title: Isolated fracture of the ceramic head after third-generation alumina-on-alumina total hip arthroplasty.
abstract: BACKGROUND
  While most reports of component fracture following alumina-on-alumina total hip arthroplasty have involved the acetabular liner, few have involved fracture of the alumina femoral head. In the present multicenter study, we investigated ceramic head fractures in a cohort of patients who underwent third-generation alumina-on-alumina total hip arthroplasty.
  
  
  METHODS
  We performed a retrospective study of 312 patients (367 hips) who underwent alumina-on-alumina total hip arthroplasty without cement at four participating centers with the use of a 28-mm BIOLOX forte femoral head and a BIOLOX forte liner from July 2001 to October 2003. Three hundred and five patients (359 hips) were evaluated at a mean of forty-five months postoperatively. Clinical follow-up with use of the Harris hip score and radiographic evaluation were performed at six weeks; at three, six, and twelve months; and every six months thereafter. Retrieved ceramic implants were examined by means of visual inspection.
  
  
  RESULTS
  Five hips (1.4%) in five patients were revised because of a ceramic head fracture during the follow-up period. The ceramic head fractures occurred during normal daily activities at a mean of 22.6 months postoperatively. A short neck had been used in all five hips in which a fracture occurred, compared with 121 (34.2%) of the 354 hips in which a fracture did not occur (p = 0.009). The fracture involved a circular crack along the circumference of the thinnest portion of the head component at the proximal edge of the bore. The fracture also involved multiple vertical cracks extending radially along the longitudinal axis from the circumference of the circular crack line to the lower edge of the head component.
  
  
  CONCLUSIONS
  In the present study, the rate of ceramic head fracture associated with one design of a short-neck modular alumina femoral head was 1.4% (five of 359). The extent to which these findings are generalizable to other designs that utilize this type of femoral head is unknown.
authors.affiliation: Department of Orthopaedic Surgery, Seoul National University College of Medicine, 28 Yeongeon-dong, Jongno-gu, Seoul 110-744, South Korea.
authors.forename: Kyung-Hoi
authors.initials: KH
authors.lastname: Koo
authors.forename: Yong-Chan
authors.initials: YC
authors.lastname: Ha
authors.forename: Woon Hwa
authors.initials: WH
authors.lastname: Jung
authors.forename: Sang-Rim
authors.initials: SR
authors.lastname: Kim
authors.forename: Jeong Joon
authors.initials: JJ
authors.lastname: Yoo
authors.forename: Hee Joong
authors.initials: HJ
authors.lastname: Kim
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D019644:Arthroplasty, Replacement, Hip / Q000009:adverse effects*; D005260:Female; D006622:Hip Prosthesis; D006801:Humans; D008297:Male; D008875:Middle Aged; D011475:Prosthesis Failure; D012189:Retrospective Studies