[Acetabular implant in Charnley's total arthroplasty. Review of 309 cases with a minimum of 15 years follow-up].
OBJECTIVE
The aim of this study was to appreciate the long term result of 309 acetabular components of total hip arthroplasty.


METHODS
All were performed using Charnley's prosthesis and cement, by one surgeon, between January 1972 and December 1975. Clinical function was graded according to Postel-Merle-d' Aubigné's scoring system (PMA score). We measured wear of polythylene using a personal method, on anteroposterior radiographs of the pelvis. Radiolucent line were appreciated by Delee and Charnley's criteria, migration by Massin's criteria. Survivorship curves were calculated with radiolucent lines, as migration, on 15 years. We compared the effect of different parameters on wear and loosening of the sockets.


RESULTS
At 15 years follow-up, we found 51.5 per cent hips with the highest PMA score (18). Revision for socket loosening was 3.88 per cent, the same for dislocations. Concerning 25 per cent of the sockets, wear of polyethylene was evaluated less than 0.065 mm a year, concerning 50 per cent of them, it was evaluated less than 0.11 mm a year, at last concerning 75 per cent of them, it was evaluated less than 0.16 mm a year. No significant correlation was established between the tilt of the acetabular component and the wear of polyethylene. We observed no radiolucent lines for 60 per cent of the implants, nor migration for 83 per cent of them. Statistical analysis proved the influence of the wear on radiolucent lines and migration.


CONCLUSIONS
The analysis confirms a moderate wear of polyethylene during 15 years. We introduce an original method for its measurement and its formulation. This method allows a truly description of wear in long term results. This analysis confirms also that several parameters intercede on loosening; these are different if one considers radiolucent lines or migration. We do think at last, that the best positionning of the socket in the A.P. view should approach 35 degrees.
Avedikian
J
J
Service de Chirurgie Orthopédique et Traumatologique, CHU Poitiers, BP 577.
Soyer
J
J
Dumez
J F
JF
Muller
A
A
Pries
P
P
Clarac
J P
JP
D000077:Acetabulum / Q000000981:diagnostic imaging / Q000601:surgery*; D000368:Aged; D000369:Aged, 80 and over; D005500:Follow-Up Studies; D006622:Hip Prosthesis / Q000009:adverse effects / Q000379:methods*; D006801:Humans; D011095:Polyethylenes; D011475:Prosthesis Failure; D011859:Radiography; D016019:Survival Analysis
D011095:Polyethylenes
L'implant cotyloïdien dans l'arthroplastie totale de Charnley. Revue de 309 dossiers avec un recul minimum de 15 ans.