Analysis of implantation-induced nail deformation and roentgen morphometric studies as the principle for an aiming device for distal interlocking nailing without roentgen image intensification

While working to develop a distal locking device, we analyzed distal nail position with reference to nail deformation and a radiographic-morphometric investigation. The amount and the direction of implant deformation in unslotted stainless steel unreamed tibial nails (Synthes) were analyzed. Measurement of implant deformation (3 translations, 3 angles) in the center of the distal transverse locking hole was performed with a 3D magnetic motion tracker system before and after nail insertion. Unreamed tibial nails (diameter 8 mm, n = 10; diameter 9 mm, n = 10) were inserted in paired human cadaver tibiae. The results showed lateral translations of -4.5 +/- 3.5 mm (mean and standard deviation, range 14.3 mm) and dorsal translations of -7.8 +/- 5.8 mm (mean and standard deviation, range 19.2 mm). Rotational deformations around the longitudinal axis of the nail were 0.3 +/- 0.7 degree (mean and standard deviation, range 2.4 degrees). The results showed, that a simple aiming arm, mounted on the proximal nail end, alone or even in combination with a large working channel (e.g. 10 mm in diameter), was not adequate to the aiming process. A radiographic-morphometric analysis was subsequently performed in 40 tibiae after experimental (n = 20) or clinical (n = 20) implantation of nails 8 mm and 9 mm in diameter. These measurements showed a relatively constant distance between the upper distal transverse hole and the anterior aspect of the tibia (average 12.3 mm and only a narrow range (7.6 mm). These data were the basis for the development of an aiming technique that exploits the relatively constant distance between the distal nail hole and the anterior aspect of the tibia. This aiming device is set at a distance of 12.3 mm from the anterior cortex, and the fine tuning is finally resolved by the use of a "working channel' 10 mm in diameter.     

A comparison of a fluoroscopy-free mechanical targeting system and a free-hand technic for the placement of distal interlocking screws of tibial nails

Recently, radiation-independent aiming devices for the tibia which compensate for insertion-related implant deformation have been developed, but the benefits of such systems have not been determined. This study prospectively evaluated the duration of the nailing procedure, the length of radiation time, and the accuracy of interlocking screw placement with a radiation-independent distal aiming system and the free-hand technique. In an oblique cadaveric tibial fracture, a surgeon inexperienced with either technique performed a statically locked intramedullary nailing. For the aiming system and free-hand technique respectively, the total operation time was 25.4 +/- 11.3 vs 30.9 +/- 14.3 min (P = 0.029), the distal locking time was 16.7 +/- 8.6 vs 21.9 +/- 10.5 min (P = 0.004), the total fluoroscopy time was 9 +/- 5 vs 93 +/- 34 s (P < 0.0001), the distal locking fluoroscopy time was 0 versus 88 +/- 33 s (P < 0.0001), and the screw destruction was -0.7 +/- 5.2 vs 26.8 +/- 31.6 microns (P = 0.001). The failure rate was 1.6% (1 of 60 screws) in both groups. These results suggest that aiming devices can eliminate the need for radiation during distal interlocking screw placement.     

Biomechanics of rigid tibial nail insertion sites

The use of a very proximal insertion site for rigid intramedullary nailing was evaluated in a biomechanical study. The purpose of this study was to compare the bursting strains generated in a proximal tibia fracture fragment during rigid nailing, using the recommended insertion sites versus a more proximal site just anterior to the tibial plateau in the midline. Proximal one-third tibia fractures were created in 12 pairs of fresh cadaver specimens. Strain gauges were applied to the medial and lateral cortices of the proximal fragments. Lottes nails, Grosse-Kempf nails, and unreamed Russell-Taylor nails were inserted in four successive pairs of specimens. In each pair, one side used the recommended starting point, and the other side used the proximal insertion site. The strain was recorded at successive 2- to 4-cm depth intervals during nail insertion. In the Lottes group, much larger bursting strains were generated in the lateral cortex when using a distal starting point (P < 0.05). In the unreamed Russell-Taylor group, the anteromedial surface strains were significantly increased using a distal starting point (P < 0.05). The Grosse-Kempf group showed no significant difference in strains associated with any insertion point during tibial intramedullary nailing.     

