Cause for revision differs between a short and standard length stem at 5 year follow-up

Abstract

BackgroundThe purpose of this study was to compare the 5 year radiographic and clinical outcomes of anatomic total shoulder arthroplasties (TSA) performed with either a standard length (SL) or short stem. The hypothesis was there would be no difference in radiographic or clinical outcomes based on stem length. MethodsA multicenter retrospective review was performed of primary TSAs performed with a press-fit humeral component. Fifty SL and 72 short stems were available for review, of which 43 SL and 60 short stems had minimum 5 year follow-up. Functional outcome was assessed according to range of motion (ROM), visual analog scale (VAS) American Shoulder and Elbow Surgeons (ASES), and Single Assessment Numeric Evaluation (SANE) scores. Radiographs were reviewed for signs of humeral component loosening and stress shielding. ResultsAt final follow-up there were no differences in ROM, or ASES or SANE scores between groups (P>.05). Postoperative VAS scores were lower in the SL compared to the short stems (0.8 vs. 1.6; P = .053). All-cause revision was similar between the SL and short stems (16% vs. 22.2%; P = .395). Among SL stems there were no revisions for humeral loosening and none were considered radiographically at risk. Six short stems were revised for loosening (8.3%; P =.036 vs. SL). An additional 5 short stems were considered to be radiographically at risk for loosening for a total revision or at risk rate of 15.3% (P = .003 vs. SL). ConclusionThere is no difference in functional outcome at mid-term follow-up of TSA based on stem length with a grit-blasted humeral component. Revision for loosening and radiographic risk for loosening may be higher with a short stem compared a standard length humeral stem placed with press-fit fixation using grit blasting. Level of evidenceLevel III; Retrospective Comparative Study.