title: Fractures of distally-fixed femoral stems after revision arthroplasty.
abstract: We identified five (2.3%) fractures of the stem in a series of 219 revision procedures using a cementless, cylindrical, extensively porous-coated, distally-fixed femoral stem. Factors relating to the patients, the implant and the operations were compared with those with intact stems. Finite-element analysis was performed on two of the fractured implants. Factors associated with fracture of the stem were poor proximal bone support (type III-type IV; p = 0.001), a body mass index > 30; (p = 0.014), a smaller diameter of stem (< 13.5 mm; p = 0.007) and the use of an extended trochanteric osteotomy (ETO 4/5: p = 0.028). Finite-element analysis showed that the highest stresses on the stem occurred adjacent to the site of the fracture. The use of a strut graft wired over an extended trochanteric osteotomy in patients lacking proximal femoral cortical support decreased the stresses on the stem by 48%.We recommend the use of a strut allograft in conjunction with an extended trochanteric osteotomy in patients with poor proximal femoral bone stock.
authors.affiliation: Division of Orthopaedic Surgery, London Health Sciences Centre, University Campus, London, Ontario N65A 5A5, Canada. cbusch9965@aol.com
authors.forename: C A
authors.initials: CA
authors.lastname: Busch
authors.forename: M N
authors.initials: MN
authors.lastname: Charles
authors.forename: C M
authors.initials: CM
authors.lastname: Haydon
authors.forename: R B
authors.initials: RB
authors.lastname: Bourne
authors.forename: C H
authors.initials: CH
authors.lastname: Rorabeck
authors.forename: S J
authors.initials: SJ
authors.lastname: Macdonald
authors.forename: R W
authors.initials: RW
authors.lastname: McCalden
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D019644:Arthroplasty, Replacement, Hip / Q000379:methods*; D015992:Body Mass Index; D004812:Epidemiologic Methods; D005260:Female; D020342:Finite Element Analysis; D006622:Hip Prosthesis; D006801:Humans; D008297:Male; D008875:Middle Aged; D010027:Osteotomy; D011474:Prosthesis Design; D011475:Prosthesis Failure; D012086:Reoperation; D013314:Stress, Mechanical