Internal Fixation Devices Research Articles

Effective treatment of non-union after internal fixation of femoral neck fracture using integrated traditional Chinese and western medicine.

Hip fractures, particularly femoral neck and intertrochanteric fractures, represent approximately 6.37 % of all fractures, with incidence rates showing an upward trend annually. This report presents a case of a 55-year-old female with a femoral neck fracture who underwent internal fixation. One-year post-surgery, the patient continued to experience hip pain, and computed tomography (CT) scans revealed non-union of the fracture. The patient received an integrated treatment approach combining traditional Chinese and Western medicine, involving the alternating administration of osteopeptide tablets and Guijia Jiangu capsules, a proprietary herbal formulation. No additional pharmacological or surgical interventions were employed. Seven months after initiating the treatment, digital radiography (DR) examinations showed that the fracture had largely healed. At the seven-month follow-up, and nearly four years thereafter, the patient reported no discomfort in the hip region. Subsequent DR examinations revealed no signs of avascular necrosis of the femoral head, and no adverse events were noted. The internal fixation device was removed five years post-fracture. The results indicate that integrated traditional Chinese and Western medicine may effectively treat non-union after internal fixation of femoral neck fractures, though further studies are warranted to confirm these outcomes.

Investigation of the safety of position-based titanium plate fixation for costal cartilage injuries.

Costal cartilage injuries are unappreciated, and there is a paucity of reports on fixation methods. This study aims to evaluate the safety of titanium plate internal fixation for costal cartilage injuries. A retrospective analysis was conducted on 30 patients with costal cartilage injuries who underwent titanium plate internal fixation between April 2016 and November 2022 at our hospital. The internal fixation devices consisted of titanium plates and locking screws, securing 60 costal cartilage injury sites. Injuries were classified based on the fixation location: costal cartilage-costal cartilage (22 sites), bone (sternum, rib)- costal cartilage (24 sites), and bone (sternum)- costal cartilage-bone (rib) (14 sites). Follow-ups at 1, 3, 6, and 12months postoperatively included CT assessments to evaluate injury healing and the presence of displacement or screw loosening. The average lengths of the titanium plates used for the three different fixation positions were 6, 7, and 10 holes, respectively, with at least two locking screws securing each end. The maximum follow-up period was 90months, with 6 cases lost to follow-up (3 at 1month postoperatively, affecting 4 fixation sites, and 3 at 3months postoperatively, affecting 6 fixation sites). Excluding these cases, all fixed costal cartilage injuries healed without nonunion or displacement, with two instances of screw loosening observed at 1month postoperatively. Titanium plate fixation with locking screws is a safe and effective method for treating costal cartilage injuries, with all patients showing good injury healing.

Biomechanical Evaluation of Clival Screw Fixation for Occipitocervical Instablity: A Finite Element Analysis.

The clivus is trapezoidal in shape with uneven bone structure, the optimal number and position of screws for clival fixation are not clear. Therefore, this study aims to explore the optimization clival screw fixation method for occipitocervical instability using finite element analysis. Seven finite element models were developed to evaluate biomechanical properties of clival screw fixation for treating occipitocervical stability, including (i) one clival screw fixation A1 and A2 models; (ii) two clival screws fixation B1 and B2 models; (iii) three clival screws fixation C1 and C2 models; (iv) four clival screws fixation D1 model. Loads of 1.5 Nm were applied to the model fRoM different directions to induce flexion, extension, lateral bending, and axial rotation movements. The regular triangle C1 type three clival screws fixation exhibited great stability, with RoM of 4.20° in flexion, 5.80° in extension, 0.85° in lateral bending, and 1.60° in axial rotation. The peak stress on the internal fixation devices were relatively low, with maximum screw stress of 194 MPa in flexion, 276 MPa in extension, 180 MPa in lateral bending, and 213 MPa in axial rotation; the maximum plate stress were 126, 554, 426, and 378 MPa, respectively. The areas with higher stress were mainly concentrated at the robust neck section of the plate. The triangular configuration of three clival screws fixation represented the optimized anterior occipitocervical fixation method through the clivus, offering superior biomechanical stability, lower stress on the devices and dispersed stress distribution in the occipitocervical region.

