Inverted triangle cannulated screw assisted transverse lag screw and femoral neck system fixation for Pauwels Ⅲ femoral neck fractures / 中国组织工程研究

BACKGROUND:Pauwels Ⅲ femoral neck fracture is a typical unstable fracture characterized by high vertical shear force and high incidence of postoperative complications.At present,there are many fixation methods for Pauwels Ⅲ fracture,and there is no clear conclusion as to which internal fixation is the best fixation method for Pauwels Ⅲ femoral neck fracture in young adults. OBJECTIVE:To compare the clinical effect of three inverted triangle cannulated screws assisted transverse lag screws and femoral neck system in fixing Pauwels Ⅲ femoral neck fractures of young adults. METHODS:From May 2021 to December 2022,21 young and middle-aged patients with Pauwels Ⅲ femoral neck fracture were treated with three inverted triangle cannulated screws assisted by transverse lag screws and femoral neck system in Affiliated Hospital of Southwest Medical University.Of them,9 patients were treated with three inverted triangle cannulated screws and one transverse lag screws perpendicular to the fracture line as the 3+1 cannulated screw group and 12 patients were treated with femoral neck system as the femoral neck system group.The two fixation methods were compared in terms of operation time,intraoperative blood loss,total incision length,intraoperative fluoroscopy times,fracture healing time,and limb function. RESULTS AND CONCLUSION:(1)All patients were followed up.Patients in the 3+1 cannulated screw group were followed up for 10-25 months,with a mean of(17.44±4.30)months.The patients in the femoral neck system group were followed up for 8-24 months,with a mean of(15.58±4.68)months.(2)The intraoperative fluoroscopy times and Harris score at 3 months postoperatively in the femoral neck system group were better than those in the 3+1 cannulated screw group,and the difference was statistically significant(P<0.05).The intraoperative blood loss,total incision length,and femoral neck shortening distance in the 3+1 cannulated screw group were better than those in the femoral neck system group,and the differences were statistically significant(P<0.05).There was no significant difference in operation time,fracture healing time,and Harris score at the last follow-up between the two groups(P>0.05).(3)It is indicated that three inverted triangle cannulated screws assisted transverse lag screw and femoral neck system can achieve good clinical effects in the treatment of young and middle-aged Pauwels Ⅲ femoral neck fracture.The femoral neck system has fewer intraoperative fluoroscopy times and better early overall stability,while the 3+1 cannulated screw is more minimally invasive,easier to operate.Both fixation methods are worthy of clinical application and promotion,and can be selected according to the actual clinical situation.

Effect of lag screw and support plate through axillary approach for the treatment of Ideberg typeⅡscapular pelvis fracture / 中国骨伤

OBJECTIVE@#To analyze the effect of lag screw and support plate through axillary approach for the treatment of Ideberg typeⅡscapular pelvis fracture.@*METHODS@#From January 2016 to June 2021, 26 patients with Ideberg typeⅡglenoid fractures were treated with trans-axillary lag screw combined with supporting plate, including 15 males and 11 females. The age ranged from 21 to 75 years, with an average of (43.12±6.56) years old. The Constant-Murley Shoulder joint Scale and University of California at Los Angeles (UCLA) score were used to evaluate the function and clinical efficacy of shoulder joint.@*RESULTS@#All patients were followed up, and the duration ranged from 19 to 42 months, with an average of (30.6±10.5) months. One year after surgery, the Constant-Murley score increased from preoperative 34.9±2.5(ranged, from 28 to 47) to 87.2±6.8(ranged, from 70 to 95). The UCLA score improved from preoperative 17.9±1.7(9 to 25) to 33.1±2.3(29 to 35). Seventeen patients got an excellent result, with 7 good, and 2 fair. None of the patients had infection, screw, and plate loosening, fracture, and other complications after surgery. Two patients had different degrees of Chronic pain in the shoulder during the follow-up period.@*CONCLUSION@#The treatment of Ideberg typeⅡscapular glenoid fractures through axillary approach with lag screws and supporting steel plates has the advantages of convenient exposure, direct visual restoration of the normal anatomical shape of the scapular glenoid, selection of suitable positions for screw and steel plate placement, achieving better treatment results, and fewer complications. It is an effective and reliable surgical method.

