Distal-Third Forearm Fractures

The dorsal metaphysis of the distal radius is subject to tensile and compressive forces during routine forearm activities. The volar surface transmits higher compressive forces. Stable reduction of a DRF requires that this biomechanical relation be reestablished. Accordingly, the volar buttress must be addressed first in unstable volar fractures (eg, volar Barton fracture, DRF with significant volar comminution).

In the presence of volar comminution or inherently unstable volar vertical shear fractures, the key to stable fracture reduction is to create a solid volar buttress either by accurate reduction of large volar metaphyseal fragments or by placement of a volar buttress plate. Once volar stability is restored, the dorsal metaphyseal fragments can be reduced against the stable volar buttress.

Restoration of volar stability also has important radiocarpal implications because the stout radiocarpal ligaments are attached to the volar surface. Therefore, volar integrity is critical for the following reasons:

• It allows reduction of dorsal metaphyseal fragments against a stable volar buttress
• It prevents possible radiocarpal instability

Studies have shown that DRFs often are associated with tears of the triangular fibrocartilage complex (TFCC), scapholunate ligament, and lunotriquetral ligament.[8, 9] Geissler et al found that intracarpal soft-tissue injuries occurred most frequently with fractures involving the lunate facet.[8] The lunate facet and its strong ligamentous attachments with the proximal carpal row and ulnar styloid form the medial complex of the distal radius as described by Melone (see the image below).[10] The carpus almost always is displaced with the palmar and/or dorsal lunate facet die-punch fragment of the distal radius because of the exceptionally strong ligaments of the medial complex.

Scapholunate dissociation can occur with severely displaced DRFs, and the lunate displaces with the medial complex (lunate fossa), while the scaphoid remains with the radial styloid. The scapholunate diastasis usually corrects with reduction of the medial complex. Most of the disrupted soft tissues of the scapholunate articulation can heal with a period of immobilization, and Melone had no cases of subsequent chronic carpal instability.[10]

Scapholunate and lunotriquetral ligament injuries can occur in minimally displaced extra-articular fractures and in severely comminuted intra-articular fractures. The presence of central perforations of the scapholunate ligament and tears of the short radiolunate ligaments has important implications. Although these injuries do not result in scapholunate instability, Richards et al found false findings on arthrograms in 8% of patients in whom arthrography rather than arthroscopy was used for diagnosis.[9]

With arthroscopy, it is difficult to evaluate injury to the volar extrinsic ligaments, including the radioscaphocapitate and long radiolunate ligaments, because these ligaments may be pulled taut with the longitudinal traction necessary for entry of the arthroscope.[8]

DRFs characterized by shortening and dorsal angulation are more likely to have a TFCC disruption, but preoperative radiographs have no predictive value in identifying specific interosseus ligament injuries. Intra-articular and extra-articular DRFs commonly are associated with ligamentous injuries and tears of the radial aspect of the TFCC; however, disruption of the ulnar insertion of the TFCC is uncommon. That certain intra-articular fracture patterns are associated with fewer TFCC injuries emphasizes the role played by the TFCC in force dissipation and stability after a DRF.[9]

In general, the authors do not treat carpal ligament injuries (including TFCC injuries) occurring in association with DRFs that do not show visible deformities on plain radiographs. The authors believe that with accurate fracture reduction, the ligaments heal during the postoperative or postreduction immobilization period. However, whenever an external fixator is applied, it must be used for neutralization only because excessive traction can displace or complete undiagnosed partial carpal ligament tears.

The typical mechanism of a dorsally displaced DRF is a fall on an outstretched hand. This type of injury results in tensile forces across the volar surface (compression side), compressive forces on the dorsal surface (tension side), and supination of the distal fracture fragment. In the young adult, DRFs are often caused by high-energy trauma. In the elderly patient, low-energy trauma, such as a fall from a standing height, can result in this injury.

Compression and torsion across the articular surface can cause various patterns of intra-articular displacement. Dorsal and palmar shear fractures of the medial complex are examples of compression applied to specific locations. Radial styloid fractures can be due to compression and/or torsion.

Fractures of the distal radius are not simple injuries and therefore require careful evaluation of the radiocarpal joint, the distal radioulnar joint (DRUJ), and the carpal bones. However, educated decision-making based on objective data and patient profile can lead to optimal outcomes of these challenging fractures.

The prognosis is dependent on the functional expectations of the patient; accordingly, anatomic restoration of the distal radius and early radiocarpal joint mobilization are important for patients with high functional demands.

