Effect of autocontrol micromotion intramedullary interlocking nail on fracture healing： an experimental study

Objective: To investigate the effect of autocontrol micromotion locking nail ( AMLN ) on experimental fracture healing and its mechanism. Methods: 16 goats undergoing both sides of transverse osteotomy of the femoral shafts were fixed intramedullary with AMLN and Gross-Kempf (GK) nail, respectively. The follow-up time was 7, 14, 28 and 56 days. Roentgenographic, biomechanical, histological, scanning electromicroscopic and biochemical analyses were done. Results: (1) The strength of anticompression, antiflexion and antitorsion in the fractural end in the AMLN-fixed group was higher than that of GK nail-fixed group; whereas, the rate of stress shelter in the fractured end decreased significantly (P<0.01). (2) The content of the total collagen, insoluble collagen, calcium and phosphate in the AMLN-fixed group was higher than that in the GK nail-fixed group (P<0.05). (3) Histological observation and quantitative analysis of calluses revealed that AMLN could promote the growth of bridge calluses and periosteum calluses. Hence the facture healing and remolding process achieved early, which was much better than traditional GK nail fixation. (P<0.05). (4) 7-14 days postoperation, the calluses of AMLN-fixed group was flourish and camellarly arranged and the collagen fibril formed constantly in the absorption lacuna of bone trabecula. 28-56 days postoperation, the collagen fibril was flourish around the absorption lacuna and was parallel to the bone's longitudinal axis. Active bony absorption and formation were seen, so was remolding and rebuilding. Haversian system was intact and the bony structural net was very tenacious because of the deposition of calcium salt. None of the above findings was observed in the GK nailfixed group. Conclusions: The design of AMLN accords well with the plastic fixation theory. As the geometry ametabolic system constituted by the intramedullary fixation instruments and the proximal and distal end of the fracture is very firm and stable, the disturbance to the physical stress distributed in the fractural end is light. The generation and conduct of the intermittent physical stress between the fractural parts could reach the balance between stress conduct and stress protection. The feature that the healing and remolding take place at the same time speeds up the fractural healing process.     

Bending and torsional stiffness in cadaver humeri fixed with a self-locking expandable or interlocking nail system: a mechanical study

OBJECTIVES: This study was designed to gain data about a new expandable, noninterlocked intramedullary nail's capacity to stabilize unstable transverse humeral shaft fractures without the need for interlocking, thus making nail implantation simpler and to prove our goal hypothesis: that in a midshaft osteotomy of the humeral shaft the expandable humeral nail will show the same bending and torsional stiffness as an interlocked humeral nail, when implanted correctly according to the manufacturer's instructions. DESIGN: Pair randomization. SETTING: Mechanical laboratory testing. PARTICIPANTS: Eight pairs of freshly harvested cadaveric humeri. INTERVENTIONS: Fracture model was a midshaft transverse osteotomy, gapped to 3 mm. Each humerus pair received an expandable humeral nail (Fixion) or an interlocked humerus nail (Synthes) through a retrograde approach. The humeri were fixed in polymethylmethacrylate cylinders and tested in a servo-pneumatic material-testing machine. MAIN OUTCOME MEASUREMENTS: Torsional stiffness and bending stiffness of the nail-bone-construction. RESULTS: Expandable nails (interlocked nails) showed a lateral bending stiffness of 0.73 +/- 0.14 (0.63 +/- 0.1) KN/mm (P = 0.026) and a frontal bending stiffness of 0.67 +/- 0.18 (0.58 +/- 0.09) KN/mm (P = 0.084). Torsional stiffness values were 0.13 +/- 0.19 (0.43 +/- 0.09 Nm/degrees) (P = 0.012). Lower torsional stiffness in the expandable nail group was observed in humeri with a funnel shaped proximal intramedullary canal. CONCLUSIONS: The nail systems showed similar characteristics for frontal bending (P = 0.084), but not for lateral bending (P = 0.026). For lateral bending, the Fixion nail showed significantly more stiffness than the UHN nail (P = 0.026). There was significantly lower torsional stiffness with expandable nails compared with interlocked nails. Clinical correlation would suggest that in rotationally unstable fractures (A2 and A3 diaphyseal fractures), interlocked nails would provide increased stability over expandable nails.     

