Biomaterials for bone defect repair: Types, mechanisms and effects.

Bone defects or bone discontinuities caused by trauma, infection, tumours and other diseases have led to an increasing demand for bone grafts and biomaterials. Autologous bone grafts, bone grafts with vascular tips, anastomosed vascular bone grafts and autologous bone marrow components are all commonly used in clinical practice, while oversized bone defects require the use of bone tissue engineering-related biomaterials to repair bone defects and promote bone regeneration. Currently, inorganic components such as polysaccharides and bioceramics, as well as a variety of bioactive proteins, metal ions and stem cells can be loaded into hydrogels or 3D printed scaffold materials to achieve better therapeutic results. In this review, we provide an overview of the types of materials, applications, potential mechanisms and current developments in the repair of bone defects.

How to remove a well-fixed metaphyseal sleeve in revision knee arthroplasty: A step-by-step surgical procedure.

BACKGROUND: The rising incidence and complexity of revision knee arthroplasty has led to an increase in the use of metaphyseal reconstruction systems. One of the most widely used systems are metaphyseal sleeves as they have demonstrated excellent long-term survival. However, there is concern about the possible difficulty of extracting a sleeve if it were necessary, as no known procedures have yet been validated. METHODS: We examined the outcomes of removing 23 well-integrated metaphyseal sleeves using the same systematized technique. RESULTS: All sleeves were extracted without any intraoperative complications. Four subjects required an osteotomy to complete the extraction, while 62% of the sample were found to have an AORI IIB defect. All cases were successfully reconstructed with a new metaphyseal fixation, implanting a new sleeve in 38% of subjects compared with cones in the remaining 62%. CONCLUSIONS: The technique described here produced successful, reproducible outcomes for the removal of integrated metaphyseal sleeves with minimal bone loss and no intraoperative complications.

Advances in 3D Printing of Highly Bioadaptive Bone Tissue Engineering Scaffolds.

The number of patients with bone defects caused by trauma, bone tumors, and osteoporosis has increased considerably. The repair of irregular, recurring, and large bone defects poses a great challenge to clinicians. Bone tissue engineering is emerging as an appropriate strategy to replace autologous bone grafting in the repair of critically sized bone defects. However, the suitability of bone tissue engineering scaffolds in terms of structure, mechanics, degradation, and the microenvironment is inadequate. Three-dimensional (3D) printing is an advanced additive-manufacturing technology widely used for bone repair. 3D printing constructs personalized structurally adapted scaffolds based on 3D models reconstructed from CT images. The contradiction between the mechanics and degradation is resolved by altering the stacking structure. The local microenvironment of the implant is improved by designing an internal pore structure and a spatiotemporal factor release system. Therefore, there has been a boom in the 3D printing of personalized bone repair scaffolds. In this review, successful research on the preparation of highly bioadaptive bone tissue engineering scaffolds using 3D printing is presented. The mechanisms of structural, mechanical, degradation, and microenvironmental adaptations of bone prostheses and their interactions were elucidated to provide a feasible strategy for constructing highly bioadaptive bone tissue engineering scaffolds.

A novel pneumatic drill for bone biopsy under MRI imaging.

PURPOSE: Bone biopsies are currently conducted under computed tomography (CT) guidance using a battery-powered drill to obtain tissue samples for diagnosis of suspicious bone lesions. However, this procedure is suboptimal as images produced under CT lack soft tissue discrimination and involve ionizing radiation. Therefore, our team developed an MRI-safe pneumatic drill to translate this clinical workflow into the MR environment, which can improve target visualization and eliminate radiation exposure. We compare drill times and quality of samples between the 2 drills using animal bones. METHODS: Five porcine spare rib bones were obtained from a butcher shop. Each bone was drilled twice using the Arrow OnControl battery-powered drill and twice using our pneumatically actuated drill. For this study, we used an 11-gauge bone biopsy needle set with an internal core capturing thread. A stopwatch recorded the overall time of drilling for each specimen obtained. RESULTS: All 20 samples collected contained a high-quality inner core and cortex. The total average time for drilling with the pneumatic drill was 8.5 s (+ / - 2.5 s) and 7.1 s (+ / - 1.4 s) with the standard battery-powered drill. CONCLUSION: Both drills worked well and were able to obtain comparable specimens. The pneumatic drill took slightly longer, 1.39 s on average, but this extra time would not be significant in clinical practice. We plan to use the pneumatic drill to enable MRI-safe bone biopsy for musculoskeletal lesions. Biopsy under MRI would provide excellent lesion visualization with no ionizing radiation.

