Removal of a broken solid femoral nail: a simple push-out technique. A case report.
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Adult↗
Biomedical subjects
C Krettek
Publications and source records attributed to C Krettek.
[Fracture management in polytrauma. Timing and tactics].
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External Fixators↗
Superior results of tibial rodding versus external fixation in grade 3B fractures.
From 1987 to 1993, 41 Grade 3B open tibial shaft fractures were treated with the unreamed tibial nail or an external fixator. The method of treatment was left to the choice of the operating surgeon. Three below knee amputations were performed; three patients died; and three were lost to followup. Thirty-two patients were observed until union or for at least 1 year. There were no significant statistical differences between the two groups with respect to fracture type, fracture location, age, gender, or accompanying injuries. The unreamed tibial nail group showed significantly better results regarding time to full weightbearing, number of reoperations, isolated bone grafting, walking range, and average Karlström and Olerud score. Time to bony union, infection, and nonunion were not significantly different between the groups.
Adult↗
[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.
Bone Nails↗
[Biomechanics of femoral interlocking nails at the bone-implant transition].
Today there is a variety of different interlocking intramedullary nail designs available for the femur-each designed with a different approach to achieve stability for fracture fixation. We compared different nail types in the bone-implant complex (BIC) of four unreamed solid nails and a slotted, reamed nail to see if there are major differences in stiffness for axial load, bending and torsion. We simulated comminuted mid-shaft fractures by a 2 cm defect osteotomy in paired human cadaver femora. Each bone was tested intact in a Universal testing machine. The results were recorded, osteotomy and osteosynthesis were performed, and the BIC was tested. Relative stiffness was calculated for each individual bone. For P-values less than 0.01 ('least significance difference test') the difference between groups was considered to be significant. In torque testing the unslotted solid nails showed significantly more stiffness (0.6-1.8 Nm/degree) compared to the slotted nail (0.2 Nm/degree). Compared to intact bone (6.9 Nm/degree), both groups of nails were significantly less stiff (relative stiffness 2-20%). In axial load and bending testing, the large-diameter unreamed nail showed greater higher stiffness (32-68%). This study shows that stiffness of the BIC in interlocking femoral nails is more dependent on nail profile than on the press-fit of nails in the medullary canal. For torque stiffness the absence of a slot is of special importance. According to our study, all of the unslotted nails tested give adequate stability for fracture fixation.
Adult↗
Fractures of the odontoid process in small children: biomechanical analysis and report of three cases.
Odontoid "fractures" in young children typically involve the cartilaginous plate (synchondrosis) that separates the odontoid process from the body of the axis; 58 cases have been described in the literature. We report two cases in which 2-year-old children were involved as backseat passengers in head-on motor vehicle accidents, both were restrained by four-point child's seat harnesses. A biomechanical investigation was carried out using simulation in a real car crash test with a child dummy. This revealed that head-on collisions with a speed absorption of at least 40 km/h are the typical mechanism of injury in children under the age of 3 years involved in motor vehicle accidents. Shearing force is all that is necessary to explain the dens fracture. Both children were immediately symptomatic, and the diagnosis was obvious on radiographs. Neither child had neurological deficit, which correlates well with the literature, where neurological injuries were found only in conjunction with head injuries. After closed reduction, both cases were initially treated conservatively with halo and plaster vest for 12 weeks. In one case, in which the anterior dislocation was less than the diameter of the odontoid shaft, eventless healing occurred. In our second case, despite an anatomic reduction, the odontoid fracture failed to unite. After a temporary posterior fixation of C1/C2 we reamed the synchondrosis from anterior and performed autogenous bone grafting. The posterior fixation wire was removed after 5 months. In contrast to the literature, we do not recommend a permanent posterior fusion of C1/C2. Our two young patients were both followed-up for more than 3 years. Clinical and radiological examination at final follow-up was normal with no signs of atypical growth of the odontoid. In cases of major dislocation with greater instability we recommend primary open reduction and osteosynthesis with appropriate implants. This was done in a third case: a 1 1/2-year-old boy who fell down the stairs and sustained a head injury and an unstable lesion of the odontoid with subtotal paraplegia. The odontoid was fixed with two screws.
