Stability Analysis of Plate-Screw Fixation for Femoral Midshaft Fractures.

An understanding of the biomechanical characteristics and configuration of flexible and locked plating in order to provide balance stability and flexibility of implant fixation will help to construct and promote fast bone healing. The relationship between applied loading and implantation configuration for best bone healing is still under debate. This study aims to investigate the relationship between implant strength, working length, and interfragmentary strain (εIFM) on implant stability for femoral midshaft transverse fractures. The transverse fracture was fixed with a fragment locking compression plate (LCP) system. Finite element analysis was performed and subsequently characterised based on compression loading (600 N up to 900 N) and screw designs (conventional and locking) with different penetration depths (unicortical and bicortical). Strain theory was used to evaluate the stability of the model. The correlation of screw configuration with screw type shows a unicortical depth for both types (p < 0.01) for 700 N and 800 N loads and (p < 0.05) for configurations 134 and 124. Interfragmentary strain affected only the 600 N load (p < 0.01) for the bicortical conventional type (group BC), and the screw configurations that were influenced were 1234 and 123 (p < 0.05). The low steepness of the slope indicates the least εIFM for the corresponding biomechanical characteristic in good-quality stability. A strain value of ≤2% promotes callus formation and is classified as absolute stability, which is the minimum required value for the induction of callus and the maximum value that allows bony bridging. The outcomes have provided the correlation of screw configuration in femoral midshaft transverse fracture implantation which is important to promote essential primary stability.

An In-Vitro Analysis of Root Fracture Strength Using Single File Systems.

Aim Root canal obturation during endodontic therapy supports the root canal space and helps the extra tooth structure resist fracture. Some believe endodontic-treated teeth are more likely to break than natural teeth. The most common causes of tooth decay are endodontic treatment's extensive tooth structure loss and coronal and radicular dentin drying. Materials and methods Two hundred removed human permanent mandibular first molars were allowed to be stored in isotonic saline solution for a maximum of 72 hours. The collection, storing, sterilizing, and handling of the samples were done per the Occupational Safety and Health Administration (OSHA) and Centers for Disease Control and Prevention (CDC) guidelines. Out of a total of 200 newly removed mandibular first molars, 120 teeth were finally gathered, sterilized, and kept in 1% thymol in normal saline at 30 degrees Celsius. The access cavity was prepared, and the pulp chamber was cleaned and debrided using an ultrasonic scaler tip while being irrigated with regular saline. A digital radiograph was taken after a 6# K file was placed to the working length in the mesiobuccal canal. Based on their weights, the samples were dispersed equally across the six groups (n=20). They looked inside them to ensure that the root morphology was normal and that the canal was open and free of any abnormalities, damage, or fillings. They looked at the curvature of the mesial root and chose samples with a curvature of 20-35 degrees. The mesial roots were dissected, labeled, and put in a different location. Results Overall, the experimental group's incidence of buccolingual fractures was 55%, making it the most prevalent fracture type. The mesiodistal type of fracture had a 35% incidence rate, which was the second most prevalent. We found that comminuted and transverse fractures occurred in only 15% and 5% of patients, respectively, of all fractures. Both the test and the control groups had a disproportionately high number of buccolingual fractures. When comparing the root fracture loads of the two experimental groups, there was no significant difference (p>0.05) Conclusion Within this study's restrictions and standardization techniques, it can be concluded that the single file system-prepared roots' resistance to fracture was comparable to that of the control group. It is recommended to conduct additional research on these single file systems using different metrics and to assess them in a clinical setting.

Pelvic incidence-guided reduction in transverse parts of U-shaped sacral fractures: Technical recommendations.

