Pre-clinical evaluation of a smartphone-assisted navigation system for surgical pin positioning in total knee arthroplasty

This is the authors' abstract. We don't add key points for this paper.

Total knee arthroplasty (TKA) success is highly dependent on accurate implant alignment, however, 80% of procedures globally are performed manually. Manual procedures have higher alignment errors compared to robotic platforms and patient-specific instrumentation, yet these have limitations of high cost and intraoperative inflexibility, respectively. This study aimed to evaluate the intraoperative pin positioning accuracy and flexibility of a smartphone-assisted navigation system using CT-derived surgical plans. Three participants used the navigation system to perform 108 guide pin insertions (54 femoral, 54 tibial) on surrogate bone models based on CT-derived surgical plans. Testing included both default mechanical axis targets (0°) and user-selected navigated targets ranging from -3° to 3°. Accuracy was assessed by comparing achieved pin trajectories with the preoperative surgical plan. Median absolute angular deviations achieved ranged from 0.9° to 1.6° across all component-plane combinations, with an overall median deviation of 1.3° (IQR 0.6-2.1°). The proportion of insertions within a predefined ±3° clinical accuracy threshold ranged from 83.3% to 100%, and all component-plane combinations demonstrated deviations significantly within this threshold (p < 0.00001). These findings support the technical feasibility of the smartphone-assisted navigation system for surgical pin positioning under controlled pre-clinical conditions. Further studies will evaluate the navigation system in cadaveric models with experienced orthopaedic surgeon participants.