Femoral Nailing-related Coagulopathy Determined by First-hit Magnitude

We asked whether coagulopathy worsened during femoral intramedullary nailing in the presence of lung contusion and hemorrhagic shock and whether reamed or unreamed nailing influenced these results. In 30 Merino sheep, we induced hemorrhagic shock and/or standardized lung contusion followed by femoral nailing. Six groups of five each were assigned as follows: thoracotomy control groups treated with reamed or unreamed nailing, lung contusion groups treated with reamed or unreamed nailing, and shock and lung contusion groups treated with reamed or unreamed nailing. After lung contusion alone (first hit), the serum values of antithrombin III, factor V, and fibrinogen were considerably altered after reamed and unreamed femoral nailing (second hit) 4 hours postoperatively. In the lung contusion and shock groups, we found a substantial reduction for all serum coagulative parameters between baseline and fixation after reamed and unreamed nailing. The magnitude of the first hit is increased if hemorrhagic shock is added to a lung contusion determined by hemostatic reactions. The magnitude of the injury appears equally important as the type of subsequent surgery and should be considered in planning for fracture fixation in patients at high risk for complications.     

Reamed femoral nailing in sheep: does irrigation and aspiration of intramedullary contents alter the systemic response?

BACKGROUND: Reaming of the femoral canal has been demonstrated to introduce intramedullary contents into the circulation with subsequent pulmonary embolization. The aim of this study was to investigate whether this effect can be minimized by use of a reamer system that provides simultaneous irrigation and aspiration of intramedullary contents. METHODS: A unilateral lung contusion was created and intramedullary femoral nailing was subsequently performed in eighteen female skeletally mature Merino sheep. The animals were divided into three groups, of six animals each, to receive one of three types of treatment: reamed femoral nailing; reaming, irrigation, and aspiration; and unreamed femoral nailing. Blood samples were obtained and a bronchoalveolar lavage was performed at baseline, immediately after creation of the lung contusion, immediately after intramedullary nailing, and at four hours after surgery. Pulmonary permeability, polymorphonuclear leukocyte activity, and systemic hemostatic response were measured. Lung specimens were obtained for histological evaluation. RESULTS: At baseline and immediately after creation of the lung contusion, endothelial permeability was comparable among the three groups. At four hours postoperatively, pulmonary permeability was significantly higher in the group treated with reamed femoral nailing (urea/protein ratio; 256.7) than in the group treated with reaming, irrigation, and aspiration (urea/protein ratio, 91.5) and the group treated with unreamed femoral nailing (urea/protein, 110.64) (p < 0.05). The stimulatory capacity of the polymorphonuclear leukocytes was significantly decreased (p < 0.05) only in the group treated with reamed femoral nailing; the other two groups had no significant decrease postoperatively (p > 0.05). The D-dimer level at four hours postoperatively was significantly higher in the group treated with reamed femoral nailing than it was in the other two groups (p < 0.05). Histological examination showed that the grades of edema and polymorphonuclear leukocyte diapedesis were also highest in the group treated with reamed femoral nailing. CONCLUSIONS: It appears that, in the presence of a unilateral pulmonary injury, the systemic effects of intramedullary reaming of an intact femur can be minimized with use of a modified reamer design that simultaneously irrigates the canal and removes debris. Additional clinical validation of this reaming system is necessary.     

股骨干骨折扩髓与不扩髓固定对肺气体交换功能的影响

目的 :探讨股骨干骨折髓内钉固定过程中扩髓与不扩髓对肺气体交换功能的影响。方法 :38例股骨干骨折分别采用扩髓和不扩髓交锁钉内固定 ,术中不同时间段进行动脉血气分析 ,计算肺泡死腔分数 (Vd/Vt)、氧合指数(PaO2 /FiO2 )。结果 :扩髓组 ,髓腔扩大后Vd/Vt增加 (p <0 .0 5 ) ;PaO2 /FiO2 降低 (p <0 .0 1) ;不扩髓组 ,插入髓钉后30minVd/Vt增加 ( p <0 .0 5 ) ,PaO2 /FiO2 降低 ( p <0 .0 1) ,髓内钉插入后 6 0min时二者在 2组间均恢复正常 ;扩髓后 2组间Vd/Vt、PaO2 /FiO2 差异具有显著性 ,其它时间段 2组间无差异 ;动脉血气分析 ,各时间段和组间差异无显著性。结论 :扩大髓腔的髓内钉固定 ,并不影响肺气体交换功能 ,股骨干骨折患者血流动力学稳定时 ,能耐受扩髓髓内钉固定手术。     

Intramedullary pressure and bone marrow fat extravasation in reamed and unreamed femoral nailing.