In a study by Clayton et al, a high correlation was identified between bone mineral density (BMD) and the severity of DRFs.[11] In patients with osteoporosis, the probability of early instability was 43%; that of late carpal malalignment, 39%; and that of malunion, 66%. In patients with osteopenia, the probability of early instability was 35%; that of late carpal malalignment, 31%; and that of malunion, 56%. These findings compared with a 28% probability of early instability, a 25% probability of late carpal malalignment, and a 48% probability of malunion in patients with normal BMD.

Koenig et al evaluated whether early internal fixation or nonoperative treatment is preferred for displaced, potentially unstable DRFs with initial adequate reduction.[12] They found that internal fixation with a volar plate provided a higher probability of painless union for potentially unstable distal radius fractures. In most cases, long-term gain in quality-adjusted life years outweighed the short-term risks of surgical complications, making early internal fixation the preferred treatment. In patients older than 64 years, however, nonoperative treatment may be preferred because of lower disutility for malunion and painful malunion outcome states.

In postmenopausal women, detailed bone structure and strength measurements provide insight into the pathogenesis of forearm fracture, but femoral neck area BMD provides adequate measurement for routine clinical risk assessment, according to Melton et al.[7] Fracture cases had inferior bone density, geometry, microstructure, and strength. The factor of risk was 15% worse in patients with forearm fracture. See also the Fracture Index WITH known Bone Mineral Density (BMD) calculator.

On presentation, the history should include the patient's pertinent past medical history, occupation, hand dominance, mechanism of injury, and treatment history. The patient's dependence on the extremity for occupational needs and activities of daily living (ADLs) greatly affects later decision-making.

Start the physical examination proximally at the shoulder, and continue distally to include the elbow, wrist, and hand. Visually inspect the wrist, and note the presence or absence of open wounds, swelling, and deformity. Pain may limit manual examination and range of motion (ROM) of the injured wrist, but investigate other proximal injuries because they may alter the treatment plan. An adequate neurologic and vascular examination with particular attention to the median nerve is essential. Tests for compartment syndrome also must be performed carefully.

Initial radiographs of the distal radius should consist of good posteroanterior (PA) and lateral views. A good lateral view demonstrates that the anterior surface of the pisiform lies between the anterior surface of the capitate and the volar surface of the scaphoid tuberosity.

The standard plain radiographs are important because they show the extent and direction of initial displacement, along with information about the distal radioulnar joint (DRUJ). Additional information is obtained later with traction (reduction) radiographs that can help demonstrate whether the distal radius fracture (DRF) is intra-articular or extra-articular, and they can most readily reveal the degree of comminution. In addition to showing the degree of initial displacement, postreduction radiographs are extremely helpful for treatment planning.[2, 13, 14]

Measurements on the reduction radiographs should include the following (see the images below)[15] :

• Radial inclination (normal, 22°)
• Radial length (normal, 12 mm)
• Ulnar variance (normal, 0-1 mm)
• Volar tilt (normal, 11°)
• Articular stepoff
• Articular gap

The amount of acceptable articular stepoff is debated, but most authors believe that less than 1-2 mm is desirable. Although long-term functional outcome has not yet been correlated with magnitude of articular stepoff, the development of posttraumatic arthritis certainly has.

Radial length is the measurement along the longitudinal radial axis between the tip of the radial styloid and the articular surface of the ulna styloid. This length is influenced by radial inclination and ulnar variance.[16]  Thus, radial length indicates only the magnitude of longitudinal length discrepancy between the distal radius and ulna, not the specific cause.

Changes in radial inclination and radial shift can result from the multiplanar displacement of the DRF. Pronation or, more commonly, supination of fragments is a frequent deformity that is difficult to measure directly with standard radiographs. Ulnar variance is influenced by metaphyseal comminution and shortening, forearm position, ulnar-head fractures, and/or fracture displacement of the medial aspect of the distal radius. Comparison views of the contralateral uninvolved wrist may assist in the evaluation of complex DRFs.

On plain radiographs, stepoff and gap measurements can be imprecise for various reasons, including nonstandardized radiographic techniques, overlying radiopaque implants, soft-tissue shadows, and/or the complex structure of the distal aspects of the radius and ulna.[17]

Cole et al noted poor interobserver and intraobserver agreement in intra-articular stepoff and gap measurements on plain radiographs of acute DRFs. In the same study, 24% of the plain radiographic values indicated displacement of less than 2 mm, whereas computed tomography (CT) indicated that the displacement was more than 2 mm. Conversely, significant displacement (>2 mm) was noted on 6% of the plain radiographs but not confirmed by the CT readings.[18]

Plain tomography or CT in the sagittal and coronal planes parallel to the longitudinal axis of the radial shaft is extremely helpful in quantifying the displacement and direction of an intra-articular fracture. These techniques are also useful when the fracture pattern is difficult to visualize on plain radiographs. CT is strongly recommended for defining intra-articular fracture patterns, especially those associated with die-punch fractures, volar rim fractures, and fractures involving the scaphoid facet (which can be more difficult to assess on plain radiographs).[15]  The authors routinely obtain CT scans before operating on displaced intra-articular fractures.