OBJECTIVE: The purpose of this study is to present a surgical technique that simultaneously reduces and fixates the transverse parts of U-shaped sacral fractures. METHODS: The sacral fracture was exposed through a posterior median approach. In a flexion injury, the rotation of the lower sacral segment is reduced by distraction along a pre-curved rod. Then, lordotic restoration is performed with a Weber clamp placed at the lower sacral segment through dragging. In an extension injury, longitudinal distraction is performed along the spinopelvic rod to reduce the vertical displacement. Next, the transverse displacement is reduced by a dissector placed between the upper and lower sacral segments through levering. The sagittal reduction on the lateral pelvic view was judged by PI. A regression analysis of Oswestry disability index (ODI) with Z-scores of PI, lumbar lordosis (LL), sacral slope (SS), and pelvic tilt (PT) was performed. RESULTS: At the 1-year follow-up, the average PI, LL, SS, and PT values were 51.6 (range: 43.1-76.0), 44.8 (34.6 - 60.1), 35.4 (18.1 - 48.0), and 16.7 (2.2-35.4) degrees, respectively. All patients were able to maintain an upright stance. The average ODI was 27.6% (2-72%). Surprisingly, the regression analysis demonstrated a significant linear relationship between ODI and LL (R2 = 0.367, p = .048) but not between ODI and PI (R2 = 0.227, p = .138). CONCLUSIONS: Using PI as guidance, the surgical procedures were helpful to reduce the PI of transverse sacral fractures into the normal range. However, the relationship between PI and the prognosis remains to be evaluated by future researches.

Three-dimensional mapping study of pure transverse acetabular fractures.

BACKGROUND: To describe and analyze the morphological characteristics, location and frequency of pure transverse acetabular fracture lines through fracture mapping and quantitative measurements. METHODS: Transverse fractures were retrospectively reviewed and analyzed. All computed tomography (CT) data were used for reconstruction and manual reduction. The reductive fracture fragments were graphically overlaid onto a three-dimensional (3D) right hemipelvis template. Then, the fracture lines were accurately depicted onto the surface of the 3D template. The fracture lines were overlapped onto the model to create the 3D fracture map and heatmap. All cases were subdivided into infratectal (62-B1.1), juxtatectal (62-B1.2), and transtectal (62-B1.3) types based on the AO Foundation/Orthopedic Trauma Association (AO/OTA) classification. Some anatomic parameters of the transverse fractures were also analyzed in these 3 groups. RESULTS: Our study included forty-nine transverse fractures from 32 male and 17 female patients (mean age, 42 years; range 21-74 years) and included 19 type 62-B1.1, 17 type 62-B1.2, and 13 type 62-B1.3 fractures. The average anterior rim fracture angle was 70.0° (± 11.6°), and the posterior rim fracture angle was 92.4° (± 28.5°). The anterior rim fracture angles in 40 cases (40/49, 81.6%) fell within a wide range between 63° and 80°. On the heatmap, the hot zones were located on the highest position of the cotyloid fossa and the narrowed region, and the cold zone was on the inferior third of the articular surface. For type 62-B1.3 fractures, the hot zone was located on the posterior of the acetabular dome. There were no significant differences in anterior rim fracture angle and anterior height among the three patterns (P = 0.071, P = 0.072). Post hoc tests of the posterior rim fracture angle and the posterior height revealed significant differences among fracture subtypes (P < 0.01). The posterior intra-articular fracture line was significantly longer than the anterior intra-articular fracture line in type 62-B1.1 and type 62-B1.2 fractures (P < 0.01). CONCLUSION: The fracture lines of transverse fractures through the anterior rim were concentrated on the narrowed zone, and the posterior fracture lines were diffusely distributed. The intra-articular fracture line distribution was focused on the superior and middle thirds of the joint surface. The recurrent fracture lines involving the weight-bearing dome mainly converged on the posterior region of the roof.

Mechanical Properties of Novel Interlocking Intramedullary Nail for Fixing Transverse Olecranon Fractures / 医用生物力学

Objective To study the effect of interlocking intramedullary nail on fixing transverse olecranon fracture. Methods Nine pairs of fresh ulna specimens were collected and the transverse fracture model of olecranon was established. Kirschner wire tension band and interlocking intramedullary nail were used to repair the fracture. Cyclic dynamic tension loads with amplitude of 25 N, mean value of 45 N and frequency of 05 Hz were applied to the triceps tendon under simulated elbow flexion conditions of 30°, 45° and 60°, respectively. The fracture displacements of specimens within 300 cycles were recorded in three groups. ResultsAt 30° flexion angle, the fracture displacement of interlocking intramedullary nail group and Kirschner wire tension band group was (1.831±0.333) mm and (3.723±2.390) mm, respectively. At 45° flexion angle, the fracture displacement of interlocking intramedullary nail group and Kirschner wire tension band group was (1.167±0.374) mm and (2.455±0.609) mm, respectively. At 60° flexion angle, the fracture displacement of interlocking intramedullary nail group and Kirschner wire tension band group was (1.407±0.342) mm and (3.112±1.025) mm, respectively. The fracture displacement of interlocking intramedullary nail was smaller. Conclusions The mechanical properties of interlocking intramedullary nail are better than those of Kirschner wire tension band, and the interlocking intramedullary nail is more stable and firmer for fixing transverse olecranon fracture. Moreover, the interlocking intramedullary nail is installed with the operating tool, thus the operation is more accurate and faster, and the operation efficiency is greatly improved.

