Effects of intramedullary femoral fracture fixation: what is the impact of experimental studies in regards to the clinical knowledge?

Osseous Union after Jaw Reconstruction with Fibula-Free Flap: Conventional vs. CAD/CAM Patient-Specific Implants

This is a monocentric, retrospective study of patients who underwent successful immediate or delayed maxilla or mandible reconstructions with FFF from January 2005 to December 2021. Panoramic radiograph, computed tomography scans, and cone-beam CTs were analyzed concerning the osseous union of the intersegmental junctions between maxillary or mandibular native jaw and fibular bone. The primary parameter was to estimate the status of osseous union according to osteosynthesis type. A total number of 133 patients (PSI: n = 64, non-PSI: n = 69) were included in the present study. The mean age was 56.7 ± 14.0 (Range: 14.7−82.7); the primary diagnosis was in 105 patients a malignant (78.9%) and in 20 patients a benign (15.0%) tumor. Mandible reconstruction was performed on 103 patients (77.4%), and on 30 patients (22.6%), maxilla reconstruction was performed. The radiographic images provided a rate of incomplete osseous union (IOU) of about 90% in both groups in the first 6 months. Imaging between 6 and 12 months reveals an IOU rate in the non-PSI group of 46.3% vs. 52.5% in the PSI group, between 12 and 24 months, an IOU rate of 19.6% vs. 26.1%, between 24 and 36 months 8.9% vs. 21.7%, and after 36 months the IOU rate decreases to 4.2% vs. 18.2%. Multivariate logistic regression shows that only osteosynthesis type (OR = 3.518 [95%-CI = 1.223−10.124], p = 0.02) and adjuvant radiotherapy (OR = 4.804 [95%-CI = 1.602−14.409], p = 0.005) are independent risk factors for incomplete osseous union. Cox regression revealed that the variables plate-system (Hazard ratio, HR = 5.014; 95 %-CI: 1.826−3.769; p = 0.002) and adjuvant radiotherapy (HR = 5.710; 95 %-CI: 2.066−15.787; p < 0.001) are predictors for incomplete osseous union. In our study, the rate of incomplete bony fusion was significantly higher in the PSI group. Jaw-to-fibula apposition zones were significantly more affected than intersegmental zones. In multivariate analysis, a combination of osteosynthesis with PSI and adjuvant radiotherapy could be identified as a risk constellation for incomplete ossification.

Phalangeal and Metacarpal Fractures of the Hand: Preventing Stiffness

Fractures of the phalangeal or metacarpal bones of the hand are common. Many of these fractures are treated without surgery. However, both conservative and operative management of fractures of the hand can result in stiffness. Stiffness is the most common complication in the management of hand fractures. The key to preventing stiffness is early range of motion exercises. This article challenges many of the current treatment regimens offered to patients with the so-called unstable fractures. The evaluation of the patients' function is the primary factor that should determine the course of conservation versus operative management. X-rays do not demonstrate function and therefore act as an adjunct only to the care of the patient. The goal of treating hand fractures is to restore function. Early motion may not only improve healing but may also hasten the return to normal hand function. The tenets of how to prevent stiffness are described in this review.

In vitro and in vivo investigation of osteogenic properties of self-contained phosphate-releasing injectable purine-crosslinked chitosan-hydroxyapatite constructs

Bone fracture repair is a multifaceted, coordinated physiological process that requires new bone formation and resorption, eventually returning the fractured bone to its original state. Currently, a variety of different approaches are pursued to accelerate the repair of defective bones, which include the use of 'gold standard' autologous bone grafts. However, such grafts may not be readily available, and procedural complications may result in undesired outcomes. Considering the ease of use and tremendous customization potentials, synthetic materials may become a more suitable alternative of bone grafts. In this study, we examined the osteogenic potential of guanosine 5′-diphosphate-crosslinked chitosan scaffolds with the incorporation of hydroxyapatite, with or without pyrophosphatase activity, both in vitro and in vivo. First, scaffolds embedded with cells were characterized for cell morphology, viability, and attachment. The cell-laden scaffolds were found to significantly enhance proliferation for up to threefold, double alkaline phosphatase activity and osterix expression, and increase calcium phosphate deposits in vitro. Next, chitosan scaffolds were implanted at the fracture site in a mouse model of intramedullary rod-fixed tibial fracture. Our results showed increased callus formation at the fracture site with the scaffold carrying both hydroxyapatite and pyrophosphatase in comparison to the control scaffolds lacking both pyrophosphatase and hydroxyapatite, or pyrophosphatase alone. These results indicate that the pyrophosphatase-hydroxyapatite composite scaffold has a promising capacity to facilitate bone fracture healing.

