Titanium versus stainless steel alloy bridge plates for distal femur fractures: Does callus form earlier with titanium?

INTRODUCTION: Distal femur fractures account for 3-6% of all femur fractures. Internal fixation of most distal femur fractures with an anatomic lateral locking plate should permit some motion at the metaphyseal portion of the fracture when secondary bone healing is planned by the operating surgeon. While several studies have been performed evaluating union rates for distal femur fractures with stainless steel and titanium plates, the timing of callus formation between stainless steel and titanium implants used as bridge plates for distal femur fractures (AO/OTA 33-A and -C) has been investigated to a lesser extent. We hypothesize that callus will be visualized earlier with post-operative radiographs with titanium versus stainless steel bridge plates. METHODS: We retrospectively reviewed a consecutive cohort of patients over 18 years of age with acute AO/OTA 33-A and 33-C fracture patterns treated with an isolated stainless steel or titanium lateral bridge plate within 4 weeks of injury by a single fellowship-trained orthopedic trauma surgeon from 2011 to 2020 at one academic Level 1 trauma center. An independent, fellowship-trained orthopedic trauma attending surgeon reviewed anterior-posterior (AP) and lateral radiographs from every available post-operative clinic visit and graded them using the Modified Radiographic Score for Tibia (mRUST). RESULTS: Twenty-five subjects were included in the study with 10 with stainless steel and 15 with titanium plates. There were no significant differences in demographics between both groups, including age, sex, BMI, injury classification, open versus closed, mechanism, and laterality. Statistically significant increased mRUST scores, indicating increased callus formation, were seen on 12-week radiographs (8.4 vs. 11.9, p = 0.02) when titanium bridge plates were used. There were no statistically significant differences in mRUST scores at 6 or 24-weeks, but scores in the titanium group were higher in at every timepoint. DISCUSSION: In conclusion, we observed greater callus formation at 12 weeks after internal fixation of 33-A and 33-C distal femur fractures treated with titanium locked lateral distal femoral bridge plates compared to stainless steel plates. Our data suggest that titanium metallurgy may have quicker callus formation compared to stainless steel if an isolated, lateral locked bridge plate is chosen for distal femur fracture fixation.

Evaluation of the mechanical behaviour of the expandable wedge locked nail fixation in retrograde use: A finite element study.

INTRODUCTION: In literature, there have been many studies conducted to research the alternatives of standard interlocking intramedullary nailing. The expandable wedge locked nail fixation, which is thought as a new alternative to the standard interlocking nailing, has been presented in previous numerical studies. The antegrade usage of the wedge locked nail fixation has provided promising results. From this point, the aim of the study is to evaluate mechanical behavior of its retrograde usage on femur models. Additionally, another aim of the study is to investigate the effect of fracture level on mechanical properties of the fixation. MATERIALS AND METHODS: The mechanical behaviors of the wedge locked nail and standard interlocking nail fixations were compared by finite element methods. Sawbones femurs having osteotomies at five different levels to simulate different fractures were fixed with wedge locked nail or interlocking nail by using retrograde approach. With respect to the fracture level, two different nail lengths were used. Axial compression load was applied to fixations. The mechanical behaviors of the fixations were evaluated with respect to stiffness of the fixations and stresses occurred on both implants and bones. RESULTS: Any of the wedge locked nail fixation did not slip at canal. The stress and stiffness results were mostly close with each other for both nail types. The maximum stresses at locking elements or bones contacting these elements increased with decreased distance between the fracture and relevant locking elements. DISCUSSION: The wedge locked nail fixation showed comparable results to the standard interlocking nail fixation with respect to the stiffness and stress. Under axial loading, wedge locked nail provided a secured fixation without any slippage and preserved its position inside the medullary canal. It may be thought as a safe alternative to the standard interlocking nail fixation for retrograde usage. Additionally, according to stress results, it is advised to the surgeons to avoid a close locking to the fracture line.

Influence of a change in activity regime on femoral bone architecture and failure behaviour.

