Acetabular Bone Loss: Case Presentations

Case 1

A 39-year-old man had a right total hip arthroplasty (THA) in 1996 at the age of 26 for degenerative changes of the hip caused by osteomyelitis he had as a child. Pain developed over the course of a week and was localized to the right buttock. He had no history of trauma. There were no constitutional symptoms to suggest an underlying infection. Other than having bilateral osteomyelitis of the hip as a child and the eventual THA, his medical history was unremarkable.

Physical examination identified an incision from a previous posterior approach. He walked with a limp and required the assistance of a cane. Hip range of motion with internal and external rotation re-created the right buttock and groin pain. The right leg was approximately 2.5 cm shorter than the left. Results of his neurovascular examination were normal.

Radiographic examination revealed a noncemented, right THA with asymmetric positioning of the femoral head within the acetabular cup ( Fig. 42.1 ), which was consistent with polyethylene wear. The femoral stem was in slight varus, and there was evidence of osteolysis around the cup. At least one of the acetabular screws was broken. Dysplastic changes were seen within the left femoral head along with secondary, severe degenerative changes.

Case 2

A 72-year-old woman underwent a primary right THA in 1978, followed by multiple revisions. She was seen on a yearly basis because serial radiographs revealed excessive wear of the polyethylene insert, but there was no associated osteolysis, and she was not symptomatic. Eventually, the patient developed pain in the right groin. Radiographs ( Fig. 42.2 ) demonstrated severe, asymmetric polyethylene wear, with the femoral head articulating with the acetabular cup. Osteolysis was seen around the central and inferior portions of the acetabular cup. The patient also had an uncemented THA on the left with a minor column structural allograft.