Fragment-Specific Fixation of Distal Radius Fractures

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CHAPTER 12 Fragment-Specific Fixation of Distal Radius Fractures

Leon S. Benson, MD, Robert J. Medoff, MD

Of the various types of distal radius fractures, those with intra-articular extension have the most to gain from operative intervention. Many of these fractures are inherently unstable and not amenable to conservative methods of reduction and cast immobilization. Treatment that fails to correct residual incongruity of the joint and leaves a significant step-off or gap in the articular surface can result in chronic osteoarthritis and pain.¹^–⁴ Furthermore, unreduced fragments that alter the geometry and normal kinematics of the radiocarpal or distal radioulnar joint can cause painful movement, restricted motion, and joint instability. Ideally, treatment should be directed at stable restoration of normal anatomy of the articular surface.

Although intra-articular fractures of the distal radius do not occur as a single, homogeneous pattern, the majority of these injuries contain a subset of five basic fracture elements: the radial column, ulnar corner, dorsal wall, volar rim, and free intra-articular fragments (Fig. 12-1). Occasionally, these fracture elements themselves may have further comminution. In addition to these cortical elements, these fractures may have other associated pathological processes, such as compressive damage to the metaphyseal bone, fractures of the distal ulna, and soft tissue injuries of the triangular fibrocartilaginous complex (TFCC), distal radioulnar joint (DRUJ), and radioulnar syndesmosis. In more complex fracture patterns, appropriate treatment of distal radius fractures often must be customized to the specific components and mechanism of the particular injury. Although recently there has been a rise in the popularity of fixed-angle volar plates for the treatment of distal radius fractures, this method of treatment can be inadequate for fractures with small distal fragments or injuries with complex, multiarticular patterns.⁵ Treatment starts with careful analysis of the injury and initial postreduction radiographs.⁶ When needed, computed tomography (CT) can supplement standard radiographs to help with the interpretation of the fracture pattern. These topics have been covered in previous chapters.

FIGURE 12-1 Fragment-specific classification. Articular fractures of the distal radius tend to propagate along recurrent pathways, resulting in generation of five basic fracture components: the radial column, ulnar corner, dorsal wall, free intra-articular, and volar rim. In addition to these distal radius fracture elements, impaction of the metaphyseal bone, DRUJ and distal ulna injuries, and intracarpal pathologic processes may affect the natural history of a particular fracture pattern.

Fragment-specific fixation is a treatment approach in which each independent major fracture fragment is stabilized with an implant specifically designed for that particular fracture element (Fig. 12-2).⁷^–¹⁰ One objective of fragment-specific fixation is to restore a stable, anatomical joint surface by direct and independent fixation of each major fracture fragment. As a general rule, fragment-specific fixation is a load-sharing construct in which each fracture element is pieced back together into a unified composite structure. Fragment-specific implants are intentionally designed to be extremely low profile and conform to the local surface topography at the site of application, avoiding the need for bulky plates that can irritate tendons or large distal screw holes that can cause further comminution of small distal fragments. Another goal of treatment is to achieve enough stability to allow motion immediately after surgery.

FIGURE 12-2 Fragment-specific implants. A, Radial pin plate for radial column fixation. B, Volar buttress pin for volar rim fixation. C, Ulnar pin plate for ulnar corner fixation. D, Small fragment clamp for dorsal wall fixation. E, Dorsal buttress pin for dorsal wall and free intra-articular fragment fixation. F, Small fragment clamp/buttress pin for combined dorsal wall and free intra-articular fragment fixation.

In some ways, fragment-specific fixation has certain similarities to simple, multiple Kirschner wires (K-wires). In each technique, individual fragments are reduced and secured to the proximal shaft. In each technique, a goal of treatment is to restore normal anatomy to the articular surface. Furthermore, each technique avoids extensive dissection and wide osseous exposure of the distal surface and eliminates fixation that depends on thread purchase in small distal fragments. Fragment-specific fixation, however, has some significant differences to fixation with multiple K-wires because it achieves a stable, load-sharing construct of the fracture components, allowing immediate motion without a cast postoperatively. In addition, fragment-specific fixation avoids potential problems of pin tract irritation and pin site infection, as well as the need to perform a second procedure to remove K-wires.

Fragment-Specific Implants

The radial border of the distal radius is often involved as a major component of distal radius fractures. In most cases this area breaks as the radial column, a single piece of bone that includes the scaphoid facet, the radial styloid, and the osseous pillar that extends proximally to the distal attachment of the brachioradialis tendon. The radial column is typically a large fragment that includes the orthogonal surfaces of the dorsal, radial, and volar cortices and is often a significant fracture element. Although trans-styloid pinning of the radial column is a simple technique, it usually results in rather tenuous fixation because stability is dependent on the stiffness of the K-wire as well as the purchase by the tip of the wire in the far cortex of the proximal fragment. Bending or small amounts of angulation of the K-wire at the site of purchase in the far cortex can result in significant shortening and displacement of the radial column fragment.

The radial pin plate is a fragment-specific implant designed specifically for stable fixation of the radial column fragment. Mechanically, this implant acts as an outrigger to add a second point of constraint to the pin at its entry site on the surface of the unstable radial column fragment. As a result, proximal drift of the K-wire is prevented because pin failure from bending or angulation at the site of purchase in the far cortex is eliminated. The radial pin plate creates a rigid pin construct that triangulates fixation to both near and far cortices of the proximal fragment. Because this maintains the length of the radial column, the carpus is held out to length, preventing collapse of the proximal carpal row into remaining unstable fragments within the lunate facet.

Although the primary function of the radial pin plate is to provide rigid fixation of the radial column, the radial pin plate has a secondary role that can also help with stabilization of many articular fractures. Although the plate is thin, because it is applied along the plane of the radial border, it is extremely stiff in resisting bending moments caused by flexion and extension movements of the wrist. Moreover, the radial pin plate is slightly overcontoured to the curve of the radial border and flattens like a leaf spring against the bone as it is secured to the proximal fragment. This causes the plate to push the distal fragment toward the ulna, locking intra-articular fragments in place and improving DRUJ stability by seating the ulnar head within the sigmoid notch of the radius. Because this property of the radial pin plate is quite effective in securing intra-articular fragments in whatever position they happen to be, it is generally a good idea to ensure that articular fragments are first fully reduced before securing the radial pin plate to the proximal fragment.

Although radial shear fractures are relatively uncommon, it should be noted that these injuries do not generate a typical radial column fragment. In this fracture pattern, the carpus translates radially, causing a failure in shear across the tip of the radial styloid. Radial shear fractures have a characteristic radiographic image that shows a small triangular fragment that involves only the tip of the styloid; unlike the true radial column fracture, the fracture line does not extend proximally into dorsal, radial, and volar cortical surfaces. These injuries are associated with significant shear damage to the articular surface and often have free chondral fragments present in the joint as well as ligamentous tears within the carpus. In addition, injury to the TFCC and/or ulnar styloid is often observed with this pattern of injury. Although a radial pin plate can effectively stabilize radial shear fractures, in healthy bone satisfactory fixation can often be simply achieved with one or two screws.