The incidence and morbidity of femoral fractures increases drastically with age. Femoral architecture and associated fracture risk are strongly influenced by loading during physical activities and it has been shown that the rate of loss of bone mineral density is significantly lower for active individuals than inactive. The objective of this work is to evaluate the impact of a cessation of some physical activities on elderly femoral structure and fracture behaviour. The authors previously established a biofidelic finite element model of the femur considered as a structure optimised to loading associated with daily activities. The same structural optimisation algorithm was used here to quantify the changes in bone architecture following cessation of stair climbing and sit-to-stand. Side fall fracture simulations were run on the adapted bone structures using a damage elasticity formulation. Total cortical and trabecular bone volume and failure load reduced in all cases of activity cessation. Bone loss distribution was strongly heterogeneous, with some locations even showing increased bone volume. This work suggests that maintaining the physical activities involved in the daily routine of a young healthy adult would help reduce the risk of femoral fracture in the elderly population by preventing bone loss.

Minimally invasive plate osteosynthesis for complex comminuted bone fractures in the Fraser's type II floating knee: a case report.

OBJECTIVE: Floating knee type IIC, according to Fraser's classification, is an uncommon severe injury that typically occurs in polytrauma. In such cases, intra-articular fracture and the high degree of comminution and deformity of the mid-distal femur make fixation challenging. The purpose of this study was to demonstrate that minimally invasive plate osteosynthesis (MIPO) technology can simplify these complex problems and improve patient prognosis. CASE PRESENTATION: A 38-year-old man injured his left leg in a car accident, causing pain, swelling, deformity, and limited mobility on his left knee and thigh, and two small open wounds were noted mainly of the anterior aspect of the mid-distal thigh. Physical examination and computed tomography angiography of the lower limb confirmed that there was no damage to the neurovascular system. The clinical diagnosis was closed intra-articular fracture of the proximal tibia, open intra-articular fracture of the distal femur with extension to the diaphysis, and a patellar fracture on the ipsilateral knee. The treatment strategy involved a locking plate system applying MIPO technology. Postoperative evaluation of the patient was satisfactory, with immediate functional exercise, full weight-bearing after three months, and return to daily activity without pain. Final follow-up taken 3 years after surgery showed good lower limb alignment and complete plasticity of the bone structure, by which time the patient showed good limb function. CONCLUSIONS: Minimally invasive techniques can provide a simple and effective treatment for some complex fractures.

Biomechanical comparison of lag screw and non-spiral blade fixation of a novel femoral trochanteric nail in an osteoporotic bone model.

There is no consensus regarding the advantages of the lag screw type over the blade type for treating femoral trochanteric fractures. We aimed to investigate whether non-spiral blade (Conventional-Blade, Fid-Blade) nails provide better biomechanical fixation than lag screws in a severe osteoporotic bone model. Different severities of osteoporotic cancellous bone were modelled using polyurethane foam blocks of three densities (0.24, 0.16, and 0.08 g/cm3). Three torsional tests were performed using each component for each density of the polyurethane block, and the maximum torque was recorded; subsequently, the energy required to achieve 30° rotation was calculated. Using a push-in test, the maximum force was recorded, and the energy required to achieve 4-mm displacement was calculated. For 0.08-g/cm3 density, the peak torques to achieve 30° rotation, energy required to achieve 30° rotation, peak force to achieve 4-mm displacement, and energy required to achieve 4-mm displacement were significantly greater for Conventional-Blade and Fid-Blade than those for Lag Screw. The fixation stability of the blade-type Magnum nail component is better than that of the lag screw type under any test condition. The blade-type nail component may have better fixation stability than the lag screw type in a severe osteoporotic bone model.

Efficacy of fascia iliaca nerve block in daily routine for children with femoral fractures in a pediatric emergency department.

OBJECTIVES: We aimed to evaluate the efficacy of fascia iliaca nerve block (FINB), routinely used for children with femoral fractures, in a pediatric emergency department (PED). METHODS: This retrospective, single-center, observational study examined FINB using ropivacaine and a 1% lidocaine hydrochloride solution, in all patients under 18 years of age admitted with a femoral fracture from January 2012 to December 2016. Pain was assessed using two validated pediatric pain scales: EVENDOL or a visual analog scale. A level of ≥ 4 on either scale indicates the need for an analgesic. The primary outcome was the percentage of patients who were pain free after the FINB procedure defined by a pain score of < 4. Secondary outcomes were the time spent between PED admission and FINB, the need of additional analgesics, side effects, and the success rate of FINB. RESULTS: Of 161 patients screened, 144 were included. The median age was 3.2 years (range 2 months to 16 years) and 74% were boys. The number of children determined to be pain free (pain score < 4) increased from 36 (25%) before the FINB to 123 (85%) after the FINB (absolute risk difference 60%, 95% CI: 51%-70%). Overall, 21 children (15%) required a second analgesic after the FINB. CONCLUSION: The routine use of FINB with ropivacaine and lidocaine by pediatric ED physicians provided effective pain relief for children admitted for a femoral fracture in the emergency department. Our data support the efficiency and feasibility of FINB for the antalgic management of children with femoral fracture.