Segmenting/Pre-Processing Data from Bone Screw Thread-Stripping Tests.

Bone screws must be appropriately tightened to achieve optimal patient outcomes. If over-torqued, the threads formed in the bone may break, compromising the strength of the fixation; and, if under-torqued, the screw may loosen over time, compromising the stability. Previous work has proposed a model-based system to automatically determine the optimal insertion torque. This system consists of a reverse-modelling step to determine strength, and a forward modelling step to determine maximum torque. These have previously been tested in isolation, however future work must test the combined system. To do so, the data must be segmented and pre-processed. This was done based on specific features of the recorded data. The methodology was tested on 50 screw-insertion data sets across 5 different materials. With the parameters used, all data sets were correctly segmented. This will form a basis for the further processing of the data and validating the combined systemClinical relevance: The system for torque limit determination must be tested in its entirety to properly asses its performance. This paper discusses some of the steps required to pre-process the data to make this assessment. If successful, this system may improve patient outcomes in orthopaedic surgery.

Anchoring flap suture technique to repair a wound with exposed bone after hip disarticulation: a case report and brief review of the literature.

BACKGROUND: In specific clinical scenarios characterized by poor tissue conditions surrounding a wound, achieving stable flap fixation with standard sutures can be challenging. The anchoring flap suture technique, which is commonly used for soft tissue-to-bone attachment in cases of injury, may be an alternative and effective approach. CASE REPORT: This report describes the successful application of the anchoring flap suture technique to repair a wound with exposed bone in a 39-year-old female patient. She presented with a 7% TBSA wound of the left trunk following hip disarticulation. After 4 operations, a wound with exposed iliac bone remained. Given the compromised condition of the tissues surrounding the exposed bone, the authors opted to anchor a local flap directly to the exposed bone. Steady flap fixation was achieved using the anchoring flap suture method, resulting in complete healing of that wound. Remarkably, no short- or long-term complications associated with the flap were observed. Three months after hospital discharge, the patient regained mobility, walking on 1 leg with the assistance of a 4-legged walker. CONCLUSION: The anchoring flap suture technique seems to be a reliable and effective treatment option, particularly in cases in which inadequate soft tissue precludes the use of traditional flap fixation using standard sutures.

Prospective evaluation of clinical and radiographic 10-year results of Fitmore short-stem total hip arthroplasty.

BACKGROUND: Short stems were introduced into total hip arthroplasty (THA) to preserve bone stock, to transmit more load to the proximal femur, and to enable minimal invasive approaches. This study is the first long-term study (with a follow-up of 10 years) of the survival as well as the clinical and radiographic outcomes of the Fitmore hip stem, a short curved uncemented stem. METHODS: In total, 123 Fitmore hip stems were prospectively evaluated. At the final 10-year follow-up, 80 Fitmore stems (78 patients: 30 female, 48 male) were eligible for evaluation. Clinical parameters were thigh pain, EQ-5D, Harris Hip Score (HHS) and Oxford Hip Score. Radiographic parameters were cortical hypertrophy (CH), bone condensation, cortical thinning, radiolucency, reactive lines, calcar rounding, calcar resorption, subsidence and varus/valgus position. RESULTS: After 10 years, there was a survival rate of 99% (1 revision because of aseptic stem loosening). HHS had improved from 59 to 94 and Oxford Hip Score from 22 to 43. CH rate after 1 year was 69% and after 10 years 74%. In the first year, radiolucency was found in 58% and in 17.5% after 10 years. Subsidence after 1 year was 1.6 ± 1.6 mm and 5.0 ± 3.1 mm after 10 years. CONCLUSIONS: The Fitmore hip stem showed a survival rate of 99% as well as good clinical and radiographic outcomes in the long-term follow-up of 10 years.

Evaluating and Comparing the Effectiveness of Nano-HA and HA + ß-TCP with A-PRF Clinically and Radiographically in the Treatment of Human Infrabony Defects.

