Influence of a purpose‐built frame on the accuracy of computer‐assisted orthopedic surgery of equine extremities

Abstract

Objective: To determine the influence of a purpose-built frame on the accuracy of screw placement during computer-assisted orthopedic surgery (CAOS) of the equine extremity. Study design: Experimental cadaveric study. Sample population: Twenty-four paired equine cadaveric limbs obtained from seven horses. Methods: Three 4.5-mm cortex screws were inserted in lag technique in three different planes of orientation in the proximal phalanx (P1) by means of CAOS. In the study group (n = 12 limbs), the tracker was anchored on a purpose-built frame designed to stabilize the extremity. In the control group (n = 12 limbs), a conventional tracker array was used that was anchored directly on P1. The stability of both tracker arrays was assessed during the procedure by using fiducial markers. After screw placement, preoperative and postoperative computed tomographic images were assessed to measure surgical accuracy aberrations (SAA) between the planned and achieved screw position. Descriptive statistics and repeated-measures analysis of variance were performed to compare SAA measurements between the study and control group. Results: Both tracker arrays remained consistently stable in all specimens. Mean overall SAA of screw insertion were lower in the study group (0.7 mm; median, 0.5; range 0-3.4) than in the control group (1.2 mm; median, 0.9; range, 0-4.2 mm). Conclusion: The mean SAA achieved in cortex screw placement using CAOS lies within the range of approximately 1 mm. The use of a purpose-built frame avoided additional drilling of the target bone and improved surgical accuracy compared with the conventional tracker array. Clinical significance: The purpose-built frame described in this report can be used to facilitate CAOS in equine orthopedics without compromising surgical accuracy. 1 | INTRODUCTION Numerous indications in equine orthopedic surgery demand the highest possible precision in cortex screw placement, leaving little room for error. Preoperative and intraoperative three-dimensional (3D) image guidance help increase the accuracy of cortex screw placement and set new standards in precision. 1-6 In addition, aiming

Accessory carpal bone fracture repair by means of computer‐assisted orthopaedic surgery in a Warmblood stallion

“…Recently, the successful application of this surgical navigation system, developed for human surgery, has been reported on clinical cases for various equine orthopaedic surgical procedures (de Preux, Klopfenstein Bregger, et al., 2020). However, technical refinements for its application on equine cases are required prior to integration into routine clinical use (de Preux, Vidondo, et al., 2020). In CAOS, optical tracking systems rely on a patient tracker that is securely anchored to the relevant anatomical region and remains in an angle‐stable connection with the target bone, thus not changing its orientation in relation to this target bone.…”

“…Furthermore, in human orthopaedic surgery, the pins utilised for tracker fixation have reportedly contributed to complications such as injury of neurovascular structures, pin‐track infection, or pinhole fractures (Bonutti et al., 2008; Hoke et al., 2011; Jung et al., 2011; Li et al., 2008; Sikorski & Blythe, 2005). To overcome those drawbacks, a purpose‐built frame was developed for CAOS applications involving the distal extremities of horses and extending up to the level of the proximal metacarpal or metatarsal bones (de Preux, Vidondo, et al., 2020). The fibreglass cast utilised in this case report served the same purpose as the frame: it stabilised the carpus in extension and minimised significant movement of the antebrachiocarpal, middle carpal and carpometacarpal joints.…”

Use of Hausdorff Distance and Computer Modelling to Evaluate Virtual Surgical Plans with Three-Dimensional Printed Guides against Freehand Techniques for Navicular Bone Repair in Equine Orthopaedics

“…This is supported by other equine based CAOS studies using intraoperative CT guidance which also did not demonstrate 100% plan execution. 10 In the context of the present study, reasons for lack of 100% plan compliance likely resulted from the variation in goodness-of-fit of the PSG which can result from either a poor preoperative VSP, inconsistencies in print dimension and physical quality of the PSG itself, ability of the PSG guide to conform to the target tissue, deflection of the drill bit within the hoof as it engages the navicular bone or postprocessing irregularities which can occur with segmentation and modelling of bones; all of these factors may contribute to HD and angular aberrations in the 3D VSP approach. It would have been possible to evaluate the PSG goodness-of-fit with the hoof, but this was beyond the scope of this study.…”

“…8,9 In addition, the use of CT for surgical navigation has been shown to be highly accurate for the placement of screws in the distal phalanx of horses in computer-assisted orthopaedic surgery (CAOS). 10,11 While CT-based surgical navigation is considered the gold standard for the placement of screws in real time, there are several advantages to 3D printed guides generated from VSP when performing complex procedures such as corrective osteotomies, including development of customized cutting and reduction guides. 12,13 However, when using 3D guides, evaluation of final model accuracy can be challenging.…”

Fracture of the accessory carpal bone—conservative or surgical therapy?

“…Koch and colleagues developed an alternative to using pins in the bones by fixing the limb in a hard shell, which prevented movement and acted as a reference for the infrared camera. This improved technique allows increased surgical precision and has been used to successfully treat various orthopaedic problems in horses (De Preux et al, 2020a;De Preux et al, 2020b). De Preux et al (2022 used CAOS to insert two lag screws, a 4.5-mm and a 3.5-mm cortical screw, into the ACB of their patient.…”