The ulnar pin plate is a fragment-specific implant that is designed for dorsal fixation of the ulnar corner fragment. This fragment includes the dorsal portion of the sigmoid notch and is typically the result of axial impaction of the lunate against the dorsal surface of the lunate facet. The ulnar corner fragment displaces proximally and dorsally and can cause problems with DRUJ function. Although sometimes this fragment can be quite small, the fracture line nearly always extends to the radial side of the dorsal insertion of the DRUJ capsule. The ulnar pin plate should be used with an interfragmentary pin that penetrates the ulnar corner fragment and is directed proximally and slightly radially to engage the volar cortex of the shaft proximally. Like any plate placed dorsally along the ulnar border of the radius, a 15-degree torsional bend should be added proximally to the plate to match the twist of the dorsal surface of the radial shaft. In addition, the ulnar pin plate may also be used for fixation along the central or radial aspect of the dorsal wall.

Dorsal wire forms (buttress pin, small fragment clamp, and combined wire forms) are prebent 0.045-inch K-wires designed for stabilization of dorsal and free articular fragments. These implants are easily adapted for variations in the size and location of independent fragments. The buttress pin can be simply inserted like a clip and then used as a joystick to reduce and fix a dorsal fragment. Alternatively, the buttress pin can be easily applied through a dorsal defect behind free articular fragments to sandwich them against the proximal carpal row. Other dorsal wire forms include the small fragment clamp that can grab and stabilize dorsal wall fragments and the combination small fragment clamp/buttress pin that can address combined dorsal wall and free articular fragments. These implants may be supplemented with dorsal bone graft to provide additional support behind the distal articular surface.

The volar buttress pin is an implant that is designed for unstable fragments that involve the volar rim. Fragmentation of the volar rim is usually the result of either a volar shear or axial loading mechanism. If the volar rim fragment is small, plate fixation can be inadequate; flexion or axial loading of the wrist can cause this fragment to displace over the edge of the plate, carrying the carpus with it into the palmar soft tissues. Alternatively, if the volar rim fragment is dorsiflexed with a depressed teardrop angle, plate fixation may further aggravate the angular deformity by pushing up on the volar surface of the fragment. The volar buttress pin is often a simple, effective solution for these complicated problems. Like the dorsal buttress pin, the legs of the volar buttress pin can be driven like a clip into the volar rim fragment and the implant then used as a joystick to manipulate and correct the position and angular deformity of the fragment. Once reduction is achieved, the wire form is simply fixed proximally with two screws and washers or a small wire plate.

Fragment-specific implants can also be used to treat certain types of distal ulna fractures when indicated. The ulnar pin plate can be used to stabilize displaced fractures through the base of the ulnar styloid or ulnar head. Wire forms can also be used when indicated on the ulnar side.

Of course, it is possible to augment standard volar or dorsal plating techniques with fragment-specific implants when needed. For instance, a dorsal wire form can supplement a fixed-angle volar plate by securing an unreduced or unstable dorsal or free articular fragment. As another example, a radial column plate can be used as supplemental fixation to a volar plate to add stability to a radial column fragment or to push the distal fragment radially to close the DRUJ.

Fragment-specific fixation has the flexibility to address many different types of fracture patterns. Initially, this simple ability to mix and match implants to the characteristics of the fracture may seem a bit overwhelming. However, fragment-specific fixation is really nothing more than a complete set of tools that has the capability to address a variety of different fracture patterns. For many patterns, there are standardized algorithms that can be used for treatment and will be discussed in the next sections.

Surgical Approaches

Radial Palmar Exposure

The surgical approach to apply a radial pin plate and volar buttress pin can be called “radial palmar” not only because of the implant locations but also because of the incision (Fig. 12-3). Typically, a 7-cm linear incision is made on the “radial palmar” aspect of the distal forearm, extending proximally from the level of the radial styloid.¹¹ The incision is about halfway between the true midlateral line of the forearm and its palmar surface. Another way to situate the incision is to feel the radial artery pulse and make the incision a little radial to this landmark.

FIGURE 12-3 Radial palmar incision. A, Initial exposure with incision between the radial artery and the first dorsal compartment tendons. The tip of a tenotomy scissors is placed along the superficial surface of the first dorsal compartment sheath proximally and swept distally to elevate a skin flap that includes the sensory nerves along the radial border of the wrist. B, Completion of the radial column exposure by releasing the first dorsal compartment sheath proximally, leaving the distal 1 cm intact and reflecting the insertion of the brachioradialis. APL, abductor pollicis longus; EPB, extensor pollicis brevis; ECRL, extensor carpi radialis longus; ECRB, extensor carpi radialis brevis. Inset, Surgical photograph with radial pin plate applied through radial palmar incision.

Longitudinal blunt dissection is carried out through the subcutaneous fat, and the numerous branches of the radial sensory nerve and the termination of the lateral antebrachial cutaneous nerve are identified and retracted. Although some patients may have quite a network of large and small sensory branches, these nerves can be retracted safely while still gaining adequate exposure to reduce and stabilize the fracture. Keep in mind that whenever K-wires or drill bits are used, soft tissue guides must be employed to prevent inadvertent damage to these sensory nerves (or other soft tissues structures).

The first extensor compartment is next identified and released to mobilize the abductor pollicis longus and extensor pollicis brevis tendons either dorsally or palmarly for exposure of the fracture segments. The extensor pollicis brevis usually has a separate subsheath that can be released. It is prudent to leave the last centimeter or so of the first extensor compartment sheath intact to reduce the likelihood of tendon subluxation postoperatively. The first compartment extensor tendons can be retracted dorsally, which will allow easy visualization of the brachioradialis tendon as it inserts at the base of the radial styloid in the midlateral plane.

The brachioradialis should be released for two reasons. Its insertion obscures access to the radial column fracture site and it must be released completely to allow mobilization of this segment. Additionally, the brachioradialis produces a deforming force on the radial column fracture and release of this tendon insertion reduces the tendency for subsidence of the fracture. The brachioradialis insertion becomes the floor of the first extensor compart ment, and at the margins of the radial styloid prominence it blends into the first extensor compartment tendon sheath.

Once the brachioradialis has been released, dissection should be directed at the palmar side of the first extensor compartment’s palmar sheath. Dissection should hug the palmar surface of the tendon sheath and stay radial to the radial artery, which is within a centimeter of the sheath, running parallel. The radial artery runs adjacent to the incision’s ulnar margin, although at the distal part of the wound the artery starts to angle toward the base of the thumb metacarpal; and, for this reason, care should be exercised when dissecting in the distal part of the incision, where the artery starts to run across the incision line rather than parallel to it. As dissection proceeds toward the radial styloid’s cortical surface, the artery and the radial insertion of the pronator quadratus can be swept ulnarly. It is possible to use a blunt elevator to expose the radial styloid and the entire palmar surface of the distal radius. A wide blunt retractor is ideal to safely retract the pronator quadratus, the median nerve, and flexor tendons palmarly and ulnarly so that the entire radial and palmar aspect of the distal radius can be visualized directly.