Finite element assessment of the biomechanical implications of various internal fixation techniques used in lumbar interbody fusion surgeries

Abstract The use of lumbar interbody fusion along with an internal fixation device is a common procedure for addressing conditions such as herniated lumbar discs and lumbar spondylolisthesis. As there are fewer comparative studies on the posterior lateral approach, this study can provide a reference for a new surgical approach and a more optimized fixation protocol for the patient; hence, the following study is done. Accurate reconstruction of vertebral geometry and simulation of soft tissues enables the simulation of the implant’s positioning and configuration, as well as its impact on the surrounding tissues, throughout the surgical procedure. The fixation stage and intervertebral stresses, the disc stresses in neighboring segments, and the differences in mobility between stages were compared separately in each model. The total lumbar spine activity during forward flexion, backward extension, lateral bending, and twisting was reduced in Groups A, B, C, and D compared to the intact model. In addition, Group A generally had the least range of motion. As a result, patients in Group A had a more stable spine with a lower likelihood of degeneration.

Using additive manufacturing for craniocervical reconstruction in traditionally challenging cases.

Retrospective case series. The aim of this study was to evaluate the clinical outcomes and effectiveness of using 3D printed implants in upper cervical spine and occipitocervical junction surgery. C2 primary tumor patients who required axial en bloc resection and other patients who required partial bone decompression using customized 3D printed implants or fixation devices for surgery were included. Evaluate the stability and surgical outcomes of 3D printed implants through perioperative and follow-up period. Five tumor patients underwent reconstruction using customized 3D printed artificial vertebral bodies, while another five patients with atlantoaxial joint dislocation underwent reduction and decompression using customized 3D printed internal fixation devices. The postoperative imaging results showed that the 3D printed structures had good immediate stability and had no signs of displacement or subsidence. Follow up showed that all five cases of vertebral body reconstruction had achieved fusion. Only one patient died one month after surgery due to infection and respiratory difficulties. Other patients showed excellent improvement in neurological function in follow up. The use of 3D printed implants in surgery involving the occipitocervical area is a feasible and reliable alternative choice. It is a valuable attempt for complex atlantoaxial dislocation that cannot be treated with conventional instruments. 3D printed implants can improve the safety and accuracy of surgery, provide good immediate stability, have a low incidence of subsidence, fewer related complications during the follow-up period.

Efficacy of four internal fixation devices on femoral neck fractures in young adults: A systematic review and network meta-analysis.

The primary treatment of femoral neck fracture in young adults is internal fixation. The high complication rate after femoral neck fracture greatly affects the life of patients. There are many internal fixation devices for femoral neck fracture, but each has its advantages and disadvantages. Our aim was to determine the best internal fixation for young people with femoral neck fractures. We searched 5 databases from January, 2016 to December, 2023. Randomized controlled trials and cohort studies that met the inclusion criteria were assessed for quality using the RoB.2 and ROBINS-I scales, respectively. The network meta-analysis was conducted within a Bayesian framework utilizing a random effect model. Data analysis was performed using the "multinma" package within the R 4.2.0 software. A network meta-analysis of 34 studies involving 2291 patients was conducted. Results indicated that the inverted triangular cannulated screws demonstrated the lowest intraoperative bleeding volume (surface under the cumulative ranking curve [SUCRA] = 0.8732) based on the SUCRA. The medial buttress plate (MBP) exhibited superior efficacy in improving the Harris hip score (SUCRA = 0.8465), reducing complications (SUCRA = 0.9251), and accelerating fracture healing time (SUCRA = 0.8111). Additionally, the femoral neck system was ranked highest in terms of operation time (SUCRA = 0.7749) and femoral neck shortening (SUCRA = 0.7933). This network meta-analysis findings indicated that MBP resulted in superior postoperative hip function, reduced complication rate, faster fracture healing time. Considering the good physical condition of young adults, surgeon may consider utilizing MBP to achieve improved postoperative outcomes.