Stress Distribution and Stability Evaluation of Difference Number of Screws for Treating Tibia Transverse Fracture: Analysis on Patient-Specific Data

@#Introduction: Screws placement may influence the stress distribution and stability of the plate and bone. Implant failures are normally happened in clinical practise when inappropriate number of screws is implemented. Therefore, intensive investigations are needed to provide additional quantitative data on the use of different number of screws. Therefore, this study was conducted to investigate the biomechanical performance of different number of screws configurations on Locking compression plate (LCP) assembly when treating transverse fractures of the tibia bone. Methods: Finite element method was used to simulate tibia bone fracture treated with LCP in standing phase simulation. To accomplish this, a three-dimensional tibia model was reconstructed using CT dataset images. 11 holes of LCP and 36mm of locking screws were developed using SolidWorks software. From this study, there are three models in total have been developed with different number of screws and screw placements. A diaphysis transverse tibia fracture of 4 mm was constructed. Results: In terms of stress distribution, all configurations provide sufficient stress and do not exceeding the yield strength of that material. Conclusion: In conclusion, eight numbers of screws were the optimum configurations in order to provide ideal stability to the bone with displacement of 0.37 mm and 0.91 mm at plate and bone, respectively.

Biomechanical Analysis of the Kirschner-Wire Depth of the Modified Tension Band Wiring Technique in Transverse Patellar Fractures: An Experimental Study Using the Finite-Element Method.

BACKGROUD: Modified tension band wiring is one of the most preferred surgical methods for transverse patellar fractures. However, the optimal depth or sagittal position of a Kirschner wire (K-wire) in modified tension band wiring has yet to be determined. The purpose of this study was to evaluate whether the depth of a K-wire affects the biomechanical characteristics of modified tension band wiring using the finite-element method. METHODS: A patella model was designed with a cuboid shape (length, 34.3 mm; width, 44.8 mm; and thickness, 22.4 mm) and divided into the cortical and cancellous bone parts. A transverse fracture line was formed on the midline of the cuboid shape model. The cuboidal model was applied to modified tension band wiring. The depth or sagittal position of the K-wire was divided into superficial, center, and deep. With the Abaqus v2017 program (Dassault System Inc.), the distal part of the model was fixed, and a tensile load of 850 N was applied to the proximal part of the model at an angle of 45°. The maximum pressures of the cortical and cancellous bones at the fracture plane were measured. The largest von Mises values of the K-wire and stainless steel wire were also measured. The fracture gap on the distracted or anterior side was measured. RESULTS: In deep K-wire placement, the highest peak von Mises values of the cortical and cancellous bones were observed. The K-wire and stainless steel wire showed the highest von Mises values in deep K-wire placement. The fracture gap was also largest in deep K-wire placement. CONCLUSIONS: The depth of the K-wire affects the biomechanical characteristics of modified tension band wiring. Deep placement of the K-wire will be more favorable for bone union than the empirically known 5-mm anterior or center placement of the K-wire.

Biomechanical comparison of fixation techniques for transverse acetabular fractures - Single-leg stance vs. sit-to-stand loading.

OBJECTIVES: To biomechanically compare five different fixation techniques for transverse acetabular fractures using both the single-leg stance (SLS) and the sit-to-stand (STS) loading protocols and to directly compare fracture gap motion (FGM) and relative interfragmentary rotation (RIFR). METHODS: Transtectal transverse acetabular fractures were created on fourth-generation composite hemipelves in a reproducible manner. Five different fixation techniques were biomechanically assessed using both an SLS and STS loading protocol: anterior plate (AP) only, posterior plate (PP) only, anterior plate plus posterior column screw (AP+PCS), posterior plate plus anterior column screw (PP+ACS) and anterior plus posterior plate (AP+PP). After preconditioning, the specimens were loaded from 50 to 750 N with a ramp of 100 N/s. FGM and RIFR under loads of 750 N were measured using an optical 3D measurement system. RESULTS: In the three groups of fixation techniques addressing both columns, STS loading resulted in higher mean FGM and in RIFR than SLS loading. No construct failure was observed. In the single plate groups (AP only and PP only), STS loading resulted in failure of all specimens before reaching loads of 750 N, while no failure occurred after SLS loading. No significant differences in FGM and RIFR were found between the double plate (AP+PP) and the single plate plus column screw (AP+PCS and PP+ACS) techniques. CONCLUSION: SLS loading appeared to overestimate the strength of acetabular fracture fixation constructs and STS loading may be more appropriate to provide clinically relevant biomechanical data. Internal fixation of a single column might not provide adequate stability for transverse fractures, while strength of single plate plus column screw fixation and double plate fixation was comparable.

