Anterior Heterotopic Ossification at the Talar Neck After Total Ankle Arthroplasty.

BACKGROUND

Recently, as total ankle arthroplasty (TAA) has been widely performed, its outcomes and complications have been reported. Heterotopic ossification (HO) after TAA has been reported in the posterior compartment of the ankle. We report on a series of HOs that developed in the anterior compartment of the ankle at the talar neck region after TAA.

METHODS

TAA was performed using the Hintegra and the Mobility in 54 ankles (Hintegra, 21 ankles; Mobility, 33 ankles) from 2004 to 2012. The outcome was assessed by visual analog scale (VAS), the American Orthopaedic Foot & Ankle Society (AOFAS) ankle-hindfoot score, patient satisfaction, and radiographic evaluation. The HO was confirmed on the lateral ankle view. HO in the anterior compartment of the ankle was classified based on a modification of the Brooker classification.

RESULTS

After TAA, 13 HOs developed in 12 of the 54 ankles. Six HOs developed in the anterior compartment, and 7 HOs developed in the posterior compartment. The majority of the anterior compartment HO (5/6) was observed in the Mobility group. There was no significant relationship between HO and the clinical outcomes (VAS score, P = .62; AOFAS score, P = .31; ankle range of motion, P = .31).

CONCLUSIONS

Besides the posterior ankle, the anterior compartment of the ankle in the talar neck region was demonstrated to be another potential area for HO after TAA. The development of anterior HO was strongly related to the wide exposure of the cancellous bony surface at the talar neck and therefore occurred more often with the Mobility than with the Hintegra prosthesis.

LEVEL OF EVIDENCE

Level III, retrospective comparative case series.