance imaging, are not usually indicated for these fractures. Classification and Treatment Phalangeal and metacarpal shaft fractures can be classified by several characteristics. Classification crite- ria include the fracture pattern (transverse, oblique, spiral, or comminuted), fracture location (head, Scott H. Kozin, MD, et al Vol 8, No 2, March/April 2000 113 Figure 1 Active finger flexion produced digital overlap indicative of malrotation in a 45-year-old man with a spiral fracture of the proximal phalanx of the ring finger. Alignment appeared normal when fingers were extended. neck, shaft, or base), and the extent of soft-tissue and/or bone contamination (open or closed). An important factor determining management is whether a fracture is stable or unstable. The amount of initial fracture displacement is an indicator of fracture stability, as considerable separation of the fracture fragments indicates extensive periosteal disruption. The primary indication for fixation of phalangeal and metacarpal shaft fractures is to provide stability to an unstable fracture. Additional indications for fixation include irreducible fractures, open fractures, multiple fractures, fractures with bone loss, and fractures associated with tendon lacerations. 10-12 Distal Phalangeal Fractures Distal phalangeal diaphyseal fractures rarely require operative fixation, except those that are extremely displaced and unstable. Retrograde percutaneous Kirschner-wire fixation is the preferred internal fixation technique. A mini-fluoroscopic unit can aid in wire placement. Middle and Proximal Phalangeal Fractures Transverse diaphyseal fractures of the middle and proximal phalanges that are nondisplaced and stable do not require fixation. Immobilization of the affected digit and at least one adjacent digit in the safe position (70 to 90 degrees of MCP joint flexion with the interphalangeal joints in extension) for 1 to 3 weeks, followed by protected motion (buddy strap- ping) until clinical union, will yield excellent results. Displaced transverse fractures that are unstable after reduction should be treated with closed reduction and percutaneous fixation. 10 The distal fragment is reduced onto the proximal fragment by traction and manipulation. Kirschner wires (1.0 to 1.1 mm in diameter) can be inserted in a crossed or longitudinal configuration in an antegrade or a retrograde direction. For middle phalanx fractures, an extra-articular approach through the base of the phalanx is preferred. Proximal phalanx fractures can be secured with either an extra-articular approach, antegrade through a flexed MCP joint, or with a retrograde approach through a flexed proximal interphalangeal joint. 13 To protect the soft tissue and increase the accuracy of wire placement, a 14-gauge hypodermic needle can be used as a drill guide for wire insertion. Because Kirsch- ner wires have no compressive ability, the fracture must be ana- tomically reduced before insertion of the wire for best results. Manual compression is applied across the fracture site during wire insertion to prevent displacement. If the fracture cannot be adequately reduced by closed means (i.e., angulation less than 10 degrees, shortening less than 2 mm, bone apposition greater than 50%, and no malrotation), open reduction and internal fixation is recommended via a dorsal or midaxial approach (Fig. 2). The dorsal exposure requires mobilization of the extensor mechanism over the middle phalanx or longitudinal split- ting of the extensor tendon over the Metacarpal and Phalangeal Shaft Fractures Journal of the American Academy of Orthopaedic Surgeons 114 A B C D Figure 2 Images of a 60-year-old man who caught his right index finger in a crossbow while hunting. A, Posteroanterior radiograph shows a displaced comminuted transverse midshaft fracture. B, Lateral radiograph shows apex volar angulation. C, Postoperative PA film obtained after open reduction and internal fixation with a mini-condylar blade- plate secured on the lateral border. D, Postoperative lateral film shows mild translation at the fracture site. proximal phalanx. The midaxial approach offers better exposure of the medial or lateral aspect of the bone for plate application. The decreased manipulation of the extensor mechanism with the midaxial exposure can reduce postoperative adhesions and scar contracture of the extensor apparatus. 