Acetabular loosening using an extended offset polyethylene liner

Abstract

The use of extended offset femoral components and acetabular liners helps restore preoperative offset during hip arthroplasty. We report a relatively high acetabular component aseptic loosening rate with the use of offset polyethylene liners. We reviewed 1919 primary and 346 revision total hip arthroplasties (THAs). A 7-mm offset acetabular liner was used in 120 of the primary and 100 of the revision THAs. The aseptic loosening rate in the primary THA group was 0.12% in the standard offset and 4.2% in the extended offset groups at a minimum of 2 years (mean, 3.6 years; range, 2-9 years) followup. The aseptic loosening rate in the revision group was 1.7% in the standard and 7% in the extended offset groups at a mean of 4 years (range, 2-9 years) followup. Although extended offset acetabular liners help restore hip offset, torsional force applied to the implant-bone interface may have a detrimental effect on fixation. We found a relatively high failure rate in our primary and revision acetabular components used with an offset liner.

Level of evidence: Level III, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence.

Fig. 1

This radiograph demonstrates a primary THA with a 7-mm extended offset polyethylene liner.

Fig. 2

This is a radiograph of the same hip arthroplasty with early loosening of the acetabular component.

Fig. 3

This graph demonstrates 6-year survivorship of all primary hip arthroplasties with any reoperation as the end point.

Fig. 4

This graph demonstrates 6-year survivorship of primary hip arthroplasties with acetabular revision for aseptic loosening as the end point. Hips with standard liners are indicated by the solid line, whereas hips with extended offset liners are indicated by the broken line.

Fig. 5

This graph demonstrates 6-year survivorship of all revision hip arthroplasties with any reoperation as the end point.

Fig. 6

This graph demonstrates 6-year survivorship of revision hip arthroplasties with acetabular rerevision for aseptic loosening as the end point. Hips with standard liners are indicated by the solid line, whereas hips with extended offset liners are indicated by the broken line.