A clinical study on the relationship of the tail femur distance and the lag screw migration or cutting-out after the third generation of Gamma nail fixation of intertrochanteric fracture / 中国修复重建外科杂志

Objective: To confirm the association between tail femur distance (TFD) and lag screw migration or cutting-out in the treatment of intertrochanteric fracture with the third generation of Gamma nail (TGN).

Implicit Dynamic Analysis on Tightening Procedure of Cancellous Lag Screw Placement / 医用生物力学

Objective To simulate the tightening procedure of a cancellous lag screw by using the implicit dynamic analysis method, and to evaluate the stress distributions on the screw-bone interface. Methods Finite element models of a lag screw with the surrounding bone were developed, and the implicit solver was set up for implicit dynamic analysis on the tightening procedure of the lag screw. The mechanical properties of the screw-bone interface were also analyzed according to strain and stress distributions on the screw and the surrounding bone. Results The stress of the lag screw was mainly distributed in the proximal portion of the screw thread rod. The high-stress region of the bone around the screw was located outside the outer edge of the screw, and it was approximately equal to the depth of the thread. The area of high-stress distributions on the bone was the main region that resisted screw stripping. Conclusions The method of implicit dynamic analysis can accurately simulate the mechanical properties of the screw-bone interface during screw tightening. The discovery of high-stress distributions on the surrounding bone can help researchers to further understand and improve the stability of screw insertion.

Failure of a Rotation Control Gamma 3 Lag Screw Used to Treat a Trochanteric Fracture / 대한고관절학회지

Gamma 3 rotation control lag screws (U-blade) are particularly useful when treating rotational and unstable fractures of the proximal femur. A 93-year-old woman who underwent closed reduction of a trochanteric fracture and internal fixation with a Gamma 3 nail rotation control lag screw. The patient presented with metal failure and U-blade bending following a fall occurring 4 weeks after surgery. Here, we present a case report summarizing removal of the failed lag screw.

Breakage of the Tail Portion of the Lag Screw during Removal of Proximal Femoral Zimmer Natural Nail: Report of Two Cases with Technical Notes / 대한고관절학회지

Proximal femoral cephalomedullary nailing is one of the treatments of choice for intertrochanteric fracture. Zimmer Natural Nail® (ZNN; Zimmer) is one of the alternatives. We report two cases of broken tail portion of the ZNN lag screw during the removal procedure. This may be the first reported cases in scientific literature with this pattern of failure. We report these cases to highlight one of the possible problems that could occur during removal of this implant which can possibly prolong the operation time significantly if the required device is not prepared.

Breakage of the Tail Portion of the Lag Screw during Removal of Proximal Femoral Zimmer Natural Nail: Report of Two Cases with Technical Notes / 대한고관절학회지

Proximal femoral cephalomedullary nailing is one of the treatments of choice for intertrochanteric fracture. Zimmer Natural Nail® (ZNN; Zimmer) is one of the alternatives. We report two cases of broken tail portion of the ZNN lag screw during the removal procedure. This may be the first reported cases in scientific literature with this pattern of failure. We report these cases to highlight one of the possible problems that could occur during removal of this implant which can possibly prolong the operation time significantly if the required device is not prepared.

Intrapelvic Penetration of Lag Screw in Proximal Femoral Nailing: A Case Report

Hip fractures are common among elderly individuals. Internal fixation with the intramedullary system has been widely used to treat intertrochanteric femur fractures. The Gamma 3 nail is a useful device for fixating trochanteric fractures of the proximal femur. We report a rare complication of medial pelvic penetration of the lag screw of a Gamma 3 nail two months after surgery. There was a complete separation between the nail body and lag screw, and the lag screw penetrated through the acetabulum into the pelvis. We report a case of unstable intertrochanteric fracture with intrapelvic penetration after surgical treatment with proximal femoral nailing and a case followed by fatal results.

Biomechanical Comparison of Inter-fragmentary Compression Pressures: Lag Screw versus Herbert Screw for Anterior Odontoid Screw Fixation

