Introduction

Displaced intra–articular fractures of the distal radius are a unique subset of radius fractures. These fractures are usually the result of a high–energy injury and are usually associated with intra–articular soft–tissue injuries. These fractures are traditionally unstable, and are less amenable to closed manipulation and casting.

Lafontaine has described several radiographic features that signify when a fracture of the distal radius is unstable.¹ These include initial dorsal angulation greater than 20 degrees, extensive dorsal comminution, associated ulnar styloid fracture, significant intra–articular involvement, and older patients greater than the age of 60.

The prognosis for intra–articular fractures of the distal radius has been shown to depend on numerous factors.² These include the amount of radial shortening, residual extra–articular angulation, articular congruity of both the radiocarpal and radioulnar joints, and associated intra–articular soft–tissue injuries. Trumble et al., in their review of 52 intra–articular fractures, noted that factors that strongly correlated with a successful outcome included the amount of residual radial shortening and intra–articular congruity.³

The use of wrist arthroscopy as an adjunct in the management of displaced intra–articular distal radius fractures takes advantage of its ability to view the articular surface with bright light and magnified conditions with minimal surgical morbidity.⁴ Fracture hematoma and debris may be arthroscopically lavaged, which potentially can improve the patient’s final range of motion⁵ (Figure 17.1). In addition, associated intra–articular soft–tissue injuries may be detected and managed at the same sitting⁶ (Figure 17.2). Pathology not readily identified on plain radiographs is frequently discovered during arthroscopic–assisted reduction and internal fixation of distal radius fractures. In most instances, it is much easier to manage an acute soft–tissue injury that occurs with a distal radius fracture than chronic pathology. The purpose of this chapter is to review the rationale and technique in the application of wrist arthroscopy as a useful adjunct in the management of displaced intra–articular fractures of the distal radius.

FIGURE 17.1 Loose bodies are frequently seen during arthroscopic-assisted reduction of distal radius fractures, which are not readily apparent on plain radiographs. Removal of these loose fragments and cartilage debris may improve the patient’s final prognosis.

FIGURE 17.2 Partial and complete tears to the interosseous ligaments are frequently identified during the wrist arthroscopic procedure. Management of acute tears to the interosseous ligaments may have a better prognosis compared to chronic injuries.

Two millimeters of articular displacement has over the past several years become a well–established critical threshold for articular incongruity of the distal radius. Knirk and Jupiter, in their classic article, demonstrated the importance of an articular reduction within 2 mm or less.⁷ A patient whose articular reduction is greater than 2 mm at final follow–up visit has a significantly higher incidence of degenerative changes within the wrist. Bradway and Amadio further substantiated these findings in their study.⁸

In their series of 40 patients, Fernandez and Geissler noted that the critical threshold may be as low as 1 mm or less.⁹ They reported in their study that the incidence of complications was substantially lower and articular reduction was within 1 mm or less.

Edwards et al. described the advantage of viewing intra–articular reduction by wrist arthroscopy compared to monitoring under fluoroscopy alone.¹⁰ In their series, 15 patients underwent arthroscopic evaluation of the articular surface of the distal radius following reduction and stabilization under fluoroscopy. They found that 33% of the patients had an articular step–off of 1 mm or more as viewed arthroscopically. Frequently, the fragment was rotated. Wrist arthroscopy is particularly useful in judging the rotation of fracture fragments, which is not readily identifiable under fluoroscopy. Edwards et al. concluded that utilizing wrist arthroscopy as an adjunct may detect residual gapping not previously identified under fluoroscopy alone.

