Feasibility Study of Fluoroscopy-Guided Lag Screw Fixation of Ununited Anconeal Processes

Introduction: Ununited anconeal processes (UAPs) occur from lack of union with the ulnar metaphysis, with purported etiologies varying from elbow incongruency, and trauma to genetics. Early identification and surgical correction are essential for mitigating the progression of osteoarthrosis. Due to the complexity of the elbow joint, fixation of fractures in this region can be challenging, although a recent study supported the use of CT-guided lag screw placement for UAPs. Conversely, we hypothesized that fluoroscopy-guided lag screw fixation would ensure accurate apposition and alignment while minimizing surgical time and potential contamination.

Materials and Methods: Three thoracic limbs from different canine cadavers weighing 20 to 25 kg were obtained. The anconeal process in each elbow was transected using a sagittal saw to emulate a UAP. Preoperative imaging (radiographs) was performed. Using fluoroscopy, Arthrex cannulated screws were placed in lag screw fashion caudocranially. Postoperative imaging (radiographs and CT scans) was then obtained.

Results: In two out of three elbows, CT revealed accurate alignment and apposition of the anconeal process fragment with adequate screw engagement. In one elbow, the screw failed to engage the trans cortex as it exited the anconeal process fragment medially, although there was adequate apposition.

Discussion/Conclusion: This pilot study found that fluoroscopy-guided cannulated lag screw placement was a feasible technique for surgical treatment of UAP. However surgical time would be dependent on the surgeon’s experience. This technique minimizes the risks of breaking asepsis outside the operating theatre. However, further studies inculcating the use of this technique in live patients would be beneficial.

Acknowledgment

None.

 

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Artikel online veröffentlicht:
15. Juli 2025