Arthrex (Germany)

IntroductionCurrently, the gold standard for the treatment of AO type B3 cervical spine injuries is anterior cervical discectomy and fusion (ACDF), leading to an iatrogenic spondylodesis of the affected segment and ultimately bearing the risk of long-term morbidity. This study evaluates the biomechanical properties of a combination of a cervical total disc replacement (CTDR) with anterior fiber tape augmentation for the treatment of AO type B3 injuries in comparison to ACDF.Methods14 human cadaveric cervical spine specimens (C5/6) were biomechanically tested under four different conditions: native, after simulation of an AO type B3 injury, after ACDF and CTDR + FiberTape®. All conditions were tested in the sagittal, frontal, and transversal plane with a load of 2.25Nm and the dislocation recorded. The mean value of range of motion (ROM) was calculated and analysed to identify differences in ROM and the neutral zone.ResultsIn flexion/extension, native testing showed a mean deflection of 11.2° ± 3.3°, the AO type B3 injury of 13.7° ± 2.9°, the ACDF of 6.7° ± 3.8° and the CTDR + tape of 9.3° ± 2.9°. Comparing both the injured specimens to the ACDF group (p < 0.001) and the injured to the tape group (p = 0.005) as well as the native to the ACDF group (p = 0.004), the mean values revealed to be significant. Lateral bending revealed a ROM of 6.8° ± 2.7° in the native, 7.7° ± 2.4° in the injured group, 4.7° ± 2.8° after ACDF, and 5.6° ± 2.4° after CTDR + tape, whereby the injured group values were significantly higher than those after ACDF (p = 0.018). The rotation showed a mean ROM of 5.6° ± 2.8° in the native and 5.8° ± 2.6° in the injured group, 4.0° ± 2.1° after ACDF and 6.3° ± 2.8° after CTDR + tape, without significant differences.ConclusionThe combination of a CTDR + FiberTape proved to stabilize AO type B3 cervical spine injury adequately in the most compromised sagittal plane while maintaining micro-mobility and approaching physiological segment mobility.

Background:Despite the rare entity of sternoclavicular joint (SCJ) instability, a variety of different reconstruction techniques for SCJ dislocations have been described. A technique with oblique drilling has been proposed to reduce intraoperative risks.Purpose:To biomechanically investigate different cerclage reconstruction techniques and the benefit of additional reinforcement using suture tape.Study Design:Controlled laboratory study.Methods:Reconstructed artificial bone specimens were mounted on a mechanical testing machine. They were subjected to anterior and posterior translation, analyzing ultimate strength, displacement, stiffness, and elongation. For stage 1, different angulations of the drill tunnels through the sternum and clavicle were compared. Straight drill tunnels from anterior to posterior were compared with 45° oblique drill tunnels. For stage 2, three different materials for cerclage reconstruction were compared: (1) suture tape alone (FT group), (2) tendon graft alone (tendon group), and (3) tendon graft with suture tape augmentation (tendon+FT group).Results:For the FT group, in the anterior and posterior directions, straight drill holes resulted in a significantly higher load to failure (936.9 ± 122.5 N) compared with oblique ones (434.5 ± 20.2 N) (P < .0001). During cyclic testing, all specimens with straight drill holes survived the 5- to 550-N step, while all specimens with oblique ones failed during the 5- to 450-N step. Analyzing the graft material choice, the mean load to failure was 556.6 ± 174.3 N for the tendon group, 936.9 ± 122.5 N for the FT group, and 767.0 ± 110.7 N for the tendon+FT group (P = .089). The stiffness of the tendon+FT group was significantly lower than that of the FT group and significantly higher than that of the tendon group.Conclusion:Oblique tunnel placement during SCJ reconstruction, while reducing the intraoperative risk, results in decreased primary stability of the construct. Tendon graft reconstruction with suture tape augmentation leads to enhanced stability and optimizes biomechanical properties of the construct.Clinical Relevance:The surgical technique with straight drill holes has superior initial biomechanical properties and may likewise produce superior clinical outcomes in the treatment of SCJ instability. Suture tape augmentation can provide additional stability to reconstruction procedures.

Background:Historically, tendon-to-bone fixation has relied on knot tying. However, considerable variability exists in knot-tying strength among surgeons.Purpose/Hypothesis:The purpose of this study was to compare the biomechanical properties of knotted and knotless fixation and to evaluate variability among surgeons. The hypothesis was that knotless constructs would be stronger and have less variability as compared with knotted constructs.Study Design:Controlled laboratory study.Methods:A total of 34 orthopaedic surgeons participated in a laboratory study to compare knotted and knotless constructs, where 104 knotted constructs were performed with No. 2 suture, 21 knotless constructs with No. 2 suture (K2 group), and 79 knotless constructs with suture tape (KT group). Mechanical testing was performed to compare load at 3 mm of displacement, load to failure, and stiffness of each construct.Results:The mean load at 3 mm of displacement was greatest in the KT group, with significant differences among all 3 groups (P < .001). Load to failure was significantly greater in the KT group as compared with the K2 group and the knotted group (P < .001), but there was no difference between the K2 and knotted groups (P ≥ .999). Stiffness and displacement were also greatest in the KT group. Based on the F test, the variance in load to failure was significantly different between the knotted and knotless constructs, with the knotted group demonstrating greater variability (SD, 94 N) than the KT (SD, 38 N) and K2 (SD, 17 N) groups (P < .001).Conclusion:Knotless fixation with suture tape had improved biomechanical performance as compared with knots or knotless fixation with No. 2 suture. In addition, knotless fixation had less variability in biomechanical properties among multiple surgeons.Clinical Relevance:This study may be relevant for surgeons choosing between knotted and knotless constructs as well as for considerations in the design of rotator cuff repair constructs.