BACKGROUND: Current research of mechano growth factor (MGF) mainly focuses on the muscles and nerve damage and repair, and it has bean confirmed that MGF can promote muscle cell hypertrophy and nerve repair significantly. Regarding its role in fracture healing is unclear. OBJECTIVE: To investigate the effect of MGF on radial fracture healing in rabbits. METHODS: By using random digital table method, 12 New Zealand rabbits were divided into 3 groups: blank control group, low-dose MGF group and high-dose MGF group. The models with 5 mm bone defect were produced in the middle of the left radius in rabbits. At 3 days after the surgical operation, the defective areas were given 0.2 mL PBS or 0.2 mL MGF (0.36 and 0.72 g/L) injected into the ends of fracture areas, respectively, once per day for continuous 5 days. At 4, 6, 8 weeks after operation, X-ray photography was used to evaluate the healing of fracture, and the histological examinations were performed at the 8~(th) weak to observe the call morphology at the fracture lesion. RESULTS AND CONCLUSION: At 1 day after operation, the activities of rabbits were reduced, with slightly reduced food intake, at 2 days they almost recovered to normal activities and diet. At 3 days, the surgical incision slightly swelled with a small amount of bleeding and without obvious signs of infection. All 12 rabbits entered the final analysis. X-rays showed that two fracture ends have basically combined in the high-dose MGF group at 4 weeks post-surgery, cortical bone was continuous and fracture lines were unclear. At 6 weaks the bone medullary cavity almost run through and fully run through at 8 weeks. The healing time in the high-dose MGF group was remarkably shorter than that in blank control group and low-dose MGF group, the healing was in high quality. At 8 weeks after operation, a large number of osteoid tissues were observed in the blank control group, a small amount of woven bone formed, at a transition period from the fibrous bone callus to the bony bone callus; a large number of woven bone formed inthe low-dose MGF group, at bony bone callus period; in the high-dose MGF group, a large number of woven bones converted into mature lamellar bone, at the callus rebuilding phase, which was consistent with imaging results. It is indicated that MGF can accelerate fracture healing significantly in a rabbit model and shows a dose-dependent manner in a certain range.

Objective:To delineate the morphological features of pedicle-facet joints in lumbar spondylolysis patients, correlating these with spinopelvic parameters to explore their mechanisms and clinical implications.Methods:This study enrolled 121 patients with L 5 spondylolysis (IS group), 108 with L 4, 5 degenerative spondylolisthesis (DS group), and 100 with normal L 4, 5 but L 5S 1 lumbar disc herniation (NL group), who underwent radiography and multislice spiral CT from May 2020 to January 2023. Parameters including vertebral slip percentage (SP) and spinopelvic alignments, such as sacral slope and lumbar lordosis, were quantified using standing lateral lumbar radiographs. Morphological parameters of the L 4 and L 5 facet joints were measured on 3D reconstructed lumbar CT images, including the facet joint angle (FJA), pedicle-facet joint angle (PFA), facet joint osteoarthritis (OA), and facet joint tropism (FT). Results:The analysis revealed significant variances in SS and LL among the groups ( F=21.910, P<0.001; F=22.439, P<0.001). The IS group exhibited the highest SS and LL, followed by the DS and NL groups. Morphological assessments showed the largest L 4 FJA in the IS group, with progressive decreases in the DS and NL groups ( F=344.791, P<0.001). Conversely, L 4 PFA was greatest in the DS group ( F=193.725, P<0.001). Notably, L 4 OA was markedly more severe in the DS group compared to IS and NL groups ( H=467.925, P<0.001), with no significant disparity between IS and NL groups ( P>0.05). Correlation analyses within each cohort highlighted a negative association of sacral slope and lumbar lordosis with facet joint angles, yet a positive correlation with pedicle-facet joint angles both with statistical significance ( P<0.05). Furthermore, L 4 facet joint angles were consistently smaller than those at L 5, and L 4 pedicle-facet joint angles were larger than L 5 ( P<0.05). Osteoarthritis at L 5 was more pronounced in the IS group compared to L 4 ( Z=7.043, P<0.001), a trend inversely observed in the DS group ( Z=11.868, P<0.001), while the NL group showed no significant osteoarthritic variance between levels ( Z=0.556, P=0.578). Conclusion:Patients with lumbar spondylolysis demonstrate elevated sacral slope and lumbar lordosis, indicative of increased localized biomechanical stress in the lumbar spine. These alterations in the morphology of the pedicle-facet joints highlight the distinctive structural adaptations and potential strain distributions within this cohort.

