The small screw-apex distance is potentially associated with femoral head osteonecrosis in adults with femoral neck fractures treated by closed reduction and percutaneous 3 parallel cannulated screws.

OBJECTIVE: Femoral neck fractures (FNFs) are among the most common fractures in elderly individuals. Surgery is the main treatment for FNFs, and osteonecrosis of the femoral head (ONFH) is one of the unacceptable complications. This study aimed to assess both the clinical and radiological outcomes in patients with FNFs treated with three parallel cannulated screws and to identify relationship between screws position and ONFH. PATIENTS AND METHODS: A total of 100 patients who were treated with closed reduction and fixed with 3 parallel cannulated screws met the inclusion criteria between January 2014 and December 2020 at authors' institution. The follow-up duration, age, sex, affected side, and injury-to-surgery interval were collected; the neck-shaft angle of both hips, screw-apex distance (SAD) and the tip-apex distance (TAD)were measured; and the Garden classification, quality of reduction and presence of ONFH were evaluated. RESULTS: The sample consisted of 37 males and 63 females, with 60 left and 40 right hips affected. The mean age of patients was 54.93 ± 12.24 years, and the mean follow-up was 56.3 ± 13.38 months. The overall incidence of ONFH was 13%. No significant difference was observed in the incidence of ONFH by affected side, age, fracture displacement, injury-to-surgery interval, neck-shaft angle deviation, or reduction quality. The SAD was significantly shorter in ONFH patients than in normal patients for all three screws (p = 0.02, 0.02, and 0.01, respectively). CONCLUSIONS: The short SAD of all screws is associated with femoral head necrosis of FNFs treated with 3 cannulated screws. The short SAD indicated that screws malpositioning in the weight-bearing area of the femoral head, potentially harming the blood supply and compromising the anchorage of the primary compressive trabeculae in this region.

CURRENT CONCEPTS IN THE MANAGEMENT OF BOXER'S FRACTURE.

Fractures of the metacarpal particularly the 5th metacarpal is quite common among all hand fractures and has a high incidence in male adult population. Proper management of these fractures plays a key role in rehabilitation and early return to work thus reducing the economic burden. Treatment of these injuries depends on the type of injury: whether it is a closed/open fracture, degree of angulation at the fracture site and also mal-rotation and shortening of the finger. Non-operative management is suitable for fractures which are closed, non-displaced and without angulation or rotation. Open fractures, fractures with angulation and/or mal-rotation and fractures with neuro-vascular injury are more suitable for operative management. The acceptable angulation for conservative management for most studies is 70 degrees. Buddy strapping with a Futura splint provides good functional results. In fractures requiring operative intervention, K-wire fixation is a minimally invasive method of fixation, which in most cases has good functional results. Plate and screw fixation, however, is preferred for cases with significant comminution or multiple metacarpal fractures.

THE ROLE OF DISTAL LOCKING IN INTRAMEDULLARY NAILS FOR HIP FRACTURE FIXATION: A REVIEW OF CURRENT LITERATURE.

Traditionally, it was believed that both proximal and distal locking are essential for achieving stability during intra-medullary fixation for extra-capsular hip fractures. However, recent literature has presented varying perspectives on the necessity of distal locking. Distal locking plays a significant role in managing hip fractures with uncertainties regarding longitudinal and rotational stability. This includes cases of comminuted intertrochanteric fractures with subtrochanteric extension, reverse oblique and high oblique fractures, broad medullary canals, comminution of the lateral wall, diaphyseal fractures, and large posteromedial fragments extending below the level of the lesser trochanter. In stable pertrochanteric fractures, with the lag screw passing through the lateral cortex of the distal fragment, may not require a distal locking screw. Distal locking has been associated with potential complications, including irritation of the fascia lata, prolonged operation time, increased radiation exposure, greater blood loss, implant loosening, secondary femoral stress fractures, and damage to the femoral artery. Thus, although distal locking is of doubtful significance in stable pertrochanteric fractures it is essential in unstable fracture patterns.

A novel model of locking plate and locking spongious screw: a biomechanical in vitro comparison study with classical locking plate.