Comparison of a minimally invasive surgical technique with open surgery for transverse patella fractures.

The current study aimed to compare a minimally invasive surgical technique with open surgery for the treatment of transverse patella fractures. A total of 38 patients with displaced transverse fractures of the patella were included in the current prospective study. A total 21 of them were treated with a minimally invasive surgical (MIS) technique and the other 17 patients had open surgery (OS) when using the Cable Pin System. Postoperative comparisons were based on radiographs, the visual analog scale (VAS) of pain, their ranges of motion and the Bostman grading scale. Compared with the OS group, the VAS score for pain was significantly lower and the angle of active flexion was better in the MIS group at 4 and 8 weeks. The angle of active extension at 4 weeks and the Bostman score at 8 weeks after surgery were better in the MIS group, although the differences became non-significant at 8 weeks and 12 months. In conclusion, the MIS technique for transverse patella fractures provided better clinical results and the knees functioned with less pain when compared with the OS group in the early period following surgery. MIS could be an adequate alternative in the treatment of transverse patella fractures.

Genetic variation in mice affects closed femoral fracture pattern outcomes.

The purpose of this study was to determine whether differences in structural and material properties of bone between different mouse strains influence the fracture patterns produced under experimental fracture conditions. Femurs of C57BL/6 (B6), C3H/HeJ (C3H), and DBA/2 (DBA) strains were evaluated using micro-computed tomography (µCT), measurements derived from radiographic images and mechanical testing to determine differences in the geometry and mechanical properties. A fracture device was used to create femoral fractures on freshly sacrificed animals using a range of kinetic energies (∼20-80mJ) which were classified as transverse, oblique, or comminuted. B6 femurs had the lowest bone volume/total volume (BV/TV) and bone mineral density (BMD), thinnest cortex, and had the most variable fracture patterns, with 77.5% transverse, 15% oblique, and 7.5% comminuted fractures. In contrast, C3H had the highest BV/TV, BMD, and thickest cortices, resulting in 97.5% transverse, 2.5% oblique, and 0% comminuted fractures. DBA had an intermediate BV/TV and thickness of cortices, with BMD similar to C3H, resulting in 92.9% transverse, 7.1% oblique, and 0% comminuted fractures. A binomial logistic regression confirmed that bone morphometry was the single strongest predictor of the resulting fracture pattern. This study demonstrated that the reproducibility of closed transverse femoral fractures was most influenced by the structural and material properties of the bone characteristics in each strain, rather than the kinetic energy or body weight of the mice. This was evidenced through geometric analysis of X-ray and µCT data, and further supported by the bone mineral density measurements from each strain, derived from µCT. Furthermore, this study also demonstrated that the use of lower kinetic energies was more than sufficient to reproducibly create transverse fractures, and to avoid severe tissue trauma. The creation of reproducible fracture patterns is important as this often dictates the outcomes of fracture healing, and those studies that do not control this potential variability could lead to a false interpretation of the results.

[Effectiveness of high strength suture fixation in treatment of patellar transverse fracture].