A high incidence of associated intra–articular soft–tissue injuries involving the triangular fibrocartilage complex and the interosseous ligaments has been shown by several studies of displaced intra–articular fractures of the distal radius.¹¹ Mohanti and Fontes, in two separate wrist arthrogram studies, noted a high incidence of tears of the triangular fibrocartilage complex associated with distal radius fractures. Fontes, in his series, noted a 66% incidence of tears of the triangular fibrocartilage complex in 58 patients.¹² Similarly, Mohanti noted an injury of the triangular fibrocartilage complex in 45% of 60 patients in his series.¹³

Several recent arthroscopic studies have documented incidences of associated intercarpal soft–tissue injuries with fractures of the distal radius. In three recent published studies, an injury to the triangular fibrocartilage complex seems to be the most common associated intra–articular soft–tissue injury. Geissler et al. reported their experience in 60 patients with displaced intra–articular fractures of the distal radius undergoing arthroscopic–assisted reduction and evaluation.¹⁴ The criterion for surgical stabilization in his series was an intra–articular fracture displaced 2 mm or more that cannot be reduced by closed manipulation. In Geissler et al.’s series, 49% of the patients had a tear of the triangular fibrocartilage complex. An injury to the interosseous ligaments was less common. Tears to the scapholunate interosseous ligament were present in 32% of patients, and injury to the lunotriquetral interosseous ligament was identified in 15%.

Lindau, in a similar arthroscopic study of 50 patients, noted that tears of the triangular fibrocartilage complex were present in 78% of patients, injuries to the scapholunate ligament were identified in 54% of patients, and tears of the lunotriquetral interosseous ligament were less common and seen in 16% of patients.¹⁵ Hanker, in a series of 65 patients, noted that tears of the triangular fibrocartilage complex were very common and were present in 55% of the patients in his series.¹⁶ Although it is clearly documented that associated soft–tissue injuries are common with displaced intra–articular fractures of the distal radius, how they may affect the final outcome in patients is still unknown.

Geissler et al. described an arthroscopic classification of an interosseous ligament injury based on their work on arthroscopic management of fractures of the distal radius.¹⁴ They noted that a spectrum of injury may occur to the interosseous ligament. The ligament attenuates, and then eventually tears, and the degree of rotation between the carpal bones increases. The scapholunate interosseous ligament appears to tear from volar to dorsal. This arthroscopic classification of carpal instability is based on observation of interosseous ligaments from both the radiocarpal and midcarpal spaces (Table 17.1).

Table 17.1 Geissler Arthroscopic Classification of Carpal Instability

The normal scapholunate and lunotriquetral interosseous ligaments have a concave appearance between the carpal bones as viewed from the radiocarpal space. The scapholunate ligament is best seen with the arthroscope in the 3–4 portal. The lunotriquetral interosseous ligament is best observed with the arthroscope placed in either the 4–5 or 6–R portal. The lunotriquetral interval will not be adequately seen with the scope in the 3–4 portal alone. In the midcarpal space, the scapholunate interval should be tight and congruent without any articular step–off. Similarly, the lunotriquetral interval should be congruent, but usually a 1–mm step–off or slightly increased play may be seen between the lunate and triquetrum as observed from the radial midcarpal space. A probe or needle may be inserted in the ulnar midcarpal space to evaluate the amount of play between the carpal bones.

In Geissler grade I injuries, there is a loss of the normal concave appearance between the carpal bones as the interosseous ligament attenuates and becomes convex (as seen in the radiocarpal space). Hemorrhage may be seen within the ligament itself in acute situations. However, in the midcarpal space the interval between the carpal bones will still be tight and congruent (with no step–off).

In Geissler grade II injuries, the interosseous ligament continues to become attenuated and becomes convex (as seen in the radiocarpal space, similar to grade I injuries). There is no gap between the carpal bones. However, in the midcarpal space the interval between the involved carpal bones is no longer congruent and a step–off is present. With scapholunate instability, there is slight palmar flexion of the dorsal edge of the scaphoid compared to the lunate. In lunotriquetral instability, the interosseous ligament again becomes attenuated as seen from the radiocarpal space with the arthroscope in the 6–R portal. In the radial midcarpal space, increased play will be seen between the lunate and triquetrum as palpated with a probe.

In Geissler grade III injuries, the interosseous ligament now starts to tear from volar to dorsal as seen with the arthroscope in the radial midcarpal space. A probe is frequently helpful to demonstrate the gap between the involved carpal bones. In the midcarpal space, a 2–mm probe may be placed between the carpal bones and twisted. The dorsal portion of the interosseous ligament is still intact, and complete separation of the carpal bones is not seen.