Case series study and finite element analysis of a new cervicothoracic fixation device

ObjectiveTo introduce a specialized device designed for the fixation of the cervical-thoracic spine and describe its surgical installation, finite element analysis, and clinical outcomes.MethodsA finite element model of the C6-T1 segment was developed and validated, and simulations of subtotal resection of anterior cervical vertebrae, artificial vertebrae placement, and titanium plate fixation were performed. The model was subjected to a 75 N load to simulate the weight of the head and a 1 N·m force to simulate flexion, lateral bending, and axial rotation. The analysis focused on range of motion, total stress, stress in the artificial vertebrae, and stress in the device. The clinical outcomes were evaluated in a retrospective case series of 140 patients with cervical spine fractures.ResultsUnder the same loading conditions, the maximum stresses on specialized anatomical and biomechanical devices for the fixation of the cervicothoracic segment of the spine during neutral, forwards flexion, backwards extension, left lateral bending, right lateral bending, left rotation, right rotation and other working conditions were 25.097 MPa, 149.480 MPa, 64.150 MPa, 67.804 MPa, 72.754 MPa, and 117.98 MPa, respectively. And, the maximum ROMs were 2.230 mm, 5.585 mm, 4.682 mm, 3.184 mm, 3.061 mm, 4.451 mm, and 4.645 mm. Compared with those in the preoperative period, the patients’ CL, OPCL, UCL, LCL, UROM, LROM, VAS score, NDI score, JOA score, intervertebral space height at the injured segment, cervical anterior kyphosis angle, Cobb angle, vertebral displacement, ASIA grade, fracture classification, and vertebral displacement improved (P < 0.05). Sixty-two patients had dysphagia, and 3 patients experienced leakage of cerebrospinal fluid.ConclusionThe design of the new cervicothoracic internal fixation device conforms to the anatomical structure of the cervicothoracic spine, which can provide immediate stability, better screw placement and adequate bone grafting, and reduce the risk of complications. Despite some disadvantages, it is a good device for segmental fixation of the cervical and thoracic spine.

Causes of Failure of Subtrochanteric Fracture Fixation, Systematic Review and Meta-Analysis

Abstract Background Subtrochanteric (ST) femoral fractures is defined as fractures of proximal femoral shaft that is located within 5 cm of the lesser trochanter. Any internal fixation device for trochanteric fractures is subject to significant concentrated bending stresses, leading to implant fatigue and fixation failure. Fixation of sub-trochanteric femoral fracture is considered a critical challenge. Objective To assess causes of failure of sub-trochanteric fracture fixation. Methods This meta-analysis study included 12 papers which included 999 patients, fixation failed in 163 patients. The included studies mentioned approximately 7 causes for fixation failure which included deep infection (in 2 studies), delayed union (in 2 studies), non-union (in 6 studies), screw cut-out (in 3 studies), Poor reduction (in 3 studies), implant breakage (in 4 studies) and varsus deformity /malrotation (in 3 studies). Results This study included 12 studies recruited 999 patients with sub- trochanteric femoral fracture, fixation was failed in 163 patients. The incidence of sub-trochanteric fixation failure was 17% in all included studies 62% of patients with fixation failure were smokers The incidence of fixation failure after intramedullary fixation was lower than after extra-medullary fixation. The incidence of fixation failure after open surgery increases 2.41 times compared with closed surgery. The incidence of fixation failure was higher in patients with post- operative hip varus compared with patients without post-operative hip varus. Conclusion The incidence of sub-trochanteric fixation failure was 17%. The causes for fixation failure included smoking, poor reduction, nonunion, implant breakage, screw cutout, varus deformity, extra-medullary nailing.

Antibiotic-Loaded Hydrogel for the Treatment of Lower-Limb Fracture-Related Infections: A Single Center's Multidisciplinary Experience.

