[Osteotomies around the knee: preoperative planning using CT-based three-dimensional analysis, patient-specific cutting and reduction guides].

Abstract

Objective: The goal of osteotomy is either to restore pretraumatic anatomic conditions or to shift the load to less affected compartments.

Indications: Indications for computer-assisted 3D analysis and the use of patient-specific osteotomy and reduction guides include "simple" deformities and, in particular, multidimensional complex (especially posttraumatic) deformities.

Contraindications: General contraindications for performing a computed tomography (CT) scan or for an open approach for performing the surgery.

Surgical technique: Based on CT examinations of the affected and, if necessary, the contralateral healthy extremity as a healthy template (including hip, knee, and ankle joints), 3D computer models are generated, which are used for 3D analysis of the deformity as well as for calculation of the correction parameters. For the exact and simplified intraoperative implementation of the preoperative plan, individualized guides for the osteotomy and the reduction are produced by 3D printing.

Postoperative management: Partial weight-bearing from the first postoperative day. Increasing load after the first x‑ray control 6 weeks postoperatively. No limitation of the range of motion.

Results: There are several studies that have analyzed the accuracy of the implementation of the planned correction for corrective osteotomies around the knee joint with the use of patient-specific instruments with promising results.