Bilateral Protrusio Acetabuli in an Elderly Female Patient: The Plain Radiographic Features and a Case Report

Protrusion acetabuli is the medial protrusion of the acetabulum in to the pelvic cavity, also known as arthrokatadysis, more common in females and classified etiologically as primary (idiopathic) and secondary forms. This is a 66-year-old female patient that presented for a plain radiograph of the pelvis and hip joints from a peripheral healthcare center on account of pain and inability to stand and move her waist and hips bilaterally, reduced movement of the legs and pain in the knees for more than three-year duration of onset. The plain radiograph of the pelvis and both hip joints demonstrate reduced density of the demonstrated bones, medial protrusion of the medial wall of the acetabulum in to the pelvic cavity bilaterally (distance between the imaginary Kohler’s line and medial acetabular wall is about 22mm bilaterally; Degree: III), obliteration of the hip joints bilaterally, thickening and sclerosis of the acetabular walls and other articular margins, subarticular cysts on the femur, acetabulum and pelvic bones. The patient had no coexisting condition like rheumatoid arthritis, Marfan’s syndrome and psoriatic arthritis. A diagnosis of bilateral idiopathic protrusio acetabuli was made. The patient was advised on bilateral total hip arthroplasty to improve the symptoms. We report a case of bilateral idiopathic protrusion acetabuli in an elderly female patient in order to describe the features of this condition radiographically.