BACKGROUND: Locking plates are commonly used for the fixation of comminuted, periprosthetic and osteoporotic bone fractures. These plates are secured to the bone with screws, creating a stable connection with fixed angle between the plate and the screws. In this biomechanical in vitro study, our aim is to evaluate and compare the novel locking plate-locking spongious screw model with FDA approved classical locking plate. METHODS: Sawbone PCF-15 osteoporotic bone model was utilized to simulate osteoporotic bone conditions. Two screws were used to attach both the classical locking plate and the novel locking plate-locking spongious screw model to these bone models. The attachment strength of the screws to the bone blocks was measured by pull-out tests. RESULTS: Novel locking plate-locking spongious screw model exhibited an 84.38% stronger attachment to the osteoporotic bone model compared to the current locking plate model. CONCLUSIONS: In conclusion, one of the important problems in the locking plates which is the high Pull-out risk of the locking spongious screws can been resolved with our proposed new model and has a chance of having a better purchase especially in osteoporotic bones.

Critical loss of primary implant stability in osteosynthesis locking screws under cyclic overloading.

Primary implant stability, which refers to the stability of the implant during the initial healing period is a crucial factor in determining the long-term success of the implant and lays the foundation for secondary implant stability achieved through osseointegration. Factors affecting primary stability include implant design, surgical technique, and patient-specific factors like bone quality and morphology. In vivo, the cyclic nature of anatomical loading puts osteosynthesis locking screws under dynamic loads, which can lead to the formation of micro cracks and defects that slowly degrade the mechanical connection between the bone and screw, thus compromising the initial stability and secondary stability of the implant. Monotonic quasi-static loading used for testing the holding capacity of implanted screws is not well suited to capture this behavior since it cannot capture the progressive deterioration of peri­implant bone at small displacements. In order to address this issue, this study aims to determine a critical point of loss of primary implant stability in osteosynthesis locking screws under cyclic overloading by investigating the evolution of damage, dissipated energy, and permanent deformation. A custom-made test setup was used to test implanted 2.5 mm locking screws under cyclic overloading test. For each loading cycle, maximum forces and displacement were recorded as well as initial and final cycle displacements and used to calculate damage and energy dissipation evolution. The results of this study demonstrate that for axial, shear, and mixed loading significant damage and energy dissipation can be observed at approximately 20 % of the failure force. Additionally, at this load level, permanent deformations on the screw-bone interface were found to be in the range of 50 to 150 mm which promotes osseointegration and secondary implant stability. This research can assist surgeons in making informed preoperative decisions by providing a better understanding of the critical point of loss of primary implant stability, thus improving the long-term success of the implant and overall patient satisfaction.

Early Return of Motion in Patients With Intramedullary Screw Placement for Metacarpal and Phalangeal Fracture Fixation.

INTRODUCTION: Hand fractures are associated with significant morbidity. Current management standards often result in prolonged immobilization, stiffness, and delayed return to functional use. Intramedullary (IM) compression screws offer minimal soft tissue disruption and early postoperative active motion. In this study, we describe our outcomes after intraosseous fracture fixation using IM cannulated headless screws for a multitude of fracture patterns. METHODS: This study is a retrospective review of patients who underwent IM screw placement for fixation of metacarpal and phalangeal fractures by a single surgeon from 2017 to 2022. Data were collected to include patient demographics, fracture details, postoperative complications, and follow-up. Time to range of motion and return to unrestricted motion was recorded. RESULTS: There were 69 patients with 92 fractures (n = 54 metacarpal, n = 38 phalanx). The median patient age was 45 years (range, 18-89 years) with 75.4% males. Majority presented with a single fracture (n = 50, 72.5%), and 38 patients (55.1%) had open fractures. Small finger was the most affected digit (n = 35, 37.6%). The median time to allow range of motion from surgery was 8.7 days (interquartile range, 0-32) with 32 days (interquartile range, 10-62) for unrestricted use of the hand. Thirty-five patients (50.7%) were allowed controlled motion from the first postoperative day. One patient had loss of reduction requiring reintervention for hardware removal, and 1 patient had superficial skin infection managed with oral antibiotics. CONCLUSIONS: Our findings indicate that the IM screw provides reliable fixation for a wide variety of fracture patterns with a low complication rate and offers early return to functional use.

