title: Durability of second-generation extensively porous-coated stems in patients age 50 and younger.
abstract: Early versions of uncemented femoral total hip stems were often associated with thigh pain thought to be due to micromotion between the implant and bone in the distal uncoated regions. An extensively coated stem was introduced in 1992 to reduce that risk. We therefore asked whether second-generation extensively porous-coated cementless femoral stems in patients younger than 50 years of age would (1) be durable in terms of revisions; (2) provide high functional scores and reduce thigh pain; and (3) show radiographic signs of durability, including a reduction in stress shielding. We prospectively followed all 100 patients (115 hips) age 50 and younger treated with primary cementless total hip arthroplasties using a second-generation extensively porous-coated femoral stem between June 1994 and December 1999. The average age was 39.6 years (range, 17-50 years). The stems were mated to cementless acetabular components. Ninety patients were followed for a minimum of 5 years (mean, 8.6 years; range, 5-10 years). One stem was revised after a periprosthetic fracture. None were revised for loosening and all stems demonstrated bony ingrowth at last followup. No acetabular shell was revised for loosening and none was radiographically loose. Six acetabular liners were revised for wear (three each were 22-mm and 26-mm heads). This second-generation extensively porous-coated stem was durable at 5- to 10-year followup in this young active population.
  
  
  METHODS
  Level IV, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.
authors.affiliation: University of Iowa, Iowa City, IA, USA.
authors.forename: Jennifer A
authors.initials: JA
authors.lastname: Moyer
authors.forename: Catherine M
authors.initials: CM
authors.lastname: Metz
authors.forename: John J
authors.initials: JJ
authors.lastname: Callaghan
authors.forename: David W
authors.initials: DW
authors.lastname: Hennessy
authors.forename: Steve S
authors.initials: SS
authors.lastname: Liu
mesh_terms: D000077:Acetabulum / Q000000981:diagnostic imaging / Q000601:surgery*; D000293:Adolescent; D000328:Adult; D000367:Age Factors; D019644:Arthroplasty, Replacement, Hip / Q000009:adverse effects / Q000295:instrumentation*; D020099:Coated Materials, Biocompatible; D005260:Female; D005269:Femur / Q000000981:diagnostic imaging / Q000601:surgery*; D006621:Hip Joint / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000601:surgery*; D006622:Hip Prosthesis; D006801:Humans; D008297:Male; D008875:Middle Aged; D010146:Pain / Q000209:etiology; D010147:Pain Measurement; D016062:Porosity; D011474:Prosthesis Design; D011475:Prosthesis Failure; D011859:Radiography; D020127:Recovery of Function; D012086:Reoperation; D012189:Retrospective Studies; D013314:Stress, Mechanical; D013499:Surface Properties; D013848:Thigh; D013997:Time Factors; D016896:Treatment Outcome; D055815:Young Adult
chemical_list: D020099:Coated Materials, Biocompatible