Glenoid component lucencies are associated with poorer patient-reported outcomes following anatomic shoulder arthroplasty

Abstract

Background: High rates of radiographic glenoid loosening following anatomic total shoulder arthroplasty (TSA) are documented at midterm follow-up. Small studies remain conflicted on the impact of lucent lines on clinical outcomes. This study assesses the impact of radiolucent lines on function and patient-reported outcomes (PROs) following TSA.

Methods: We retrospectively evaluated 492 primary TSAs performed between February 2005 and April 2016. Radiographs were evaluated for glenoid loosening according to the Lazarus grade at a mean of 5.3 years (range, 2-12 years). Clinical outcome measures included range of motion and American Shoulder and Elbow Surgeons, Constant, University of California-Los Angeles, Simple Shoulder Test, and Shoulder Pain and Disability Index scores. Outcomes were compared between patients with and patients without glenoid lucent lines and in relation to lucency grade.

Results: At most recent follow-up, 308 glenoids (63%) showed no radiolucent lines (group 0) and 184 demonstrated peri-glenoid lucencies (group 1). The groups were similar regarding age, sex, body mass index, comorbidities, and prior surgery. At follow-up, group 1 demonstrated significantly lower improvements in forward elevation (P = .02) and all PROs (P ≤ .005). Subgroup analysis by radiolucency grade showed that forward elevation diminished with increasing radiolucent score and exceeded the minimal clinically important difference (MCID) above grade 2 lucencies. A similar decline in PROs was observed with increasing lucency grade. These differences did not exceed the MCID below grade 5 lucencies.

Discussion: Peri-implant glenoid lucencies following TSA are associated with lower forward elevation and PROs. Lucencies above grade 2 are associated with clinically important losses in overhead motion. However, differences below the MCID are maintained for PROs below grade 5 glenoid lucencies.

Keywords: Failure; glenoid loosening; loosening; outcomes; patient-reported outcomes; shoulder arthroplasty.