Pseudotumor associated with cemented bipolar hemiarthroplasty: an unusual presentation as a granulomatous thigh mass

Abstract

Although polyethylene wear-induced osteolysis is a common complication of hip arthroplasty, extensile osteolysis developing into a large granulomatous thigh mass at a site distant from the joint is rare. We report a case of a thigh pseudotumor 25 years after cemented bipolar hemiarthroplasty, in which x-rays revealed a radiolucent line around the stem at the proximal site only, not at the diaphysis of the femur. We initially suspected a real tumor because it had a unique appearance, as if the mass resorbed the posterior cortex of the femur, and it was located at a site distant from the proximal osteolytic lesions. We clearly showed the existence of a connection between the thigh mass and the joint space by performing intra-articular injection of contrast medium with continuous pressure. It seemed that polyethylene wear particles were transported distally along the stem-cement interface by fluid pressure, and an osteolytic reaction against polyethylene wear particles had occurred at the posterior middle third of the stem where the cement mantle was nonuniform and polyethylene particles first came into contact with the bone. Our findings suggest that nonuniform cemented prosthesis with osteolysis, even if it is low grade in a limited area, carries the risk of extensile osteolysis with asymptomatic development of an extra-articular granulomatous mass.

Massive pseudotumor of unknown etiology in a cemented metal-on-polyethylene total hip arthroplasty: a case report

“…Polyethylene debris can also be a source of foreign body reactions leading to granulomatous based pseudotumors ( 4 , 10 - 12 ). There are several cases of pelvic masses and osteolysis associated with THAs secondary to polyethylene debris ( 13 , 14 ).…”

Two Cases of Polyethylene Granuloma After Distal Femoral Endoprosthesis With All-Polyethylene Tibia

“…In some cases, foreign body reaction to polyethylene can also lead to the formation of a tumor-like softtissue mass, termed polyethylene granuloma or pseudotumor, often detectable by conventional imaging modalities such as plain radiograph and CT [6][7][8][9][10]. This is particularly notable in total hip arthroplasty where the formation of polyethylene granuloma on the femoral side has been more commonly reported [9][10][11][12][13][14]. Histologically, polyethylene granuloma is characterized by histiocyte infiltration and evidence of polyethylene particulates engulfed by macrophages, circumscribed by multinucleated foreign body giant cells [8][9][10]15].…”

Compression of the Femoral Vessels by a Pseudotumor after Metal-on-Metal Total Hip Arthroplasty

“…There have been several reports of patients in whom the femoral vessels became compressed by a large pseudotumor and whose presentation was similar to that of our patient [ 12 , 13 ]. Basically, progression of osteolysis or a pseudotumor associated with a hip prosthesis tends to extend around the iliopsoas tendon or external rotator muscles because of the pressure gradient in the effective joint space; that is, a pseudocapsule generated after THA has some weak areas where herniation or extrusion into the joint space is more likely to occur [ 14 ]. Patients with a mass extending anteriorly along the iliopsoas tendon may be at increased risk of compression of the femoral vasculature.…”