The healing forearm fracture: a matched comparison of forearm refractures

BACKGROUND: Forearm fractures in children usually heal rapidly after closed treatment. Recent studies report forearm refracture rates of 5%. The purpose of this study was to identify risk factors for refracture based on radiographic variables. METHODS: We performed a retrospective review of patients that sustained a second forearm fracture (refracture) between 1998 and 2005. Refractures were defined as having a second fracture of the same forearm within 18 months of the original fracture. A comparison group of single-fracture patients followed in a capitated insurance plan were included and matched based on age and sex. Radiographic assessment included initial/final angulation, displacement, and fracture-line visibility at latest follow-up. RESULTS: Sixty-three refractures were compared with 132 age- and sex-matched single-fracture patients. Time to refracture averaged 10 months. Thirty-eight percent of the initial fractures in the refracture group occurred in the proximal or middle third of the forearm compared with 15% for the single-fracture patients (P < 0.001). Because location of the fracture was found to be a risk factor for refracture, a secondary analysis was performed with refracture patients matched to single-fracture patients based on age, sex, bone fractured, fracture location, and treatment method. Fracture-line visibility of the radius at latest follow-up was clearly visible in 48% of refractures compared with 21% of controls (P = 0.05). Initial fracture severity and residual deformity were not significantly different. CONCLUSIONS: Proximal and middle one third forearm fractures are at greater risk of refracture compared with distal one third forearm fractures. There was a trend toward incomplete healing seen more commonly in those that refractured, emphasizing the importance of longer immobilization in these fractures. LEVEL OF EVIDENCE: Prognostic study, level III, case-control study.     

Osteoporotic vertebral fracture adjacent to a nonsegmented hemivertebra

A combination of osteoporotic vertebral fractures and congenital spinal deformity is theoretically possible, but there have been no reports on this combination in the literature. We describe a rare case of an osteoporotic vertebral fracture adjacent to the nonsegmented hemivertebra. A 60-year-old postmenopausal woman who did not recall any specific trauma presented with severe back pain. She had markedly decreased bone mineral density and significant lumbar kyphoscoliosis with a nonsegmented hemivertebra between L1 and L2 on radiographs of the lumbar spine. Magnetic resonance imaging (MRI) revealed a vertebral fracture adjacent to the nonsegmented hemivertebra. Laboratory studies showed increased serum bone-specific alkaline phosphatase (BAP) and urinary type I collagen crosslinked N-telopeptide (NTx). A thoracolumbar brace was applied for 3 months. Daily administration of alendronate normalized her serum BAP and urinary NTx levels. MRI scans of the lumbar spine after 6 months also confirmed normalized signal intensities of the fractured vertebra adjacent to the nonsegmented hemivertebra. The vertebral fracture seemed to be induced by spinal malalignment, increased stress on the adjacent level of the fused segment, and its fragility due to osteoporosis.     

Monitoring of fracture healing by electrical conduction: A new diagnostic procedure

Background:

Electrical stimulation of fractures has been reported to enhance fracture healing. X-rays are normally used to assess union of fractures. Electrical conduction is not tried as a tool to study fracture healing. The current study focuses on electrical conduction as a diagnostic tool to assess fracture healing and new bone formation. The aim was to find if electrical resistance across the fracture can be used as a tool to study fracture healing which can be verified with simultaneous radiographs.

Materials and Methods:

A prospective study was conducted where 12 open fractures of tibia, including two with bone defects were evaluated. They were debrided and four-carbon ring Ilizarov external fixators were applied. Their healing was followed with clinical assessment and periodical X-rays till the endpoint of fracture union and then the rings were removed. In addition, all these cases also had application of electrical voltage in the range of 0.1–1.0 V DC in 0.1 V increments, across the two wires on either side of fracture. The output current was recorded by an ammeter connected in series. Resistance calculated for various voltages was plotted as a graph for the period of fracture treatment and the characteristics were studied. This graph was compared with the appearance of new bone in the X-rays.

Results:

In all cases, when the above graph stabilized, in the consecutive recordings, the X-rays showed healing (bridging callus) matching the curve and the patient was able to load the limb. The time of stabilization of this graph for a specific voltage was different in individual cases. However, for a given case, the resistance characteristics were the same for the entire voltage range of 0.1–1.0 V.

