Clinical results of arthroscopic anterior cruciate ligament reconstruction with short femoral tunnel / 中国骨伤

OBJECTIVE@#To evaluate the clinical outcome of arthroscopic reconstruction of anterior cruciate ligament (ACL) with short femoral tunnel.@*METHODS@#From May 2013 to June 2017, 128 patients with anterior cruciate ligament reconstruction were performed with Transportal technique. Among them, 32 cases had short femoral tunnel were included, including 13 males and 19 females, aged 25.8 (17 to 43) years old, with a mean history of (4.5±1.1) months. The tibial tunnels were drilled in the middle of the footprint of the ACL, and femoral tunnels were drilled by transportal technique. Grafts were fixed with Endobutton at the femoral side and with interference screw at the tibial side. The changes of symptoms and signs were observed and the anterior tibial displacement was measured. The function of knee joint was evaluated by Lysholm score and Tegner score.@*RESULTS@#All patients were followed up for over 2 years. At the latest follow-up, 30 patients were negative and 2 patients were positive in knee shift test; 28 patients were negative in Lachman sign, 4 patients were positive in degree I; 30 patients were negative in anterior drawer test, 1 patient was positive in degree I and 1 patient was positive in degree II. The anterior displacement of the tibia increased by (2.6±1.8) mm compared with the healthy side, which was significantly different from that before operation (=19.77, <0.05). Lysholm score of 82.2±6.1 was significantly higher than that before operation (=17.33, =0.001). According to Lysholm score evaluation, 15 cases got an excellent result, 10 were good, 7 were fair, and no bad results, with a significant difference compared with that before operation (=-7.151, <0.05). Tegner motor function score of (7.4±0.6) was significantly different from that before operation (=9.11, =0.000 5). After operation, the knee joint movement ability of the patients improved significantly. Twelve patients could participate in antagonistic sports and 15 patients could participate in non-antagonistic sports. Fifteen patients were very satisfied with the curative effect, 13 patients were satisfied with the curative effect.@*CONCLUSIONS@#The incidence of short femoral tunnel in anterior cruciate ligament reconstruction with transportal technique is 25%. At present, the clinical effect of patients with short tunnel is acceptable. However, due to the lack of comparative study, the effect of short tunnel on the curative effect is still unclear.

In vivo experimental study on MAO-ZK60 magnesium alloy bio-safety and degradation / 中国骨伤

<p><b>OBJECTIVE</b>To investigate the tissue toxicity and degradation of ZK60 magnesium alloy with micro-arc oxidation coatings (MAO-ZK60), in order to discuss the possibility of its potential application for orthopedic implantation.</p><p><b>METHODS</b>Eighteen Sprague-Dawley rats were randomized equally to three groups of A, B, C. MAO-ZK60 sticks were implanted in the femoral condyles of rats in group A (experimental group). Sticks of ZK60 magnesium alloy without any surface treatment (ZK60) were implanted in the femoral condyles of rats in group B (control group). The poly L-lactic acid (PLLA) sticks were implanted in the femoral condyles of rats in group C (control group). The changes of blood bio-chemical indexes of different groups were observed and compared. All the rats were sacrificed at 12 weeks and histological observation of liver and kidney were carried out to evaluate the hepatic and renal toxicity. Micro-CT was used to evaluate the degradation of the implants and to observe the bone-implant interface. GEHC MicroView software was operated to calculate the volume variation of magnesium alloy.</p><p><b>RESULTS</b>There was no apparent biochemical index change with time in each group, and there was no significant change among each group. No significant pathology change of liver and kidney was detected among three groups. By using a micro-CT, a gap was found on the bone-implant interface at 4 weeks after implantation in group A, which decreased gradually at 8 weeks after implantation and continued to decrease at 12 weeks after implantation. A good combination between bone and implant formed at 12 weeks after implantation. Group A has less change of volume with time than group B (P < 0.05).</p><p><b>CONCLUSION</b>ZK60 magnesium alloy with micro-arc oxidation coatings is safe in vivo. It has higher corrosion resistance than ZK60 magnesium alloy without any surface treatment.</p>