This study was designed to investigate whether intramedullary pressure and embolization of bone marrow fat are different in unreamed compared with conventional reamed femoral nailing in vivo. In a baboon model, the femoral shaft was stabilized with interlocking nailing after a midshaft osteotomy. Intramedullary pressure was measured in the distal femoral shaft fragment at the supracondylar region. Extravasation of bone marrow fat was determined by the modified Gurd test (range: 0-5) with blood samples from the vena cava inferior. Data were monitored in eight unreamed and eight reamed intramedullary femoral nailing procedures. Intramedullary pressure increased in the unreamed group to 76 +/- 25 mm Hg (10.1 +/- 3.3 kPa) during insertion of 7-mm nails and in the reamed group to 879 +/- 44 mm Hg (117.2 +/- 5.9 kPa) during reaming of the medullary cavity. Insertion of 9-mm nails after the medullary cavity had been reamed to 10 mm produced an intramedullary pressure of 254 +/- 94 mm Hg (33.9 +/- 12.5 kPa) (p < 0.05). Fat extravasation in the unreamed group was recorded with a score of 2.9 +/- 0.4 for the Gurd test during nailing with 7-mm nails, whereas in the reamed group significantly more fat extravasation was noticed during the reaming procedures, with a score of 4.6 +/- 0.1. Liberation of fat during insertion of 9-mm nails after reaming was recorded with a score of 3.5 +/- 0.4. In both groups, a positive correlation of fat extravasation with the rise in intramedullary pressure was found (reamed group: r(s) = 0.868; unreamed group: r(s) = 0.698), resulting in significantly less liberation of bone marrow fat in the unreamed stabilized group than in the reamed control group (p < 0.05). The data indicate that fat embolization during nailing procedures after femoral osteotomy increases with increasing intramedullary pressure and occurs in a lesser degree in unreamed than in reamed intramedullary femoral shaft stabilization.     

Pulmonary fat embolism after reamed and unreamed nailing of femoral fractures

Background

To determine whether reamed or unreamed intramedullary nailing of femoral fractures results in higher incidence of pulmonary fat embolism, three different methods of intramedullary nailing were compared in sheep. To analyze the presence of bone marrow fat embolism in pulmonary arteries, histological evaluation was undertaken using a quantitative computer-assisted measurement system.

Methods

In this experimental model of 27 female Swiss alpine sheep, an osteotomy of the proximal femur was conducted in each animal. Then, the animals were divided into three groups according to the method of treatment: two different reamed intramedullary nailing techniques and an unreamed nailing technique were used.In the first group “ER” (experimental reamer; n = 9), the nail was inserted after reaming with an experimental reamer; in the second group “CR” (conventional reamer; n = 7), the intramedullary nail was inserted after reaming with the conventional AO-reamer. In the third group “UN” (unreamed; n = 8) unreamed nailing was performed. During the operation procedure intramedullary pressure was measured in the distal fragment.After sacrificing the animals, quantitative histological analyses of bone marrow fat embolism in pulmonary arteries were done using osmium tetroxide fixation and staining of the fat.

Results

The measurement of intramedullary pressure showed significantly lower values for reamed nailing than for the unreamed technique. The quantitative histological evaluation of lung vessels concerning bone marrow fat embolism revealed a statistically significant difference between reamed and unreamed insertion of the nail: 7.77% ± 6.93 (ER) and 6.66% ± 5.61 (CR) vs. 16.25% ± 10.05 (UN) (p < 0.05) of the assessed lung vessels were filled with fat emboli. However, no difference was found between the traditional and experimental reamer.

Conclusions

Intramedullary nailing after reaming is a safe procedure with low systemic embolisation when compared to the unreamed insertion of the nail.     