Bedside ultrasonography (US) has been shown to be effective in the diagnosis of nonangulated distal forearm fractures in children and may develop into a more portable diagnostic tool helpful in emergency departments (EDs).[19]

Douma-den Hamer et al performed a systematic review and meta-analysis aimed at determining the diagnostic accuracy of US for detecting distal forearm fractures.[20] They found US to have a sensitivity of 97%, a specificity of 95%, a positive likelihood ratio (LR) of 20.0, a negative LR of 0.03, and a pooled diagnostic odds ratio (DOR) of 667, with the six-view method yielding higher specificity, positive LR, and DOR than the four-view method. The authors concluded that US is highly accurate for diagnosing distal forearm fractures in children when the proper viewing method is used and that it could be considered a reliable alternative to radiography in this setting.

Others have found point-of-care US (POCUS) to be useful for diagnosing distal forearm fractures in pediatric EDs.[21, 22]

Burstein stated that a classification system must suggest a method of treatment and provide a reasonably precise estimation of the outcome of that fracture. Furthermore, a classification system must have intraobserver repeatability and interobserver reliability.[23]

Although the Frykman system for classification of DRFs has been used extensively in the medical literature, this classification fails to identify the direction and extent of fracture displacement.[24]  As a result, other classification tools have been developed, such as the Association for the Study of Internal Fixation (AO/ASIF), Melone, and Mayo systems. These systems classify the fractures on the basis of the following four distinguishing characteristics[24] :

• Extent of comminution
• Radiographic appearance or magnitude of displacement
• Articular joint involvement
• Mechanism of injury

Andersen et al compared the Frykman, Melone, Mayo, and AO/ASIF classification systems and concluded that each of the four systems is characterized by a low degree of intraobserver and interobserver agreement.[25]  Consequently, the use of any of these classifications as the primary method to determine treatment and outcome of treatment is not warranted.

Andersen et al also stated, "Some orthopaedists have expressed concern, especially in training programs, that more effort is spent trying to memorize classification systems for a number of fractures, rather than truly understanding the fracture mechanics or the factors that have significant bearing on prognosis or treatment."[25]

Despite the negative aspects of the various tools for classifying DRFs, the AO/ASIF system reached the "substantial level" for both interobserver and intraobserver agreement when these tools were reduced to the following three broad fracture categories[25] :

• Extra-articular
• Partial articular
• Complete articular

These three general fracture categories are incorporated in the classification system that the authors prefer (see Table 1 below).

Table 1. Classification and Treatment Guidelines for Distal Radius Fractures (Open Table in a new window)

With regard to the radiographic characteristics of intra-articular fractures, the Melone four-part pattern seems to be fairly reproducible. The basic fragments of this pattern consist of the radial styloid, the dorsal lunate facet die-punch fragment, the palmar lunate facet die-punch fragment, and the radial shaft (see the image below). Various combinations of these basic fragments are manifested consistently in intra-articular DRFs. In addition to variability of fragment displacement, variability of comminution of each individual component fragment also exists.

Of historical interest, the Melone four-part pattern can be viewed as the summation of the eponymous Colles, Smith, Barton, and chauffeur fractures.[27]

The volar and dorsal vertical shear fractures (Smith II/volar Barton fracture and dorsal Barton fracture, respectively) have classically been described as partial articular injuries involving the lunate facet of the distal radius. These injuries include volar or dorsal carpal displacement because of the important extrinsic radiocarpal ligaments that attach to the lunate facet. Accordingly, displaced volar and dorsal vertical shear fractures (Barton/Smith fractures) have the same biomechanical implications and treatment methods as displacement of Melone palmar and dorsal lunate facet die-punch fragments, respectively.

The authors' selection of treatment is based consistently on the particular configuration and displacement of the Melone fracture components. Because the goal of a good classification system is to define reproducible clinical characteristics that can guide treatment selection, the authors believe that their treatment algorithm can also serve as a practical classification system for DRFs. (See Table 1 above and Treatment.)

If a dorsal lunate facet die-punch component does not have significant dorsal metaphyseal comminution, it can be reduced against the intact volar surface and stabilized by transfixing percutaneous pins.

