Search

Background: Currently, periarticular knee joint osteotomies are an integral part of the treatment of early arthritic deformities in the knee joint., Diagnostics: Analysis of the deformity is performed with a standardized full-leg standing x‑ray of both legs, as well as a lateral x‑ray of the knee joint that includes 2/3 of the proximal tibial shaft. An MRI examination of the knee joint is obtained to assess the articular cartilage, the ligaments and menisci. Torsion angle measurements with the CT/MRT supplement the diagnostics if necessary. Knowledge of normal physiological values and their standard deviations of the mechanical leg axis and the joint angles around the knee is obligatory., Therapy: The osteotomy is performed as close as possible to the femoral and/or tibial deformity. Postsurgical deformities including pathological patella position or a significant difference in leg length must be prevented. A description of proximal tibia opening or closing wedge osteotomies based on the nomenclature of the joint angles by Paley is presented. The indications for the various osteotomy techniques in the coronary plane are discussed in detail., (© 2023. The Author(s), under exclusive licence to Springer Medizin Verlag GmbH, ein Teil von Springer Nature.)

De novo genome assembly is a fundamental problem in computational molecular biology that aims to reconstruct an unknown genome sequence from a set of short DNA sequences (or reads ) obtained from the genome. The relative ordering of the reads along the target genome is not known a priori , which is one of the main contributors to the increased complexity of the assembly process. In this article, with the dual objective of improving assembly quality and exposing a high degree of parallelism, we present a partitioning-based approach. Our framework, BOA (bucket-order-assemble), uses a bucketing alongside graph- and hypergraph-based partitioning techniques to produce a partial ordering of the reads. This partial ordering enables us to divide the read set into disjoint blocks that can be independently assembled in parallel using any state-of-the-art serial assembler of choice. Experimental results show that BOA improves both the overall assembly quality and performance., Competing Interests: The authors declare no competing interests., (© 2022 The Author(s).)

Background: Rotational malalignment after intramedullary nailing of tibial shaft fractures is not uncommon. In-toeing and out-toeing conditions in children are often the reason for orthopedic and traumatological medical consultation., Objective: Evaluation of diagnostic modalities and therapeutic options for rotational malalignment in relationship to the patient's age. Surgical indications and efficacy of specific surgical techniques., Material and Methods: Systematic literature search in the German Institute for Medical Documentation and Information (DIMDI) and MEDLINE and evaluation of the currently published articles., Results: In adults computed tomography (CT) scanning is the gold standard for measuring the rotational alignment of the lower leg. To avoid exposure to ionizing radiation, magnetic resonance imaging (MRI) is currently the preferred modality in children and adolescents. The indications for corrective osteotomy are dependent on the functional complaints as well as the rotation angle measured by CT or MRI. Presently, there is no published study which demonstrates a correlation between rotation of the lower leg and the development of arthrosis in the knee or ankle joint. When a rotational osteotomy above the tibial tubercle is performed, correction of the rotation and the distance between the tibial tuberosity and the trochlear groove (TT-TG) and therefore patellofemoral imbalance can be effectively treated. Treatment of rotational malalignment after tibial shaft fractures is performed by diaphyseal osteotomy with intramedullary nail stabilization. In children, supramalleolar rotational osteotomy with subsequent locking plate osteosynthesis or stabilization using external fixation is performed for torsion correction., Conclusion: If there is a suspicion of rotational malalignment in the lower leg, a CT scan can be performed in adults and MRI in children and adolescents. Surgical indications for corrective osteotomy are dependent on functional complaints as well as the CT and MRI measurements. The CT and MRI reference values are only published according to the method of Waidelich et al. and Jend et al.

Non-union of the pediatric lateral humeral condyle following post-traumatic cubitus valgus is a severe complication after inadequate treatment. We report on a then 14-year-old male patient who developed an increasingly defective position in terms of cubitus valgus after conservative treatment of a lateral humeral condyle fracture. After performing screw osteosynthesis and achieving consolidation, a successful supracondylar dome osteotomy was performed which led to relief from pain and free range of motion of the elbow joint.

