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Fracture-Dislocations You Can't Afford to Miss

Edward Thompson, MD; Michael Cordas, Jr, DO

THE PHYSICIAN AND SPORTSMEDICINE - VOL 24 - NO. 6 - June 96


In Brief: Occult dislocations can accompany extremity fractures and may lead to serious complications if undetected and untreated. Physicians, therefore, need to watch for uncommon trauma like distal radius fractures with radioulnar joint disruption (Galeazzi fractures), proximal ulna fractures with radial head dislocation (Monteggia fractures), and midfoot dislocations with or without fracture (Lisfranc injuries). Injury recognition involves comparing important historical features like a fall onto an outstretched hand, physical exam findings such as the nature of the pain, and sometimes-subtle radiographic clues. Treatment is usually surgical.

Most traumatic orthopedic injuries involve common sprains, strains, or fractures that are rapidly treated. However, the unsuspecting physician occasionally may be blindsided by an unusual trauma case that, if misdiagnosed, could result in serious disability.

Among such potential disasters are fractures associated with occult dislocations. Galeazzi and Monteggia fractures (involving the forearm) and Lisfranc injury (involving the foot), despite their unwieldy eponyms, are important examples of complicated trauma that may initially seem straightforward.

Though it is important to look for a fracture in trauma cases, it is equally important to diagnose any dislocation. Physicians, therefore, must maintain a meticulous and thoughtful approach to extremity trauma. A few basic principles in approaching any potential fracture may be helpful to remember:

  • An accurate history is essential; the mechanism of injury is critical.
  • The joints above and below the site of injury must be examined carefully, and, when appropriate, radiographed.
  • Neurovascular status of the limb must be assessed, and associated injuries, including dislocations, must be considered.

Radius Fracture With Radioulnar Disruption

First described by Sir Astley Cooper in 1822 and named after Riccardo Galeazzi (who reported a series of patients in 1934) (1), a distal radius fracture with traumatic dislocation or subluxation of the distal radioulnar joint (figure 1: not shown) typically occurs during a fall onto an outstretched hand with the forearm in pronation. It also may infrequently result from a direct blow to the dorsolateral wrist (2), such as might occur in collision sports.

The fracture is usually diagnosed during the initial visit, but the dislocation—which may appear clearly only after treatment—can be missed and result in disability (3). On presentation, the patient will obviously splint the involved area; pronation and supination will be markedly painful. If the dislocation is severe enough, the ulnar styloid process may be quite prominent; however, the injury may clinically appear to be a simple fracture. Though the wrist is typically tender, distal neurovascular injury is rare. When nerve injury does occur, it most commonly involves the radial nerve.

X-rays will show the radius fracture, usually not comminuted, with the radius appearing shortened (usually by more than 5 mm relative to the distal ulna) by the pull of the pronator quadratus on the fracture site. Radial shortening highlights a gap in the normal space between the radius and the ulna on anteroposterior view. An associated fracture of the styloid base may appear as well. A lateral wrist x-ray may show dorsal angulation of the radius relative to the ulna (figure 1c: not shown).

The traditional treatment of choice in this type of forearm fracture is immediate plate fixation (4). Often, the plate remains in place until the athlete completes his or her career.

If this injury is mistakenly casted as a simple radius fracture, subluxation of the distal radioulnar joint and dorsal angulation of the radial fracture can occur. If not treated definitively within 10 weeks, the dislocation may lead to chronic disability, particularly decreased forearm supination and pronation, pain, and weakness (3,5).

Ulna Fracture With Radial Head Dislocation

Giovanni Battista Monteggia 180 years ago first described a fracture involving the proximal third of the ulna and dislocation of the radial head (figure 2: not shown). Uncommon posterior dislocations of the radial head with Monteggia fracture are usually seen in adults, while the more common anterior dislocations are found predominantly in children (2).

The mechanism of injury is debated, but most authorities believe that a fall on an outstretched and hyperpronated hand produces anterior radial head dislocation. Children may land directly on an arm that is reflexively breaking a fall, whereas an adult's injury may stem from a more significant fall or a direct blow that is often part of multiple trauma (6).