Closure of the wound is accomplished via suturing the subcutaneous layer and skin closure. Care should be taken to protect radial sensory nerve branches from entrapment during closure. The first extensor compartment tendons are allowed to return to their native positions, but repair of the tendon sheath is unnecessary. It should also be noted that repair of the brachioradialis is similarly not warranted.

Dorsal Exposure

Access to the dorsal aspect of the distal radius is required to address dorsal wall and ulnar corner fragments, as well as impacted free articular fragments. A dorsal exposure can also be used to aid in the reduction of particularly impacted radial styloid fragments or help elevate and use bone grafts in depressed articular segments. The dorsal incision is longitudinal and typically 5 cm long, located about 1 cm radial to the ulnar head and ending about 1 cm distal to the radiocarpal joint line (Fig. 12-4). Although there are fewer sensory nerves deep to this incision compared with the radial palmar region, care should be taken to pursue blunt dissection until the extensor retinaculum is encountered. There are usually a few large veins that can be either retracted or cauterized. The retinaculum overlying the fourth extensor compartment is next opened longitudinally, and the common digital extensor (and extensor indicis proprius and extensor digiti quinti) tendons can be retracted ulnarly to expose the dorsal metaphyseal area. The extensor pollicis longus should be mobilized by releasing the retinaculum proximally in a longitudinal fashion; often the retinaculum overlying Lister’s tubercle can be left in place and the extensor pollicis longus can be satisfactorily retracted radially. Occasionally, it can be helpful to fully release the extensor pollicis longus from Lister’s tubercle, thereby allowing it to be retracted farther radially. This is particularly helpful when the dorsal wall fragment extends radially and involves Lister’s tubercle as part of the fracture pattern.

FIGURE 12-4 Dorsal incision. Longitudinal incision is made dorsally and extends about 1 cm beyond the distal border of the radius. Retinaculum is incised over the fourth dorsal compartment. Inset, Dorsal incision showing placement of ulnar pin plate and dorsal buttress pin.

Exposure of the dorsal fracture fragments requires patience and attention to detail. Although this part of the surgery does not need to take more than 10 minutes, two critical issues must be addressed to allow placement of the appropriate hardware. First, the soft tissue around the dorsal fragments must be released enough to enable both good direct visualization as well as adequate mobility of the individual fragments so that they can be reduced. Use of a small elevator is helpful to pry apart any hematoma, incipient fracture callus, and periosteal attachments so that dorsal fracture pieces can be clearly identified. Sometimes it is even necessary to free up the retinacular extensions of the second compartment tendons (wrist extensors) as well as transpose the extensor pollicis longus radially so that the dorsal wall and region around Lister’s tubercle can be more easily treated.

The second critical issue relating to the exposure of dorsal fracture segments relates to identifying the proximal fracture perimeter. Fragment-specific fixation implants depend on a base of fixation that is anchored in the solid cortical bone proximal to the fracture; with the dorsal exposure, the shaft of the radius proximal to all fracture lines must be accessible. This can be facilitated by placing a narrow Hohmann retractor in the radial aspect of the wound, wrapping around the proximal, radial margin of the radial shaft. This maneuver will nicely demonstrate the step-off between the shaft of the radius and dorsal fracture fragments, which are usually buckled into each other and elevated dorsally by hematoma and comminution.

The terminal sensory branch of the posterior interosseous nerve is easily seen running just ulnar along the base of Lister’s tubercle. Many surgeons will choose to intentionally transect this nerve at the most proximal margin of the wound to reduce the likelihood of developing a painful neuroma due to compression from either scar formation or metal implants.

Once fracture reduction and fixation have been accomplished, closure of the dorsal wound is routinely accomplished in two layers, with absorbable sutures for the subcutaneous fat layer followed by skin closure.

Fracture Patterns

Extra-articular Fracture

This is the typical “Colles’” pattern, which is a purely metaphyseal fracture that does not have a radiocarpal fracture extension. Whereas many fractures can be treated with a closed reduction and cast, this fracture type can benefit from internal fixation if there is palmar displacement or if dorsal displacement is significant and cannot be reliably controlled with other methods. Additionally, radial column shortening often occurs in older patients or when the initial injury mechanism includes axial loading; and if radial shortening progresses more than 5 mm, operative correction may be warranted in select cases.

Internal fixation of the metaphyseal fracture segment can be accomplished through a single, radial palmar incision. A secure construct and anatomical reduction can be achieved by using a radial pin plate and a volar buttress pin (Fig. 12-5). The radial pin plate restores radial column length, and the volar buttress pin prevents dorsal or palmar translation. The volar buttress pin also has the effect of anatomically reducing the thick cortical margin on the palmar surface of the radius, which helps resist the tendency for proximal subsidence of the metaphyseal segment. It should also be noted that a key effect of the radial pin plate is application of a medially directed vector on the metaphyseal segment, which not only aids in restoration of radial length but just as importantly reduces the DRUJ and allows the cortical perimeter of the distal radius to be anatomically reduced, adding stability to the whole construct. This fracture can be visualized like the top of a rectangular box that has been sawed off and the box top then slides a little sideways and has one or two sides overhanging the base. Exact realignment of the box top allows all four sides of the top to contact the base edges and provides four sides of support.

FIGURE 12-5 Extra-articular fracture fixed with a radial pin plate and volar buttress pin. A, Injury radiographs. B, Radiographs at 2 weeks with biplanar fixation with radial pin plate and volar buttress pin. Radial pin plate resists flexion and extension movements of wrist, maintains length to the radial border, and pushes distal fragment ulnarly to seat ulnar head within sigmoid notch. Volar buttress pin maintains orientation of the joint surface in the sagittal plane, resists radial and ulnar deviation, and helps to maintain length. C, Clinical appearance at 17 days after surgery.