Objective:To observe the morphological characteristics of L 4, 5 facet joints in patients with degenerative lumbar spondylolisthesis (DLS) of different spinopelvic types based on Roussouly classification. Methods:We retrospectively analyzed 142 patients with DLS who visited the department of orthopaedics in the Affiliated Hospital of Southwest Medical University from August 2018 to May 2022. There were 33 males aged 65.0±10.7 years and 109 females aged 61.8±9.6 years. The following morphological parameters of the L 4, 5 facet joint were measured on the CT images: facet joint angle (FJA), pedicle facet angle (PFA), facet joint tropism (FT) and facet joint osteoarthritis (OA) degree; the sacral slope (SS), lumbar lordosis (LL) and percentage of L 4 slip distance (SDP) were measured on preoperative standing neutral lumbar radiographs. According to the Roussouly classification, the patients were divided into four groups (type I, type II, type III, and type IV). The differences of morphological parameters of the facet joints and SDP were compared among the four groups, and the correlation between the FJA and PFA was analyzed. Results:There were 142 patients, including 28 type I, 50 type II, 43 type III, and 21 type IV according to the Roussouly classification. The SDPs of type I, type II, type III, and type IV were 19.1%±3.4%, 18.6%±3.9%, 21.7%±3.9%, 25.0%±2.4%, respectively. Except for types I and II, there were statistically significant differences in pairwise comparison among all other types ( P<0.05). The FJAs in type I and type II (31.4°±6.3°, 35.2°±6.8°) were larger than those in type III (28.4°±5.6°) and type IV (23.4°±4.5°), and the FJA in type III was larger than that in type IV. Conversely, the FJA in type I was smaller than that in type II. These differences were statistically significant ( P<0.05). The PFAs in type I and type II (113.9°±4.9°, 111.3°±5.6°) were smaller than those in type III (116.3°±4.4°) and type IV (121.8°±3.5°), and the PFA in type III was smaller than that in type IV, while, the PFA in type I was larger than that in type II. These differences were statistically significant ( P<0.05). The degree of OA in both type I and type II was lower than that in type III and type IV, with statistically significant differences ( P<0.05). However, there were no statistically significant differences in the degree of OA between type I and type II and between type III and type IV ( P> 0.05). Additionally, there were no statistically significant differences ( F=0.40, P=0.752) in the FT values among type I, type II, type III, and type IV (5.8°±2.3°, 5.6°±2.4°, 6.1°±1.8°, 5.9°±1.9°). Pearson correlation analysis showed that FJA was negatively correlated with PFA ( r=-0.68, P<0.001). Conclusion:In the slip segment of DLS, the facet joint morphology was part of the joint configuration in different spinopelvic types, not just the result of joint remodeling after DLS. Morphological characteristics of the facet joints and DLS interacted with each other.

BACKGROUND:Hyperuricemia is a common metabolic disease,and the main clinical manifestation of patients with hyperuricemia is the formation of uric acid crystals leading to gout.Previous studies have only reported that uric acid crystals lead to intervertebral disc degeneration,but there are fewer studies on the correlation between hyperuricemia and intervertebral disc degeneration. OBJECTIVE:To retrospectively analyze the characteristics of intervertebral disc degeneration in patients with hyperuricemia and the correlation between serum uric acid level and intervertebral disc degeneration. METHODS:A retrospective analysis was performed in all patients diagnosed with intervertebral disc degeneration admitted at the Department of Orthopedics,the Affiliated Hospital of Southwest Medical University from January 2021 to December 2022.There were 97 hyperuricemia patients in the hyperuricemia group and 194 non-hyperuricemia patients in the control group according to sex and age in a ratio of 1:2.Blood uric acid test results were collected,and Pfirrmann scoring was performed for the degree of disc degeneration in patients based on the whole spinal MRI images.The difference in the degree of disc degeneration between the two groups was compared,and the correlation between the serum uric acid level and the degree of intervertebral disc degeneration was analyzed. RESULTS AND CONCLUSION:The Pfirrmann score in the hyperuricemia group was higher than that in the control group,and the total number of disc degeneration in the hyperuricemia group was also significantly higher than that in the control group(P<0.05).Spearman correlation analysis showed that the degree of disc degeneration in male patients was positively correlated with serum uric acid level at many spinal segments in the hyperuricemia group(C3/4:r=0.317,C4/5:r=0.333,C5/6:r=0.309,L2/3:r=0.443,P<0.05);the degree of disc degeneration in female patients was also positively correlated with serum uric acid level(C3/4:r=0.354,C4/5:r=0.388,C6/7:r=0.312,T7/8:r=0.282,T9/10:r=0.305,T11/12:r=0.277,L4/5:r=0.319,L5-S1:r=0.367,P<0.05).In the control group,there was no significant correlation between the degree of disc degeneration and serum uric acid level in male and female patients(P>0.05).To conclude,in patients with hyperuricemia,the higher serum uric acid level indicates the more serious intervertebral disc degeneration.Therefore,hyperuricemia is one of the risk factors for intervertebral disc degeneration.