Craniovertebral Junction Surgical Approaches: State of Art.

Surgical approaches directed toward craniovertebral junction (CVJ) can be addressed to the ventral, dorsal, and lateral aspects through a variety of 360° surgical corridors Herein, we report features, advantages, and limits of the updated technical support in CVJ surgery in clinical setting and dissection laboratories enriched by our preliminary surgical results of the simultaneous application of O-arm intraoperative neuronavigation and imaging system along with the 3D-4K EX in TOA for the treatment of CVJ pathologies.In the past 4 years, eight patients harboring CVJ compressive pathologies underwent one-step combined anterior neurosurgical decompression and posterior instrumentation and fusion technique with the aid of exoscope and O-arm. In our equipped Cranio-Vertebral Junction Laboratory, we use fresh cadavers (and injected "head and neck" specimens) whose policy, protocols, and logistics have already been elucidated in previous works. Five fresh-frozen adult specimens were dissected adopting an FLA. In these specimens, a TOA was also performed, as well as a neuronavigation-assisted comparison between transoral and transnasal explorable distances.A complete decompression along with stable instrumentation and fusion of the CVJ was accomplished in all the cases at the maximum follow-up (mean: 25.3 months). In two cases, the O-arm navigation allowed the identification of residual compression that was not clearly visible using the microscope alone. In four cases, it was not possible to navigate C1 lateral masses and C2 isthmi due to the angled projection unfitting with the neuronavigation optical system, so misleading the surgeon and strongly suggesting changing surgical strategy intraoperatively. In another case (case 4), it was possible to navigate and perform both C1 lateral masses and C2 isthmi screwing, but the screw placement was suboptimal at the immediate postoperative radiological assessment. In this case, the hardware displacement occurred 2 months later requiring reoperation.

Forces required to dynamize sliding screws in gamma nail and selfdynamizable internal fixator.

BACKGROUND: Single limb support phase of the gait-cycle in patients who are treated for a pertrochanteric fracture is characterized by transversal loads acting on the lag screw, tending to block its dynamization. If the simultaneous axial force overcomes transversal loads of the sliding screw, the dynamization can still occur. METHODS: Biomechanical investigation was performed for three types of dynamic implants: Gamma Nail, and two types of Selfdynamizable Internal Fixators (SIF) - SIF-7 (containing two 7 mm non-cannulated sliding screws), and SIF-10 (containing one 10 mm cannulated sliding screw). Contact surface between the stem and the sliding screws is larger in SIF implants than in Gamma Nail, as the stem of Gamma Nail is hollow. A special testing device was designed for this study to provide simultaneous application of a controlled sliding screws bending moment and a controlled transversal load on sliding screws (Qt) without using of weights. Using each of the implants, axial forces required to initiate sliding screws dynamization (Qa) were applied and measured using a tensile testing machine, for several values of sliding screws bending moment. Standard least-squares method was used to present the results through the linear regression model. RESULTS: Positive correlation between Qt and Qa was confirmed (p < 0.05). While performing higher bending moments in all the tested implants, Qa was higher than it could be provided by the body weight. It was the highest in Gamma Nail, and the lowest in SIF-10. CONCLUSIONS: A larger contact surface between a sliding screw and stem results in lower forces required to initiate dynamization of a sliding screw. Patients treated for a pertrochanteric fracture by a sliding screw internal fixation who have longer femoral neck or higher body weight could have different programme of early postoperative rehabilitation than lighter patients or patients with shorter femoral neck.

Effect of different fabrication workflows on the passive fit of screw-retained bar splinting two interforaminal implants: a parallel blinded randomised clinical trial.

