Total Ankle Arthroplasty Medial Malleolus Fractures and Use of Prophylactic Screw

Ankle arthritis is a debilitating condition that negatively impacts a patient's quality of life. The total ankle arthroplasty procedure continues to gain traction as a viable treatment option for end-stage ankle arthritis that has failed conservative treatment. Although newer total ankle models have shown improvement in complications and survivorship, intraoperative and postoperative medial malleolus fractures continue to be a concern.

We created two novel radiographic measurements of the bone bridge between the total ankle prosthesis and the tibial cortex. Using 72 patients, we analyzed the correlation between the bone bridge and intraoperative and postoperative fractures.

We found patients with no fractures had a larger transverse and short bone bridge (12.67 ± 2.93 and 11.24 ± 2.7 mm, respectively) compared with patients who experienced an intraoperative or postoperative medial malleolus fracture. Although patients who received a prophylactic screw had a bone bridge that was over 4 mm smaller compared with the group with no fractures, it was successful in preventing further fractures.

We recommend that the surgeon consider placement of a prophylactic screw in patients with a transverse bone bridge of 12 mm or short bone bridge of 10 mm.