Biomechanical Phenomena↗
[Complex trauma of the knee joint. Diagnosis--management--therapeutic principles].
The complex nature of combined fractures and soft tissue injuries of the distal femur and proximal tibia needs special attention and specific management. Distal femoral and proximal tibial fractures in young patients are usually caused by high-energy trauma. They are complicated by a high rate of systemic and local injuries to cartilage, ligaments and skin. This small but important group with severe injuries needs a detailed treatment algorithm, because despite the treating surgeon's skill, enthusiasm and wishful thinking, these injuries frequently lead to unsatisfactory results. The combination of distal femoral fractures and proximal tibial fractures was defined as complex knee injury type 1; the combination of distal femoral fractures or proximal tibial fractures with second or third degree open or closed soft-tissue injury was defined as complex knee injury type 2; knee dislocations were defined as complex knee injury type 3. A decision-making scheme is presented specifically addressing timing and treatment modalities. Out of 116 type 1 and 2 complex knee injuries, 8 had a deep infection, in 6 cases an amputation was carried out and in 4 cases a knee arthrodesis was performed. In 81 isolated distal femoral fractures, only 4 had a deep infection, none needed amputation, and in only 1 case did a knee arthrodesis have to be performed. The average Neer Score in 90 followed-up complex knee injuries, types 1 and 2, was 76.5 +/- 13.5 compared with 82.8 +/- 10 (out of 54 isolated distal femoral fractures). Out of 37 cases with knee dislocation, 22 (60%) had an poor result according to the Lysholm Score (average Lysholm Score 60.7 +/- 28).
External Fixators↗
[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.
Biomechanical Phenomena↗
[Elastic plate osteosynthesis].
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Biomechanical Phenomena↗
Unreamed intramedullary nailing of femoral shaft fractures: operative technique and early clinical experience with the standard locking option.
Nailing techniques have changed in recent years in ways which are not just limited to omitting the reaming process. These changes concern positioning patients, techniques of reduction and selecting implants. Techniques of approach and exposure have been modified to new, less-invasive procedures to fulfill technical, functional and cosmetic requirements. In addition, techniques have been developed to avoid fragment diastasis, rotational and sagittal malalignment, and leg-length discrepancy. Finally, simple algorithms have been elaborated for the management of specific fracture patterns (bilateral shaft fractures, ipsilateral tibial fractures or associated femoral neck fractures) and to determine the number and location of locking bolts. We developed these algorithms, techniques and procedures in a series of 133 femoral shafts, which were stabilized with the AO unreamed femoral nail (URFN) in a prospective study between 1991 and 1994. Of these, the first 57 cases with a mean follow-up of 17.9 months (range, 5-44) after injury were reviewed. Fractures were classified according to Müller's 1990 system: 12 type A, 29 type B and 16 type C. Closed soft-tissue injuries were classified by our classification of 1982: 17 type C 0/I, 42 type C II. Of 15 open fractures, six were OI, six OII, two OIIIA and one was OIIIB by Gustilo's classification of 1984. The major complications were two broken locking bolts, one nail breaking after 9 weeks, one case of osteitis and one of intra-operative lung embolism.
Adolescent↗
Biomechanical study of nine different tibia locking nails.