BACKGROUND: To clinically compare the effect of the conventional and the digital workflows on the passive fit of a screw retained bar splinting two inter-foraminal implants. METHODS: The current study was designed to be a parallel triple blinded randomised clinical trial. Thirty six completely edentulous patients were selected and simply randomized into two groups; conventional group (CG) and digital group (DG). The participants, investigator and outcome assessor were blinded. In the group (CG), the bar was constructed following a conventional workflow in which an open top splinted impression and a lost wax casting technology were used. However, in group (DG), a digital workflow including a digital impression and a digital bar milling technology was adopted. Passive fit of each bar was then evaluated clinically by applying the screw resistance test using the "flag" technique in the passive and non passive situations. The screw resistance test parameter was also calculated. Unpaired t-test was used for intergroup comparison. P-value < 0.05 was the statistical significance level. The study protocol was reviewed by the Research Ethics Committee in the author's university (Rec IM051811). Registration of the clinical trial was made on clinical trials.gov ID NCT05770011. An informed consent was obtained from all participants. RESULTS: Non statistically significant difference was denoted between both groups in all situations. In the passive situation, the mean ± standard deviation values were 1789.8° ± 20.7 and1786.1° ± 30.7 for the groups (CG) and (DG) respectively. In the non passive situation, they were 1572.8° ± 54.2 and 1609.2° ± 96.9. Regarding the screw resistance test parameter, they were 217° ± 55.3 and 176° ± 98.8. CONCLUSION: Conventional and digital fabrication workflows had clinically comparable effect on the passive fit of screw retained bar attachments supported by two dental implants.

Comparative Short-Term Outcomes of Femoral Neck System (FNS) and Cannulated Screw Fixation in Patients with Femoral Neck Fractures: A Multicenter Study.

Background: Femoral neck fractures need to be treated in their early stages with accurate reduction and stable fixation to reduce complications. The authors compared the early radiologic outcomes of femoral neck fractures treated with the recently introduced Femoral Neck System (FNS, Depuy-Synthes) with conventional cannulated screws (CS) in a multicenter design. Furthermore, the factors associated with early failure after FNS were analyzed. Methods: The FNS group included 40 patients treated between June 2019 and January 2020, and the CS group included 65 patients treated between January 2015 and May 2019. The operation was performed in 3 university hospitals. Patient demographics, fracture classification, postoperative reduction quality, sliding distance of FNS or CS, union and time to union, and complication rates were examined. Logistic regression analysis was performed on candidate factors for early failure of the FNS group. Results: The FNS group had a 90% union rate and a mean time to union of 4.4 months, while the CS group had similar results with an 83.1% union rate and a mean time to union of 5.1 months. In the subgroup analysis of Pauwels type III fractures, the union rates were 75.0% and 58.8% in the FNS and CS groups, respectively, and the time to union was significantly shorter in the FNS group with 4.8 months compared to 6.8 months in the CS group. Early failure rate within 6 months of FNS fixation was observed to be 10%, which included 3 reduction failures and 1 excessive sliding with a broken implant. Risk factors for early failure after FNS were identified as displaced fractures (Garden classification type III or IV), poor reduction quality, longer tip-apex distance, greater sliding distance, and 1-hole implants, of which sliding distance was the only significant risk factor in multivariate analysis. Conclusions: In femoral neck fractures, FNS and CS did not show significant differences for short-term radiologic results. FNS resulted in shorter operative time than cannulated screw fixation and favorable outcomes in Pauwels type III femoral neck fractures. The FNS could be considered a reliable and safe alternative to CS when treating femoral neck fractures.

Bilateral Slipped Capital Femoral Epiphysis in a Young Girl Treated With Chemotherapy: A Case Report.

CASE: A 1-year-old girl was treated with chemotherapy and hematopoietic stem cell transplantation because of CD40 ligand deficiency. Four years later, she presented with pain in her right leg, diagnosed as atypical acute slipped capital femoral epiphysis, without a clear cause, besides chemotherapy possibly. She was treated with fixation of the epiphysis with a cannulated screw. Two years later, the same diagnosis was made for the left hip and the same surgery was applied. After the 2-year follow-up, clinical outcomes were good. CONCLUSION: Chemotherapy may be a risk factor for atypical slipped capital femoral epiphysis, even without the combination with radiotherapy.

Clinical efficacy and complications of blocking screw in the treatment of lower limb long bone fracture: An updated systematic review and meta-analysis.