Subtrochanteric femur fractures: a comparison of the Zickel nail, 95 degrees blade plate, and interlocking nail.

Seventy-nine nonconsecutive patients with subtrochanteric femur fractures were divided into three groups based on the method of fracture fixation. Group I consisted of 21 patients treated with a Zickel nail, Group II comprised 25 patients treated with a 95 degrees blade plate, and Group III included 33 patients treated with an interlocking nail. All patients in Group I and Group II had open reduction and internal fixation of their fractures. Ninety-four percent of the patients in Group III were treated by closed intramedullary nailing. The average operating times for Groups I, II, and III were 212, 272, and 181 min, respectively, while blood loss averaged 900, 1,500, and 600 ml for each group, respectively. Group I had one infection, ten malunions, and one nonunion. Group II had one infection, six malunions, and two nonunions. Group III had no infections, two malunions, and one nonunion. We conclude that closed interlocking nailing is the treatment of choice for acute nonpathologic subtrochanteric femur fractures in adults. There is decreased blood loss, reduced operating time, and fewer complications than with either the Zickel nail or the 95 degrees blade plate regardless of the fracture pattern or the degree of fracture comminution.     

股骨干骨折髓内钉远端徒手锁钉技术及应用解剖学研究

目的:探讨股骨干骨折髓内钉固定时远端徒手锁钉的可行性。方法:选取成人不成对股骨防腐标本22根,对12根标本远端锁钉横截面的周径、外侧边边长及外侧上下角进行测量。选最大截面运用平面几何与三角函数来计算探针通过截面外侧边上探测孔的最大摆动角并确定探测孔的最佳定位点。用直径1mm的克氏针经过直径4mm的探测孔来探测直径为9mm的髓内钉,并通过10根股骨干骨折模型及15例临床股骨干骨折病例对徒手锁钉法加以验证。结果:股骨干远端锁钉横截面即股骨远端骨骺线上3cm处的横截面,其外周径为(153.00±7.45)mm,外侧边长为(36.30±2.65)mm,外上角为102.42±5.85°,外下角为81.00±3.25°,外侧边髓腔厚度(1.96±0.04)mm。在最大的横截面处当探查孔直径为4mm时,在外侧两边角区存在盲区(即髓内钉位于其间但通过探查孔的探针不能探到的区间)。但当髓内钉通过约10cm的髓腔狭窄段时,髓内钉不会到达盲区。探针向上、向下的最大摆动角均为44°,当探查孔定位于外侧边中点时,如髓内钉通过的10cm的髓腔狭窄段,骨折复位满意时是可以被探针探及的。应用此法在10根标本及14例利用定位器远端锁钉失败的临床病例中获得成功。结论:通过股骨外侧4mm的探查孔用直径1mm的细克氏针滑移来寻找髓内钉徒手锁钉的方法是可行的。     

Intramedullary nailing of the femur with an inflatable self-locking nail: comparison with locked nailing

We report a comparative study between an inflatable expandable nail and a traditional locked intramedullary implant in closed fractures of the femoral shaft. We matched each of 43 patients who had undergone intramedullary fixation with an inflatable expandable nail with a patient of the same sex, age (within 2 years), and fracture who had undergone statically locked intramedullary fixation with traditional nails. The mean duration of surgery was significantly shorter in the patients who were treated with the inflatable expandable nail. There were no differences in average blood loss, transfusion requirements, or hospitalization. Five of the patients who underwent traditional nailing required dynamization to achieve union. The inflatable expandable nail allows effective management of diaphyseal fractures of the femur. Interlocking is not necessary, operative times are reduced, and exposure to ionizing radiation is minimized. At present, however, the inflatable expandable nail used in the this investigation is markedly more expensive than traditional devices.     

