Fibromyxoid pseudotumor of the ligamentum teres treated with fresh osteochondral allograft.

Intra-articular tumors and tumor-like conditions of the hip are rare. When they occur, they can interrupt normal articular congruency, leading to pain and joint dysfunction. If these conditions result in large osteochondral defects, they pose challenging reconstructive problems in young patients. We describe a case of a 29-year-old man who presented with a 2-year history of right hip pain. Advanced imaging demonstrated an expansile lesion in the region of his ligamentum teres (LT), eroding a significant portion of his femoral head and expanding the cotyloid fossa. He was treated with surgical hip dislocation, excision of the lesion, and femoral head reconstruction with fresh osteochondral (OC) allograft transplantation via press-fit technique. Histologic examination of the mass showed a benign fibromyxoid pseudotumor. Although non-neoplastic masses have been described in almost all organ systems, to our knowledge this is the first description of this entity affecting the native hip joint. It is only the second description of using press-fit OC allografting in the femoral head. This case adds to the body of literature defining symptomatic LT pathology that may benefit from surgical management. It underscores the need to study the ligament further, as the ability to diagnose and treat intra-articular hip pathology has improved with modern imaging and methods of open and arthroscopic hip surgery.