Background: Computer-assisted surgery (CAS) can act as an intraoperative ruler in high tibial osteotomy (HTO) to visualize continuously the leg during surgery., Questions: The aim of the study is to evaluate the accuracy of CAS with respect to preoperative planning and postoperative deviation from the planned leg axis in HTO. In addition, the influence of surgeon experience as well as operation time and perioperative complications are analyzed., Methods: A prospective multicenter study case series with follow-up at 6 weeks was performed in six centers. Medial open-wedge HTO with Tomofix(®) was done using computer assisted navigation technique with the Brainlab VV Osteotomy 1.0 module., Results: Fifty-one patients with medial gonarthritis were treated with navigated HTO. The follow-up rate was 98%. The majority of HTO-CAS patients fell within the tolerated limit of ±3° for leg axis deviation, however, seven patients were reported with deviations outside of this range: three patients had deviations of >3°-4.5° and four patients >4.5°, respectively. Eight intraoperative complications were documented, partially resulting from technical problems associated with the navigation system. During the 6-week follow-up period, three postoperative complications were experienced, all not associated with navigation technology., Conclusions: In about 85% of cases, a perfect result in terms of deviation of the planned mechanical leg axis could be achieved. Computer assistance in HTO proved to be a helpful tool regarding intraoperative control of leg axis., Level of Evidence: Level I, High quality prospective study (all patients were enrolled at the same preoperative planning point with ≥80% follow-up of enrolled patients).

Background: Bone deformities are typically identified through standard radiograms. Since X-ray examinations are easily applied and offer high quality imaging, noninvasive techniques are not commonly used in bone diagnostics. Nevertheless, nonradiological techniques are considered necessary because of the harmful effects of X-ray radiation., Methods: The paper presents a new noninvasive system for bone imaging. The system allows the physician to create self-defined templates of the measured geometrical parameters and to measure the bone geometry according to the planned procedures., Results: The proposed system was verified by determining the fiducial location error, the fiducial registration error and the target registration error. The tests were performed on sawbones and a measuring plate. In order to verify the accuracy of reconstruction, tests on the three-dimensional phantoms were carried out. The system has been tested in clinical conditions: results of limb geometrical parameters measured on five probands were compared with MRI-based evaluation., Conclusions: The system supplies critical data supporting the standard radiological examination. In the future, after further improvements it may replace invasive X-ray imaging. The main advantage of ultrasonography is noninvasive imaging (using mechanical waves), however, it demands considerable experience., (Copyright © 2011 John Wiley & Sons, Ltd.)

Background: The increasing use of fluoroscopy-based surgical procedures and the associated exposure to radiation raise questions regarding potential risks for patients and operating room personnel. Computer-assisted technologies can help to reduce the emission of radiation; the effect on the patient's dose for the three-dimensional (3-D)-based technologies has not yet been evaluated., Questions/purposes: We determined the effective and organ dose in dorsal spinal fusion and percutaneous transsacral screw stabilization during conventional fluoroscopy-assisted and computer-navigated procedures., Patients and Methods: We recorded the dose and duration of radiation from fluoroscopy in 20 patients, with single vertebra fractures of the lumbar spine, who underwent posterior stabilization with and without the use of a navigation system and 20 patients with navigated percutaneous transsacral screw stabilization for sacroiliac joint injuries. For the conventional iliosacral joint operations, the duration of radiation was estimated retrospectively in two cases and further determined from the literature. Dose measurements were performed with a male phantom; the phantom was equipped with thermoluminescence dosimeters., Results: The effective dose in conventional spine surgery using 2-D fluoroscopy was more than 12-fold greater than in navigated operations. For the sacroiliac joint, the effective dose was nearly fivefold greater for nonnavigated operations., Conclusion: Compared with conventional fluoroscopy, the patient's effective dose can be reduced by 3-D computer-assisted spinal and pelvic surgery., Level of Evidence: Level II, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