AIM: To evaluate and compare the effectiveness of nanocrystalline hydroxyapatite (NcHA) with advanced platelet-rich fibrin (A-PRF) and hydroxyapatite-reinforced beta tricalcium phosphate (HA + ß-TCP) with A-PRF in the treatment of human infrabony defects clinically and radiographically using cone-beam computed tomography (CBCT). MATERIALS AND METHODS: There were a total of 28 defects, with 14 defects in the test and control groups, respectively. There were total 28 patients were involved in the study. The test group (group A) was treated with NHA and A-PRF, while the control group (group B) was treated with HA + ß-TCP and A-PRF. Bone defect fill was the primary result of the investigation. Periodontal pocket depth (PPD), R-CAL, papillary bleeding index (PBI), and PI were the secondary outcome. Clinical and radiographic measurements were recorded at baseline and 6 months postoperatively. RESULTS: No significant difference was observed between the two groups in terms of PPD reduction (4.64 ± 0.74 mm vs 4.07 ± 0.99 mm), clinical attachment loss (CAL) gain (4.64 ± 0.74 mm vs 3.92 ± 0.99 mm) and radiographic defect depth reduction (2.41 ± 0.32 mm vs 2.40 ± 0.27 mm) for test and control groups, respectively. CONCLUSION: At 6-month post-surgery, both treatment modalities demonstrated statistically significant improvements with regard to CAL gains, PPD reduction, and reduction in radiographic defect depth. CLINICAL RELEVANCE: The NcHA and HA + ß-TCP with A-PRF is a novel material used in the treatment of infrabony defect for periodontal regeneration. The NcHA and HA + ß-TCP with A-PRF need to consider biomaterials for bone defect fill.

Supracondylar Apophysis of the Humerus: Rare Cause of High Compression of the Median Nerve / Apófise supracondilar do úmero: Causa rara de compressão alta do nervo mediano

Abstract Supracondylar apophysis (SA) is a bony prominence that originates from the anteromedial aspect of the distal humerus with a lower projection and which, although usually asymptomatic, due to the relationship with adjacent structures can cause symptoms. We describe the case of a 42-year-old woman with pain complaints radiating from her elbow to her hand, with 6 months of evolution. On objective examination, the patient had a sensory deficit in the median nerve territory and decreased grip strength. Radiographs of the distal humerus were performed, in which a bone spike was visible, and magnetic resonance imaging showed thickening of the median nerve epineurium. Electromyography showed severe axonal demyelination of the median nerve proximal to the elbow. A median nerve compression caused by a SA was diagnosed. The patient underwent surgery and, 1 year after the operation, she had a complete clinical recovery. Supracondylar apophysis is a rare, but possible and treatable cause of high median nerve compression.

Resumo A apófise supracondilar (ASC) é uma proeminência óssea que tem origem na face anteromedial do úmero distal com projeção inferior e que, apesar de habitualmente assintomática, pela relação com as estruturas adjacentes pode causar sintomatologia. Descrevemos o caso de uma mulher de 42 anos, com queixas álgicas irradiadas do cotovelo à mão, com 6 meses de evolução. Ao exame objetivo, a paciente apresentava um déficit sensorial no território do nervo mediano e diminuição da força de preensão. Foram realizadas radiografias do úmero distal nas quais era visível uma espícula óssea, e na ressonância magnética era evidente o espessamento do epineuro do nervo mediano. A eletromiografia apresentou uma desmielinização axonal grave do nervo mediano proximal ao cotovelo. Foi diagnosticada uma compressão do nervo mediano por uma ASC. A paciente foi submetida à cirurgia e 1 ano pós-operatório apresentou recuperação clínica total. A ASC é uma causa rara, mas possível e tratável da compressão alta do nervo mediano.

VISTA Approach in Conjunction with Enamel Matrix Derivative, Corticocancellous Bone, and Connective Tissue Graft for Periodontal Defect Surgery: A Case Series.

