Avoiding Glenoid Baseplate Fixation Failure by Altering Surgical Technique for Varying Bone Densities
Kyle Achors1, Miguel A Diaz2, Peter Simon2,3
1Department of Orthopaedics and Sports Medicine, University of South Florida Morsani College of Medicine, Tampa, Florida.
JB & JS Open Access
|September 21, 2022
Summary
Altering surgical techniques for reverse shoulder arthroplasty (RSA) significantly improves glenoid baseplate fixation in various bone densities. Preoperative imaging can guide the use of these improved techniques to prevent fixation failure.
Area of Science:
- Orthopedic Surgery
- Biomechanical Engineering
- Radiology
Background:
- Glenoid baseplate failure is a significant cause of revision and poor outcomes in reverse shoulder arthroplasty (RSA).
- Optimal time-zero fixation of the glenoid baseplate is crucial for successful RSA outcomes.
- Variations in bone density can compromise baseplate stability.
Purpose of the Study:
- To evaluate if modifications in surgical technique can enhance the initial fixation of the glenoid baseplate in RSA across different bone densities.
- To determine if preoperative radiographic assessment of glenoid sclerosis width can predict the need for these modified techniques.
Main Methods:
- A biomechanical analysis was conducted using bone-substitute blocks of varying densities to compare standard surgical techniques with two modified techniques (under-preparation [A1] and over-preparation [A2] of the central screw pilot hole).
- Torque-compression relationships were measured to assess fixation strength.
- A retrospective review of primary RSA cases (2007-2020) identified patients who underwent the modified techniques, matched with those who had the standard technique.
- Preoperative radiographs were compared between groups, and interrater reliability for glenoid sclerosis measurement was assessed.
Main Results:
- In low-density bone, the A1 technique increased average compressive force from 112 N (standard) to 300 N (p=0.01).
- In high-density bone, the standard technique led to failure, while the A2 technique achieved successful seating with 450 N average compressive force.
- A significant difference in glenoid sclerosis thickness was observed between experimental and control groups in the high-density cohort (p=0.0014).
- Interrater reliability for sclerosis measurement was high (0.69 for low-density, 0.92 for high-density).
Conclusions:
- Modified surgical techniques significantly improve glenoid baseplate compression and seating in both low- and high-density bone models.
- Preoperative radiographic identification of glenoid sclerosis can guide the selection of appropriate alternative surgical techniques.
- Implementing these techniques can enhance time-zero fixation and potentially reduce the incidence of baseplate failure in RSA.
