Plating of the Distal Radius

Transcription

1 Plating of the Distal Radius Arvind D. Nana, MD, Atul Joshi, MD, and David M. Lichtman, MD Abstract Distal radius fractures are common injuries that can be treated by a variety of methods. Restoration of the distal radius anatomy within established guidelines yields the best short- and long-term results. Guidelines for acceptable reduction are (1) radial shortening <5 mm, (2) radial inclination >15, (3) sagittal tilt on lateral projection between 15 dorsal tilt and 20 volar tilt, (4) intra-articular step-off <2 mm of the radiocarpal joint, and (5) articular incongruity <2 mm of the sigmoid notch of the distal radius. Treatment options range from closed reduction and immobilization to open reduction with plates and screws; options are differentiated based on their ability to reinforce and stabilize the three columns of the distal radius and ulna. Plating allows direct restoration of the anatomy, stable internal fixation, a decreased period of immobilization, and early return of wrist function. Buttress plates reduce and stabilize vertical shear intra-articular fractures through an antiglide effect, whereas conventional and locking plates address comminution and/or preserve articular congruity/reduction. With conventional and locking plates, intraarticular fractures are directly reduced; with buttress plates, the plate itself helps reduce the intra-articular fracture. Complications associated with plating include tendon irritation or rupture and the need for plate removal. J Am Acad Orthop Surg 2005;13: Distal radius fractures constitute up to 15% of all extremity fractures. 1 Patients include both active elderly individuals and younger persons involved in high-energy trauma. Consequently, restoration of wrist function to close to preinjury levels is of concern to patients in both groups. Anatomic restoration of the distal radius and ulna is of major importance in achieving normal wrist function; open reduction has become increasingly useful in reaching this goal. The advantages of plating include accurate restoration of bony anatomy, stable internal fixation, a decreased period of immobilization, and early return of wrist function. Recent advances in plate design can help reduce or eliminate additional steps to augment stability, such as bone void filler, supplemental pins, and external fixation. A thorough understanding of plating alternatives is necessary to tailor treatment methods appropriately. Anatomy Distal Radius The distal radius consists of three independent articular surfaces the scaphoid facet, lunate facet, and sigmoid notch (Fig. 1). The scaphoid facet is part of the lateral distal radius, which includes the radial styloid. The medial aspect of the distal radius consists of the lunate facet and sigmoid notch. The sigmoid notch is nearly perpendicular to the lunate facet and articulates with the distal ulna to form the distal radioulnar joint (DRUJ). The close proximity of the sigmoid notch to the lunate facet implies that any injury to the medial aspect of the distal radius, whether intra-articular or extraarticular, involves the DRUJ. The lunate facet and its strong ligamentous attachments to the proximal carpal row and the ulnar styloid form the medial complex of the distal radius. The carpus is nearly always displaced with the volar and/or dorsal medial fragment of the distal radius because of the exceptionally strong ligaments of the medial complex. 2 Distal Ulna and Distal Radioulnar Joint The head of the ulna articulates with the sigmoid notch of the distal radius and abuts the triangular fibrocartilage complex (TFCC) and the ulnar carpus. Because the base of the ulna styloid (fovea) is the insertion point for much of the TFCC and important ulnocarpal ligaments, its integrity is critical to the stability of the DRUJ. 3 Dr. Nana is Staff Physician, Department of Orthopaedic Surgery, JPS Health Network, Fort Worth, TX. Dr. Joshi is Resident, Department of Orthopaedic Surgery, JPS Health Network. Dr. Lichtman is Chairman/Director, Department of Orthopaedic Surgery, JPS Health Network. None of the following authors or the departments with which they are affiliated has received anything of value from or owns stock in a commercial company or institution related directly or indirectly to the subject of this article: Dr. Nana, Dr. Joshi, and Dr. Lichtman. Reprint requests: Dr. Nana, JPS Health Network, 1500 South Main Street, Fort Worth, TX Copyright 2005 by the American Academy of Orthopaedic Surgeons. Vol 13, No 3, May/June

2 Plating of the Distal Radius Figure 1 Distal radius anatomy. The fracture line between the volar medial and dorsal medial columns extends into the sigmoid notch and thus must also be evaluated on postreduction radiographs. (Reproduced with permission from Trumble TE, Culp RW, Hanel DP, Geissler WB, Berger RA: Intra-articular fractures of the distal aspect of the radius. Instr Course Lect 1999;48: ) Inset, Columnar classification of distal radius and ulna. Columnar Classification of the Distal Radius and Ulna Conceptually, the distal radius and ulna may be divided into three columns based on the anatomy (Fig. 1, inset); this columnar classification then can be used to guide treatment plans. The distal radius is divided into the lateral and medial columns, which anatomically correlate with the scaphoid facet and lunate facet, respectively. The medial column of the distal radius is further subdivided into dorsal medial and volar medial columns. The lateral, dorsal medial, and volar medial columns correspond with Melone s 2 system for classifying intra-articular distal radius fractures. The ulnar column represents the ulnar styloid and the TFCC. Pathophysiology In most activities of daily living, the dorsum of the distal radius is subject to tensile forces, whereas the volar surface is subject to compression. This is reflected in the bony architecture of the distal radius, with its strong volar buttressing cortex and thinner cancellous dorsal surface. When the wrist is subjected to a nonphysiologic load, as in a dorsally directed compression force (eg, a fall on the outstretched hand), predictable fracture patterns result. Melone 2 aptly described the four major components of intra-articular distal radius fractures as radial styloid, dorsal medial, volar medial, and shaft (Fig. 1). The transverse coronal split between the dorsal and volar medial distal radius can be difficult to assess on plain radiographs. 