A fracture-related infection (FRI) is a severe complication of an orthopedic trauma, often leading to challenging treatments and poor outcomes. The surgical strategies are typically categorized into one-stage or two-stage procedures, with the use of systemic and local antibiotics being crucial for infection management. This study assessed the efficacy of an antibiotic-loaded hydrogel (ALH) applied over the internal fixation devices for treating FRIs, comparing the outcomes between the one-stage (OS) and two-stage (TS) reconstructions. This retrospective study included 17 patients with an FRI treated using the ALH at a single center. The patients were divided into OS and TS reconstruction groups. The data on demographics, surgical procedures, antibiotic regimens, and outcomes were collected. The primary and secondary outcomes included the infection cure rate, bone union, complications, and reoperation rates. Among the 17 patients (mean age 48.5 years, 16 males), infections were predominantly in the tibia, with 12 chronic and 5 acute cases. Seven patients had monomicrobial infections, and nine had multidrug-resistant pathogens. No significant differences were found between the OS and TS groups in terms of the infection cure rate, bone union, or complications. One patient in the OS group experienced an infection recurrence, and bone healing was achieved in all but one case. Additional complications included delayed wound closure in two cases and implant failure in one case, requiring a reoperation. The ALH demonstrated potential as an effective local antibiotic treatment for FRIs, particularly in the one-stage reconstructions, allowing for a safe application of internal fixation devices. However, further research with larger sample sizes and longer follow-ups is needed to validate these findings.

Assessing the Impact of Nicotine Dependence on 90-Day Major Complications and 2-Year Hardware Outcomes in Open Reduction and Internal Fixation of the Distal Radius Fracture.

This study aims to assess the impact of nicotine dependence on both 90-day major postoperative outcomes and 2-year implant-related outcomes in patients undergoing open reduction internal fixation (ORIF) for distal radius fractures. We queried TriNetX, a national research database that provides real-time access to deidentified medical records, for patients of all ages who underwent an ORIF of the distal radius (Current Procedural Technology codes 25607, 25608, 25609) between 2001 and 2021. Patients were categorized by nicotine dependence history (International Classification of Diseases, Tenth Revision code: F17), with groups 1:1 propensity matched for age, sex, race, ethnicity, body mass index, type 2 diabetes, hypertension, cerebrovascular disease, and chronic obstructive pulmonary disease. The primary analysis examined major postoperative complications within 90 days, while the secondary analysis assessed hardware-related issues within 2 years. Risk ratios and 95% confidence intervals were generated for each outcome. Of 62 137 patients treated with distal radius ORIF, 7764 had nicotine dependence, and 54 373 did not. Each group comprised 7591 patients after 1:1 matching. Nicotine dependence was associated with increased risk of skin infections, sepsis, and wound disruption in the 90-day postoperative period (P < .001). Within the 2-year postoperative period, nicotine dependence was associated with increased risk of mechanical complication of internal fixation device (P < .001), nonunion (P < .01), and surgical intervention for nonunion (P = .009). Nicotine dependence is associated with increased risk of infection, sepsis, wound disruption within 90 days, and hardware complication, nonunion, and nonunion repair at 2 years. These data emphasize the importance of nicotine counseling by treating surgeons.

The evolution and practice on design concepts of internal fixation devices for intertrochanteric femur fractures

Surgical treatment has been established as the standard method for the treatment of intertrochanteric fractures in the elderly. The design of internal fixation devices has become the key to improve surgical outcomes and reduce postoperative complications. Centered on optimizing biomechanical performance and minimally invasive implantation, coupled with continuous material improvements, the design philosophy of internal fixation devices has also been constantly evolving. There have been several milestone advancements, such as the transition from eccentric fixation to central fixation, the adoption of sliding compression fixation, the replacement of traditional screws with spiral blades, and the shift from single to double (combination) nails. However, the incidence of internal fixation-related complications has remained at a relatively high level of 5% to 10%, without significant breakthroughs. Increasing evidence suggests that in-depth analysis of the anatomy, physiological mechanisms, and mechanical transmission characteristics of the proximal femur can help elucidate the root causes of internal fixation failures. Based on this, the proximal femoral bionic nail (PFBN) has emerged as a new design concept. By fully mimicking the anatomical, mechanical, and biological characteristics of the proximal femur, the PFBN can regulate the local mechanical environment, providing a revolutionary solution and a new approach for the treatment of proximal femoral fractures. This innovative design also has the potential to drive the paradigm shift in the treatment strategies of other fractures.