Prospective randomized study of reamed versus unreamed femoral intramedullary nailing: an assessment of procedures

OBJECTIVE: To determine whether the procedure of unreamed femoral nailing is simpler, faster, and safer than reamed femoral intramedullary nailing. DESIGN: Prospective randomized. SETTING/PARTICIPANTS: One hundred femoral shaft fractures without significant concomitant injuries admitted to an academic Level 1 urban trauma center. INTERVENTION: Stabilization of the femoral shaft fracture using a reamed or unreamed technique. OUTCOME MEASUREMENTS: The surgical time, estimated blood loss, fluoroscopy time, and perioperative complications were prospectively recorded. RESULTS: One hundred patients with 100 femoral shaft fractures were correctly prospectively randomized to the study. Thirty-seven patients received reamed and sixty-three patients received unreamed nails. All nails were interlocked proximally and distally. The average surgical time for the reamed nail group was 138 minutes and for unreamed nail group was 108 minutes (p = 0.012). The estimated blood loss for the reamed nail group was 278 milliliters and for the unreamed nail group 186 milliliters (p = 0.034). Reamed intramedullary nailing required an average of 4.72 minutes, whereas unreamed nailing required 4.29 minutes of fluoroscopy time. Seven perioperative complications occurred in the reamed nail group and eighteen in the unreamed nail group. Two patients in the unreamed group required an early secondary procedure. Iatrogenic comminution of the fracture site occurred during three reamed and six unreamed intramedullary nailings. Reaming of the canal was required before the successful placement of three nails in the unreamed group because of canal/nail diameter mismatch. CONCLUSIONS: Unreamed femoral intramedullary nailing involves fewer steps and is significantly faster with less intraoperative blood loss than reamed intramedullary nailing. The unreamed technique, however, was associated with a higher incidence of perioperative complications, although the difference was not statistically significant (p = 0.5).     

Similar central hemodynamics but increased postoperative oxygen consumption in unreamed versus reamed intramedullary nailing of femoral fractures

BACKGROUND: Patients undergoing intramedullary nailing of long bone fractures have pathologically altered pulmonary vascular tone, right heart strain, and transient impairment of pulmonary gas exchange. The purpose of this study was to examine the acute differences in cardiopulmonary variables between reamed and unreamed nailing techniques in 18 (9 + 9) healthy patients with unilateral femoral shaft fractures. METHODS: Intramedullary nailing was performed under general anesthesia within 12 hours after the trauma. For blood sampling, recording, and measurements, the patients were cannulated with radial artery and pulmonary artery catheters. Changes in central hemodynamics and oxygenation were studied pre-, peri-, and postoperatively for 16 to 20 hours. RESULTS: Abnormally high pulmonary shunting (23 +/- 12% in the reamed and 27 +/- 11% in the unreamed group) was observed before the operation. The trends of all variables were very similar in both groups except for the last phase in which the mixed venous oxygen saturation tended to be lower (65 +/- 8 vs. 70 +/- 5%) and the oxygen consumption index was higher (186 +/- 21 vs. 151 +/- 20 mL/min/m) in the unreamed group than in the reamed group (p < 0.05). The timepoints most strenuous to the heart were at the end of operation and in the recovery room. CONCLUSIONS: The unreamed intramedullary nailing technique does not offer any advantage in cardiopulmonary variables over the reamed technique. In both groups, there was considerable deviation in over 10 cardiopulmonary variables from normal reference values during the study. We suggest the use of invasive monitoring on patients with a long bone fracture and poor preoperative oxygenation or a history of cardiopulmonary or cardiac disease.     

Reamed versus nonreamed anterograde femoral nailing

OBJECTIVE: To compare reamed femoral nailing with unreamed femoral nailing. DESIGN: Prospective, randomized. SETTING: Two Level One trauma centers. PATIENTS: One hundred seventy patients with 172 femur fractures were randomized to an unreamed or reamed group. MAIN OOUTCOME MEASURES: Data included demographics, Injury Severity Score (ISS), operative time, blood loss, blood and fluid requirements, technical complications, time to callus formation, time to union, and complications. RESULTS: There was no statistical difference in operative time, transfusion requirements, or hypoxic episodes between the groups. Intraoperative blood loss was greater in the reamed group. The time to union was 80 +/- 35 days for the reamed group and 109 +/- 62 days for the unreamed group (p = 0.002). This difference was most dramatic in the distal femur, with union in the reamed group occurring in 80 days compared with 158 days in the unreamed group (p = 0.012). There were more technical complications and delayed unions in the unreamed group. CONCLUSIONS: There is no advantage to the routine use of nailing without reamed insertion. Fractures treated with reamed nails heal faster than those treated with unreamed nails, especially distal fractures.     

