Abstract:

Complications following total hip arthroplasty (THA), such as dislocation, component loosening and wear, continue to be common indications for revision surgery. Multiple studies have attributed some of these problems to poor acetabular cup alignment and placement outside of the purported radiographic safe zone. In addition, it has been shown that conventional manually performed acetabular cup placement may not lead to optimal alignment, regardless of surgical experience. Additionally, incorrect leg length and offset can lead to dissatisfaction and instability. Therefore, robotic-arm assisted surgery has been introduced to improve accuracy of cup placement and leg length, and to offset with the aim of reducing the risk of hip instability and improving satisfaction after primary THA. Our aim was to prospectively review the use of robotic-arm assisted surgery in 224 patients and to assess whether the pre-operatively determined radiographic targets were achieved post-operatively and the proportion of acetabular cups outside of the safe zone. Pre-determined anteversion and inclination were 15 and 40 degrees, respectively. Our results have shown that the use of robotic-arm assisted surgery resulted in a post-operative mean inclination of 40 degrees (range, 34 to 51 degrees) and a mean anteversion of 16 degrees (range, 9 to 25 degrees). Ninety-nine percent of the patients remained within the pre-designated safe zone. Evidence has shown that robotic-arm assisted surgery may have improved accuracy in cup placement when compared to conventional surgery and possibly to computer-assisted surgery. When compared to the literature on robotic-arm assisted surgery, our results were comparable. We believe that this surgical technique may aid in reducing post-operative THA complications, such as aseptic loosening and dislocations, but further prospective studies are needed to evaluate clinical outcomes and long-term results.

Authors:

Randa K. Elmallah, MD, Research Fellow, Rubin Institute for Advanced Orthopedics, Baltimore, MD, Jeffrey J. Cherian, MD, Research Fellow, Rubin Institute for Advanced Orthopedics, Baltimore, MD, Julio J. Jauregui, MD, Research Fellow, Rubin Institute for Advanced Orthopedics, Baltimore, MD, David A. Padden, MD, Attending Physician, Holy Cross Med Group, Lighthouse Point, FL, Steven F. Harwin, MD, FACS, Chief of Adult Reconstructive Surgery, Mount Sinai Hospital, New York, NY, Michael A. Mont, MD, Rubin Institute for Advanced Orthopedics, Center for Joint Preservation and Replacement, Sinai Hospital of Baltimore, Baltimore, MD

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