Mandibular fracture healing is a complex process involving nerves and growth factors. Nerve growth factor (NGF) not only facilitates the maintenance of sympathetic neurite growth but also stimulates other growth factors that can promote the essential osteogenesis and angiogenesis for fracture healing. Therefore, it is necessary to analyze the combined effects of NGF, bone morphogenic protein-9 (BMP-9), and vascular endothelial growth factor (VEGF) to accelerate the healing of mandible fractures. The models of mandible fracture with local nerve injury established in 48 rabbits were randomly divided into nerve growth factor group (NGF group), gelatin sponge group (GS group), blank group, and intact group. The recovery of nerve reflex was assessed by observing the number of rabbits with lower lip responses to acupuncture. The fracture healing was observed with visual and CBCT, and then callus tissues from the mandibular fracture area were collected for hematoxylin and eosin (HE) staining observation, and the expression of BMP-9 and VEGF in callus at different stages was detected by quantitative real-time PCR (qRT-PCR). Needling reaction in the lower lip showed the number of animals with nerve reflex recovery was significantly higher in the NGF group than that in the GS and blank groups at the 2nd and 4th weeks after the operation. The combined results of macroscopic observation, CBCT examination, and histological analysis showed that a large number of osteoblasts and some vascular endothelial cells were found around the trabecular bone in the NGF group and the amount of callus formation and reconstruction was better than that in the GS group at the 2nd week after the operation. The qRT-PCR results indicated that the expression levels of BMP-9 and VEGF in the four groups reached the highest values at the 2nd week, while the expression levels of both in the NGF group were significantly higher than that in the GS group. The exogenous NGF could accelerate the healing of mandible fractures. This work will provide a new foundation and theoretical basis for clarifying the mechanism of fracture healing, thereby promoting fracture healing and reducing the disability rate of patients.

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Effects of exogenous nerve growth factor on the expression of BMP-9 and VEGF in the healing of rabbit mandible fracture with local nerve injury.

Anteromedial cortical support apposition (positive and/or neutral cortical relations) is crucial for surgical stability reconstruction in the treatment of trochanteric femur fractures. However, the loss of fracture reduction is frequent in follow-ups after cephalomedullary nail fixation. This paper aimed to investigate the possible predictive risk factors for postoperative loss of anteromedial cortex buttress after nail fixation.A retrospective analysis of 122 patients with AO/OTA 31A1 and A2 trochanteric femur fractures treated with cephalomedullary nails between January 2017 and December 2019 was performed. The patients were classified into two groups according to the postoperative status of the anteromedial cortical apposition in 3D CT images: Group 1 with contact "yes" (positive or anatomic) and Group 2 with contact "No" (negative, loss of contact). The fracture reduction quality score, tip-apex distance (TAD), calcar-referenced TAD (Cal-TAD), Parker ratio, neck-shaft angle (NSA), and the filling ratio of the distal nail segment to medullary canal diameter in anteroposterior (AP) and lateral fluoroscopies (taken immediately after the operation) were examined in univariate and multivariate analyses. Mechanical complications were measured and compared in follow-up radiographs.According to the postoperative 3D CT, 84 individuals (69%) were categorized into Group 1, and 38 individuals (31%) were classified as Group 2. The multivariate logistic regression analysis showed that the poor fracture reduction quality score (P < 0.001) and decreasing filling ratio in the lateral view (P < 0.001) were significant risk factors for the loss of anteromedial cortical contact. The threshold value for the distal nail filling ratio in lateral fluoroscopy predicting fracture reduction re-displacement was found to be 53%, with 89.3% sensitivity and 78.9% specificity. The mechanical complication (varus and over lateral sliding) rate was higher in Group 2.The fracture reduction quality score and the decreasing filling ratio of the distal nail to the medullary canal in the lateral view (a novel parameter causing pendulum-like movement of the nail) were possible risk factors for postoperative loss of anteromedial cortical support. 

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Low filling ratio of the distal nail segment to the medullary canal is a risk factor for loss of anteromedial cortical support: a case control study

Review of immunological plasma markers for longitudinal analysis of inflammation and infection in rat models

Restoration of ambulatory status is considered a primary treatment goal for older patients with intertrochanteric fractures. Several surgical-related parameters were reported to be associated with mechanical failure without focusing on the functional outcomes. Our study examines the roles of both clinical and surgical parameters as prognostic factors on 1-year postoperative ambulatory outcomes, reaching a good functional outcome (the New Mobility Score: NMS ≥ 5) and returning to preinjury functional status at one year, of older patients with intertrochanteric fracture. Intertrochanteric fractures patients age ≥65 years who underwent surgical treatment at our institute between January 2017 and February 2020 were included. Of 209 patients included, 149 (71.3%) showed a good functional outcome at one year. The pre-injury ambulatory status (OR 52.72, 95%CI 5.19–535.77, p = 0.001), BMI <23 kg/m2 (OR 3.14, 95%CI 1.21–8.13, p = 0.018), Hb ≥10 g/dL (OR 3.26, 95%CI 1.11–9.57, p = 0.031), and NMS at discharge ≥2 (OR 8.50, 95%CI 3.33–21.70, p < 0.001) were identified as independent predictors for reaching a good postoperative functional outcome. Only aged ≤80 (OR 2.34, 95%CI 1.11–4.93, p = 0.025) and NMS at discharge ≥2 (OR 6.27, 95%CI 2.75–14.32, p < 0.001) were significantly associated with an ability to return to preinjury function. To improve postoperative ambulatory status, orthopedic surgeons should focus more on modifying factors, such as maintaining the preoperative hemoglobin ≥10 g/dL and providing adequate postoperative ambulation training to maximize the patients’ capability upon discharge. While surgical parameters were not identified as predictors, they can still be used as guidance to optimize the operation quality.