BACKGROUND: Blocking screw technique has been widely applied in the treatment of long shaft fractures. However, the evidence with regard to whether intramedullary nail combined with blocking screw technique has better clinical efficacy over other is not clear. The aim of the study was to explore the clinical efficacy and complications of intramedullary nail combined with blocking screw technique in the treatment of femoral or tibial shaft fractures. METHODS: The PuMed, Embase, OVID, Cochrane library, Web of Science, Wanfang, CNKI and Weipu data were searched for studies of intramedullary nail combined with blocking screw in treatment of femoral or tibial shaft fracture published up to Aug 31 2023. Methodological quality of the trials was assessed, relevant data were extracted, and RevMan 5.3 and Stata 15.0 software were used to perform the meta-analysis of parameters related to the consequences. RESULT: Twenty articles were included, including 1267 patients. Meta-analysis results showed that compared with the non-blocking screw group, the blocking screw group had longer operation time (WMD = 13.24; 95% CI = 5.68-20.79, P = .0006) and more intraoperative fluoroscopy times (WMD = 57.62; 95% CI = 25.82-89.42, P = .0002). However, the postoperative therapeutic response rate was higher (OR = 5.60; 95% CI = 2.10-14.93, P = .0006), postoperative ankle joint function was better (OR = 3.48; 95% CI = 1.20-10.13, P = .02), and fracture healing rate was higher (OR = 3.56; 95% CI = 1.43-8.89, P = .006), fracture healing time was shorter (WMD = -3.59; 95% CI = -4.96 to -2.22, P < .00001), intraoperative blood loss was less (WMD = -54.80; 95% CI = -88.77 to -20.83, P = .002), hospitalization time was shorter (WMD = -1.66; 95% CI = -2.08 to -1.24, P < .00001), and complications were less (OR = 0.38; 95% CI = 0.16-0.89, P = .01). There was no statistical significance in the range of motion of knee joint between the 2 groups (WMD = 10.04; 95% CI = -1.51 to 21.59, P = .09). CONCLUSIONS: Current evidence shows that intramedullary nail combined with blocking screw technique in the treatment of lower limb long bone fracture has the advantages of good clinical efficacy, high fracture healing rate, short fracture healing time, good joint function, less complications and so on, which is worthy of clinical recommendation.

Diamond-Like Carbon Coating Reduces Connection Screw Head Stripping After Multiple Tightening Instances.

The stability of implant-abutment joint is fundamental for the long-term success of implant rehabilitation. The screw loosening, fracture, and head deformation are among the most common mechanical complications. Several surface treatments of titanium screws have been proposed to improve their resistance and stability. Diamond-like carbon (DLC) coating of the materials is widely used to increase their wear resistance and durability. The present study aimed to evaluate the effect of carbon fiber coating on the screw head on screw removal torque and screw head stripping. One hundred titanium implant screws were used, 50 without coating (Group 1) and 50 with DLC coating of the screw head (Group 2). Each screw was tightened with a torque of 25 Ncm and unscrewed 10 times. The removal torque was measured with a digital cap torque tester for each loosening. Optical 3d measurement of the screw head surface was performed by a fully automatic machine before and after multiple tightening to investigate surface modifications. The reverse torque values decreased with repeated tightening and loosening cycles in both groups without significant differences (P > .05). Optical measurements of surface dimensions revealed average changes of 0.0357 mm in Group 1 and 0.02312 mm in Group 2, which resulted to be statistically significant (P < .001). The DLC coating of the retention screw head can prevent its distortion and wear, especially after multiple tightening.

Retrospective Analysis of Radiographic Outcomes After Closing Base Wedge Osteotomy for Correction of Bunion Deformity.

