计算机辅助带锁髓内钉远端锁定瞄准系统的设计与实验研究

目的　测试计算机辅助带锁髓内钉远端锁定瞄准系统应用于下肢模型骨及尸体骨固定中的准确性及安全性。方法　采用 10根塑料模型胫骨 ,2 0根塑料模型股骨 (SynboneAG ,Malans,Switzerland) ,6具青年男性新鲜尸体的双下肢标本 ,随机平均分为两组 ,行胫骨、股骨带锁髓内钉内固定术 (Orthofix带锁髓内钉 ,每根针远端有 2孔 )。在远端锁钉时 ,实验组采用计算机辅助带锁髓内钉远端锁定瞄准系统 ;对照组采用Orthofix带锁髓内钉机械锁定瞄准器。两组以远端锁钉锁定的手术操作时间、在C型臂X线下暴露时间、锁定的成功率三项指标进行比较。结果　实验组锁钉锁定的手术时间、X线下暴露时间、锁定成功率分别为 (4 4 4± 2 99)min、(1 16± 0 38)min ,(10 0± 0 ) % ;对照组手术时间、X线下暴露时间、锁定成功率分别为 (10 4 2± 4 18)min ,(4 71± 3 86 )min ,(94 4 4±0 36 ) % ,两组手术与X线下暴露时间显著减少 (P <0 0 5 )。结论　计算机辅助带锁髓内钉远端瞄准系统设计合理、定位准确、操作简便、成功率高、缩短了手术时间 ,特别是在手术中对C型臂X线的依赖程度降低 ,在X线下暴露时间短 ,减少了医患人员的放射损伤。该系统能够通用于各种类型的髓内针 ,便于推广、普及。     

A mechanical distal aiming device for distal locking in femoral nails.

Although the free hand technique remains the most popular method for distal interlocking screw insertion, proximally mounted radiation independent devices that compensate for implant deformation recently have been developed for the femur. However, the benefits of such systems have not been determined. This study prospectively compared the duration of the nailing procedure, the length of radiation time, and the accuracy of interlocking screw placement when using a radiation independent distal aiming system with those using the free hand technique. In 20 paired intact anatomic specimen femurs, one surgeon experienced only in the free hand technique performed statically locked intramedullary nailing using the two methods. For the aiming system and free hand technique, respectively, the total operation time was 19.1 +/- 8.4 minutes versus 20.9 +/- 11.3 minutes, the distal locking time was 6.6 +/- 2.4 minutes versus 4.8 +/- 1.5 minutes, the total fluoroscopy time was 23 +/- 17 seconds versus 69 +/- 34 seconds, and the distal locking fluoroscopy time was 0 versus 37 +/- 15.5 seconds. There were no failures in either group. Drill nail contact and distal screw damage were greater with the free hand technique. This study suggests that the main advantages of the aiming arm compared with the free hand technique include the elimination of radiation during distal interlocking and more precise screw placement with decreased insertion related hardware damage.     

Nail over nail technique for distal locking of femoral intramedullary nails

The free hand technique remains the most popular method for distal locking; however, radiation exposure is a major concern. In an endeavour to overcome this concern, distal locking with the nail over nail technique is evaluated. Seventy patients with femoral diaphyseal fractures treated by intramedullary nailing were divided in two groups for distal locking: either using the free hand technique (group I) or with the nail over nail technique (group II). The average number of images taken to achieve nail insertion without locking, for distal locking, and for the complete procedure in group I was 25.8, 24.2, and 50.08, respectively, compared with 24.8, 4.1, and 28.9, respectively, in group II (statistically extremely significant decrease in radiation). The nail over nail technique appears to be a reliable solution for decreasing radiation exposure during closed femoral intramedullary nailing. However, over-reaming of 1.5 mm is the key to the success of the technique.     