4 In many ways, the combinations of displaced Melone components reflect variants of fracture types and classification described in the past. For example, isolated radial styloid displacement represents a chauffeur s fracture. Volar medial displacement describes Barton s fracture; displacement of the dorsal medial fragment represents the common reversed Barton s or dorsal compression fracture. Displacement of all articular as a unit is comparable to the classic extra-articular Colles fracture (dorsal) or to Smith s fracture (volar). Associated Injuries Associated injuries must be considered in any comprehensive treatment plan for patients with distal radius and ulna fractures. Up to 68% of distal radius fractures are associated with softtissue injuries, such as partial or complete tears of the TFCC, scapholunate ligament, and/or lunotriquetral ligament. 5,6 Fractures involving the lunate facet (the medial aspect of the distal radius) and fractures of the radial styloid cause the most intracarpal injuries because of the strong ligamentous interconnections between the distal radius and carpus. 5 Intracarpal ligament disruption does not have to be repaired unless gross instability is noted on postreduction radiographs (eg, scapholunate diastasis). The 4- to 6-week immobilization necessary for distal radius healing is usually sufficient for ligament healing in nondisplaced injuries. Radiographic and clinical examinations of the injured wrist after surgical reduction are helpful in evaluating the integrity of the DRUJ and TFCC, both components of the ulnar column. TFCC tears are also common, particularly when the medial column of the distal radius and/or the ulnar styloid is intact. A fracture of the ulnar styloid base and significant displacement (>2 mm) of an ulnar styloid fracture increase the risk of DRUJ instability. 7 Treatment of the ulnar column is focused on restoring DRUJ stability by closed, percutaneous, or open treatment of the ulnar styloid and the TFCC. Imaging Studies Posteroanterior (PA) and lateral radiographs are necessary for every patient with a distal radius injury. The lateral view of the wrist places the anterior surface of pisiform between the volar surface of the scaphoid (the scaphoid tuberosity) and the anterior surface of the capitate. 8 Treatment options for distal radius fractures are based on the initial injury as well as on radiographs made after closed reduction. If the initial injury position is within acceptable guidelines 9 (Table 1) for the patient s functional requirements, any loss of reduction is usually insignificant as 160 Journal of the American Academy of Orthopaedic Surgeons

3 Arvind D. Nana, MD, et al Table 1 Guidelines for Acceptable Reduction of Distal Radius Fractures* 1. Radial shortening <5 mm at the DRUJ compared with the contralateral side 2. Radial inclination on posteroanterior radiographs >15 3. Sagittal tilt on the lateral projection between 15 dorsal tilt and 20 volar tilt 4. Intra-articular step-off or gap <2 mm of the radiocarpal joint Articular incongruity <2 mm of the sigmoid notch of the distal radius *These guidelines must be individualized to accommodate each patient s functional activity levels and general medical status. Adapted with permission from Graham TJ: Surgical correction of malunited fractures of the distal radius. J Am Acad Orthop Surg 1997;5: appropriate radiographs of the uninjured contralateral wrist are recommended to evaluate the patient s normal anatomy and corresponding radiologic measurements. Plain radiographs may be insufficient to assess the extent of intraarticular and extra-articular fragmentation and injury to the DRUJ. Axial computed tomography (CT) scans with sagittal and coronal plane reconstructions can aid in visualizing diepunch fractures, volar rim fractures, and scaphoid facet fractures. Treatment of Distal Radius Fractures long as the fracture is adequately immobilized and protected. Conversely, unacceptable initial displacement often means that loss of reduction after nonsurgical treatment may require surgical intervention. The initial postinjury lateral view of the distal radius will demonstrate either the more common dorsal displacement or the less frequent volar displacement of the distal radius columns. The direction of initial displacement on the lateral radiograph generally correlates with the side of both greatest cortical comminution and required initial treatment. For example, if the lateral view shows dorsal displacement of the lunate facet, then the dorsal surface will have the greatest cortical fragmentation, and reduction will initially be focused dorsally. Postreduction or traction radiographs also are useful in assessing whether the distal radius fracture is intra-articular or extra-articular. The extent of cortical comminution is more easily visualized on postreduction radiographs than on initial postinjury radiographs. 11 All plain radiographs of distal radius fractures should include evaluation of radial inclination, radial length, ulnar variance, radial tilt, 9 articular step-off or gap, sigmoid notch step-off or gap, DRUJ subluxation/dislocation, and the presence and extent of displacement of ulnar styloid fractures (Fig. 2). Because of individual variability, All patients with distal radius fractures warrant a trial of closed reduction and plaster immobilization; ex- Figure 2 The various angles to assess in distal radius fractures. A, Radial inclination (RI; normal, 22 ). B, Radial length (RL; normal, 12 mm). C, Ulnar variance (UV; normal, 0 to 2 mm). D, Radial tilt (RT; normal, 11 volar). (Reproduced with permission from Graham TJ: Surgical correction of malunited fractures of the distal radius. J Am Acad Orthop Surg 1997; 5: ) Vol 13, No 3, May/June