BACKGROUND: Closing base wedge osteotomy (CBWO) is a common procedure to correct severe bunion deformities with high intermetatarsal angles. There are few data demonstrating the radiographic success of CBWOs. METHODS: We evaluated the radiographic outcomes of a CBWO. The primary aim was to assess the change in elevatus after a CBWO. Secondary aims included measuring the change in hallux abductus (HA) and intermetatarsal angles after the osteotomy. The medical records of 24 consecutive patients across 4 years were reviewed. All of the CBWOs were fixated with either one screw and one Kirschner wire or two screws. We hypothesized that the CBWO would reduce the amount of elevatus present. RESULTS: The mean patient age was 35 years. Average preoperative HA and intermetatarsal angles were 35.2° and 15.7°, respectively. Mean postoperative HA and intermetatarsal angles at last radiographic follow-up were 13.3° and 6.1°, respectively. The change in HA and intermetatarsal angles was 21.9° and 9.6°, respectively. All of the patients achieved clinical union. Mean radiographic follow-up was 6 months; median radiographic follow-up was 5 months. The mean preoperative elevatus measurement was 3.5 mm; the mean postoperative elevatus measurement was 2.0 mm (difference, -1.6 mm; P = .0282), indicating that the osteotomy plantarflexed the first metatarsal. Three patients had radiographic evidence of postoperative elevatus; they were asymptomatic at the last clinical follow-up. CONCLUSIONS: Although clinical concern persists for the development of postoperative elevatus with CBWO, this case series showed plantarflexion of the CBWO. The CBWO is a powerful yet stable procedure for severe bunion deformities and should be viewed as a viable alternative to the Lapidus procedure.

[Orthopaedic robot assisted closed reduction and cannulated screw internal fixation for the treatment of femoral neck fractures].

OBJECTIVE: To investigate the preliminary clinical effect of closed reduction and cannulated nail internal fixation for femoral neck fracture assisted by robot navigation and positioning system. METHODS: From July 2019 to January 2020, 16 cases of femoral neck fracture （navigation group） were treated with closed reduction and internal fixation guided by robot system, including 7 males and 9 females, aged 25 to 72 years old with an average of （53.61±5.45） years old；Garden classification of fracture：3 cases of typeⅠ, 3 cases of typeⅡ, 8 cases of type Ⅲ, 2 cases of type Ⅳ. Non navigation group （control group）：20 cases of femoral neck fracture were treated with closed reduction and hollow nail internal fixation, 8 males and 12 females, aged 46 to 70 years old with an average of （55.23±4.64） years old；Garden typeⅠin 2 cases, typeⅡin 4 cases, type Ⅲ in 11 cases, type Ⅳ in 3 cases. The operation time, fluoroscopy times, guide needle drilling times, screw adjustment times, intraoperative bleeding volume and other indicators of two groups were evaluated. RESULTS: Both groups were followed up for 12 to 18 months with an average of （15.6±2.8） months. The fractures of both groups were healed without delayed union and nonunion. There was no significant difference in healing time between two groups（P=0.782）. There was no significant difference in Harris scores between two groups at the last follow-up（P=0.813）. There was no significant difference in operation time between two groups（P>0.05）. There were significant differences between two groups in fluoroscopy times, guide needle drilling times, hollow screw replacement times, and intraoperative bleeding volume（P<0.05）. CONCLUSION: Closed reduction and hollow screw internal fixation assisted by robot navigation system for femoral neck fracture has the advantages of minimally invasive operation, precise screw placement, and reduction of X-ray radiation damage during operation.

[Comparison of the efficacy of TiRobot orthopaedic robot assisted F screw technique and inverted triangle parallel nail internal fixation in the treatment of unstable femoral neck fractures].

