Session VIII - Upper Extremity

Fracture-Dislocation of the Elbow: The Risk of Recurrent Instability According to Injury Pattern

David Ring, MD; Jesse B. Jupiter, MD; Jeffrey Zilberfarb, MD; Massachusetts General Hospital,Beth Israel-Deaconess Medical Center, Boston, MA

Introduction: Interpretation of the published data regarding fracture-dislocations of the elbow is hindered by frequent failure to characterize the pattern of each injury. We undertook a retrospective review of six years, experience at two Level 1 trauma centers in the treatment of fracture-dislocations of the elbow with the hypothesis that these injuries occur in a limited number of distinct injury patterns, each of which is associated with specific pitfalls that can contribute to the occurrence of acute recurrent as well as chronic instability of the elbow articulation.

Methods: Fifty-six consecutive patients with fracture-dislocations of the elbow were reviewed. There were an equal number of males and females. The average age was 47 years (range 17 to 82). The injury pattern was anterior in 11 patients (20%) and posterior in 45 patients (80%). Among the anterior fracture-dislocations (AFD), all involved a fracture of the olecranon process (many extending into the ulnar shaft) and 6 (54%) had a separate fracture fragment representing nearly the entire coronoid. Fifteen (33%) of the posterior injuries were associated with fracture of the olecranon: 14 of these were intraarticular posterior Monteggia (PM) injuries with a large fracture of the coronoid process, and all but 2 had a comminuted fracture of the radial head. Among the 30 posterior fracture-dislocations without associated fracture of the olecranon there were 29 with associated fracture of the radial head (PRH; 86% comminuted) and 13 (41%) of these had associated fracture of the coronoid (PRHC)in most cases representing less than 50% of the coronoid height. All but 1 of the large and none of the smaller (< 50%) coronoid fractures were secured with screws entering through the dorsal aspect of the ulna. Among the fractures of the radial head, 19 were treated with internal fixation, 6 with prosthetic replacement, 9 with partial or complete excision and 8 were not addressed.

Results: Nine patients (16%) had one or more redislocations within one month of the initial treatment. This was related to lack of fixation of a coronoid fracture in 7 patients (with failure to restore the radial head contributing in 3), radial head excision in 1 patient, and insufficiency of the lateral collateral ligament complex in 1 patient. In particular, 5 of 13 (39%) patients with PRHC had acute recurrent instability. At an average follow-up of 26 months, early arthrosis suggestive of chronic instability had developed in 1 (9%) patient with AFD, 4 patients (29%) with PM, 5 (31%) patients with PRH, and 8 (62%) patients with PRHC.

Conclusions: Acute and chronic elbow instability following fracture-dislocation is related to a failure to restore sufficient osseous/articular stability to the elbow. Fracture-dislocations occur in a limited number of easily recognizable patterns, the characteristics of which help to guide treatment. Smaller coronoid fractures (<50%) are common among posterior fracture-dislocations without fracture of the olecranon, and many of these may need to be repaired in order to restore the anterior component of elbow stability.