Findings
Initial scout imaging with arm in slight internal rotation shows a probable Hill Sachs deformity. CT images show a fracture of the anterior glenoid that extends directly through the area of prior fixation of an arthroscopic Bankart repair. On the MRI, marrow edema is seen at the site of the recent Hill Sachs deformity as well as anteriorly at the site of recent glenoid fracture. Fracturing of the anterior glenoid through the site of prior fixation of a Bankart repair is again seen.
Diagnosis: Postage Stamp Fracture
A known complication following arthroscopic Bankart repair. The thought is that the site of fixation acts as a stress riser. When subsequent trauma occurs a fracture occurs through the area of prior fixation causing a serrated edge that resembles a postage stamp. Most frequently seen in young men who participate in sports, as in this case. Cases may have associated bone resorption at the sites of fixation but not always. The number of prior fixation sites as well as other surgical parameters are still being investigated to help determine who is at greatest risk for this injury. The injury is important to recognize because although a revision arthroscopic repair may be attempted, frequently a coracoid transfer procedure becomes necessary.
References
Taylor Woolnough B.MSc., Ajay Shah B.Sc., Andrew J. Sheean M.D., Bryson P. Lesniak M.D., Ivan Wong M.D., F.R.C.S.C., Dip. Sport Medicine and Darren de SA M.D., F.R.C.S.C. “Postage Stamp” Fractures: A Systematic Review of Patient and Suture Anchor Profiles Causing Anterior Glenoid Rim Fractures After Bankart Repair. Arthroscopy: The Journal of Arthroscopic and Related Surgery, 2019-08-01, Volume 35, Issue 8, Pages 2501-2508.e2, Copyright © 2019 Arthroscopy Association of North America