[Treatment of tibial insertion avulsion fracture of anterior cruciate ligament involving anterior root of lateral meniscus with multi-point fixation with anchor and suture]

Objective

To investigate the effectiveness of arthroscopic multi-point fixation with anchor and suture in the treatment of tibial insertion avulsion fracture of anterior cruciate ligament (ACL) involving the anterior root of lateral meniscus (LM).

Methods

A retrospective analysis was conducted on the clinical data of 28 patients with tibial insertion avulsion fracture of ACL involving the anterior root of LM who were treated with arthroscopic multi-point fixation with anchor and suture between October 2017 and January 2023. There were 12 males and 16 females with the mean age of 26 years (range, 13-57 years). There were 20 cases of sports injury and 8 cases of traffic accident injury. In 2 cases of old fracture, the time from injury to operation was 45 days and 90 days, respectively; in 26 cases of fresh fracture, the time from injury to operation was 3-20 days (mean, 6.7 days). According to the Meyers-McKeever classification, there were 4 cases of type Ⅱ, 11 cases of type Ⅲ, and 13 cases of type Ⅳ. The preoperative Lysholm knee function score was 42.1±9.0, the International Knee Documentation Committee (IKDC) score was 40.0±7.3, and the Tegner score was 0.7±0.7.

Results

All operations were successfully completed, and the incisions healed by first intention. All the 28 patients were followed up 5-60 months (mean, 20.4 months). During the follow-up, there was nocomplication such as infection, vascular or nerve injury, loosening or breakage of internal fixator, or stiffness of knee joint. Postoperative X-ray films showed satisfactory fracture reduction and firm fixation. All fractures healed clinically, and the healing time was 8-16 weeks (mean, 10.3 weeks). At last follow-up, Lachman test and anterior drawer test were negative. At last follow-up, Lysholm knee function score was 92.4±5.5, IKDC score was 91.6±4.4, and Tegner score was 5.2±1.1, which significantly improved when compared with preoperative scores ( t=-22.899, P<0.001; t=-29.870, P<0.001; t=-19.979, P<0.001).

Conclusion

Multi-point fixation with anchor and suture in the treatment of tibial insertion avulsion fracture of ACL involving the anterior root of LM can not only fix the LM, but also effectively reduce and fix the avulsion fracture, which can obtain good effectiveness.

[Molecular dynamics simulation of force-regulated interaction between talin and Rap1b]

The binding of talin-F0 domain to ras-related protein 1b (Rap1b) plays an important role in the formation of thrombosis. However, since talin is a force-sensitive protein, it remains unclear whether and how force regulates the talin-F0/Rap1b interaction. To explore the effect of force on the binding affinity and the dynamics mechanisms of talin-F0/Rap1b, molecular dynamics simulation was used to observe and compare the changes in functional and conformational information of the complex under different forces. Our results showed that when the complex was subjected to tensile forces, there were at least two dissociation pathways with significantly different mechanical strengths. The key event determining the mechanical strength difference between the two pathways was whether the β4 sheet of the F0 domain was pulled away from the original β1-β4 parallel structure. As the force increased, the talin-F0/Rap1b interaction first strengthened and then weakened, exhibiting the signature of a transition from catch bonds to slip bonds. The mechanical load of 20 pN increased the interaction index of two residue pairs, ASP 54-ARG 41 and GLN 18-THR 65, which resulted in a significant increase in the affinity of the complex. This study predicts the regulatory mechanism of the talin-F0/Rap1b interaction by forces in the intracellular environment and provides novel ideas for the treatment of related diseases and drug development.

[Three-dimensional spatial measurement versus conventional CT planning in laparoscopic partial nephrectomy for renal tumors]

OBJECTIVE

To analyze the advantages of spatial measurement of anatomical parameters in a 3D model in surgical planning for laparoscopic partial nephrectomy (LPN).

METHODS

From February, 2016 to October, 2017, 37 patients diagnosed with T1 renal mass underwent LPN based on 3D reconstruction after enhanced CT scanning using the Uromedix-3D system (group A), and another 38 patients received LPN with conventional CT planning (group B). The anatomical parameters were measured in the reconstructed 3D model and the demographic data, surgical outcome and postoperative data were compared between the two groups.

RESULTS

In group A, the average time for 3D model reconstruction was (29.3∓9.7) min; the length, width and depth of the renal defect in 3D model were 3.2∓1.1 cm, 2.6∓0.9 cm and 1.7∓0.7 cm, respectively; The distance of the tumor from the collecting system was 3.8∓2.2 mm; The mean R.E.N.A.L score of the patients was 7∓1.5, and 3 patients had accessory renal artery and 2 had early branching of the renal artery. LPNs were completed via the retroperitoneal approach in all the 75 patients without conversion to open or total nephrectomy. Group A and group B showed significant differences in warm ischemic time (26.7∓6.4 vs 31.9∓7.0 min), tumor-excision time (8.4∓2.6 vs 10.4∓2.8 min), renal defect suture time (18.3∓3.9 vs 21.5∓3.4 min), 24-h volume of retroperitoneal drainage (88.6∓40.2 vs 134.3∓58.3 mL) and 48-h volume of retroperitoneal drainage (127.9∓54.5 vs 198.1∓86.3 mL), but not in the demographic data, operation time, intraoperative blood loss or postoperative hospital stay.

CONCLUSIONS

3D reconstruction of the renal masses can be completed efficiently and accurately using this system. Compared with conventional CT-based measurement, 3D spatial measurement of the anatomical structures helps to increase the precision in the performance of LPN and reduce the warm ischemia time.