Visualization of postoperative anterior cruciate ligament reconstruction bone tunnels: Reliability of standard radiographs, CT scans, and 3D virtual reality images

Background and purpose: Non-anatomic bone tunnel placement is the most common cause of a failed ACL reconstruction. Accurate and reproducible methods to visualize and document bone tunnel placement are therefore important. We evaluated the reliability of standard radiographs, CT scans, and a 3-dimensional (3D) virtual reality (VR) approach in visualizing and measuring ACL reconstruction bone tunnel placement. Methods: 50 consecutive patients who underwent single-bundle ACL reconstructions were evaluated postoperatively by standard radiographs, CT scans, and 3D VR images. Tibial and femoral tunnel positions were measured by 2 observers using the traditional methods of Amis, Aglietti, Hoser, Stubli, and the method of Benereau for the VR approach. Results: The tunnel was visualized in 50-82% of the standard radiographs and in 100% of the CT scans and 3D VR images. Using the intraclass correlation coefficient (ICC), the inter- and intraobserver agreement was between 0.39 and 0.83 for the standard femoral and tibial radiographs. CT scans showed an ICC range of 0.49-0.76 for the inter- and intraobserver agreement. The agreement in 3D VR was almost perfect, with an ICC of 0.83 for the femur and 0.95 for the tibia. Interpretation: CT scans and 3D VR images are more reliable in assessing postoperative bone tunnel placement following ACL reconstruction than standard radiographs. Copyright

Comparative study of knee anterior cruciate ligament reconstruction with or without Xuoroscopic assistance : a prospective study of 73 cases

Introduction Correct placement of both tibial and femoral tunnels is one of the main factors for a favorable clinical outcome after anterior cruciate ligament (ACL) reconstruction. We used an original system of computer assisted surgery (CAS). The system, based on Xuoroscopic guidance combined with special graphical software of image analyzing, showed to the surgeon, before drilling, the recommended placement of tibial and femoral tunnel centers. We compared the Wrst anatomical and clinical results of this procedure to the usual one single incision technique. Materials and methods We conducted a prospective study on 73 patients; 37 patients were operated on with CAS and 36 without CAS, by the same senior surgeon. The mean age was 27 years for both groups. Every patient was reviewed at an average of 2.2 years (range 1–4.5) by an independent observer, using IKDC scoring system, KT-1000, and passive stress radiographs. Results Time between ACL rupture and reconstruction averaged 30 months for both groups. CAS needed 9.3 min extra surgery time. Clinical evaluation was graded from A to C as per the IKDC scoring system: 67.6% A, 29.7% B, 2.7% C with CAS; and 60% A, 37.1% B, 2.9% C without CAS. IKDC subjective knee evaluation score averaged 89.7 with CAS and 89.5 without CAS. Pre operative KT-1000 maxi manual diVerential laxity averaged 7. At revision time, all the patients after CAS had a diVerential laxity less than 2 and 97.7% without CAS. Stress X-rays diVerential laxity averaged 2.4 mm with CAS and 3 mm without CAS. The area of dispersion of the tunnels’ center was smaller on the femoral side using the CAS method. There was no statistically signiWcant diVerence between both groups using IKDC score, KT-1000 and passive stress radiographs. Conclusions The CAS method provided a more accurate and reproducible tunnels placement without clinical signiWcant eVect. Introduction Correct placement of both tibial and femoral tunnels is one of the main factors for a favorable clinical outcome after anterior cruciate ligament (ACL) reconstruction. We used an original system of computer assisted surgery (CAS). The system, based on Xuoroscopic guidance combined with special graphical software of image analyzing, showed to the surgeon, before drilling, the recommended placement of tibial and femoral tunnel centers. We compared the Wrst anatomical and clinical results of this procedure to the usual one single incision technique. Materials and methods We conducted a prospective study on 73 patients; 37 patients were operated on with CAS and 36 without CAS, by the same senior surgeon. The mean age was 27 years for both groups. Every patient was reviewed at an average of 2.2 years (range 1–4.5) by an independent observer, using IKDC scoring system, KT-1000, and passive stress radiographs. Results Time between ACL rupture and reconstruction averaged 30 months for both groups. CAS needed 9.3 min extra surgery time. Clinical evaluation was graded from A to C as per the IKDC scoring system: 67.6% A, 29.7% B, 2.7% C with CAS; and 60% A, 37.1% B, 2.9% C without CAS. IKDC subjective knee evaluation score averaged 89.7 with CAS and 89.5 without CAS. Pre operative KT-1000 maxi manual diVerential laxity averaged 7. At revision time, all the patients after CAS had a diVerential laxity less than 2 and 97.7% without CAS. Stress X-rays diVerential laxity averaged 2.4 mm with CAS and 3 mm without CAS. The area of dispersion of the tunnels’ center was smaller on the femoral side using the CAS method. There was no statistically signiWcant diVerence between both groups using IKDC score, KT-1000 and passive stress radiographs. Conclusions The CAS method provided a more accurate and reproducible tunnels placement without clinical signiWcant eVect