Analysis of clinical, radiological, and functional outcomes of robotic-arm assisted total hip arthroplasty (Mako®) at Hospital Clínico San Carlos

Objective: To analyse the clinical, radiological, and functional outcomes of robotic-arm assisted total hip arthroplasty (RA-THA) with a mean follow-up of 2 years at Hospital Clínico San Carlos, Madrid. Materials and methods: A prospective descriptive study was conducted including patients who underwent RA-THA using the Mako system (Stryker) between October 2021 and March 2024. All procedures were performed by 4 dedicated hip surgeons, excluding each surgeon’s learning curve. Demographic, clinical, functional, and radiological parameters were analysed. Mean follow-up exceeded 24 months. Results: A total of 226 patients were included (52% male, 48% female), with a mean age of 64.9 ± 12.9 years. Mean follow-up was 27.1 (range 12–36) months. Preoperative diagnoses were primary hip osteoarthritis in 88.5%, developmental dysplasia in 5.8%, avascular necrosis in 3.1%, post-traumatic osteoarthritis in 1.8%, and subcapital fracture nonunion in 0.4%. Mean operative time was 87.9 ± 23.4 minutes. Intraoperative complications included 11 technical events related to marker loss (4.86%), 6 greater trochanter fractures (2.6%), and 2 calcar fractures (0.8%). Mean acetabular component positioning was 43.1 ± 3.4° of inclination and 14.2 ± 3.8° of anteversion. Native femoral offset was preserved, with a mean difference of 1.8 ± 4.5 mm. Planned limb-length discrepancy accuracy was 90% within ±5 mm. Modified Harris Hip Score (mHHS) improved from a preoperative mean of 51.7 to 87.9 at 1 year ( p < 0.001). During follow-up, 5 neurological complications were recorded, 5 postoperative greater trochanter fractures, and 5 infections (2.2%), all successfully treated. 1 traumatic dislocation (0.4%) occurred without revision surgery. Conclusions: Robotic-arm assisted THA achieves high accuracy and precision in implant positioning and limb-length restoration, with a low dislocation rate. Operative time, complication rates, and short- to mid-term functional outcomes fall within the ranges previously reported in the literature for conventional techniques. Long-term studies are required to determine the impact of robotic assistance on implant survivorship.