Objective To study the cl inical outcomes of Numelock II polyaxial system in treatment of type C fractures of the distal radius. Methods From March 2006 to June 2007, 12 cases of type C distal radial fractures (6 males and 6 females)were treated with open reduction and internal fixation. The mean age of the patients was 48.2 years (34-64 years)．The locations were left wrist in 5 cases and right wrist in 7 cases, including 1 case of old fracture and 11 cases of fresh fractures. All fractures were closed. The mean course of disease was 9 days and 7 hours (4 hours to 60 days). According to AO/ASIF classification, there were 4 cases of C1 type, 5 cases of C2 type and 3 cases of C3 type. Preoperatively, the palmar tilt angle was —30° to 30° (— 5° on average), and the radial inclination angle was 5° to 13° (7.7° on average), and the radial shortening was 5 mm to 15 mm (9 mm on average). One case combined with dislocation of elbow joint and 2 cases combined with multi ple injuries. Results All incision healed by first intention. Postoperative follow-up ranged from 14 months to 29 months (15.6 months on average). The X-ray films showed that the union of fractures was achieved 6-8 weeks (6.6 weeks on average). No screws breakage occurred. The articular facets weresmooth in 11 of 12 patients. After operation, the palmar tilt angle was 0° to 15° (6.7° on average), and the radial inclination angle was 5° to 15° (10.2° on average), showing significant differences when compared with those before operation (P lt; 0.05). All the radial shortening was corrected. The ROM of the wrist was 55%-100% of the normal side. The grip strength was 55%-90% of the normal side. The results were excellent in 9 cases, good in 2 cases, and poor in 1 cases by X-ray film and wrist function assessment, the excellent and good rate was 91.7%. Conclusion Numelock II polyaxial system fixation is an ideal method to treat type C fractures of the distal radius. Numelock II polyaxial mechanism may provide the free adjustabil ity of screw trajectories and a higher degree of overall stabil ity compared to monoaxial locking plates.
Objective To study the difference of repairing segmental bone defect with bio-derived bone preserved by various methods.Methods Freeze-dried biomaterials had been stored in two different preservation solutions for three months,while the biomaterials stored for same period were observed as control group. The experimental model of 15 mm radial segmentaldefect was made in 60 New Zealand white rabbits, which were divided into groups A,B and C according to transplant materials preserved by various methods. Groups A and B were deeply divided into A1 and A2 subgroups, B1 and B2 subgroups according to whether materials were cocultured with osteoblasts. Tissue engineered bone was used to repair bone defects of left limbs in A1 and B1 subgroups, while simple material to repair defects of right limbs in A2 and B2 subgroups. Group C was divided into C1 and C2 subgroups. Freeze-dried material was used to repairbone defects of the left limbs, while defects of the right limbs as blank control group. The samples were harvested and observed by the roentgenographical, histomorphological, biomechanical and computerized graphical analysis at 4,8 and 16 weeks. Results All of the defects treated with implants exhibited new bone formation 4, 8 and 16 weeks postoperatively, increasing with time. The radiological, histomorphological and biomechanical evaluation showed that the ability of new bone formation was arranged in 6 subgroups as follows:A1gt;A2gt;C1gt;B1gt;B2gt;C2, the difference was significant between them (P＜0.001, P＜0.05).The ability of new bone formation was best and at 16 weeks the defect was bridged with the appearance of marrow cavities in A1 subgroup, the biomechanicalproperties in implants approached to those of normal bone. Conclusion The choice of proper preservation solution can improve the ability of repairing bone defect.
