Prepatellar bursa mucosa: An unreported postoperative complication of patellar fracture

Background: Patellar fracture is a common injury caused by overstrain of the extensor mechanism or a direct trauma to the knee. The most common complications after patellar fracture are nonunion, infection, post-traumatic arthritis, joint fibrosis, symptomatic hardware, and extensor mechanism failure. These are attributed to the post-fracture flexion and extension movements, the primary damage to the articular cartilage, and the thin soft tissue coverage over the knee. To our knowledge, prepatellar bursa mucosa is an unreported postoperative complication of patellar fracture.

Methods: We describe a case of a 58-year-old woman with a left patellar fracture from a fall. Complete healing was achieved after in 2 months postoperatively using the improved Kirschner wire tension band and a cable grip system; however, at 7 months postoperatively, a prepatellar skin mass appeared. The patient reported prepatellar discomfort with no pain and influence of movement of the knee and daily life. One year postoperatively, we surgically removed the implants and mass. The pathological result showed bursa mucosa.

Results: The literature review shows that pain, secondary knee dysfunction, fracture nonunion, and malunion are postoperative complications of patellar fractures. However, prepatellar bursa mucosa have not been previously reported as a postoperative complication.

Conclusion: This case highlights the need for appropriate placement of the intraoperative implant in adults with patellar fractures.