Knockdown Indian Hedgehog (Ihh) does not delay Fibular Fracture Healing in genetic deleted Ihh mice and pharmaceutical inhibited Ihh Mice

The objective of this study was to determine if Ihh is required for fracture healing. Fibular fracture was created in adult Col2a1-CreER^T2; Ihh^fl/fl mice. Ihh^fl/fl mice received Tamoxifen (TM) to delete Ihh. WT mice received Cyclopamine to inhibit Hh pathway. Callus tissue properties and Ihh pathway were analyzed at 1, 2, and 3 weeks post-fracture by X-ray, micro-CT, mechanical test, RT-PCR and immunohistochemistry. Deleted Ihh was evidenced by the occurrence of growth plate closure in the Ihh^fl/fl mice by X-ray 3 weeks after TM treatment. All mice showed fracture healing at 3 weeks post-operation. Histology analysis indicated that, compared to the control, cartilage area was less in fracture sites from Ihh deficient animals by either genetic deletion or drug inhibition at 1 and 2 weeks post-fracture. Ihh immunostaining and its mRNA level were diminished in the fracture callus in Ihh reduced mice. There was no significant difference in BV/TV, BMD and mechanical test. Interruption to Ihh pathway by either genetic or pharmaceutical approach didn’t affect fibular fracture healing in these mice. This surprised finding implicates that the deleted Ihh does not affect fracture healing in this model.

Investigation of osteogenic activity of primary rabbit periosteal cells stimulated by multi-axial tensile strain

Periosteum-derived cells was indicated to respond to mechanical force and have stem cell potential capable of differentiating into multiple tissue. Investigation of osteogenic activity under mechanical stimulation is important to understand the therapeutic conditions of fracture healing. In this work, a cell culture platform was developed for respectively providing isotropic and anisotropic axial strain. Primary rabbit periosteal cells were isolated and cultured in the chamber. Multi-axial tensile strain was received and osteogenic activity was investigated by mRNA expressions of CBFA1 and OPN. The highest mRNA expression was found in moderate strain (5-8%) under anisotropic axial strain. These results provided important foundation for further in vivo studies and development of tailor-made stretching rehabilitation equipment.

In-hospital mortality from femoral shaft fracture depends on the initial delay to fracture fixation and Injury Severity Score: a retrospective cohort study from the NTDB 2002-2006

BACKGROUND

Optimal surgical timing for definitive treatment of femur fractures in severely injured patients remains controversial. This study was performed to examine in-hospital mortality for patients with femur fractures with regard to surgical timing, Injury Severity Score (ISS), and age.

METHODS

The National Trauma Data Bank version 7.0 was used to evaluate in-hospital mortality for patients presenting with unilateral femur fractures. Patients were stratified into four groups by surgical timing (ST) and four groups by ISS. χ tests were used to evaluate baseline interrelationships. Binary regression was used to examine the association between time to surgery, ISS score, age, and mortality after adjusting for patient medical comorbidities, and personal demographics.

RESULTS

A total of 7,540 patients met inclusion criteria, with a 1.4% overall in-hospital mortality rate. For patients with an isolated femur fracture, surgical delay beyond 48 hours was associated with nearly five times greater mortality risk compared with surgery within 12 hours (adjusted relative risk, 4.8; 95% confidence interval, 1.6-14.1). Only severely injured patients (ISS, 26+) had higher associated mortality with no delay in surgical fixation (ST1 < 12 hours) relative to ST2 of 13 hours to 24 hours with an adjusted relative risk of 4.2 (95% confidence interval, 1.0-16.7). The association between higher mortality rates and surgical delay beyond 48 hours was even stronger in the elderly patients.

CONCLUSION

This study supports the work of previous authors who reported that early definitive fixation of femur fractures is not only beneficial, particularly in the elderly, but also consistent with more recent studies recommending at least 12-hour to 24-hour delay in fixation in severely injured patients to promote better resuscitation.

