Approach to Total Hip Arthroplasty in Gauchers Disease with Pre-Existing Spinopelvic Fusion.

Introduction: Avascular necrosis of femoral head secondary to rare metabolic Gaucher's disease (GD) can cause debilitating hip arthritis in young adults. It is an autosomal recessive disorder caused due to deficiency of lysosome enzyme glucocerebrosidase resulting in accumulation of its substrate in macrophages. The activated macrophages or the Gaucher cells causes hepatosplenomegaly, anemia, and thrombocytopenia. Extensive marrow involvement causes bony deformity, necrosis, and pathological fractures in non-neuropathic GD. Total hip replacement (THR) for young adult with secondary arthritis due to avascular necrosis (AVN) of femoral head in GD is complex and has high failure rate. As the abnormal cell infiltration involves both femoral head and the acetabulum. It becomes even more challenging, when associated spinopelvic fusion preexists. The altered biomechanics needs special attention to the anteversion of the cup placement and deciding the combined ante-version angle (CAVA). Case Presentation: We report a case of GD with avascular necrosis of the femoral head, who underwent spinopelvic fusion to address his osteonecrosis of lumbar vertebra. Previously unreported, here we will discuss the pre-operative radiological evaluation and other intra-operative challenges in the management of GD post-enzyme replacement therapy (ERT) with secondary hip arthritis by THR. Conclusion: Hip replacement surgery in patients with Gaucher disease related to secondary arthritis restores pain free mobility. Despite the young age of the patients with GD, prognosis remains better with THR after enzyme replacement therapy. The pre-operative planning, anticipation of complications in metabolically abnormal hip joints makes it a complex primary THR. However, in patients with the spinopelvic fusion placement of the cup, at the narrow range of angle of version with altered spinopelvic rhythm plays an important role in post-operative prosthetic hip stability and patient mobility.