Comparing the Risk of Early Failure in THA by Surgical Approach
A recently published study suggests that the direct anterior approach is overall associated with more early revisions, in particular for early femoral loosening, compared with the lateral or posterior approach. Larger studies are needed to substantiate this study’s conclusions.
Omar A. Behery, MD, MPH, and Ajit Deshmukh, MD
Meneghini RM, Elston AS, Chen AF, Kheir MM, Fehring TK, Springer BD. Direct Anterior Approach: Risk Factor for Early Femoral Failure of Cementless Total Hip Arthroplasty: A Multicenter Study. J Bone Joint Surg Am. 2017 Jan 18;99(2):99-105. doi: 10.2106/JBJS.16.00060. PubMed PMID: 28099299.
The direct anterior approach for total hip arthroplasty (THA) has gained popularity in recent years, with proposed benefits of quicker recovery and return to activity and less postoperative pain.
The current literature, however, is inconclusive on the rates of intraoperative and early postoperative complications compared with other routinely used approaches for THA.
The authors of this study aimed to examine whether the direct anterior approach is associated with higher rates of early THA failure, early femoral component aseptic loosening, or early periprosthetic fracture and lower rates of early revisions for instability compared with other surgical approaches.
A retrospective review of data on direct anterior approach THAs performed between 2011 and 2014 at 3 institutions included 342 early revision THAs that occurred within 5 years of the primary THA. The authors analyzed the following data points using chi-squared test, ANOVA, and univariate and multivariate logistic regression models:
- Surgical approach: direct anterior, lateral, or posterior
- Type of femoral stem
- Time to failure
- Failure mechanism: femoral or acetabular loosening, early periprosthetic fracture, instability, or infection
In the sample, 38% of THAs were done by the direct lateral approach, 37.7% by the direct anterior approach, and 24.3% by the posterior approach. Patients undergoing direct anterior approach THA had lower average body mass index (BMI), were more likely to have Dorr A femurs, and were more likely to have a tapered wedge stem compared with patients who underwent a posterior approach THA.
The direct anterior approach was also associated with shorter average time to revision compared with lateral and posterior approaches (10 months, 17.2 months, and 14.5 months, respectively). It was also associated with the greatest proportion of early femoral failures (periprosthetic femoral fracture or loosening).
The direct anterior and posterior approaches had higher proportions of early acetabular failure than the direct lateral approach, as well as higher odds of revision for instability.
Direct anterior THA has gained popularity and is marketed to have benefits of improved hip stability and overall better outcomes than other approaches, without concurring evidence in the literature.
Current studies show equivocal findings between this approach and others on implant position, muscle damage, operative time, blood loss, fracture, dislocation, wound complications, pain, and functional outcomes. Many of these studies are single-center, limited surgeon cohorts, which may be inherently biased to the experience level of the involved surgeons, given a known learning curve associated with the direct anterior approach.
Moreover, there is a referenced increasing trend of early THA failures from 24% to 50% that may be associated with the development of new techniques in THA, including rising use of the direct anterior approach. This highlights the importance of this study in expanding upon the current literature.
The results of the analysis in this study suggest that the direct anterior approach is overall associated with more early revisions, in particular for early femoral loosening, compared with the lateral or posterior approach. Although the rate of early acetabular failure was lower with the direct anterior approach, early revisions for instability were just as frequent as with the posterior approach, suggesting the lack of advantage of the direct anterior approach with regard to dislocation.
There are a few important limitations to consider in this study:
- Given the retrospective design of the study, it is difficult to determine the true prevalence or risk of early THA failures associated with the direct anterior approach.
- The inclusion of 3 centers with multiple surgeons who have varying techniques, experience, and protocols implies multiple potentially uncontrolled confounders to the failure associations seen.
- It is known that good results with the direct anterior approach to THA come after an initial learning curve. This is likely an important factor affecting failure rates that was not controlled in this study.
Given the recent rise in popularity, as well as the publicly perceived theoretical advantages of the direct anterior approach to THA, surgeons must be cautious when setting patient expectations and explaining the risks of potentially higher early failure rates compared with other approaches.
Larger studies of prospective nature are needed to substantiate the conclusions of this study.
Omar A. Behery, MD MPH is an orthopaedic surgery resident at NYU Langone Medical Center – Hospital for Joint Diseases, New York, New York. Ajit Deshmukh, MD is an Assistant Professor of Orthopaedic Surgery, Division of Adult Reconstruction, Department of Orthopaedic Surgery, at NYU Langone Medical Center – Hospital for Joint Diseases, New York, New York. He is also an orthopaedic surgeon at the VA New York Harbor Healthcare System, New York, New York.