Wang Hong, Meng Chunqing, Duan Deyu, Yang Shuhua, Ye Shunan, Shao Zengwu, the selection of grafts is one of the most important factors limiting the outcome of reconstructive surgery after knee ligament injury, and it is also a hot spot of research in recent years. As the incidence of knee ligament injuries increases and the degree of injury becomes more complicated, especially after simultaneous injuries to the anterior and posterior cruciate ligament (ACL) and Posterior cruciate ligament (PCL), autologous tissue transplantation is often difficult to meet the needs of ligament reconstruction, and autologous tissues can cause some damage when taken. The autologous tissue transplantation is often difficult to meet the needs of ligament reconstruction, and autologous tissues may also cause some damage, while the development of artificial and tissue-engineered ligaments is still immature, so the reconstruction of ACL and PCL ligaments by allogenic ligament or tendon grafting is receiving more and more attention [1]. satisfactory efficacy, reported as follows. Wang Hong, Department of Orthopaedics, Wuhan Union Medical College Hospital, Wuhan, China 1 Clinical data 1.1 General data 7 male cases and 3 female cases in this group; their ages ranged from 18 to 45 years old, with an average of 30.2 years old. All of them were single knee injuries, including 6 cases of left knee and 4 cases of right knee. 10 cases had clear trauma history, including 8 cases of car accident injuries and 2 cases of heavy object injuries. The main clinical symptoms were knee instability and pain. All 10 cases had swollen joints, and the anterior and posterior drawer tests and the internal rotation test were positive.The Lysholm[2] knee function score was (23.8±4.1).MRI showed ACL and PCL rupture, with medial meniscus injury in 5 cases, and with medial collateral ligament injury in 8 cases. The duration of the disease in this group ranged from 1 to 3 weeks, with an average of 1.8 weeks. The patients had manipulative correction of knee dislocation and external fixation with plaster cast before admission, but still had joint instability. 1.2 Surgical methods Conventional anterior external and anterior internal incisions were taken to enter the joint cavity, and complete knee arthroscopy was performed. After confirming that the patients had both anterior and posterior cruciate ligament ruptures, two homologous tibialis anterior tendons (Shanxi Aorui Biomaterials Co., Ltd.) were taken, which were thawed and trimmed in saline (200 ml of saline with 10 mg of dexamethasone) at room temperature. The contralateral end was marked at 3 cm with methylene blue. 1.2.1 Preparation of ACL and PCL reconstruction bone tunnels The surgeon continued the preparation of ACL and PCL bone tunnels by moderately trimming the ACL and PCL femoral and tibial end stumps with a planer knife and a plasma vaporizer knife, and then placing a stripper through the intercondylar fossa to appropriately strip the PCL tibial attachment stump. Flex the knee at 90 degrees, first make the PCL femoral tunnel, from the anterolateral portal place the femoral stop locator in the medial wall of the intercondylar fossa of the femur, the left knee 10:30-11:30, the right knee 1:30-2:30, the PCL femoral medial condylar attachment footprint as a reference, from the medial condyle of the femur drilling into the guide pin, which is 6-9 mm away from the edge of the cartilage, and then drill the femoral tunnel along the guide pin with the same diameter as the grafted tendon to the depth of 3 cm, followed by 4.5 cm of 4.5 cm. A femoral tunnel of the same diameter as the grafted tendon was drilled along the guide pin to a depth of 3 cm, which was then drilled through with a 4.5 mm hollow drill. The ACL femoral tunnel was then performed by positioning the ACL femoral tunnel locator at 11 o’clock (right knee) or 1 o’clock (left knee) on the lateral posterior wall of the intercondylar fossa in the 120-degree position with the knee flexed, drilling the guide pin through the lateral femoral condyle at the locating point, and exiting the anterolateral aspect of the femur, and then drilling the femoral tunnel of the same diameter as the grafted tendon along the guide pin to a depth of 3.5 cm, preserving the posterior wall of the lateral condyle of the femur for 2-3 mm, and then drilling through the femoral tunnel with a 4.5 mm hollow drill. hollow drill to drill through. The tibial tunnel was positioned 1-3 cm medial to the tibial tuberosity using an ACL tibial tunnel locator adjusted to a 50° angle, centered on the tibial stop fibers of the ACL, proximal to the anterior third of the intercondylar spine, and was drilled through with the same drill as the grafted tendon after drilling out the guide pin. The tibial stop PCL positioner is placed in the posterior tibial fossa at a 50° angle from the anteromedial portal, 1.5 cm below the plane of the joint line, and the guide pin is inserted 4-5 cm anteromedial to the plane of the tibial tuberosity, and the tibial tunnel is drilled with the same diameter as the grafted tendon along the guide pin. 1.2 ACL and PCL allograft tibialis anterior tendon reconstruction A double-stranded steel wire is fed into the joint cavity from outside the tibial tunnel of the PCL, and then guided out from the anterolateral portal. 