OBJECTIVE: To compare the effectiveness of TiRobot assisted F screw technique and inverted triangle parallel nail internal fixation in the treatment of unstable femoral neck fractures. METHODS: A retrospective analysis was conducted on 72 patients with unstable femoral neck fractures who were treated with percutaneous cannulated screw fixation assisted with TiRobot Orthopaedic robot from December 2019 to April 2021. Among them, 37 patients were treated with F screw internal fixation, including 16 males and 21 females, aged 47 to 64 years old with an average of （53.87±5.28） years old；According to Pauwels classification, there were 1 case of type Ⅰ, 19 cases of type Ⅱ, 17 cases of type Ⅲ；8 cases of combined medical diseases；17 cases of falling, 8 cases of traffic accident and 12 cases of falling from height；The time from injury to operation was 29 to 49 hours with average of （35.00±7.34） hours. Another 35 cases used internal fixation with an inverted triangle parallel nail, including 13 males and 22 females with an average age of 46 to 63 years old （52.36±5.05） years old；According to the Pauwels injury classification：there were 2 cases of type Ⅰ, 21 cases of type Ⅱ, 12 cases of type Ⅲ；6 cases of medical diseases, 15 cases of falling injury, 9 cases of traffic accident, 11 cases of falling injury；The time from injury to operation was 30 to 45 hours with an average of （33.00±6.83） h. The intraoperative blood loss, operation time, intraoperative fluoroscopy times, follow-up time, fracture healing time, postoperative complications were observed and compared between the two groups. The hip joint function was evaluated by Harris score at 6 months and 12 months after operation. RESULTS: There was no significant difference in operation time, intraoperative blood loss, intraoperative fluoroscopy times and other intraoperative data between two groups（P>0.05）. Both groups were followed up regularly, and the follow-up time was 12 to 16 months. The fracture healing time and Harris score of the F screw internal fixation group were better than those of the inverted triangle parallel nail internal fixation group （P<0.05）. There was 1 case of femoral neck shortening in the F screw internal fixation group, 1 case of nonunion, 1 case of nail withdrawal, and 1 case of lower extremity deep vein thrombosis in the inverted triangle internal fixation group. The incidence of complications in the F screw internal fixation group was lower than that in the inverted triangle parallel nail internal fixation group（P<0.05）. CONCLUSION: Percutaneous cannulated F screw technique using Tirobot navigation positioning system is a safe and effective treatment for patients with unstable femoral neck fractures. It can significantly shorten the fracture healing time, reduce the incidence of postoperative complications, significantly improve hip joint function, and improve the quality of life.

Treatment of Pauwels III femoral neck fracture in young patients using biplane double support screw internal fixation technology based on X-ray image.

Traditional treatment methods have certain limitations. In recent years, the technique of internal fixation with double-plane double-supported screws based on X-ray images has been proposed to improve the therapeutic effect. The main objective of this research was to examine the effectiveness of the X-ray image-based bi-planar double-braced screw internal fixation technique . During surgery, the procedure was determined based on X-ray images, followed by an open reduction procedure at the fracture site, and finally internal fixation using bi-planar double-support screws. All patients were successfully treated with X-ray image-based bi-planar double support screw fixation. After surgery, X-ray images showed a good reduction of the fracture site without significant loosening or failure of the internal fixation. At the postoperative follow-up, the patient's pain symptoms were significantly relieved, and no significant complications occurred during recovery.

New design of interdental rubber picks - does the archimedean screw design bring an improvement for experimental cleaning efficacy and force?

BACKGROUND: Up to date, interdental brushes (IDB) are the first choice for interdental cleaning because of their cleaning efficacy. Cylindrical ones must be selected individually according to the size/morphology of the interdental area (IDR), whereas conical ones cover a larger variability of IDR. However, there is a trend on the part of patients towards interdental rubber picks (IRP) which are in general conically shaped, and which seem to be linked with lower cleaning efficacy. A new IRP with an Archimedes´ screw design was developed to overcome this limitation. Therefore, the in vitro study aimed to measure the experimental cleaning efficacy (ECE) and force (ECF) during interdental use of IDBs versus the new IRP type. METHODS: Three IRPs with different tapers (PHB angled: 0.039, PHB straight S: 0.027, Vitis straight M: 0.045; all Flexipicks, Dentaid, Cerdanyola del Vallès, Spain) were compared to one IDB (Interprox micro PHD 0.9, Dentaid, Cerdanyola del Vallès, Spain). IDR were reproduced by a 3D-printer (Form2, Formlabs Sommerville, MA, USA) according to human teeth and matched to equivalent pairs (isosceles triangle, concave, convex) in three different diameters (1.0 mm,1.1 mm,1.3 mm). Covered with simulated biofilm, pre-/ post-brushing situations of IDR (standardized, computer-aided ten cycles) were photographed and quantified by digital image subtraction to calculate ECE [%]. ECF were registered with a load cell [N]. Statistically significant differences were detected using the Mann-Whitney-U-test and the Kruskal-Wallis-test with Bonferroni correction for multiple testing. RESULTS: Overall, the ECE (mean ± SD) was higher for IDB micro 0.9 (45.95 ± 11.34%, p < 0.001) compared to all IRPs (PHB angled: 25.37 ± 15.29%; PHB straight: 22.28 ± 16.75%; Vitis straight: 25.24 ± 12.21%; p ≤ 0.001), whereat best ECE was achieved in isosceles triangle IDR of 1.0-1.1 mm (IDB micro 0.9: 70.7 ± 7.7%; PHB angled S: 57.30 ± 4.43%; p < 0.001). The highest ECF occurred for Vitis straight M with 2.11 ± 0.46 N, while IDB micro 0.9 showed lowest ECF values (0.64 ± 0.14 N; p < 0.001). CONCLUSIONS: IRP with an Archimedes´ screw design and a higher taper were associated with advanced ECE but also higher ECF, nevertheless, ECE didn't reach the cleaning efficacy of conventional IDBs.

