title: Radiostereographic analysis of a shoulder surface replacement: does hydroxyapatite have a place?
abstract: Resurfacing of the humeral head is commonly used within the UK to treat osteoarthritis (OA) of the shoulder. We present the results of a small prospective randomised study of this procedure using the Global CAP prosthesis with two different coatings, Porocoat and DuoFix hydroxyapatite (HA). We followed two groups of ten patients with OA of the shoulder for two years after insertion of the prosthesis with tantalum marker beads, recording pain, Constant-Murley and American Shoulder and Elbow Surgeons (ASES) outcome scores, and using radiostereometric analysis to assess migration. The outcomes were similar to those of other series, with significant reductions in pain (p = 0.003) and an improvement in the Constant (p = 0.001) and ASES scores (p = 0.006). The mean migration of the prosthesis three months post-operatively was 0.78 mm (0.51 to 1.69) and 0.72 mm (0.33 to 1.45) for the Porocoat and DuoFix groups, respectively. Analysis of variance indicated that the rate of migration reached a plateau after three months post-operatively in both groups. At follow-up of two years the mean migration was 1 mm (sd 1 (0.25 to 3.32)); in the Porocoat group and 0.8 mm (sd 0.4 (0.27 to 1.45)) in the DuoFix HA group. Significant migration of the prosthesis was seen in one patient who had received an anterior humeral bone graft. This prosthesis was later revised after 2.7 years. The addition of a coating of HA to the sintered surface does not improve fixation of this prosthesis.
authors.affiliation: Wrightington Hospital, Upper Limb Research Unit, Wigan, UK.
authors.forename: D
authors.initials: D
authors.lastname: Nuttall
authors.affiliation: Wrightington Hospital, Upper Limb Research Unit, Wigan, UK.
authors.forename: A
authors.initials: A
authors.lastname: Birch
authors.affiliation: Wrightington Hospital, Upper Limb Research Unit, Wigan, UK.
authors.forename: J F
authors.initials: JF
authors.lastname: Haines
authors.affiliation: Wrightington Hospital, Upper Limb Research Unit, Wigan, UK.
authors.forename: I A
authors.initials: IA
authors.lastname: Trail
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D019643:Arthroplasty, Replacement / Q000379:methods*; D001672:Biocompatible Materials / Q000627:therapeutic use*; D017886:Durapatite / Q000627:therapeutic use*; D005260:Female; D005548:Foreign-Body Migration / Q000517:prevention & control; D006801:Humans; D007595:Joint Prosthesis; D008297:Male; D008875:Middle Aged; D059352:Musculoskeletal Pain / Q000517:prevention & control; D010003:Osteoarthritis / Q000601:surgery*; D011446:Prospective Studies; D011475:Prosthesis Failure; D059869:Radiostereometric Analysis; D012785:Shoulder Joint
chemical_list: D001672:Biocompatible Materials; D017886:Durapatite
keywords: Hydroxyapatite; Micromovement; Radiostereographic analysis; Shoulder; Shoulder surface replacement