11 Nondisplaced short oblique fractures of the phalanges may appear unstable but can actually be stable because of an intact volar periosteal sleeve. Immobilization alone, as for a stable transverse fracture, is appropriate; however, the fracture must be examined on a weekly basis for the first 3 weeks to be sure it remains stable. Short oblique fractures that are displaced or malrotated are inherently unstable and require fixation. Closed reduction and fixation with two or more percutaneous Kirschner wires provides adequate stability with minimal additional soft-tissue trauma. 10 The wires should be oriented perpendicular to both the fracture line and the shaft to resist shear and torsional forces. 5 If acceptable reduction cannot be achieved, open reduction is indicated; Kirschner wires, interfragmentary screw fixation, or plate-and-screw fixation can be used. Interfragmentary screw fixation alone is indicated if the fracture length is more than twice the diameter of the bone. A long oblique fracture is defined as a fracture with a length that is at least twice the diameter of the bone at the fracture site. A nondisplaced fracture may retain its position because of an intact periosteal sleeve. When displaced, such a fracture requires fixation with either Kirschner wires or interfragmentary screws (Fig. 3). Closed reduction and percutaneous fixation with two or more Kirschner wires can produce an excellent outcome. A fracture reduction clamp placed percu- taneously and perpendicular to the fracture can provide provisional stability. This Òpin viseÓ can apply compression and prevent displacement during wire insertion. 13 Screws can occasionally be inserted through small stab incisions with the aid of new equipment. Rotational alignment must be carefully checked in extension and flexion. If closed reduction is unsuccessful, or if more rigid fixation is desired (as in cases of multiple fractures), open reduction with interfragmentary lag-screw fixation provides excellent stability (Fig. 4). 11 The interfragmentary screw configuration should include one screw perpendicular to the fracture site for optimal fracture compression and one screw perpendicular to the shaft to resist shear stress at the fracture site. 9 Transverse fractures of the metacarpal shaft are usually dorsally angulated because of the pull of the long flexors and the intrinsic muscles (Fig. 5). 1 As with phalangeal fractures with this pattern, the fracture may be stable after reduction and may therefore be treated suc- cessfully with immobilization. If the reduction is unstable or unac- ceptable (the degree of acceptable angulation is dependent on which metacarpal is fractured), fixation by wires or plates and screws is re- quired. Closed reduction is accomplished by MCP-joint flexion to 90 degrees and reduction of the distal fragment onto the proximal fragment in both the coronal and the sagittal plane. Kirschner wires can be inserted in a crossed pattern or longitudinally as intramedullary fixation to provide stable fixation. Single metacarpal fractures can also be stabilized by pin fixation of the distal fragment to an adjacent intact metacarpal. Special care must be taken with transmetacarpal pin- Scott H. Kozin, MD, et al Vol 8, No 2, March/April 2000 115 A B C D Figure 3 A, PA radiograph of the hand of a 25-year-old man with a malrotated oblique proximal phalanx fracture and a butterfly fragment. B, Lateral x-ray film shows apex volar angulation. C, Postoperative radograph obtained after closed reduction and percutaneous pin fixation with multiple Kirschner wires. D, Lateral x-ray film shows reduction of the fracture with restoration of sagittal alignment. ning to be sure there is no translation or malrotation at the fracture site, as Kirschner-wire insertion can displace the fractured metacarpal toward the adjacent digit. If reduction cannot be accomplished by closed means or if rigid fixation is indicated (e.g., as in a professional athlete), open reduction can be per- formed with fracture fixation by plate and screws. 11,12 Short oblique fractures of the metacarpal shaft can be minimally displaced without malrotation and are amenable to immobilization. Clinical evidence of malrotation and shortening by more than 5 mm are indications for reduction and fixation. The same fixation princi- ples apply as for short oblique phalangeal fractures. Interfragmentary screw fixation of fractures less than twice the diameter of bone should be reinforced with a plate to neu- tralize bending and shear forces. 