RESUMO
Background: The graft bending angle created by the graft and the tibial tunnel has inevitably occurred during the transtibial posterior cruciate ligament (PCL) reconstruction. However, few studies quantitively analyzed this angle. This study aimed to (I) explore the optimal tibial tunnel placement to maximize the graft bending angle in the PCL reconstruction; (II) reveal the effect of the tibial tunnel placement on the graft bending angle. Methods: This was an in-vitro surgical simulation study based on the three-dimensional (3D) computed tomography (CT). A total of 55 patients who took CT scanning for knee injuries were selected (April 2020 to January 2022) from the local hospital database for review. The 3D knee models were established on the Mimics software based on the knees' CT data. Using the Rhinoceros software to simulate the transtibial PCL reconstruction on the 3D CT knee model. The anteromedial and anterolateral tibial tunnel approaches were simulated with different tibial tunnel angle. The graft bending angle and tibial tunnel length (TTL) with different tibial tunnel angles were quantitively analyzed. Results: The graft bending angle in anterolateral approach with a 50° tibial tunnel angle was significantly greater than it in anteromedial approach with a 60° tibial tunnel angle (P<0.001). There was no difference of the graft bending angle between the anterolateral approach with a 40° tibial tunnel angle and the anteromedial approach with a 60° tibial tunnel angle (P>0.05). The graft bending angle showed a strong correlation with the tibial tunnel angle (for anteromedial approach: r=0.759, P<0.001; for anterolateral approach: r=0.702, P<0.001). The best-fit equation to calculate the graft bending angle based on the tibial tunnel angle was Y = 0.89*X + 59.05 in anteromedial tibial tunnel approach (r2=0.576), and was Y = 0.78*X + 80.21 anterolateral tibial tunnel approach (r2=0.493). Conclusions: The graft bending angle and TTL will significantly increase as the tibial tunnel angle becomes greater. Maximizing the tibial tunnel angle (50° tibial tunnel angle) in the anterolateral approach could provide the greatest graft bending angle in the PCL reconstruction. No matter how the tibial tunnel angle is changed in the anteromedial approach, using anterolateral approach might reduce the killer turn effect more effectively than using anteromedial approach.
RESUMO
BACKGROUND: Tranexamic acid (TXA), delivered intravenously or topically, has been shown to reduce blood loss, the need for transfusion, and relevant healthcare costs when administered in primary standard total hip arthroplasty (THA). Whether the same is true of oral TXA is unclear, the purpose of this study was to determine if oral tranexamic acid is equivalent to intravenous TXA in the case of patients undergoing THA via the direct anterior approach. METHODS: In this prospective randomized controlled trial, 120 patients undergoing primary THA by the direct anterior approach were randomized to receive oral TXA (two doses of 20 mg/kg), intravenous TXA (two doses of 15 mg/kg), or no TXA. Primary outcomes were haemoglobin drop, haematocrit levels, total blood loss, intra-operative blood loss, need for transfusion, and volume transfused. Secondary outcomes included thromboembolic events, wound complications, the length of post-operative hospital stay, and 30-day readmission. RESULTS: Demographic characteristics were similar among the three patient groups (p > 0.05, n = 40 per group). Haemoglobin drop, haematocrit levels, total blood loss, and intra-operative blood loss were similar in the oral and intravenous groups (p > 0.05), and significantly smaller than in the control group (p < 0.05). Transfusions were given to significantly fewer patients in the oral group (3%) and intravenous group (6%) than in the control group (27%, p = 0.01). Costs of TXA and transfusions were significantly lower in the oral group than the intravenous group (p < 0.05). The three groups were similar in thromboembolic events, wound complications, the length of post-operative hospital stay, and 30-day readmission (p > 0.05). CONCLUSION: Oral TXA shows similar efficacy and safety as intravenous TXA for reducing haemoglobin drop, haematocrit levels, total blood loss, and transfusion rate following THA by the direct anterior approach. Therefore, the much less-expensive oral formulation may be superior to the intravenous form.