Background: From 1992 to 1996, we performed 541 cementless total hip
arthroplasties using a Duraloc 100 acetabular component with an apex hole
eliminator that did not have a positive stop design. During routine follow-up
radiographic evaluation, we noted several hips with advanced or separated hole
eliminators. This study presents the clinical consequences of this occurrence
and its relationship to polyethylene wear and osteolysis.
Methods: A total of 541 hips (358 with a minimum duration of
follow-up of five years) were evaluated clinically with use of the method of
Merle D'Aubigné and Postel. Anteroposterior pelvic and iliac oblique
radiographs were used to evaluate polyethylene wear, osteolysis, hole
eliminator position, and component stability.
Results: Nineteen hips that had been followed for an average of
eighty-nine months showed advancement or complete separation of the hole
eliminator on radiographic evaluation. In most hips, advancement of the hole
eliminator was visible on only the iliac oblique radiograph. In all but one
hip with separation of the hole eliminator, complete plug separation was
detectable on both the iliac oblique and anteroposterior pelvic radiographs.
No association was found between polyethylene wear and either advancement or
separation of the hole eliminator. No osteolysis was visible radiographically
in the hips with hole eliminator advancement, but osteolysis was always
visible in the hips that had complete separation of the hole eliminator.
Conclusions: The hole eliminator has been redesigned since November
1995 to prevent possible advancement. However, patients with earlier designs
should be followed carefully because advancement or separation can be expected
in about 5% of the patients who have been followed for a minimum of five
years. Despite this complication, which is seen radiographically, all patients
were satisfied with the function of the hip. We do not recommend surgery
solely to remove or replace the hole eliminator.
Level of Evidence: Therapeutic study, Level IV (case
series [no, or historical, control group]). See Instructions to Authors for a
complete description of levels of evidence.