We compared different nail types within the Bone/Implant-Complex to look for differences in stiffness for axial load, bending and torsion of the System. We simulated comminuted mid shaft fractures by a 2-cm defect osteotomy in paired human cadaver tibiae. We fixed tibiae with one of nine different interlocking nails [AO Unreamed Tibial Nail 9 mm (UTN9), AO Unreamed Tibial Nail 8 mm (UTN8), Russell & Taylor Delta Tibial Nail 9 mm (RTD), Russell & Taylor Reconstruction Tibial Nail 11 mm (RTR), Brooker & Wills Tibial Nail 11 mm (B&W), Grosse & Kempf Tibial Nail 11 mm (G&K), AO Universal Tibial Nail 11 mm (AOU), Klemm & Schellmann Tibial Nail 11 mm (K&S), and Börner & Mattheck Tibial Nail 11 mm (B-M)] according to the manufacturer's recommendations. In torque testing the unslotted nails (UTN9, UTN8, RTD, RTR, B&W) showed significantly higher stiffness compared to the slotted nails (G&K, AOU, K&S, B-M). Compared to intact bone, both groups of nails were significantly less stiff. In axial load testing large diameter nails interlocked by large diameter interlocking bolts (G&K, K&S, B-M) showed significantly higher stiffness. For A-P bending no significant differences between implants were found, but isolated bones showed significantly higher A-P bending stiffness. In varus-valgus bending large diameter nails (RTR, G&K, K&S, B-M) showed significantly higher bending stiffness compared to low diameter (UTN8, B&W) implants.
Adult↗
Fatal pulmonary embolization after reaming of the femoral medullary cavity in sclerosing osteomyelitis: a case report.
Reaming of the medullary may be used in cases of sclerosing osteomyelitis (type Garré), refractory to other methods. We report a case of fatal intraoperative complication related to this procedure. An otherwise healthy young patient died during reaming using a machine-driven reamer of the femoral medullary canal due to pulmonary bone embolism. The technique and the indication for this procedure as well as the intraoperative monitoring options are discussed.
Adult↗
Accuracy of intramedullary templates in femoral and tibial radiographs.
The accuracy of templates used for the preoperative planning of the fixation of intramedullary fractures depends on radiological magnification. To study the accuracy of these templates, we randomly selected 100 femoral and 100 tibial radiographs taken after stabilisation by an intramedullary nail using a standard technique. We then compared the known nail length with the corresponding measurements on the radiographs. The mean magnification factor for the femur was 9% and for the tibia 7%; these differ considerably from the range of magnification of the manufacturers' templates (femur, 15% to 17%; tibia 10% to 15%). We conclude that templates are unreliable for the selection of implant length and that this should be done by intraoperative measurements.
Bone Nails↗
[Intramedullary nailing of open fractures].
The goal of treatment of open fractures is to prevent infection, promote fracture healing, and restore normal limb alignment and function. The initial treatment of these fractures includes: debridement, soft tissue coverage, antibiotic therapy, and fracture stabilization. Four different techniques for intramedullary nailing for the fixation of open fractures have been employed: (1) unreamed, unlocked nails (i.e., Ender and Lottes, which have low infection rates, but are mechanically insufficient); (2) reamed unlocked nailing (which relies on overreaming to provide stability through bone-nail surface contact, but is associated with high infection rates); (3) reamed locked nailing (which may rely on limited reaming because of the interlocking screws); and (4) unreamed nailing (which always relies on interlocking screws and is associated with function better than and infection rates similar to those with external fixation, but has an increased incidence of screw breakage). In contrast to the biological problems in the tibia, those problems encountered in the femur are more predominantly mechanical in origin. For humeral shaft fractures, shoulder problems associated with the antegrade approach are frequent, and bypassing the rotator cuff with a retrograde approach appears advantageous.
Anti-Bacterial Agents↗
[Rupture of the posterior cruciate ligament: status of current treatment].