Inherent stability is restored with good dorsal cortical apposition. In highly comminuted dorsal fractures in which contact with the dorsal metaphyseal cortex is lost, inherent dorsal stability is established by using bone grafts as void fillers, in combination with external fixation, to maintain neutral tension in the dorsal aspect.

In the presence of unstable volar fragments, the anterior cortex cannot serve as an adequate anterior buttress against which the dorsal fragments can be reduced. In these instances, the authors routinely add a volar plate to stabilize the volar distal cortex (see the image below). Thus, in cases with combined dorsal and volar instability, the dorsal fragments are treated as outlined above, but the volar cortex is reconstructed first with a volar buttress plate.

If a displaced radial styloid component is present, it is reduced manually and, if required, stabilized with two parallel radial styloid pins. Open reduction of the radial styloid may be necessary if closed reduction is not successful, and, in the presence of comminution and instability, volar radial plating of the radial styloid is an effective treatment option. Other treatment modalities, such as the use of small lateral buttress plates and clips are currently being investigated. Pronation or, more commonly, supination deformity of the radial styloid must be corrected. The use of intra-operative fluoroscopy is helpful in identifying rotation of the styloid fragment.

Thus, the classification system the authors prefer is a modification of the AO/ASIF and Melone systems that incorporates the various treatment principles described above. The classification system is derived from rational treatment-based options that the authors believe reflect the physiologic differences in each fracture pattern. Table 1 (see above) represents the authors' classification system and a practical guide for treatment of DRFs.

There are no contraindications for nonsurgical management of a closed distal radius fracture (DRF). Indications for surgical treatment should be based on radiographic findings after initial reduction, expected functional needs, associated medical conditions, and other traumatic injuries (see Surgical Therapy below).

Open fractures necessitate emergency surgical intervention and should be treated according to accepted principles. The decision for initial versus delayed placement of hardware should be based on the level of wound contamination and on the ability to achieve soft-tissue coverage over the implants.

The magnitude and direction of displacement and the type of fragmentation at the fracture site are important factors determining the treatment plan; treatment recommendations are based on these critical parameters as previously presented (see Pathophysiology). Key points can be summarized as follows:

• An intact volar buttress is the key to a stable reduction; when disrupted, this buttress must be restored
• All intra-articular fractures have one or more components of the Melone four-part pattern, and each component must be addressed and stabilized
• Dorsal bone grafting is an important adjunct in promoting stability and healing when dorsal metaphyseal comminution is present
• External fixation should be used in conjunction with dorsal bone grafting when dorsal comminution is present; the external fixator should be used as a neutralization device and can be removed early (~4 weeks) when used in this fashion
• Every patient is unique, and the ultimate treatment plan should be based on individual needs and expectations

Stable fractures

Closed treatment methods are indicated for stable fractures. Stability is predicated on accurate reduction and adequate bony integrity to maintain that reduction. Surgical treatment may be necessary for injuries that are identified as unstable.[12]

Nondisplaced extra-articular and intra-articular fractures

For nondisplaced extra-articular and intra-articular DRFs, immobilization without fracture manipulation is recommended. Experience has demonstrated that a circular cast or even a bivalved cast has the potential for complications, such as compartment syndrome and swelling of the digits. A padded sugar-tong plaster splint with 20-30° of wrist palmar flexion and neutral rotation is a safe alternative, and the elastic bandages around the sugar-tong plaster splint can be adjusted later to accommodate decreased swelling, without manipulation of the fracture.

Three-point molding is an important aspect of the sugar-tong plaster splint because this helps maintain reduction of the fracture. Appropriate molding along the dorsal distal radius, volar distal forearm, and dorsal proximal forearm helps achieve adequate three-point molding. The authors have found that a flat surface of the splint along the volar distal forearm is key to achieving three-point molding (see the images below).

The sugar-tong plaster splint with its U shape around the elbow prevents pronation and supination but allows some elbow motion. Elimination of pronation and supination neutralizes deforming forces (eg, brachioradialis) on the fracture fragments. Wrinkles in the splint must be avoided, especially on the volar side, because such wrinkles can cause local compression of the median nerve, carpal tunnel, and volar skin. Conversion to a short arm circular cast is not always necessary or recommended; however, if it is necessary, it should be done at 2-4 weeks after sugar-tong plaster splint immobilization.

Plain radiographs should always be obtained after splinting to confirm that the fracture fragments are not displaced. Radiographs should be acquired every week for 2-3 weeks after immobilization to ensure stability of the fracture. Maintaining the wrist above the level of the heart and early finger motion facilitate rapid improvement of swelling.