The radial styloid and entire metaphyseal fracture piece (which are together just one piece) can be reduced with the aid of an elevator inserted into the fracture site. Once the metaphyseal part is reduced, a smooth 0.045-inch K-wire is drilled through the radial styloid tip and secured into the cortical bone of the radial shaft, proximal to the fracture site. Anchoring the wire into cortical bone is critical to creating a strong construct. A radial pin plate is then placed over the K-wire, with the tip of the plate situated at the tip of the radial styloid. Checking the plate’s position with intraoperative mini-fluoroscopy should confirm that the gentle curve of the radial pin plate matches the shape of the distal radius in the anteroposterior projection. Small adjustments may be necessary to situate the plate so that it exactly matches the contour of the radial styloid region. Bending the plate manually is usually not necessary and means that the plate is not seated correctly relative to the native curve of the radial styloid region. Additional proximal dissection of the brachioradialis is often required to allow the radial pin plate to sit on the cortical margin of the radial shaft in the midlateral line. Also, the placement of the radial styloid K-wire will determine where the plate sits at its distal tip. Having the wire situated too dorsally or too palmarly will cause the proximal end of the pin plate to ride off the radial shaft. The shape of the distal radius and, in particular, of the styloid region, can be misleading, because the styloid area looks quite prominent palmarly and there is a tendency to place the K-wire starting point too palmar. A good anteroposterior landmark is the first extensor tendon sheath. Placement of the K-wire exactly at the dorsal, outer margin of the tendon sheath’s dorsal slip will usually result in the radial pin plate being seated in the exact midlateral line of the distal radius. If the plate is situated correctly, the first compartment tendons will cross over the plate in its distal third, with the pin holes of the plate being dorsal to the tendons and the screw holes of the plate being palmar to them.

Once the pin plate is correctly located, it is fixed to the radius shaft by placing two screws proximal to the fracture site. These are 2.3-mm screws that are predrilled with a 1.75-mm drill bit. Careful attention is required to make sure that the screws gain good purchase in the far (ulnar) cortex of the radial shaft and that the screws are not exiting through a fracture line. Tightening of these screws will compress the plate to the radial column and, by buttressing the radial side of the fracture and pushing the metaphyseal segment medially, will restore not only radial length but also DRUJ congruity. The 0.045-inch K-wire is then trimmed with a wire cutter, bent 180 degrees at its distal end, and tamped proximally so that it engages another pin hole in the pin plate and resists backing out. The length of the wire should be cut so that when taking into account the process of terminally seating into the pin plate it will just penetrate the proximal cortical margin of the radius. Gaining a cortical “bite” proximally is an important feature that adds strength to the pin plate construct. A second 0.045-inch K-wire is then placed in a similar fashion by drilling it through one of the remaining open pin holes in the plate, thereby traversing the distal fracture segment a second time and also gaining a proximal cortical purchase. This wire is also trimmed, bent 180 degrees at its distal end, and advanced to sit flush against the surface of the pin plate.

At this point, additional fixation can be applied to the palmar surface of the distal radius. There are rare circumstances in which a single radial pin plate may suffice, but this would be suitable for a small radial shear type fracture (that usually exits at the radiocarpal articular margin). For a metaphyseal, extra-articular fracture, the fracture segment is better secured with additional fixation. Placement of an implant at 90 degrees to the plane of the pin plate will tremendously strengthen the entire construct and prevent the fracture from subsiding, reangulating, or translating. Given the strength of the radial pin plate, another plate on the palmar surface of the distal radius is typically not necessary. Use of a volar buttress pin will prevent the fracture from shifting but is simple to apply.

To apply the volar buttress pin, a 0.045-inch K-wire or the 1.75-mm drill is used to place two unicortical pilot holes in the palmar surface of the fracture segment, usually 10 to 15 mm apart. The axis of the drill should be angled with the tip pointing proximally to match the shape of the subcortical bone of the distal radius and the “teardrop” contour of the radial styloid. The two pilot holes describe a line segment that is near perpendicular to the long axis of the radius. A volar buttress pin of appropriate length is then situated with each leg placed into one of the pilot holes. The buttress pin can be handled with a needle holder or wire bending forceps. If necessary, it is simple to modify the contour of the curve of the wire form with the three-point bender to match the flare of the distal radius. The legs of the buttress pin usually have to be shortened a little and cutting the radial leg slightly shorter than the ulnar one facilitates placement of the buttress pin legs into the pilot holes one side at a time. The volar buttress pin is then pressed down against the palmar surface of the radius; fluoroscopy should confirm that in the lateral projection the shaped buttress pin matches the contour of the palmar cortex of the distal radius. The buttress pin is then fixed with a 2.3-mm screw and washer combination; often a second screw and washer is warranted to resist axial load on the implant. Firm fixation of the proximal loop of the implant should be obtained. When necessary, a blocking screw and washer rotated 90 degrees can be used just proximal to the proximal end of the implant to prevent shortening. Fluoroscopic assessment in the anteroposterior projection should show that the volar buttress pin legs are contained with the metaphyseal or subchondral bone, distal to the fracture line, and that the proximal extension of the buttress pin is situated over the radial shaft.

At this point, fluoroscopy can be used to recheck the fracture reduction and hardware placement. There should be no hardware prominent outside the cortical margins of the radius and full passive range of motion of the wrist in rotation, radial and ulnar deviation, and flexion and extension should be confirmed. Occasionally, bone graft can be applied after final irrigation of the wound, although often the reduction will be anatomical and secure enough that additional bone graft is unnecessary and has no place to reside.

As an alternative, extra-articular fractures may also be effectively treated with a radial pin plate along the radial column and dorsal fixation with either an ulnar pin plate or dorsal buttress pin (Fig. 12-6). Like the previous technique, these combinations also create a 90/90-degree construct. Either a second dorsal incision can be used, or both implants can be placed through a single dorsal incision by elevating a radial skin flap and supinating the forearm to gain access to the radial column.

FIGURE 12-6 Extra-articular fracture fixed with a radial pin plate and ulnar pin plate. A, Injury radiographs. B, Biplanar fixation with a radial pin plate through a limited radial palmar approach and an ulnar pin plate through a limited dorsal approach. C, Clinical appearance at 8 weeks after surgery.

Volar Shear Fracture

The volar shear fracture is sometimes also referred to as an anterior marginal fracture or a “volar Barton” fracture. An oblique fracture line starts at the radiocarpal articular surface and exits on the palmar cortex of the radial metaphysis. The “shear” fragment has the wrist capsule and the extrinsic ligaments attached to it, and the entire carpus may sublux palmarly as the shear fragment displaces. Stabilization of this fracture segment requires a palmarly situated support, and this can be accomplished with a plate or volar buttress pin. A plate may be more appropriate if the fracture line exits proximally enough that the fracture fragment is large. In this case, it is easy to place a fixed-angle plate so that the distal margin of the plate supports the shear fragment. Placement of locking pins or screws at the plate’s distal margin adds extra fixation to the shear fragment, although simply securing the plate to the palmar cortex of the radius so it can act as a buttress is the key mechanical feature that reduces this fracture pattern.

Sometimes the volar shear fragment will be very small, appearing more like a fracture through the very distal “lip” of the radius. In these cases, a volar plate can be awkward because the plate’s edge has to be exactly at the edge of the radiocarpal joint to capture the fracture piece. It is easier to use a volar buttress pin in these situations. Two pilot drill holes (using a 0.045-inch K-wire or the 1.75-mm drill bit) can be made in the fracture segment and the volar buttress pin legs then inserted into the fracture fragment. Again, cutting one leg slightly longer than the other simplifies placement by allowing each leg to independently engage a hole as it is inserted. By securing the proximal end of the volar buttress pin to the radius shaft with one or two screw/washer constructs, the volar buttress pin can easily capture and reduce the marginal shear fragment.