LEVEL OF EVIDENCE

Therapeutic study, level III.

The biology of fracture healing

The biology of fracture healing is a complex biological process that follows specific regenerative patterns and involves changes in the expression of several thousand genes. Although there is still much to be learned to fully comprehend the pathways of bone regeneration, the over-all pathways of both the anatomical and biochemical events have been thoroughly investigated. These efforts have provided a general understanding of how fracture healing occurs. Following the initial trauma, bone heals by either direct intramembranous or indirect fracture healing, which consists of both intramembranous and endochondral bone formation. The most common pathway is indirect healing, since direct bone healing requires an anatomical reduction and rigidly stable conditions, commonly only obtained by open reduction and internal fixation. However, when such conditions are achieved, the direct healing cascade allows the bone structure to immediately regenerate anatomical lamellar bone and the Haversian systems without any remodelling steps necessary. In all other non-stable conditions, bone healing follows a specific biological pathway. It involves an acute inflammatory response including the production and release of several important molecules, and the recruitment of mesenchymal stem cells in order to generate a primary cartilaginous callus. This primary callus later undergoes revascularisation and calcification, and is finally remodelled to fully restore a normal bone structure. In this article we summarise the basic biology of fracture healing.

Comparison of RIA and conventional reamed nailing for treatment of femur shaft fractures

INTRODUCTION

The standard of care for femoral diaphysis fractures is sequentially reamed, locked, intramedullary nails. However, in the polytraumatized patient perioperative complications such as fat embolism syndrome (FES) and acute respiratory distress (ARDS) are well chronicled. The reamer irrigator aspirator (RIA)has been theorized to minimize such phenomena.

METHODS

A retrospective study comparing conventional reamed nailing for femur fractures versus those treated with the RIA was conducted. From January 2005 to September 2006, 156 patients treated at our institution with an intramedullary nail met inclusion criteria. There were sixty-six patient treated with conventional reaming (group A) and ninety patients treated with the RIA (group B). The main outcome measures included length of hospital stay, rate of ARDS, pneumonia, ventilatory failure, overall pulmonary complications, healing rate and death.

RESULTS

No significant differences were found between groups with regard to patient demographics, injury severity and the incidence of head/chest trauma. In addition, no differences were found in length of hospital stay, length of ICU stay or mechanical ventilation. Overall pulmonary complications occurred in 11% (group A) and 16% (group B) respectively (p = 0.48). No fatalities were found in group A while there were four in group B, 4% (p = 0.14). No significant differences were found in delayed union versus nonunion rate between groups, while overall healing complications were seen in 7% and 14% of patients (p = 0.35) in groups A and B respectively.

CONCLUSION

No statistical significance was reached with regard to pulmonary complications, healing rates or death. However, we were unable to demonstrate favorable physiologic lung parameters with RIA use compared to conventional reaming as has been described in previous animal studies. We found a trend toward more healing complications in the RIA group, but this was not statistically significant. Further study is warranted.

A new fluoroscopy-free navigation device for distal interlocking screw placement

During the treatment of tibia fracture with interlocking nails, the most uncomfortable procedure is for an orthopaedic surgeon to find the location for the distal locking screws. In this study, a fluoroscopy-free non-contact navigation device was developed for the placement of distal locking screws in the tibia intramedullary nailing. This device utilizes a 3D digitization arm integrated with spatial coordinate registration module, graphical user interface module and sound-guided navigation module. The 3D digitization arm, a five-DOF passive robotic arm, was used to register the spatial coordinates of proximal and distal landmarks just before placement of the nail. The registered coordinates were then incorporated with the coordinates of the proximal landmarks after nail placement to calculate the coordinate transformation matrix. The transformed spatial coordinates of the distal screw holes were then computed in real time for interlocking nail navigation. A sound-guided navigation module was designed in which a sound with different tones and intermittence frequencies was produced, as the probe of the digitization arm navigates toward the location of distal screw holes. No intra-operative fluoroscopy was required. In vitro assessment was performed successfully with a donor bone, and a clinical case of a young male with tibia fracture was also carried out in the operating theatre. Operation time, distal screw insertion, total radiation time and accuracy of the distal interlocking screw placement were measured. The surgery was conducted under sterile conditions without complication, and the clinical course was smooth with prompt bone healing.