可膨胀髓内钉和交锁髓内钉在胫骨干骨折治疗中的比较

目的 对可膨胀髓内钉和交锁髓内钉在胫骨骨折治疗中的相关因素进行比较分析。方法 2004年6月至2005年10月间，收治胫骨干骨折57例，42例行交锁髓内钉固定，15例行可膨胀髓内钉固定。对两组病例的手术时间、术中出血量、术中透视时间、术后并发症、骨折愈合时间进行比较。结果 两组在手术时间、术中出血量、术中透视时间、骨折愈合时间等方面差异有统计学意义（P〈0．05），在术后并发症上无显著性差异（P〉0．05）。因此可膨胀髓内钉组在多方面均优于交锁髓内钉组。结论 可膨胀髓内钉具有操作方便、创伤小、愈合快等优点，但费用昂贵，适应症较窄。     

Comparative study on treatment of midshaft tibial fracture with expandable and interlocking intramedullary nails

Objective ： To evaluate the clinical results of treatment of midshaft tibial fracture with expandable intramedullary nails compared with interlocking intramednilary nails. Methods： From June 2003 to August 2005, 46 patients （27 males and 19 females, aged 20-74 years, mean =38.4 years ） with midshaft tibial fracture were treated surgically in our department. The causes of fractures were traffic injury in 21 patients, fall injury in 6, tumbling injury in 11 and crushing injury in 8. According to AO/ ASIF classification, Type A fracture was found in 16 patients, Type B in 11, Type C1 in 5, and Type C2 in 2. Open fractures were found in 12 patients, according to Gustilo classification, Type Ⅰ in 9 patients and Type Ⅱin 3 patients. Based on the patients＇consent, 24 patients were treated with expandable intramedullary nails （Group A ） and 22 with interlocking intramedullary nails （Group B ）. The operation time, blood loss during operation, X-ray fluoroscopic times, hospitalization time, weight bearing time after operation, healing time of fracture and complications of all the patients were recorded. The clinical effects of all the cases were evaluated according to the criteria of Johner-Wruhs. Results： All the patients were followed up for 12,34 months （ mean = 16.2 months）. The time of operation, the blood loss, X-ray fluoroscopic times, hospitalization time and healing time of fracture of Group A significantly decreased （P 〈 0.05 ） compared with those of Group B, but the time for weight bearing after operation, the Johner- Wruhs degree of clinical effects and complications had no significant difference between Group A and Group B （P〉0.05）. Conclusions： Expandable intramedullary nail can shorten operation time, decrease blood loss and reduce invasion, which is a safe and effective treatment method for tibial midshaft fracture.     

Comparative study of the efficacy of gentamicin-coated intramedullary interlocking nail versus regular intramedullary interlocking nail in Gustilo type I and II open tibia fractures

Purpose: Open tibia fracture is prone to infection, consequently causing significant morbidity and increasing the hospital stay, occupational loss and onset of chronic osteomyelitis. Intramedullary nailing is one choice for treating tibia shaft fractures. To improve the delivery of antibiotics at the tissue-implant interface, many methods have been proposed as a part of prophylaxis against infection. This study was conducted to study the role of gentamicin-impregnated intramedullary interlocking (IMIL) nail in the prevention of infection in Gustilo type I and II open tibia fractures and to compare the results with regular intramedullary nail. Methods: The study included 28 patients with open tibia fractures (Gustilo type 1 or type 2); of them 14 underwent regular IMIL nailing and the other 14 were treated with gentamicin-coated nailing. Randomization was done by alternate allocation of the patients. Follow-up was done postoperatively (day 1), 1 week, 6 weeks, and 6 months for bone union, erythrocyte sedimentation rate (ESR), hemo globin and C-reactive protein (CRP). Statistical significance was tested using unpaired t-test. A p value less than 0.05 was considered significant. Results: There were 4 cases of infection in controls (regular IMIL nail) and no infection among patients treated with gentamicin-coated nail during the follow up (X2 = 4.66, p = 0.031). At 6 months post operatively, CRP (p = 0.031), ESR (p = 0.046) and hemoglobin level (p = 0.016) showed significant dif ference between two groups. The bone healing rate was better with gentamicin-coated nail in comparison to regular IMIL nail at 6 months follow-up (p = 0.016). Conclusion: Gentamicin-coated IMIL nail has a positive role in preventing infection in Gustilo type I and II open tibia fractures.     

