Osteotomy configuration of the proximal wedge and analysis of the affecting factors in the medial open-wedge high tibial osteotomy.

PURPOSE: The purposes of this study were (1) to confirm the disparity of the measured thickness at the lateral hinge between anterior-posterior (AP) radiograph and 3D CT image, (2) to evaluate the affecting factors, and (3) to evaluate the differences between uniplanar and biplanar osteotomies. METHODS: From 2012 to 2014, a prospective comparative study was performed with 30 patients who received uniplanar osteotomy (group I) and 35 patients who received biplanar osteotomy (group II). For measurement of the proximal wedge, postoperative AP radiograph and 3D CT images were used. In the AP radiograph, medial and lateral bony bridge thicknesses were measured. In the 3D CT, the anterior and posterior images parallel to the coronal plane were selected for the evaluation. Coronal osteotomy slope was measured with the anterior image of the 3D CT scan. Sagittal osteotomy slope was measured with the sagittal section of the CT scan. RESULTS: Differences between the lateral bony bridge thicknesses measured in AP radiograph and the posterolateral posterolateral bony bridge thicknesses measured in 3D CT were statistically significant in both groups. Negative correlation was observed in the biplanar osteotomy group. Differences of the sagittal osteotomy slope from the native tibial slope showed negative correlation in the biplanar osteotomy group. CONCLUSION: Thickness of the posterolateral bony bridge was smaller compared to the observed thickness on the AP radiograph image that is routinely used for the follow-up. The thickness would be getting smaller if osteotomy is performed with an abrupt angle on the coronal plane and reverse slope on the sagittal plane. Therefore, osteotomy with abrupt angle on the coronal plane and reverse slope on the sagittal plane should be avoided for the proper thickness of the posterolateral bony bridge. LEVEL OF EVIDENCE: III.

Comparison of Tibial Tunnel Techniques in Posterior Cruciate Ligament Reconstruction: C-Arm Versus Anatomic Fovea Landmark.

PURPOSE: To evaluate the accuracy of the posterior cruciate ligament (PCL) fovea landmark against conventional fluoroscopic pin placement retrospectively using 3-dimensional computed tomography (3D CT). METHODS: This retrospective comparison focused on the tibial tunnel locations determined in consecutive 26 patients using the fluoroscopic imaging technique (group I) and in consecutive 23 patients using the PCL fovea landmark technique without the help of the fluoroscopy (group II) for tibial tunnel formation. The 3D surface-modeled CT images that appropriately located the position of the PCL fovea on the tibial plateau were used. Ratios between total length of the fovea and length of the tunnel center from the medial border (coronal) and posterior edge (sagittal) were evaluated. RESULTS: The ratios between sagittal tunnel length and total sagittal length for groups I and II were 35.4% ± 12.2% and 44.1% ± 23.1%, respectively (P = .07). The ratios between the coronal tunnel lengths and total coronal lengths for groups I and II were 47.3% ± 9.2% and 57.3% ± 18.1%, respectively: group II showed a more laterally positioned tibial tunnel than did group I (P = .03). CONCLUSIONS: A more laterally located tibial tunnel was produced using the PCL fovea landmark technique. However, the differences in centers were small and probably not clinically relevant. Therefore, the PCL fovea landmark technique might be an alternative method to the fluoroscopic imaging technique for locating the anatomic tibial tunnel during transtibial PCL reconstruction. LEVEL OF EVIDENCE: Level III, retrospective comparative study.