9 Spiral and long oblique fractures of the metacarpal shaft that are iso- lated to a single metacarpal and initially nondisplaced are typically stable and can be treated with immobilization. If the fracture is displaced, malrotated, or shortened by more than 5 mm, reduction and fixation is indicated (Fig. 6). Closed reduction with Kirschner-wire fixation across the fracture site (transverse, crossed, or longitudinal) or to an intact adjacent metacarpal will provide adequate stability. Prebent and blunted flexible intramedullary rods have been developed to be used like intramedullary Kirschner wires. 14 If closed reduction is unsuccessful, or if more rigid fixation is desired (as in multiple metacarpal fractures), open reduction with interfragmentary screw fixation provides excellent stability. Interfrag- mentary screw fixation alone is adequate if the length of the fracture exceeds twice the diameter of the bone. Shorter fracture lines should be protected from torsional and bending forces by the addition of a plate. The interfragmentary screw configuration should include one screw perpendicular to the fracture site for fracture compression and one screw perpendicular to the shaft to resist shear stress. Two or three 2.0- to 2.7-mm lag screws are typically sufficient. Because of the sus- pensory effect of the intermetacarpal ligaments, fractures of the index- and small-finger metacarpals have less intrinsic stability than those of the middle and ring digits. There- fore, plate fixation of the border metacarpals is recommended in cases of multiple metacarpal fractures to optimize stability. In the operative exposure of metacarpal fractures, incisions should not lie directly over the extensor tendons, to minimize adhesions and the incorporation of fracture, callus, tendon, and skin into a single contiguous scar. Incisions should be placed on the dorsoradial border of the thumb and index-finger metacarpals and on the dorsoulnar border of the small-finger metacarpal. The long- and ring-finger metacarpals are exposed by a longitudinal incision. The extensor tendons are retracted to expose the metacarpal fracture. A junctura tendinum may have to be divided for adequate exposure. Plates should be contoured to accommodate the normal architecture of the bone with a sagittal curve. Straight plates will cause fracture displacement (apex volar angulation) during screw insertion. Fracture With Bone Loss Treatment of a metacarpal or phalangeal fracture with bone loss is challenging. The status of the associated soft-tissue injury is important in planning fracture management. Extensive soft-tissue loss or ex- treme contamination is best treated in a staged manner with repeated debridement, soft-tissue coverage, and restoration of soft-tissue equi- Metacarpal and Phalangeal Shaft Fractures Journal of the American Academy of Orthopaedic Surgeons 116 A B Figure 4 A, PA radiograph of a 20-year-old man with displaced long- and ring-finger spiral proximal phalanx fractures as a result of a motor vehicle accident. B, Postoperative radiograph obtained after open reduction and internal fixation with multiple-lag-screw fixation. librium, followed by delayed bone grafting. Coverage options vary with the extent of injury, from local flaps to more complex regional or free flaps. During this time, bone length is usually maintained by external fixation. 15 In contrast, traumatic bone loss without severe soft-tissue compromise or considerable contamination can be treated by debridement, rigid fixation, and early bone grafting. 12,16 Bone stabi- lization can be accomplished by a variety of methods, with plate-and- screw fixation preferred when adequate bone is available. Postoperative Regimen Postoperative care varies with the patient, the condition of the soft tissues, and the stability of fracture fixation. Reliable patients with rigid fixation, especially screw or plate fixation, can be managed with early active finger motion to pro- mote tendon gliding and decrease tissue edema. Frequent postoperative visits are necessary to monitor the patientÕs progress and to detect problems, especially joint contrac- tures. Fabricated static splints can be used between exercise sessions to rest the injured digit, protect the fracture, and prevent contracture. The splint should position the digit in the safe position with MCP joint flexion and interphalangeal joint extension. Kirschner-wire fixation is less rigid and requires some form of immobilization of the involved