Background: Elastic stable intramedullary nailing has become a popular treatment for pediatric long-bone fractures. However, early limb malalignment and length differences may occur in children with femoral fractures who are managed with this procedure., Methods: We prospectively followed sixty-eight children (mean age, 5.6 years) who were managed with elastic stable intramedullary nailing for the treatment of a unilateral femoral shaft fracture in order to evaluate early angular or rotational malalignment or limb-length discrepancy. The average body weight was 21 kg (range, 10 to 45 kg). There were fifty-seven AO/ASIF Type-A fractures and eleven Type-B fractures. Malalignment was assessed with use of radiographs, computed tomography, or navigated ultrasound examination after four to seven months to evaluate the short-term result of fixation and to eliminate changes caused by later bone remodeling., Results: The mean femoral length difference was 0.5 mm of femoral lengthening. Only eleven patients (16%) had a limb-length discrepancy of >10 mm. Mechanical axial deviation of >5 degrees occurred in one patient. However, the mean femoral rotational angle difference was 14.5 degrees . Thirty-two children (47%) had > or =15 degrees of torsional malalignment., Conclusions: Elastic stable intramedullary nailing can provide satisfactory results in terms of limb length and axial alignment, but a high rate of early torsional malalignment may be seen.

The aim of the present study was the verification of the accuracy of 2D fluoroscopy-based navigated pedicle screw placements at the thoracic and lumbar spine in a case series of traumatised patients. Within 36 months 111 pedicle screws were instrumented using C-arm based navigation in 29 patients, 60 at the thoracic and 51 at the lumbar spine. All screw positions were evaluated postoperatively by a routine thin-slice CT scan using multiplanar reconstruction. The position of a screw in relation of its pedicle was classified as: a) screw completely intraosseous, b) screw perforated less than thread level and c) screw perforated over thread level. In 34 thoracic (56.7%) and 32 lumbar (62.7%) screws complete intraosseous placement was observed, 14 thoracic screws (23.3%) and 14 lumbar screws (27.5%) perforated less than thread level. Perforations over thread level were found in 12 thoracic (20%) and 5 lumbar (9.8%) screws. Only medial and lateral perforations of the pedicle were documented (without neurological signs), cranial or caudal perforations did not occur. Segmentation of the C-arm navigation into two comparable treatment periods showed a learning curve with a reduction of perforations in the second sequence (after 57 pedicle instrumentations) of about 15%, this was not found to be statistically significant. The fluoroscopic navigation of pedicle screws is a safe procedure at the lumbar spine with equal accuracy compared to the non-navigated conventional instrumentation. Application of C-arm navigation at the thoracic spine showed more inaccuracies, so that 3D-based navigation seems to be more advantageous in this region.

The aim of the present study was the verification of the accuracy of 2-D fluoroscopy-based navigated pedicle screws at the thoracic and lumbar spine in a case series of traumatised patients. Within 36 months 111 pedicle screws in 29 patients were instrumented using C-arm based navigation, 60 at the thoracic and 51 at the lumbar spine. All screw positions were evaluated postoperatively by a routine thin slice CT scan using multiplanar reconstruction. The position of a screw in relation to its pedicle was classified in a) screw completely intraosseous, b) screw perforated less than thread level and c) screw perforated more than thread level. In 34 thoracic (56.7%) and 32 lumbar (62.7%) screws complete intraosseous placement was observed, 14 thoracic (23.3%) and 14 lumbar (27.5%) screws perforated less than thread level. Perforations more than thread level were found in 12 thoracic (20%) and 5 lumbar (9.8%) screws. Only medial and lateral perforations of the pedicle were documented (without neurological signs), cranial or caudal ones did not occur. Segmentation of the C-arm navigation into two comparable treatment periods showed a learning curve with a reduction of perforations in the second sequence (after 57 pedicle instrumentations) of about 15%, this was found to be not statistically significant. The fluoroscopic navigation of pedicle screws is a safe procedure at the lumbar spine with equal accuracy compared to the non-navigated conventional instrumentation. Application of C-arm navigation at the thoracic spine showed more inaccuracies, so that 3-D-based navigation seems to be advantageous in this region.