Kallusbildung nach aufgebohrter und unaufgebohrter Femurverriegelungsnagelung Eine experimentelle Studie

This was a prospective randomized baboon animal study, the study protocol was approved by the ethical committee according to the international guidelines for animal research projects. In 8 animals a midschaft femoral osteotomy was stabilized with reamed femoral interlocking nailing and in 8 animals by unreamed locked femoral nailing. Polychrome sequence bone labeling was done 5 weeks postop. with calcein-green, 8 weeks postop. with xylenol-orange and 10 weeks postop. with oxytetracycline. 10 weeks postop. the animals were sacrificed, the femurs explanted and planimetric and epifluorescence histomorphometric evaluation of serial transverse sections were done. In planimetric histomorphometric evaluation in unreamed femoral nailing a mean endostal callus formation was recorded with 28.0 +/- 9.9 mm2 per section and in reamed femoral nailing with 11.5 +/- 5.0 mm2 (p < 0.001). Periostal callus formation was recorded in the unreamed group with 238.7 +/- 87.1 mm2 per section and in the reamed group with 142.1 +/- 71.9 mm2 (p < 0.001). In epifluorescence histological evaluation endostal as well as periostal callus formation was more extensive and earlier after unreamed than reamed femoral nailing. Endostal callus formation was found in all animals after unreamed femoral nailing, and was present in 2 out of 8 specimen in the reamed group. Also 1 out of 8 animals in the reamed group developed a non-union. Unreamed femoral nailing with low diameter interlocking nails proved to be safe regarding bone healing in this experimental model with obvious advantages both in amount and time course of callus formation compared to reamed femoral nailing. Based on this results unreamed femoral nailing techniques can be recommended for femoral fractures.     

Fat embolism and related effects during reamed and unreamed intramedullary nailing in a pig model

OBJECTIVES: To determine whether reamed or unreamed femoral intramedullary nailing is more adverse to pulmonary function, the authors compared three populations of healthy pigs, analyzing the biochemical and hemodynamic effects related to fat embolism. Likewise, the authors histologically evaluated the presence of bone marrow fat embolism in lungs, heart, kidney, brain, and retina. DESIGN: Randomized, experimental model. SETTING: Laboratory. PARTICIPANTS: Twenty-five male Duroc Jersey adult healthy pigs divided in three groups. INTERVENTION: Reamed and unreamed intramedullary nailing. OUTCOME MEASUREMENTS: Biochemical, hemodinamical, and histologic analysis. METHODS: In the first group of ten pigs, a reamed nail was inserted; in the second group of ten specimens, the authors placed an unreamed nail; and in the third group of five animals (control), only the surgical approach was made without opening the medullary cavity. RESULTS: The authors did not find statistically significant differences in pulmonary function between the reamed and unreamed group in the hemodynamic, biochemical, and histopathologic parameters evaluated. The histologic analysis of the lung tissue revealed a statistically significant difference between the nailed groups and the control (P < 0.04). CONCLUSIONS: In this animal model, the results indicate that pulmonary changes and fat embolization during intramedullary nailing occur to the same degree in reamed and in unreamed femurs.     