The biggest challenge during periodontal regeneration in the anterior region is the prevention of soft tissue recession. Minimally invasive surgeries, particularly papilla preservation techniques and soft tissue augmentation, may significantly reduce such postoperative soft tissue recession. This article presents the vestibular incision subperiosteal tunnel access (VISTA) approach for periodontal regeneration in the anterior region. A subperiosteal tunnel prepared from a single vertical vestibular incision adjacent to the defect is used for debridement, application of enamel matrix derivative, defect grafting with corticocancellous tuberosity bone, and insertion of the connective tissue graft. Evaluation of six cases with up to 6 years of follow-up showed improvements in all clinical parameters. The probing pocket depth improved from 8.2 ± 0.75 mm initially to 2.7 ± 0.52 mm at follow-up, clinical attachment level improved from 8.5 ± 0.83 mm initially to 2.7 ± 0.52 mm at follow-up, and midfacial gingival recession of 1 mm at two sites was corrected. The papillae were stable at all sites, with an average distance of 4.8 mm from the incisal edge to the papilla tip. This technique seems to be a promising approach for achieving both esthetic and functional goals of periodontal regenerative surgery. However, experience in performing microsurgeries and harvesting tuberosity tissues may be a limitation.

Effect of drill quality on biological damage in bone drilling.

Bone drilling is a universal procedure in orthopaedics for fracture fixation, installing implants, or reconstructive surgery. Surgical drills are subjected to wear caused by their repeated use, thermal fatigue, irrigation with saline solution, and sterilization process. Wear of the cutting edges of a drill bit (worn drill) is detrimental for bone tissues and can seriously affect its performance. The aim of this study is to move closer to minimally invasive surgical procedures in bones by investigating the effect of wear of surgical drill bits on their performance. The surface quality of the drill was found to influence the bone temperature, the axial force, the torque and the extent of biological damage around the drilling region. Worn drill produced heat above the threshold level related to thermal necrosis at a depth equal to the wall thickness of an adult human bone. Statistical analysis showed that a sharp drill bit, in combination with a medium drilling speed and drilling at shallow depth, was favourable for safe drilling in bone. This study also suggests the further research on establishing a relationship between surface integrity of a surgical drill bit and irreversible damage that it can induce in delicate tissues of bone using different drill sizes as well as drilling parameters and conditions.

Experiments on physical ablation of long bone using microwave ablation; defining optimal settings using ex- and in-vivo experiments.

BACKGROUND: Improved survival of cancer patients leads to more skeletal metastatic lesions that need local therapies for tumor control and pain relief. Not all tumors are radiosensitive and alternative therapies are direly needed. Microwave ablation (MWA) is a technique for minimally invasive local tumor control by physical ablation. In soft tissue local temperature ablation is more common, but studies on bone tissue are limited. To ensure safe and effective treatment, studies on local tumor ablation in bone are needed. METHOD: Microwave ablation was performed on sheep bone, for both in- and ex-vivo settings. Both a slow-cooking MWA protocol (gradually increasing wattage in the first two minutes of ablation) and a fast-cooking protocol (no warm-up period) were used. Heat distribution through the bone during ablation was determined by measuring temperature at 10- and 15mm from the ablation probe (= needle). Ablation size after procedure was measured using nitro-BT staining. RESULTS: In-vivo ablations led to up to six times larger halos than ex-vivo with the same settings. Within both ex- and in-vivo experiments, no differences in halo size or temperature were found for different wattage levels (65W vs 80W). Compared to a fast cooking protocol, a two-minute slow cooking protocol led to increased temperatures and larger halos. Temperatures at 10- and 15mm distance from the needle no longer increased after six minutes. Halo sizes kept increasing over time without an evident plateau. CONCLUSION: Microwave ablation is technically effective for creating cell death in (sheep) long bone. It is recommended to start ablations with a slow-cooking period, gradually increasing the surrounding tissue temperature in two minutes from 40 to 90°C. Ex-vivo results cannot simply be translated to in-vivo.

[How I treat... a fracture of the coronoid apophysis, choice between conservative attitude and surgical treatment]. / Comment je traite...une fracture de l'apophyse coronoïde, entre attitude conservatrice et traitement chirurgical.