Increasing the angle between caudal screw and the transverse plane may aggravate the risk of femoral head necrosis by deteriorating the fixation stability in patients with femoral neck fracture.

Necrosis of the femoral head is the main complication in femoral neck fracture patients with triangle cannulated screw fixation. Instant postoperative fixation instability is a main reason for the higher risk of femoral head necrosis. Biomechanical studies have shown that cross screw fixation can effectively optimize fixation stability in patients with proximal humerus fractures and pedicle screw fixation, but whether this method can also effectively optimize the fixation stability of femoral neck fractures and reduce the corresponding risk of femoral head necrosis has yet to be identified. In this study, a retrospective review of imaging data in femoral neck fracture patients was performed. The cross angle between the femoral neck and the caudal cannulated screw was reported; if the angle between the screw and the transverse plane increased, it was recorded as positive; otherwise, it was recorded as negative. Angle values and their corresponding absolute values were compared in patients with and without femoral head necrosis. Regression analysis identified potential risk factors for femoral head necrosis. Moreover, the biomechanical effect of the screw-femoral neck angle on fixation stability was also verified by numerical mechanical simulations. Clinical review presented significantly larger positive angle values in patients with femoral head necrosis, which was also proven to be an independent risk factor for this complication. Moreover, fixation stability progressively deteriorated with increasing angle between the caudal screw and the transverse plane. Therefore, increasing the angle between the caudal screw and the transverse plane may aggravate the risk of femoral head necrosis by deteriorating the fixation stability in patients with femoral neck fracture.

Choosing the proper implant for extra-articular fractures of proximal phalanges: A study on 75 cases.

INTRODUCTION: Phalangeal fractures are the most common fractures of the hand and in particular the proximal phalanx of the long fingers is the most involved. These fractures can ben conservatively managed but, when the fracture pattern is considered unstable, surgical treatment is recommended. However, there is no consensus in literature about the proper surgical option for extra-articular proximal phalanx fractures. MATERIAL AND METHODS: We compared clinical and radiographical results after treatment of 75 cases of extra-articular proximal phalanx fractures using three different surgical techniques: closed reduction and internal fixation (CRIF) with Kirschner wires (G1 group), open reduction internal fixation (ORIF) with plates and screws or lag screws (G2 group), and closed reduction and intramedullary screw fixation (CRIMEF)(G3 group). RESULTS: We found no significant differences in term of union rate and time to fracture healing between the three groups. However, we found a significant reduction in time to return at work and in TAM at the final follow-up examination in G3 group (treated with CRIMEF) when compared with both G1 and G2. No differences in complications rate were found between three groups. DISCUSSION: The surgical variability in the management of extra-articular phalanx fractures create lacks on standard guide for treatment. CONCLUSIONS: In conclusion, our results showed good clinical and radiographical results with all the three surgical options. However, the closed reduction and internal fixation with intramedullary screws (CRIMEF) seems to be better in terms of time to return to work and TAM at the final follow-up, probably due to good primary stability and little risk of soft tissue adherence development.