How Does the Direct Anterior Approach Compare with Other Surgical Approaches to THA?
To help surgeons provide patients with a balanced overview of the literature surrounding surgical approaches to total hip arthroplasty, the authors review studies on the reported benefits and potential complications of the direct anterior approach versus other approaches.
Alex Gaukhman, MD; Simon Garceau, MD; Ran Schwarzkopf, MD, MSc; and James Slover, MD, MS
Total hip arthroplasty (THA) has been called the “surgery of the century,” yet surgeons continue to look for ways to improve patient outcomes and reduce complications. Over the past 20 years, the direct anterior approach (DAA) for THA has become increasingly common and sought after by patients wanting a quicker recovery and improved function. However, there is scant evidence in the literature as to whether any approach is truly superior or can be termed the new “gold-standard” for THA
The DAA is not a new procedure, and it is helpful to understand the evolution of the approach from its beginnings through the 21st century. German surgeon Carl Hueter first described the DAA in the Compendium of Surgery in 1881.  In 1917, Norwegian-born orthopaedic surgeon Marius Nygaard Smith-Peterson began utilizing the DAA at Massachusetts General Hospital, typically for open reduction of congenital hip dislocations in children and for mold arthroplasty in adults. 
Although the approach was gaining traction in the US and Europe, it was supplanted by the advent of Charnley’s low-friction arthroplasty hips, which became popular due to the reproducibility of the procedure.  The DAA remerged in the early 2000s with the added benefit of a specialized fracture table to help with exposure. In 2005, Matta el al  described success with the DAA in 437 patients, and since then, there has an increase in utilization and popularity of the DAA in the US.
Trends and Utilization
Marketing and promotion of the DAA by hospitals, surgeons, and industry has played a role in driving the popularity of the approach. Internet promotion has become a common means of advertisement. Approximately 23% of members of the American Association of Hip & Knee Surgeons (AAHKS) promote the DAA on their personal websites, quoting advantages such as quicker recovery and decreased pain as major benefits.  Fewer than 5% of websites mention potential complications.
Despite this widespread advertisement of the DAA on the internet, a 2015 study found that only 28% of THA patients at Mayo Clinic had heard of the DAA, with most of these patients learning about it from friends and family (58%) or healthcare professionals (39%).  The internet was cited by only 19% of respondents. 
A 2019 study of AAHKS members found that surgeons who perform the DAA are typically younger and have spent less time in practice than surgeons who do not offer the approach.  Non-DAA surgeons perceive the DAA as resulting in worse outcomes, and they are concerned with the learning curve.  Numerous studies have indicated that surgeons need to perform 50 to 100 cases in the learning curve before they will see no difference in the cumulative percent revision rate and other complications. [6,7] Mastering exposure of the femur is typically regarded as the toughest aspect of the approach.
It is the responsibility of the orthopaedic community to provide patients with a balanced overview of the literature surrounding surgical approaches to THA to ensure informed patient-decision making prior to THA. The discussion below outlines reported benefits and potential complications of the DAA.
Reported advantages of the DAA include:
- Supine positioning during the procedure
- Fluoroscopic image intensifications
- Improved function and pain control after surgery
Much of the benefits are related to the nature of the approach and the lack of muscle disruption as compared with other approaches.
Miller et al  performed a systematic review and meta-analysis analyzing outcomes reported through the 90-day postoperative period following THA by the DAA. Nine studies reported less pain, 5 studies reported less narcotic usage, and 8 studies reported improved Harris Hip Scores with the DAA. No differences in complications were observed between the DAA and the posterior approach. 
A single-surgeon, randomized study examined outcomes in patients who underwent DAA THA versus those who underwent posterior approach THA. The researchers noted that patients in the DAA group had shorter lengths of stay, earlier discontinuation of assistive devices (almost 10 days earlier), and improved pain scores. All parameters equalized at 6 weeks postoperatively. 
