An intra-operative device for parallel drilling and femoral landmark estimation during medial patellofemoral ligament reconstructive surgery

Background: The aim of this study was to design and test a device to guide medial patellofemoral reconstruction surgeries. Materials and methods: A three-dimensional (3D) printed, modular and cost-effective medial patellofemoral ligament (MPFL) reconstruction guide, Pat-Rig, was designed with parallel holes running in the medio-lateral direction. This device was manufactured using a commercial additive manufacturing facility, and bench tested using a custom-built test rig. CT scans of patella bones were reconstructed, and the device was tested on four 3D-printed patellas of various sizes. Results: The device was successful in guiding the surgical drill into the patella to drill parallel holes adhering to the current surgical requirements and specifications. The device was augmented with an innovative radiopaque scale which can allow the surgeon to accurately predict the landmarks to drill and measure the drill depth of the tunnels. Conclusion: There are no devices on the market that accurately predict the drill locations on the patella during MPFL reconstruction surgeries. The device, Pat-Rig, was found to overcome the current limitations of the MPFL surgeries and was able to provide satisfactory surgical guidance during the reconstruction. Level of evidence: Level 5