Objective To explore the feasibility of pre-implantation of high-intensity suture into tendon grafts to prevent postoperative graft relaxation and creep in anterior cruciate ligament (ACL) reconstruction. Methods Thirty-six specimens of ACL reconstruction graft were made using adult swine’s Achilles tendon. All the specimens were randomly divided into experimental group (groups A and C) and control group (groups B and D), 9 specimens each group. One double-strand Ultrabraid No.2 high-intensity suture was pre-implanted into the grafts of groups A and C. Groups A and B underwent a 1 000-cycles load test while groups C and D underwent a 3 000-cycles load test. Then a pull-out test was performed until failure. The displacements at different cycles (100, 500, 1 000, 2 000, and 3 000) in all groups and yield loads of groups C and D were measured and analyzed. Results The displacement of group A was significantly smaller than that of group B at the cycles of 100, 500, and 1 000 (P<0.05); the displacement of group C was significantly smaller than that of group D at every cycle (P<0.05). Additionally, the yield load of group C was significantly higher than that of group D (t=4.816,P=0.001). Conclusion Pre-implantation of high-intensity suture into tendon grafts play an important role in the prevention of postoperative graft creep and relaxation in ACL reconstruction.
ObjectiveTo explore the effects of cryopreservation on the cell survival rate, cell viability, early apoptosis, migration ability, and tendon-related marker expression of tendon-derived stem cells (TDSCs) in rat patellar tendons.MethodsThe patellar tendon tissues were harvested from 12 4-month-old male Sprague Dawley rats; 12 patellar tendon tissues from 6 rats were cryopreserved (the experimental group), and the other 12 patellar tendon tissues were not treated (the control group). The patellar tendons were digested with 0.3% type I collagenase to obtain nucleated cells. The survival rate of nucleated cells was detected by trypan blue exclusion assay, and colony-forming ability by crystal violet staining. TDSCs were isolated and cultured to passage 3 (P3). The cell viability of TDSCs was detected by Alamar Blue method, the early apoptosis by Annexin V-FITC/PI assay, the cell migration ability by Transwell method, and the mRNA expressions of tendon-related markers [collagen type I (Col1α1), scleraxis (Scx), and tenomodulin (Tnmd)] by real-time quantitative PCR.ResultsThe survival rate of nucleated cells was 91.00%±3.63% in the control group, and was 61.65%±4.76% in the experimental group, showing significant difference (t=12.010, P=0.000). The formation of the primary nucleated cell clones was observed in 2 groups. At 12 days, the number of colonies forming of the experimental group [(8.41±0.33)/1 000 nucleated cells] was significantly lower than that of the control group [(15.19±0.47)/1 000 nucleated cells] (t=28.910, P=0.000). The percentage of TDSCs in the active nucleated cells in the experimental group (1.37%±0.09%) was significantly lower than that in the control group (1.67%±0.10%) (t=5.508, P=0.003). The growth trend of TDSCs (P3) in the 2 groups was consistent within 14 days. There was no significant difference in absorbance (A) value between 2 groups at each time point (P>0.05). The early apoptotic rate of TDSCs was 1.67%±0.06% in the experimental group and was 1.63%±0.06% in the control group, showing no significant difference (t=0.707, P=0.519). Under microscope, TDSCs adhered to the lower chamber of the Transwell chamber; the number of cells was 445.00±9.70 in the experimental group and was 451.50±12.66 in the control group, showing no significant difference (t=0.998, P=0.342). The relative mRNA expressions of Col1α1, Scx, and Tnmd were 3.498±0.065, 0.062±0.002, and (4.211±0.211)×10–5 in the experimental group and were 3.499±0.113, 0.062±0.001, and (4.341±0.274)×10–5 in the con-trol group, showing no significant difference (t=0.013, P=0.991; t=0.042, P=0.969; t=0.653, P=0.549).ConclusionThe survival rate of nucleated cells in cryopreserved rat tendon tissues is lower, but a large number of active TDSCs, and its cell viability, early apoptosis rate, migration ability in vitro, and cell tenogenic differentiation ability are remained.