Dorsal Shear Fracture

The dorsal shear fracture, or posterior marginal fracture, is equivalent to a “dorsal Barton” fracture and requires stabilization from the dorsal side (Fig. 12-7). Through a dorsal approach, this fracture can be secured by using an ulnar pin plate, or if the fracture segments do not extend too far proximally, a variety of wire forms can be applied to reduce the fracture. It is critical to gain solid purchase in good bone proximally, so if the fracture segment is large a pin plate (or even two pin plates) may be a better choice.

FIGURE 12-7 Dorsal shear fragment fixed with an ulnar pin plate and dorsal buttress pin. A, Injury radiographs. B, Internal fixation with an ulnar pin plate and dorsal buttress pin. Because of the uninvolved volar rim, the ulnar pin plate in this case could be used as a simple dorsal buttress plate.

A dorsal shear component is often associated with many axial loading injuries with intra-articular involvement. In these more complex fracture patterns, other components of the fracture can divert attention from the dorsal pathological process, and it is possible to easily miss the dorsal subluxation of the carpus on the lateral projection of the wrist. It is important to check intraoperatively that the dorsal margin of the distal radius is stable and reduced. Any significant dorsal subluxation requires reduction and stabilization and typically mandates a dorsal exposure. Although it is possible to capture the dorsal fragment with locked screws anchored in a palmarly situated plate, the dorsal fragments are often comminuted and are characterized by thin cortical margins. Dorsally located wire forms or pin plates have a much better mechanical advantage in holding down the shear component, thereby reducing the carpus back into a normal position relative to the forearm axis.

Radial Shear Fracture

A pure radial shear fracture corresponds to the “chauffeur’s fracture” eponym, in which the fracture line starts at the radial carpal margin and exits via an oblique path through the radial column cortex. This fracture can be associated with a carpal ligamentous pathological process, most commonly a scapholunate dissociation. The radial styloid fracture segment can be directly visualized through the radial palmar exposure and easily reduced using a radial pin plate. If the styloid segment is small, a three-hole radial pin plate may be all that is required. More commonly, however, the radial styloid involvement extends 2 cm more proximally and a five-hole radial pin plate affords better security. Whereas a pure radial shear pattern is not particularly common relative to the other more comminuted fracture patterns, if the radial styloid piece is indeed the only fracture segment present, then use of a single radial pin plate is all that is necessary.

Three-Part Articular Fracture

Three-part articular fractures are common low-energy injuries that are the result of a combination of dorsal bending and axial loading mechanisms. These fractures are characterized by a large radial column fragment and a smaller fragment at the ulnar corner of the dorsal radius. Although treatment with a fixed-angle volar plate is often effective, at times it is not adequate to reduce or stabilize the ulnar corner fragment. Fragment-specific fixation, on the other hand, provides a simple, direct approach that allows fixation of both radial column and dorsal fragments.¹² In addition, the fragment-specific approach to this pattern often requires a much more limited surgical exposure with less soft tissue dissection and is particularly appropriate for younger patients with higher functional demands.

The combination of a radial pin plate with either an ulnar pin plate or dorsal buttress pin is the most common fragment-specific approach for the treatment of three-part articular fractures (Fig. 12-8). Typically, this is done through a two-incision approach, using the radial palmar incision for application of the radial pin plate and a limited dorsal incision for applying the buttress pin or ulnar pin plate. Alternatively, this pattern may be approached through a single dorsal incision by elevating a subcutaneous flap radially and supinating the forearm to gain access to the radial column.

FIGURE 12-8 Three-part fracture treated with radial pin plate and dorsal buttress pin. A, Injury radiographs. B, Radiographs at 1 month show fixation of radial column with radial pin plate and simple fixation of ulnar corner with dorsal buttress pin.

Complex Articular Fracture

Complex articular fractures are ideally suited for the fragment-specific approach (Figs. 12-9 and 12-10). The key to fractures with many pieces is that the reduction is achieved in little steps. Reduction and fixation of one part will have an influence on the ability to reduce another fragment, and, consequently, some “tweaking” of the reduction is required. The entire distal radius is like a puzzle that has several interlocking pieces, and sometimes it is necessary to alternate between different fracture pieces and “nudge” the reduction in different spots until the whole radius can be anatomically puzzled back together.

FIGURE 12-9 Multipart articular fracture fixed with radial pin plate, volar buttress pin, and ulnar pin plate. A, Radiographs after attempted closed reduction. B, Intraoperative films. B1, Note displacement of an independent volar rim fragment after stabilization of the radial column and dorsal fragments, with depression of the teardrop angle, increase in the anteroposterior distance, and a nonuniform joint interval. B2, Application of volar buttress pin with reduction of the volar rim and restoration of the anteroposterior distance, teardrop angle, and a uniform joint interval. C, Final postoperative radiographs.

FIGURE 12-10 Highly comminuted intra-articular fracture pattern. A, Injury radiographs reveal presence of radial column, dorsal wall, ulnar corner, and volar rim fragments. Note outline of teardrop with depressed teardrop angle and dorsal subluxation of the carpus. There is a new fracture through the base of the ulnar styloid in addition to a preexisting ulnar styloid nonunion. B, Radiographs at 2 months after fragment-specific fixation.

The radial palmar exposure is accomplished first, with release of the brachioradialis to help relax its deforming force on the radial styloid. Release of the radial insertion of the pronator quadratus will allow exposure of the palmar aspect of the radius, so that the palmar marginal cortex and the “teardrop” area can be fully inspected and manipulated. It is often helpful to reduce the radial styloid fragment with respect to length and angulation and then provisionally pin it in place with a single 0.045-inch K-wire placed through the tip of the styloid and anchored proximally in unfractured cortical bone. If a volar rim fragment is present, it is usually stabilized next.

Next, the dorsal exposure is achieved and the ulnar corner fragment is identified, cleaned, and reduced. It is important to properly reduce this fragment because bringing it back out to length will have the effect of restoring the correct palmar tilt to the distal radius. Sometimes, manipulation of the ulnar corner will need to be performed together with reduction of the dorsal wall fragment (if a dorsal wall fragment is also present). When the ulnar corner fragment is reduced, a 0.045-inch K-wire should be drilled through its most distal and ulnar edge from the dorsal side. The K-wire needs to be directed proximally, palmarly, and somewhat radially, so that it engages cortical bone on the palmar radial shaft proximal to the fracture site. An ulnar pin plate (either three or five hole) is then placed over the K-wire and fixed to the dorsal surface of the radius. The plate can be twisted slightly with wire bending forceps so that it sits flush with the dorsal surface of the radius. Two screws (2.3-mm diameter) are used to fix the ulnar pin plate proximally, and then the K-wire is trimmed for length, bent over, and advanced so that it sits flush in the two most distal pin holes of the plate. If room allows, a second K-wire is then drilled through another open hole of the pin plate and similarly trimmed to length and bent over so that it engages two pin holes of the plate. Alternatively, the tips of the K-wires may be trimmed directly through the volar incision. Both K-wires should be just long enough that their proximal tips engage cortical bone of the radial shaft.

