Session III - Upper Extremity
Fri., 10/8/04 Upper Extremity, Paper #16, 3:00 pm
Fracture-Dislocations of the Elbow: Replacement of the Fractured Radial Head with a Modular Metal Prosthesis
Purpose: Use of a metal radial-head prosthesis to help restore elbow stability after fracture-dislocation is appealing because internal fixation of complex fractures of the radial head is susceptible to both early and late failure. The newer modular prostheses are easier to size and implant, but their effectiveness has not been investigated.
Methods: A single surgeon treated 42 consecutive complex fractures of the radial head associated with a fracture dislocation of the elbow with a single type of modular metal radial head prosthesis; two patients were lost to follow-up, leaving 40 for evaluation. Twenty-two patients had posterior dislocation of the elbow and fracture of the radial head (16 with an associated fracture of the coronoid), 17 had a posterior olecranon fracture-dislocation, and one had fracture of the radial head and rupture of the medial collateral ligament with subluxation, but not complete dislocation of the elbow. All of the injured lateral collateral ligaments (all elbow dislocations, and two-thirds of the olecranon fracture-dislocations) were reattached to the lateral epicondyle with use of suture anchors or suture through drill holes. All of the coronoid and olecranon fractures were repaired. The medial collateral ligament was not repaired. Nine patients had subsequent surgery to address heterotopic bone, elbow contracture, ulnar neuropathy, or a prominent screw. One patient had the prosthesis removed after a deep infection.
Results: At an average follow-up of 2 years (range, 1 to 4), elbow motion averaged 120° of flexion, a 23° flexion contracture, 64° of pronation, and 53° of supination. Stability was restored to all elbows, and 36 patients achieved a good or excellent result according to the system of Broberg and Morrey. Three patients had slight opening of the lateral aspect of the ulnohumeral joint, but none had signs of capitellar wear on radiographs. Thirty-three patients (82%) had lucency around the stem of the prosthesis, but none had more than mild pain, and this was not specifically referable to the radial head.
Conclusions: Prosthetic replacement of the radial head helps restore elbow stability after fracture-dislocation of the elbow. The prosthesis serves as a spacer rather than a well-fixed prosthesis, and the radiographic lucencies appear to be inconsequential, at least in the short term. The major pitfall of prosthetic replacement of the radial head is implantation of a prosthesis that is too long (over stuffing of the joint).