Patterns of loosening of the glenoid component

Abstract

The incidence of loosening of a cemented glenoid component in total shoulder arthroplasty, detected by means of radiolucent lines or positional shift of the component on true anteroposterior radiographs, has been reported to be between 0% and 44%. Radiolucent lines are, however, difficult to detect and to interpret because of the mobility of the shoulder girdle and the obliquity of the glenoid which hinder standardisation of radiographs. We examined radiolucencies around cemented glenoid components in 48 patients, with a mean follow-up of 5.3 years, and found progressive changes to be present predominantly at the inferior pole of the component. This may hold a clue for the mechanism of loosening of this implant. In five patients we performed an additional analysis of loosening of the glenoid component using digital roentgen stereophotogrammetric analysis (RSA). After three years, three of the five implants had loosened (migration 1.2 to 5.5 mm). In only one, with gross loosening, were the radiological signs consistent with the RSA findings. When traditional radiographs are used for assessment, the rate of early loosening is underestimated. We recommend that RSA be used for this.

Glenoid component insertion in total shoulder arthroplasty: Comparison of three techniques for drying the glenoid before cementation

“…Recent studies performed using radiostereometric analysis with tantalum markers imbedded in both the glenoid and polyethylene glenoid components have not demonstrated a correlation between early radiolucencies and subsequent component migration. 12,16 Other studies have shown some correlation between periprosthetic lucency and implant loosening. 1,3,8,19 The location of the radiolucencies may be an important prognostic indicator of future implant loosening.…”

Management of complications after revision shoulder arthroplasty

“…Radiolucent lines surrounding the glenoid component can indicate, but does not necessarily suggest, loosening. As defined by Nagels et al, radiolucency 2 mm or more or a shift in the component suggests radiologic loosening [43].…”

Principles of glenoid component design and strategies for managing glenoid bone loss in revision shoulder arthroplasty in the absence of infection and rotator cuff tear

“…It is worth noting that lucency surrounding the glenoid component does not necessarily imply glenoid loosening. Nagels et al 33 severe if they involve more than two-thirds. Classification is important because mild and moderate deficiencies are often suitable for component reimplantation with or without bone grafting of the glenoid whereas severe central or combined deficiencies often preclude implantation of new components.…”