P163 - Patient specific cutting guides for High Tibia opening wedge osteotomy are precise and reliable.
Abstract
Purpose
High Tibial Opening Wegde Osteotomy (HTowO) Conventional instrumentations are often limited by correction errors specifically when a multi-planar (Frontal and sagittal plane) correction is required.
We hypothesized that Patient specific cutting guide (PSCG) in high tibial valgus osteotomy allows accurate correction (<2° difference) as compared to the preoperative planning.
Methods and Materials
Between 02/2016 and 09/2018 the first 100 patients operated using PSCG HTowO in our department, were prospectively enrolled in this reliability study. Preoperatively, planning was based on long-axis X-ray and CT scan with 3-D reconstruction. Custom guides were obtained, following surgeon instruction in a step-by-step process. The PSCG was designed to guide 1/ osteotomy cut 2/ (anatomical plate) locked-screws holes position 3/ K-Wire insertion to stop the saw and protect the hinge during HTO opening
Patients’ mean age was 46years (31-59), BMI of 26 kg/m2 (24.2-39.4) and only patients with isolated medial femoro-tibial Ahlbäck <3 arthritis were included. Accuracy analysis was done through a 3D registration process between preoperative planning and the correction obtained on both CT-Scan and Long-axis x-rays
Results
For every patients the surgical procedure was entirely achieved using customized cutting guide. The mean HKA was 182.3° (180-185°), mean MPTA 94° (88-98°) and mean TS 7,1° (4-11°). In 97 cases, a difference <2° between the desired and obtained correction was observed when 3D analysis in the three planes of space, in three outliers patients tibial slopes were insufficiently corrected (mean difference 4°; range 3-4°). ICC between the postoperative and planning measures were 0.78 [0.72 to 0.85] for HKA 0.98 [0.92 to 0.99] for MPTA and 0.96 [0.79 to 0, 99] for TS.
Conclusion
PSCG guides allow optimum correction in reliable and very precise manner. Larger scale studies are now need to confirm that those systems provide a direct clinical benefit to patients suffering from low grade medial knee arthritis.