Abstract
Abstract
Background
In revision surgery with significant segmental acetabular defects, adequate implant selection and fixation methods are critical in determining successful bony ingrowth. Commercially available total hip prosthesis manufacturers generally offer additional multi-hole options of acetabular shells with identical designs for use in revision THAs where screw holes configurations vary from product to product. This study aims to compare the mechanical stability of the two types of acetabular screw constructs for the fixation of acetabular components: spread-out and pelvic brim-focused configurations.
Methods
We prepared 40 synthetic bone models of the male pelvis. In half of the samples with acetabular defects, identical curvilinear bone defects were manually created using an oscillating electrical saw. On the right side, multi-hole-cups in which the direction of the screw holes are centered on the pelvic brim (brim-focused) and, on the left side, multi-hole-cups with the direction of the screw hole spread throughout the acetabulum (spread-out) were implanted into the pelvic synthetic bones. Coronal lever-out and axial torsion tests were performed with a testing machine, measuring load versus displacement.
Results
The average torsional strengths were significantly higher in the spread-out group over the brim-focused group regardless of the presence of the segmental defect of the acetabulum (p < 0.001). But for the lever-out strength, the spread-out group exhibited significantly higher average strength over the brim-focused group for the intact acetabulum (p = 0.004), whereas the results were reversed in the brim-focused group when the defects were generated (p < 0.001). The presence of acetabular defects reduced the average torsional strengths of the two groups by 68.66% versus 70.86%. In comparison, the decrease in the average lever-out strength was less significant for the brim-focused group than the spread-out group (19.87% vs. 34.25%) (p < 0.001).
Conclusion
Constructs of multi-hole acetabular cups with the spread-out screw holes configuration exhibited statistically better axial torsional strength and coronal lever-out strength. With the presence of posterior segmental bone defects, the spread-out constructs demonstrated significantly better tolerance to axial torsional strength. Still, they exhibited inverted results of higher lever-out strength in the pelvic brim-focused constructs.
Funder
National Research Foundation of Korea
the Technology Innovation Program of Korea
Publisher
Springer Science and Business Media LLC
Subject
Orthopedics and Sports Medicine,Surgery
Reference32 articles.
1. Burke D, Bragdon C, Lowenstein J. Mechanical aspects of the bone-porous surface interface under known amounts of implant motion: an in vivo canine study. Trans 39th Annu ORS. 1993;18:470.
2. Hadjari MH, Hollis JM, Hofmann OE, Flahiff CM, Nelson CL. Initial stability of porous coated acetabular implants: the effect of screw placement, screw tightness, defect type, and oversize implants. Clin Orthop Relat Res. 1994;307:117–23.
3. Richard Illgen I, Rubash HE. The optimal fixation of the cementless acetabular component in primary total hip arthroplasty. JAAOS-J Am Acad Orthop Surg. 2002;10:43–56.
4. Otten VT, Crnalic S, Röhrl SM, Nivbrant B, Nilsson KG. Stability of uncemented cups—long-term effect of screws, pegs and HA coating: a 14-year RSA follow-up of total hip arthroplasty. J Arthroplasty. 2016;31:156–61.
5. García-Rey E, García-Cimbrelo E, Cruz-Pardos A. Cup press fit in uncemented THA depends on sex, acetabular shape, and surgical technique. Clin Orthop Relat Res. 2012;470:3014–23.
Cited by
1 articles.
订阅此论文施引文献
订阅此论文施引文献,注册后可以免费订阅5篇论文的施引文献,订阅后可以查看论文全部施引文献