Fluoroscopy can be used to check hardware position and reduction of the ulnar corner. Particular attention should be paid to assessing the congruency of the DRUJ. Once the ulnar corner has been reduced, attention can be returned to the radial styloid region. The provisional K-wire previously placed can be removed and relocated so that it is exactly in the tip of the radial styloid. A radial pin plate (usually five-hole length) is then placed over the K-wire and seated along the midlateral aspect of the radial column. By securing the plate with two 2.3-mm screws, it will push the radial styloid not only distally (restoring length) but also ulnarly, which has the effect of closing down any articular surface gaps and additionally restoring the correct inclination angle to the distal radius.

An alternative to fixation of dorsal wall or dorsal ulnar corner fragments is to use a dorsal buttress pin for fixation of larger fragments. In this technique, the fragment is reduced and two 0.045-inch K-wires inserted through the fragment parallel to the joint surface. The position and orientation of these pilot K-wires can be checked by initially placing a buttress pin upside down on the dorsal surface so that the legs point vertically up off the bone. The position and orientation of the legs is noted, and the pilot K-wires are inserted and checked with fluoroscopy. The buttress pin can then be contoured to fit any dorsal curve and the legs cut, leaving one leg longer than the other. The pilot K-wires are individually withdrawn and replaced with a corresponding leg of the buttress pin, and the wire form is fully seated. The buttress pin is secured proximally with one or two screws and washers or a small wire plate.

Any other fragments that are not reduced at this point can now be addressed. Sometimes a dorsal wall fragment will be present, which can be stabilized with a small fragment clamp (wire form). Sometimes the third fragment will be the palmar ulnar corner, which can be buttressed upward with a volar buttress pin (secured with a proximal screw and washer). Restoration of the radial column can be performed as an intermediate step, after definitive fixation of the ulnar corner, or the radial column fixation can be reserved as a final maneuver, after stabilization of both the ulnar corner fragment and whatever other articular fragment is present.

The technique of fragment-specific fixation is characterized by some inherent “tinkering” with the fracture fragments and the hardware. The nature of multifragmented articular fractures is such that anatomical reduction of the entire distal radius requires puzzling little pieces back together, and sometimes a perfect reduction of one fragment will actually preclude another piece from being seated into place. Consequently, it may be necessary to make minor adjustments, alternating between individual pieces, so that the entire construct can be eventually reduced perfectly. It may be necessary, for example, to back out the radial styloid K-wire while reducing the ulnar corner if the K-wire blocks the ability of the ulnar corner fragment from being fully reduced. Similarly, if the ulnar pin plate is not holding the ulnar corner and/or the dorsal wall fragment fully out to length, the radial styloid fragment will not reduce properly when the radial column is addressed. Although the fracture-specific fixation method is characterized by a stepwise approach to the distal radius fracture, making numerous, alternating adjustments throughout the course of the surgery is essential to ultimately achieving an anatomical reduction of all the individual fracture fragments.

Volar Rim Fragment

A particularly challenging fracture fragment is the volar rim fragment along the palmar ulnar corner of the radius. This fracture segment is in the exact opposite position from the dorsal ulnar corner fragment. It is less common and typically has a square footprint that can be seen through the radial-palmar exposure. It can be readily stabilized because its palmar surface is thick cortical bone. Malposition of this fragment has the same implications as malposition of the dorsal ulnar corner: incongruity of the DRUJ and loss of forearm rotation. In addition, failure to stabilize this important fragment can result in progressive displacement with palmar subluxation of the carpus.

Visualization of the palmar corner fragment is best achieved by using a blunt, narrow retractor via the radial palmar exposure. This fracture fragment can be stabilized using a single volar buttress pin, although drilling the pilot holes in the fragment (for seating the volar buttress pin legs) can be difficult. Use of a soft tissue guide while drilling is mandatory, and sometimes making a separate small incision ulnar to the median nerve can be helpful. Careful, blunt dissection through a 1-cm incision, located longitudinally between the median nerve and ulnar neurovascular bundle, can be used to place the soft tissue sleeve to more easily drill two holes into the palmar corner fragment. Firm fixation of the volar buttress pin with two screws and washers is needed to avoid shortening of this fragment; when needed, a blocking screw and washer rotated 90 degrees in line with the wire form can help prevent sliding.

Ulnar Styloid Fracture

Whether an ulnar styloid fracture merits fixation is a topic beyond the scope of this chapter. If it is decided to internally fix this piece, it can be easily accomplished using the “ulnar sled” or a three-hole ulnar pin plate. Either of these fixation constructs is easy to apply and provides rigid fixation of the styloid.

Exposure of the ulnar styloid is accomplished through whichever method the surgeon prefers. The styloid itself can be stabilized by drilling two small holes in its tip with a 0.045-inch K-wire and then sliding the legs of the ulnar sled down into these holes. The outer wire margin of the ulnar sled can then be fixed to the ulnar neck with a single screw and washer. Alternatively, if an ulnar pin plate is used, a 0.045-inch K-wire is first drilled through the tip of the styloid fracture, anchoring the proximal tip of the K-wire in the cortical bone of the ulnar shaft or neck. The tip of the plate is bent 90 degrees and the distal most pin hole of a three-hole ulnar pin plate is then placed over this K-wire. The plate is fixed to the ulnar cortex using one or two 2.3-mm screws.

Implant Fixation: Technical Tips

The fragment-specific approach is characterized by making multiple small adjustments, and some technical pointers may be helpful. First, soft tissue drill sleeves should always be used when drill bits or K-wires are placed to avoid wrapping up tendons or superficial nerves. Having two such drill sleeves available makes their use convenient and timely and thereby makes it less likely that this important safety step will be skipped. A narrow blunt retractor (e.g., Army-Navy) is particularly useful in safely retracting the palmar soft tissues (including the median nerve and flexor tendons) when exposing the palmar aspect of the distal radius. Careful use of this retractor will allow visualization of even the most medial aspect of the palmar distal radius.