OBJECTIVE: The purpose of the present study was to compare inter-fragmentary compression pressures after fixation of a simulated type II odontoid fracture with the headless compression Herbert screw and a half threaded cannulated lag screw. METHODS: We compared inter-fragmentary compression pressures between 40- and 45-mm long 4.5-mm Herbert screws (n=8 and n=9, respectively) and 40- and 45-mm long 4.0-mm cannulated lag screws (n=7 and n=10, respectively) after insertion into rigid polyurethane foam test blocks (Sawbones, Vashon, WA, USA). A washer load cell was placed between the two segments of test blocks to measure the compression force. Because the total length of each foam block was 42 mm, the 40-mm screws were embedded in the cancellous foam, while the 45-mm screws penetrated the denser cortical foam at the bottom. This enabled us to compare inter-fragmentary compression pressures as they are affected by the penetration of the apical dens tip by the screws. RESULTS: The mean compression pressures of the 40- and 45-mm long cannulated lag screws were 50.48±1.20 N and 53.88±1.02 N, respectively, which was not statistically significant (p=0.0551). The mean compression pressures of the 40-mm long Herbert screw was 52.82±2.17 N, and was not statistically significant compared with the 40-mm long cannulated lag screw (p=0.3679). However, 45-mm Herbert screw had significantly higher mean compression pressure (60.68±2.03 N) than both the 45-mm cannulated lag screw and the 40-mm Herbert screw (p=0.0049 and p=0.0246, respectively). CONCLUSION: Our results showed that inter-fragmentary compression pressures of the Herbert screw were significantly increased when the screw tip penetrated the opposite dens cortical foam. This can support the generally recommended surgical technique that, in order to facilitate maximal reduction of the fracture gap using anterior odontoid screws, it is essential to penetrate the apical dens tip with the screw.

Clinical application and efficacy of lag screw in condylar intracapsular sagittal fracture / 重庆医学

Objective To discuss the applicability and application skills of lag screw in condylar intracapsular sagittal fracture and also to observe its therapeutic effect .Methods We conducted surgical reduction and rigid internal fixation to 21 patients with 27 sides of condylar intracapsular sagittal fracture in department of oral and maxillofacial surgery of the first affiliated hospital of chongqing medical university .Fixation of 24 sides were carried out with lag screw and and the rest sides had condylar bone fragment removal surgeries .Imaging data and clinical symptoms of each side were analyzed before and after the treatment .Results After postoperative follow‐ups in average 17 .4 months ,there were no facial paralysis ,salivary fistula and loose screws in 21 patients .Al‐so ,the recoveries of mouth opening degree and occlusal relationship were satisfactory .There were different degrees of temporoman‐dibular joint disturbances syndrome for the 3 patients with just 1 side done with condylar bone fragment removal surgeries and screw internal fixation before .Seven sides of patients had malocclusion and slight bone absorption in image inspection after surgery . However ,the functions were basically normal .Conclusion Lag screw could be used in condylar intracapsular sagittal fracture and the effect in recovery of the height of ramus and the function of joints is exact .

Breakage of a Lag Screw of Cephalomedullary Nail: A Technique of Removal

A broken lag screw of the cephalomedullary nail is a rare condition. Removal of the retained lag screw from the femoral head is also very challenging. This article describes a surgical technique and the modified instrument that was available in the operating room for removing the broken implant by closed technique.

Presence of a Nail in the Medullary Canal; Is It Enough to Prevent Femoral Neck Shortening in Trochanteric Fracture?

PURPOSE: Presence of a cephalomedullary nail (CMN) in the medullary canal has been thought as advantageous in the control of femoral neck shortening (FNS) and lag screw sliding in trochanteric fracture compared to extramedullary fixation system. However, researches on the factors that influence the degree of FNS after cephalomedullary nailing are lacking. MATERIALS AND METHODS: We observed 95 patients (mean age, 75+/-2.8 years) with trochanteric fractures who were treated with a CMN, and evaluated the relationship between FNS and patient factors including age, gender, fracture type (AO/OTA), bone mineral density, medullary canal diameter, canal occupancy ratio (COR=nail size/canal diameter), and tip-apex distance using initial, immediate postoperative, and follow-up radiography. RESULTS: Univariate regression analyses revealed that the degree of FNS was significantly correlated with fracture type (A1 versus A3, p<0.001), medullary canal diameter (p<0.001), and COR (p<0.001). Multiple regression analyses revealed that FNS was strongly correlated with fracture type (p<0.001) and COR (p<0.001). CONCLUSION: Presence of a CMN in the medullary canal could not effectively prevent FNS in patients with low COR and in A3 type fracture.

