During a short period of time, surgical robots had been propagated for automated tunnel placement in anterior cruciate ligament (ACL) reconstruction. Clinical outcome data are currently unavailable. Between 2000 and 2003, 152 patients underwent ACL replacement with the assistance of the Computer Assisted Surgical Planning and Robotics system (CASPAR, OrtoMaquet, Germany) at our hospital. After minimal invasive pin placement in both the tibia and femur, computed tomography was used to register anatomical landmarks and to plan graft tunnel alignment. The robot was used to drill tibial and femoral tunnels in an outside-in fashion according to pre-operative planning. There was one procedure-specific Serious Adverse Event (i.e., an intraoperative transection of the posterior cruciate ligament). After IRB approval, all patients were invited for a follow-up examination. Data from 100 patients (35 women, 65 men, mean age 35 [SD 11] years, median follow-up 61 [range 42-77] months) form the basis of this report. Side-to-side differences in anterior laxity were measured with the KT-1000 arthrometer. Patient-centered outcomes included the Lysholm-Score, the lower extremity functional scale (LEFS), and the Short Form 36 (SF36). The mean KT-1000 side-to-side difference was 0.89 [95% confidence interval (CI) 0.52-1.26] mm. Eight and five patients had a positive Lachman and pivot shift test, respectively. The Lysholm-Score averaged 86 (95% CI 83-89) points. Excellent, good, fair, and poor outcomes were reported by 38, 32, 20, and 10 patients. The LEFS averaged 85 (95% CI 82-88) points. The mean SF36 Physical Component Score was 48.4 (95% CI 46.5-50.3), indicating residual deficits compared to the population norm. All tibial graft tunnels did not cross the Blumensaat line, but were placed slightly anterior to the optimal center of 42% reported in previous studies. Compared to literature data, robot-assisted ACL reconstruction with BTB grafts may lead to higher knee stability, but poorer functional outcomes. The immense additional efforts with the procedure did not pay off in a benefit to patients.

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