During the period of immobilization, finger motion and "six-pack" finger exercises, as described by Palmer, are important and should be performed at least three times a day (see the image below). These exercises emphasize finger extension, metacarpophalangeal (MCP) joint flexion, proximal interphalangeal (PIP) joint flexion, full finger flexion, finger abduction and adduction, and thumb motion.[28]

After immobilization for a total of 4-6 weeks, the recovery of pronation and supination and wrist flexion and extension should be emphasized. Occupational therapy may be necessary during or after immobilization if the patient has difficulty with finger motion or wrist motion, respectively. Strenuous activities with the affected wrist should be restricted for the first 3 months after injury.

Displaced extra-articular and intra-articular fractures

All displaced DRFs should initially be treated with closed reduction and fracture manipulation and immobilization in a sugar-tong plaster splint. Even if adequate reduction is not achieved, the initial closed reduction limits injury to the nerves, tendons, and soft tissues as a result of the displaced bone fragments. The use of ultrasonography to guide DRF reduction has been shown to be feasible and safe.[29]  

Manipulation of the fracture can be achieved in the emergency department (ED) or outpatient clinic by using a hematoma block and/or sedation or by using a Bier block.[30] Local hematoma block without sedation is believed to be a safe option in the outpatient setting and can be performed as long as 7-10 days after injury.

Longitudinal traction with finger traps is helpful during closed reduction, and if used, the traction should be maintained for several minutes before fracture manipulation to take full advantage of ligamentotaxis and tissue creep. Plain radiographs and, ideally, fluoroscopic images can be used to assess the fracture reduction with traction. If the reduction is inadequate, the fracture can be easily manipulated again.

Articular congruity of the sigmoid notch of the distal radius is just as essential as that of the radiocarpal joint. If the fracture line involves the sigmoid notch, motion arthroplasty of the sigmoid notch can be achieved by pronating and supinating the forearm during the reduction maneuvers. Adequate reduction of the sigmoid notch must also be evaluated on traction and postreduction views.

If adequate reduction is achieved with fracture manipulation, a sugar-tong plaster splint should be applied, with the longitudinal traction in place. As the splint is setting up, the longitudinal traction can be released, and the dorsal and palmar three-point molding of the sugar-tong plaster splint can carefully be completed with light manual traction. The wrist should be placed in 20° volar flexion, neutral rotation, and 15° ulnar deviation to take advantage of ligamentotaxis and three-point molding.

Once the splint is hard, manual traction is released and plain radiographs ordered. Continue the immobilization if the radiographs demonstrate maintained reduction, but operative treatment should be considered if the fracture becomes displaced in the splint. Scheduled follow-up visits with plain radiography are essential in the treatment of DRFs.

If adequate reduction criteria are not achieved, surgical intervention is necessary (see Surgical Therapy). In the interim before surgery, sugar-tong plaster splinting can be used to immobilize the fracture and limit damage to surrounding structures. High-energy injuries are often associated with extensive swelling, and operative intervention should be performed after swelling has decreased, usually several days after injury.[15]

Unlike a nondisplaced DRF, a displaced DRF implies more injury to the soft-tissue envelope; therefore, splint immobilization should be continued for a minimum of 6 weeks or longer.[31, 32] Conversion to a short arm cast can be considered after 4-6 weeks of immobilization. Wrist immobilization, if applied properly, can be maintained for 6-8 weeks without additional adverse effects on the long-term functional outcome.[33] After cessation of immobilization, the same protocol as for nondisplaced fractures must be followed.

In a study of long-term outcomes (mean follow-up, 7.3 years) in children with minimally displaced metaphyseal both-bone forearm fractures who were treated with a below-elbow cast instead of an above-elbow cast, Musters et al found that both primary (loss of forearm rotation) and secondary outcomes (ABILHAND-kids, DASH questionnaire, grip strength, radiologic assessment, and cosmetic appearance) were similar in the two groups.[34] The authors therefore suggested that children with such fractures should be treated with a below-elbow cast.

Surgical treatment is indicated for unstable DRFs. An unstable injury is defined as a fracture that does not reduce adequately with closed fracture manipulation or that loses reduction below acceptable reduction parameters despite appropriate immobilization techniques.[35, 36]

Indications

Graham proposed the following radiographic criteria for acceptable reduction of a DRF[37] :

• Radial shortening less than 5 mm at the distal radioulnar joint (DRUJ) as compared with the contralateral wrist
• Radial inclination of more than 15° on a posteroanterior (PA) image
• Sagittal tilt on the lateral projection between 15° dorsal tilt and 20° volar tilt
• Intra-articular fracture stepoff less than 1-2 mm of the radiocarpal joint

Articular incongruity less than 2 mm of the sigmoid notch of the distal radius is another critical radiographic parameter.

