Computed tomography to identify preoperative guidelines for internal fixation of the distal sesamoid bone in horses: an in vitro study.

The research presents the effectiveness of using computed tomography (CT) scans in determining the best way to insert screw implants into the distal sesamoid bone of horses using cadaveric paired equine forelimbs in an in vitro study.

Objective

The main aim of this research is to evaluate the reliability of computed tomography (CT) in identifying the optimal direction for the insertion of a cortical screw in the distal sesamoid bone of horses. Specifically, the researchers are interested in how well CT can be used to determine the longitudinal axis of this bone in intact (nonfractured) conditions.

Methodology

• The researchers used an in vitro study design, using cadaveric paired equine forelimbs (n=16).
• They assessed the insertion of a cortical screw in lag fashion along the longitudinal axis of intact (nonfractured) distal sesamoid bones.
• The study was divided into two experimental groups, one with larger (4.5 mm) and the other with smaller (3.5 mm) implants. Eight pairs of limbs were tested in each group.
• The direction of the distal sesamoid bone in each sample was determined using a CT scanner.
• The placement of the screws was checked by dissecting the specimen after the CT scan and comparing the results.
• The direction of the screw was considered satisfactory if it was entirely within the distal sesamoid bone without damaging the articular or flexural surfaces.

Results

• The study found that the proportion of the satisfactory direction of screws, following the criteria outlined, was 0.63 (5/8) for the 4.5 mm implants and 0.87 (7/8) for the 3.5 mm implants.

Conclusion

The researchers concluded that computed tomography is a valuable tool for identifying anatomical landmarks helpful for the successful insertion of 3.5 mm cortical screws in the distal sesamoid bones of horses. However, the study also suggests that further research might be necessary due to the less satisfactory results obtained with the larger, 4.5 mm screws.