Total Elbow Arthroplasty for Distal Humeral Nonunion

Introduction

Distal humeral nonunions occur frequently secondary to suboptimal fracture fixation in a comminuted fracture setting. Host factors such as smoking, osteoporosis, compromised soft tissue envelope, and noncompliance can also increase the chances of developing nonunion.

Nonunion usually occurs at the supracondylar level secondary to limited cancellous bone and comminution at this level. The elbow joint is usually stiff; therefore most of the motion occurs from the nonunion site. This leads to progressive resorption of bone at the nonunion site. Additionally, the failed implants continue to damage the bone because of pathologic motion within the bone, compromising the bone stock further ( Fig. 93.1 ).

Internal fixation is the treatment of choice whenever possible. Modern series have reported a high union rate when internal fixation is used, but the reoperation rate has remained high, and function is not always reestablished.

Elbow arthroplasty is an excellent surgical alternative for the salvage of distal humeral nonunions when fixation is considered to be impractical or expected to be associated with a high rate of failure. Although some theoretical interest has been expressed in the use of distal humeral hemiarthroplasty for nonunions, the associated stiffness and bone loss make it less attractive compared with the acute setting. Most patients requiring arthroplasty for a distal humeral nonunion will benefit from the use of a total elbow arthroplasty. A linked implant is preferred in this situation as the humeral attachments of the collateral ligaments are removed as part of the procedure. This chapter reviews the presentation, surgical technique, and outcomes of total elbow arthroplasty for distal humeral nonunion.

Rationale, Indications, and Contraindications

Joint replacement is a well-accepted treatment modality for fractures in other locations, such as the femoral neck or the proximal part of the humerus. The good track record of some elbow implants for patients with rheumatoid arthritis and other conditions prompted the use of elbow replacement for distal humeral nonunion. Elbow arthroplasty is indicated only in a select group of elderly patients who present with either preexistent symptomatic disease (e.g., a rheumatoid elbow) or low nonunions with substantial osteopenia and severe damage to the articular surface. It is contraindicated in the presence of infection, as well as in nonunions amenable to stable internal fixation and in patients with anticipated high physical demands. An associated nonunion of an olecranon osteotomy complicates the surgical technique but should not be considered a contraindication for the procedure.

When total elbow arthroplasty is used for the treatment of distal humeral nonunion, the procedure offers several advantages: the extensor mechanism may be left undisturbed, no postoperative protection is required, functional range of motion is relatively predictable, and pain and limited motion secondary to nonunion, malunion, or posttraumatic osteoarthritis are avoided. The main disadvantages are the risk of other implant-related complications and the need to limit upper extremity use to minimize polyethylene wear.

Surgical Technique