The posterior cruciate ligament acts as a complex system and is formed by the anterolateral an posteromedial bundle an the meniscofemoral ligaments. The main function of the ligament is stabilization of the tibia against posterior subluxation in flexion of the knee. Isolated PCL deficiency is compensated by increased quadriceps action in many patients for years, although natural history studies demonstrate retropatellar and medial osteoarthritis after 5-15 years in a not yet defined percentage. Osseous avulsion of the PCL from the tibia have a good prognosis when treated by open reduction and stable fixation. Ruptures of the ligament should not be treated by suture repair, since this technique has failed to restore posterior knee stability in most studies. Augmented repair and reconstruction of the ligament tend to improve the objective results, although the clinical data are not yet conclusive. Complex posterior instability should be treated by acute ligament reconstruction, since the results of conservative treatment are inferior and operative treatment in chronic complex posterior instability is extremely difficult. Potential osseous abnormalities (varus morphotype) and posterolateral rotatory instability must be addressed in these cases. PCL reconstruction with a patellar tendon graft can be performed with a two tunnel technique or with a Femur tunnel and a direct tibial graft fixation via a posterior approach. The results reported in the literature do not support the use of augmentation devices in PCL surgery.
Follow-Up Studies↗
[Distal femoral fractures. Transarticular reconstruction, percutaneous plate osteosynthesis and retrograde nailing].
Techniques for operative treatment of supra- and intercondylar fractures have changed in recent years. Some of these changes have come about in reduction techniques and implant selection. Operative approach concepts, which had remained unchanged for several decades, have been critically evaluated and modified, leading to a minimally invasive osteosynthesis (MIO) with transarticular joint reconstruction, closed plate positioning techniques or retrograde intramedullary nailing. These techniques result in better operative visualization and management of intraarticular comminution, safer fracture healing and better functional outcome. New strategies and techniques for the avoidance of axial malalignment, rotational deformities and leg length discrepancies are described.
Bone Plates↗
[A new procedure for determining leg length and leg length inequality using ultrasound. II: Comparison of ultrasound, teleradiography and 2 clinical procedures in 50 patients].
The clinical methods still in common use for measuring leg length and leg length discrepancy (LLD) cannot always meet the demands of precision and accuracy. A method using ultrasound is presented and shown to be a standardized, non-invasive method allowing accurate determination of leg length and LLD. Once the validity had been proved experimentally, practical handling, precision and accuracy of this method were tested on 50 patients in whom teleradiography of the lower extremity was performed for different reasons. The sonographically determined measures of LLD were compared with the radiographic measurements and in addition clinical measurements were taken by direct (tape measure) and indirect methods ("lengthening" of the shorter leg by wooden blocks of known thickness). Adjustments to the ventral hip joint and to the medial knee joint served as standardized, easily reproducible sonographic reference points. The mean variance of repeated sonographic measurements as a reflection of precision amounted to 3.5 mm2 for leg length measurement, with a maximum of 13.5 mm2. In the case of LLD the mean divergence between sonographically and radiographically determined LLD was 0.9 +/- 2.7 mm, with a maximum of 6.4 mm. The clinical methods with mean divergence of -1.2 +/- 9.6 mm (direct method) and -1.0 +/- 6.1 mm (indirect method) proved to be less accurate. The method examined for measuring leg lengths and LLD by means of ultrasound is easy to manage and non-invasive. Its precision and accuracy make it superior to clinical measuring methods and could even make some radiographical examinations superfluous.
Adult↗
[Development and initial clinical use of an aiming device for distal boring in interlocking nailing without roentgen image intensifier for the unreamed tibial nail].
An aiming technique for an unreamed tibial nail was developed, which uses the relatively constant distance between the first transverse 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 fine tuning is finally resolved by use of a "working channel" with a 10 mm diameter from the medial side. The aiming system was tested in 20 cases in a video-documented prospective study using the unreamed tibial nail (UTN, Synthes) between July 1993 and March 1995. In all cases (100%) distal locking could be performed without image intensification. With a high percentage (55%) of open fractures (3 O3B fractures) the total operation time was 108 min (median, range 60-180 min). The time for distal locking (always 3 bolts) was 15.5 min (median, range 8.0-39.0 min), while the time for proximal locking (average 1.6 +/- 0.7 bolts) was 4.5 min (median, range 3.0-15.0 min). There were no major intra- or postoperative complications related to the aiming system. The major advantages are that it is not necessary to have image intensification for distal locking, there is a reduction in radiation exposure for the surgeon, and the drill holes are very precise.
Adolescent↗