Secondary effects of femoral instrumentation on pulmonary physiology in a standardised sheep model: what is the effect of lung contusion and reaming?

Intramedullary nailing is the treatment of choice for patients with femoral shaft fractures. However, there is an ongoing debate in multiple trauma patients with associated lung contusion when primary or secondary definitive stabilisation of the long bone fracture should be performed, as nailing is thought to play an important role in the pathogenesis of adult respiratory distress syndrome (ARDS). In a standardised sheep model, this study aimed to quantify the development of acute pulmonary endothelial changes, to assess the activation of polymorphonuclear leucocytes (PMNL) and to observe the effects on the coagulation system associated with the reamed nailing procedure. Furthermore, the effect of coexisting lung contusion in an experimental model was evaluated. The animals were randomly assigned to one of four different groups (6 animals/group). In control groups, only a sham operation (thoracotomy) was performed, whereas in study groups, lung contusion was induced prior to femoral stabilisation either by external fixation or reamed femoral nailing. Using bronchoalveolar lavage (BAL) pulmonary permeability changes were quantified and PMNL activation was assessed by chemiluminescence. Additionally PMNL diapedesis and interstitial lung oedema were determined by histological analysis. All animals were sacrificed 4 h after the start of the femoral instrumentation. Without an associated lung injury, instrumentation of the femoral canal with the reamed nailing technique induced a transient increase in pulmonary permeability. In the face of an induced lung contusion, reamed femoral nailing resulted in significant increases in PMNL activation, pulmonary permeability and interstitial lung oedema, compared with external fixation. Without pulmonary contusion, reaming of the femoral canal was associated with a transient increase in pulmonary permeability. This was exacerbated in the presence of lung contusion along with increased PMNL activation. External fixation did not provoke similar changes. The findings of this study support the view that reaming of the femoral canal should be avoided in polytrauma patients with severe chest trauma as it could act as an additional stimulus for adverse outcome. Temporary external fixation appears to be a safe method for fracture stabilisation until inflammatory and coagulatory disturbances after trauma have been normalized.

Endogenous cannabinoids are candidates for lipid mediators of bone cement implantation syndrome

Acute hypotension, hypoxemia, cardiac arrhythmias, cardiac arrest, (or a combination of these), and sudden death are well-recognized complications of the cemented hip arthroplasty procedure. Collectively, these are known as the bone cement implantation syndrome (BCIS). The endogenous cannabinoids, anandamide (ANA) and 2-arachidonylglycerol (2-AG), are reported to be strong vasodilators and play a role in the hypotension associated with hemorrhagic and septic shock. In the present study, a potential role for the endogenous cannabinoids in influencing hemodynamic variables in BCIS was investigated. Thirty-five patients (35 hips) entered a prospective, randomized clinical trial. The patients were divided into two groups. Group 1 comprised 16 patients who had the component inserted using a conventional cementing technique, whereas group 2 consisted of 19 patients who had the femoral component inserted without cement. Blood samples were taken at six consecutive time points: before anesthesia, after reaming the femur, 2 min after insertion of stems with or without cement into the femur, and 10 min, 20, and 30 min after stem insertion. In group 1 (with cement), the mean levels of ANA and 2-AG significantly increased after stem insertion. In a comparison of each group after stem insertion, mean ANA and 2-AG levels in group 1 also significantly differed from those in group 2. By contrast, in group 2 (without cement) neither ANA nor 2-AG levels exhibited a significant increase or change at any point in time. In conclusion, we have shown for the first time that endogenous cannabinoids are candidates for lipid mediators of BCIS.

Minimally invasive unicompartmental knee replacement: rationale and correct indications

In the early 1990s, unicompartmental knee replacements (UKRs) were almost forgotten as an option for the management of unicompartmental arthritis of the knee, and the two principal surgical options became proximal tibial osteotomy and total knee replacement. The recent introduction of minimally invasive techniques has renewed interest in uni-compartmental knee replacement. The proposed advantages of UKR over proximal tibial osteotomy include more predictable relief of pain, quicker recovery, and better long-term results. In appropriate cases, it has advantages over total arthroplasty in providing more physiologic function, better range of movement, easier salvage in case of failure, and quicker recovery because of minimally invasive techniques.