Hip Dysplasia in a Context of Blue Rubber Bleb Nevus Syndrome, 5-years Follow-up after Hip Arthroplasty.

Abstract

Blue rubber bleb nevus syndrome (BRBNS) is a rare congenital vascular disorder that affects the venous system. Lesions are multiple and involved not only the skin and subcutaneous tissue but also muscles, joints and organs such as the gastrointestinal tract. At present, little is known regarding its potential orthopedic complications. We present a unique case of a patient with BRBNS displaying both intra-articular and extra-articular severe venous malformation (VM) of the hip. This extensive VM caused severe deformities in bone growth, mainly affecting the proximal femur, and impacted the muscular development of the gluteus medius and gluteus maximus. Its intra-articular extension, along with repeated secondary hemarthrosis, led to cartilaginous destruction. Consequently, the patient presented with significant coxa valga and developed acetabular dysplasia and subluxation of femoral head, during growth. In order to restore hip function and alleviate pain, the patient underwent a total hip arthroplasty (THA) at the age of 18. The dysplastic changes in the hip joint observed in this case are attributed to the deleterious effects of VMs and coxa valga on joint anatomy and biomechanics. VMs induce recurrent hemarthrosis, leading to cartilage destruction and hip instability. Additionally, coxa valga alters hip biomechanics, exacerbating joint instability and accelerating wear. Surgical intervention with THA aimed to restore joint stability and function, although challenges arose due to anatomical complexities and limited prosthetic options. This is the first reported case of hip dysplasia associated with BRBNS. This case shows the involvement of vascular malformation in the development of hip dysplasia leading to total hip arthroplasty. The surgical planning and technique must take the specificity of this pathology into account to get the best result possible for the patient. This case illustrates the importance of a multidisciplinary approach to treat patients with this specific syndrome and adds valuable information to the limited literature on orthopedic complications in BRBNS.