The effect of adjuvant calcium phosphate coating on a porous-coated femoral stem.
A prospective, randomized, double-blind, multicenter trial was done to determine if the addition of hydroxyapatite and tricalcium phosphate to the porous coating of a cementless femoral component would result in improved clinical and radiographic outcomes. Patients were randomized to receive identical porous-coated stems with (n = 159 hips) or without (n = 159 hips) hydroxyapatite and tricalcium phosphate coating. At 2 to 5 years followup (mean, 37 months), no implants were revised for aseptic loosening. There was no difference in clinical function between the two groups with respect to the Harris hip score or Western Ontario and McMaster Universities Osteoarthritis Index scores. Bony ingrowth occurred frequently in both groups with 99% of the hydroxyapatite and tricalcium phosphate group and 98% of the control group showing radiographic evidence of osseointegration. Implants coated with hydroxyapatite and tricalcium phosphate had significantly fewer radiolucencies adjacent to the porous coating, indicative of improved osseointegration. Radiolucencies were present in Gruen Zones 1, 7, 8, or 14 in 25% of the control group and in 7% of the hydroxyapatite and tricalcium phosphate group. This improved osseointegration could serve as an added barrier to particulate debris migration and increase the long-term survivorship of the implant.
Tanzer
Michael
M
Division of Orthopaedic Surgery, McGill University, Montreal General Hospital, 1650 Cedar Avenue, #B5.159, Montreal, Quebec, Canada H3G 1A4. mtanz@canada.com
Gollish
Jeffrey
J
Leighton
Ross
R
Orrell
Kevin
K
Giacchino
Alan
A
Welsh
Peter
P
Shea
Beverley
B
Wells
George
G
D002130:Calcium Phosphates; D004311:Double-Blind Method; D005260:Female; D006622:Hip Prosthesis; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D011474:Prosthesis Design; D013499:Surface Properties
D002130:Calcium Phosphates; C020243:calcium phosphate