title: A prospective randomized study comparing electrochemically deposited hydroxyapatite and plasma-sprayed hydroxyapatite on titanium stems.
abstract: OBJECTIVE
  Plasma-sprayed hydroxyapatite (HA) is a successful coating for fixation of uncemented femoral stems. There may be alternative coatings with advantages in bone remodeling and transport of bone-active substances. We investigated whether an electrochemically deposited hydroxyapatite, Bonemaster (BM), might be a safe alternative in total hip arthroplasty. Our hypothesis was that the new coating would not be inferior to the conventional one.
  
  
  METHODS
  50 patients (55 hips) were included. The stem was tapered and porous-coated proximally. On top of the porous coating was either HA or BM. Patients were evaluated postoperatively and after 3, 6, 12, and 24 months to measure fixation by radiostereometric analysis (RSA), bone mineral density by dual-energy X-ray absorptiometry (DXA), and conventional radiography. Clinical evaluation was performed with Harris hip score and Oxford hip score, both preoperatively and after 2 years.
  
  
  RESULTS
  After 2 years, the stems had subsided 0.25 (HA) and 0.28 (BM) mm and there were no statistically significant differences between the groups in any direction, regarding both migration and rotation. The BM group retained significantly more bone than the HA group in Gruen zone 1 during the first 2 years. The Harris and Oxford hip scores were similar in both groups.
  
  
  CONCLUSIONS
  Electrochemically deposited hydroxyapatite on an uncemented stem does not appear to be inferior to plasma-sprayed HA regarding clinical and radiological results, bone remodeling, and micromotion after 2 years follow-up.
authors.affiliation: Department of Orthopaedics, Oslo University Hospital, Ullevål, Norway. berte2@mac.com
authors.forename: Berte Grimsmo
authors.initials: BG
authors.lastname: Bøe
authors.forename: Stephan M
authors.initials: SM
authors.lastname: Röhrl
authors.forename: Tore
authors.initials: T
authors.lastname: Heier
authors.forename: Finnur
authors.initials: F
authors.lastname: Snorrason
authors.forename: Lars
authors.initials: L
authors.lastname: Nordsletten
mesh_terms: D015502:Absorptiometry, Photon; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D019644:Arthroplasty, Replacement, Hip / Q000009:adverse effects / Q000379:methods; D015519:Bone Density; D016723:Bone Remodeling; D020099:Coated Materials, Biocompatible / Q000737:chemistry*; D017886:Durapatite / Q000737:chemistry*; D005260:Female; D005500:Follow-Up Studies; D006622:Hip Prosthesis; D006801:Humans; D008297:Male; D008875:Middle Aged; D015207:Osteoarthritis, Hip / Q000601:surgery; D011446:Prospective Studies; D011474:Prosthesis Design; D011475:Prosthesis Failure; D013499:Surface Properties; D014025:Titanium
chemical_list: D020099:Coated Materials, Biocompatible; D017886:Durapatite; D014025:Titanium