Conclusion:

If the resistance versus day curve stabilizes on the consecutive recordings, we can predict that the fracture is in the process of healing. This stabilization period also matched the patients’ ability to comfortably load the limb and also the radiographs which showed bridging callus (healing). If this is used as a positive criterion for fracture healing in future, the radiation exposure by X-rays shall be less.     

A novel way to dynamize a spatial frame and optimize fracture healing

BackgroundFracture site motion creates mechanical strains on the healing tissues which influences bone formation. Axial micro-motion maximizes dilatational strains, whereas shearing motions maximize deviatoric strains on the healing tissues. Dilatational strains optimize bone healing, deviatoric strains retard bone healing. Dynamization of external fixation using either an Ilizarov or Spatial Frame platform is used to increase loading on the limb which increases the mechanical stress and strain on the tissues to improve healing. The scientific literature does not address how dynamization of the spatial frame effects fracture site motion. The purpose of this study is to assess the effect of modified shoulder bolts incorporated into a spatial frame during dynamic loading.MethodsFive identical two-ring spatial frame constructed were mounted on Sawbones tibias with an osteotomy performed distal to the tibial tubercle. Sinusoidal load was applied at a rate of 0.25 Hz. Axial force and displacement, in addition to motion of the proximal and distal tibia segments were recorded. Eight constructs were tested: 1) All struts of the Spatial Frame rigid, 2) Strut #1 loose, 3) Struts #1 and #3 loose, 4) Struts #1, #3 and #5 loose, 5) All struts loose, 6) All struts rigid with dynamization bolts on the proximal end, 7) All struts rigid with dynamization bolts on alternating sides, 8) Threaded rods between the rings with two millimeters of dynamization.ResultsNo difference in vertical displacement was observed between the Ilizarov and all struts locked. No significant difference in shear values between all struts locked and modified shoulder bolt struts was observed. Increase in vertical movement with the modified shoulder bolts was an average of 1.83 mm. Significant shear forces at the fracture site were observed with unlocking single or multiple struts of the spatial frame.ConclusionModified shoulder bolts can be used for spatial frame dynamization without increasing shear motion.     

Internal remodeling of periosteal new bone during fracture healing

A closed fracture model of the rat tibia was employed to study internal remodeling of periosteal new bone during fracture repair. Static histomorphometric parameters of osteoid surface (or perimeter) and eroded surface (resorption surface) were used as indicators of appositional bone formation and resorption of bone trabeculae, respectively. Intracortical remodeling at the fracture site was evaluated using quantitative tetracycline histology and microradiography. The extents of osteoid and eroded bone surfaces did not differ significantly in the periosteal woven new bone in the early phases of fracture healing. Later on, the periosteal new bone had significantly more osteoid surface than eroded surface (p less than 0.001). The number of osteoclasts also decreased significantly over time during fracture healing (p = 0.028). Cortical bone showed a continuous increase of porosity (p less than 0.01) between 1 and 6 weeks after fracture. These results suggest that there is a time-related change in the balance of periosteal bone formation and resorption during the progress of fracture repair. We hypothesize that this change was related to the restoration of bony continuity. Further studies are, however, needed to indicate the histomorphometric features of periosteal new bone in fracture nonunions.     

A novel mouse model to study fracture healing of the proximal femur

The majority of fractures, especially in elderly and osteoporotic patients, occurs in metaphyseal bone. However, only a few experimental models exist to study metaphyseal bone healing in mice. Currently used mouse models of metaphyseal fracture healing are either based on drill hole defects, lacking adequate biomechanical stimulation at the site of fracture and therefore endochondral ossification in the fracture callus, or are introduced into the distal part of the mouse femur stabilized by a locking plate, which is challenging due to the small specimen size. Therefore, the aim of the current study was to develop a new mouse model to study metaphyseal fracture healing of the proximal femur. We chose a combination between an open osteotomy and a closed intramedullary stabilization. A 24 G needle was inserted into the femur in a closed manner, then an osteotomy was made with a 0.4-mm Gigli wire saw between the third and the lesser trochanter of the femur using an open approach. Fractured femurs were analyzed using microcomputed tomography and histology at days 14 and 21 after surgery. No animals were lost due to surgery or anesthesia. All animals displayed normal limb loading and a physiological gait pattern within the first three days after fracture. We found robust endochondral ossification during the fracture healing process with high expression of late chondrocyte and early osteogenic markers at day 14 (d14). By day 21 (d21), all fractures had a bony bridging score of 3 or more, indicating successful healing. Callus volume significantly decreased from d14 to d21, whereas high numbers of osteoclasts appeared at the fracture callus until d21, indicating that callus remodeling had already started at d21. In conclusion, we successfully developed a novel mouse model to study endochondral fracture healing of the proximal femur. This model might be useful for future studies using transgenic animals to unravel molecular mechanisms of osteoporotic metaphyseal fracture healing.     

