34th Annual Scientific Meeting proceedings

Objectives:

Veterinary literature has limited studies on the ability of plain radiography to detect intra-articular implant penetration. This study aimed to determine if intra-articular implant penetration in the canine stifle could be detected with plain radiography when implants were placed at predetermined distances and directions. The null hypothesis was that a 2mm intra-articular implant in the stifle joint cannot be detected by plain radiography.

Methods:

A 3.5mm stainless steel cortical screw was placed in the proximomedial tibia and directed toward either the medial or lateral tibial condyle to a predetermined distance from the joint surface: -2mm, 0mm, and 2mm. Joint examination confirmed screw penetration. Standard radiographic views were obtained. Radiographs were evaluated via an online survey by registered small animal surgery and radiology specialists, residents, and registrars.

Results:

The proportion of implants that were classified as penetrating the joint surface varied with implant distance (p<0.001) and ranged from 16.1% (-2mm) to 97.2% (2mm). Overall, 32.4% (594) of radiographs were incorrectly classified as penetrating the joint surface. Implants directed toward the lateral tibial condyle were misclassified more frequently than those directed medially (23.8% versus 8.3%).

Conclusions:

The authors rejected the null hypothesis, concluding that a 2mm intra-articular implant placed in canine cadaver stifle joints can be detected by plain radiography. Approximately 30% of non-penetrating implants were incorrectly identified as penetrating, particularly those directed laterally. This may suggest a higher proportion of implants being falsely interpreted as penetrating the joint surface in postoperative radiographs of the canine stifle.