4 Plating of the Distal Radius ceptions include those with open injuries, those who cannot tolerate immobilization, and those with volar or dorsal vertical shear fractures (Barton s fracture). Multiple trauma is also an indication for early surgical intervention. If the fracture can be reduced to within acceptable guidelines (Table 1) and maintained in satisfactory alignment by plaster sugar-tong splint immobilization, it is considered to be stable.an unstable fracture is characterized by inadequate reduction of a displaced fracture fragment or by the inability to maintain reduction after closed fracture manipulation. Depending on functional expectations, surgical treatment may be considered for unstable fractures involving the medial column of the distal radius (Fig. 3). Determining short-term stability after closed reduction is difficult and is based largely on personal experience in the treatment of distal radius fractures. If the surgeon thinks that a fracture is unstable and may present an unacceptable risk to the patient, then early open treatment with fixation should be considered. Successful closed treatment requires attention to detail by the physician as well as complete patient compliance with postreduction protocols. Normal wrist and forearm motion subjects the dorsal metaphysis of the distal radius to both tensile and compressive forces, but the volar surface transmits greater compressive forces. 8 Restoration of these biomechanical relationships is necessary to establish a stable reduction of the distal radius fracture. The first step toward a stable reduction is to create a stable volar buttress. In distal radius fractures with dorsal comminution, volar integrity is reestablished by accurate cortical apposition of the large volar. With comminuted volar or inherently unstable volar vertical shear fractures (volar Barton fractures), stable fracture reduction can be achieved by placement of a volar buttress plate. Once volar sta- bilityisrestored,thedorsalmetaphys- eal can be reduced against the stable volar buttress using external fixation, percutaneous pins, and/ or bone void filler (bone graft). 8 Autograft, allograft, or other bone graft substitutes may be used to fill the defect created after reduction of distal radius fractures. Comminuted are characterized by more compressed cancellous bone and a greater void after reduction. Conversely, large are associated with less compressed cancellous bone and thus a lower requirement for bone grafting. A bone void filler has several advantages, including mechanical support, 12 providing osteoconductive material for the bone defect, faster bone healing, and decreased incidence of loss of reduction Hydroxyapatite cement without additional fixation is inadequate for the treatment of distal radius fractures; 16 it should be combined with external fixation to supplement any bone void filler. Medial column fracture of the distal radius Unstable volar after closed reduction Stable volar after closed reduction* or no volar fracture Unstable dorsal Stable dorsal or no dorsal fracture Unstable dorsal Stable dorsal Splint immobilization Large dorsal Small dorsal Volar buttress plate Large dorsal Small dorsal Dorsal bone void filler and neutralization external fixation Conventional volar plate with dorsal percutaneous pins Volar plate with distal locking screws/pegs Conventional volar plate with bone void filler and external fixation Percutaneous pins and splint immobilization Dorsal buttress plate Dorsal plate with distal locking screws/pegs Volar plate with distal locking screws/pegs Figure 3 Plating recommendations for fractures of the medial column of the distal radius. Treatment choice depends on surgeon preference and experience. * = accurate cortical apposition of the volar. 162 Journal of the American Academy of Orthopaedic Surgeons

5 Arvind D. Nana, MD, et al Restoration of volar stability has important radiocarpal implications because the stronger and more important radiocarpal ligaments are attached to the volar surface. Volar integrity therefore is critical because it facilitates adequate reduction of dorsal against a stable volar buttress and because it prevents possible volar radiocarpal instability. 8 Plate Fixation Plate fixation is primarily indicated for unstable fractures of the volar medial column of the distal radius; it is also helpful for combined volar and dorsal medial column injuries. Although some authors recommend dorsal plates for isolated dorsal medial column injuries of the distal radius, other methods of treatment are available for these injuries. Volar plates with locking screws or pegs may be effective for extensive dorsal comminution. Distal radius plates are categorized by location of use and type of plate. Plates categorized by location may be used on the dorsal medial, volar medial, and radial styloid aspects of the distal radius. Certain plate designs address two areas simultaneously (ie, dorsal medial distal radius and radial styloid, or volar medial distal radius and radial styloid). Smaller implants are also available to stabilize each area separately. The two principal types of distal radius plates are buttress plates and plates that can span comminution and/or maintain articular congruity and reduction. Only the buttress plate, with its antiglide effect, reduces intra-articular fractures (eg, volar Smith or Barton fractures [Fig. 4] or dorsal Barton fracture). All other distal radius plates require direct reduction of intra-articular fractures; the plating serves to maintain the alignment. Plates that maintain alignment can be further subdivided into two types: conventional and locking. In conventional plate design, stability of the construct is ultimately achieved through apposition of the bone and plate by screw purchase in the bone. Conventional plates can be used dorsally or volarly. The use of dual small conventional plates on the dorsal distal radius also has been described. 17 When cortical or cancellous screws are used in the distal holes of the buttress plate, they are most effective if the opposite cortex is not comminuted. If the opposite cortex is comminuted, the surface could collapse because of both axial forces across the wrist joint and toggle of the screws in the plate, which may result in loosening of the distal screws. 