Fractures of the coronoid process are the rarest mandibular fractures and are mostly associated with other maxillofacial fractures. They are most often encountered in trauma. The CT-scanner is the gold standard for locating and characterizing this lesion. Although the diagnosis is made radiologically, clinical examination may reveal various symptoms specific to this fracture, which may appear frustrated when other facial fractures are associated. In most cases, conservative treatment by intermaxillary fixation is preferred. However, in specific cases, surgical intervention such as coronoidectomy or open reduction with osteosynthesis is indicated. The type of fracture, its location, the delay before its management, the clinic and the presence of associated fractures guide the therapeutic attitude. Surgical management must be followed by early and intensive physiotherapy to avoid zygomatico-coronoid ankylosis, the main complication of this fracture.

Les fractures de l'apophyse coronoïde sont les fractures mandibulaires les plus rares et majoritairement associées à d'autres fractures maxillo-faciales. Elles se rencontrent le plus souvent lors de traumatisme. Le CT-scanner est le gold standard pour localiser et caractériser cette lésion. Bien que le diagnostic soit radiologique, l'examen clinique peut révéler différents symptômes propres à cette fracture et qui peuvent paraître frustres lorsque d'autres fractures du massif facial y sont associées. Dans la majorité des cas, le traitement conservateur par fixation intermaxillaire est privilégié. Mais dans des indications précises, une intervention chirurgicale, comme une coronoïdectomie ou une réduction ouverte avec ostéosynthèse, est indiquée. Le type de fracture, sa localisation, le délai avant sa prise en charge, la clinique et la présence de fractures associées guident l'attitude thérapeutique. Une prise en charge chirurgicale doit être suivie de physiothérapie précoce et intensive pour éviter l'ankylose zygomatico-coronoïde, principale complication de cette fracture.

Bone cutting processes and removal behaviors in orthopedic surgery with an ultrasonic orthopedic scalpel.

Bone cutting is a common and important procedure in surgery. As a type of orthopedic instrument, ultrasonic orthopedic scalpels (UOSs) have been widely used due to their safety and convenience. Therefore, it is very important to have a deep understanding of the cutting process and the bone removal behavior of a UOS, to improve cutter design and complement the basic theory of the bone-cutting mechanism. However, few studies have focused on the characteristics of ultrasonic cutting. In this work, based on bone structure, the bone-cutting processes of a UOS were defined and the bone removal behavior in ultrasonic bone cutting was studied. In this study, it was believed that a direction of ultrasonic vibration different from that of the lamellar arrangement and collagen fibers would lead to different cutting characteristics. Based on this, the cutting modes were divided into four typical types. After examining and analyzing the crack propagation and chip formation of compact bone for the four cutting modes, the removal behaviors of ultrasonic bone cutting were defined. At the same time, the surface morphology indicated that there were significant differences in the surface damage for different cutting modes, which supported the idea that the bone removal behaviors were different for different modes. In addition, the force signals were analyzed and the results showed that there were differences in the cutting forces for different cutting modes. The static and dynamic components of the cutting forces were also analyzed. The study demonstrated the correlation between bone removal and the microscopic and submicroscopic structure of bone in ultrasonic cutting. These conclusions provided guidelines for analyzing bone tissue injuries caused by UOSs, improving the surgical process of bone cutting, optimizing the design of orthopedic instruments, and further complementing the basic theory of bone cutting.

Surgical Epicondylar Axis of the Knee and Its Relationship to the Axial Tibia Alignment in Knee Osteoarthritis: The Concept of Proximal Twist Tibia.

The proximal tibia and distal femur are intimately linked with the biomechanics of the knee and they are to be considered in total knee arthroplasty (TKA). The aim of the present study was to evaluate the proximal tibial torsion (PTT) in relation to surgical epicondylar axis (SEA) in a healthy cohort and a pathological cohort affected by knee osteoarthritis (OA). We retrospectively analyzed computed tomography of OA knee of 59 patients before they underwent TKA and nonarthritic knee of 39 patients as control. Posterior condylar angle (PCAn), femoral tibial torsion (SEA-proximal tibial condyle [PTC] and SEA-PTT), PTT (PTC-PTT and posterior condylar axes [PCAx]-PTC), and distance between tibial tuberosity and the trochlear groove (TT-TG) were measured. No differences were found for gender, age, TT-TG, and PCAn angles. Statistically significant differences were found for all the other angles considered. Significant correlation was found between tibial torsion and SEA-PTT angles, between PCAx-PTC and SEA-PTC, between SEA-PTT and SEA-PTC, and between PCAx-PTC and SEA-PTT. All measures, except TT-TG and PCAn angles, showed high validity (area under the curve [AUC] > 75%) in associating with OA, with SEA-PTT displaying the highest validity with an AUC of 94.38%. This is the first study to find significant differences in terms of proximal tibia geometry and anatomy between nonarthritic and OA knees. From our results, we reported that OA group was characterized by a greater internal rotation of tibia with respect to SEAs compared with control group. Since the design of the study cannot evaluate a cause-effect relationship, further studies need to be performed to assess the potential implications of these anatomic differences for knee OA and arthroplasty surgeries.