Interlocking nailing for fractures of the femur and tibia

In 132 patients, fractures of the lower limb (71 femoral and 61 tibial fractures) were treated using interlocking nailing (ILN) according to Grosse and Kempf during the period 1986-1989. Of these, 118 were followed up for a median of 19 months (range 9-32 months). Inpatient stay averaged 9 days regardless of the fracture. Consolidation was achieved in approximately 3 or 4 months from the operation in tibial and femoral fractures, respectively. Tibial fractures were technically more demanding than femoral ones, and their average operating time was significantly longer (73 min versus 51 min). Only one patient had a malunion in malrotation. The most serious complication was in a closed upper tibial fracture with traumatic rupture of the popliteal artery. Although the nailing was technically successful, an above-knee amputation had to be carried out. In only one case did the nail fail, and tibial plating had to be performed. Given the present degree of expertise, ILN for fractures of the long bones of the lower limb is a safe and relatively easy procedure to perform.     

Minimally invasive method for treatment of supra-diacondylar femoral fractures

The "gold standard" treatment modality for extra-articular and combined intra-, extra-articular fracture of the distal femur is the condylar blade plate (CP). Large exposure of the distal femur with unavoidable iatrogenic trauma to the soft tissue surrounding the fracture site and perhaps the lack of stiffness of the eccentric lateral cortical location of the CP has been suggested to play a role in the high rate of infections and pseudarthrosis reported in the literature. In an effort to overcome some of the difficulties with the condylar blade plate and to reduce complications, an unreamed, titanium, solid nail, locked proximally with two locking screws and distally with a screw and twisted blade was developed (DFN). The nail was designed for minimal invasive reduction through a small median parapatellar arthrotomy of the articular fracture (percutaneous screw) and of the supracondylar fracture. The DFN is a modular system sharing many components and almost all instrumentation with the AO-UFN and it is expected that the nail is much better in axial stiffness and strength than the condylar blade plate. The treatment of supracondylar femoral fractures should be improved by providing early weight bearing and accelerated fracture healing with a reduced incidence of delayed unions and infections.     

Use of a CEPH meiotic breakpoint panel to refine the locus of limb-girdle muscular dystrophy type 1A (LGMD1A) to a 2-Mb interval on 5q31

BACKGROUND: Cortical reaming and intramedullary nail insertion injure the medullary vascular system. Little attention has been directed toward quantitative assessment of bone injury and repair after locked intramedullary nailing of long-bone fractures with and without reaming. The effects of reamed versus unreamed locked intramedullary nailing on cortical porosity and new bone formation were compared in a sheep fractured tibia model. METHODS: After creation of a standardized spiral fracture by three-point bending with torsion, each tibia was stabilized by insertion of a locked intramedullary nail. Ten sheep were randomized into two groups, one that had reaming before nail insertion and one that did not. Fluorochromes were given 2 weeks (xylenol orange), 6 weeks (calcein green), and 12 weeks (tetracycline) postoperatively. All animals were killed at 12 weeks postoperatively. Cortical porosity and new bone formation were determined for the proximal diaphysis, fracture site, and distal diaphysis. RESULTS: Overall cortical porosity was greater with reamed nails than with unreamed nails (p = 0.02). Porosity in the inner cortex (18.3% (reamed) vs. 14.3% (unreamed); p = 0.09) and outer cortex (16.8% (reamed) vs. 12.2% (unreamed); p = 0.04) was greater in the reamed group. With reamed nails only, there was less new bone formation at 2 (p = 0.04) and 12 (p = 0.05) weeks in the inner cortex compared with the central cortex and outer cortex. Overall, there was no difference between reamed and unreamed nails in the amount of new bone formation at 2, 6, or 12 weeks. CONCLUSIONS: This study demonstrates that greater injury or overall cortical porosity is associated with reamed nail insertion. There is no difference, however, between the amount of new bone formation after reamed and unreamed nail insertion. Nail insertion without reaming may be initially advantageous when tibial cortical vascularity is compromised, by limiting further injury to cortical bone. This may be important with open tibial fractures in which there is a significant risk of infection after injury. Between 2 and 12 weeks after injury, neither reamed nor unreamed nail insertion seems to have a significant advantage with respect to the amount of new bone formation that occurs.     

Initial results with the unreamed AO tibial nail

It is generally accepted that intramedullary nailing in combination with reaming should be avoided in treating open fractures. However, the use of an unreamed, solid nail combined with interlocking also allows stabilization of open and complex fractures. 20 tibia fractures (65% open, 45% complex fractures) have been treated by the AO unreamed tibial nail (UTN), 12 (5 of them open fractures) by direct nailing and 8 after initial stabilization by an external fixator. In our series no intraoperative complications, no soft-tissue healing problems and no infections occurred. Thus, treatment of both open and comminuted fractures by UTN appears to be safe and generally needs no secondary stabilization.     