In Geissler grade IV injuries, the interosseous ligament is completely detached and the arthroscope may be passed freely from the radiocarpal space through the tear to the midcarpal space. This is the so–called “drive–through sign.”

It is felt that Geissler grade I injuries are consistent with a wrist sprain and usually respond to immobilization over a period of weeks. In Geissler grade II and grade III tears, these may be arthroscopically reduced and pinned in the acute situation. Pinning is not recommended for chronic injuries of the interosseous ligaments. In Geissler grade IV injuries, where there is complete detachment of the interosseous ligament, it is felt that open repair will have the best prognosis in an acute situation.

Large–joint instrumentation is not appropriate for arthroscopically assisted reduction of distal radius fractures. Smaller–joint arthroscopic instrumentation is essential. The small–joint arthroscope is approximately 2.7 mm, and even smaller scopes may be utilized if desired. When the arthroscope is initially placed in the wrist, it is usually full of fracture debris and hematoma. It is useful to irrigate out the fracture debris and utilize the shaver (3.5 mm or less) to clear the remaining hematoma to improve visualization, particularly to judge the rotation of the fracture fragments.

A traction tower is very useful in the arthroscopic–assisted management of intra–articular fractures of the distal radius. A traction tower allows the surgeon to flex, extend, and radial and ulnar deviate the wrist to help reduce the fracture fragments while maintaining constant traction to allow visualization. A new traction tower was designed to allow the surgeon to simultaneously evaluate arthroscopically the articular reduction and to monitor the reduction under fluoroscopy (Figure 17.3). The traction bar is uniquely placed at the side of the wrist rather than at its center, so that it does not block fluoroscopic evaluation and the surgeon does not need to work around a central bar. In addition, by having the traction bar at the side rather than centrally allows the surgeon to simultaneously arthroscope the wrist and stabilize the fracture while obtaining access through a standard volar approach.

FIGURE 17.3 A new traction tower was developed to allow for simultaneous arthroscopic reduction of the distal radius fracture and fluoroscopic examination. This greatly simplifies the procedure.

The surgeon can fluoroscopically evaluate the position of the plate and screw insertion during stabilization. This new traction tower allows a surgeon to perform arthroscopic–assisted fixation in both the vertical and/or horizontal planes, depending on the surgeon’s preference.(Figure 17.4). If a traction tower is not available, the wrist may be suspended with finger traps attached to a weight over the end of a hand table in the horizontal position, or with a shoulder holder in the vertical position. A small bump is useful to place under the wrist if weights are being utilized over the end of the table to maintain the wrist in slight flexion.

FIGURE 17.4 The new tower may be placed in a vertical or horizontal position for arthroscopic-assisted reduction of distal radius fractures, depending on the surgeon’s preference.

Thorough irrigation of the joint is necessary to wash out the fracture hematoma to improve visualization. Inflow is usually provided through a 14–gauge needle through the 6–U portal. In addition, it is important to provide outflow to limit fluid extravasation into the soft tissues. Outflow is provided through the arthroscope cannula. An intervenous extension tubing is connected to the arthroscope cannula, which drains then into a basin to limit fluid extravasation and not onto the surgeon’s lap or floor. It is felt that a separate inflow and outflow is necessary to improve irrigation of the joint rather than inflow through arthroscope cannula alone. The small–joint cannula in wrist arthroscopy does not allow much space between the cannula and the arthroscope itself, and this limits the amount of fluid irrigation through the arthroscope cannula. For this reason, it is felt that it is best to have a separate inflow through the 6–U portal.

A fracture of the distal radius wrist is frequently swollen. Because of this reason, it is fairly difficult to palpate the traditional extensor tendon landmarks for wrist arthroscopy. However, the bony landmarks can usually still be palpated and marked. These bony landmarks include the bases of the metacarpals, the dorsal lip of the radius, and the ulnar head. The traditional viewing portal is the 3–4 portal, which is made between the third and fourth dorsal extensor compartments. The 3–4 portal is made in line with the radial border of the long finger.