Cheng et al  compared early outcomes of the DAA and the posterior approach in a 2-surgeon, prospective, randomized study of 72 patients (35 DAA, 37 posterior approach). They observed no differences in Western Ontario McMasters Arthritis Index, Oxford Hip Score, EuroQoL, 10-meter walk test, and gait usage between groups. They performed a subgroup analysis for 1 of the surgeons and found that patients in the DAA group left the hospital sooner, had lower opiate use at 2 weeks after surgery, and had smaller wounds. However, these patents also had more intraoperative blood loss and weaker hip flexion at 2 and 6 weeks. No differences were noted in component positioning or complications between groups. 
Taunton et al  saw no difference in complications or leg length among 54 patients randomized to either the DAA or the mini-posterior approach. Patients in the DAA group had a faster median time to ambulation without an assistive device (6 days earlier than the mini-posterior group; 22 vs 28 days; P=0.04). 
In summary, the DAA showed a slightly greater advantage for patients in the early postoperative period. However, outcomes between the DAA and the posterior or mini-posterior approach were similar thereafter.
Complications and Adverse Events
Another aspect that must be weighed is the complication profile associated with a particular surgical approach to THA. Major complications after THA, although generally uncommon regardless of the approach selected, can have life-altering repercussions for patients and result in a significant burden to the healthcare system.
In 2 retrospective cohort studies, Aggarwal and colleagues from NYU Langone Health compared the risk of major complication among various surgical approaches to THA, attempting to exclude surgeons in the learning curve for the DAA. [15,16] In the first study of 3574 patients, the DAA was associated with a higher reoperation rate (4.7%) than the other surgical approaches commonly used at their institution.  Similarly, they compared deep infections in a DAA cohort of 1985 patients and a non-DAA cohort of 4101 patients and found a significantly greater number in the DAA cohort (1.22% vs 0.63%; P=0.023). 
Pincus et al  assessed risk of major surgical complications of THA in a large population-based cohort study, propensity-score matching 2993 patients who had undergone THA by the DAA with 2993 patients who had undergone THA by the posterior or lateral approaches. Patients were followed for 1 year postoperatively. The most important findings of this study were that the DAA was associated with an approximately 3-fold greater risk of deep infection, and a 2-fold greater risk of revision and dislocation compared with other surgical approaches.
In summary, the DAA may be associated with a slightly higher risk for major complications, most notably deep infection, relative to other approaches. This emerging evidence should be weighed by surgeons and discussed with patients.
To properly evaluate the literature pertaining to DAA THA, it is important to assess for the presence of bias. Without such critical assessment, results can misleadingly suggest superiority of one approach over another.
For example, the 2019 annual report of the Australian Registry showed that the DAA was used more often in younger, healthier patients with lower BMIs compared with the posterior or lateral approach.  Although registry data may provide power in numbers, the concept of statistical power is irrelevant if the study or dataset is biased at baseline.
One method of addressing bias is through randomization. In 2018, Taunton et al  published the results of their John Charnley Award-winning randomized clinical trial comparing functional recovery in 52 DAA patients versus 49 mini-posterior patients. The researchers concluded that the DAA leads to slightly better early function compared with the mini-posterior approach, but the advantage disappears by 2 months after surgery.
The following year, Sauder et al  won the AAHKS Clinical Research Award for their study of the effect of surgical approach on patient-reported outcome measures after THA. In an attempt to deal with potential bias, they performed risk-adjustment through propensity-matched scoring of patients who had undergone THA through the DAA or the posterolateral approach (100 patients per group). Their results contradicted Taunton et al : At the postoperative visit (mean of 47 days), the posterolateral approach patients had slightly better early function compared with the DAA patients, although the difference did not persist. 
Such conflicting results highlight an important point: When enough studies are performed with small sample sizes assessing small effects, contradictory results can occur. Moreover, this is possible even when randomization of patients is performed. In fact, even large randomized controlled trials may be limited due to the inability to blind surgeons and patients.
Studies have reported positive results favoring early recovery with the DAA, as have conflicting studies favoring other approaches. Variation in results may reflect small differences between surgical approaches rather than a true clinically important benefit. Surgical approach is one element in the treatment of patients undergoing THA; other elements in the perioperative care likely play a significant role as well. From the current available evidence, orthopaedic surgeons should feel confident using the approach that is most facile for them.