Radial shortening has been shown to be the most important reduction parameter because of its impact on the radiocarpal joint, the DRUJ, and, ultimately, functional outcome.[10, 37, 38, 39, 16, 40, 41, 31, 42, 43, 44, 45]  Palmer and Werner even found that minor axial shortening of 2 mm can alter the contact forces across the entire wrist joint.[42]

Complications of radial shortening include increased pressure on the triangular fibrocartilage complex (TFCC), pain caused by ulnocarpal impingement, increased lunate contact area, an increase of approximately 40% of the ulnar axial load, decreased and/or painful pronation or supination, and decreased grip strength.[38, 42, 46, 47]

Radial inclination less than 15° can cause an appearance of radial deviation of the wrist and changes the load distribution between the scaphoid and the lunate.[42, 48]

Most wrist fractures usually result in a dorsal tilt of the distal radius articular surface in the sagittal plane. Fernandez found that patients with a dorsal tilt more than 25° usually become symptomatic.[41]  Other authors have demonstrated that dorsal angulation is associated with decreased functional results.[39, 16]

Changes in sagittal tilt alter the biomechanics across the wrist joint. Pressure is dispersed over the entire articular surface of the distal radius and ulna at 11° of palmar tilt. As the sagittal tilt increases from 10° palmar tilt to 45° dorsal tilt, the axial load through the ulna increases from 21% to 67% of the total axial force. At 40° of dorsal tilt, most of the axial load is borne by the dorsal aspect of the radioscaphoid and ulnocarpal articulations without any load on the radiolunate joint.[49]

Intra-articular stepoff and gap on the distal radius articular surface have been studied extensively. It generally is agreed that more than 2 mm of articular displacement can lead to radiographic osteoarthritis (OA).[17, 50, 51, 52, 15]  However, radiographic OA does not always indicate poor functional outcome.[39, 41, 17, 53, 54, 33]

Trumble et al noted that intra-articular fractures with more than 1 mm displacement should be treated aggressively because, for example, the wrist articular cartilage is not as thick as that of the knee.[38]  This decreased thickness of cartilage may consequently diminish the ability of the wrist to remodel residual articular incongruity.[55, 15]  Anatomic reduction of the articular surface is recommended to decrease radiographic OA and optimize functional outcome.[47, 17, 51, 53]

In elderly patients, poor radiographic results do not necessarily signify poor functional outcomes.[41, 54]  Satisfactory functional outcomes, regardless of radiographic results, are observed in patients older than 60 years—not because they are older, but because of their lower functional demands. Therefore, nonoperative treatment of DRFs can yield satisfactory outcomes, especially in patients with low functional demands and in patients who are poor operative candidates.[3, 54]

Dorsally displaced extra-articular fractures

Closed reduction with percutaneous pinning is a simple and effective treatment for dorsally displaced extra-articular fractures with large metaphyseal fragments.[56] Cross-pinning with 0.062-in. diameter smooth pins in the radial styloid (two pins) and the dorsal ulnar aspect of the distal radius (one pin) has been shown to be a rigid construct in both torsion and cantilever bending.[57]

The radial styloid is anterior; thus, the radial styloid pins are to be directed in a dorsal proximal ulnar direction.[24] To avoid injury to the extensor tendons, the percutaneous pin should be inserted between the extensor tendons of the first and second, third and fourth, and/or fourth and fifth compartments (see the image below).[58]

Intrafocal (Kapandji) pins are another consideration, especially in the physiologically younger patient, but they should not be used initially in the presence of significant comminution or advanced osteopenia.[45, 59, 58] This technique is especially useful for reducing and holding fractures that redisplace after several weeks of immobilization.

Extensive comminution at the fracture site can occur in physiologically young patients involved in high-energy injuries and in osteoporotic patients with low-energy trauma.[11] When these fractures are reduced, the metaphyseal bone has resultant voids, which require filling with iliac crest bone grafts, allografts, or bone-graft substitutes.

McBirnie et al found a 22% malunion rate in unstable DRFs treated with bone grafting and fixation with a single Kirschner wire (K-wire).[60] This rate suggests that additional support, as with an external fixator or plate, is necessary with this type of treatment. The authors do not use dorsal plates for acute fractures, because some plates can irritate the extensor tendons, and they frequently have to be removed.

Newer low-profile plates and screws are now available. Current external fixators are easy to apply in neutral tension and can be used for fine-tuning difficult reductions. In association with dorsal bone grafts, external fixators maintain neutral tension in the dorsal aspect and can be removed early (~4 weeks) in some fractures.

