Fluoroscopy-based robotic assistance for total hip arthroplasty improves acetabular cup placement accuracy for obese patients compared to the manual, fluoroscopic- assisted technique
Affiliations: [a] Department of Orthopaedic Surgery, Orthopaedic and Rheumatologic Institute, Cleveland Clinic Foundation, Cleveland, OH, USA | [b] Chefarzt Zentrum für Orthopädie und Unfallchirurgie, HELIOS Kliniken Berlin-Buch, Berlin, Germany | [c] Department of Medicine for Orthopaedics and Motor Organs, Juntendo University Graduate School of Medicine, Tokyo, Japan | [d] Department of Orthopaedics, Faculty of Medicine, Juntendo University, Tokyo, Japan
Abstract: BACKGROUND: Patient obesity is a risk factor for poor acetabular cup positioning in total hip arthroplasty (THA). OBJECTIVE: To assess the impact of using a novel, fluoroscopy-based robotic THA system on acetabular cup placement in obese versus non-obese patients. METHODS: A review of 105 consecutive manual unassisted (mTHA) (47 Obese/58 Non-obese) and 102 robotic-assisted (RA-THA) (50 Obese/52 Non-obese) primary, direct anterior approach THA procedures was conducted. All cases were performed by a single surgeon, for a pre-operative diagnosis of osteoarthritis, avascular necrosis, or rheumatoid arthritis. Obesity was defined as a Body Mass Index (BMI) ⩾ 30 kg/m2. Outcomes included acetabular cup inclination and anteversion, and the proportion of cups within the Lewinnek safe-zone. RESULTS: Obese patients in the mTHA cohort had larger cup inclination angles on average compared to non-obese patients (44.82∘± 6.51 vs. 41.39∘± 6.75; p= 0.009). Obese mTHA patients were less likely to have cup placement within the Lewinnek zone compared to non-obese mTHA patients (0.48 vs. 0.67; p= 0.027). Obesity had no effect on the accuracy of RA-THA. CONCLUSION: Obesity affects the placement of the acetabular component in manual THA. The novel, fluoroscopy-based robotic THA system in this study demonstrated accurate cup placement regardless of obesity status.