18 Plates with locking distal screws or pegs support the subchondral bone and resist forces across the articulation that may displace the articular (Figs. 5, 6, and 7). Locking screws or pegs offer numerous advantages over regular screws because their stability is achieved through plate design. The screws or pegs become fixedangle devices via threaded heads that engage the threaded distal screw holes of the plate for stability. New plate designs allow locking screw insertion in the most distal screw holes as well as in the proximal screw holes. Of historical note, the dorsal plate used by Gesensway et al 19 employed a blade plate construct with multiple tines to achieve fixed-angle fixation. Locking screws or pegs support the subchondral bone without relying on the purchase of the screws or pegs in bone, and they are independent of opposite cortex comminution. Accordingly, no bone void filler is required to prevent collapse at the site of comminution. The distal screws or pegs whether cortical, cancellous, or fixed-angle serve to maintain reduction of articular, but they do not directly reduce the articular fracture. Figure 4 The antiglide effect of a buttress plate helps reduce a volar vertical shear fracture (volar Barton fracture) of the distal radius. The most proximal screw is placed first; the penultimate distal screw (A) reduces the fracture (arrows) (B) before placement of the final distal screw (C). (Reproduced with permission from Jupiter JB: Complex articular fractures of the distal radius: Classification and management. J Am Acad Orthop Surg 1997; 5: ) Distal Radius Plating Plating offers direct restoration of the distal radius through stable fixation. The stability of the construct ensures more predictable healing of the fracture and thus shortens the period of immobilization of the wrist. The principal advantage of distal radius plating is the early return of wrist function, an important criterion for patients who expect wrist function after injury to return to preinjury levels. Conventional plates can be used for buttress and/or neutralization support of a distal radius fracture. Plates with locking screws or pegs do not rely on anatomic contour of the plate to obtain stability. Stabilization of the opposite cortex through locking screws or pegs significantly decreases or eliminates the need for further stabilization of the opposite cortex fragmentation. Vol 13, No 3, May/June

6 Plating of the Distal Radius lization. For an unstable distal shaft fracture with minimal or no comminution that is either dorsally or volarly displaced, a volar plate is sufficient to achieve stable fixation. A locking volar plate does not offer any specific advantage over conventional volar plating systems for this type of fracture. However, for an extraarticular fracture with dorsal or volar comminution, a locking volar plate may offer stability; it also restores length without the mobilization of extensor tendons that is required for dorsal plating. A dorsal plate for an extra-articular fracture with dorsal comminution is considered excessive treatment without sufficient benefit because these fractures can be routinely pinned and stabilized in a closed fashion. Bone void filler and external fixation may be used for severely comminuted extra-articular fractures. Figure 5 A, With conventional screws, stability is achieved through friction between the plate undersurface and the underlying bone (arrows) resulting from screw compression at the interface. This stability is augmented by bicortical screw purchase, which also decreases toggle between the screw and plate hole (represented by the rectangles). Friction at the interface must be higher than the axial forces to ensure absolute stability. Thus, anatomic contouring of the conventional screw/plate system is needed to obtain a stable construct. B, In a locking screw system, the threaded screw head locks in the threaded screw hole of the plate to attain stability. Consequently, axial forces in the bone are transmitted to the plate rather than the screw, and no screw toggle can occur (arrows). Because stability with a locking screw does not require compression between the bone and the plate (rectangles), the periosteal blood supply under the plate is preserved. (Adapted with permission from Appenzeller A, Christensen R, Frenk A, Gilbert S, Schavan R: The development of the distal femur LISS. Injury 2001;32[suppl 3]:5-25.) Surgical Treatment Extra-articular Distal Radius Fractures These injuries are transverse or short oblique fractures proximal to the DRUJ and are usually amenable to closed treatment methods with supplementary percutaneous pin stabi- Figure 6 In the distal radius, the principal advantage of a plate with locking screws is stability of the construct, even in the presence of segmental bone defect or comminution of cortex opposite the plate. Because the screws lock into the plate, the axial forces are transmitted to the plate. This diagram shows locking screws along the entire plate. F = axial force in the direction of the arrow. (Adapted courtesy of Synthes [USA], Paoli, PA.) Intra-articular Distal Radius Fractures The concept of four-part displacement is useful in conceptualizing a treatment algorithm, especially with regard to the indications for distal radius plating. When evaluating a patient with a distal radius fracture, three distinct areas (columns) are assessed (Fig. 1, inset). The medial column of the distal radius represents Melone s dorsal and volar die-punch radius ; plates and/or bone void filler are particularly applicable for restoration of this column. The radial styloid component the lateral distal radius column is then reviewed to determine whether localized treatment is sufficient (eg, percutaneous pins or screws for the displaced radial styloid) or whether treatment should be combined with fixation of the medial column of the distal radius (eg, a volar or dorsal plate that also fixes the styloid). Finally, the ulnar column, representing the TFCC and the ulnar styloid components, is addressed. Intra-articular Fractures of the Lateral Column The radial styloid fracture and its corresponding scaphoid facet are usually displaced proximally by axial compression forces. Often the fragment is rotated in pronation, but this is not easily appreciated on routine radiographs. CT scan and dynamic fluoroscopy can help delineate this 164 Journal of the American Academy of Orthopaedic Surgeons