Objective: To explore the effectiveness of high strength suture fixation in treatment of patellar transverse fracture. Methods: Between June 2014 and June 2016, 38 patients with the patellar transverse fracture were treated with high strength suture internal fixation. There were 24 males and 14 females with the age of 26 to 64 years (mean, 45 years). There were 6 cases of accident injury and 32 cases of crashing injury. The time interval between injury and surgery was 2-8 days (mean, 5 days). The preoperative visual analogue scale (VAS) score, Lysholm score, and range of motion (ROM) of patients were 84.3±8.4, 44.5±7.2, and (62±12)°, respectively. Results: All patients' incisions healed by first intention after operation. There was no neurovascular injury, deep venous thrombosis of lower limbs, or local foreign matter irritation reaction. The X-ray films showed that the reduction of patella and the location of internal fixator were good at 2 days after operation. All the 38 patients were followed up 12-18 months (mean, 16 months). All fractures healed and the healing time was 2-4 months (mean, 3 months). At last follow-up, according to the Böstman criteria, 36 patients were rated as excellent and 2 as good, with an excellent and good rate of 100%. The VAS score, Lysholm score, and ROM of patients were 10.2±6.6, 93.1±6.4, and (124±14)°, respectively, showing significant differences when compared with preoperative ones ( t=42.759, P=0.000; t=31.099, P=0.000; t=20.727, P=0.000). Conclusion: Application of high strength suture fixation in the treatment of patellar transverse fracture has advantages of simple to operate, effective fixation, and less complication. It can avoid reoperation of removing the internal fixators. The satisfied ROM and function of the knee joint can be obtained after operation.

Effectiveness of high strength suture fixation in treatment of patellar transverse fracture / 中国修复重建外科杂志

Objective: To explore the effectiveness of high strength suture fixation in treatment of patellar transverse fracture. Methods: Between June 2014 and June 2016, 38 patients with the patellar transverse fracture were treated with high strength suture internal fixation. There were 24 males and 14 females with the age of 26 to 64 years (mean, 45 years). There were 6 cases of accident injury and 32 cases of crashing injury. The time interval between injury and surgery was 2-8 days (mean, 5 days). The preoperative visual analogue scale (VAS) score, Lysholm score, and range of motion (ROM) of patients were 84.3±8.4, 44.5±7.2, and (62±12)°, respectively. Results: All patients' incisions healed by first intention after operation. There was no neurovascular injury, deep venous thrombosis of lower limbs, or local foreign matter irritation reaction. The X-ray films showed that the reduction of patella and the location of internal fixator were good at 2 days after operation. All the 38 patients were followed up 12-18 months (mean, 16 months). All fractures healed and the healing time was 2-4 months (mean, 3 months). At last follow-up, according to the Böstman criteria, 36 patients were rated as excellent and 2 as good, with an excellent and good rate of 100%. The VAS score, Lysholm score, and ROM of patients were 10.2±6.6, 93.1±6.4, and (124±14)°, respectively, showing significant differences when compared with preoperative ones ( t=42.759, P=0.000; t=31.099, P=0.000; t=20.727, P=0.000). Conclusion: Application of high strength suture fixation in the treatment of patellar transverse fracture has advantages of simple to operate, effective fixation, and less complication. It can avoid reoperation of removing the internal fixators. The satisfied ROM and function of the knee joint can be obtained after operation.

The Nonoperative Management of Hand Fractures in United Kingdom.

Hand fractures (excluding small avulsion fractures and scaphoid fractures) almost always unite with bone. The role of the hand surgeon is not to achieve bone union but to achieve stability in an adequate position, often with some displacement, and maintenance of good soft tissue gliding. This article establishes that many fractures treated operatively do no better and often could not realistically do better than with good nonoperative treatment. Yet many are treated surgically to satisfy surgical egos, the desire to produce excellent radiographs, or just the mistaken belief that current surgical techniques can improve on nonoperative treatment.

Internal Fixation of Transverse Patella Fractures Using Cannulated Cancellous Screws with Anterior Tension Band Wiring.

Aims: To evaluate the effectiveness and safety of anterior tension band wiring technique using two cannulated cancellous screws in patients with transverse (AO34-C1) or transverse with mildly comminuted (AO34-C2) patellar fractures. Materials and Methods: This is a prospective study of 25 patients with transverse fracture or transverse fracture with mildly comminuted patella fractures. All the patients were treated with open reduction and internal fixation using two parallel cannulated screws and 18G stainless steel wire as per the tension band principle. Results: There were eighteen males (72%) and seven females (28%). The age group ranged from 24 to 58 years, with mean age of 38 years. The most common mode of injury was fall (72%) followed by road traffic accident (20%) and violent quadriceps contraction (8%). Transverse fracture was present in 60% and transverse fracture with mild comminution in 40% of patients. Mean time to achieve union was 10.7 weeks (range 8-12 weeks). Mean ROM at three months was 113.8 degree (90-130) and at final follow up this improved to 125.4 degrees (range 100-140). There was one case of knee stiffness and no case of implant failure was observed. Patients were evaluated using Bostman scoring, the mean score at three months being 26.04 which improved to 27.36 at the end of final follow up at one year. Conclusion: Cannulated cancellous screws with anterior tension band wiring is a safe, reliable and reproducible method in management of transverse patellar fractures, with less chances of implant failure and soft tissue irritation.