Monteggia fracture is easily missed: Speed and Boyd (7), in a 1940 series, showed that more than 50% of these lesions were not recognized until more than 4 weeks after the injury. Although that percentage is thought to be lower now, this fracture is sometimes still unrecognized by treating physicians and radiologists.

On presentation, the patient may not have impressive pain at rest, but elbow flexion and forearm supination will be restricted (8). The patient typically has a painful elbow during range-of-motion assessment and resists flexion, extension, and rotation.

If the elbow is included in the radiographs ordered, the ulna fracture (with or without a radius fracture) is usually visible. The evaluating physician should ensure that the radial head aligns with the humeral capitellum in a "ball-in-cup" manner regardless of the x-ray view. A simple way to evaluate normal alignment is to see if a line drawn through the radius' long axis contacts the capitellum in any position of elbow flexion or extension (figure 2: not shown).

Comparison radiographs of the unaffected extremity may not be uniformly useful (9), but if the diagnosis is uncertain, comparison views may help to delineate subtle elbow pathology. (In one emergency department, elbow fractures were the most commonly missed fracture diagnosis (10). Also, the elbow is the second most frequent site of dislocation, after the shoulder (11).)

Ulna fractures involving dislocation of the radial head may be treated by closed reduction in children, with a posterior long arm splint. Monteggia fracture is usually considered a more severe injury in adults (6), who usually require open reduction and internal fixation regardless of the time postinjury (12).

It is not unusual for adults and children to have a transient paralysis of the deep branch of the radial nerve (the posterior interosseous nerve). This paralysis usually resolves without treatment if the fracture is recognized early and is not accompanied by a radius fracture (13).

If this injury is treated as a simple fracture, chronic irreducible radial head dislocation may occur if the annular ligament is ruptured. Because of the accompanying dislocation, a chronic malunion or nonunion may also result if simple closed reduction of the fracture is attempted.

Tarsometatarsal Joint Disruption

Jacques Lisfranc, a surgeon in Napoleon's army, was widely known for his ability to amputate a foot in less than a minute. Fortunately for this discussion, he also eloquently described the articulations in the foot. The foot can be functionally and conceptually divided into three components: the forefoot (metatarsals and phalanges); the midfoot (navicular, cuneiforms, and cuboid); and the hindfoot (talus and calcaneus). The multiple articulations between the forefoot and midfoot are collectively referred to as the Lisfranc joint (14).

A Lisfranc injury involves disruption between the forefoot and the midfoot, with or without associated fractures. Any associated fractures tend to be in the midfoot. The first metatarsal is typically dislocated either medially or laterally from the first cuneiform, while the other four metatarsals are displaced laterally, usually in combination with a fracture at the base of the second metatarsal. Although a fracture is not always obvious (figures 3a and 3b: not shown), a fracture of the base of the second metatarsal suggests pathology in the tarsometatarsal articulations (figure 3c: not shown).

Injury can stem from either direct or indirect trauma. A severe twisting injury, such as in a directional change in football or basketball, can exert enough stress to disrupt the Lisfranc joint. Also, severe bending forces involving the ball of the foot can injure the tarsometatarsal joints. For example, when a motocross rider's foot is caught between the foot pedal and the ground with the toes in dorsiflexion, a Lisfranc injury can result.

Since blood supply to the forefoot can be compromised by the dislocation and subsequent swelling, compartment syndrome may develop and result in serious disability. Circumferential casts applied to the fracture without attention to the dislocation may also result in compartment syndrome if the patient is not monitored closely.

The patient's initial presentation, if made shortly after the injury, may be rather unremarkable until massive swelling sets in. Vascular compromise might not occur until late in the clinical presentation.

History of a significant foot injury and pain, paresthesias, or swelling markedly out of proportion to radiographic findings should raise suspicion of a possible forefoot dislocation. Comparative views of the normal foot may be the only way to detect the subtle widening of the space between the shafts of the first and second metatarsals or to see the proximal shift of the fifth metatarsal base. In a normal foot, the medial aspect of the middle cuneiform is in line with the medial aspect of the second metatarsal.

