At the AAOS 2024 Annual Meeting in San Francisco, panelists of the Instructional Course Lecture (ICL) “Complications with the Anterior Approach to Total Hip Arthroplasty: Identification, Prevention, and Management” discussed the unique complications associated with the direct anterior approach to total hip arthroplasty (DAA THA) and strategies to reduce and manage them.

William Hamilton, MD, FAAOS, from the Anderson Orthopaedic Research Institute in Alexandria, Virginia, served as the session’s moderator. Michael J. Taunton, MD, FAAOS, professor of orthopaedics at Mayo Clinic in Rochester, Minnesota; Jeffrey Frandsen, MD, adult reconstruction fellow at OrthoCarolina in Charlotte, North Carolina; and Robert Gorab, MD, FAAOS, joint replacement and arthritis surgeon at the Orthopaedic Specialty Institute in Orange County, California, rounded out the expert panel.

Incision and infection management
To begin the session, Dr. Frandsen discussed pertinent literature on wound complications after DAA THA and techniques surgeons can use to prevent and manage them. According to the literature, the reported rates of superficial wound complications with DAA THA range from 1 percent to 12 percent, and the reported rates of periprosthetic joint infection (PJI) range from 1 percent to 3 percent. He noted several factors that could potentially lead to higher rates of superficial skin issues or wound complications, including inferior skin quality in the area of the approach, proximity to the groin crease and bacterial load contamination, and increased surgical times for surgeons who have more recently switched from different approaches.

The traditional longitudinal incision “is a very functional approach, but it does have some downsides,” Dr. Frandsen said. He noted that the longitudinal incision crosses Langer’s lines, with the proximal extent of the incision often being at the groin crease and sometimes crossing the groin crease. This can lead to complications with wound healing, particularly in patients with obesity whose incision may lie beneath the pannus.

DAA THA with a bikini incision, however, may help mitigate wound complications. The bikini incision is aligned parallel to flexion lines, and though it addresses some issues of the longitudinal incision, it’s not as extensible for femoral concerns intraoperatively and can lead to increased lateral femoral cutaneous nerve problems.

Dr. Frandsen also highlighted several strategies for wound complication mitigation in the postoperative period, focusing on the role of surgical dressings and advantages of negative pressure therapy. “One of the big benefits of negative pressure therapy is that it decreases wound tension,” he said. In addition to decreased wound tension, Dr. Frandsen noted the additional benefit of increased wound perfusion.

Femoral implant optimization and stem design
Dr. Frandsen was followed by Dr. Gorab, who told attendees, “I think when you’re a surgeon learning the anterior approach, the femur is the most intimidating part of the procedure.” He offered several “tips and tricks” on preventing femoral complications.

Dr. Gorab highlighted the use of a dedicated surgical table, noting its benefits in improving exposure to the femur and minimizing the need for additional assistants. “My assistant stands below me and pushes the distal aspect of the femur at the knee medially, which actually translates the proximal axis of the femur lateral. And even in large patients, it makes a tremendous difference,” Dr. Gorab said, stressing the importance of the assistant’s role.

He then outlined the process of femoral canal preparation and broaching techniques, starting with using a box osteotome to enter the canal and placing it in cancellous bone. He cautioned attendees to avoid cortical bone, stating, “I think that puts you at risk of knocking off the greater trochanter.”

Dr. Gorab touched on several crucial features of stem design, such as meta-physeal fill, implant length, shoulder relief, and the use of porous textured coatings for enhanced fixation. “Being too short might put you at risk of drifting into varus with the stem over time, but the right length makes access easier and simpler with distal support,” he said. He also advocated for triple taper stem and collar usage, citing several studies that showed lower fracture risk and revision rates and increased implant stability.

LFCN and femoral nerve complications
As the final panelist of the session, Dr. Taunton drew attention to the lateral femoral cutaneous nerve (LFCN) and femoral nerve (FN). DAA THA is associated with a high incidence of LFCN injury, with one study reporting a neuropraxia rate of 81 percent.

“What’s important for us to realize is that [the LFCN] does have a variable anatomy,” Dr. Taunton said. The LFCN varies in how it branches in the proximal thigh. Dr. Taunton delineated the three branching types: sartorius, posterior, and fan. According to a study by Thaler et al, 70 percent of the LFCNs they examined were sartorius-type branching (branches are more anterior), 14 percent were posterior-type branching, and 16 percent were fan-type branching (three to four major branches of equal thickness).

Understanding the patient’s anatomical distribution of LFCN branches is important in selecting the type of incision that will minimize nerve injury risk, as “we can control one but not the other,” Dr. Taunton said. He noted that the lowest risk of injury involves a laterally biased longitudinal incision performed in a patient with the sartorius-type nerve.

The overall incidence of FN injury across all THA approaches is low; however, studies have reported increased rates in DAA THA. Among the risk factors for FN injury that the surgeon can control, “Retractors are probably the biggest issue with femoral nerve injury,” Dr. Taunton said. He highlighted a 2019 study in the Journal of the AAOS^® that outlined three possible positions of an anterior retractor: over the anterior acetabular wall in line with the femoral neck (12 o’clock, middle position), 10 o’clock (superior relative to middle position), and 2 o’clock (inferior relative to middle position). “Placing the anterior retractor at the 12 o’clock position or higher is safe for the nerve, and make sure the retractors are on bone and relax them when not in active use,” he said.

Management of LFCN injuries can include massage and topical medications (e.g., lidocaine, nonsteroidal creams), whereas gait aids and training can be utilized for FN injuries. Should surgical management (e.g., late neurolysis, decompression) be necessary, “Calling a peripheral nerve specialist or a nerve surgeon to help is going to lead to better outcomes rather than coming back in a few days for repair,” he said.

To close the session, Dr. Taunton emphasized the importance of preoperative discussion with the patient on potential risks associated with the procedure.

“Your patient understanding that they’re going to have some numbness when they put their hand in their pocket can really lower any kind of anxiety if they’re to feel that in the first few weeks after surgery,” he said. “Remember to always discuss the risk of nerve injury in hip arthroplasty.”

Cailin Conner is the associate editor of AAOS Now.

References

1. Crawford DA, Rutledge-Jukes H, Berend KR, et al: Does a triple-wedge, broach-only stem design reduce early postoperative fracture in anterior total hip arthroplasty? Surg Technol Int 2019;35:386-90.
2. Lamb JN, Baetz J, Messer-Hannemann P, et al: A calcar collar is protective against early periprosthetic femoral fracture around cementless femoral components in primary total hip arthroplasty: a registry study with biomechanical validation. Bone Joint J 2019;101-B(7):779-86.
3. Goulding K, Beaulé PE, Kim PR, et al: Incidence of lateral femoral cutaneous nerve neuropraxia after anterior approach hip arthroplasty. Clin Orthop Relat Res 2010;468(9):2397-404.
4. Thaler M, Dammerer D, Hechenberger F, et al: The anatomical course of the lateral femoral cutaneous nerve in relation to various skin incisions used for primary and revision total hip arthroplasty with the direct anterior approach. J Arthroplasty 2021;36(1):368-73.
5. Fleischman AN, Rothman RH, Parvizi J: Femoral nerve palsy following total hip arthroplasty: incidence and course of recovery. J Arthroplasty 2018;33(4):1194-9.
6. Sullivan CW, Banerjee S, Desai K, et al: Safe zones for anterior acetabular retractor placement in direct anterior total hip arthroplasty: a cadaveric study. J Am Acad Orthop Surg 2019;27(21):e969-76.