扩髓与非扩髓型股骨髓内针术后免疫因子释放水平的研究

目的通过检测部分免疫介质的释放水平,探讨在应用髓内针治疗股骨干骨折术后早期对机体免疫功能的影响.方法选择股骨干闭合骨折患者59例,男55例,女4例,平均年龄32.1岁,按伤情分为轻伤组(n=43)和中度伤组(n=16),采取闭合复位带锁髓内针固定治疗.轻伤组扩髓23例、非扩髓23例,中度伤组扩髓7例、非扩髓6例,分别于术前24 h和术后1、24、48 h通过ELISA法检测患者血中TNF、IL-6、IL-8、IL-10的水平,通过蛋白分析测定CRP的水平;同时选取22例健康志愿者作为正常对照组.结果轻、中度创伤患者术后各炎症指标均较术前有所上升;IL-6、IL-8、IL-10在术后1 h呈上升趋势,术后24 h达到高峰,术后48 h 三种因子水平均开始下降,但尚未恢复正常;TNF、CRP术后1 h仍较术前有所下降,但在术后24 h均出现明显上升,到术后48 h再次回落;轻伤与中度伤组不同时段的免疫指标均与对照组有明显差异(P《0.05).不同伤情患者扩髓后各免疫指标均高于非扩髓者,但除中度伤组中IL-10在术后24 h有差异显著性意义(P=0.047)外,其它指标差异均无显著性意义(P》0.05). 2例患者术后出现SIRS,观察发现与非SIRS患者相比各项免疫指标并无显著差别.结论对于轻、中度创伤患者,髓内针会造成机体免疫介质再次大量释放,但经机体免疫调节后不会产生严重的影响;不同方式髓内针固定对术后早期机体的免疫系统的影响没有显著的差异,但以IL-10为代表的免疫抑制因子很可能随着伤情的加重在应用髓内针,尤其是扩髓型髓内针时出现短期内大量释放,从而加重机体的免疫抑制.     

Secondary effects of femoral instrumentation on pulmonary physiology in a standardised sheep model: what is the effect of lung contusion and reaming?

Intramedullary nailing is the treatment of choice for patients with femoral shaft fractures. However, there is an ongoing debate in multiple trauma patients with associated lung contusion when primary or secondary definitive stabilisation of the long bone fracture should be performed, as nailing is thought to play an important role in the pathogenesis of adult respiratory distress syndrome (ARDS). In a standardised sheep model, this study aimed to quantify the development of acute pulmonary endothelial changes, to assess the activation of polymorphonuclear leucocytes (PMNL) and to observe the effects on the coagulation system associated with the reamed nailing procedure. Furthermore, the effect of coexisting lung contusion in an experimental model was evaluated. The animals were randomly assigned to one of four different groups (6 animals/group). In control groups, only a sham operation (thoracotomy) was performed, whereas in study groups, lung contusion was induced prior to femoral stabilisation either by external fixation or reamed femoral nailing. Using bronchoalveolar lavage (BAL) pulmonary permeability changes were quantified and PMNL activation was assessed by chemiluminescence. Additionally PMNL diapedesis and interstitial lung oedema were determined by histological analysis. All animals were sacrificed 4 h after the start of the femoral instrumentation. Without an associated lung injury, instrumentation of the femoral canal with the reamed nailing technique induced a transient increase in pulmonary permeability. In the face of an induced lung contusion, reamed femoral nailing resulted in significant increases in PMNL activation, pulmonary permeability and interstitial lung oedema, compared with external fixation. Without pulmonary contusion, reaming of the femoral canal was associated with a transient increase in pulmonary permeability. This was exacerbated in the presence of lung contusion along with increased PMNL activation. External fixation did not provoke similar changes. The findings of this study support the view that reaming of the femoral canal should be avoided in polytrauma patients with severe chest trauma as it could act as an additional stimulus for adverse outcome. Temporary external fixation appears to be a safe method for fracture stabilisation until inflammatory and coagulatory disturbances after trauma have been normalized.     

髓内钉治疗股骨干骨折扩髓与不扩髓的比较研究

目的探讨非扩髓钉是否比扩髓钉操作简单、迅速、安全。方法用前瞻性随机研究方法将100例单纯股骨干骨折随机分为扩髓组与非扩髓组,比较二组的手术时间、失血量、手术中意外情况的发生。结果扩髓组37例手术时间138min,失血量278ml,6例术中发生意外情况。非扩髓组63例,手术时间108min(P=0．012),失血量186ml(P=0．034)。17例术中发生意外情况,2例需二次手术。结论非扩髓钉操作步骤少,手术时间及失血量少于扩髓组,但非扩髓组手术中意外情况发生较多,虽然统计学差异不显著。     

Healing of closed femoral shaft fractures treated with the AO unreamed femoral nail. A comparative study with the AO reamed femoral nail