7 Arvind D. Nana, MD, et al Figure 7 Anteroposterior (A) and lateral (B) radiographs of a distal radius injury. The fracture, which demonstrates volar and dorsal instability, is fixed with a volar locking plate (C and D). The dorsal instability is best seen in the postoperative lateral view (D), which shows a dorsal gap just proximal to the locking pegs. The locking pegs stabilize both the dorsal and volar articular. In this patient, bone void filler was not used in the dorsal gap, and the distal ulna was not surgically stabilized. (Courtesy of Arvind D. Nana, MD, Fort Worth, TX.) rotational deformity. Isolated radial styloid fractures should raise concerns about concomitant intracarpal injury. A displaced radial styloid usually can be reduced by closed means (ligamentotaxis by wrist flexion and ulnar deviation) and stabilized with two percutaneous pins. Reduction and pin placement are assessed intraoperatively with fluoroscopy or, if open reduction is used, under direct visualization (Figs. 8 and 9). Occa- sionally the radial styloid fragment must be manipulated into position, using the pins as joysticks, before securing the position by advancing the pins into the opposite cortex. The direction of the styloid pins is from ra- Figure 8 Anteroposterior (A) and lateral (B) radiographs of a wrist at initial presentation. Anteroposterior (C) and lateral (D) radiographs of the wrist in longitudinal traction. The patient is immobilized in a plaster sugar-tong splint. (Courtesy of David M. Lichtman, MD, Fort Worth, TX.) Vol 13, No 3, May/June

8 Plating of the Distal Radius Figure 9 Same patient as in Figure 8. Anteroposterior (A) and lateral (B) radiographs made 1 week after injury. The laterally displaced radial styloid fragment and volarly displaced volar medial fragment (arrows) are evident. Instability of these is easily demonstrated by their inability to maintain initial closed reduction. Anteroposterior (C) and lateral (D) postoperative radiographs show that the volar medial fragment is stabilized with a volar plate. The radial styloid is fixed with two percutaneous pins; the dorsal cortex with its large dorsal is stabilized with a dorsal percutaneous pin. The ulnar styloid also was stabilized because of the fracture through its base, marked displacement (>2 mm), and clinical instability of the DRUJ after stabilization of the distal radius. (Courtesy of David M. Lichtman, MD, Fort Worth, TX.) dial volar to ulnar dorsal. Other options for styloid fixation include percutaneous lag screw fixation or a small buttress plate and pins.20 Plate fixation of the radial styloid is usually done in combination with stabilization of medial column injuries of the distal radius. Volar or dorsal distal radius plates include radial styloid stabilization in their construct and therefore do not need separate radial styloid plating or pinning. Certain smaller implant designs are available for separate plating of radial styloid fractures, but this is almost always in combination with medial column stabilization (whether dorsal or volar). Separate lateral and medial column plating of the distal radius is most mechanically stable when the plates are angled 50 to 90 to each other.11,17,20,21 Separate radial styloid plates are placed on the dorsal radial or most radial aspect of the distal radius; this placement requires a lowprofile design to avoid irritation of the brachioradialis tendon or dorsal extensor tendons. 166 Intra-articular Fractures of the Medial Column Unstable volar fractures are amenable to volar plate stabilization. If the fracture is isolated (ie, there is no dorsal fragment instability), then a simple buttress plate may be used to reconstitute the volar cortex. If the volar metaphysis is comminuted, bone void filler may be used to fill in the gap and also to support the distal articular surface. The integrity of the joint should not be violated by dissecting the volar radiocarpal ligaments. When necessary, the volar cortex can be hinged open like a book to inspect and realign volar intraarticular injuries. When dorsal fragment instability also is present, several options are available. If a volar buttress plate has been applied, then the dorsal fragment must be stabilized from a dorsal approach. If the dorsal fragment is large, it can be fixed by one or (preferably) two percutaneous cross pins entering the dorsal medial fragment distally and aimed proximally and ra- dially (Figs. 8 and 9). As with the radial styloid fragment, percutaneous pins can be used as joysticks to manipulate the dorsal fragment into position. The pins also may be placed into the fracture line (intrafocal Kapandji pinning [Fig. 10]), starting more perpendicular to the dorsal cortex, and then used to reduce the dorsal fragment by moving the pins more nearly parallel to the dorsal cortex, with subsequent fixation into the volar cortex. If the dorsal medial fragment is comminuted, reducing and holding the area with pin fixation may be difficult. The fracture can be opened dorsally, usually through a longitudinal approach between the third and fourth dorsal extensor compartments. An approach ulnar to the fourth compartment also may be used if the comminution is limited to the dorsal ulnar corner and semilunar notch. The floor of the third extensor compartment is incised longitudinally; then the fourth extensor compartment (sheath and tendons) is sharply ele- Journal of the American Academy of Orthopaedic Surgeons