Radiographic and functional results of the Hawkins Ⅲ talus neck fractures via internal and lateral approaches / 中国医师进修杂志

Objective To investigate the clinical results and related key points of surgical treatment for Hawkins Ⅲ talus neck fractures.Methods Forty-one patients with Hawkins Ⅲ talus neck fracture were treated.The fractures occurred on the left side in 21 patients and on the right side in 20 patients.All patients were performed internal fixation by internal and lateral approaches.The weight bearing should be adjusted with follow-up.The functional results were evaluated by American Orthopaedic Foot and Ankle Society (AOFAS).Results The average duration of follow-up was (37.7 ± 8.2) months.All fractures gained union and the average union time was (4.1 ±0.5) months.The average AOFAS score after treatment was (79.3 ± 2.6) scores which was higher than that before treatment [(35.1 ± 8.0) scores],and there was significant difference (P =0.026).There were 11 cases in excellent,17 cases in good,11 cases in fair and 2 cases in poor.The excellent and good rate was 68.3％ (28/41).Traumatic arthritis occurred in 18 cases (43.9％,18/41),involved tibial astragaloid joint in 4 cases,involved subtalar joint in 6 cases,involved tibial astragaloid joint and subtalar joint in 8 cases.Avascular necrosis occurred in 7 cases (17.1％,7/41).Conclusions The effect of surgical treatment for Hawkins Ⅲ talus neck fracture via a bilateral approaches is satisfactory.Pay more attention to protect blood circulation intraoperative and perform anatomic reduction according to the characteristic of body of talus displacement.After operation,functional rehabilitation should be directed by the principle of early movement,later weighted.

Suture anchor fixation realizes the physiological reconstruction and repair of tibiofibular syndesmotic injury / 中国组织工程研究

BACKGROUND:The traditional surgical method have large trauma in the treatment of tibiofibular syndesmosis injury, and cannot wel complete the repair of ligament. But the suture anchor has clear effect for ligament repair, ligament reconstruction and bone connection. OBJECTIVE:To investigate the biomechanical properties of the suture anchor in the treatment of tibiofibular syndesmotic injury, and to compare with lag screw internal fixation. METHODS:Eight ankle joint specimens were col ected, and the biomechanical experiment was performed for stress analysis. The suture anchor technology and lag screw internal fixation were used respectively to treat the tibiofibular syndesmotic injury. The biomechanical properties of the stress strength, stiffness and stability were compared. RESULTS AND CONCLUSION:The biomechanical properties of the stress strength, stiffness and stability of suture anchor technology for the treatment of tibiofibular syndesmotic injury were better than those of lag screw internal fixation, and there were significant differences in the strength and stiffness between two methods (P<0.05);the stress shielding rate of suture anchor technology was lower than that of lag screw internal fixation, and the difference was significant (P<0.05);the tibiofibular syndesmosis separated displacement of suture anchor technology was lower than that of lag screw internal fixation, and the difference was significant (P<0.05). The results indicate that the suture anchor technology is a minimal invasion and good method to realize physiological reconstruction and elastic fixation with stable fixation strength and less trauma, and without secondary operation.

Minimally invasive treatment for type-C1 pelvic fracture injured in the earthquake / 中国矫形外科杂志

[Objective]To investigate the possibility of percutaneous minimally invasive technique in treating patients with type C1 pelvic fracture injured in the earthquake.[Method]Thirteen patients with Type C1 pelvic fracture determined by Tile Classification received reduction with external fixation frame for pelvic anterior ring and with cannulated lag screw for pelvic posterior ring fixation guided under C-arm X-ray.[Result]The cannulated lag screw was successfully implanted percutaneously guided under C-arm X-ray,and post-operation X-ray showed satisfactory reduction.[Conclusion]It is an optimum choice for treating C1 pelvic fracture with external fixation frame combined with cannulated lag screw percutaneously implanted under C-arm X-ray.

Treatment of Ankle Lateral Malleolar Fractures Accompanying Osteoporosis using Lag Screw / 대한족부족관절학회지

PURPOSE: To evaluate the results of ankle lateral malleolar fractures classified as Danis-Weber type B accompanying osteoporosis that were treated with lag screw. MATERIALS AND METHODS: 15 cases of Danis-Weber type B ankle lateral malleolar fractures that had T score of less than -2.5 in BMD(bone mineral density) test were selected from June 2003 to December 2005. 10 cases were males and 5 cases were females with mean age of 59 years. The main injury mechanism was supination and external rotation. Mean follow-up period was 16 months. Clinical and radiologic evaluation was done according to Meyer and Kumler's criteria. RESULTS: All cases showed satisfying result and mean radiologic bone union period was 3 months. Anatomic reduction and bone union was acquired in all cases without complications including wound infection, skin necrosis, delayed union and nonunion CONCLUSIONS: Lag screw fixation seem to be excellent treatment of Danis-Weber type B lateral malleolar fractures with osteoporosis as it can minimize soft tissue injury and enable anatomic reduction with firm fixation.