K-wires specifically designed for use in fragment-specific fixation have stripes on them, marking every 5 mm. Paying close attention to the stripes will allow precise placement of the K-wires so that, at final implantation, they are long enough to engage proximal cortical bone but short enough that they do not protrude too far. Note that K-wires placed through the dorsal approach that protrude palmarly, can not only be felt but can also be seen through the radial palmar incision. By using an end-cutting wire cutter, it is a simple matter to trim off the prominent end of such a K-wire through the radial palmar incision, which precludes having to remove the K-wire and start over. Be sure to keep track of the trimmed wire end; it has a tendency to fly off the wire cutter jaws and embed itself in the pronator quadratus muscle belly.

When placing the radial pin plate, the insertion point for the trans-styloid K-wire is crucial. If this K-wire is placed too dorsally or too palmarly, it will cause the radial pin plate to sit improperly on the midlateral aspect of the radial shaft. This will not only change the force vector applied by the pin plate so that it does not push the radial styloid fragment medially but also make it likely that the proximal end of the plate will not sit on the radial shaft and make it impossible to secure with cortical screws. The anchoring K-wire for the radial pin plate should be in the midlateral plane, and location of this exact plane can be difficult owing to the irregular shape of the distal radius. A good landmark for placement of this K-wire is the periosteal attachment of the dorsal sheath of the first extensor compartment. Additionally, if the radial pin plate is seated properly, the first compartment tendons will pass over it obliquely, with the pin holes of the plate being located dorsal to the tendon pathway and the proximal screw holes of the plate lying underneath or just palmar to the tendons.

When bending K-wires to terminally implant their distal ends into pin holes of a pin plate, it can be useful to overcrimp the K-wire, thereby creating a hook effect that helps the wire “lock” into two adjacent pin holes. This creates extra grip for the K-wire and reduces the likelihood of loosening in the postoperative period.

Securing a volar buttress pin with a single screw and washer can be sufficient to hold reduction of a particular fracture segment. However, if the piece being held is large or is preventing the entire carpus from subluxing, consideration should be given to using two screw/washer constructs or placement of a screw proximal to the wire form (in the manner of a “blocking screw”) so that the wire form cannot slide proximally.

Depressed articular segments can be nicely elevated and held in place using buttress pins, either from the dorsal or palmar side. However, it is prudent to add cancellous bone graft in the subchondral zone, which will help reduce fracture resorption and resist the tendency for subsidence. Remember that the patient’s premorbid bone quality as well as the degree of comminution will have a major influence on the tendency for collapse of bone, and bone graft should be added liberally when needed.

Sometimes adjustments need to be made to the radial styloid reduction after a radial pin plate has already been secured to the shaft of the radius. These situations often relate to improving the radial column length a little bit more after other fracture segments have been reduced. Instead of removing the radial pin plate and starting over, a helpful trick can be to simply remove the distal K-wires from the pin holes, manually apply traction to restore length of the radial column, and re-drill new K-wires directly through pin holes. This method can also be used to make minor adjustments in the rotation or palmar tilt of the radial styloid.

In addition to the specialized wire-bending forceps, K-wire bending pliers, and wire impactors that typically come with fragment-specific fixation implant trays, there are other commonly found operative instruments that will aid in managing difficult distal radius fractures. Straight and curved small curets are useful for manipulating fracture voids, removing fracture debris, and applying bone graft. Dental picks as well as narrow impactors are invaluable for mobilizing and holding tiny cortical fracture fragments. An “end-cutting” wire cutter is useful for trimming K-wires that have already been implanted but protrude a little too far on the palmar surface of the radius.

Postoperative Care

Immediately after wound closure, a soft dressing is applied over the incision and the patient placed into a removable volar brace. Alternatively, the forearm can be placed into a forearm-based plaster splint that does not limit elbow motion and stops short of the distal palmar crease to allow full finger motion. If a plaster splint is used, this is converted at day 3 to a Velcro-type wrist splint, but patients are instructed that it is a “transitional” device to help them feel safe when they are out of the home for the first week. They are specifically encouraged not to wear it when sleeping or pursuing simple household activities. Occupational therapy can be started on postoperative day 3, and most patients are encouraged to stop at the hand therapy clinic before going home from the first dressing change.

Therapy orders specify active and careful passive motion of the wrist joint in all planes, and immediate elbow and finger motion is mandatory. Patients tend to have significant dorsal hand swelling, especially if both a radial palmar and a dorsal incision were required, although swelling typically improves dramatically within the first week. Recovery of forearm rotation can be accomplished almost immediately, and this provides enormous functional benefits that tend to facilitate early recovery of wrist motion in the other planes.

Patients are directed to attend therapy sessions twice per week. In addition to a dressing change on postoperative day 3, office visits are scheduled on postoperative day 10 for suture removal and then once every 2 weeks thereafter until their motion and function have reached 85% of normal. This goal is typically reached within the first 6 weeks after surgery.

Complications

Injury to normal structures is always a possibility in any operation, especially during surgical exposures that are in close proximity to nerves and arteries.¹³ It is important to carefully protect the radial artery and vein during the radial-palmar approach and be aware that the artery crosses obliquely over the distal portion of the incision. Although release of the arm tourniquet is rarely necessary before wound closure, if the artery or any of its small branches are particularly troublesome to mobilize, release of the tourniquet to check for bleeding may avoid a postoperative hematoma.

The radial sensory and terminal branches of the lateral antebrachial cutaneous nerves have numerous branches that need to be retracted or mobilized during the initial part of the radial-palmar approach. Although it is quite common for patients to note a “strip” of numbness along the midlateral wrist ending at the dorsal aspect of the thumb metacarpal, this numbness tends to resolve by itself within a few months and requires no treatment. Development of a painful, radial sensory neuroma is possible but extremely uncommon.

When both the radial palmar and dorsal incisions are required, it might seem as though the incisions could produce local ischemia to the soft tissue island between them. In reality, this problem has never been reported, although it is prudent to make sure that the radial palmar and dorsal incisions are longitudinal and meticulously located so that they are almost 180 degrees apart relative to the diameter of the wrist. It is probable that the close location of the radial artery and its branches to the radial palmar incision creates a zone of vascularity that adds an extra margin of safety for soft tissue viability.

Despite the location of the radial pin plate under the first compartment extensor tendons, symptomatic tendinitis related to this pin plate is very rare. Occasionally a K-wire loosens and starts to back out, causing pain and prominence in the skin. Being meticulous about K-wire length and making sure that the proximal end of the K-wire fully engages cortical bone will prevent loosening. Additionally, it is possible to overbend the distal tip of the K-wire so that when it engages the pin plate through two adjacent pin holes, the K-wire actually grips tightly between the pin holes and strongly resists loosening. In cases where K-wires have loosened and become symptomatic (typically from the radial pin plate), they can usually be removed easily in the office setting.

The screws used to anchor pin plates and wire forms are self tapping, and, consequently, if they are prominent, the sharp cutting tips can potentially injure soft tissues. In particular, if self-tapping screws are placed on the palmar side of the radius and the sharp tip protrudes dorsally, it is theoretically possible to erode and rupture any of the digital extensors. Careful attention to screw length will prevent this. K-wires should be trimmed to length so that they protrude modestly past cortical margins but not enough to be externally palpable or irritate local structures.

