Osteoprotegerin/bone morphogenetic protein 2 combining with collagen sponges on tendon-bone healing in rabbits.

INTRODUCTION: The aim was to investigate the effect of collagen sponges (CS) as a delivery device for osteoprotegerin (OPG)/bone morphogenetic protein 2 (BMP-2) and support matrix on the tendon-bone healing after anterior crusicate ligament (ACL) reconstruction in modeled rabbits. MATERIALS AND METHODS: Sixty New Zealand white rabbits were randomly divided into four groups based on treatments they received at the tendon-bone interface after left knee ACL reconstruction: the control group, OPG/BMP-2, CS, and OPG/BMP-2/CS combination. At 4, 8 and 12 weeks post-surgery, five rabbits from each group were euthanized to examine the tendon-bone healing. Levels of OPG and BMP-2 in synovial fluid, the bone tunnel enlargement value, the histomorphological typing of tendon-bone interface, and the bone tunnel area of the tendon-bone interface were compared among different treatments. RESULTS: The OPG/BMP-2/CS combination treatment group had the highest levels of OPG and BMP-2 in synovial fluid (both P < 0.05), the greatest number of Sharpey-like collagen fibers at all test points (P < 0.05), the most fibrocartilage enthesis on week 12, the greatest bone tunnel area (P < 0.05), and the greatest decrease in bone tunnel enlargement on week 12 (P < 0.05). Histomorphological typing of tendon-bone interface of all groups showed changes varying from tendon-bone separation to firm healing, and the change was most significant in the OPG/BMP-2/CS combination treatment group. CONCLUSION: CS treatment alone serves as a fixing support, and CS combining with growth factors OPG/BMP-2 ensures slow and stable release of OPG/BMP-2, significantly improves the tendon-bone healing in the rabbit ACL model.

[Comparative analysis of two hybrid technique in treating multilevel cervical spondylotic myelopathy via anterior approach].

OBJECTIVE: To compare the clinical effects and complications of two hybrid decompression techniques in treating multilevel (>=3) cervical spondylotic myelopathy(MCSM). METHODS: The clinical data of 124 patients with multilevel (>=3) cervical spondylotic myelopathy treated by surgery and follow-up from January 2008 to December 2016 were retrospectively analyzed. According to the different operative methods, the patients were divided into group A and group B. Anterior cervical discectomy and fusion (ACDF) combined with anterior cervical corpectomy and fusion with preserved posterior vertebral wall (PWCF) were performed in group A; ACDF combined with anterior cervical corpectomy and fusion(ACCF) were performed in group B. There were 44 males and 16 females in group A with an average age of (60.43±7.52) years old, 46 males and 18 females in group B with an average age of (61.61±6.39) years old. No significant differences were found in gender, age between two groups. The operative time, intraoperative blood loss, hospital stay, rate of complications, postoperative Japanese Orthopaedic Association (JOA) score and improvement of cervical curvature were compared between two groups. RESULTS: All the operations were successful. The follow-up time was 13 to 28(23.0±12.1) months in group A and 12 to 30(24.0±11.5) months in group B. The operative time, intraoperative blood loss, hospital stay in group B were higher than those in group A(P<0.05). A total of 37 patients occurred complications, including 14 cases in group A and 23 cases in group B. The incidence of complications was 23.33%(14/60) in group A and 35.94%(23/64) in group B. The incidence of complications in group B was significantly higher than that in group A(P<0.05). Postoperative JOA scores were significantly improved (P<0.01), there was no significant difference between two groups (P>0.05). The physiological curvature of cervical vertebra was improved significantly after operation, and there was no significant difference between two groups(P>0.05). CONCLUSIONS: Both surgical methods can obtain satisfactory clinical efficacy for multilevel(>=3) cervical spondylotic myelopathy, but compare with group B (ACDF combined with ACCF), group A (ACDF combined with PWCF) has shorter operation time, less trauma, less bleeding, and lower incidence of complications. ACDF combined with PWCF can be preferentially selected for the patients who corresponding to the indications.