More than a feeling?-Overruling the preoperatively templated offset option leads to a minor offset increase in short stem total hip arthroplasty.

PURPOSE: Short stems are increasingly used in total hip arthroplasty (THA) because of advantages in bone and soft tissue preservation and reconstruction of hip geometry. Digital templating is essential in determining the correct offset option and stem size in THA. However, the preoperative template sizes might be intraoperatively overruled. PATIENTS AND METHODS: We evaluated the effect of intraoperative overruling of the preoperatively templated offset option of a short curved stem on hip offset, leg length, implant positioning, and femoral canal fill index. The overruling was performed in case of intraoperative instability, telescoping, or both. A series of 1052 consecutive THAs with a cementless short curved stem and press-fit cup was retrospectively screened. One hundred patients with unilateral THA and a contralateral native and morphologically healthy hip as a reference met the inclusion criteria. Measurements were carried out on preoperative and 3 months anterior-posterior postoperative radiographs. Patients were divided according to the overruling by offset option or stem size. RESULTS: Hip offset was increased in all groups, but only with significant increase if an offset option + 1 was used intraoperatively (p = 0.025). LLD was restored without significance in all groups (p = 0.323; p = 0.157). CONCLUSION: Intraoperative overruling of the preoperative digital template in cementless short stem total hip arthroplasty results in an increase of hip offset compared to a contralateral healthy hip. However, the increase is marginal and clearly under 5 mm compared to the contralateral healthy hip.

The Impact of Implantoplasty in Regenerated and Nonregenerated Treatment Modalities in Peri-implantitis: A Systematic Review and Meta-analysis.

PURPOSE: To investigate the impact of implantoplasty (IP) with or without regenerative procedures on treatment outcomes of peri-implantitis. MATERIALS AND METHODS: Electronic and manual literature searches were conducted for clinical trials published up to October 2020 that evaluated clinical outcomes (at least 6-month follow-up) after peri-implantitis treatment involving IP. The implant survival rate and clinical parameters (eg, probing depth [PD], bleeding on probing [BOP], marginal bone loss [MBL], clinical attachment level [CAL], and mucosal recession [REC]) at baseline and follow-ups were extracted from original articles for qualitative analyses. Risk ratio and weighted mean difference with 95% CI were calculated using a random-effects model. RESULTS: Out of 322 studies, 17 (9 randomized controlled trials, 4 controlled clinical trials, and 4 case series) were included in the present study. The regeneration group presented a 97% (95% CI: 0.95 to 1.00) implant survival rate, and the nonregeneration group showed a 94% (95% CI: 0.90 to 0.98) survival rate. Both groups revealed similar outcomes in PD and BOP reductions and soft tissue REC. However, the regeneration group had more favorable results in MBL. CONCLUSION: Data from this study suggested that applying implantoplasty during a regeneration or nonregeneration surgical approach resulted in a high implant survival rate and peri-implantitis resolution. Although no differences were found in the majority of clinical parameters in both groups, the regenerative approach resulted in more radiographic bone fill than the nonregenerative treatment.