Arthroscopic treatment for avulsion fracture of tibial intercondylar anterior eminence:report of 30 cases / 第三军医大学学报

Objective To investigate the outcomes of arthroscopic reduction and internal fixation with cannulate lag screw for avulsion fracture of tibial intercondylar anterior eminence.Methods From May 2004 to December 2007,30 cases of tibial intercondylar anterior eminence avulsion fracture were treated by arthroscopic reduction and fixation with cannulated lag screw.Among the patients,there were 10 females and 20 males,ranging from 15 to 79 years old with an average age of 32.0.There were 12 fresh fractures and 18 old fractures.According to Meyers-McKeever-Zaricnyl's classification systems,there were 8 cases of type Ⅱ,15 cases of type Ⅲ,and 7 cases of type Ⅳ.Patients were encouraged to do postoperative rehabilitation,such as active joint extension and flexion,exercise of isometric contraction of quadriceps femoris.The treatment outcomes were evaluated by Lysholm and Irrgang knee score system.Results All patients were followed up for 3 months to 60 months(averaging 31.2 months).X rays revealed bony healing 2 months after operation.The joints were stable.Negative Lachaman and drawer and jerk tests were found in all cases,and there was no dysfunction in the knee joints.Lysholm scores were increased from(60.8?1.5)to(95.5?3.5)while Irrgang scores increased from(55.5?3.3)to(90.5?2.5).Conclusion Arthroscopic treatment of avulsion fracture of tibial intercondylar anterior eminence is an easy approach with minimal invasion,and has reliable reduction and fixation with satisfied results.

Clinical Studies Of Lag -Screw Osteosynthesis In Condylar Fractures Of The Mandible

This study evaluated clinical and radiographic results after open reduction and lag-screw fixation of mandibular condyle fractures. PATIENTS AND Methods : 26 patients had been treated by lag-screw fixation for madibular condyle fracures via submandibular approach and follow up for over 6 months. The lag-screw used in this study was designed by Eckelt. Radiographically, resorption of the condyle head found in 4 cases (15%) and minimal displacement of the condyle head was found in 3 cases (12%). Post-operative infection were not found in all cases. Clinically, All patiens had a stable occlusion and normal mouth opening (over 40mm). TMD problems with crepitus or some discomfort encountered in 4 patients but tolerable to the patients. CONCLUSION: Lag screw fixation can be a good option especially high level condylar fractures, however this procedure must be used in cautiously because of slipping of the fragments and possible to resorption of the fragments.

THE OPTIMAL COMPUTER AIDED DESIGN FOR LAG SCREW INTERNAL FIXATION IN THE POSTERIOR COLUMN OF THE ACETABULUM / 解剖学报

Objective To investigate a special optimized technique for computer aided measure,and provide an anatomical basis for the placement of lag screw in the posterior column of the acetabulum. Methods Eighty accurate hemi-pelvis models were reconstructed from 40 CT data sets.The optimization objective function,for improving the placement of lag screw,was built by adaptively sampling the weighted distance of screws to the acetabulum boundary according to surgical requirements,and the two end points of the screw were modified iteratively to reduce the objective value under constraints.The statistical measure data were provided according to new anatomical reference landmarks for clinical use. Results The optimal entry point for lag screw fixation in the posterior column was located(18.90?1.19) mm above the line connecting the anterior borderline of the sacroiliac joint with the notch between the anterior superior iliac spine and the anterior inferior iliac spine,and the connecting line was divided by the perpendicular project point with a proportion of 2∶3.The mean inclination of the lag screw was(85.99?2.04)? for angle with the line connecting the entry point with the notch between the anterior superior iliac spine and the anterior inferior iliac spine,and(37.54?1.55)? for angle with the line connecting the entry point with the perpendicular project point;the mean length of the lag screws in the posterior column was(133.07?3.22)mm.Conclusion The automatic optimized technique for the computer aided measure is very efficient and has many advantages over the conventional manual dissection methods,and is convenient to design new anatomical reference landmark systems for clinical use.