Setscrew distal locking for intramedullary nails: a biomechanical study

OBJECTIVE: This biomechanical study was undertaken to examine the effectiveness of setscrew distal locking in a static intramedullary (IM) femoral nail on the stability of fixation of femoral shaft fractures. DESIGN: Fifteen fresh-frozen cadeveric femora were randomly separated into three groups of five bones and transversely sectioned immediately distal to the isthmus. After the insertion of the large-diameter nails, distal locking was obtained by conventional method in the first group. In the second group, set-screw design was used in which two transverse screws penetrated only the lateral cortex of the femur and compressed the nail in the intramedullary canal. No distal locking was used in the third group. INTERVENTION: All instrumented femurs were mounted on a servohydraulic testing machine and tested in both rotations (20 degrees) and axial compression (amplitude: 1,000 Newton). MAIN OUTCOME MEASUREMENT: Loading-versus-displacement data, acquired at a ten-Hertz sampling rate, were calibrated and used to calculate maximum torque, stiffness, and energy capacity to failure. Maximum displacement and axial stiffness also were determined. RESULTS: Mean maximum torque at 10 degrees for each group were 15.3+/-4.8 newton-meters for the interlocking group, 8.5 +/-1.2 newton-meters for the setscrew group, and 3.6+/-2.7 newton-meters for the nonlocked femora. At 20 degrees of rotational displacement, the torque measured 37.4+/-2.6 newton-meters; 15.0+/-4.0 newton-meters; and 5.3+/-3.1 newton-meters, respectively (p < 0.05). Mean torsional stiffness was 1.17+/-0.76 newton-meters per degree for the setscrew group and 1.34+/-0.83 newton-meters per degree for the interlocking group (p > 0.05). The setscrew design provided 87 percent of the torsional rigidity of the interlocking group. In the axial compression test, mean maximum shortening was 1.1+/-0.3 millimeters in the interlocking group and 1.4+/-0.6 millimeters in the setscrew group (p > 0.05). The mean stiffness on longitudinal compression provided by the interlocking screws and the setscrews was 918 and 860 newton-meters per millimeter, respectively. CONCLUSION: The distal setscrew design provides adequate distal fixation of intramedullary nail for patients in the postoperative rehabilitation period of the femoral shaft fractures treated with intramedullary nailing.     

髁钢板和逆行交锁髓内钉治疗股骨远端粉碎性骨折的疗效比较

股骨远端粉碎性骨折是下肢创伤中较严重的一种,保守治疗效果不佳,手术是治疗此类骨折的主要手段[1],选择合适的内固定方法是取得良好手术效果的关键.     

Biomechanical comparison of humeral nails with different distal locking mechanisms: Insafelock nails versus conventional locking nails

ObjectiveThe aim of this study was to compare the biomechanical resistance to rotational and axial forces of a conventional locking nail with a newly designed intramedullary humeral nail developed for humeral shaft fractures with a secure locking mechanism through the distal part of the nail.MethodsInSafeLOCK humeral nail system (group 1, TST, Istanbul, Turkey) and Expert humeral nail system (group 2, DePuy Synthes, Bettlach, Switzerland) of the same size (9 × 300 mm) were examined. In total, 24 fourth-generation humerus sawbones were used in the experiment. Osteotomy was performed at the humerus shaft, and a defect was created by removing 1 cm of bone. After pre-loading 5000 cycles at a frequency of 2 Hz and a force of 50–250 N for axial loading and 5000 torsion torques between 0.5 Nm and 6.5 Nm at a 2 Hz frequency for torsional loading, the failure load values of each load were recorded. Distal interlocking was performed with an endopin in group 1, while a double cortex screw was used in group 2.ResultsAll samples successfully passed the cyclic loading. The initial and final stiffness values were similar between the groups after axial loading (p = 0.873 and p = 0.522, respectively). The mean axial failure load values in groups 1 and 2 were 2627 ± 164 N and 7141 ± 1491 N, respectively. A significant difference was found in the axial failure load values (p = 0.004). Significant differences were observed between the initial and final torsional stiffness between the two groups (p = 0.004 and p = 0.004, respectively). No significant difference was found in the failure load values after torsional loading (11791 ± 2055 N.mm and 16997 ± 5440 N.mm) (p = 0.055).ConclusionThese results provide a biomechanical demonstration of the adequate stability of both nails after axial and rotational loading. The reliability of the newly developed InSafeLOCK humeral nail system, which does not require fluoroscopic control and an additional incision for distal locking, supports its use in the clinic.     