Retrograde nailing of humerus shaft fractures with the unreamed humerus nail. An international multicenter study

Combined with the new unreamed humeral nail (UHN) (Synthes), the retrograde approach to the endomedullary canal of the humeral shaft promises careful reduction and fixation of humeral shaft fractures. This prospective multicenter study reports and analyses 102 retrograde nailings with the UHN and their operative procedures. Seven patients with pathological fractures have died meanwhile, but 75 patients could be followed up until bone healing. Seventy-three fresh humeral shaft fractures, 12 pseudarthrosis, 3 refractures and 14 pathological fractures have been treated with the UHN. In 98 cases (96.1%) the surgeon estimated fracture stability well enough to initiate immediate postoperative elbow and shoulder mobilization. The difficulties involved with free-hand interlocking proximally at the nail tip in 5.9%, fissure or avulsion at the insertion point in 3.9% and radial nerve palsy also in 3.9% of the cases were the most important intraoperative complications. In all 75 patients followed up, bone healing occurred, but five fractures (6.7%) needed more than 8 months connected with a second operative procedure. In one case spongious bone transplantation and new locking bolts had been performed. In three cases a special compression device has been used, whereas in one case also a new nail and in the second spongious bone transplantation had been added. In the fifth case plate osteosynthesis had been performed. At the end of treatment 89.4% of the patients had excellent shoulder function and 88.0% excellent elbow function. Once the indication for surgery is established, the UHN can be considered a reliable and safe implant for stabilizing humeral shaft fractures.     

New developments in stabilization of dia- and metaphyseal fractures of long tubular bones

Nail, plate and external fixator are since decades the most frequently and stabilizers for the surgical treatment of dia- and metaphyseal fractures. These elements are still present today. However, there were important changes in recent years. Together with better knowledge and understanding of fracture healing, fracture biology, implant metallurgy and mechanics and a more and more specified application of these techniques, this resulted in improved possibilities for the treatment of injured patients. Beside an overview about the current discussion of unreamed and reamed nail insertion new trends, techniques and nails are presented for the different long bones (retrograde nails, spiral blade, flex-nail humerus and a distal aiming device (DAD) for interlocking screws). In addition, new approach techniques for nailing (stab incision) and minimally invasive percutaneous plate osteosynthesis (MIPO) for metaphyseal fractures of the proximal and distal femur and proximal tibia are described including the necessary techniques for control of axes and rotation.     

Advantages of the unreamed tibial nail in comparison with external fixator in treatment of grade 3 B open tibial shaft fractures

Between 1987 and 1993, 41 grade 3B open tibial shaft fractures were treated with the unreamed tibial nail (URTN n = 22) or an external fixator (FIX n = 19). The method of treatment was left to the choice of the operating surgeon. Three below the knee amputations were performed, three patients died, and three were lost to follow-up. In all, 32 patients were followed up to union or at least for 1 year. There were no significant statistical differences between the two groups (P < 0.2, chi-squared, t-test) with respect to fracture type, fracture location, age, gender or accompanying injuries. The URTN group showed significantly better results regarding time to full weight-bearing (URTN 11 +/- 4 weeks; FIX 20 +/- 11 weeks, P < 0.01 M-W) Mann-Whitney Test, number of reoperations (URTN 1.04; FIX 2.89; P < 0.01 M-W), isolated bone grafting (URTN 3/22; FIX 8/19; P < 0.05 chi-squared), and average Karlstr?m and Olerud score (URTN 30 +/- 4; FIX 26 +/- 5; P < 0.05 M-W). In all, 15/17 URTN patients and only 6/15 FIX patients achieved unlimited walking distance (P < 0.01 M-W). Time to bony union, infection, and nonunion were not significantly different between groups.     

Pyridostigmine bromide and Gulf War syndrome

A problem arose when the reamed tibia nail was replaced by a massive unreamed tibia nail. Of the nail fractures, it is difficult to remove the distal fragment from the medullary cavity. It may also happen that the connecting screw between the insertion handle and the nail breaks off at the edge of the implant, which complicates removal of the nail. The authors have developed a technique for removing the implant without having to saw a fissure in the marrow. A concave instrument is slid over the part of the nail left behind after which the two are connected by means of a K wire. This method has been successfully applied in two patients.     