Prognostic Factors of 1-Year Postoperative Functional Outcomes of Older Patients with Intertrochanteric Fractures in Thailand: A Retrospective Cohort Study.

Intra-medullary devices are the most common mode of fixation of inter-trochanteric fractures. Short proximal femur nails (PFN) used for fixing these fractures, unlike the long nails, are non-anatomic and are usually straight with no curvature in antero-posterior plane. As a result, there is always a chance of the nail tip impinging against the anterior cortex of femur.A total of 80 patients with trochanteric fractures (AO 31A2 and 31A3), operated with short PFN, were followed up retrospectively and prospectively from 2019 to 2021, for a period of 6 months. All fractures were fixed with PFNs, with nails ranging from 170 to 250 mm. Radiological analysis was done on hip lateral X-rays (taken at 6 months) using Angle at Distant Axis (ADA) and Nail Tip Position (NTP). Functional outcome analysis was done using Harris Hip Score. Patients were graded into 2 groups according to ADA (ADA>4° and ADA<4°). Incidence of anterior thigh pain was noted in patients on follow up and was statistically evaluated with nail size, nail diameter, ADA and NTP.Mean ADA was 4.19° ± 1.45; mean NTP grade was 1.98 ± 1.11. Mean nail size was 201.87 mm with a mean nail diameter of 9.76 mm. Twenty patients complained of anterior thigh pain on follow-up. Twenty-five patients had NTP grade 3 or above of which 16 complained of anterior thigh pain (p < 0.001). Fifty-five patients had nail diameter of 10 mm or above of which 14 had anterior thigh pain (p < 0.01). Fifty-three patients had a nail length of 200 mm or above of which 16 patients complained of thigh pain on follow up (p < 0.01).There is a mismatch of short PFNs with anterior bow of femur. Use of shorter nails with narrow diameters will avoid this mismatch to an extent. 

Mismatch of short straight proximal femur nails with anterior bow of femur in Indian population- A radiological and functional analysis.

Positive or negative anteromedial cortical support of unstable pertrochanteric femoral fractures: A finite element analysis study.

Discussion on bone healing rate and expression of cytokines and growth factors in rat models with simple fracture and brain injury

Ulnar head fractures are increasingly higher with the growing proportion of the elderly people. Failure to achieve a stable anatomic reduction of ulna head fracture may lead to a distal radioulnar joint (DRUJ) dysfunction and nonunion of the distal radius. Due to the lack of the postoperative reporting outcomes and the biomechanical studies, it has not been well established about the optimal management of the comminuted distal ulna head fracture. Hence, the purpose of this study is to use finite element analysis to explain the advantages and disadvantages of ulnar-side locking plate fixation compared with dorsal-side locking plate fixation and its screw arrangement in the treatment of ulnar head fractures. FE models of the ulnar head fracture and the models of ulnar-side locking plate and dorsal-side plate with two or three distal screws was constructed. In order to simulate forces acting on the ulnar and the osteosynthesis material during daily-life activity in subjects who underwent reconstructive surgery, we applied three loading conditions to each model, viz. 20 N axial compression, 50 N axial compression, 1 N∙m torsion moment, 1 N∙m lateral bending moments, and 1 N∙m extension bending moments. Under these conditions, values of the von Mises stress (VMS) distribution of the implant, peak VMS, the relative displacement of the head and shaft fragments between the fracture ends and the displacement and its direction of the models were investigated. The stress values of ulnar-side plates were lower than those of dorsal-side plates. And the ulnar-plate fixation system also has smaller maximum displacement and relative displacement. When adding a screw in the middle hole of the ulnar head, the values of model displacement and the peak stress in fixation system are lower, but it may evidently concentrate the stress on the middle screw. In conclusion, our study indicated that ulnar-side locking plates resulted in a lower stress distribution in the plate and better stability than dorsal-side locking plates for ulnar head fracture fixation. Adding an additional screw to the ulnar head could increase the stability of the fixation system and provide an anti-torsion function. This study requires clinical confirmation of its practicality in the treatment of ulnar head fractures. This study requires clinical confirmation as to its practicality in the treatment of ulnar head fracture.

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Chensong Yang

Papers

Positive or negative anteromedial cortical support of unstable pertrochanteric femoral fractures: A finite element analysis study.

Discussion on bone healing rate and expression of cytokines and growth factors in rat models with simple fracture and brain injury

Finite element analysis of different locking plate fixation methods for the treatment of ulnar head fracture.