ObjectiveTo investigate the clinical application and effectiveness of V-Y plasty combined with gastrocnemius aponeurosis turndown in the repair of Myerson type Ⅲ chronic Achilles tendon rupture combined with large tendon defect. MethodsBetween February 2008 and July 2019, 25 patients underwent the V-Y plasty combined with gastrocnemius aponeurosis turndown to treat the Myerson type Ⅲ chronic Achilles tendon rupture. There were 21 males and 4 females. The age ranged from 17 to 56 years, with an average of 34.3 years. Achilles tendon rupture was caused by sports injury in all patients, and the duration from Achilles tendon rupture to operation was 31-70 days, with an average of 53.9 days. After resection of fibrous scar tissue, the distance of Achilles tendon defect was 7-12 cm, with an average of 9.04 cm. The clinical results were evaluated by the Achilles tendon total rupture score (ATRS), American Orthopaedic Foot and Ankle Society (AOFAS) score, dorsiflexion and heel raise height before and after operation. Results The donor and recipient wounds of all 25 cases healed by first intention after operation. All patients were followed up 24 months. During the follow-up, 3 patients developed mild wound infection, which was cured after anti-infection treatment. One patient had Achilles tendon exposure, which was cured after local flap transfer and repair. Ultrasound and MRI reexamination at 3-12 months after operation showed no Achilles tendon elongation, adhesion, or re-rupture. At 24 months after operation, the ATRS score, AOFAS score, dorsiflexion and heel raise height of affected side significantly improved when compared with those before operation (P<0.05). However, the dorsiflexion and heel raise height of affected side were still significantly worse than those of the healthy side (P<0.05). ConclusionV-Y plasty combined with gastrocnemius aponeurosis turndown to repair the chronic Achilles tendon rupture can achieve good effectiveness, and the Achilles tendon function significantly improved after repair. However, the procedure is more invasive and has a long duration of intraoperative wound exposure, causing an increased risk of infection, and the aesthetic is not good.
Objective To investigate the feasibility of establishing an anterior cruciate ligament (ACL) reconstruction model using hamstring tendon autograft in cynomolgus monkeys. Methods Twelve healthy adult male cynomolgus monkeys, weighing 8-13 kg, were randomly divided into two groups (n=6). In the experimental group, the ACL reconstruction model of the right lower limb was prepared by using a single bundle of hamstring tendon, and the ACL of the right lower limb was only cut off in the control group. The survival of animals in the two groups was observed after operation. Before operation and at 3, 6, and 12 months after operation, the knee range of motion, thigh circumference, and calf circumference of the two groups were measured; the anterior tibial translation D-value (ATTD) was measured by Ligs joint ligament digital body examination instrument under the loads of 13-20 N, respectively. At the same time, the experimental group underwent MRI examination to observe the graft morphology and the signal/ noise quotient (SNQ) was caculated. Results All animals survived to the end of the experiment. In the experimental group, the knee range of motion, thigh circumference, and calf circumference decreased first and then gradually increased after operation; the above indexes were significantly lower at 3 and 6 months after operation than before operation (P<0.05), and no significant difference was found between pre-operation and 12 months after operation (P>0.05). In the control group, there was no significant change in knee range of motion after operation, showing no significant difference between pre- and post-operation (P>0.05), but the thigh circumference and calf circumference gradually significantly decreased with time (P<0.05), and the difference was significant when compared with those before operation (P<0.05). At 6 and 12 months after operation, the thigh circumference and calf circumference were significantly larger in the experimental group than in the control group (P<0.05). At 3 and 6 months after operation, the knee range of motion was significantly smaller in the experimental group than in the control group (P<0.05). Under the loading condition of 13-20 N, the ATTD in the experimental group increased first and then decreased after operation; and the ATTD significantly increased at 3, 6 months after operation when compared with the value before operation (P<0.05). But there was no significant difference between the pre-operation and 12 months after operation (P>0.05). There was no significant change in ATTD in the control group at 3, 6, and 12 months after operation (P>0.05), and which were significantly higher than those before operation (P<0.05). At each time point after operation, the ATTD was significantly smaller in the experimental group than in the control group under the same load (P<0.05). The MRI examination of the experimental group showed that the ACL boundary gradually became clear after reconstruction and was covered by the synovial membrane. The SNQ at each time point after operation was significantly higher than that before operation, but gradually decreased with time, and the differences between time points were significant (P<0.05). Conclusion The ACL reconstruction model in cynomolgus monkey with autogenous hamstring tendon transplantation was successfully established.