Uncemented cups with and without screw holes in primary THA: a Swedish Hip Arthroplasty Register study with 22,725 hips

No Difference in Survivorship Following Primary Total Hip Arthroplasty Using Ultraporous Acetabular Cups and Cross-Linked Polyethylene With and Without Acetabular Screws in a Large United States Health Care System

BACKGROUND

Modern cementless acetabular cups for total hip arthroplasty (THA) typically have screw options. Historically, screws were thought to improve stability, but came at the cost of pathways for osteolysis. Modern cups and liners may have made both concerns obsolete, and the utility of screws are now contested. We sought to determine modern implant survivorship relative to screw use.

METHODS

We conducted a cohort study. A US health care system's Total Joint Replacement Registry was used to identify patients ≥ 18 years who underwent uncomplicated primary THA for osteoarthritis (2010 to 2021) with an ultraporous cup and cross-linked polyethylene liner, with or without one to two acetabular screws. The primary outcome was acetabular revision for aseptic loosening. Secondary outcomes were aseptic revision for acetabular fracture and any revision for acetabular/femoral loosening and periprosthetic fracture. Multiple Cox proportional hazard regression was used to evaluate revision risk. There were 46,785 THAs identified. Screw use declined from 65.3 to 49.9%.

RESULTS

No difference was observed in 10-year revision risk for acetabular loosening (0.2 versus 0.1%, hazard ratio 1.97, 95% confidence interval = 0.84 to 4.59, P = 0.119). There was one revision for acetabular fracture with and three revisions without screws. There was no difference in risk of overall acetabular or femoral revision, loosening, or periprosthetic fracture. There remained no difference in acetabular-sided loosening between routine screw users and nonusers (0.15 versus 0.06%, hazard ratio 1.26, 95% confidence interval 0.42 to 3.75, P = 0.683).

CONCLUSIONS

In this study of survivorship following routine uncomplicated primary THA with modern cups and liners, screw usage patterns were associated with neither an advantage nor disadvantage - neither screw usage nor avoidance was associated with differences in acetabular loosening revision risk. Screw use was not associated with harm but remains debatable if there is an added benefit.

LEVEL OF EVIDENCE

Level III.

How to Prevent Aseptic Loosening in Cementless Arthroplasty: A Review

Aseptic loosening is the main late postoperative complication of cementless total hip arthroplasties (THAs), leading to pain and functional impairment. This article aims to update the orthopedic surgeon on the various methods by which the aseptic loosening rate can be reduced. We performed a systematic review by searching the PubMed database for hip aseptic loosening. We included meta-analysis, randomized controlled trials, reviews, and systematic reviews in the last 10 years, which provided information on techniques that can prevent aseptic loosening in total hip arthroplasty. From a total of 3205 articles identified, 69 articles (2%) met the inclusion criteria, leading to a total of 36 recommendations. A lot of research has been conducted in terms of septic loosening in the last decade. Currently, we have various techniques by which we can reduce the rate of aseptic loosening. Nevertheless, further randomized clinical trials are needed to expand the recommendations for aseptic loosening prevention.

Acetabular screws do not improve early revision rates in primary total hip arthroplasty. An instrumented registry analysis

BACKGROUND

Initial stability of uncemented acetabular components in total hip arthroplasty (THA) is important for osseointegration and potentially enhanced by screw fixation. We used Australian Orthopaedic Association National Joint Replacement Registry data to determine whether screw usage influences uncemented acetabular component survival.

METHODS

Primary THA with uncemented acetabular components performed for osteoarthritis from 1999 to 2018 was included. Survivorship was calculated using Kaplan-Meier estimates of cumulative percent revision (CPR). Comparisons used Cox proportional hazards method. An instrumental variable analysis adjusted for surgeon preference for screws as a confounding factor was used.

RESULTS

Three hundred thirty thousand one hundred ninety-two THAs were included (31.8% with screws, 68.2% without). Two hundred twenty thousand six hundred seven were included in the instrumental variable analysis. Revision rate of acetabular components (all causes) was higher with screws during the first six years (hazard ratio (HR) = 1.45 (95% CI 1.34, 1.57), p < 0.001) and lower thereafter (HR = 0.81 (95% CI 0.67, 0.98), p = 0.027). Revision rate of acetabular components for loosening was higher with screws over the entire study period (HR = 1.73 (95% CI 1.51, 1.98), p < 0.001). Overall THA revision rate was higher with screws during the first six years (HR = 1.20 (95% CI 1.15, 1.26), p < 0.001) but lower thereafter (HR = 0.89 (95% CI 0.81, 0.98), p = 0.020). Revision rate for dislocation was higher with screws over the entire period (HR = 1.16 (95% CI 1.06, 1.26), p < 0.001). Instrumental variable analysis revealed higher revision rates with acetabular screws in the first six years. (HR = 1.18 (95% CI 1.09-1.29), p < 0.001).

CONCLUSION

Screws did not confer a protective effect against acetabular loosening and were not associated with long-term negative consequences.