Heterotopic ossification after cervical disc replacement: clinical significance and radiographic analysis. A prospective study.

Limited data is available regarding heterotopic ossification (HO) after cervical disc replacement (CDR). The goal of this study was to determine the incidence of HO after CDR with the Mobi-C artificial disc to identify the risk factors for HO, and to investigate whether HO affects clinical outcome and range of motion (ROM). Seventy one patients were included in this study. The mean follow-up was 21 months. Radiological evaluation included grading of HO and assessment of ROM for each level treated. HO was detectable in 23 treated segments (27.7%). The mean ROM was 8.1 degrees preoperatively and increased to 10.2 degrees at the last follow-up visit. Nevertheless, HO did not appear to affect clinical outcomes. HO appears to be a common complication after CDR. No specific risk factors have been clearly identified in our study. Long-term follow-up will be needed to assess the clinical significance of HO.