Oblique Dorsiflexion Osteotomy of the Distal Tibia for Fixed Ankle Equinus: Surgical Technique.

There are significant challenges in the treatment of a severe rigid ankle equinus caused by a flat-topped talus, arthrogryposis, burn sequelae, or extensive scarring. Conventional approaches, such as soft tissue releases, often fail due to joint incongruence or compromised soft tissues, thereby necessitating supramalleolar osteotomies. The classic transverse supramalleolar osteotomy (TSO) of the distal tibia can lead to secondary anterior translation of the centre of rotation of the ankle and alters mechanical and anatomical axes. An alternative technique involves an oblique closing wedge osteotomy of the distal tibia, with a fulcrum near the ankle joint. This technical note delineates the planning parameters and procedural steps for the oblique dorsiflexion osteotomy of the distal tibia (ODODT). Using an anterior approach to the distal tibia, the "alpha angle," which determines the size of the closing wedge required for the foot to be plantigrade, is resected with a fulcrum at the most posterior part of the ankle joint, ensuring that the posterior cortex remains intact. The inclination of this resected wedge is planned preoperatively and is referred to as the "beta angle." This aims to equalise the lengths on both sides of the osteotomy. For osteotomy fixation, 2 or 3 cannulated screws in lag mode are employed. Postoperatively, a short cast boot is used for 6 weeks. The ODODT is a salvage solution for severe rigid ankle equinus when first-line foot and ankle procedures are impractical due to tibiotalar incongruence or poor soft tissues. Advantages include minimal translation of the centre of rotation of the ankle, excellent stability when the posterior cortex remains intact, avoidance of large internal fixation devices, and cost-effectiveness, making it suitable for low-resource settings. Olleac R, Farfan F, Acosta L, et al. Oblique Dorsiflexion Osteotomy of the Distal Tibia for Fixed Ankle Equinus: Surgical Technique. Strategies Trauma Limb Reconstr 2024;19(2):104-110.

Deep learning-based automated angle measurement for flatfoot diagnosis in weight-bearing lateral radiographs

This study aimed to develop and evaluate a deep learning-based system for the automatic measurement of angles (specifically, Meary’s angle and calcaneal pitch) in weight-bearing lateral radiographs of the foot for flatfoot diagnosis. We utilized 3960 lateral radiographs, either from the left or right foot, sourced from a pool of 4000 patients to construct and evaluate a deep learning-based model. These radiographs were captured between June and November 2021, and patients who had undergone total ankle replacement surgery or ankle arthrodesis surgery were excluded. Various methods, including correlation analysis, Bland–Altman plots, and paired T-tests, were employed to assess the concordance between the angles automatically measured using the system and those assessed by clinical experts. The evaluation dataset comprised 150 weight-bearing radiographs from 150 patients. In all test cases, the angles automatically computed using the deep learning-based system were in good agreement with the reference standards (Meary’s angle: Pearson correlation coefficient (PCC) = 0.964, intraclass correlation coefficient (ICC) = 0.963, concordance correlation coefficient (CCC) = 0.963, p-value = 0.632, mean absolute error (MAE) = 1.59°; calcaneal pitch: PCC = 0.988, ICC = 0.987, CCC = 0.987, p-value = 0.055, MAE = 0.63°). The average time required for angle measurement using only the CPU to execute the deep learning-based system was 11 ± 1 s. The deep learning-based automatic angle measurement system, a tool for diagnosing flatfoot, demonstrated comparable accuracy and reliability with the results obtained by medical professionals for patients without internal fixation devices.

