Primary shoulder replacement using stemless inlay arthroplasty as a joint preservation alternative

Background: Stemmed shoulder arthroplasties are being performed at increasing rates with loosening and revisions on the rise. Stemless inlay arthroplasty may be an effective alternative. Our purpose is to report 5-year results of primary joint-preserving stemless inlay arthroplasty. Methods: Twenty patients (22 shoulders), mean age 60.41 (range, 43-80) years followed for an average of 68.14 (range, 24-98) months were evaluated prospectively using the Constant, visual analog scale (VAS) pain, Simple Shoulder Test (SST), range of motion, Short-Form (SF)-36 Physical Component score (PCS), and Mental Component score (MCS), and radiographs. The Student t-test was used to compare mean differences from preoperative to postoperative with significance set at P< 0 05 a priori. Results: Significant improvements were demonstrated: Constant (39.4-82 .05, P<0.001), VAS pain today (6.2-3.2, P<0.001), VAS pain (activity) (7.7-3.4, P<0.001), VAS stability (5.3-1.7, P<0.001), SST (3.8-7.5, P< 0.001), external rotation (33.7-47.04, P= 0.04), and internal rotation (Constant: 5.3-7.1, P= 0.008) SF-36 MCS (48-06-51.5, P=0.34), SF-36 PCS (37.4-42.6, P= 0.065), VAS pain (rest) (3.5-2.7, P = 0.4), active (118.4-124.3, P= 0.63) and passive forward elevation (131.3-142.3, P=0.25) improved but not significantly. Follow-up radiographs showed no periprosthetic radiolucency, subsidence, or progression of disease. No revisions were attributed to failure of the implant. Conclusions: Stemless inlay arthroplasty is safe and effective, showing significant pain and functional improvements at an average of 5 yr. Inherent joint preservation lends itself well as a primary alternative for symptomatic glenohumeral degeneration.