Biomechanics of the Femoral Head Cartilage and Subchondral Trabecular Bone in Osteoporotic and Osteopenic Fractures.

This study aimed to investigate the relationship between the micro structural properties of the subchondral trabecular bone (STB) and the macro mechanical properties of the articular cartilage (AC) in patients with osteoporotic (OP) and osteopenic (OPE) fractures. Sixteen femoral head samples (OP;OPE, n = 8 each) were obtained from female patients who underwent hip hemiarthroplasty. STB and AC specimens were harvested from those heads. Bone specimens were scanned using µ-CT to determine the micro structural properties. In-situ nondestructive compressive tests were performed for the cartilages to obtain elastic properties. The finite element technique was implemented on STB models created from µ-CT data to compute apparent elastic modulus. In addition, dynamic cyclic destructive tests were performed on STB and AC specimens to assess failure cycles. The results demonstrated that STB specimens in OPE group have more interconnected structure and higher cyclic dynamic strength than those in OP group. Furthermore, bone mineral density, failure cycle, and trabecular number of STB were positively correlated with the cartilage failure cycle, which indicates that STB alteration may affect the macroscopic mechanical properties of AC. The findings suggest that STB loss correlates with a decrease in cartilage strength and that improving of bone quality may prevent cartilage weakness.

Correlation between lag screw route and the ideal insertion point of the intramedullary nail.

Understanding the morphology of the superior aspect of the proximal femur is critical for treating femoral fracture. We assessed the correlation among the ideal insertion point of the femoral nail, femur head-neck axis, and native anteversion. One hundred patients with normal femurs were included in this study. Computed tomography (CT) images of the proximal femur superior aspect and amount of native anteversion were acquired. Generalised Procrustes analysis showed the morphological characteristics of the superior proximal femur according to native anteversion amount. Morphological characteristics were represented by 4 parameters; the correlation between parameters and native anteversion was investigated using CT data. The passing point of the line from the proximal femoral canal parallel to the native anteversion at the greater trochanter was located more posteriorly (mean 35.6%); the passing point of native anteversion was posterior in the femoral neck and head, although the line of the head-neck centre passed more anteriorly at the greater trochanter (mean 67.5%). This posterior translation was significantly associated with native anteversion amount. Morphometric geometric analysis showed that the lag screw could not pass head-neck centre from the nail inserted into proximal femoral canal. Anterior insertion of the nail was needed for positioning the lag screw centre.

Malrotation of Long Bones.

Rotational malreduction is a common yet underreported postoperative complication following intramedullary nailing of long bone fractures. In most situations, this can be prevented at the time of initial surgery with meticulous preoperative planning, careful use of intraoperative fluoroscopy, and awareness of risk factors for malrotation. However, rotational alignment remains difficult to assess by clinical examination so a high index of suspicion is always necessary. Here, the authors review the literature on this complication and report on 3 such cases of femoral and the tibial malrotation, methods for calculating femoral version and tibial torsion, and techniques for correcting these deformities.

Early Reciprocal Effects in a Murine Model of Traumatic Brain Injury and Femoral Fracture.

Traumatic brain injury (TBI) represents a major cause of death and disability in early adulthood. Concomitant extracranial injury such as long bone fracture was reported to exacerbate TBI pathology. However, early reciprocal effects and mechanisms have been barely investigated. To address this issue, C57BL/6N mice were subjected to either the controlled cortical impact (CCI) model of TBI, fracture of the left femur (FF), combined injury (CCI+FF), or sham procedure. Behavioral alterations were monitored until 5 days post injury (dpi), followed by (immuno-)histology, gene and protein expression analyses using quantitative PCR, western blot, and ELISA. We found that CCI+FF mice exhibited increased neurological impairments, reduced recovery, and altered anxiety-related behavior compared to single injury groups. At 5 dpi, cerebral lesion size was not affected by combined injury but exaggerated hippocampal substance loss and increased perilesional astrogliosis were observed in CCI+FF mice compared to isolated CCI. Bone gene expression of the osteogenic markers Runx2, osteocalcin, alkaline phosphatase, and bone sialoprotein was induced by fracture injury but attenuated by concomitant TBI. Plasma concentrations of the biomarkers osteopontin and progranulin were elevated in CCI+FF mice compared to other experimental groups. Taken together, using a murine model of TBI and femoral fracture, we report early reciprocal impairments of brain tissue maintenance, behavioral recovery, and bone repair gene expression. Increased circulating levels of the biomarkers osteopontin and progranulin indicate ongoing tissue inflammation and repair. Our results may have implications for future therapeutic approaches to interfere with the pathological crosstalk between TBI and concomitant bone fracture.