Navigation systems track objects with precision expressed as root mean square equalling even up to 0.15 mm. Application of navigation system combined with imaging technique makes surgical operations less invasive, which results in the reduced risk of infection, smaller scar and a shorter time of rehabilitation. Imaging techniques allow surgeon to create individual virtual models for virtual surgery planning. Navigation system tracks the positions of surgical tools in relation to the patient's coordinate systems. Medical imaging enables low-invasive surgery, whereas the position of surgical instruments is monitored on screen. The paper presents a newly developed computer-aided surgical system consisting of ultrasonographic probe and tracking system to measure bone geometry, design surgical scenario virtually and follow it intraoperatively. The system assists surgeon to correct bone deformities. The paper presents the results of several accuracy tests, which demonstrate good repeatability and accuracy.

In this study, we present a new 2.5-dimensional ultrasonic navigation system for measuring axes, lengths, and torsions preoperatively, intraoperatively, and postoperatively. The system comprises an ultrasound unit with a 5-MHz linear probe (TELEMED Echoblaster 128; Telemed, Vilnius, Lithuania) and a navigation system (OrthoPilot; B. Braun Aesculap, Tuttlingen, Germany) with a Polaris camera (Northern Digital, Waterloo, Canada). Specialized software developed for this application allows for selecting any body region on a virtual 3D skeleton. With a virtual ultrasound probe, planes needed for measurements can be defined. For each section, the respective surface contour of the bone, which is also shown in the ultrasound image, is displayed. Alternatively, the clinician can use established standard sections. Finally, the required length, axes, and torsions are defined. The accuracy and precision of the system were tested using a plastic model. The measurements of length, torsion, and axis values were accurate to -0.1 +/- 0.3 mm (95% CI), 0.1 degree +/- 0.2 degree (95% CI), and 0.0 degree +/- 0.006 degree (95% CI), respectively. The precision variances for length, torsion, and axis were 1.17 mm (standard deviation) and 0.94 degree and 0.66 degree. These results suggest that the new sonographic method is more accurate than conventional radiographic techniques.

Several techniques for knee fusion have been described with success rates ranging from 29% to 100%, with worse results occurring in patients with joint sepsis. We treated 21 patients with persistent infections using knee arthrodesis with a hybrid Ilizarov frame at our institution. There were 13 men and eight women ranging from 21 to 75 years (mean, 49.7 years). Sixteen patients had chronic osteomyelitis and five had previous fusion trials. Two patients required bone transport using the same arthrodesis frame. We corrected associated malalignment in three patients. Solid knee fusion was achieved in all but one patient after a mean external fixation time of 22.7 weeks (range, 11-47 weeks). Limb shortening averaged 2.8 cm (range, 1.5-5 cm). No patients required secondary bone grafting to achieve fusion. Nine patients had complications develop, three of whom required reresection and frame application to treat persistent infection or delayed union. Our results emphasize the clinical success of using the Ilizarov fixator for knee arthrodesis after persistent sepsis.

Background: Torsional malalignment and mechanical axis deviation (MAD) are worrisome complications after nailing of distal femoral fractures. Variable, sometimes contradictory, reports about these problems have been published., Methods: In a retrospective nonrandomized study, 41 patients (mean age, 44.5 years) with distal third femoral fractures that were operatively treated using either antegrade (20 cases) or retrograde (21 cases) intramedullary nailing during a period of 2 years have been reviewed. Goniometric measurement was done using a navigated ultrasound examination whereas functional evaluation and return to sports were assessed using Merle d'Aubigné functional grading system and Tegner and Lysholm activity score., Results: There was no difference in femoral length, torsion, or MAD between patients treated using antegrade nails and those treated with a retrograde nail. There was a greater limitation of knee motion with retrograde nailing and of hip motion with antegrade nailing. The functional grading and activity evaluation showed, however, no difference between both groups., Conclusions: The study cohort showed that no treatment method had proved an advantage over the other regarding limb geometry or the functional outcome. The proper operative indication, intraoperative control, and the surgeon's experience seem to be more important in this regard than the nailing technique.