Release of the carpal tunnel at the time of fracture fixation is rarely indicated. However, if the patient has pronounced median paresthesias before surgery, then a carpal tunnel release coincident with fracture surgery may be prudent. Patients who present with preoperative symptoms of median nerve compression often have high-energy injuries or fracture patterns that either impale the median nerve or stretch it over severe palmar angulation. It is certainly worthwhile to look for any median nerve pathology while obtaining the preoperative history and physical examination so that clues to median nerve compromise can be identified ahead of time. The radiographic appearance of the fracture before initial closed reduction attempts and the mechanism of injury can also be valuable predictors of potential median nerve compromise.

One simple cause of loss of reduction may be simply related to failure to recognize a major fracture component. Carpal subluxation or shortening can occur either on the dorsal side from a dorsal wall or ulnar corner fragment that is left untreated or on the palmar side from a missed volar rim fragment. Careful evaluation of radiographs both at the time of injury as well as during operative stabilization can help identify major components of the fracture pattern so that major sources of instability are not missed.

Clinical Outcome Data

There have been only a few published reports regarding the outcome of fragment-specific fixation to date. Use of fixed-angle plates as the sole implant to stabilize comminuted distal radius fractures has gained popularity, and good results have been reported.¹⁴ Use of a fixed-angle plate as the only approach to distal radius fractures is certainly attractive due to the simplicity of operative planning and ease of application. A prospective, controlled study directed comparing the surgical morbidity and clinical outcomes of comminuted intra-articular fractures treated with fixed-angle plates and a fragment-specific approach has not yet been published, and these types of studies would be needed to clearly advocate one method over another.

Some authors, however, have noted that the stability of highly comminuted distal radius fractures depends also on reduction and fixation of smaller fragments in addition to the major fracture segments.¹⁵ Additionally, biomechanical studies have demonstrated that pin plates, wire forms, and K-wires as used in a fragment-specific approach are more stable than K-wire–supplemented external fixation.¹⁶ Using cadaver models, Taylor and coworkers showed that fragment-specific constructs were comparable in strength to fixed-angle plates and that ulnar corner fractures of the distal radius were much better addressed via a fragment-specific approach.¹⁷ Grindel and coworkers showed that fragment-specific implants used with a fixed-angle plate provided a stronger construct than use of a fixed-angle plate alone.¹⁸ In addition to the biomechanical evidence supporting the stability of fragment-specific fixation, it should also be realized that comminuted distal radius fractures present with a wide variation in stability and fracture geometry and that a fragment-specific approach uniquely enables internal fixation to be tailored to the exact needs of the fracture.

Konrath and colleagues reported on 27 patients with a 2-year minimum follow-up treated by fragment-specific fixation.¹⁹ Pin plates and various wire forms were used in all patients. There was a high level of patient satisfaction, and only one fracture lost reduction; there were no tendon ruptures. Schnall reported on two groups of patients treated with fragment-specific fixation.²⁰ Group 1 consisted of 20 patients with high-energy trauma, and group 2 consisted of 17 patients treated at another institution. Average time to return to work in group 1 was 6 weeks and all fractures united. In group 2, there was no significant loss of reduction and grip strength averaged 67% that of the contralateral limb.

A research group for one of the authors (L.S.B.) recently performed a retrospective evaluation of 81 patients, representing 85 intra-articular distal radius fractures, with a minimal follow-up of 1 year (mean follow-up, 32 months).²¹ All patients were treated with fragment-specific fixation and were evaluated at final follow-up with physical examination, repeat radiographs, and outcome scoring according to Gartland and Werley as well as a Disabilities of the Arm, Shoulder, and Hand (DASH) outcome survey. Patients were allowed to start motion in the immediate postoperative period and underwent supervised occupational therapy for at least the first month after surgery.

Within the first 6 weeks after operation, 62% of patients achieved a 100-degree arc of motion in the flexion/extension plane as well as normal forearm rotation. Comparison of radiographs between final follow-up and immediately after surgery demonstrated that fracture alignment was maintained and that no cases of post-traumatic arthritis had developed. The average DASH score was 9 and, using Gartland and Werley scoring, 61% of patients had excellent and 24% had good results. Grip strength of the operated side recovered to 92% of that of the uninjured side and the flexion/extension range of motion of the fractured wrist, when compared with the normal side, averaged 85% and 92%, respectively. Analysis of the fracture reductions obtained with the fragment-specific approach showed that palmar tilt was on average within 4 degrees of the normal side and that ulnar variance changed on average by 1.2 mm. Average changes for radial height and inclination angle were within 1 mm and 1 degree of the uninjured side, respectively. Articular congruity was unchanged. There were no infections or complications relating to nerve, artery, or tendon injuries. Several patients required a second operation to address symptomatic hardware; overall, the rate of hardware removal after the primary procedure was 6%. One patient required a second operation 9 months after the primary procedure to perform a distal ulna resection to address painful forearm rotation.

The clinical experience from the other author (R.J.M.) is quite similar. Over an 8-year period, 187 unstable distal radius fractures were treated with internal fixation; of these, 136 fractures had fragment-specific fixation. There were 24 A3 fractures (unstable bending injuries), 16 C1 fractures (three-part articular fractures), 4 shear fractures (AO type B2 and B3), and 92 comminuted articular fractures (AO type C2 and C3). In all but three patients, motion was started immediately after surgery. Resistive loading was not allowed until signs of radiographic healing was evident on follow-up radiographs. By 1 month, patients regained an average motion of over 80 degrees of flexion/extension arc, 60 degrees of supination, and 70 degrees of pronation. Finger motion returned rapidly. In addition, grip strength at 1 month averaged 50% of the uninvolved side, increasing to an average of 90% of the uninvolved side by final follow-up (Table 12-1).

TABLE 12-1 Fragment-Specific Fixation: Average Clinical Motion and Grip

Radiographs on these patients showed near-anatomical restoration of the joint surface, with correction of radiographic parameters postoperatively that remained essentially unchanged until union (Table 12-2). All fractures united. Three fractures had failure of fixation, and two patients had a dorsal extensor tendon rupture, although the cause of one tendon rupture was from an untreated but displaced dorsal fragment. Final DASH scores were 8 ± 10 for AO type A fractures, 30 ± 21 for displaced AO type C fractures with volar displacement, and 13 ± 18 for displaced AO type C fractures with axial or dorsal displacement (with a range from 0 to 100 with 0 being the best DASH score possible). Patient-Rated Wrist Evaluation (PRWE) scores were 1 ± 2 for AO type A fractures and 2 ± 2 for AO type C fractures (with a range from 0 to 10 with 0 being the best PRWE score possible) (Table 12-3).

TABLE 12-2 Fragment-Specific Fixation: Average Radiographic Measurements