Ján Kočiš

Outcomes After Conventional Versus Computer-Navigated Anterior Cruciate Ligament Reconstruction

PURPOSE The purpose of this prospective randomized study was to assess biomechanical, radiographic, and functional results after single-bundle anterior cruciate ligament (ACL) reconstruction by use of a navigation system. METHODS ACL reconstruction was performed by use of the OrthoPilot navigation system (B. Braun-Aesculap, Tuttlingen, Germany) in 40 patients (group 1); and in another 40 patients, surgery was done by the standard manual targeting technique (group 2). The anterior laxity was measured with a KT-1000 arthrometer (MEDmetric, San Diego, CA). Femoral and tibial tunnel position was evaluated radiologically according to the method described by Bernard and Hertel and by Harner et al., respectively. The questionnaire-based Lysholm and International Knee Documentation Committee scales were included to compare the functional state in both groups. RESULTS The knees in group 1 were as stable as those in group 2 during the arthrometer testing, with a lower value of dispersion. The postoperative Lysholm and International Knee Documentation Committee scores had the same value in both groups. Statistical differences existed with regard to anterior-posterior femoral tunnel placement when the navigated and standard techniques were compared; in the navigated group, more exact results were found. No significant complications were observed. CONCLUSIONS The only difference that we found between the navigated and standard groups was in radiographic tunnel position measurement. The computer-assisted navigation technique in our study resulted in more accurate tunnel placement in the femur (but not the tibia) than the traditional arthroscopic technique. However, the performed standard radiographic measurements are of limited precision in principle. Functional scales and stability tests gave similar results in both groups. LEVEL OF EVIDENCE Level I, therapeutic study.

Minimally invasive thoracoscopic approach to thoracolumbar junction fractures

AIMS A retrospective analysis of patients with thoracolumbar junction fractures who underwent video-assisted thoracoscopic surgery via a minimally invasive approach (minithoracotomy) for reconstruction of the anterior spinal column. METHODS Between 2002 and 2014, a total of 176 patients were treated by this technique. The patients received either posterior stabilization and, at the second stage, the minimally invasive technique via an anterior approach, or the minimally invasive anterior procedure alone. RESULTS In the anterior procedure, the average operative time was 90 min. (50 to 130 min). Bony fusion without complications was achieved in all patients within a year of surgery. The loss of correction after the anterior procedure with an allograft or titanium cage was up to 2 degrees at two years follow-up. CONCLUSION The minimally invasive approach (minithoracotomy up to 6-7 cm) combined with thoracoscopy is an alternative to an exclusively endoscopic technique enabling us to provide safe surgical treatment of the anterior spinal column.

Biomechanical Testing of Spinal Segment Fixed by Arcofix System on the Swine Spine

Study Design An in vitro biomechanical study. Purpose To evaluate the mechanical properties of the spinal segment in the intact, injured, and stabilized state after fixation by an Arcofix implant. Overview of Literature Several types of thoracolumbar spine injury necessitates anterior instrumentation. The Arcofix plate represents the latest generation of angular stablity systems. The biomechanical properties of these implants have not been sufficiently studied yet. Methods A total of ten porcine specimens (levels Th12-L3) were prepared. The tests were performed for intact, injured, and implanted specimens. In each state, the specimen was subjected to a tension load of a prescribed force, and subsequently, twisted by a given angle. The force load was 200 N. The torsion load had a deformation character, i.e., the control variable was the twisting angle and the measured variable was the moment of a couple. The amplitude of the load alternating cycle was 3°. Another parameter that was evaluated was the area of the hysteresis loop. The area corresponds to the deformation energy which is dissipated during the cycle. Results A statistically significant difference was found between the intact and injured states as well as between the injured and implanted specimens. The statistical evaluation also showed a statistically different value of the hysteresis loop area. In the case of instability, the area decreased to 33% of the physiological value. For the implanted sample, the area increased to 170% of the physiological value. Conclusions The Arcofix implant with its parameters appears to be suitable and sufficiently stable for the treatment of the anterior column of the spine.