9 Arvind D. Nana, MD, et al Disadvantages of dorsal plates include the need for mobilization of extensor tendons to achieve proper plate placement, possible tendon irritation or rupture because of a prominent plate or screws, and the possibility of additional surgery to remove the symptomatic dorsal plate. In isolated unstable fractures of the dorsal medial column, the decision to treat with pin fixation or with open bone grafting plus neutralization external fixation depends on the size of the. Treatment is the same as when combined with volar instability: percutaneous pins for large or open reduction, bone void filler, and external fixation for comminuted fractures (small ). Once again, low-profile dorsal plates can be applied instead of an external fixator, but locking screws or pegs are not necessary in this instance. A lateral column injury of the distal radius is usually treated concomitantly or after stabilization of the medial column. As noted, if the fracture pattern permits, the styloid can be fixed with either a volar or dorsal plate. In most instances, the radial styloid can be fixed separately using two percutaneous pins, as described for isolated radial styloid fractures. Apercutaneous lag screw or a small dorsal radial buttress plate are also options. Surgical Approach Figure 10 With intrafocal Kapandji pinning, the pin is placed through the fracture site and maneuvered to elevate the fragment. Once adequate reduction is achieved, the pin is then driven through the opposite cortex to achieve stability. This technique can be used to restore radial inclination (A) or volar tilt (B). (Adapted with permission from Palmer AK: Fractures of the distal radius, in Green DP [ed]: Operative Hand Surgery. New York, NY: Churchill Livingstone, 1993, pp ) vated off the dorsal distal radius. Bone grafting of the dorsal metaphysis is now possible. If the joint needs to be viewed, the dorsal capsule can be incised transversely. Reduction under direct visualization usually can be done, and bone void filler is often used to stabilize and buttress the dorsal cortex. If necessary, a transverse capsular incision may be used to explore the radiocarpal joint and reduce intra-articular or intracarpal injuries. Some surgeons use low-profile dorsal plates at this point to maintain articular reduction and stability; others apply an external fixator for 3 to 4 weeks to avoid use of a dorsal plate. An alternative for treating both dorsal and volar instability is to use a plate with locking screws or pegs to transfix both volar and dorsal cortices of the medial column of the distal radius (Fig. 7). Satisfactory results have also been achieved using locking screw plate combinations from the dorsal side Although dorsal plates do permit adequate healing of the fracture, their secondary effects particularly on surrounding soft-tissue structures render them a less appealing option. Volar Radial Approach The volar radial (Henry) approach is utilitarian; it can expose the entire volar radial surface up to the DRUJ (Fig. 11, A). This exposure uses the interval between the flexor carpi radialis (FCR) and the radial artery or goes through the floor of the FCR tendon sheath. The pronator quadratus muscle is elevated in a subperiosteal fashion to visualize the volar distal radius. 25 Orbay 26 and Orbay and Fernandez 27 also describe the release of the first extensor compartment and the insertion of the brachioradialis off the lateral distal radius to permit access to the dorsal surface and to facilitate the reduction of the lateral column of the distal radius (radial styloid). Release of the volar capsule or the ligamentous attachments on the volar rim may lead to volar radiocarpal instability and should be avoided. Carpal tunnel release through the distal extension of this approach is not recommended because of potential injury to the volar cutaneous branch of the median nerve. If carpal tunnel release is indicated, a separate standard or a mini carpal tunnel incision is recommended. Prophylactic carpal tunnel release is not routinely performed 21,28,29 unless acute carpal tunnel symptoms are present or unless the distal fragment is significantly dorsally displaced for a prolonged period of time. Volar Ulnar Approach The volar ulnar approach offers limited exposure to the radial column and is indicated for injuries to the volar aspect of the medial column and the DRUJ (Fig. 11, B). The interval between the flexor carpi ulnaris and the Vol 13, No 3, May/June

10 Plating of the Distal Radius Figure 11 A, The volar radial approach uses the interval between the flexor carpi radialis tendon and the radial artery. The pronator quadratus is elevated sharply, starting at its insertion on the distal radius. B, Top detail, the volar ulnar approach can be extended distally to release the median nerve from the carpal tunnel. Bottom detail, at the level of the distal radius, the flexor tendons and the median nerve are retracted radially to expose the volar medial distal radius. (Adapted with permission from Fernandez DL, Jupiter JB: Fractures of the Distal Radius. New York, NY: Springer, 1996, pp ) finger flexor tendons is used for this approach. While retracting the flexor tendons radially and protecting the ulnar nerve and artery, the pronator quadratus muscle is mobilized off the distal ulna. This exposure has the advantage of permitting distal extension to complete a carpal tunnel release. Postoperative Management After surgery, immobilization is desirable to facilitate soft-tissue healing and resolution of swelling. Plaster splinting is preferable to the use of circumferential or bivalved casts because use of casts may lead to potential complications such as finger edema and compartment syndrome. Postsurgical follow-up includes suture removal at 10 to 14 days and serial radiographs for the first 2 weeks if deemed necessary. Arm elevation and finger range of motion are important components of early rehabilitation. Conversion to a circumferential cast may be considered at 2 weeks; however, complete wrist immobilization beyond the fourth postoperative week usually is not desirable because it negates the advantage of early restoration of wrist stability with plating. During the period of immobilization, therapy is focused on finger motion; once immobilization is discontinued, therapy expands to include wrist motion (flexion, extension, ulnar deviation, and radial deviation) and forearm rotation (pronation, supination). A removable Velcro wrist splint then can be provided for support and comfort while the patient engages in gentle activities of daily living and active range-of-motion exercises. With plating of extra-articular fractures, or for fractures with well-fixed intra-articular, immobilization can be discontinued as early as 2 weeks after surgery as long as the incision is sufficiently healed and edema has decreased to allow wrist motion. For more complex intra-articular fractures treated with plating, immobilization for at least 4 weeks is necessary to permit healing of the intraarticular and to allow wrist motion without risk of displacement of the intra-articular. For 6 to 8 weeks, splints can be worn at night, and only light physical therapy is recommended. Strenuous pushing, pulling, twisting, or lifting should be avoided for the first 3 months to facilitate optimal bone healing. 168 Journal of the American Academy of Orthopaedic Surgeons