ObjectiveTo introduce a new bone defect model based on the anatomical measurement of radius and ulna in rabbits for offering a standard model for further tissue engineering research. MethodsFifteen healthy 4-month-old New Zealand rabbits were selected for anatomic measurement and radiological measurement of the radius and ulna. Another 30 healthy 4-month-old New Zealand rabbits were randomly divided into groups A, B, and C (n=10). The radius bone defect was created bilaterally in 3 groups. In group A, the periosteum and interosseous membranes were fully removed with jig-saw by approach between extensor carpi radialis muscle and musculus extensor digitorum. The periosteum and interosseous membranes were fully removed in group B, and only periosteum was removed in group C with electric-saw by approach between extensor carpi radialis muscle and flexor digitorum profundus based on anatomical analysis results of ulnar and radial measurement. The gross observation, X-ray, micro-CT three-dimensional reconstruction, bone mineral density (BMD), and bone mineral content (BMC) were observed and recorded at immediate and 15 weeks after operation. HE staining and Masson staining were performed to observe bone formation in the defect areas. ResultsBlood vessel injury (1 rabbit), tendon injury (2 rabbits), postoperative hematoma (1 rabbit), and infection (1 rabbit) occurred in group A, postoperative infection (1 rabbit) in group C, and no postoperative complications in group B; the complication rate of group A (50%) was significantly higher than that of groups B (0%) and C (10%) (P<0.05). The radiological examination showed bone defects were fully repaired in groups A and B at 15 weeks, but bridging callus formation was observed in group C. There was no significant difference in BMC and BMD among 3 groups (P>0.05). HE staining and Masson staining results showed bone formation in group A, with structure disturbance and sclerosis. New bone formed in groups B and C, cartilage cells were observed in the center of bone cells. ConclusionThe radius bone defect model established by approach between extensor carpi radialis muscle and flexor digitorum profundus is an ideal model because of better exposures, less intra-operative blood loss, less complications. Interosseous membranes play a role in bone tissue repair process, and the mechanism needs further study.
Objective To explore the application of improved carpal shoot through view (ICSTV) method in the treatment of distal radius fractures with volar plate internal fixation. Methods The clinical data of 67 patients with distal radius fractures who met the selection criteria between January 2020 and January 2023 was retrospectively analyzed. There were 30 males and 37 females with an average age of 53.6 years (range, 18-75 years). According to the AO/Orthopaedic Trauma Association (AO/OTA) classification, there were 25 cases of type B and 42 cases of type C. The time from injury to operation ranged from 2 to 6 days, with an average of 3.8 days. During the operation, bilateral cortical drilling was performed, and the length of the implanted screw was 1-2 mm shorter than that measured by the depth ruler. Standard anteroposterior and lateral (AAL) fluoroscopy and ICSTV fluoroscopy were performed after volar anatomic locking plate fixation, respectively. If the dorsal cortex of the distal radius was detected to be penetrated, the short screw was replaced and ICSTV fluoroscopy was performed again until no screw was penetrated. The detection rate of dorsal cortical screw penetration was compared between AAL fluoroscopy and ICSTV fluoroscopy. Postoperative CT scan was performed to confirm the presence or absence of dorsal cortical screw penetration. Results Intraoperative AAL fluoroscopy found 5 screws penetrating the dorsal cortex in 4 patients (6.0%), and ICSTV fluoroscopy found 19 screws penetrating the dorsal cortex in 15 patients (22.4%) including the above 4 patients, with a significant difference in the detection rate between the two fluoroscopy methods [OR=0.267 (0.084, 0.845), P=0.018]; 15 patients were replaced with short screws during operation. At the same time, ICSTV fluoroscopy detected 2 screws penetrating into the distal radioulnar joint in 2 cases (3.0%), which could not be found in AAL fluoroscopy, and the direction of the screws was adjusted and replaced. All patients were reexamined by wrist CT within 3 days after operation, and no dorsal cortical screw penetration or screw penetration into the distal radioulnar joint was found. All the 67 patients were followed up 6-18 months, with an average of 11.3 months. Extensor tendon irritation occurred in 2 patients at 3 months after operation, and no extensor tendon rupture occurred in all patients during follow-up. All fractures healed well, and the healing time was 8-13 weeks, with an average of 10.8 weeks. There was no complication such as internal fixation loosening or fracture displacement. The Gartland-Werley score at last follow-up ranged from 0 to 15, with an average of 5.6. ConclusionICSTV fluoroscopy can effectively detect occult dorsal cortical screw penetration of the distal radius that can not be revealed by AAL fluoroscopy.