Bone-void filler provides mechanical support and applies an osteoconductive material to the bone defect.[61, 62, 38, 47] The use of filler ultimately leads to more rapid fracture healing and a decreased incidence of the loss of reduction.

Alluri et al compared the biomechanical stability of Kirschner wire (K-wire) fixation, volar plating, and intramedullary (IM) nailing for unstable extra-articular DRFs with both constant and cyclical axial compression.[63]  More than 300 N of force was required to induce failure of the volar plate and the IM nail, whereas less than 150 M was required for failure of the K-wire construct. The first two constructs showed less than 1 mm of displacement during cyclic loading, whereas the third showed more than 3 mm. Both volar plating and IM nailing demonstrated the necessary biomechanical stability to maintain postoperative reduction in extra-articular DRFs.

Volarly displaced extra-articular fractures

Like its dorsal counterpart, a volar displaced fracture with noncomminuted metaphyseal fragments responds well to closed reduction with percutaneous pinning, which effectively restores the volar buttress in the presence of large volar metaphyseal fragments. The use of dorsal intrafocal pins for stabilization is controversial because these pins may aggravate the volar displacement and fail to restore anatomic alignment. Proper palmar tilt is readily achieved with closed reduction; however, excessive palmar tilt is still possible if volar metaphyseal fragmentation is not properly evaluated on initial radiographs.

With small, comminuted, volar metaphyseal fragments, compression of cancellous bone is expected, with resultant loss of the essential volar buttress. Volar plating stabilizes the fracture, and a bone-void filler may be added. Rigid fixation with a volar plate also permits early range of motion (ROM) out of the plaster splint.

Unlike small-fragment dorsal comminution, small-fragment volar metaphyseal comminution cannot be treated with ligamentotaxis because of the radiocarpal ligamentous anatomy. The volar ligaments are shorter, thicker, and stronger than the longer, thinner, and weaker dorsal ligaments. The stout volar ligaments tighten sooner with longitudinal distraction, resulting in dorsal tilt of the distal fragment.[33, 64, 65, 66]  Because of these strong volar ligaments, which are important for radiocarpal stability, the volar capsule should not be opened.[24] These observations further support the authors' use of a volar plate to reconstruct the volar buttress in the presence of significant volar metaphyseal fragmentation.

Intra-articular fractures

Intra-articular fractures involving dorsal and/or volar metaphyseal fragments are a combination of intra-articular and extra-articular displaced injuries. As such, their treatment plans are additive. Ideally, all intra-articular fragments should be anatomically reduced to retard the development of OA. Closed reduction and splint immobilization techniques are similar to those used for extra-articular fractures.

Dorsally displaced lunate facet die-punch fractures

Dorsally displaced lunate facet die-punch fractures should be anatomically reduced (with either an open or closed technique) to realign the radiolunate joint and the sigmoid notch and to restore the integrity of the medial complex. The dorsal ulnar fragment can be treated with closed reduction and stabilized with a single pin. However, a limited dorsal open reduction between the fourth and fifth extensor compartments may be necessary.[47]

If the dorsal metaphyseal fragments are small (comminuted), dorsal bone grafts (or substitutes) and external fixation are recommended, as described for extra-articular comminuted fractures. In either case, the intact volar cortex serves as a buttress against which stability of the dorsal fragment is maintained.

Volarly displaced lunate facet die-punch fractures

The volar fragment of the coronal split has a tendency to rotate dorsally when tension is applied to the volar capsule, and such displacement necessitates a volar open reduction. If this occurs, the volar medial fragment is buttressed with a small plate (see the image below). Volar plating does not have the same complications as dorsal plating and does not necessitate routine early hardware removal.

Dorsal and volar metaphyseal fragments

When displacement (instability) of dorsal and volar metaphyseal fragments is present, dual approaches are necessary. As always, a stable volar buttress is critical for providing a fulcrum against which the dorsal fragments are reduced. Volar plating provides this stability and prevents excessive volar displacement secondary to manipulation of dorsal fragments and/or placement of bone grafts.[60] When dual incisions are necessary, an attempt should be made to close the volar incision before the dorsal incision is made to minimize tissue swelling and to limit skin tension with wound closure.[15]

Radial styloid fractures

The isolated radial styloid fracture (ie, chauffeur's fracture) is uncommon. When present, this fracture should be critically evaluated for associated injuries, such as a scaphoid facet die-punch fracture and, more important, a carpal ligament injury.[15]

This fracture responds well to closed reduction and can successfully be pinned percutaneously.[47] However, if small metaphyseal fragments are present or if closed reduction is not successful, open reduction with internal fixation (ORIF), through either a direct dorsal approach or a standard volar (Henry) approach, must be considered. The latter is chosen when the styloid fragment is displaced volarly or when it has a large volar extension.

