Summary

Significant clinical gains after inlay total shoulder arthroplasty were observed at a mean follow-up of 8.5-year and reconfirmed our previous short-term results.

Abstract

Background

Current literature demonstrates improved patient reported outcomes (PROs) following inlay total shoulder arthroplasty (iTSA). However, long-term evidence regarding its use as a primary procedure for advanced shoulder osteoarthritis (OA) is limited. We previously demonstrated that iTSA resulted in significantly improved shoulder function, pain scores, and ROM at short-term follow-up. The purpose of this study was to evaluate if the long-term benefits are maintained. We hypothesized that long-term PROs demonstrate significant improvement over time.

Methods

The longitudinal cohort study was conducted in patients treated for advanced shoulder arthritis from 2011 to 2018. A minimum follow-up of 6 years identified patients with long-term results. Outcomes included the Western Ontario Osteoarthritis Score percentage (WOOS%), American Shoulder and Elbow Surgeon’s (ASES) score, the Visual Analog Scale for Pain (VAS-Pain), patient satisfaction, activities of daily living (ADLs), and shoulder range of motion (ROM). Walch and Samilson-Prieto classifications were used for preoperative radiographic assessment to define glenoid morphology and shoulder OA grade. Descriptive analyses and significance of improvements in functional outcomes and pain relief at last follow-up were assessed using Paired Samples T-tests and Levene’s Test for Equality of Variances. The effect of gender on outcome scores was assessed using independent t-tests.

Results

Our institutional database included 56 shoulders (26 bilateral) with a mean follow-up of 101 months ±19.4. The gender distribution was 50% for female and male patients with a mean age of 64.3 ±9.5 and mean BMI of 28.1 ±5.0. The glenoid Walch classification included A1 (32%), A2 (11%), B1 (4%), B2 (43%), B3 (2%), and C (8%). 93% had grade III OA, and 7% grade II. Consistent with our previous short-term results, all outcome scores significantly improved with a mean WOOS% from 28.3 ±16.9 to 82.6 ±22.0 (p < 0.001), ASES from 29.3 ±14.7 to 78.3 ±22.3 (p < 0.001), VAS-Pain from 7.4 ±1.9 to 0.8 ±1.7 (p < 0.001), and ADLs from 3.9 ±2.3 to 8.1 ±2.0 (p < 0.001). ROM significantly improved from 107.1° ±32.8 to 151.9° ±23.2 (p < 0.001) in forward elevation and 22.4° ±17.3 to 49.1° ±15.0 (p < 0.001) in external rotation. Mean patient satisfaction throughout the postoperative period was high with a score of 9.5 ±1.0 at last follow-up. Gender had no effect on outcome scores (p > 0.05).

Conclusions

Patients undergoing inlay total shoulder arthroplasty experienced significant improvements in pain, function, and shoulder range of motion and reported high levels of satisfaction at mean follow-up of 8.5 years. These long-term results support our previous short-term data and reconfirm the use of iTSA as an effective primary arthroplasty option for advanced shoulder osteoarthritis.