Seventy-three children (48 boys and 25 girls; mean age, 5.7 years) with unilateral femoral or tibial shaft fractures were treated using elastic intramedullary nails at the authors' institution. There were 61 simple type A fractures (84%) and 12 wedge type B fractures (16%). All but 3 children had closed fractures. Associated injuries were seen in one third of the cases. All fractures were reduced by closed manipulation. Union was achieved in all cases without additional intervention. Technical problems occurred in few patients. Improper nail length was seen in 4 cases. None of the study patients developed deep infection. No angulation greater than 15 degrees was found after femoral fractures. Nine patients had length discrepancy greater than 10 mm. Spiral fractures showed a tendency for shortening whereas transverse fractures were more associated with post-traumatic lengthening. No significant axial malalignment or shortening was seen in tibial fractures. Torsional differences of greater than 15 degrees were detected by computed tomography or navigated ultrasound examination in nearly half of the patients; however, only 4 children had clinically apparent gait changes. The study confirms the satisfactory results of treating pediatric lower limb fractures using elastic nails. Proper surgical technique and intraoperative control of limb alignment can help avoid postoperative deformities.

Navigation systems for operative assistance in knee joint surgery have been established in the last 5 years. Among the large number of variable systems, the image-free kinematic systems have won widespread acceptance. The C-arm based systems are not superior to the image-free systems. The CT-based systems are advantageous in completely destroyed joints (with marked joint erosion) or advanced congenital or traumatic deformities. The intraoperatively-performed Iso-C (3D) technique presents data sets in CT-quality, but because of its small data volume currently is limited to the reconstruction of articular surfaces following fractures. The use of image-free navigation in resurfacing knee arthroplasty is in the meantime beyond controversy whereby deviations in the mechanical axis from normal values can be significantly reduced. For high tibial osteotomies navigation modules will be soon available for marketing. However, with these modules, intraoperative imaging is indispensable, but it will be image-free in the future. The early clinical results are promising. Cruciate ligament navigation is not yet a clinical standard be-cause of the considerable associated time expenditure. The appropriate modules are still under development.

The indications for physiotherapy after supracondylar humeral fractures in children are not clear in the literature, even in the presence of an active or passive limitation of elbow joint motion. The authors therefore performed a prospective randomized study to assess the effectiveness of physiotherapy in improving the elbow range of motion after such fractures. The authors studied two groups of 21 and 22 children with supracondylar humeral fractures Felsenreich types II and III, all without associated neurovascular deficits. All children were treated by open reduction and internal fixation with Kirschner wires inserted from the radial side of the humerus. Postoperative follow-up at 12 and 18 weeks showed a significantly better elbow range of motion in the group with weekly physiotherapy, but there was no difference in elbow motion after 1 year. In each group, one child had an extension deficit of 15 or 20 degrees. The authors conclude that postoperative physiotherapy is unnecessary in children with supracondylar humeral fractures without associated neurovascular injuries.

Introduction: Conventional retrograde nailing of the femur causes two important disadvantages: the proximal locking of the nail is difficult because of the anatomic conditions and a chondral defect was left into the knee., Material and Methods: After the retrograde implantation the new nail was lead through the greater trochanter. An additional proximal aiming device for proximal interlocking can be fixed. The entrance portal will be sealed by an osteochondral cylinder. 50 cases of femur fractures were selected for the prospective study. We recorded all intraoperative complications and technical difficulties. The cases were followed up for 52 weeks, both clinical and radiology examinations were performed., Results: The mean follow up was 15.5+/-5 months. All fractures were healed. Knee movement was 125+/-14 degrees. The Leung Score was 84+/-12.6 points; HSS Score was 90+/-9 points. In two cases wound infections were developed. Mal-union was observed in three cases, in two cases nail brake down., Conclusions: The new retrograde interlocking nail could be used to manage femur fractures successfully. Two aiming devices enable a easy interlocking. Replacement of the osteochondral cylinder into the entry portal reduces cartilage damage.

