title: Heterotopic ossification after total hip arthroplasty: our experience.
abstract: Heterotopic ossification is a condition characterized by the presence of mature lamellar bone and often bone marrow in soft tissues surrounding a major joint. It represents a common complication after total hip arthroplasty (THA). The etiology and predisposing factors are not completely known, but some authors reported that the implant of a non-cemented prosthesis seems to be associated with a greater incidence of HO. Two hundred and two non-cemented total hip arthroplasties were performed between October 1997 and February 2002. The mean age was 70.2 years. The average follow-up for 181 hips included in the study was 96 months (range, 72-120 months). A standard lateral approach (Hardinge) was performed for the implant of a non-cemented femoral component and a non-cemented acetabular component. Radiographs were done before and after surgery, at 1, 4 and 12 months postop, then every year. The incidence of HO was assessed in the antero-posterior view at each interval and graded according to Brooker classification. Out of 181 implants, HO was observed in 52 hips (28,7%). Heterotopic bone was graded as class I in 32 (17.7%) hips, class II in 14 (7.73%) hips, class III in 6 (3,3%) hips and class IV in none (0%). The mean preoperative Harris hip score was 48; at the last follow-up, the mean postoperative score was preoperatively to a mean of 89 points (range, 76-97 points) in HO Hip and of 91 points (range, 78-100 points) in the other Hip. In our experience, non-cemented THA led to a higher incidence of class I and II HO according to Brooker Classification, the incidence of HO is comparable to the rates reported in recent studies about the HO finding after a non-cemented THA, the importance of clinical symptoms in the presence of HO is very low.
authors.affiliation: 2nd Unit of Orthopaedic and Trauma, University of Bari, Bari, Italy. antonio.spinarelli@libero.it
authors.forename: A
authors.initials: A
authors.lastname: Spinarelli
authors.forename: V
authors.initials: V
authors.lastname: Patella
authors.forename: M
authors.initials: M
authors.lastname: Petrera
authors.forename: A
authors.initials: A
authors.lastname: Abate
authors.forename: V
authors.initials: V
authors.lastname: Pesce
authors.forename: S
authors.initials: S
authors.lastname: Patella
mesh_terms: D000368:Aged; D001172:Arthritis, Rheumatoid / Q000601:surgery; D019644:Arthroplasty, Replacement, Hip / Q000009:adverse effects*; D005260:Female; D005265:Femoral Neck Fractures / Q000601:surgery; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D007558:Italy / Q000453:epidemiology; D008297:Male; D009999:Ossification, Heterotopic / Q000000981:diagnostic imaging / Q000453:epidemiology / Q000209:etiology*; D010003:Osteoarthritis / Q000601:surgery; D011474:Prosthesis Design; D011859:Radiography; D012189:Retrospective Studies; D012307:Risk Factors; D012720:Severity of Illness Index