Study finds high union rate with conservative treatment of isolated malleolus fractures

Only two cases of nonunion occurred among 57 fractures, which developed in patients with type C fractures, requiring open reduction and bone grafting.

Conservatively treating isolated medial malleolus fractures using cast immobilization can result in high rates of union and good functional outcomes, according to a study by researchers in Florida.

Dolfi Herscovici Jr., DO, and colleagues at the Florida Orthopaedic Institute, Tampa, reviewed the outcomes for 57 isolated medial malleolus fractures in 57 patients averaging 39.7 years of age.

In all cases, patients were treated with a short-leg, non-weight-bearing cast with the foot slightly inverted for 6 weeks. Once the cast was removed, patients were placed in walking boots and initiated physical therapy, according to the study, published in the British edition of the Journal of Bone and Joint Surgery.

The researchers modified the M?ller et al. and Paknovich and Shivaram classifications in order to group fractures into four patterns, as follows:

11 type A fractures: those with avulsions of the malleolus tip;
six type B fractures: those occurring between the malleolus tip and the level of the plafond;
29 type C fractures: those occurring at the level of the plafond; and,
11 type D fractures: those extending above the plafond level.

At a mean follow-up of 35.6 months, 55 of the 57 fractures achieved union.

At final follow-up, range of motion averaged 52.3° in combined dorsiflexion and plantar flexion. Scores for the SF-36 general health status scale averaged 48.1 points and American Orthopedic Foot and Ankle Society scores averaged 89.8 points, according to the study.

"There were no patients with medial instability, dermatological complications, radiological displacement or malalignment of the mortise and no evidence of post-traumatic arthritis," the authors said in the study.

Both cases of nonunion occurred in patients with type C fractures, and both cases achieved union by 4 months after undergoing open reduction and bone grafting, they noted.

The authors acknowledged that their study did not compare outcomes to a control group of surgically treated patients. "[But], given the results in our patients, a strong argument could be made for the conservative management of this injury regardless of the results in an operated group," they wrote.

"We feel that the operative management of patients presenting with a fracture of the medial malleolus should be reserved for bi- or trimalleolar injuries of the ankle, open fractures, injuries which compromise the shin or those involving the plafond, and for those patients who present with the development of painful nonunion," the authors said in the study.

For more information:
Herscovici D, Scaduto JM, Infante A. Conservative treatment of isolated fractures of the medial malleolus. J Bone Joint Surg Br. 2007;89-B:89-93.