Ununited anconeal process (UAP) fixation is challenging as targeting the center of the anconeal process (AP) with an implant leaves minimal margin for error. Retrograde drilling of the AP may improve accuracy by providing direct visualization of the cis-cortex of the small AP while increasing the area of the trans-cortical target of the much larger olecranon. The purpose of this canine cadaveric study was to evaluate a cranial arthroscopic portal approach (CAPA) to the supratrochlear foramen and to assess feasibility and accuracy of retrograde transarticular k-wire placement and cannulated drilling of the AP using CAPA. Cadavers (n = 8) were instrumented with a nanoscope through the supratrochlear foramen. The AP was identified and drilled using a 2.0 mm cannulated bit directed arthroscopically and with a C-guide. Experimental measures included arthroscopic AP identification, surgical time, and gross dissection to assess for critical structure damage and drill tunnel aperture location. CT was performed to evaluate tunnel trajectory. CAPA was performed in all specimens. Mean surgery time was 16.6 minutes. 7/8 tunnels had acceptable trajectories based on CT and gross dissection. One tunnel exited the lateral olecranon cortex, a C-guide was not used in this case. Major damage to critical structures was not observed in any specimen, however tunnels were directly adjacent to transcubital vessels and a musculocutaneous nerve branch. This technique was feasible, provided excellent visualization of the AP, and allowed accurate drilling when using a C-guide. Future studies are needed to fully describe the technique and evaluate clinical safety.
.jpg "Lindsey Schmeiser, DVM photo")