digits. Adjacent joints can be exer- cised while safeguarding the fracture through application of manual pressure or a splint. Associated soft-tissue injury requires modification of the postoperative regimen. For example, a fracture with an accompanying extensor tendon injury may be best managed with a dynamic splint that provides controlled finger motion to achieve tendon gliding across the fracture site and minimizes the risk of tendon rupture (Fig. 7). This spe- cialized regimen typically requires a therapist for splint fabrication and oversight of exercises. Results The reported results after fixation of metacarpal and phalangeal fractures are variable. The outcome is based on union, range of motion (ROM), and analysis of complications. Dabezies and Schutte 11 reported ROM greater than 90% in 27 metacarpal and 25 phalangeal fractures treated with plates and screws. Similarly, Ford et al 17 reported total active ROM greater than 220 degrees (normal, 260 degrees) in 20 of 26 (77%) metacarpal fractures treated Scott H. Kozin, MD, et al Vol 8, No 2, March/April 2000 117 A B C D Figure 5 A, Oblique radiograph of the hand of a 20-year-old professional football player shows a transverse metacarpal fracture and apex dorsal angulation. B, PA film reveals slight comminution and ulnar displacement. C, Postoperative PA film obtained after open reduction and internal fixation with a plate-and-screw construct. Four cortices of fixation were obtained to allow early motion. D, Lateral radiograph obtained after plate fixation shows correction of the preoperative angulation and appropriate screw length. by internal fixation. Bosscha and Snellen 18 reported excellent results after screw and/or plate fixation of metacarpal and phalangeal fractures, with 35 of 38 (92%) displaying more than 220 degrees of motion. Less impressive results and considerable complications have been reported by other authors. Pun et al 19 reported that only 26% of phalangeal fractures treated by plate and/or screw fixation achieved ROM more than or equal to 210 degrees. Chen et al 20 reported that 46% of 72 metacarpal and phalangeal fractures treated by internal fixation regained more than 210 degrees of motion. Page and Stern 21 recently reported on 100 metacarpal and phalangeal fractures treated by plate and screw application and noted that 52% obtained ROM greater than or equal to 220 degrees. In addition, one or more complications, including stiffness, nonunion, plate promi- nence, and tendon rupture, occurred in 57% of these fractures. Diwaker and Stothard 22 compared 40 fractures treated nonoperatively with 45 treated surgically. The operative group was further subdivided into two groups on the basis of fracture fixation with miniature screws or Kirschner wires. Although the results are difficult to interpret because of confounding variables, fixation with screws pro- vided better motion, with almost 80% of patients achieving ROM of 210 degrees or more, compared with only 50% treated with Kirschner wires or nonoperatively. Reported results of Kirschner- wire fixation for metacarpal and phalangeal fractures have been fa- vorable. 13,14,23 Gonzalez and Hall 14 reported on intramedullary fixation of 68 metacarpal fractures and 22 phalangeal fractures with the use of an 0.8-mm flexible rod. Of the 68 patients with metacarpal fractures, 66 (97%) regained at least 90 degrees of MCP joint flexion. All 20 patients with proximal phalangeal fractures regained 90 degrees of active MCP joint motion. Green and Anderson 10 reported that 18 of 26 unstable phalangeal fractures regained full ROM within 8 weeks after percutaneous pin fixation. Belsky et al 13 reported on 100 phalangeal fractures treated with percutaneous Kirschner-wire fixation; 61 achieved total active motion greater than 215 degrees, and an Metacarpal and Phalangeal Shaft Fractures Journal of the American Academy of Orthopaedic Surgeons 118 A B C D Figure 6 A, Oblique radiograph shows a displaced long oblique fracture of the ring-finger metacarpal in a 16-year-old high school baseball player. B, PA film demonstrates shortening of the fractured metacarpal. C, PA radiograph obtained after interfragmentary screw fixation to restore anatomic alignment. D, Lateral film reveals correction of the fracture angulation and screw fixation. Figure 7 Dynamic splint with flexion block allows early tendon gliding over the fracture sites while protecting the tendon repair. additional 29 obtained at least 