Removal of cement-augmented screws in distal femoral fractures and the effect of retained screws and cement on total knee arthroplasty: a biomechanical investigation.

BACKGROUND: Given the increasing number of osteoporotic fractures of the distal femur, screw augmentation with bone cement is an option to enhance implant anchorage. However, in implant removal or revision surgeries, the cement cannot be removed from the distal femur without an extended surgical procedure. Therefore, the aims of this study were to investigate (1) whether cement augmentation has any influence on screw removal and removal torque, and (2) whether the implantation of a femoral component of a knee arthroplasty and its initial interface stability are affected by the remaining screws/cement. MATERIAL AND METHODS: Eight pairs of fresh-frozen human female cadaveric distal femurs (mean age, 86 years) with a simulated AO/OTA 33 A3 fracture were randomized in paired fashion to two groups and fixed with a distal femoral locking plate using cannulated perforated locking screws. Screw augmentation with bone cement was performed in one of the groups, while the other group received no screw augmentation. Following biomechanical testing until failure (results published separately), the screws were removed and the removal torque was measured. A femoral component of a knee arthroplasty was then implanted, and pull-out tests were performed after cement curing. Interference from broken screws/cement was assessed, and the maximum pull-out force was measured. RESULTS: The mean screw removal torque was not significantly different between the augmented (4.9 Nm, SD 0.9) and nonaugmented (4.6 Nm, SD 1.3, p = 0.65) screw groups. However, there were significantly more broken screws in in the augmented screw group (17 versus 9; p < 0.001). There was no significant difference in the pull-out force of the femoral component between the augmented (2625 N, SD 603) and nonaugmented (2653 N, SD 542, p = 0.94) screw groups. CONCLUSION: The screw removal torque during implant removal surgery does not significantly differ between augmented and nonaugmented screws. In the augmented screw group, significantly more screws failed. To overcome this, the use of solid screws in holes B, C, and G can be considered. Additionally, it is possible to implant a femoral component for knee arthroplasty that retains the initial anchorage and does not suffer from interference with broken screws and/or residual cement. LEVEL OF EVIDENCE: 5.

Repurposing denosumab for recalcitrant bone healing.

Fracture healing has four phases: haematoma formation, soft callus, hard callus and remodelling. Often, non-healing fractures have an arrest of one of these phases, which need resurgery. We have repurposed denosumab for impaired fracture healing cases to avoid surgical intervention. Here, we report a series of three cases of impaired fracture healing where denosumab was given 120 mg subcutaneous dosages for 3 months to enhance healing. All the three cases have shown complete bone union at a mean follow-up of 6.7 months (5-9 months) as assessed clinically and radiologically, and have observed no adverse effect of the therapy. Denosumab given in this dose aids fracture healing by increasing callus volume, density and bridges the fracture gap in recalcitrant fracture healing cases where the callus fails to consolidate.

Case series and finite element analysis of PFNA combined with cerclage wire for treatment of subtrochanteric fracture of femur.

OBJECTIVE: To retrospectively analyze the clinical efficacy of PFNA combined with a cerclage wire in the treatment of 52 patients with unstable subtrochanteric fracture of the femur and to analyze the biomechanical effect of ligature on a fracture model. METHODS: In this study, 52 patients with unstable subtrochanteric fractures were treated in our orthopedic trauma center from June 2013 to July 2018. The Seinsheimer type IV fracture model was established using the patient's CT data, and the joint surface of the distal femoral condyle and the external condyle were restrained. The femoral head was used as the loading point, and a force of 500 N was applied vertically along the long axis of the femoral shaft. RESULTS: All 52 patients were followed up for 12 to 37 months, with an average of 18.07 ± 4.38 months. According to the Sanders hip function score, 28 cases were excellent (55-60 points), 22 cases were good (45-54 points), and 2 cases were poor (35-44 points), with an excellent and good rate of 96.15%. Postoperative deep vein thrombosis occurred in 3 cases, and fracture nonunion occurred in 1 case. No infection, loose fracture of internal fixation or hip varus deformity occurred. The finite element analysis indicated that the displacement of the whole model decreased slightly and the relative sliding of the fracture block decreased, but the maximum stress of the femur increased after the addition of the cerclage wire. CONCLUSION: The treatment of unstable subtrochanteric fracture of the femur with PFNA combined with cerclage wire has the advantages of simple operation, satisfactory reduction of fracture, stable fixation, and good recovery of limb function. The finite element analysis suggested that the biomechanical strength fixation was enhanced after the addition of cerclage wire. However, the local stress concentration of the tie may increase the risk of failure.