Out of a hundred and seven closed femoral fractures, fifty-three were treated with the unreamed femoral nail and fifty-four with the reamed femoral nail. There were four delayed unions in the Unreamed Femoral Nail group (UFN) and three in the Reamed Femoral Nail group (RFN). There were no cases of infection or malunion. Implant failure was the cause of implant conversion in one patient of the UFN group. Healing time of the femoral fractures was 19.2 weeks in the UFN group and 19.6 weeks in the RFN group.Due to the significant decrease in operating time with the UFN (70 min) in comparison with the RFN (125 min) and the possible risk of posttraumatic pulmonary oedema (ARDS) with reaming techniques, the authors recommend the UFN for the treatment of acute closed femoral shaft fractures.     

股骨干骨折髓内针固定术后出现全身炎性反应综合征的回顾研究

目的回顾股骨干骨折髓内针固定扩髓与非扩髓患者术后发生全身炎性反应综合征（SIRS）情况,探讨髓内针固定与发生SIRS的关系。方法1997年4月至2005年4月股骨干骨折患者324例,按伤情分为轻度创伤组（n=179）和中度创伤组（n=145）。治疗采取闭合复位带锁髓内针固定,其中轻度创伤组64例、中度创伤组51例予以扩髓。分别记录每名患者入院后每日的体温、心率、呼吸频率,术后每6h记录相关数据,任何一项出现异常的患者即行血细胞分类计数,记录SIRS发生的情况。检测数据按不同伤情、扩髓与否进行分组,计算SIRS在各组中的发生率,并对之进行组内分组资料的卡方检验。结果术后早期出现SIRS者124例（发生率38．3％）,其中轻度创伤组61例（24例扩髓,37例未扩髓）,中度创伤组63例（27例扩髓,36例未扩髓）。124例中的119例经严密观测及常规术后治疗顺利恢复,5例则出现并发症。统计结果显示SIRS的发生率各组间差异无显著性。结论股骨干髓内针固定术本身会对创伤后的机体产生一定影响,导致发生SIRS;扩髓或非扩髓并不会对患者术后SIRS的发生与否产生明显的影响。     

Early patellofemoral osteoarthritis caused by an osteochondral defect after retrograde solid nailing of the femur in sheep

BACKGROUND: Retrograde femoral nailing (RFN) is an increasingly used technique for internal fixation of femoral fractures. Geometrically and empirically, the nail entry zone is close to the center of the femoral groove, causing concern about the development of patellofemoral osteoarthritis. METHODS: We studied the effect of opening the distal femur through the femoral groove on the development of osteoarthritis in sheep after retrograde reamed insertion of a solid titanium nail into the femoral canal. Knees were radiographically and macroscopically studied for the presence of osteophytes and signs of cartilage degeneration. Controls underwent the same procedure without opening the femoral groove. RESULTS: The study group showed time-dependent macroscopic and radiographic signs of osteoarthritis with predominant involvement of the patellofemoral joint. CONCLUSION: RFN can cause patellofemoral osteoarthritis. Care should be exercised to use RFN in isolated supracondylar or shaft fractures of the femur in healthy young adults.     

Interleukin-10 release and monocyte human leukocyte antigen-DR expression during femoral nailing

This study determined the effect of femoral nailing on the expression of monocyte Class II antigens and interleukin-10 release and sought to differentiate any differences in the release of these elements of immune reactivity in patients undergoing reamed and unreamed nailing. Thirty-two patients presenting with an acute femoral fracture were studied. In 15 patients, the femoral fracture was stabilized with a reamed technique and in 17 patients with an unreamed technique. Venous blood samples were taken at presentation, at anesthetic induction, immediately after nail insertion, and subsequently at 1, 4, and 24 hours and at 3, 5, and 7 days after surgery. Serum interleukin-10 was measured by an enzyme-linked immunosorbent assay, and monocyte human leukocyte antigen-DR expression was quantified by flow cytometry. Serum interleukin-10 release and human leukocyte antigen-DR expression on monocytes showed a clear response to the nailing procedure. The group of patients undergoing a reamed femoral nailing procedure showed significantly higher interleukin-10 release and a significant depression in the expression of human leukocyte antigen-DR on monocytes compared with those whose nail had been inserted unreamed. One patient in the reamed femoral nailing group died of adult respiratory distress syndrome 3 days after injury. Reamed intramedullary nailing appears to be associated with greater impairment of immune reactivity than is the unreamed nailing technique.     

