BACKGROUND:Intermittent negative pressure has been proven to promote the repairing of soft tissue and bone healing, but the effect of negative pressure on the tendon-bone healing after anterior cruciate ligament reconstruction has not been reported.
OBJECTIVE:To research the effect of intermittent negative pressure on tendon-bone healing after anterior cruciate ligament reconstruction and on the biomechanics of tendon grafts.
METHODS:A total of 24 New Zealand white rabbits were randomly selected to establish the models of anterior cruciate ligament reconstruction of autogenous semitendinosus. The hind leg of one side was selected randomly as the negative pressure group, and the joint of the negative pressure side was connected with the micro-negative pressure aspirator through drainage tube and maintained a low-intensity and intermittent negative pressure;the contralateral hind leg was as the control and connected with ordinary drainage tube. Drainage tubes of both sides were removed at the same time after 5 days. At 6 weeks after modeling, the joint fluid was drawn to detect the expression levels of interleukin-1β;femur-ligament-tibia complex was used for tension measurement of tendon graft, and histological observation of tendon-bone interface.
RESULTS AND CONCLUSION:One rabbit had joint infection, and final y 23 rabbits were included in the study. Tension measurement results showed that maximum load for breakage in negative group pressure was significantly greater than that in the control group (P<0.05). Histological observation found that the number of osteoblasts in the negative pressure group was significantly more than that in the control group, and the difference was statistical y significant (P<0.01). Detection of synovial fluid showed that iterleukin-1βcontent in synovial fluid of the negative pressure group was lower than that in the control group, and the difference was statistical y significant (P<0.01). Intermittent negative pressure may play an active role in tendon-bone healing and modeling of tendon graft after anterior cruciate ligament reconstruction.

BACKGROUND: Ulnar coronoid process has special anatomy and it is adjacent to vascular nerve. It is characterized by weak fixation, unstable recurrence, postoperative elbow joint stiffness and pain. These make the treatment of ulnar coronoid process fracture, in particular in complex elbow joint injuries, challenged. OBJECTIVE: To investigate the efficacy of internal fixation with steel plate through an anterior approach on ulnar coronoid process Regan-Morrey type II or type III fracture in complex elbow injury METHODS: Sixteen patients with complex elbow injury and ulnar coronoid process fractures who underwent open reduction and internal fixation were followed up between September 2012 and May 2017. Among these patients, 11 patients had Regan-Morrey type II fracture, 5 patients had Regan-Morrey type III fracture, 14 patients had humeral head fracture, and 2 patients had ulnar olecranon fracture. All patients provided written informed consent. This study was approved by the Medical Ethics Committee of Hong Hui Hospital, China. Ulnar coronoid process fractures were reduced and fixed with steel plate through the space between the median nerve and the radial artery using an anterior approach. At the same time, all radial humeral head and olecranon fractures were treated by internal fixation. RESULTS AND CONCLUSION: All patients acquired acceptable reduction and firm fixation of fractured fragments. All of them were followed up for 13-28 months. At the final follow-up, solid osseous union was confirmed for all coronoid fractures. The average time to radiologic union was 16.5 weeks. The mean flexion-extension arc was 113.4°, the flexion contracture was 13.8°, and further flexion was 127.2°. The mean pronation arc was 72.5°. The mean supination arc was 74.7°, and the mean forearm rotation arc was 146.9°. 11 patients achieved functional arc of motion. All patients were satisfied with the treatment with the mean Mayo Elbow Performance score of 90.3 points. 11 patients achieved excellent elbow performance and 5 patients achieved good elbow performance. These results suggest that ulnar coronoid process fractures in complex elbow injury can be treated successfully with an anterior surgical approach. This approach allows for accurate and rigid internal fixation with steel plate and early functional exercise, resulting in a reasonable outcome.