Objective: The objectives of this study are to design and evaluate a CT-free intra-operative planning and navigation system for high tibial opening wedge osteotomy. This is a widely accepted treatment for medial compartment osteoarthritis and other lower extremity deformities, particularly in young and active patients for whom total knee replacement is not advised. However, it is a technically demanding procedure. Conventional preoperative planning and surgical techniques have so far been inaccurate, and often resulting in postoperative malalignment representing either under- or over-correction, which is the main reason for poor long-term results. In addition, conventional techniques have the potential to damage the lateral hinge cortex and tibial neurovascular structures, which may cause fixation failure, loss of correction, or peroneal nerve paralysis. All these common problems can be addressed by the use of a surgical navigation system., Materials and Methods: Surgical instruments are tracked optically with the SurgiGATE((R)) navigation system (PRAXIM MediVision, La Tronche, France). Following exposure, dynamical reference bases are attached to the femur, tibia, and proximal fragment of the tibia. A patient-specific coordinate system is then established, on the basis of registered anatomical landmarks. After intra-operative deformity measurement and correction planning, the osteotomy is performed under navigational guidance. The deformities are corrected by realigning the mechanical axis of the affected limb from the diseased medial compartment to the healthy lateral side. The wedge size, joint line orientation, and tibial plateau slope are monitored during correction. Besides correcting uni-planar varus deformities, the system provides the functionality to correct complex multi-planar deformities with a single cut. Furthermore, with on-the-fly visualization of surgical instruments on multiple fluoroscopic images, penetration of the hinge cortex and damage to the neurovascular structures due to an inappropriate osteotomy can be avoided., Results: The laboratory evaluation with a plastic bone model (Synbone AG, Davos, Switzerland) shows that the error of deformity correction is <1.7 degrees (95% confidence interval) in the frontal plane and <2.3 degrees (95% confidence interval) in the sagittal plane. The preliminary clinical trial confirms these results., Conclusion: A novel CT-free navigation system for high tibial osteotomy has been developed and evaluated, which holds the promise of improved accuracy, reliability, and safety of this procedure.

Previous studies have compared the functional outcome and torsional differences following closed intramedullary nailing of femoral fractures. Rotational deformity following intramedullary nailing may cause symptoms and require surgical correction by osteotomy. Until now studies were designed to evaluate the correct torsional differences by examining every patient following antegrade or retrograde femoral nailing. The series included 13 women and 28 men, average age 44.5 years, who suffered a fracture of the distal femoral diaphysis. Postoperatively we established the diagnosis by three-dimensional determination of the torsion and length of the lower extremities by ultrasound measurement. Furthermore, we performed the clinical examination according to the Tegner and Lysholm score and the Merle d'Aubigne score. There were no significant differences in torsional deformity and length found. The functional outcome showed no significant differences between the two groups. The functional examination exhibited a reduction of flexion in knee motion in the retrograde group. In the antegrade group the motion of the hip was decreased. A correlation between the functional outcome and the torsional deformity was not found. The possible advantage of positioning by using the retrograde femoral nail was not verified.

Today the most common application in the field of computer-assisted surgery is navigated total knee arthroplasty. During the last 5 years the imageless kinematic navigation systems have gained wide acceptance. As several prospective randomized studies could show, the standard deviation of the mechanical axis is reduced significantly by these techniques. However, the direction of the mechanical axis is only one factor which influences the long-term results of total knee arthroplasty. Further important factors are ligament balancing and position of the femoral and tibial components in all three planes. Up to now no studies have been able to show a significantly better functional result, a more rapid recovery, or a decreased complication rate. Drawbacks of the navigation systems are the additional costs and the additional operation time between 15 and 20 min. Therefore, navigated total knee arthroplasty is not yet a standard procedure, but this technique is well on the way to becoming the gold standard in the future.

High tibial osteotomy is a widely accepted treatment of medial compartment osteoarthritis as well as other lower extremity deformities. However, it is a technically demanding procedure. The lack of exact intraoperative real time control of the mechanical axis often results in postoperative malalignments, which is one reason for poor long term results. These problems can be addressed with the use of a surgical navigation system. Following exposure, dynamic reference bases (DRBs) are attached to the femur, and the proximal and the distal part of the tibia. After intraoperative measurement of the deformities and correction planning, the osteotomy is performed under navigational guidance. The wedge size, joint line orientation, and tibial plateau slope are monitored during correction. The in vitro evaluation with a plastic bone model suggests that the error of deformity correction is less than 1.7 degrees (95% confidence limits) in the frontal, and less than 2.3 degrees (95% confidence limits) in the sagittal plane, respectively. On a cadaver study of 13 legs, the mechanical axis intersected the Fujisawa line in 80.7% (range 77.5-85.8%). The preliminary clinical experience confirms these results. A novel computer tomography free navigation system for high tibial osteotomy has been developed that holds the promise of improving the accuracy, reliability, and safety of this kind of approach.

