Fig. 1 Images captured during diagnostic arthroscopic examination prior to surgery of an ankle. A, With no cartilaginous lesions. B, With a severe lesion on the talar dome.
Courtesy of Sjoerd Stufkens, MD

AAOS Now

Published 11/1/2008
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Jennie McKee

Study finds possible predictor of OA after ankle fracture

Initial cartilage damage influences long-term outcomes

After surgical reduction of an ankle fracture, osteoarthritis (OA) may still develop in up to 50 per­cent of pa­tients. But is there a way to predict which patients will be affected?

According to Dutch researcher Sjoerd Stufkens, MD, and Swiss colleagues, a correlation exists between the cartilaginous lesions resulting from the fracture and long-term outcomes in patients.

Preliminary results of the study show that men and women with little or no initial cartilage damage in the joint have equally good long-term radiologic and clinical outcome scores. When initial cartilage damage deeper than 50 per­cent of the cartilage thickness was present, however, outcomes were less favorable.

Dr. Stufkens presented the results of his study at the American Foot and Ankle Society’s (AOFAS) annual meeting.

Malunion most important cause
Malunion as a result of incorrect reduction (either after conservative or operative treatment) is likely the most important factor causing posttraumatic in the tibiotalar joint, noted Dr. Stufkens.

“Little is known about other factors that may contribute to the development of OA in an ankle that has been optimally treated by open reduction and internal fixation,” he said. “These factors include ligamentous lesions leading to ligamentous instability, alignment in the coronal plane, development of arthrofibrosis, and cartilage damage.”

According to Dr. Stufkens, the literature suggests that evidence of cartilaginous lesions can be found during arthroscopic examination in up to 79 percent of patients directly after ankle fracture (Fig. 1).

“We hypothesized that the more extensive the damage to the cartilage, the higher the chance that OA would develop later on,” said Dr. Stufkens.

Fig. 1 Images captured during diagnostic arthroscopic examination prior to surgery of an ankle. A, With no cartilaginous lesions. B, With a severe lesion on the talar dome.
Courtesy of Sjoerd Stufkens, MD

Studying joint degeneration and lesions
The study involved a consecutive series of 288 patients surgically treated for ankle fractures between 1993 and 1997. All patients had a diagnostic arthroscopic examination prior to surgery to assess cartilaginous lesions, ligamentous lesions, and tendon injuries.

After a mean of 12.9 years (range, 11.3 – 14.8), researchers assessed 109 patients clinically (using the AOFAS hindfoot score) and radiologically (using the Kannus Arthritis Score) to compare the amount of joint degeneration with the severity and location of initial lesions. Excluded from the study were patients in whom systemic inflammatory disease had developed and those who had a suboptimal fracture reduction.

Deeper lesions lead to worse outcomes
There were 16 Weber A fractures (below the joint line), 73 Weber B fractures (at the joint level) and 18 Weber C fractures (above the joint level). Researchers found that 61.1 percent of patients had no clinical signs of ankle OA (AOFAS hindfoot score > 90), and 57.4 percent of patients had no radiological signs of ankle OA (Kannus Arthritis Score > 90).

Patients who had bi- and trimalleolar fractures also had significantly more cartilaginous lesions. Weber C fractures had more and worse initial cartilaginous lesions directly after trauma than Weber B fractures, which left the tibiofibular ligaments intact.

Most patients (92.5 percent) with combined lateral malleolus fractures and transverse medial malleolus fractures or deltoid ligament ruptures (Lauge-Hansen SE-4 fractures) had lesions. Among patients with less severe oblique or spiral fractures of the lateral malleolus (Lauge-Hansen SE-2 fractures), only 60.7 percent had lesions, most of which were superficial.

“We found that patients who had deeper lesions on the anterolateral talus had significantly worse clinical long-term outcomes,” said Dr. Stufkens. “We also found that patients with deep lesions on the medial malleolus had the worst clinical and radiological outcomes. Severity of the lesions on the lateral malleolus, however, did not correlate with outcomes.”

Severity is a clue
Because Dr. Stufkens and his colleagues noted that patients with deep cartilage lesions on the medial malleolus and anterolateral talus had the worst outcomes, they concluded that assessing the location and severity of initial cartilaginous lesions after ankle fracture may be helpful in determining long-term outcomes.

Dr. Stufkens was the presenter and an author of the study, “Predicting the development of posttraumatic osteoarthritis after anatomically reduced ankle fracture.” Beat Hintermann, MD, served as lead author of the study. Additional authors included Dr. Markus Knupp, MD, and Alexej Barg, MD. Dr. Hintermann has ties to New Deal; Drs. Stufkens, Knupp and Barg report no conflicts.

Jennie McKee is a staff writer for AAOS Now. She can be reached at mckee@aaos.org