Alex Gaukhman, MD, and Simon Garceau, MD, are NYU/ISK Adult Reconstruction Fellows at NYU Langone Health, New York, New York. Ran Schwarzkopf, MD, MSc, and James Slover, MD, MS, are from the Division of Orthopedics, Adult Joint Reconstruction, at NYU Langone Health, New York, New York.
Disclosures: The authors have disclosures relevant to this article.
- Rachbauer F, Kain MS, Leunig M. The history of the anterior approach to the hip. Orthop Clin North Am. 2009;40(3):311-20.
- Matta JM, Shahrdar C, Ferguson T. Single-incision anterior approach for total hip arthroplasty on an orthopaedic table. Clin Orthop Relat Res. 2005;441:115-24.
- Shofoluwe AI, Naveen NB, Inabathula A, et al. Internet Promotion of Direct Anterior Approach Total Hip Arthroplasty by Members of the American Association of Hip and Knee Surgeons. J Arthroplasty. 2018;33(1):167-70.e1.
- Trousdale WH, Taunton MJ, Mabry TM, Abdel MP, Trousdale RT. Patient perceptions of the direct anterior hip arthroplasty. J Arthroplasty. 2017;32(4):1164-70.
- Patel NN, Shah JA, Erens GA. Current Trends in clinical practice for the direct anterior approach total hip arthroplasty. J Arthroplasty. 2019;34(9):1987-93.e3.
- Spaans AJ, van den Hout JA, Bolder SB. High complication rate in the early experience of minimally invasive total hip arthroplasty by the direct anterior approach. Acta Orthop. 2012;83(4):342-6.
- de Steiger RN, Lorimer M, Solomon M. What is the learning curve for the anterior approach for total hip arthroplasty? Clin Orthop Relat Res. 2015;473(12):3860-6.
- Miller LE, Gondusky JS, Bhattacharyya S, Kamath AF, Boettner F, Wright J. Does surgical approach affect outcomes in total hip arthroplasty through 90 days of follow-up? a systematic review with meta-analysis. J Arthroplasty. 2018;33(4):1296-302.
- Christensen CP, Jacobs CA. Comparison of patient function during the first six weeks after direct anterior or posterior total hip arthroplasty (tha): a randomized study. J Arthroplasty. 2015;30(9 Suppl):94-7.
- Cheng TE, Wallis JA, Taylor NF, Holden CT, Marks P, Smith CL, et al. A Prospective randomized clinical trial in total hip arthroplasty-comparing early results between the direct anterior approach and the posterior approach. J Arthroplasty. 2017;32(3):883-90.
- Taunton MJ, Mason JB, Odum SM, Springer BD. Direct anterior total hip arthroplasty yields more rapid voluntary cessation of all walking aids: a prospective, randomized clinical trial. J Arthroplasty. 2014;29(9 Suppl):169-72.
- AOANJRR. Hip, Knee & Shoulder Arthroplasty: 2019 Annual Report. Adelaide: AOA; 2019.
- Taunton MJ, Trousdale RT, Sierra RJ, Kaufman K, Pagnano MW. John Charnley Award: Randomized clinical trial of direct anterior and miniposterior approach tha: which provides better functional recovery? Clin Orthop Relat Res. 2018;476(2):216-29.
- Sauder N, Vestergaard V, Siddiqui S, et al. The AAHKS Clinical Research Award: No evidence for superior patient-reported outcome scores after total hip arthroplasty with the direct anterior approach at 1.5 months postoperatively, and through a 5-year follow-up. J Arthroplasty. 2020;35(6S):S15-S21.
- Aggarwal VK, Elbuluk A, Dundon J, et al. Surgical approach significantly affects the complication rates associated with total hip arthroplasty. Bone Joint J. 2019;101-B(6):646-51.
- Aggarwal VK, Weintraub S, Klock J, et al. 2019 Frank Stinchfield Award: A comparison of prosthetic joint infection rates between direct anterior and non-anterior approach total hip arthroplasty. Bone Joint J. 2019;101-B(6_Supple_B):2-8.
- Pincus D, Jenkinson R, Paterson M, Leroux T, Ravi B. Association between surgical approach and major surgical complications in patients undergoing total hip arthroplasty. JAMA. 2020;323(11):1070-6.