Periprosthetic pathologic fracture following tibial Echinoccocosis: A case report.

INTRODUCTION: Hydatid disease in humans caused by the parasitic tapeworm Echinococcus granulosus has an osseous involvement of about 0.5%-2.5% of all cases in humans. The location of hydatid cysts in the tibia is seldom described in the medical literature, and its diagnosis and treatment is challenging. CASE REPORT: This paper presents a patient, with a long term, well tolerated, bilateral total knee arthroplasty (TKA), treated at our clinic, with a recent history of pain and oedema in her left upper leg. After achieving a, radiologically and histhopathologically, well documented, diagnosis of Echinoccocosis lesion in her left proximal tibia, a surgical intervention was planed, a wide resection of the cyst performed, and a specific anti-helmintic therapy was instituted. Four years later, she returns to our observation complaining of pain and unable to bear weight on her left knee, from which a pathologic fracture, adjacent to the tibial component, was diagnosed. After surgical debridement of the newly advanced hydatid cyst growth, the TKA was revised, and due to the tibial component failure and the femoral implant loosening, a semi-constrained total knee revision arthroplasty was executed. Functional outcome was excellent. CONCLUSION: Although challenges in treatment of musculoskeletal hydatid cysts (HC) lesions have been documented, data regarding the musculoskeletal HC lesions resembling tumor is scarce, and those resulting in a prosthetic failure have not been published. The authors intend to add data concerning the therapeutic approach to this entity.