Numerical evaluation of the mechanical properties of a novel expandable intramedullary nailing: A new alternative to standard interlocking nailing

Introduction: There has been a great effort in preventing the disadvantages of distal locking in intramedullary nailing to date. From this scope, a novel expandable nail fixation eliminating distal locking screws has been designed. The primary aim of this numerical parametric study is to investigate mechanical behavior of expandable nail fixation on the fractured femur model under different contact parameters which are effective in maintaining the nail position and to specify the appropriate values of these contact parameters for a safe fixation. The second aim is to compare mechanical behavior of the expandable nail fixation with the standard interlocking nail fixation.Materials and Methods: The expandable nail has three wedges which are responsible for distal fixation by compressing the medullary canal in the radial direction. 4th generation Sawbones femur model was used as bone model. A transverse osteotomy with 20 mm gap was created to simulate a subtrochanteric fracture. The fixations have been examined under axial compression with 1200 N and torsion with 7 Nm. In the parametric study, the tightening torque and static friction coefficient in wedge-canal contact were selected as contact parameters. The outputs were stiffnesses of the fixations, equivalent von-Mises stress distribution on the models, and load sharing between the canal and distal locking elements.Results: The results of the parametric study showed that the model with the tightening torque of 3 Nm and friction coefficient of 0.7 was the safest. The load borne by wedges is generally prone to increase with increased tightening torque and friction coefficient. The both fixations showed close stiffness and stress values.Conclusion: The tightening torque of the wedge locking mechanism is directly effective in maintaining the nail position constant in canal, and the safety of the fixation is better ensured with increased tightening torque but stress states on bone must be carefully evaluated. The expandable nail provided comparable results to standard interlocking nails with respect to the fixation stiffness, stress, and contact forces. The expandable nailing may be evaluated as an alternative in the fractures of long bones in the case that the numerical results are supported by future experimental studies.     

旋入髓内钉与交锁髓内钉治疗成人股骨干骨折疗效分析

[目的]评价旋入式自锁髓内钉、交锁髓内钌在治疗成人股骨干骨折的临床疗效.[方法]自2005年6月～2010年6月采用旋入式自锁髓内钉、交锁髓内钉治疗成人股骨干骨折53例,男38例,女15例,年龄21～65岁;53例患者中交锁髓内钉固定治疗28例,旋入式自锁钉固定治疗25例,对两组分别就其平均手术时间、骨折平均愈合时间、HSS knee rating score法评定功能的各项指标进行比较分析.[结果]53例均获随访,随访时间6～24个月,平均10个月.交锁髓内钉固定组断钉1例,伤口浅表感染1例,骨延迟愈合3例;旋入式自锁钉固定组骨折延迟愈合1例,骨折短缩移位1例.交锁髓内钉固定组的平均手术时间为(95±10) min,旋入式自锁钉固定组平均(55±10) min.交锁髓内钉固定组骨折平均愈合时间为(22.0±3.5)周;旋入式自锁髓内钉固定组平均骨折愈合时间为(20.0±2.5)周;HSS knee rating score法评定功能恢复优良率:交锁髓内钉固定组(88.5±3.0)%;旋入式自锁髓内钉固定组(92.5±3.60)%.旋入式自锁髓内钉固定组与交锁髓内钉固定组相比,统计学有显著性意义(P<0.05).[结论]旋入式自锁髓内钉结构简单,操作方便快捷,创伤小,疗效可靠,是治疗成人股骨干骨折的有效方法.     

