Arthroscopic assisted femoral tunnel drilling for the intra-articular anatomic cranial cruciate ligament reconstruction in dogs

Objective: To develop and test an arthroscopic aiming device for extra- to intra-articular femoral tunnel drilling emerging at the center of the femoral insertion of the cranial cruciate ligament (CrCL) in medium to large breed dogs. Material and methods: Hind limbs (n = 12) of six cadaveric dogs (>= 20 kg bodyweight). One hindlimb from each cadaver was randomly chosen. On a standard medio-lateral stifle radiograph the caudo-cranial position of the CrCL center was measured and transferred onto an adjustable aiming device. After arthroscopic debridement of the CrCL the aiming device was hooked behind the lateral condyle and a 2.4 mm guide pin was placed from extra- to intra-articular. The intra-articular position of the resulting bone tunnel was evaluated radiographically as well as compared to the anatomic CrCl center of the contralateral hindlimb using 3D renderings. Results: According to the postoperative radiographs all six drill tunnels were located at or near the CrCL center. The median absolute 3D error from the anatomical center of the CrCL was 0.6 mm (range: 0.2-0.9 mm). Conclusion: Precise anatomic placement of the femoral tunnel for intra-articular repair of the CrCL was achieved using an adjustable aiming device. Clinical relevance: The proposed technique will reduce femoral tunnel misplacement when performing intra-articular CrCL repair in dogs. In combination with the published technique for arthroscopic tibial tunnel drilling using a similar aiming device, the technical requirements for arthroscopic assisted tunnel positioning for anatomical graft replacement are available.