180 degrees of motion. Botte et al 24 reported an 18% pin complication rate in 137 patients who underwent smooth-pin fixation of fractures and dislocations in the hand and wrist. Complications included superficial infection, pin loosening, loss of reduction, pin migration, and neurovascular injury. The difference in results after fixation of metacarpal and phalangeal fractures is best explained by examination of fracture demographics. Open fractures occur with an extensive soft-tissue injury, have associated injuries (nerve, artery, tendon), are caused by a high-energy injury, involve the phalanges rather than the metacarpals, and have a poorer prognosis. Injuries that are isolat- ed, closed, caused by a low-energy injury without bone loss, and involve the metacarpal have a better prognosis with fewer complications. Therefore, the location, extent, and severity of the fracture and soft-tissue injury appear to be more important to outcome than the method of fixation. Complications of Metacarpal and Phalangeal Fractures Complications can occur during surgery or in the postoperative period and can involve the bone or any of the surrounding tissues. Infection is always a concern after fracture fixation; treatment requires early recog- nition, antibiotic therapy, and ag- gressive debridement. Any seques- trum must be removed to eradicate infection. Skeletal reconstruction may have to be delayed until the infection has been eliminated. External fixation is useful to main- tain length after bone debridement. Scarring of the soft tissues can occur in the skin, around tendons, or in joint capsules. Initial treatment is therapy for scar mobilization, tendon gliding, and joint mobilization. Recalcitrant cases may require tenol- ysis and/or joint release to restore motion. The principal osseous complications of metacarpal and phalangeal fractures are nonunion and malunion. Clinical union (i.e., when the fracture becomes stable and pain- less) usually requires 4 to 5 weeks for the metacarpal and 3 to 4 weeks for the phalanx. Clinical union will precede radiographic evidence of healing (visualization of trabeculae crossing the fracture site). Non- unions are uncommon, with an incidence of less than 1%. 25 Predis- posing factors include high-energy injuries, significant soft-tissue dam- age, systemic disease (e.g., malnutri- tion), infection, and poor blood supply to the fracture site. Nonunions of the metacarpals and phalanges can be atrophic or hypertrophic. 7 An atrophic nonunion has little or no callus, which implies an inadequate environment for healing (Fig. 8). Treatment requires alteration of the fracture milieu by curettage of the fibrous tissue, addition of an osteogenic material (e.g., bone graft), and internal fixation to achieve union (Fig. 9). A hypertrophic union has abundant callus, which indicates inadequate immobilization; the optimal treatment is to obtain fracture stability by cast application or fracture fixation, which may not necessitate dis- turbing the fracture site. Malunion is typically character- ized by malrotation, angulation, or Scott H. Kozin, MD, et al Vol 8, No 2, March/April 2000 119 Figure 8 PA radiograph of the hand of a 35-year-old man after treatment of an open fracture of the index metacarpal. The patient had motion and pain at the fracture site, and the x-ray film reveals an atrophic nonunion. A B Figure 9 A, Exposure of nonunion site in preparation for curettage, bone grafting, and internal fixation. B, Internal fixation accomplished with a mini-condylar blade-plate device to achieve skeletal stability. shortening. Malrotation is best assessed by physical examination; the patient makes a fist, and the exam- iner looks for digital overlap (scis- soring) (Fig. 3). Malrotation occurs most frequently with splinting of closed unstable fractures or internal fixation with a single longitudinal Kirschner wire that does not control rotation. Malrotation is treated by a corrective osteotomy, usually at the malunion site. 26 Rotatory malunion of the phalanx can also be corrected by a metacarpal osteotomy to avoid dissection within the finger, thus decreasing the potential for adhesions of the extensor mechanism. For every 1 degree of metacarpal rotation, approximately 0.7 degree of correction occurs in the finger, with the amount of correction limited by the deep transverse metacarpal ligament. 