Surgeon Learning Curve for Minimally Invasive Hemiarthroplasty Using the Direct Anterior Approach for Treatment of Femoral Neck Fractures in Elderly Patients

Background: Femoral neck fractures (FNFs) are common injuries among the elderly and are a significant cause of morbidity and mortality. Hemiarthroplasty (HA) is the most suitable choice for elderly patients with multiple comorbidities and reduced functional demands. The direct anterior approach (DAA) to perform HA is widely used because, among other attractive features, it facilitates recovery of functional outcomes by limiting iatrogenic muscle damage. The learning curve for surgeons who perform minimally invasive HA using the DAA approach is unknown. The purpose of the study is to perform this determination. Methods: 850 patients (age: 82 ± 6 years) who had suffered FNFs were enrolled for the study between January 2017 and September 2022. The patients underwent minimally invasive hemiarthroplasty (using the anterior minimally invasive surgical (AMIS) technique) and DAA (AMIS + DAA). The patients were divided into three groups, one operated on by surgeons who have substantial experience in HA using DAA (Group A), another operated on by surgeons who have experience in adult hip arthroplasty (≥5 y) but had not specialized in using DAA (Group B), and surgeons who are being trained to perform adult hip arthroplasty (Group C). The metrics determined were duration of surgery, skin incision length, drop in hemoglobin level, length of hospital stay, complications experienced within 2 y of the procedure and the Harris Hip Score. For each of these metrics, the results were used to determine the learning curve for Groups B and C surgeons. Results: Using the learning curve profiles obtained, it was calculated that in order to achieve the competence of Group A surgeons, Group B and Group C surgeons need to perform 46 and 102 consecutive procedures, respectively. Conclusion: For an HA patient to achieve outcomes when treated for FNF using AMIS + DAA requires that the surgeon should have performed a large number of this procedure. In other words, the surgeon learning curve is modest for Group B surgeons but substantial for Group C surgeons.