P163 - Patient specific cutting guides for High Tibia opening wedge osteotomy are precise and reliable.
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
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.
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.