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Background In the last decade, the increase in the use of the direct anterior approach to the hip has contributed to the diffusion of the use of short stems in orthopedic surgery. The aim of the study is to verify the medium-term clinical and radiographic results of a cementless anatomic short stem in the anterior approach to the hip. We also want to verify whether the use of the standard operating room table or the leg positioner can affect the incidence of pre- and postoperative complications. Materials and methods All total hip arthroplasty patients with a 1-year minimum follow-up who were operated using the MiniMAX stem between January 2010 and December 2019 were included in this study. Clinical evaluation included the Harris Hip Score (HHS), Western Ontario and McMaster Universities Hip Outcome Assessment (WOMAC) Score, and Short Form-36 (SF-36) questionnaires. Bone resorption and remodeling, radiolucency, osteolysis, and cortical hypertrophy were analyzed in the postoperative radiograph and were related to the final follow-up radiographic results. Complications due to the use of the standard operating room table or the leg positioner were evaluated. Results A total of 227 patients (238 hips) were included in the study. Average age at time of surgery was 62 years (range 38–77 years). Mean follow-up time was 67.7 months (range 12–120 months). Kaplan–Meier survivorship analysis after 10 years revealed 98.2% survival rate with revision for loosening as endpoint. The mean preoperative and postoperative HHS were 38.35 and 94.2, respectively. The mean preoperative and postoperative WOMAC Scores were 82.4 and 16.8, respectively. SF-36 physical and mental scores averaged 36.8 and 42.4, respectively, before surgery and 72.4 and 76.2, respectively, at final follow-up. The radiographic change around the stem showed bone hypertrophy in 55 cases (23%) at zone 3. In total, 183 surgeries were performed via the direct anterior approach (DAA) on a standard operating room table, and 44 surgeries were performed on the AMIS mobile leg positioner. Comparison between the two patient groups did not reveal significant differences. Conclusion In conclusion, a short, anatomic, cementless femoral stem provided stable metaphyseal fixation in younger patients. Our clinical and radiographic results support the use of this short stem in the direct anterior approach. Level of evidence IV.

BACKGROUND The direct anterior approach for total hip arthroplasty (DAA-THA) is increasing in popularity due to some advantages such as less surgical trauma, minimal dissection of soft tissues, shorter rehabilitation times, faster return to daily activities, lower incidence of dislocation. On the other hand, the literature reports a high rate of intraoperative complications, with many different rates and complication types in the published papers. AIM To analyze our complications comparing results with the literature; to report measures that we have taken to reduce complications rate. METHODS All DAA-THA patients with one year minimum follow up who were operated at a single high-volume centre, between January 2010 and December 2019 were included in this retrospective study. All surgeries were performed using cementless short anatomical or straight stems and press fit cups. Patients’ follow-up was performed, at 6 wk, 3 mo, then annually post-surgery with clinical and radiological evaluation. Primary outcomes were stem revision for aseptic loosening and all-cause stem revision. Second outcome was intra-operative and post-operative complications identification. RESULTS A total of 394 patients underwent DDA-THA from January 2010 and December 2019, for a total of 412 hips; twelve patients lost to follow-up and one patient who died from causes not related to surgery were excluded from the study. The average age at the time of surgery was 61 years (range from 28 to 78 years). Mean follow-up time was 64.8 mo (range 12-120 mo). Seven stems were revised. One cortical perforation, one trochanteric and lateral cortical wall intraoperative fracture, one diaphyseal fracture, three clinically symptomatic early subsidence and one late aseptic loosening. We also observed 3 periprosthetic fractures B1 according to the Vancouver Classification. Other minor complications not requiring stem revision were 5 un-displaced fractures of the calcar region treated with preventive cerclage, one early infection, one case of late posterior dislocation, 18 case of asymptomatic stem subsidence, 6 cases of lateral cutaneous femoral nerve dysesthesia. CONCLUSION DAA is associated to good outcomes and lower incidence of dislocation. Complication rate can be reduced by mindful patient selection, thorough preoperative planning, sufficient learning curve and use of intraoperative imaging.

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