4 strands of the braided suture end of the double-stranded allograft tibialis anterior tendon are pulled out from the tibial tunnel, and the grafted tendon is slowly guided through the joint and into the tibial tunnel again. The double-stranded graft tendon retractor wire is drawn from the medial femoral condyle using a perforated guide pin inserted into the femoral tunnel at the anterolateral portal, and the graft tendon is retracted into the femoral tunnel to the marking line. A guide pin is inserted parallel to the wall of the femoral tunnel and the upper edge of the graft tendon gap, and a resorbable extruded screw of the same size as the graft is screwed into the femoral tunnel along the guide pin for fixation. Endobutten of different lengths were selected according to the length of the femoral epicondylar tunnel, and a perforated guide pin with a loop of AISI 5 wire was introduced into the femoral tunnel of the ACL at 120 degrees of knee flexion from the anteromedial portal and exited from the anterolateral aspect of the thigh, bringing the loop of the tail of the pin into the articular cavity, and then the loop of the pin was withdrawn from the tibial tunnel of the ACL with a grasping forceps. The retractor wire and lifting wire of the snapped Endobutten’s graft tendon are brought into the loop of the perforated guide pin to draw it out. Forcefully lift the retractor wire to bring the EndoButton and its snapped allograft tendon from the tibial tunnel through the intra-articular into the femoral tunnel to the marking line at the time of the lift, and pull the retractor wire to the plate flap. Continuously tighten the suture outside the tunnel of the allograft tibialis anterior muscle at the tibial end of the ACL and PCL, and perform extension and flexion of the knee about 20 times. A guide pin was inserted into the tibial tunnel of the PCL at 70° of knee flexion, along which an absorbable screw of the same size as the graft was screwed in for fixation, and the ACL was fixed in the same way at 30° of knee flexion, and then the graft was fixed at the exit of the tibial end with a 2-gauge suture of the AICL to strengthen the fixation [3,4]. In the case of combined medial collateral ligament injury, the superficial layer of the ruptured medial collateral ligament was repaired with braided sutures of AIC 5 traction suture at the femoral end after posterior cruciate ligament reconstruction, and the deeper layer of the medial meniscus with the torn joint capsule and synovial rim was repaired with absorbable sutures of 1-0. The free edge tear of the medial meniscus injury was partially resected in phase. After the operation, the knee was moved, and the anterior-posterior drawer test and the medial-lateral stress test were negative. 1.3 Postoperative treatment After the operation, the knee joint was braced in the knee-extension position, and the drainage tube was removed 48 h after the operation. On the first postoperative day, straight leg raising exercise was started, 15 s each time, 60-100 times per day. Passive movement of the patella in each direction was performed 10-20 times a day. Active knee flexion from 0 to 90° was started at 4 weeks after surgery, and active knee flexion was > 90° at 6 weeks. Full weight bearing was abandoned at 12 weeks after surgery, and labor and sports were resumed after 12 months. 1.4 Statistical methods Knee function was evaluated according to the Lysholm knee function score. SPSS 12.0 software was used for statistical analysis, data were expressed as mean ± standard deviation, and paired t-test was used to compare the Lysholm scores before and after surgery. p-value was 90°. Full weight-bearing was performed at 12 weeks after the removal of the brace, and labor and sports were resumed after 12 months. Gradually adapt to the crawling substitution of autologous tissue until the mechanical properties of normal ligaments are restored. 3.5 Disadvantages and solutions of allogeneic tendon reconstruction Although the efficacy of ACL reconstruction with allogeneic and autologous tissues is similar, and has the advantages of convenient application, simple surgery, and less trauma, it is an allogeneic tissue after all, in addition to delayed tissue incorporation, insufficient loading strength, and the graft is prone to be elongated or ruptured, there are still many problems such as spread of disease, immune reaction, expansion of bone tunnel, and the price is high and the preservation and sterilization of grafts [10]. sterilization and many other problems [10]. Particular attention should be paid to disease transmission, immunogenicity, and lack of mechanical strength. Disease transmission can be avoided by better screening of donors. The process of deep cryogenic freezing and radiation sterilization can denature the major histocompatibility antigens of the cell membrane, reducing the antigenicity of the allograft tissue without affecting the mechanical properties of the allograft [11]. 3.6 Long-term efficacy of allogeneic tendon reconstruction for multiple ligament injuries Since the use of allogeneic tendon grafts for repairing multiple ligament injuries of the knee is a surgical method that has only been carried out in the last few years. There is no large-scale long-term follow-up data at home and abroad. Therefore, there is a lack of valid data to evaluate the long-term efficacy of allogeneic tendon reconstruction for multiple ligament injuries, but the current data have confirmed that for multiple ligament injuries, the near- to mid-term efficacy of reconstruction with autologous tissue is comparable to that of reconstruction with allogeneic tissue.6 Lawhom et al. reported that reconstruction of the anterior cruciate ligament using either autologous tissue grafts or allogenic patellar tendon grafts with a 2-year follow-up resulted in no significant differences between the two groups in terms of total scores, laxity, and subjective evaluation were not significantly different between the two groups, and the efficacy was favorable [12]. In conclusion, arthroscopic application of allogeneic tibialis anterior tendon graft to reconstruct anterior and posterior cruciate ligament injuries of the knee joint avoids the sequelae and complications of autologous tendon graft harvesting, shortens the surgical time, has a reliable efficacy, and is conducive to the postoperative rehabilitation and exercise, which is a feasible measure for the treatment of multiple ligament injuries of the knee joint. However, it may still have potential rejection reactions and infectious diseases, thus it is necessary to strengthen the management of allogeneic tendon tissue bank and long-term follow-up of its graft repair and reconstruction of multiple ligament injuries of the knee joint in multiple cases to summarize the efficacy of the work.