Evolución de la osteosíntesis de los huesos largos y fijación por enclavado intramedular flexible / Evolution of Long Bone Osteosynthesis and Flexible Intramedullary Nail Fixation

Introducción: Se presenta la evolución histórica y científica de la osteosíntesis de huesos largos realizada con dos tipos de implantes intramedulares: Pines o varillas flexibles y clavos rígidos. Objetivo: Publicar un artículo científico que sirva de soporte teórico y práctico al personal en formación y, como punto de referencia y consulta a los ortopédicos y traumatólogos. Métodos: Se realiza una revisión bibliográfica retrospectiva de artículos sobre fracturas de los miembros publicadas en revistas de traumatología nacionales y extranjeras indexadas en las bases de datos MEDLINE y certificadas por el organismo de Ciencia Tecnología y Medio Ambiente, así como libros de relevancia sobre este tema y experiencias de los autores. Dadas las diferencias entre los dos tipos de implantes se estudiaron por separado la osteosíntesis con pines flexibles (Rush) y la realizada con clavos rígidos (Küntscher). Se seleccionaron las siguientes variables para el estudio: reducción, vía de acceso, penetración del implante, estabilidad, bloqueo, metal usado y consolidación. La fecha de incorporación de las innovaciones tecnológicas a la práctica quirúrgica fue enmarcada en tres momentos generacionales en el período de tiempo comprendido desde 1939 hasta la actualidad. Conclusiones: Esta revisión permitió identificar dos tipos de implantes intramedulares: los pines flexibles y los clavos rígidos. El estudio de sus características permitió organizarlos en generaciones para poder ubicar en el tiempo su contribución a los conocimientos que permiten devolver al paciente su vida activa(AU)

Introduction: This article discuses the historical and scientific evolution of long bone osteosynthesis performed with two types of intramedullary implants, flexible pins or rods and rigid nails. Objective: To publish a scientific article that serves as theoretical and practical support for staff in training and, as a point of reference and consultation for orthopedists and traumatologists. Methods: A retrospective bibliographic review of articles is carried out on limb fractures published in local and foreign trauma journals indexed in the MEDLINE databases and certified by CITMA, as well as relevant books on this topic and experiences of the authors. Given the differences between the two types of implants, we separately studied the osteosynthesis with flexible pins (Rush) from that performed with rigid pins (Küntscher). The variables selected for the study were reduction, access route, implant penetration, stability, locking, metal used, and consolidation. The inclusion of technological innovations to surgical practice was framed in three generational moments from 1939 to the present. Conclusions: Thow types of intramedullary implants were identifies from this revision: flexible pins and rigid nails. The study of their characteristics allowed to organize them into generations in order to locate their contribution to the knowledge allowing the patient to return to an active life over time(AU)

Prediction of temperature elevation in rotary ultrasonic bone drilling using machine learning models: An in-vitro experimental study.

Bone drilling is frequently used during orthopaedic surgeries to treat the fractured part of the bone. A major concern for surgeons is the increase in temperature during real-time orthopaedic bone drilling. The temperature elevation at the bone-tool interface may cause permanent death of regenerative soft tissues and cause thermal osteonecrosis. A robust predictive machine-learning model is suggested in this in-vitro research for monitoring temperature rise during surgery. The objective of the present work is to introduce different machine learning algorithms for predicting temperature elevations in rotary ultrasonic bone drilling. Different machine-learning models were compared with the standard response surface methodology. The performance and accuracy of different predictive models were compared at different error metrics. It was witnessed that support vector machines performed the best for predicting the change in temperature in comparison to other predictive models. Moreover, the error metrics for statistical response surface methodology analysis were comparatively higher than the machine learning algorithms. By using machine learning models, it is possible to predict temperature rise during bone drilling.

Experimental study of bone drilling by Kirschner wire.

Mechanical and thermal damage to the bone tissue during drilling process is inevitable and directly affects the postoperative recovery. According to clinical practices and present academic investigations, this study tries to reduce bone damage by experimental investigation of bone drilling by Kirschner wire considering the drilling force and temperature factors. Finite element method has been applied to modelling of the drilling process. Then, grouped experiments have been carried out using bovine femoral bone and analyzed based on the orthogonal experimental method. The influence of key parameters such as Kirschner wire bevel angle, feed speed and rotational speed on the microscopic bone chip size, drilling force, drilling temperature and hole inlet burr was analyzed to conduct comprehensive analysis and optimizations. It is certain that the chips size is closely related to drilling force and drilling temperature. The low drilling temperature does not mean that the damage area is small. The drilling process should be completed quickly at high feed rates. The lower rotational speed, Kirschner wire bevel angle, and higher feed rate help reduce the thermal damage area of the bone drill, effectively reduce the drilling force and hole entrance burrs.