Stabilization procedures in large soft-tissue and bone defects

When stabilizing fractures with large soft tissue and bone defects, the primary concern is to avoid additional vascularization damage. Therefore, external fixation is still the standard method. In metaphysical fractures, joint transfixation should be avoided if possible. Concerning closed comminuted fractures of femoral and tibial shaft fractures, interlocking nailing shows the lowest complication rate. The introduction of unreamed nailing of open fractures shows the same low infection rate as external fixation, so it can be considered an alternative method. Early plate fixation is applied for fractures of the upper extremities as well as the proximal and distal femur, if secure covering with vital tissue can be provided. As this is not guaranteed in the case of the tibial shaft, plate fixation remains the absolute last resort. Concerning distal and proximal fractures of the tibial pylon and tibia head, plate fixation is very often applied for definitive stabilization. However, the secondary application represents a considerably lower infection and fracture-healing risk.     

Leg tissue perfusion in simple tibial shaft fractures treated with unreamed and reamed nailing

BACKGROUND: To compare the effects of unreamed and reamed intramedullary nailing on tibialis posterior, dorsalis pedis, and sum (tibialis posterior plus dorsalis pedis) distal arterial peak pulses. Additionally, leg skin temperature and transcutaneous oxygen tension were measured in patients with low energy, closed tibial shaft fractures. METHODS: The patients were randomized to unreamed and reamed groups, and intramedullary nailing without or with reaming was performed under spinal anesthesia. The measurements were carried out before the operation and on 5 postoperative days. RESULTS: In the unreamed group, the only significant difference between contralateral and nailed legs was in raised leg skin temperature (p = 0.0001). In the reamed group, tibialis posterior distal arterial peak pulses and transcutaneous oxygen tension remained at a significantly lower level and leg skin temperature at a significantly higher level, respectively, in the nailed legs after the operation when compared with contralateral legs (p = 0.0026, p = 0.0001, and p = 0.0001, respectively). There were no statistical differences between preoperative and postoperative values in the measured parameters in both groups. Additionally, there were no intergroup changes in the measured parameters in the injured legs. CONCLUSION: The present study suggests that altered distal arterial pulsations, decreased transcutaneous oxymetry values, and thermal reaction are not due to differences in nailing method but caused by a manifestation of the trauma mechanism of the tibial shaft fracture. The potentially negative effects of reaming to soft tissue perfusion parameters could not be established.     

Interface pressure measurements of support surfaces with subjects in the supine and 45-degree Fowler positions

The results of treatment of 35 intraarticular distal fractures of the femur are presented. Treatment was performed in 8 cases with a condylar plate, in 8 cases with dynamic compression screw (DCS), in 2 cases with two plates, in 9 cases with screws only, and eight times the fracture was treated with a combination of lag screws and locking nail. Examination took place at an average of 45.5 months after the accident. 19 patients had an isolated fracture, 8 patients one accidental injury and 8 patients had more than one fracture or were polytraumatised. In 75% of the patients treatment lasted for between day 1 and 5. We found 17.1% open fractures and had to face infections in 5.7% (two cases). Bone healing occurred in all fractures, the reported infections could be overcome by early revision and the use of gentamycin-PMMA beds. It is remarkable that locking nails were successfully used in 8 cases of fractures with intraarticular component of the distal femur.     

Compartment pressure monitoring during intramedullary fixation of tibial fractures

Twenty-six legs in 25 patients were monitored prospectively for compartment pressures during intramedullary nailing of open and closed tibial shaft fractures. Twenty-three patients were treated within 24 hours of admission. Twenty-three unreamed and three reamed intramedullary rods were utilized. Compartment pressures were measured initially, following fracture reduction, and during reaming. Pressures were also measured at the completion of nailing with the ankle dorsiflexed and at rest (plantar flexed) to determine positional effects on compartment pressures. Nine fractures (35%) were found to have persistently elevated pressures (> 40 mm Hg) and underwent immediate four-compartment fasciotomy. The remaining group of 17 fractures (65%) was monitored throughout the intraoperative period. No patient monitored intraoperatively developed postoperative compartment syndrome.     

Normalization of cognitive and functional assessment instruments for dementia (NORMACODEM) (I): objectives, content and population]

We give an account of the first Austrian clinical results of a prospective study dealing with fractures of the femoral shaft treated with the UFN-system, the intraoperative handling especially considering the intra- and postoperative complications. The UFN-system combines the advantages of numerous proximal interlocking options for the treatment of nearly all femoral fracture patterns with that of the unreamed nailing (biological osteosynthesis, primary stability with individual after-treatment, high patient's comfort and early mobilisation). Within two years (VII/94-VII/96) sixty closed and four second degree open fractures were stabilized with the unreamed femoral nail. In twelve cases we used the spiral blade interlocking technique. Five times we changed from external fixator to the UFN. The fractures were classified according to the AO-classification. In 64 implanted UFN there occurred twelve intraoperative and four postoperative complications. In five cases reoperation was necessary. Failings in the operative technique, numerous different experienced surgeons and a deficient after_treatment led to our pitfalls.     

