Accuracy of patient-specific, image derived instrumentation in glenoid prosthesis positioning: A randomised, controlled trial in reverse total shoulder arthroplasty (RTSA)

Over the past 10 years, rTSA has demonstrated excellent clinical outcomes and prosthesis longevity. As a result, the indications for rTSA have seen a huge expansion. Important to the overall success of rTSA and total shoulder arthroplasty (TSA) is appropriate location and orientation of the glenoid implant. Glenoid version and inclination needs to be corrected intra-operatively as malpositioning of the glenoid component has been demonstrated to predispose to prosthetic instability, loosening or even failure, necessitating revision surgery.

The development of 3D computed tomography (CT) images as part of pre-operative planning has been reported to improve the accuracy of glenoid placement. However, the surgeon’s ability to reproduce the 3D plan can be limited due to multiple factors including surgeon’s accuracy, complex glenoid deformities, and no reliable intra-operative landmarks. As a result, computer assisted technologies, including patient specific instrumentation (PSI), have been developed to improve the surgeon’s intra-operative accuracy of glenoid placement when compared to standard instrumentation (STDI) Therefore, this prospective randomised controlled trial (RCT) was designed to compare the accuracy of PSI to STDI groups in patients undergoing rTSA to add to the current evidence base.