The Association Between Traumatic Brain Injury and Accelerated Fracture Healing: A Study on the Effects of Growth Factors and Cytokines.

Evidence suggests that some systemic and local factors, including cytokines and growth factors in patients with traumatic brain injury (TBI), can play an essential role in accelerating fracture healing. The purpose of this study was to evaluate serum levels of some inflammatory cytokines and growth factors in patients with fracture and TBI as well as healthy subjects. In this study, a total number of 30 patients with a femoral fracture, 30 cases with TBI, 30 patients with TBI and a femoral fracture (fracture + TBI group), and 30 healthy subjects were recruited. The Glasgow Coma Scale (GCS) scores were also determined upon their admission. Then, the serum levels of fibroblast growth factor 2 (FGF-2), transforming growth factor-beta (TGF-ß), platelet-derived growth factor (PDGF), bone morphogenetic protein 2 (BMP-2), insulin-like growth factor 1 (IGF-1), interleukin-1 beta (IL-1ß), and interleukin-6 (IL-6) were measured via enzyme-linked immunosorbent assay (ELISA) technique, 12 h and 4 weeks after injury and hospital admission. The study results demonstrated that the serum levels of BMP-2, FGF-2, IL-1ß, and PDGF in the femoral fracture + TBI group increased significantly over 12 h and after 4 weeks compared with other groups, but the serum levels of IGF-I, IL-6, and TGF-ß in this group increased in a significant manner at 12 h compared with other studied groups. The findings also showed that the time to union of a femoral fracture was shorter in the fracture + TBI group than in cases with a femoral fracture alone (p = 0.03). Accordingly, it seems that elevated serum levels of BMP-2, PDGF, FGF-2, and IL-1ß may be associated with healing acceleration in fracture + TBI patients. However, further studies are needed to confirm this claim.

Investigation of femur fracture potential in common pediatric falls using finite element analysis.

A finite element (FE) model of an 11-month-old child's femur was developed to evaluate fracture risk in short-distance feet-first falls and bed falls. Pediatric material properties were applied to the FE model. Femur loading was derived from previously conducted fall experiments using a child surrogate where fall conditions (e.g., fall height, impact surface) were varied. Fracture thresholds based on principal stress and strain were used to examine potential for fracture. Peak stress/strain were significantly greater for feet-first falls from greater heights and onto harder impact surfaces. Feet-first falls exceeded some, but not all fracture thresholds. Bed falls did not exceed any fracture thresholds.

A novel MRI compatible mouse fracture model to characterize and monitor bone regeneration and tissue composition.

Over the last years, murine in vivo magnetic resonance imaging (MRI) contributed to a new understanding of tissue composition, regeneration and diseases. Due to artefacts generated by the currently used metal implants, MRI is limited in fracture healing research so far. In this study, we investigated a novel MRI-compatible, ceramic intramedullary fracture implant during bone regeneration in mice. Three-point-bending revealed a higher stiffness of the ceramic material compared to the metal implants. Electron microscopy displayed a rough surface of the ceramic implant that was comparable to standard metal devices and allowed cell attachment and growth of osteoblastic cells. MicroCT-imaging illustrated the development of the callus around the fracture site indicating a regular progressing healing process when using the novel implant. In MRI, different callus tissues and the implant could clearly be distinguished from each other without any artefacts. Monitoring fracture healing using MRI-compatible implants will improve our knowledge of callus tissue regeneration by 3D insights longitudinal in the same living organism, which might also help to reduce the consumption of animals for future fracture healing studies, significantly. Finally, this study may be translated into clinical application to improve our knowledge about human bone regeneration.