Most often, the styloid fragment is part of a four-part displacement pattern, as Melone described.[10] In this instance, the treatment of all components is additive. The reduction and stabilization of the radial styloid, dorsal lunate facet die-punch, and volar lunate facet die-punch fractures are assessed and treated as described above, either individually or in combination.

Central depression fractures

Central depression of lunate or scaphoid facets should be evaluated with computed tomography (CT) or plain tomography to fully assess the magnitude of articular stepoff. Impacted fractures more than 1-2 mm should be treated with reduction via a limited dorsal approach, with bone grafting for mechanical support, and with percutaneous pinning for stability.[47, 67] The reduction can be confirmed by means of fluoroscopy or, more precisely, via direct visualization (capsulotomy) or arthroscopy. Arthroscopically assisted reductions have the advantage of minimizing capsular scarring; however, arthroscopy has not yet been proved to improve outcomes.[15]

Early complications

DRFs can directly or indirectly cause contusion, laceration, and/or entrapment of skin, tendons, nerves, fascia, muscle compartments, and vessels by bone fragments.[68, 69, 70] The potential for early soft-tissue complications increases with any delay in initial treatment; therefore, early initial reduction of the fracture can minimize the effects of these associated injuries.

Iatrogenic injury must also be avoided, regardless of whether treatment is conservative or surgical. Cast treatment can lead to skin pressure necrosis and median nerve compression.[68] Joint contractures are associated with the Cotton-Loder position (ie, excess palmar flexion with ulnar deviation).[10] Circumferential casts or dressings cannot allow for expected swelling, and compartment syndrome can subsequently occur.[68] Persistent finger edema can also result in stiffness of the digits. Casts that block finger motion are unnecessary and potentially harmful.

Surgical management of DRFs can also result in complications. Percutaneous placement of pins is technically simple but can easily injure extensor tendons and nerves.[71] Excessive traction by external fixation can lead to joint stiffness and injury of carpal ligaments.[65]  Rare cases of combined median and ulnar nerve palsy after ORIF have been reported.[72] Careful handling of soft tissues in all surgical approaches is essential to prevent postoperative skin damage and infection.

Caution should be used when bone grafts are used in intra-articular fractures to avoid intra-articular extravasation. Rupture of the extensor pollicis longus (EPL) can occur with surgical or nonsurgical treatment. Careful reduction of dorsal fragments helps to avoid this complication. In dorsal approaches to the wrist, releasing the EPL tendon from its compartment can also help to avoid tendon constriction and injury.

Early reflex sympathetic dystrophy (RSD) should always be suspected in the presence of inappropriate postoperative pain, swelling, and stiffness. RSD may be caused by tight dressings, unresolved nerve injury (eg, carpal tunnel syndrome), or inherent patient susceptibility to this complication. In any event, early recognition and treatment are effective in most cases. Removal of the instigating factors, active ROM of thumb and fingers, sensory stimulation, activities of daily living (ADLs) of the hand, and psychotropic medication all have beneficial effects.

Long-term complications

The list of long-term complications associated with DRFs is extensive and not within the scope of this article. This section provides a general overview of the common problems. Pain and extremity function should guide the treatment plan; radiographic findings guide the surgical approach.

Extra-articular malunion is often multidirectional and can result in malalignment of the DRUJ and the carpal bones. Typically, extra-articular malunions are shortened and tilted dorsally and treated with distal radial osteotomy, corticocancellous bone grafting, and dorsal-plate fixation. On correction of the distal radius alignment, the radial length and reduction of the DRUJ must be critically assessed.

Further considerations include ulnar shortening, distal ulnar ablation (Darrach), partial distal ulnar resection with or without interposition arthroplasty, or distal radioulnar fusion with ulnar pseudarthrosis (Sauve-Kapandji). Many of these DRUJ procedures can be performed without correction of the distal radius malunion.[37, 40, 41, 73]

Although many patients report excellent results after reconstruction of distal radius malunions (particularly DRUJ malalignment), data from good long-term outcome studies are lacking. An intra-articular stepoff more than 2 mm can lead to degenerative arthritis, but these radiographic findings have not been correlated with long-term patient outcomes.

Following treatment of DRFs, functional impairment is possible for as long as 2 years. For this reason, the authors continue aggressive therapy, including active and active-assisted ROM, progressive-resistance exercises, and work rehabilitation for as long as improvement is noted objectively. Only then is it appropriate to assess the need for reconstructive surgery.