11 Arvind D. Nana, MD, et al Complications The most common complication of plate fixation in the distal radius is tendon injury; 25% of patients evaluated reported everything from tendon irritation to frank rupture. 17,24,30 With the volar plate, tendon injuries have included rupture of the flexor pollicis longus, 22,31,32 FCR tenosynovitis, 28 and dorsal extensor tendon involvement as a result of protruding screws. 28,33 Dao et al 34 reported radial artery pseudoaneurysm secondary to volar distal radius plate design. Median nerve dysfunction (ie, paresthesia, carpal tunnel syndrome, or reflex sympathetic dystrophy) is associated with volar plating, but routine prophylactic carpal tunnel release in this scenario is not considered standard treatment. 21,28,29 Adverse effects are more common with dorsal plating than with volar plating. As with dorsal plates, tendonrelated complications requiring plate removal also occur after volar plating; in one study, 13 of 73 patients (18%) required plate removal after volar plating. 32 Tendon irritation is thought to be caused by prominent or sharp plate edges, 17,23,30 prominent or loose screws, 35 and cellular reaction to the titanium metal of the plates. 34,36 Extensor tendon rupture can be caused by screws that are loose or backing out, 30,33,37 by sharp edges created by cutting of the plate, 17 and by prominent design of the distal aspect of the dorsal plate. 36,38,39 Many authors have reported a high incidence (up to 30%) of dorsal plate removal secondary to tendon inflammation or rupture. 17,23,30,34-36 To prevent tendon injury, some recommend that a portion of the extensor retinaculum be interposed between the plate and the tendon or tendon sheath, 21,30,40 or that the dorsal plates be routinely removed. 23,37,40 Tendon rupture has been reported as early as 8 weeks and as late as 7 months after surgery. 30,38 Plate breakage is another reason for plate removal. 37 Loss of reduction also can be a problem and is seen more frequently with the use of conventional plates when the opposite cortex is not further augmented with pins, bone void filler, or external fixation. 24,34,41,42 Outcomes Functional outcomes of distal radius fractures depend on multiple factors, including radial shortening, radial inclination, sagittal tilt, intra-articular step-off or gap, and articular congruity of the sigmoid notch (Table 1). Although intra-articular step-off >2 mm has been shown to lead to radiographic osteoarthritis, this does not necessarily correlate with poor functional outcome. 10 Radial shortening >5 mm, however, may have a marked impact on outcome because it can affect both the DRUJ and the radiocarpal joint. 9,10,43 Outcome studies for each type of dorsal plate design (conventional, dual, and locking) have been performed, but the average follow-up is only 12 to 19 months for population groups ranging from 21 to 73 patients. Two studies of conventional plate design demonstrated 72% to 95% goodto-excellent functional results, with a reported complication rate of 20% to 23%. The largest study evaluated dual dorsal plating in the treatment of distal radius fractures; however, even with 97% good-to-excellent results, the incidence of complications was 21%. 17,24,30 Of the dorsal plates with locking screws or pegs, the Synthes pi plate (Paoli, PA) demonstrated a 57% goodto-excellent outcome and a 23% complication rate. 39 Subsequent reports on the pi plate show good-toexcellent functional results of 56% to 68%. 21,44 All of the studies on dorsal plating, regardless of design, include the complication of plate removal as a secondary procedure. 21,39,44 The reason for plate removal is usually extensor tenosynovitis or rupture. Keating et al 42 examined the results of the volar buttress plate in 79 patients and found that functional recovery associated with malunion was significantly less than in those with good anatomic restoration. Malunion was the most frequent complication (28%) of all complications reported (40.5%). 42 Orbay 26 and Orbay and Fernandez 27 examined the use of the volar plate with locking pegs for the treatment of dorsally displaced fractures of the distal radius; they reported 100% good-to-excellent results. The authors attributed the success of the treatment plan to stable internal fixation and preservation of dorsal soft tissues, which facilitate early fracture healing; decreased need for bone grafting; and low incidence of tendon injury. In their study, 9 of 29 patients (31%) had preoperative median nerve symptoms and also underwent carpal tunnel release. One patient had extensor tendon irritation secondary to a long peg that necessitated hardware removal, but all other plates were left in place. 26,27 No study has a follow-up >19 months; thus, conclusive long-term recommendations for distal radius plating cannot be made based on these reports. Summary Improved restoration of the anatomic relationship in unstable distal radius fractures can lead to improved, early functional outcome; the trend is to achieve this goal through open reduction and internal fixation. Benefits of plate fixation include direct visualization of the fracture, stable internal fixation, a shortened period of immobilization, and early return of extremity function. Recent plate designs include locking screws or pegs that maintain articular reduction as well as span and stabilize the comminution of the opposite cortex. The outcome of plating distal radius fractures cannot be compared to Vol 13, No 3, May/June