The retrograde intramedullary supracondylar nail: an alternative in the treatment of distal femoral fractures in the elderly?

To find out whether retrograde nailing of distal femoral fractures is beneficial for the aged patient, we performed a prospective study of consecutive patients 65 years or older with distal femoral fracture treated with a retrograde femoral nail between 1 March 1993 and 30 April 1996 in our department. In total, 26 patients with unilateral distal femoral fractures had been treated in our department, and 24 patients had been followed up for more than 12 months. All fractures had healed. Six patients did not walk before the injury. According to the Neerscore we counted 10/18 excellent results (> or = 85 points), 6/18 good results (> or = 70 points), 2/18 fair results (> or = 55 points) and no failures (< 55 points). Retrograde intramedullary nailing makes a biological osteosynthesis of distal femoral fractures possible. Even in our aged patients good functional results could be obtained. Poor hold of the distal interlocking screws and difficult proximal locking are the two major technical problems encountered with this implant. Early weight-bearing is not advisable.     

Intramedullary pressure and bone marrow fat intravasation in unreamed femoral nailing

OBJECTIVE: To investigate whether intramedullary pressure and bone marrow fat embolization are different in unreamed compared with conventional reamed femoral nailing. The null hypothesis is that there is no difference between the two techniques. DESIGN: A prospective consecutive nonrandomized clinical trial. METHODS: Intramedullary pressure was measured in the distal femoral fracture fragment at the supracondylar region. Bone marrow fat intravasation was measured by means of the modified Gurd-test. Monitoring was carried out in 31 unreamed and eight reamed intramedullary femoral nailing procedures. RESULTS: Intramedullary pressure increased in the unreamed group to 82 +/- 11 mm Hg during the insertion of 9-mm and 10-mm nails and in the reamed group to 396 +/- 85 mm Hg during reaming of the medullary cavity. Insertion of nails after reaming led to an increase in intramedullary pressure of 79 +/- 13 mm Hg. A positive correlation between fat intravasation and intramedullary pressure was found in each group (rs = 0.73), resulting in less liberation of bone marrow fat in the unreamed group than in the reamed group. CONCLUSIONS: Intramedullary pressure increased significantly in the reamed more than in the unreamed group. Bone marrow fat intravasation depended on the rise in intramedullary pressure, and occurred less frequently in unreamed than in reamed intramedullary femoral fracture stabilization.     

Nonreamed locking intramedullary nailing for open fractures of the tibia

The use of nonreamed interlocking tibial nails in the management of open fractures of the tibial shaft has gained wide acceptance. This technique has been reported to have reproducible good results with a low incidence of complications in Type I, Type II, and Type IIIA open tibial shaft fractures. The use of nonreamed nails in Type IIIB fractures continues to be a source of controversy. The treatment of 72 open fractures of the tibial shaft with nonreamed interlocking intramedullary nailing is detailed. There were 27 Type I, 22 Type II, 11 Type IIIA, and 12 Type IIIB open tibial shaft fractures. There were three (4.2%) deep infections; one Type II, one Type IIIA, and one Type IIIB. Forty-nine fractures (68%) united by 6 months, all fractures had united by 12 months. The use of nonreamed locking intramedullary nailing in Types I, II, IIIA, and IIIB open fractures of the tibial shaft is supported.     

Reamed interlocking intramedullary nailing of open fractures of the tibia

One hundred twelve open tibial fractures were treated by reamed interlocking nailing in 108 patients. There were 31 (28%) Grade I fractures, 38 (34%) Grade II, 23 Grade IIIA (21%), and 20 (18%) Grade IIIB fractures. Early amputation was performed in 2 (10%) Grade IIIB fractures for severe crushing injuries. Compartment syndrome complicated 8 (7%) fractures. Mean time to union was 29 weeks for Grade I fractures, 32 weeks for Grade II, 34 weeks for Grade IIIA, and 39 weeks for Grade IIIB. Nonunion complicated 9 (8%) fractures: 1 (3%) Grade I fracture, 2 (5%) Grade II fractures, 3 (13%) Grade IIIA fractures, and 3 (17%) Grade IIIB fractures. Deep infection complicated 4 Grade II fractures (10%) and 2 (11%) Grade IIIB fractures. Reamed locking intramedullary nailing is a safe and effective technique for management of open tibial fractures.