髓内钉内固定系统治疗股骨粗隆间骨折的应用比较

目的探讨Gamma钉、股骨近端髓内钉（PFN）、股骨近端防旋髓内钉（PFN—A）、Fixion—PF型可膨胀髓内钉等4种髓内钉固定系统治疗股骨粗隆间骨折在手术操作难易程度、手术时间、术中出血量及术后骨折愈合和髋关节功能等情况方面的比较。方法对本组134例接受髓内钉系统治疗的股骨粗隆间骨折患者的临床资料进行回顾性分析，其中Gamma钉治疗46例，PFN治疗29例，PFN．A治疗51例，Fixion—PF钉治疗8例。术后复查x线片判断骨折愈合的情况，根据Harris髋关节评分评定关节优良率，并对手术时间、术中失血量、术后骨折愈合时间及髋关节功能情况进行统计学分析。结果PFN—A组的手术时间、出血量少于其他三组（P〈0．05），而PFN、Gamma钉、Fixion．PF钉组三者之间的差异则无统计学意义。134例患者中共有98例得到随访，随访时间平均13．6个月（4—28个月），所有随访患者全部获得骨性愈合，各组愈合时间、关节优良率相比无统计学意义。结论治疗股骨粗隆间骨折的4种髓内钉系统中，PFN—A相对操作简单，手术时间及术中失血量少；但骨折愈合时间及髋关节功能优良率与其他组比较差异无统计学意义。     

可膨胀髓内钉与带锁髓内钉治疗胫骨骨折的疗效分析

目的 观察可膨胀髓内钉与带锁髓内钉治疗胫骨骨折的临床效果,探讨可膨胀髓内钉治疗胫骨骨折的方法及临床适应证.方法 72例胫骨骨折患者随机分为2组, A组:34例,行可膨胀髓内钉内固定术;B组:38例,行带锁髓内钉内固定术.从手术时间、术中出血量、骨折愈合时间和并发症等方面进行比较分析.结果 随访5～13个月,平均7个月.两组疗效比较:手术时间、术中出血量、X线透视时间、骨折愈合时间差异有显著性(P＜0.05),术后并发症差异无显著性(P＞0.05).结论 可膨胀髓内钉内固定治疗胫骨骨折能显著减少手术时间和术中出血量,缩短骨折愈合时间,减少并发症,掌握好手术指征,是治疗胫骨骨折的一种较好方法.     

The Grosse-Kempf interlocking nail: technique of femoral and tibial fractures

An anatomical reduction is required on both the lateral and AP view. In our hands this is easiest obtained and maintained with the patient in the supine position. The supine position facilitates better anesthesia care in the multiply injured patient and aids in movement of the image intensifer during the procedure. Each step should be carefully followed and the horizontal screw placement is possible only when the image of the holes is perfectly round. When the previously mentioned conditions and steps are followed, a successful locking nail insertion can be achieved.     

AO钢板、矩形髓内钉、带锁髓内钉治疗胫骨骨折的比较

目的探讨胫骨骨折内固定物的临床疗效。方法采用ＡＯ钢板治疗５２例,矩形髓内钉１６例,带锁髓内钉３６例,并进行临床随访分析。结果骨折愈合时间ＡＯ钢板组平均８个月,矩形髓内钉组９个月,带锁髓内钉组６个月。ＡＯ钢板组发生伤口感染３例,延迟感染１例,钢板松动３例;矩形髓内钉组发生畸形愈合２例;带锁髓内钉组发生伤口感染１例,远端锁钉松动１例,膝关痛１例。结论带锁髓内钉为轴性及弹性内固定,内固定坚强,为闭合或半     

Biomechanical comparison of distal femoral fracture fixation: Analysis of non-locked,locked, and far-cortical locked constructs

To assess whether far-cortical locking (FCL) screws alter the fracture site strain environment and allow shorter bridge plate constructs for supracondylar femoral fractures, we tested the fracture site displacement under force of synthetic left femora with a 5-cm metaphyseal fracture gap, modeling comminution. Five models of nine constructs were tested (three types of diaphyseal screws [nonlocking, locking, and FCL] and two plate lengths [13 holes and 5 holes]). Long plate models using three or four diaphyseal screws (working length 13.5 or 7.5 cm, respectively) were compared with short plates with three diaphyseal screws (working length 7.5 cm). Models were loaded axially and torsionally; 100 cycles in random order. Primary outcome measures were axial and torsional fracture site stiffness. FCL screws decreased rotational stiffness 19% (P < .01) compared with baseline nonlocking screws in the same plate and working length construct, mirroring the effect (20% decrease in stiffness, P < .01) of nearly doubling the nonlocking construct working length (7.5-13.5 cm). Similarly, FCL screws decreased axial stiffness 23% (P < .01) in the same baseline comparison. Fracture site displacement under loading comparable to a long working length nonlocked plate construct was achieved using a shorter FCL plate construct. By closely replicating the biomechanical properties of a long plate construct, a fracture site strain environment considered favorable in promoting fracture healing might still be achievable using a shorter plate length. Clinical Significance: It might be possible to optimize fracture site strain environment and displacement under loading using shorter FCL plate constructs. Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 00:00–00, 2020.     