Unusual arterial injury following a fracture of the forearm bones: A case report

The author describes a case of a 10-year-old boy with fracture of both forearm bones and a concomitant partial rupture of the ulnar artery. The damage to the ulnar artery was repaired at the time of fasciotomy with a good functional outcome.     

Use of a polymeric device to deliver growth factors to a healing fracture

Background: Fracture healing is a cascade of events regulated by systemic and local factors. Local growth factors are believed to play an integral role. The present study evaluates the effects of basic fibroblast growth factor (bFGF) and insulin‐like growth factor‐1 (IGF‐1) using a controlled delivery system in a closed rodent femoral fracture model. Methods: Female Wistar rats (n = 144) were used in the present study. Animals were randomly allocated to six groups, with each group divided into three time‐points of 2, 4 and 8 weeks. Two groups had growth factor administered. The others had no operation or sham operations. Growth factors were delivered to the fracture site using a specialised delivery system. This consisted of a Kirschner‐wire coated with ethylene vinyl acetate co‐polymer embedded with growth factors, inserted as an intramedullary nail. Fractures were effected with a three‐point bending device. Femurs were tested in four‐point bending and structural properties of peak load and stiffness were obtained from the load‐displacement graphs. Specimens were prepared for qualitative analysis under a light microscope and using immunohistochemistry, specimens were analysed for expression of bFGF, IGF‐1 and transforming growth factor β (TGF‐β). Results: The growth factor‐treated groups exhibited larger calluses at 2 and 4 weeks. Four‐point bending showed weaker structural properties (stiffness and peak load) at 4 weeks in both growth factor‐treated groups. Administration of bFGF or IGF‐1 increased the ratio of cartilaginous to mesenchymal tissues in the fracture callus compared with non‐treated animals at 2 and 4 weeks. Immunostaining intensity and distribution of both growth factors in the treated groups was greater than the non‐treated groups. Conclusion: Exogenous delivery of bFGF or IGF‐1 alters the course of fracture healing.     

Fatigue fracture of a forearm plate within a long-arm cast

Open fractures of both left ulna and radius, in which a segment of the radius was found to be missing, occurred in a 27-year-old man. The fractures were treated by open reduction, internal fixation with ASIF semitubular plates, and bone graft. Because of slow radiological union, regrafting was required twice. Approximately six months after the third operation, roentgenograms showed that the bone plate was broken, even though the fractures had been protected in a long-arm cast. The fatigue fracture of the plate, positioned on the posterior surface of the ulna, was presumably caused by the force of the finger flexors, most of which originate above the fracture site, and which were still able to contract because the fingers were not immobilized.     

Scintigraphical observation to predict fracture healing in intracapsular fracture of the femoral neck

Predictive clinical value of scintigraphical classification of the femoral head in intracapsular fracture of the femoral neck, as classified by Hirano, et al. in 1987, was investigated by long-term follow-up (mean; 4 years and 7 months). Normal healing was achieved in 21 of 24 patients. In those cases, early 99mTc-MDP scintigraphy revealed an over-all increase of radionuclide uptake (Type A) and band-like decrease along the fracture (Type B1). Late segmental collapse of the femoral head was found in 3 patients who showed either a decrease in the weight-bearing area (Type B2) or over-all decrease of radionuclide uptake (Type C). The results of fracture healing were well correlated to each type of scintigraphical classification. The changes of radionuclide uptake in the fracture site were also followed by serial 99mTc-MDP scintigraphy.