Robot-assisted total hip arthroplasty: optimal and rapid preservation of femoral offset and operated lower limb length.

Total hip arthroplasty (THA) improves quality of life in hip osteoarthritis. Robot-assisted (RA) surgery enhances implant placement precision, though its impact on outcomes remains debated. Its main limitation is the learning curve (LC), associated with longer operative times and potential complications. This study assessed the LC of the MAKO system using the LC-CUSUM (CUmulative SUM) test, focusing on femoral offset (FO), operated limb length (LL), surgical time, and implant positioning. We conducted a single-center retrospective study of 52 MAKO-assisted THAs performed between March 2023 and June 2024. Two trained surgeons operated using CT-based preoperative planning. Mean age was 64.7 years (39–85), mean body mass index (BMI) 27.5 kg/m² (13.9–40), with 56.9% females. Mean acetabular cup inclination was 40.4° (32°–49°) and anteversion 20.2° (10°–28°), with all implants within Lewinnek’s safe zone. Mean femoral stem version was 5° (–10° to 17°). FO was preserved (< 2 mm) in 79% and LL (< 5 mm) in 85% of cases. The LC was estimated at 22 cases for operative time stabilization, 5 for FO, and 15 for LL preservation. No revision was required; two infections occurred (4%). This is the first study identifying an LC for FO and LL preservation in MAKO-assisted THA. Rapid mastery improved implant accuracy, potentially enhancing recovery and reducing costs. The LC for operative time (about 20 cases) aligns with literature. MAKO-assisted THA shows a short LC and high precision. Further studies should assess functional and long-term outcomes.