To The Editor:
I read with interest "Elbow Stiffness Following Malunion of a Fracture of the Lateral Epicondyle of the Humerus in a Child. A Case Report" (2002;84:818-21), by Zionts and Mirzayan. Although the authors did not discuss any postulated mechanism of injury for this fracture, we have observed a number of similar injuries in adults. A fracture of the lateral epicondyle and/or condyle often occurs as an avulsion during an episode of instability of the elbow in which the lateral ulnar collateral ligamentous complex avulses a fragment of bone. In our series, treatment consisted of fixation of this fragment of bone, which is important because of its soft-tissue attachments. I wonder if the authors would be so kind as to describe their operative experience in slightly more detail. For example, what soft-tissue structures did they find attached to this fragment? How did they deal with the soft-tissue structures following fragment excision? Was any predilection for instability of the elbow noted intraoperatively after fragment excision?
On a separate note, it can be quite difficult to detect subtle forms of elbow instability clinically. A failure to obtain adequate soft-tissue healing in their patient could predispose the elbow to posterolateral rotatory instability. In a similar vein, we have noted valgus instability of the elbow following nonunion of avulsion fractures of the medial epicondyle in adults
1 . In many of our patients, this problem went undiagnosed for a number of years following their injury. Could the authors elaborate on the clinical examination of their patient, and were any specific tests for posterolateral rotatory instability performed?
Finally, in regard to indications for primary surgical intervention in patients with such an injury, it is unlikely that detailed clinical recommendations can be made on the basis of existing data since these injuries are relatively rare. However, it would seem that the treating surgeon should keep in mind the possibility that underlying instability of the elbow associated with such an avulsion would be a relative indication for operative fixation of the associated fracture.
R. Mirzayan and L.E. Zionts reply:
We thank Dr. McKee for his interest in our case report and for his thoughtful and astute questions. The lateral epicondyle serves as the attachment of the extensor muscle mass and the lateral collateral ligament. We mentioned in our paper that fractures of the lateral epicondyle are thought to be the result of a varus strain on the elbow. Tears of the ligament, specifically of the lateral ulnar collateral ligament, can lead to posterolateral rotatory instability of the elbow
2 . The symptoms of lateral rotatory instability are vague but can include pain and the feeling of instability of the elbow. Our patient did not report any of these symptoms at her one-year follow-up visit. To our knowledge, this condition has not been described in children.
The surgical procedure involved a subperiosteal elevation of the soft tissues attached to the lateral epicondyle with use of electrocautery. Once the lateral epicondyle was excised, the soft tissues were repaired down to the bone just proximal to the lateral condyle with an absorbable braided suture. A test for posterolateral rotatory instability could not be performed with the patient under anesthesia because of the limitation of elbow motion at the time of the operation. We believe that the repaired soft tissues healed adequately postoperatively because the patient did not complain of any elbow pain and had no symptoms of instability at her last follow-up visit. No specific tests for posterolateral rotatory instability of the elbow were performed.
Although our patient reported no subsequent problems with her elbow, we agree with Dr. McKee that underlying instability of the elbow should be considered a possibility in individuals who have sustained a displaced fracture of the lateral epicondyle of the humerus. Because these fractures heal readily in children, we have recommended that, in these young patients, operative treatment be performed only when the fragment is displaced posteriorly or inferiorly by =5 mm to avoid the possibility of residual elbow stiffness.