Research Progress on the Treatment of Geriatric Intertrochanteric Femur Fractures with Proximal Femur Bionic Nails (PFBNs).

Intertrochanteric femur fracture is the most common hip fracture in elderly people, and the academic community has reached a consensus that early surgery is imperative. Proximal femoral nail anti-rotation (PFNA) and InterTan are the preferred internal fixation devices for intertrochanteric femur fractures in elderly individuals due to their advantages, such as a short lever arm, minimal stress shielding, and resistance to rotation. However, PFNA is associated with complications such as nail back-out and helical blade cut-out due to stress concentration. As a new internal fixation device for intertrochanteric femur fractures, the proximal femoral biodegradable nail (PFBN) addresses the issue of nail back-out and offers more stable fracture fixation, a shorter lever arm, and stress distribution compared to PFNA and InterTan. Clinical studies have shown that compared to PFNA, PFBNs lead to faster recovery of hip joint function, shorter non-weight-bearing time, and faster fracture healing. This article provides a literature review of the structural characteristics, biomechanical analysis, and clinical studies of PFBNs, aiming to provide a theoretical basis for the selection of internal fixation devices for the treatment of intertrochanteric femur fractures in elderly patients and to improve the quality of life of patients during the postoperative period.

Biomechanical analysis of various internal fracture fixation devices used for treating femoral neck fractures: A comparative finite element analysis

IntroductionSeveral internal fixation devices are available for treating Pauwels type I, II and III femoral neck fractures. The present study compared various fixation implants for all Pauwels fracture types using a CT-based subject-specific finite element model of the femur and determined the most effective implant for each fracture type. Materials and MethodsThe analysis included four different configurations of cannulated screw models, Femoral Neck System, Dynamic Hip Screw and Dynamic Condylar Screw (with and without anti-rotational screw). Ti-alloy was considered as the implant material. Heterogeneous bone material property was assigned based on CT grey value. Frictional contact was assumed in the contact interfaces. Peak loading corresponding to normal walking and stair-climbing were considered. Equivalent strain in bone, equivalent stress in the implants, femoral head deformation and rotation, micromotion in the contact interfaces, and strain-shielding in bone were evaluated for each implanted model. ResultsStresses generated in the implants were within the yield limit of the implant material. In Pauwels I and II, the micromotion predicted at the contact regions in all the implanted models was within 100 µm, which is suitable for bone integration. However, in Pauwels III fracture, most of the implanted models other than DHS with AR-screw model exhibited micromotion of more than 150 µm in the contact regions, which is expected to inhibit bone growth. ConclusionsThe DHS with AR-screw implanted model was identified as the most effective in treating Pauwels I and III fractures. However, for Pauwels type II, DCS with an AR-screw implant was deemed superior to the other configurations.

Quantitative Analysis of Primary Compressive Trabeculae Distribution in the Proximal Femur of the Elderly.

As osteoporosis progresses, the primary compressive trabeculae (PCT) in the proximal femur remains preserved and is deemed the principal load-bearing structure that links the femoral head with the femoral neck. This study aims to elucidate the distribution patterns of PCT within the proximal femur in the elderly population, and to assess its implications for the development and optimization of internal fixation devices used in hip fracture surgeries. This is a retrospective cohort study conducted from March 2022 to April 2023. A total of 125 patients who underwent bilateral hip joint CT scans in our hospital were enrolled. CT data of the unaffected side of the hip were analyzed. Key parameters regarding the PCT distribution in the proximal femur were measured, including the femoral head's radius (R), the neck-shaft angle (NSA), the angle between the PCT-axis and the head-neck axis (α), the distance from the femoral head center to the PCT-axis (δ), and the lengths of the PCT's bottom and top boundaries (L-bottom and L-top respectively). The impact of gender differences on PCT distribution patterns was also investigated. Student's t-test or Mann-Whitney U test were used to compare continuous variables between genders. The relationship between various variables was investigated through Pearson's correlation analysis. PCT was the most prominent bone structure within the femoral head. The average NSA, α, and δ were 126.85 ± 5.85°, 37.33 ± 4.23°, and 0.39 ± 1.22 mm, respectively, showing no significant gender differences (p > 0.05). Pearson's correlation analysis revealed strong correlations between α and NSA (r = -0.689, p < 0.001), and R and L-top (r = 0.623, p < 0.001), with mild correlations observed between δ and NSA (r = -0.487, p < 0.001), and R and L-bottom (r = 0.427, p < 0.001). Importantly, our study establishes a method to accurately localize PCT distribution in true anteroposterior (AP) radiographs of the hip joint, facilitating precise screw placement in proximal femur fixation procedures. Our study provided unprecedented insights into the distribution patterns of PCT in the proximal femur of the elderly population. The distribution of PCT in the proximal femur is predominantly influenced by anatomical and geometric factors, such as NSA and femoral head size, rather than demographic factors like gender. These insights have crucial implications for the design of internal fixation devices and surgical planning, offering objective guidance for the placement of screws in hip fracture treatments.

