Arthroscopic Diagnosis of Carpal Ligament Injuries with Distal Radius Fractures

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CHAPTER 45 Arthroscopic Diagnosis of Carpal Ligament Injuries with Distal Radius Fractures

Carpal ligament injuries have been found in association with distal radius fractures (Fig. 45-1)¹^–³ and with scaphoid and other fractures (Fig. 45-2).^4,⁵ In contrast to these injuries, which sometimes are radiographically visible, there are other associated soft tissue injuries involving the median nerve, the radial artery (Fig. 45-3), or flexor tendons with ruptures. In addition, numerous articles have highlighted the extent of associated cartilage and ligament injuries with displaced distal radius fractures, especially in nonosteoporotic individuals.⁶^–¹⁰ These injuries occasionally can be found with fluoroscopy or magnetic resonance imaging,¹¹ but are most often found when the distal radius fracture is managed with wrist arthroscopy as an adjunct.

FIGURE 45-1 A and B, Scapholunate dissociation found before and after treatment of displaced distal radius fracture.

FIGURE 45-2 Scapholunate dissociation found in association with a distal ulnar fracture.

FIGURE 45-3 A to D, Dorsally dislocated distal radius fracture, which after manipulation still had an unacceptable displacement. E, At open reduction with a palmar approach, the radial artery was injured and interposed in the fracture.

There has been a tendency to overlook these injuries, in contrast to the awareness of similarly important injuries in the lower extremity (Fig. 45-4). To minimize the impact of missed associated injuries, we have to improve our knowledge about them and improve our management of distal radius fractures. We should try to define, classify, and treat the devastating “syndesmosis” injuries of the wrist as soon as possible (Fig. 45-5).

FIGURE 45-4 Syndesmosis injury in an ankle without fracture. This devastating ligament injury is defined and classified and receives full treatment and attention in the orthopaedic community.

FIGURE 45-5 “Syndesmosis” injury of the wrist with an undetected, untreated ulnoradial ligament (peripheral triangular fibrocartilage complex) tear where the signs of the healed distal radius fracture can be seen.

Assessment and Decision Making for Associated Injuries

Injuries associated with distal radius fractures should be looked for at least at the following opportunities when the fracture is reviewed and management is discussed:

1. At the time of the fracture when the initial radiographs are reviewed

2. At the fracture clinic during the first week

3. At the fracture clinic at the 10- to 14-day follow-up

4. At the time of surgical treatment

5. At a later follow-up about 3 months after the fracture

At the Time of the Fracture When Initial Radiographs Are Reviewed

There is an obvious difference between patients and their needs, which can be clearly seen already at the initial presentation, where a range of associated, but preexisting conditions can be found (Fig. 45-6). Sometimes the associated injuries are obvious, but in most situations the soft tissue injuries are not evident at all (Fig. 45-7). We then either have to find them or have to exclude that such associated injuries exist.

FIGURE 45-6 A and B, Preexisting rheumatoid arthritis (A) and osteoarthritis (B) at the initial presentation of a distal radius fracture. Knowledge of preexisting problems helps the orthopaedist understand how to manage the acute fracture.

FIGURE 45-7 A, Trans-styloid perilunate dislocation with all the signs of the Mayfield chain of intercarpal ligament injuries. B and C, Distal radial fracture at the initial presentation (B) and with stress views reflecting an ulnoradial ligament injury (C).

At the Initial Presentation, at the Fracture Clinic during the First Week, and at the 10- to 14-Day Follow-up

The radiographs should always be reviewed with the utmost scrutiny regarding degree of displacement, including the ulnar styloid fracture, which may indicate an ulnoradial ligament detachment (peripheral triangular fibrocartilage complex [TFCC] injury) (Fig. 45-8). The three carpal arcs of Gilula¹² (Fig. 45-9), which are indicative of intercarpal ligament injury, always should be checked.

FIGURE 45-8 A, Ulnar styloid fracture at the base, which may represent a destabilizing ulnoradial ligament tear causing instability of the distal radioulnar joint. B, The ulnar styloid is avulsed in a radial direction as a sign of involvement of the ulnoradial ligament being attached to the avulsed ligaments like two reins.

FIGURE 45-9 The three carpal lines of Gilula (arrows), which, if disrupted, reveal an intercarpal ligament injury.

The most important prognostic factor for a bad outcome after distal fractures is the ulnar-positive variance ¹³; there is a 2.5 times increased risk for a bad outcome in nonosteoporotic individuals if the ulnar-positive variance is more than 2 mm. An ulnar-positive variance more than 2 mm also has been shown to give a 3.9 relative risk (95% confidence interval 1.1 to 13.3; P = .01) of a grade 3 to 4 scapholunate (SL) ligament injury (Lindau classification system).^7,¹⁴

The second most important prognostic factor is articular involvement; an intra-articular incongruency of more than 1 mm leads to osteoarthritis).¹⁵ An intra-articular fracture also has been shown to be a potentially important factor for a poor outcome in nonosteoporotic patients.¹³ Fractures that have a partial intra-articular (AO type B) or combined extra-articular and intra-articular involvement (AO type C) have been shown to increase the risk for a Lindau grade 3 to 4 SL ligament injury^7,¹⁴ at the time of injury and to increase the risk for radiographic dynamic or static SL dissociation 1 year after the trauma.¹⁴

Patient age, metaphyseal comminution of the fracture, and ulnar variance have been shown to be the most consistent predictors of radiographic outcome.^13,¹⁶ Dorsal angulation and radial length have not been shown to be associated with a bad outcome,^13,¹⁶ which may explain why the AO and Frykman classifications¹⁷ have failed to correlate with the outcome.¹⁸

An evidence-based algorithm can be very helpful in managing distal radius fractures (Fig. 45-10), where the search for associated injuries is added to the general decisions regarding management of the fracture. There is a special emphasis in the algorithm on the differences between nonosteoporotic and osteoporotic patients.¹⁹ The differences are in regard to fracture pattern, associated injuries, treatment alternatives, and outcome, which reflect the future need of patients for their wrists after the injury. Initial assessment also should address the potential risks not obvious on an x-ray, where palmarly displaced fragments especially can cause radial artery injuries, flexor tendon ruptures, or median nerve entrapments (carpal tunnel syndrome).