12 Plating of the Distal Radius other surgical options because of a lack of long-term follow-up and the wide variation of indications for plating in published studies. The threecolumn system for distal radius and ulna fractures is a simple and practical approach to understanding and treating these common, yet sometimes complex, injuries. The risks and benefits of plating must be balanced for each patient and weighed with complete understanding of the pathologic anatomy and physiology of each specific fracture pattern. The OKO video Intraarticular Distal Radius Fractures, by Christopher H. Allan, MD, is available at jaaos/main.cfm. References 1. Sanders WE: Distal radius fractures, in Manske PR (ed): Hand Surgery Update. Rosemont, IL: American Academy of Orthopaedic Surgeons, 1996, pp Melone CP Jr: Articular fractures of the distal radius. Orthop Clin North Am 1984;15: Palmer AK: The distal radioulnar joint. Orthop Clin North Am 1984;15: Andersen DJ, Blair WF, Steyers CM, Adams BD, El-Khouri GY, Brandser EA: Classification of distal radius fractures: An analysis of interobserver reliability and intraobserver reproducibility. J Hand Surg [Am] 1996;21: Geissler WB, Freeland AE, Savoie FH, McIntyre LW, Whipple TL: Intracarpal soft-tissue lesions associated with an intra-articular fracture of the distal end of the radius. J Bone Joint Surg Am 1996; 78: Richards RS, Bennett JD, Roth JH, Milne K Jr: Arthroscopic diagnosis of intra-articular soft tissue injuries associated with distal radius fractures. J Hand Surg [Am] 1997;22: May NM, Lawton JN, Blazar PE: Ulnar styloid fractures associated with distal radius fractures: Incidence and implications for distal radioulnar joint instability. J Hand Surg [Am] 2002;27: Nana AD, Lichtman DM: Distal-third forearm fractures. Available at htm. Accessed April 27, Graham TJ: Surgical correction of malunited fractures of the distal radius. J Am Acad Orthop Surg 1997;5: Knirk JL, Jupiter JB: Intra-articular fractures of the distal end of the radius in young adults. J Bone Joint Surg Am 1986; 68: Rikli DA, Regazzoni P: Fractures of the distal end of the radius treated by internal fixation and early function. J Bone Joint Surg Br 1996;78: Fernandez DL, Geissler WB: Treatment of displaced articular fractures of the radius. J Hand Surg [Am] 1999;24: Leung KS, Shen WY, Leung PC, Kinninmonth AWG, Chang JCW, Chan GPY: Ligamentotaxis and bone grafting for comminuted fractures of the distal radius. J Bone Joint Surg Br 1989;71: Putnam MD, Fischer MD: Treatment of unstable distal radius fractures: Methods and comparison of external distraction and ORIF versus external distraction-orif neutralization. J Hand Surg [Am] 1997;22: Trumble TE, Schmitt SR, Vedder NB: Factors affecting functional outcome of displaced intra-articular distal radius fractures. J Hand Surg [Am] 1994;19: Jeyam M, Andrew JG, Muir LT, McGovern A: Controlled trial of distal radial fractures treated with a resorbable bone mineral substitute. J Hand Surg [Br] 2002;27: Jakob M, Rikli DA, Regazzoni P: Fractures of the distal radius treated by internal fixation and early function. J Bone Joint Surg Br 2000;82: Small Fragment Locking Compression Plate (LCP): Technique Guide. Paoli, PA: Synthes (USA), 2002, pp Gesensway D, Putnam MD, Mente PL, Lewis JL: Design and biomechanics of a plate for the distal radius. J Hand Surg [Am] 1995;20: Swigart CR, Wolfe SW: Limited incision open techniques for distal radius fracture management. Orthop Clin North Am 2001;32: Hahnloser D, Platz A, Amgwerd M, Trentz O: Internal fixation of distal radius fractures with dorsal dislocation: π-plate or two ¼ tube plates? A prospective randomized study. J Trauma 1999; 47: Fuller DJ: The Ellis plate operation for Smith s fracture. J Bone Joint Surg Br 1973;55: Fitoussi F, Ip WY, Chow SP: Treatment of displaced intra-articular fractures of the distal end of the radius with plates. J Bone Joint Surg Am 1997;79: Finsen V, Aasheim T: Initial experience with the Forte plate for dorsally displaced distal radius fractures. Injury 2000;31: Trumble TE, Culp RW, Hanel DP, Geissler WB, Berger RA: Intra-articular fractures of the distal aspect of the radius. Instr Course Lect 1999;48: Orbay JL: The treatment of unstable distal radius fractures with volar fixation. Hand Surg 2000;5: Orbay JL, Fernandez DL: Volar fixation for dorsally displaced fractures of the distal radius: A preliminary report. J Hand Surg [Am] 2002;27: Jupiter JB, Fernandez DL, Toh C-L, Fellman T, Ring D: Operative treatment of volar intra-articular fractures of the distal end of the radius. J Bone Joint Surg Am 1996;78: Schneeberger AG, Ip WY, Poon TL, Chow SP: Open reduction and plate fixation of displaced AO type C3 fractures of the distal radius: Restoration of articular congruity in eighteen cases. J Orthop Trauma 2001;15: Carter PR, Frederick HA, Laseter GF: Open reduction and internal fixation of unstable distal radius fractures with a low-profile plate: Amulticenter study of 73 fractures. J Hand Surg [Am] 1998;23: Bell JSP, Wollstein R, Citron ND: Rupture of flexor pollicis longus tendon. J Bone Joint Surg Br 1998;80: Nunley JA, Rowan PR: Delayed rupture of the flexor pollicis longus tendon after inappropriate placement of the π plate on the volar surface of the distal radius. J Hand Surg [Am] 1999;24: Wong-Chung J, Quinlan W: Rupture of extensor pollicis longus following fixation of a distal radius fracture. Injury 1989;20: Dao KD, Venn-Watson E, Shin AY: Radial artery pseudoaneurysm complication from use of AO/ASIF volar distal radius plate: A case report. J Hand Surg [Am] 2001;26: Schnur DP, Chang B: Extensor tendon rupture after internal fixation of a distal radius fracture using a dorsally placed AO/ASIF titanium Pi plate. Ann Plast Surg 2000;44: Lowry KJ, Gainor BJ, Hoskins JS: Extensor tendon rupture secondary to the AO/ASIF titanium distal radius plate 170 Journal of the American Academy of Orthopaedic Surgeons