Sequential Intra-articular Migration of Broken Circumferential Wire Fragments Following Patellar Surgery: A Case Report.

Cerclage compression wiring (CCW) is a standard surgical procedure for transverse patellar fractures. While hardware breakage is a common complication, the intra-articular migration of broken wires is rare. We report the case of a 79-year-old female with a four-part transverse patellar fracture (AO classification: 34C3) who underwent open reduction and internal fixation using CCW with additional circumferential wiring. Although the initial postoperative course was favorable, the circumferential wire fractured one year postoperatively, and patellar non-union was also confirmed at that time. Between 15 and 17 months postoperatively, further breakages and sequential migrations occurred one after another; these fragments migrated into the medial joint space and the posteromedial aspect of the fibular head, eventually leading to mechanical symptoms and limited range of motion. Surgical retrieval using a combined arthroscopic and open approach identified a linear cartilage lesion on the medial femoral condyle, likely representing mechanical abrasion caused by the migrated fragment. The deep placement of the circumferential wire potentially contributed to mechanical wear and subsequent fracture. Broken metal wires carry a risk of migration, and their presence within the joint space poses a risk of chondral injury. Improving surgical techniques, such as avoiding excessively deep hardware placement, and considering the optimal choice of fixation materials remain important challenges in preventing such hardware-related complications.