Is There a Long-Term Benefit to use Patient-Specific Guides for Glenoid Implant Positioning in aTSA? A comparative study at minimum 10 years.

BACKGROUND: The efficacy of patient-specific guides (PSGs) in improving accuracy and reducing the number of outliers in glenoid implant positioning in anatomic total shoulder arthroplasty has been clearly shown. However, long-term clinical benefit in terms of outcomes, revision rates and patient satisfaction remains unproven. Our purpose was to compare the long-term clinical and radiographic outcomes of two aTSA groups, with or without the use of a PSG for glenoid implant positioning.

METHODS: A retrospective comparative study based on a prospective cohort was conducted including all patients with aTSA Tornier Perform Anatomic Glenoid (Stryker, Kalamazoo, MI) performed between January 2013 and May 2015 at a minimum 10 years of follow-up (FU). Patients were divided into two groups based on the use of a 3D preoperative planning and PSG (PSG Vs no-PSG group) generated by Glenosys (Imascap, Plouzané, France). Forty-seven patients (27 in the no-PSG and 20 in the PSG group) were included. The last-FU radiographic and clinical outcomes were evaluated.

RESULTS: One patient was revised to a reverse shoulder arthroplasty in each group (p>0.999) for glenoid loosening. There was no difference in terms of Visual Analogue Score (1±2 Vs 1±1 ;p=0.254), Subjective Shoulder Value (85±15 Vs. 87±14 ;p=0.592), the rate of satisfaction (4: 73%; 3: 23%; 2: 4% Vs 4: 79% ; 3: 16%; 2: 5% ;p= 0.856), active anterior elevation (153±21° Vs 163±11°; p=0.148), passive anterior elevation (155±20° Vs 167±9° ;p=0.1), active external rotation (54±18° Vs 56±8° ;p=0.809) active internal rotation (7±3 Vs 7±2 ;p= 0.706), and adjusted Constant Murley Score (118±21 Vs 123±14 ;p= 0.76). Furthermore, no significant difference in terms of Mole's mean score (5±7 ;p=0.686) and in the rate of component migration (19% Vs 20% ;p= 0.999) was observed.

CONCLUSION: PSG systems for glenoid implants in aTSA show no improvement (revision and function) over 10 years of FU compared to the non-PSG method, indicating that PSG systems may not be necessary. The true benefits may lie in other areas that have not yet been sufficiently explored deserving specific evaluation.