Abstract
The robotic-assisted system (ROBODOC) is the first active robot that was designed to reduce potential human errors in performing cementless total hip arthroplasty (THA). We have reported minimum five years follow-up clinical results. However, to our knowledge, there have been no longer follow-up reports. The purpose of this study was to prospectively compare the minimum ten years follow-up results of robotic-assisted and hand-rasping stem implantation techniques.
Between 2000 and 2002, we performed 146 THA on 130 patients who were undergoing primary THA. Robot assisted primary THA was performed on 75 hips and a hand-rasping technique was used on 71 hips. Among them, 112 hips (53 hips in the robotic milling group and 59 hips in the hand-rasping group) were followed more than 10 years. Follow-up periods ranged from 120–152 months (average 135). Preoperatively, we plan the position and the size of the stem three-dimensionally for both groups. At the operation, posterolateral approach was used. We evaluated survivorship and compared clinical results.
At the final follow-up, no stem was revised in either group. Plain radiographs showed bone ingrowth fixation for all the stems of both groups. There were no signs of mechanical loosening in any implant. Preoperatively, there were no significant differences in the Japanese Orthopedic Association (JOA) hip scores between the two groups. Ten years postoperatively, it was significantly better in the robotic milling group (98 points and 96 points, respectively) (Mann-Whitney U-test; p<0.05). The main difference was observed in the category of range of motion (19 points and 18 points, respectively) (p=0.01).
In the previous study, we have reported that the JOA hip score was significantly better in the robotic milling group up to three years postoperatively. In the present study, we found that it was still significantly better at ten years postoperatively. In conclusion, robotic milling THA was associated with better clinical scores until ten years postoperatively.