Subtle injuries can cause initial x-rays to be falsely reassuring because of spontaneous reduction of the dislocation (14). Weight-bearing (figures 3b and 3c: not shown) or stress radiographs or fluoroscopy can be helpful in this situation. Prompt orthopedic referral is necessary for all Lisfranc injuries.

Suspected disruption of the articulations between the midfoot and forefoot warrants placement in a noncircumferential bulky splint and immediate referral to an orthopedic surgeon for urgent care. Treatment might involve open reduction and internal fixation if closed reduction is unsuccessful (15). Traumatic painful arthritis, however, may develop regardless of the method of reduction, so arthrodesis may ultimately be required to give the patient symptomatic relief.

Detecting Complicated Fractures

Complicated fractures with concomitant dislocations can be difficult to diagnose and can result in serious consequences if not recognized early. Remembering the corresponding eponyms is not important. What is critical is to methodically approach any patient who has wrist, elbow, or foot pain so that these unusual injuries are recognized and treated appropriately.

References

  1. Bruckner JD, Lichtman DM, Alexander AH: Complex dislocations of the distal radioulnar joint: recognition and management. Clin Orthop 1992; Feb(275):90-103
  2. Simon RR, Koenigsknecht SJ, Stevens C: Emergency Orthopedics: The Extremities, ed 2. Norwalk, CT, Appleton & Lange, 1987
  3. Schneiderman G, Meldrum RD, Bloebaum RD, et al: The interosseous membrane of the forearm: structure and its role in Galeazzi fractures. J Trauma 1993; 35(6):879-885
  4. Campbell RM Jr: Operative treatment of fractures and dislocations of the hand and wrist region in children. Orthop Clin North Am 1990;21(2):217-243
  5. Bhan S, Rath S: Management of the Galeazzi fracture. Int Orthop 1991;15(3):193-196
  6. Ovesen O, Brok KE, Arreskov J, et al: Monteggia lesions in children and adults: an analysis of etiology and long-term results of treatment. Orthopedics 1990;13(5):529-534
  7. Speed JS, Boyd HB: Treatment of fractures of ulna with dislocation of head of radius. JAMA 1940;115 (20):1699-1704
  8. Stoll TM, Willis RB, Paterson DC: Treatment of the missed Monteggia fracture in the child. J Bone Joint Surg (Br) 1992;74(3):436-440
  9. Chacon D, Kissoon N, Brown T, et al: Use of comparison radiographs in the diagnosis of traumatic injuries of the elbow. Ann Emerg Med 1992;21(8):895-899
  10. Freed HA, Shields NN: Most frequently overlooked radiographically apparent fractures in a teaching hospital emergency department. Ann Emerg Med 1984;13(10):900-904
  11. Linscheid RL, Wheeler DK: Elbow dislocations. JAMA 1965;194(11):1171-1176
  12. Dormans JP, Rang M: The problem of Monteggia fracture-dislocations in children. Orthop Clin North Am 1990;21(2):251-256
  13. Gibson WK, Timperlake RW: Operative treatment of a type IV Monteggia fracture-dislocation in a child. J Bone Joint Surg (Br) 1992;74(5):780-781
  14. Schneider FR: Orthopaedics in Emergency Care. St Louis, Mosby, 1980
  15. DePalma AF, Connolly JF: DePalma's The Management of Fractures and Dislocations: An Atlas, ed 3. Philadelphia, WB Saunders Co, 1981

We thank Paul Freudigman, MD, for his assistance in preparing the radiographs.

Dr Thompson is the medical director of family practice residency at the Harrisburg Hospital in Harrisburg, Pennsylvania. Dr Cordas is the coordinator of primary care sports medicine and a team physician at Pennsylvania State University in State College, Pennsylvania. Address correspondence to Edward Thompson, MD, 122 S Filbert St, Mechanicsburg, PA 17055.


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