Radiation educational program significantly reduces intraoperative fluoroscopy time during locking plate fixation for distal radius fractures

BackgroundThe use of C-arm fluoroscopy poses a risk of radiation exposure to the surgeons. This study aimed to examine the intraoperative fluoroscopy time of the distal radius plating before and after radiation educational program.MethodsA total of 68 cases (48 women and 20 men; average age, 61.8 years) were reviewed between July 2017 and October 2019. All patients were treated with volar locking plate fixation for distal radius fractures. On October 2018, we had a 1-h radiation educational program for orthopedic surgeons. Intraoperative fluoroscopy time was compared between 34 cases in the preintervention group (group A) and 34 cases in the postintervention group (group B). Radiographic correction loss of the fracture was assessed by ulnar variance (UV), radial inclination (RI), and volar tilt (VT) between immediately after surgery and at the time of bone union.ResultsA significant difference was found in intraoperative fluoroscopy time between 329 s in group A and 123 s in group B. ΔUV between immediately after surgery and at the time of bone union was 0.6 mm in group A and 0.3 mm in group B; ΔRI was ?0.3° in group A, ?0.1° in group B, ΔVT is ?0.4° in group A, and ?0.1° in group B. No significant difference was found among them.ConclusionsAfter an educational program on radiation exposure, the intraoperative fluoroscopy time was significantly saved in the plating surgery for the distal radius fractures. The shortening of the intraoperative fluoroscopy time did not affect the loss of radiographic correction of the fractures.     

Management of distal femoral periprosthetic fractures by distal femoral locking plate: A retrospective study.

Background:

Management of periprosthetic supracondylar femoral fractures is difficult. Osteoporosis, comminution and bone loss, compromise stability with delayed mobility and poor functional outcomes. Open reduction and internal fixation (ORIF) with anatomic distal femoral (DF) locking plate permits early mobilization. However, this usually necessitates bone grafting (BG). Biological fixation using minimally invasive techniques minimizes periosteal stripping and morbidity.

Materials and Methods:

31 patients with comminuted periprosthetic DF fractures were reviewed retrospectively from October 2006 to September 2012. All patients underwent fixation using a DF locking compression plate (Synthes). 17 patients underwent ORIF with primary BG, whereas 14 were treated by closed reduction (CR) and internal fixation using biological minimally invasive techniques. Clinical and radiological followup were recorded for an average 36 months.

Results:

Mean time to union for the entire group was 5.6 months (range 3-9 months). Patients of ORIF group took longer (Mean 6.4 months, range 4.5-9 months) than the CR group (mean 4.6 months, range 3-7 months). Three patients of ORIF and one in CR group had poor results. Mean knee society scores were higher for CR group at 6 months, but nearly identical at 12 months, with similar eventual range of motion.

Discussion:

Locked plating of comminuted periprosthetic DF fractures permits stable rigid fixation and early mobilization. Fixation using minimally invasive biological techniques minimizes morbidity and may obviate the need for primary BG.     

Two for one: quick, reliable distal locking of intramedullary nails

. Correct closed insertion of an intramedullary nail requires skill and patience. Insertion of distal locking screws to complete the procedure can be demanding and frustrating. A number of techniques to aid this procedure have been described. We present our favoured method which can almost halve the radiation exposure associated with image intensifier use and which is equally applicable to femoral, tibial and humeral nails. Resumé. La mise en place correcte d'un clou centro-médullaire à foyer fermé nécessite adresse et patience. Le positionnement des vis du verrouillage distal pour terminer l'intervention, peut être exigeant et frustrant. De nombreuses techniques pour aider cette procédure ont été décrites. Nous présentons notre méthode favorite, qui peut diminuer de presque moitié l'irradiation associée à l'usage de l'amplificateur de brillance et qui est de la même manière, utilisable pour les clous du femur, du tibia et de l'humérus.     