Arthroscopy Assisted 2 Cannulated Screw Fixation for Transverse Glenoid Fracture: A Case Report

Arthroscopy is recognized as an important adjunct in treatment of intra-articular fractures. The author reports on successful treatment of a displaced transverse glenoid cavity fracture, reduced and fixed with arthroscopic assist, using two cannulated screws perpendicular to the fracture surface, in a patient with frail chest. One screw passed through the Neviaser portal, and the other screw passed through the base of the coracoid process. Arthroscopy assisted reduction and 2 cannulated screw fixation through the Neviaser portal and coracoid base appears to be a good method for treatment of transverse glenoid fractures.

Arthroscopy Assisted 2 Cannulated Screw Fixation for Transverse Glenoid Fracture: A Case Report

Arthroscopy is recognized as an important adjunct in treatment of intra-articular fractures. The author reports on successful treatment of a displaced transverse glenoid cavity fracture, reduced and fixed with arthroscopic assist, using two cannulated screws perpendicular to the fracture surface, in a patient with frail chest. One screw passed through the Neviaser portal, and the other screw passed through the base of the coracoid process. Arthroscopy assisted reduction and 2 cannulated screw fixation through the Neviaser portal and coracoid base appears to be a good method for treatment of transverse glenoid fractures.

Laminoplasty for Treatment of Transverse Sacral Fracture: A Case Report

The transverse sacral fracture is rare; however, if it accompanies neurological injury or instability, difficult surgical treatment may be necessary. We performed surgical decompression and laminoplasty in a patient with neurological deficits and anterior displacement of S2 on S1. The patient showed a successful clinical outcome by neurological improvement.

Prospective study of 'otological injury secondary to head trauma'.

The aim of study was to evaluate etiological factors, types of skull fracture and associated hearing loss in 50 cases of head injury. This was prospective study involving 50 cases of head injury. Each patient will be subjected to detailed history, otological and neuro otological examination, radiological study followed by audiological assessment by pure tone audiometry. Road traffic injuries were the most frequent cause of injuries in our patients comprising 64% of the total, personal accidents/domestic falls, assaults and agriculture and related injuries were responsible for 8% of the total injuries each. Other causes of the injuries were sports injuries (6%), industrial accidents (4%) and fire arm injuries (2%). Out of the 9 patients having temporal bone fracture 7 cases (78%) had longitudinal fracture and 2 cases (22%) had transverse fracture. Out of the 21 patients having hearing loss, 5 patients (23.8%) had conductive hearing loss, 9 patients (42.86%) had mixed hearing loss and 7 patients (33.34%) had sensorineural hearing loss. Facial nerve palsy was present in 2 patients (28%) among longitudinal fracture cases and 1 patient (50%) among transverse fracture cases. Motor Vehicular accident (MVA) are still the commonest cause of injuries compared to the other mode of injury. Patients with longitudinal fracture showed conductive and mixed loss and patients with transverse fracture showed sensorineural hearing loss. Incidence of facial nerve paralysis was more with transverse fracture cases than with longitudinal fracture cases.

Treatment of Transverse Patellar Fracture with Cannulated Screws

PURPOSE: To assess the indication and effect of screw fixation in the transverse patellar fractures. MATERIALS AND METHODS: We analysed the results of 14 transverse patellar fractures fixed with screws from January 1991 to May 2005. Mean follow-up period was 47 months (range, 12~143 months). We analysed the radiologic union, operation time, ROM and postoperative Lysholm score. RESULTS: All fractures healed uneventfully. The mean displacement was decreased from 2.2 mm preoperatively to 0.3 mm postoperatively (p=0.001, Wilcoxon signed rank test). The mean operation time was 34 minutes (range, 20 to 60 minutes). Normal range of motion was achieved in 13 knees (92.9%). Average Lysholm score was 95.9 at final follow-up. CONCLUSION: Screw fixation seemed to be useful for treatment of transverse patellar fracture even in comminuted fractures with large fragments. The advantage of this technique was the preservation of extensor mechanism, simplicity, short operation time and good cosmesis.