Successful Screw Placement in Scapula Cyst-Like Lesions in Six Horses

Introduction: Subchondral bone cysts in horses occur for several reasons including spontaneously occurring and induced trauma, as well as osteochondrosis. This case report describes six horses with chronic and varying degree of lameness, their diagnostic workup, as well as the surgical technique, used to treat subchondral scapula cystic lesions.

Materials and Methods: Between 2013 and present, 18 horses were diagnosed with scapula cyst-like lesions, one case presenting bilateral defects without lameness. A cranial approach in dorsal recumbency using lateral spinal marker needles was used in 5/6 cases. Erroneous orientation toward the joint can be prevented arthroscopically. One 5.5 screw in lag fashion is introduced. In two cases, a second 4.5-mm cortical screw was placed when placement of the first screw was deemed too peripheral.

Results: Five warmblood sport horses and one Andalusian are included in this study. No coexisting arthritic changes were found during surgery. The first case remained unsuccessful and was euthanized within 18 months. Cases 2 to 6 are back to soundness after reconvalescence of 4 to 12 months.

Discussion/Conclusion: The significance of scapula cysts is unclear and further workup was needed. Articular analgesia seems the easiest diagnosis justifying arthroscopic evaluation; however, results can be misleading if negative. A combination of other analgesic techniques and imaging for diagnosis-by-exclusion becomes necessary in these cases. Scintigraphy can be helpful in the presurgical diagnostic steps. This surgical technique for treatment of cyst-like lesions in the scapula was safe and successful in 5/6 cases.

Acknowledgment: There was no proprietary interest or funding provided for this project.