Do preoperative radiographs help predict intraoperative challenges in revision surgery after previous shoulder hemiarthroplasty?

BACKGROUND: This study compares preoperative radiographic evaluation with intraoperative video and explant data in patients undergoing revision of a hemiarthroplasty. METHODS: From 2004 to 2017, 182 shoulder hemiarthroplasties underwent revision to reverse shoulder arthroplasty for symptomatic failure. Preoperative radiographs were evaluated for stem fixation, stability, and glenohumeral registry. Intraoperative videos (n = 48) were evaluated for humeral component stability and bone loss after humeral stem extraction. All explants (n = 83) were reviewed for humeral head wear patterns and extraction artifacts (EAs). RESULTS: A well-fixed stem was reliably identified on radiographs as well fixed (true-negative rate, 95%). Of cemented implants, 94% (97 of 103) were radiographically stable and 90% (18 of 20) were stable on intraoperative video. Significant proximal humeral bone loss was identified after cemented stem extraction in 83% of cases, and severe EAs were noted in 28% (14 of 50). Of uncemented implants, 95% (75 of 79) were radiographically stable and 96% (24 of 25) were operatively stable. Significant proximal humeral bone loss was identified after extraction in 36% of cases (9 of 25) (P = .001). Severe EAs were seen in 13% of explanted stems (3 of 23). Eccentrically worn humeral head explants were associated with eccentric glenohumeral registry in 84% of cases (P = .0075). CONCLUSION: Preoperative radiographs for revision of a failed hemiarthroplasty help identify well-fixed stems and predict humeral bone loss during extraction. Cemented stems will have more EAs and result in greater bone loss than uncemented stems. Glenohumeral registry can help to predict humeral head wear. Eccentric registry leads to eccentric humeral head wear in 84% of cases.

Improving preoperative planning of revision surgery after previous anatomic total shoulder arthroplasty.

BACKGROUND: The purpose of this study was to compare preoperative radiographic evaluation with intraoperative video and explant analysis in patients undergoing revision of a previous anatomic total shoulder arthroplasty (TSA). METHODS: We evaluated the preoperative radiographs of 165 revisions of failed TSAs for component loosening and glenohumeral registry (ie, the spatial relationship of the glenoid component and the prosthetic humeral head). Seventy-nine intraoperative videos were evaluated for component stability, rotator cuff (RC) integrity, synovitis, and glenoid bone loss. Eighty-seven explants were reviewed to assess wear patterns and presence of backside cement. RESULTS: Of 79 glenoid components, 47 were radiographically loose, but only 30 of 79 were loose intraoperatively. Thirty-two were radiographically fixed, but only 26 of 32 were fixed intraoperatively. If radiographically loose, 53% had severe glenoid bone loss. If radiographically fixed, 77% had mild to moderate bone loss (P = .008). Synovitis was associated with glenoid fixation: mild with a loose glenoid (6%) and severe with a fixed glenoid (30%, P = .012). Superior registry comprised 46%. RC deficiency was associated with posterior and anterior registry (88% and 79%, respectively). Explant examination revealed an eccentric wear pattern was predominant. CONCLUSION: Radiographic evaluation of glenoid loosening in patients undergoing revision of TSAs will often differ from intraoperative findings (40% false-positive rate and 17% false-negative rate). Assessment of glenohumeral registry can help anticipate RC deficiency, with posterior and anterior registry associated with RC deficiency. Patients with a loose glenoid are more likely to have severe synovitis and more severe glenoid bone deficiencies. Failed TSAs are more likely to have asymmetrical wear of the glenoid component, suggesting altered pathomechanics that may have led to failure.