Retrospective analysis of healing problems after reamed and unreamed nailing of femoral shaft fractures

168 fractures of the femoral shaft treated by intramedullary nailing were analyzed retrospectively. From 1986-1992 116 fractures had been treated with the reamed AO universal nail (RFN) and from 1993-1996 52 fractures with the AO unreamed femoral nail (UFN). In 24% of the RFN-group and in 2% of the UFN-group (p < 0.0001) open reduction of the fracture had been necessary. The time to radiological consolidation was similar in both groups (18.1 weeks +/- 6.1 vs. 18.3 weeks +/- 5.7, [mean +/- SD]). Delayed unions were less frequent in the RFN-group than in the UFN-group (3% vs. 13%, p = 0.01). Non-unions occurred in the RFN-group in 4%, in the UFN-group in 8%, the difference is not statistically significant (p = 0.46). Fractures with impaired consolidation (delayed-unions and non-unions) in the RFN group were distributed randomly along the femoral diaphysis, whereas all 11 fractures with retarded healing in the UFN group were short transverse or oblique fractures localized immediately distal to the femoral isthmus. We believe that there is mainly a mechanical reason for this phenomen, in addition to fracture type and fracture localization the (insufficient) length of the unreamed nails might have impaired stability further. The different factors should be investigated in larger series. As a consequence we now treat transverse and short oblique fractures of diaphyseal femoral fractures distal to the femoral isthmus with a RFN whereas in other types and localizations of diaphyseal femoral fractures we continue to use the UFN with special attention to maximal nail diameter and length.     

Reaming during anterograde femoral nailing: is it worth it?

A systematic review was performed to assess the relative merits of reamed and unreamed antegrade femoral nailing. To be included, a study had to be prospective, randomised or pseudorandomised, comparing reamed and unreamed antegrade femoral nailing in adults. Where more than one study from the same institution was available, only the study with longest follow-up was included. A literature search found 2044 possible articles. Of these, eight studies compared reamed and unreamed femoral nailing. The methodology of these articles was independently assessed by all the three authors. Five studies met the inclusion criteria. Each outcome measure tested was assessed for heterogeneity. If significant heterogeneity was present, the data were not combined. If there was no significant heterogeneity, a combined odds ratio or weighted mean difference was calculated using a fixed effects model, and a Z-test was performed to test the overall effect. Six hundred and forty-seven femoral fractures (315 reamed; 332 unreamed) were entered into the included studies. Unreamed nailing was quicker and associated with significantly less blood loss (P < 0.00001). Reaming significantly reduced the time to union (P = 0.00001), non-union (P = 0.002), delayed union (P = 0.005), technical problems (P = 0.01) and reoperation rate (P = 0.001). The use of reamed femoral nails gives significant advantages over unreamed femoral nails.     

Wissenschaftliche Grundlagen der aufgebohrten und unaufgebohrten Marknagelung

A comparative investigation of differences in new bone formation and cortical remodelling after reamed and unreamed nailing was carried out in a standardized animal model. An oblique osteotomy of the tibia was created in 19 sheep, followed by intramedullary nailing. The medullary cavity was reamed ?in 10 of the animals, while in 9 sheep unreamed nailing was performed. After an observation period of 10 weeks, microradiographical assessment indicated more intensive bone regeneration and better bridging of the osteotomy in the animals with unreamed nailing. In addition, fewer aseptic bone sequestra were identified in the “unreamed” group. Morphometric measurements of the specimens by fluorescence ?microscopy showed a significantly earlier and more pronounced interfragmentary and periosteal regeneration of bone, and significantly smaller central cortical zones without any remodelling. The results are of particular clinical relevance to the stabilization of fractures with severe open or closed soft tissue injury. Unreamed nailing procedures do less damage to the bone than reamed procedures. The former are less invasive and lead to earlier and more intensive bone regeneration. Not only these biological advantages, but also the lower mechanical stability and strength associated with unreamed nailing should be taken into account when assessing whether reamed or unreamed nailing is indicated.