Bone Incorporation of a Poly (L-Lactide-Co-D, L-Lactide) Internal Fixation Device in a Rat's Tibia: Microtomographic, Confocal LASER, and Histomorphometric Analysis.

This study evaluated the bone incorporation process of a screw-shaped internal fixation device made of poly (L-lactide-co-D, L-lactide) (PLDLLA). Thirty-two male Wistar rats received 32 fixation devices (2 mm × 6 mm) randomly assigned to either the right or left tibia and one implant in each animal. After 7, 14, 28, and 42 days, the rats were euthanized and the specimens were subjected to microtomographic computed tomography (microCT) and histomorphometric analyses to evaluate bone interface contact (BIC%) and new bone formation (NBF%) in cortical and cancellous bone areas. The animals euthanized on days 28 and 42 were treated with calcein and alizarin red, and confocal LASER microscopy was performed to determine the mineral apposition rate (MAR). Micro-CT revealed a higher percentage of bone volume (p < 0.006), trabecular separation (p < 0.001), and BIC in the cortical (p < 0.001) and cancellous (p = 0.003) areas at 28 and 42 days than at 7 and 14 days. The cortical NBF at 42 days was greater than that at 7 and 14 days (p = 0.022). No statistically significant differences were observed in cancellous NBF or MAR at 28 and 42 days. Based on these results, it can be seen that the PLDLLA internal fixation device is biocompatible and allows new bone formation around the screw thread.

Application of microwave ablation assisted degradation therapy in surgical treatment of intramedullary chondrosarcoma of extremities

AimClinical diagnosis and surgical treatment of chondrosarcoma (CS) are continuously improving. The purpose of our study is to evaluate the effectiveness of microwave ablation (MWA) assisted degradation therapy in the surgical treatment of intramedullary chondrosarcoma of the extremities, to provide a new reference and research basis for the surgical treatment of CS.MethodsWe recruited 36 patients with intramedullary CS who underwent MWA assisted extended curettage. Preoperative patient demographics and clinical data were recorded. Surgery was independently assisted by a medical team. Patients were followed up strictly and evaluated for oncological prognosis, radiological results, limb joint function, pain, and complications.ResultsWe included 15 men and 21 women (mean age: 43.5 ± 10.1). The average length of the lesion was 8.1 ± 2.5 cm. Based on preoperative radiographic, clinical manifestations, and pathological results of puncture biopsy, 28 patients were preliminarily diagnosed with CS-grade I and eight patients with CS-grade II. No recurrence or metastasis occurred in the postoperative follow-up. The average Musculoskeletal Tumor Society score was 28.8 ± 1.0, significantly better than presurgery. Secondary shoulder periarthritis and abduction dysfunction occurred in early postoperative stage CS of the proximal humerus in some, but returned to normal after rehabilitation exercise. Secondary bursitis occurred at the knee joint in some due to the internal fixation device used in treatment; however, secondary osteoarthritis and avascular necrosis of the femoral head were not observed. Overall, oncological and functional prognoses were satisfactory.ConclusionsThe application of MWA assisted degradation therapy in intramedullary CS can achieve satisfactory oncology and functional prognosis, providing a new option for the limited treatment of CS.