Comminuted femoral-shaft fractures: treatment by roller traction, cerclage wires and an intramedullary nail, or an interlocking intramedullary nail

In a retrospective study, we attempted to assess progress in the treatment of comminuted fractures of the femoral shaft at Parkland Memorial Hospital from 1978 to 1983. Seventy-nine comminuted femoral-shaft fractures were available for follow-up: thirty-two treated by roller traction, twenty-three treated by cerclage wires and an intramedullary nail, and twenty-four treated by an interlocking intramedullary nail. Using the classification of Winquist and Hansen, Grade-III and IV comminuted fractures accounted for 69 per cent of those treated by roller traction, 68 per cent of those treated by nailing and cerclage wires, and 96 per cent of those treated by an interlocking nail. The frequency of multiple injuries was 38 per cent in the patients treated by roller traction, 39 per cent in those treated by nailing and cerclage wires, and 58 per cent in those treated by an interlocking nail. The average hospitalization times were thirty-one days for roller traction, sixteen days for cerclage wires and an intramedullary nail, and 19.5 days for an interlocking nail. The average length of follow-up was 132 weeks after roller traction, 115 weeks after cerclage wiring and an intramedullary nail, and sixty weeks after insertion of an interlocking nail. All fractures were followed until after union; the average times to union were 18.4 weeks after roller traction, thirty-four weeks after open reduction and intramedullary nailing with cerclage wires, and 13.8 weeks after insertion of an interlocking nail. For the purposes of this study, treatment was assumed to have failed if a change in treatment was necessary, an unplanned reoperation was performed, femoral shortening exceeded 2.5 centimeters, angulation was more than 15 degrees, non-union or a deep infection developed, motion of the knee was less than 70 degrees of flexion, or a refracture occurred. By these criteria, the frequency of failure after roller traction was 66 per cent (secondary to malalignment and shortening); after insertion of an intramedullary nail with cerclage wires, 39 per cent (secondary to unplanned surgery, non-union, shortening, and infection); and after use of an interlocking nail, 4 per cent (secondary to shortening). Currently, at our institution, an interlocking intramedullary nail is the treatment of choice for comminuted femoral-shaft fractures because it encourages early union with maintenance of length and alignment and the results are predictable.     

闭合复位经皮锁定钢板与交锁髓内钉治疗胫骨干中下段骨折的疗效比较

[目的]评价闭合复位锁定钢板与交锁髓内钉固定治疗胫骨干中下段(距离胫距关节面4~11 cm范围内)骨折的临床和放射学比较。[方法]回顾性分析自2003~2007年采用内侧锁定钢板和交锁髓内钉治疗胫骨干中下段骨折共65例,其中锁定钢板(钢板组)治疗37例、交锁髓内钉(髓内钉组)治疗28例;按AO分型:A型32例,B型12例,C型21例。[结果]对所有病人随访12~24个月,平均16.5个月。5例患者发生延迟愈合或不愈合,其中钢板组1例,髓内钉组4例。钢板组中1例和髓内钉组中2例患者伴发深部感染。钢板组中1例,髓内钉组中8例伴发骨折畸形愈合。钢板组中2例,髓内钉组中8例进行了2次手术。钢板组和髓内钉组功能评估,踝关节功能优良率分别是91.9%、71.4%,膝关节功能优良率分别是97.3%、78.6%。[结论]锁定钢板和交锁髓内钉都能成功的治疗胫骨中下段骨折,但在髓内钉组中骨折延迟愈合、畸形愈合和第2次手术发生率更高。选用锁定钢板能更好的治疗胫骨干中下段骨折。