Case ReportsCozen's Phenomenon After Repair of a Medial Collateral Ligament Periosteal Avulsion in a Pediatric Athlete A Case ReportHobson, Taylor E. MD1; Mortensen, Alexander J. MD1; Metz, Allan K. BS1; Aoki, Stephen K. MD1,a Author Information 1Department of Orthopaedics, University of Utah, Salt Lake City, Utah aE-mail address for S.K. Aoki:[email protected] Investigation performed at University of Utah Health, Salt Lake City, UT Author contributions: All authors reviewed the manuscript and contributed to the drafting, writing, and finalization of this case report. Disclosure:TheDisclosure of Potential Conflicts of Interestforms are provided with the online version of the article (https://links.lww.com/JBJSCC/B706). JBJS Case Connector: October-December 2021 - Volume 11 - Issue 4 - e21.00481 doi: 10.2106/JBJS.CC.21.00481 Buy Metrics Abstract Case: A 13-year-old boy sustained an acute, grade III medial collateral ligament (MCL) distal periosteal avulsion injury while playing noncontact football. Treatment consisted of diagnostic knee arthroscopy with open physeal-sparing MCL repair. At approximately 1-year follow-up, new development of genu valgum in the operative extremity was noted. After 8 months of nonoperative treatment with deformity progression, the patient underwent correction with proximal medial tibial hemiepiphysiodesis. Conclusion: Although Cozen's phenomenon commonly occurs after a proximal metaphyseal tibial fracture in children aged 2 to 7 years, it can occur as a rare complication of MCL injury/repair and remains a possible outcome in skeletally immature patients. Copyright © 2021 by The Journal of Bone and Joint Surgery, Incorporated