Biomechanical analysis of fixation methods for bone flap repositioning after lateral orbitotomy approach: A finite element analysis

ObjectiveIn ophthalmic surgery, different materials and fixation methods are employed for bone flap repositioning after lateral orbitotomy approach (LOA), yet there is no unified standard. This study aims to investigate the impact of different fixation strategies on orbital stability through Finite Element Analysis (FEA) simulations of the biomechanical environment for orbital rim fixation in LOA. MethodsA Finite Element Model (FEM) was established and validated to simulate the mechanical responses under various loads in conventional lateral orbitotomy approach (CLOA) and deep lateral orbital decompression (DLOD) using single titanium plate, double titanium plates, and double absorbable plates fixation methods. The simulations were then validated against clinical cases. ResultsUnder similar conditions, the maximum equivalent stress (MES) on titanium alloy fixations was greater than that on absorbable plate materials. Both under static and physiological conditions, all FEM groups ensured structural stability of the system, with material stresses remaining within safe ranges. Compared to CLOA, DLOD, which involves the removal of the lateral orbital wall, altered stress conduction, resulting in an increase of MES and maximum total deformation (MTD) by 1.96 and 2.62 times, respectively. Under a horizontal load of 50 N, the MES in FEM/DLOD exceeded the material's own strength, with an increase in MES and MTD by 3.18 and 6.64 times, respectively, compared to FEM/CLOA. Under a vertical force of 50 N, the MES sustained by each FEM was within safe limits. Bone flap rotation angles remained minimally varied across scenarios. During follow-up, the 12 patients validated in this study did not experience complications related to the internal fixation devices. ConclusionUnder static or physiological conditions, various fixation methods can effectively maintain stability at the orbitotomy site, and absorbable materials, with their smoother stress transmission properties, are more suited for application in CLOA. Among titanium plate fixations, single titanium plates can better withstand vertical stress, while double titanium plates are more capable of handling horizontal stress. Given the change in the orbital mechanical behavior due to DLOD, enhanced fixation strength should be considered for bone flap repositioning.

Reconstruction of gap non-union tibia with composite use of extramedullary fixation and bone transport by monorail fixator: a prospective case series.

Non-union is a complex, multifactorial orthopaedic problem that requires multiple treatment modalities for its management. It can result from infection, segmental bone loss, soft-tissue loss, and associated host factors. External fixators as management of gap non-union are bulky and give rise to a number of complications In our study, we have described a technique where we have used extramedullary fixation in the form of a tibial locking plate and transportation of part of the tibial bone after corticotomy by a monorail fixator. The procedure was done in two stages where internal and external fixation was done after creating a gap at the non-union site. The bone was transported after corticotomy and fixed to the internal fixation device in the second stage. The external fixator was removed in the second stage and the patient was then followed up till the bony union. The evaluation was done by functional and radiological assessment along with the complications noted with the described procedure. Ten patients were enrolled in the study with a mean age of 33 years. The mean age of the patients was 33.7 ± 11.32 years with a mean size of the defect was 4.8 ± 1.7 cm. At 30 weeks out of nine patients, three patients had excellent and six had good functional results on the Association of Surgeons for Application and Methodology of Ilizarov (ASAMI) scale. The composite Musculoskeletal Tumor Society (MSTS) score was 76.66 % at the end of 30 weeks of follow-up. The mean time of consolidation was 134.4 days, whereas the mean union time was 145 days from index surgery. Ankle stiffness was the most common complication affecting 50% of the patients. Following closely was pin tract infection, which was present in 40% of the patients. According to Paley's classification, there were 11 obstacles, two problems and none were true complications. The integrated fixation is both safe and effective and has the advantage of early removal of the external fixator and a low complication rate as compared to use of a bulky conventional fixator alone. Moreover, it gives protection to the regenerated bone for a long period. So, this technique can be recommended for the management of segmental tibial defects.