Are three-dimensional patient-specific cutting guides for open wedge high tibial osteotomy accurate? An in vitro study.

BACKGROUND: The aim of this in vitro study was to assess the accuracy of three-dimensional patient-specific cutting guides for open wedge high tibial osteotomy (OWHTO) to provide the planned correction in both frontal and sagittal planes. METHODS: Ten cadaveric tibias underwent OWHTO performed using a patient-specific cutting guide based on 3D preoperative planning. An initial CT scan of the tibias was performed, and after segmentation, 3D geometrical models of the pre-OWHTO tibias were obtained. Reference planes were defined, and OWHTO virtually planned to then design patient-specific cutting guides. OWHTO were performed using the patient-specific cutting guides. The patient-specific cutting guide controls the cut and the correction of the OWHTO in both planes. 3D models of post-OWHTO tibias were created after a postoperative CT scan. Geometrical post-OWHTO 3D models were superimposed on pre-OWHTO 3D models. Mechanical medial proximal tibial angle (mMPTA) in the frontal plane and posterior tibial slope (PTS) in the sagittal plane were compared between planned-OWHTO and post-OWHTO 3D reconstructions relative to the pre-OWHTO reference planes and axis. Pearson's and Lin's correlation tests were performed to assess precision and accuracy of patient-specific cutting guides. RESULTS: The mean difference between post-OWHTO and planned-OWHTO was 0.2° (max 0.5°, SD 0.3°) in the frontal plane and - 0.1° (max 0.8°, SD 0.5°) in the sagittal plane. Statistically significant correlations were found between the planned-OWHTO and post-OWHTO configurations for the mMPTA (p < 0.0001) and PTS (p < 0.0001) measurements, and the bias correction factor was 0.99 in both planes. CONCLUSIONS: 3D patient-specific cutting guides for OWHTO-based 3D virtual planning is a reliable and accurate method of achieving multiplanar correction in both frontal and sagittal planes.

Balloon tibioplasty for reduction of depressed tibial plateau fractures: Preliminary radiographic and clinical results.

PURPOSE: In vitro studies have shown promising results for balloon-guided inflation tibioplasty. It was our hypothesis that this technique may be safe and effective for use in depressed lateral tibial plateau fracture. METHODS: We performed a prospective study of all patients suffering from a depressed lateral tibial plateau fracture, managed in our institution with inflation tibioplasty and a resorbable calcium phosphate bone substitute injection, between January 2012 and December 2013. Twenty patients, mean age 54.3 ± 12. 8 years, suffering from a depressed lateral tibial plateau fracture (Schatzker type II and III) were included. We then aimed to evaluate at a minimum follow-up of one year: (1) the rate of complications, (2) the clinical outcome (Knee Injury and Osteoarthritis Outcome (KOO) and 12-Item Short Form Health Survey (SF-12) scores); and (3) the radiographic outcome (evaluated by CT-scan). RESULTS: No peri-operative complications occurred. In one patient, calcium phosphate substitute was found in the infrapatellar fat pad on post-operative radiography with no clinical or radiographic consequences at one year. At one year after surgery, the KOO subscores were: Pain 80 (range 64-93), other symptoms 81.3 (69-93), daily living activities 81.9 (46-99), sport 65.83 (20-100), and quality of life 67.04 (31-100). The SF-12 activity component was 40.4 (28.6-52.2) and SF-12 mental component 47.71 (28 - 67.1). The mean depressed step-off of the lateral joint decreased from 10.7 ± 4.8 mm pre-operatively to 2.7 ± 1.7 mm post-operatively (p < 0.0001). CONCLUSION: Our observations suggest that the use of balloon-guided inflation tibioplasty with injection of a resorbable bone substitute is safe, and results in a high rate of anatomic reduction and good clinical outcomes in patients with depressed tibial plateau fractures. LEVEL OF EVIDENCE: Therapeutic Level IV.