Intermittent vibrations accelerate fracture healing in sheep

Abstract Purpose: To investigate the effect of intermittent vibration at different intervals on bone fracture healing and optimize the vibration interval. Methods: Ninety sheep were randomized to receive no treatment (the control group), incision only (the sham control group), internal fixation with or without metatarsal fracture (the internal fixation group), and continuous vibration in addition to internal fixation of metatarsal fracture, or intermittent vibration at 1, 2, 3, 5, 7 and 17-day interval in addition to internal fixation of metatarsal fracture (the vibration group). Vibration was done at frequency F=35 Hz, acceleration a=0.25g, 15 min each time 2 weeks after bone fracture. Bone healing was evaluated by micro-CT scan, bone microstructure and mechanical compression of finite element simulation. Results: Intermittent vibration at 7-day interval significantly improved bone fracture healing grade. However, no significant changes on microstructure parameters and mechanical properties were observed among sheep receiving vibration at different intervals. Conclusions: Clinical healing effects should be the top concern. Quantitative analyses of bone microstructure and of finite element mechanics on the process of fracture healing need to be further investigated.

Effects of continuous or intermittent low-magnitude high-frequency vibration on fracture healing in sheep.

PURPOSE: Vibration therapy has been shown to improve fracture healing. In this study, we investigated the effects of continuous or different intermittent vibration regimens on fracture healing in sheep models on the basis of radiographs, mechanical, and biochemical testing. METHODS: The 63 right-hind metatarsals from 63 sheep (12-month-old) were osteotomized; followed by surgical fixation with a steel plate. Two weeks after the surgery, the sheep with right-hind metatarsal fractures were randomly divided into seven groups (n=9/group): control (no vibration treated), continuous vibration (CV), one, three, five, seven and 14-day intermittent vibration (named IV-1, -3, -5, -7, and -14, respectively) groups, which represented a cycle of the successive n-day vibration and successive n-day break. Vibration stimulation (F=35 Hz, a=0.25 g) lasted 15 minutes each treatment. After eight weeks with/without vibration treatment, the sheep were euthanized with intravenous anesthetic. The callus formation, mechanical properties, and biochemical compositions of fracture metatarsals were analyzed. RESULTS: In CV and IV-7 groups, X-ray images showed an increased callus volume around the fracture area. The bone elastic modulus and the concentrations of Ca, P, and Ca/P ratio of the area at 15 and 25 mm away from the fracture centerline were higher in CV and IV-7 groups compared with the other groups. CONCLUSIONS: Our results demonstrate that both CV and IV-7 vibration patterns showed better improvement of fracture healing.

Use of an Osteoblast Overload Damage Model to Probe the Effect of Icariin on the Proliferation, Differentiation and Mineralization of MC3T3-E1 Cells through the Wnt/ß-Catenin Signalling Pathway.

BACKGROUND/AIMS: Mechanical loading plays an important role in the regulation of bone mass. However, bone cells are not always under physiological stress. In some cases, bone tissue is subjected to an overloaded mechanical environment. For example, a person who is weight training and a stevedore often experience bone pain, inflammation and other bone fatigue damage symptoms. Icariin is the major ingredient of Herba epimedii, which has been widely used for the treatment of bone injury in traditional Chinese medicine, but its mechanism remains unknown. The aim of this study was to probe the effect of icariin on the proliferation and differentiation of osteoblasts exposed to overload and to determine whether the Wnt/ß-catenin signalling pathway is involved in the drug response in osteoblasts. METHODS: Mouse MC3T3-E1 cells were exposed to mechanical tensile strain using a four- point bending device to create an overload damage model. An MTT assay was performed to determine the effects of icariin on MC3T3-E1 cell proliferation. The mRNA and protein levels of ALP, COL-I, OCN, RUNX2 and ß-catenin were assessed using RT-PCR and immunoblotting. The protein levels of ß-catenin in the MC3T3-E1 cells were also determined using fluorescence microscopy. The mineralization of osteoblasts was assessed using Alizarin Red S staining. RESULTS: We found that icariin enhanced the proliferation of osteoblasts exposed to overload and promoted MC3T3-E1 cell differentiation and mineralization. Furthermore, the gene and protein expression levels of ß-catenin and RUNX2 all increased with icariin treatment compared with those in the damage group. CONCLUSION: Our study suggested that icariin promotes proliferation and differentiation in osteoblasts exposed to overload. The effect of icariin on osteoblastic differentiation acted by activating the RUNX2 promoter and the Wnt/ß- catenin pathway.

Patellar tendon ossification after retrograde intramedullary nailing for distal femoral shaft fracture: A case report and review of the literature.

RATIONALE: Retrograde femoral nailing was one of the most important treatment means for distal femoral shaft fracture. However, studies regarding heterotopic ossification of the patellar tendon after retrograde intramedullary nailing for distal femoral shaft fracture are limited. We herein present a rare complication, namely heterotopic ossification of the patellar tendon, after retrograde intramedullary nailing for displaced femoral shaft fracture. PATIENT CONCERNS: We present a case of 25-year-old male with displaced femoral shaft fracture who was treated by retrograde intramedullary nailing. DIAGNOSES: During the period of follow-up, the patient developed symptomatic heterotopic ossification of the patellar tendon with extensively hard ossification area. INTERVENTIONS: Open surgery was recommended, but the patient has refused further treatment. OUTCOMES: The patient resulted in pain and restricted the range of motion of the affected knee. LESSONS: This case stresses the importance of longer-term follow-up and further attention into the possibility of heterotopic ossification of the patellar tendon.