3D-Printable Knee Arthrometer: Development and Validation

Introduction The anterior cruciate ligament is the most commonly injured ligament in the knee. Its injury is often evaluated with orthopedic tests during physical examination, but this turns out to be a subjective assessment. A knee arthrometer is a mechanical device developed in the 1970s to improve the diagnostic accuracy of anterior cruciate ligament injury. However, due to the high cost and low availability of the devices, they are rarely used in clinical practice and training. In this scenario, the objective of this study was to develop and validate a knee arthrometer to be fabricated by additive manufacturing (3D printing), thus creating a device that is easily accessible to all. Methods This experimental cross-sectional study involved the Orthopedic Skills Laboratory, Department of Surgery, at the Federal University of Paraná and 3D Printing Laboratory of the Professor Leide Parolin Marinoni Simulation Center of Parana Clinical Hospital, in partnership with the Engineering Department at the Federal University of Technology - Paraná, Brazil. Additionally, face validity was conducted at the Workers' Hospital and Parana Clinical Hospital. Ten orthopedic professionals with experience in the use of arthrometers were invited to assemble, evaluate the developed equipment, and answer a questionnaire regarding the assembly, appearance, and usability of the 3D arthrometer. Results At the end of the project, the arthrometer was successfully assembled from 3D-printed and unprinted parts, with an approximate cost of US$30 per device. All participants were able to assemble the 3D arthrometer with the instructions provided, and only one participant requested the instructor's assistance once during assembly. Regarding use, all participants were able to perform the arthrometry successfully and without the need for any assistance. Regarding face validity, we obtained a high degree of agreement among participants regarding the ease of assembly, good appearance, ease of use, and practicality of the equipment. Conclusion Using 3D printing technology to fabricate a knee arthrometer is feasible, resulting in an inexpensive and accessible tool.