27 Nerve or artery injury can result from the initial trauma or can be the iatrogenic consequence of surgery. Careful incision placement, gentle dissection, and proper placement of fixation devices will decrease the incidence. The sensory nerves along the dorsum of the hand are particularly prone to neu- roma formation and must be retracted gently. Kirschner wires must be inserted with care to avoid piercing or entangling these nerves. In addition, plunging through the far cortex during drilling is necessary to avoid neurovascular injury. Summary Fractures involving the metacarpal and phalangeal shafts occur in multiple patterns (transverse, oblique, spiral, and comminuted). The presenting deformity is influenced by the forces across the fracture site. Treatment options range from immobilization and early motion for stable injuries to surgical intervention with fracture fixation for unstable fractures. Frac- ture pattern, soft-tissue injury, and surgeon preference guide the surgical approach and implant selec- tion. Percutaneous Kirschner-wire insertion and internal fixation with interfragmentary screws or a plate are most commonly utilized. There are advantages and disad- vantages of each technique, and the method selected must be tai- lored to the characteristics of the fracture and individualized to the patient to achieve optimal outcome. Metacarpal and Phalangeal Shaft Fractures Journal of the American Academy of Orthopaedic Surgeons 120 References 1. Flatt AE: Closed and open fractures of the hand: Fundamentals of management. Postgrad Med 1996;39:17-26. 2. Freeland AE, Geissler WB: Plate fixation of metacarpal shaft fractures, in Blair WF, Steyers CM (eds): Techniques in Hand Surgery. Baltimore: Williams & Wilkins, 1996, pp 255-264. 3. Smith RJ: Balance and kinetics of the fingers under normal and pathological conditions. Clin Orthop 1974;104:92-111. 4. Smith RJ: Intrinsic muscles of the fingers: Function, dysfunction, and surgical reconstruction. Instr Course Lect 1975;24:200-220. 5. Tencer AF, Johnson KD, Kyle RF, Fu FH: Biomechanics of fractures and fracture fixation. Instr Course Lect 1993; 42:19-34. 6. Schatzker J, Tile M: The Rationale of Operative Fracture Care. New York: Springer-Verlag, 1987, pp 3-12. 7. Buckwalter JA, Einhorn TA, Bolander ME, Cruess RL: Healing of the muscu- loskeletal tissues, in Rockwood CA Jr, Green DP, Bucholz RW, Heckman JD (eds): Fractures in Adults, 4th ed. Philadelphia: Lippincott-Raven, 1996, vol 1, pp 261-304. 8. Viegas SF, Ferren EL, Self J, Tencer AF: Comparative mechanical properties of various Kirschner wire configurations in transverse and oblique phalangeal fractures. J Hand Surg [Am] 1988;13:246-253. 9. Schatzker J: Screws and plates and their application, in MŸller ME, Allgšwer M, Schneider R, Willenegger H (eds): Manual of Internal Fixation: Techniques Recommended by the AO-ASIF Group, 3rd ed. New York: Springer- Verlag, 1991, pp 179-290. 10. Green DP, Anderson JR: Closed reduction and percutaneous pin fixation of fractured phalanges. J Bone Joint Surg Am 1973;55:1651-1654. 11. Dabezies EJ, Schutte JP: Fixation of metacarpal and phalangeal fractures with miniature plates and screws. J Hand Surg [Am] 1986;11:283-288. 12. Gonzalez MH, McKay W, Hall RF Jr: Low-velocity gunshot wounds of the metacarpal: Treatment by early stable fixation and bone grafting. J Hand Surg [Am] 1993;18:267-270. 13. Belsky MR, Eaton RG, Lane LB: Closed reduction and internal fixation of proximal phalangeal fractures. J Hand Surg [Am] 1984;9:725-729. 14. Gonzalez MH, Hall RF Jr: Intramedul- lary fixation of metacarpal and proximal phalangeal fractures of the hand. Clin Orthop 1996;327:47-54. 15. Peimer CA, Smith RJ, Leffert RD: Distraction-fixation in the primary treatment of metacarpal bone loss. J Hand Surg [Am] 1981;6:111-124. 16. Freeland AE, Jabaley ME, Burkhalter WE, Chaves AM: Delayed primary bone grafting in the hand and wrist after traumatic bone loss. J Hand Surg [Am] 1984;9:22-28. 17. Ford DJ, El-Hadidi S, Lunn PG, Burke FD: Fractures of the metacarpals: Treatment by A.O. screw and plate fixation. J Hand Surg [Br] 1987;12: 34-37. 18. Bosscha K, Snellen JP: Internal fixation of metacarpal and phalangeal fractures with AO minifragment screws and plates: A prospective study. Injury 1993;24:166-168. 19. Pun WK, Chow SP, So YC, et al: Un- stable phalangeal fractures: Treatment by A.O. screw and plate fixation. J Hand Surg [Am] 1991;16:113-117. 20. Chen SHT, Wei FC, Chen HC, Chuang CC, Noordhoff S: Miniature plates

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