Intramedullary locking nails for femoral shaft fractures in elderly patients

Fractures of the femoral shaft are generally considered to affect young patients, but we have reviewed 24 cases in patients over 60 years who have been treated by locked nailing, usually by closed methods. Most were women with low-velocity injuries, but despite this, 14 fractures were significantly comminuted. The complication rate was 54% with a peri-operative mortality of 17%. Most complications were the general ones of operating on elderly patients. Specific complications included: fractures below an abnormal hip, proximal fracture related to the nail and poor purchase in the distal femur. In all survivors, the femoral shaft fractures united satisfactorily, and the fixation allowed early mobilisation. The locking nail appears to be an effective method of managing femoral shaft fractures in the elderly patient.     

An alternative direction for proximal locking in retrograde femoral nails

Lateral-to-medial proximal interlocking screw insertion for retrograde femoral nails avoids potential neurovascular injury while maintaining stable interlocking mechanics.     

Accurate and reliable pose recovery of distal locking holes in computer-assisted intra-medullary nailing of femoral shaft fractures: a preliminary study.

OBJECTIVE: One of the difficult steps in intra-medullary nailing of femoral shaft fractures is distal locking - the insertion of distal interlocking screws. Conventionally, this is performed using repeated image acquisitions, which leads to considerable irradiation of the patient and surgical team. Virtual fluoroscopy has been used to reduce radiation exposure, but can only provide multi-planar two-dimensional projection views. In this study, two calibrated fluoroscopic images were used to automatically recover the positions and orientations of the distal locking holes (DLHs). The ultimate goal is to provide precise three-dimensional guidance during distal locking. METHODS: A model-based optimal fitting process was used to reconstruct the positions and orientations of the DLHs from two calibrated fluoroscopic images. No human intervention is required. A preliminary in vitro validation study was conducted to analyze the accuracy and reliability of the technique using images acquired from different viewpoints. The ground truths of the DLH were obtained by inserting a custom-made steel rod through the hole and then digitizing both the top and bottom centers of the rod using a sharp pointer. The recovery errors were computed by comparing the computed results to the ground truths. RESULTS: In all experiments, the poses of the DLHs could be recovered fully automatically. When the recovered positions and orientations of the DLHs were compared to their associated ground truths, a mean angular error of 0.5 degrees (STD = 0.2 degrees ), and a mean translational error of 0.1 mm (STD = 0.0 mm) were found. CONCLUSIONS: Accurate and reliable pose recovery of distal locking holes from two calibrated fluoroscopic images is achievable. Our preliminary in vitro experimental results demonstrate that the recovered poses of the distal locking holes are sufficiently accurate for intra-operative use.     

应力调控型带锁髓内钉治疗股骨骨折的应力水平研究

目的探讨应力调控型带锁髓内钉（SCALN）治疗股骨骨折后应力水平的变化。方法采集12具成人新鲜尸体股骨标本，模拟Panjabi方法制作股骨中段横断骨折模型，将标本分为三组（每组3个标本），分别采用SCALN、第一代自动加压带锁髓内钉（ALN）和普通带锁髓内钉（GK钉）固定，均进行系统生物力学性能测试、应力遮挡分析和应力水平测量，并进行比较。结果与ALN、GK钉相比，SCALN应力-应变关系值分别小14％和18％（P〈0．05）；应力遮挡率分别小10％和66％（P〈0．05）。SCALN刚柔结合弹性动态固定使股骨断端应力水平接近生理性，且手术操作方便。结论SCALN在有效控制骨折端弯、扭、剪、旋有害应力的同时，解决了临床上坚强内固定骨折断端无应力传导的问题，是当前新一代股骨骨折优良的髓内固定器械。     

Retrograde traditional femoral or tibial locked intramedullary nails for distal femoral injuries

Recently, the use of retrograde locked intramedullary nailing has become an increasingly accepted treatment option for distal femoral injuries. A retrograde traditional femoral or tibial locked nail has sometimes replaced a standard supracondylar nail, which has biomechanical disadvantages and a high cost. To date, this modified technique has been reported in few articles, and the suitability and technical points of this method have not been well defined. The aim of this study was to review the related literature, compare the findings with the author's experiences, and then possibly clarify the role of retrograde traditional locked nails in the treatment of distal femoral injuries.