The surgical correction of malalignments of the lower extremities is a very demanding procedure. It requires extensive knowledge of: (1) fundamental lower extremity biomechanics, (2) various diagnostic modalities, and (3) methodology for multidimensional preoperative planning. Despite advanced techniques in diagnostics and surgery, the history of the patient and a physical examination are still the first steps in the diagnostic chain. The knowledge of the method-dependent normal values, their physiological range and intra-individual differences are a prerequisite. In posttraumatic deformities, the healthy leg is a good reference for the patient's geometric orientation. As a rule, values differing by three times the standard deviation or more are good indications for an operation. These are 15 and 12 mm for the upper and lower leg, 18 and 15 mm for the whole leg and only 3 degrees mm for the mechanical leg axis measured using computer tomography and long standing x-rays, respectively. The indication for surgical correction is not only based on geometric data. The patient's functional needs, symptoms, complaints and compensation possibilities must also be taken into account. The lower extremities have to be assessed in a psychosocial context. Among the huge number of possible surgical techniques, the procedure best suited for the patient has to be selected. This requires extensive knowledge and advanced technical skills from the treating orthopaedic surgeon. In supracondylar or high tibial osteotomies for the treatment of medial arthritis of the knee joint, the patient should be informed of the long term prognosis and endoprosthetic alternatives. Today, percutaneous epiphysiodesis is a very reliable and minimally invasive surgical technique for correcting the length and axis of the lower extremity in children between 10 and 14 years. With well planned epiphysiodesis procedures, it is often possible to avoid complex osteotomies in younger patients.

This paper discusses an operation planning system for correction osteotomies. It is based on 3D data obtained from CT/MR of the bone and it allows to perform a 3D planning. The physician can individually determine anatomical landmarks for measuring geometric parameters of the bone like length, angle and torsion angle. In a virtual scene he or she can set a single cut or can remove/insert a wedge, dissecting the bones. The bone parts can be rearranged in 3D space. Optimization routines allow that the physician only defines the position of the cut, the orientation of the cut plane, the rearrangement of the bone and the optimization for the maximal overlap of the cortical bone can be processed automatically. The system is currently in use at the Trauma department at the University of Ulm. A case study shows the results by applying this system.

The application of x-ray diagnostics for intraoperative navigation and for registration of hard tissue structures is restrained due to high radiation loads and the not given real time ability. Previous approaches with conventional ultrasonic imaging are only interactively applicable due to the high information content of soft tissue optimised B-mode-images. A pure image processing does not allow an automatic identification of individual structures, so that this must be done by the physician. To decrease the high expense of time, this report presents a concept for an adapted chain of rf-signal processing as well as an ultrasonic system for the contrast-enhanced representation of tissue borders. The system permits an exact measurement of the body geometry, which is demonstrated by determining the position of the pelvis entry plane.

Deformities of the distal femur are usually corrected by supracondylar osteotomy. In the "classical" procedure the bone cut is performed with an oscillating saw, and internally fixed using a plate. This technique is hampered first by an invasive approach and second by limited corrective options in case of complex deformities. A supracondylar bone cut by focal dome osteotomy or drill osteoclasis in combination with internal fixation by retrograde intramedullary nailing (RN) might be a promising alternative procedure. 12 patients with multidimensional post-traumatic deformities of the distal femur were prospectively enrolled in a study to investigate this new minimal-invasive technique. In all patients a meticulous analysis of leg geometry was done pre- and postoperatively. Details of operative planning, osteotomy and fixation procedure are given as well as the postoperative treatment. 7 corrective osteotomies were one-step procedures, in 5 patients additional lengthening over the RN was performed using unilateral external fixation. The mean follow-up was 15 (range 7-27) months. All of the osteotomies healed in a normal expected time frame. All patients had important functional benefits. In 11 patients the goal of deformity correction was achieved. In one patient the correction in the frontal plane remained insufficient. 6 months after the completion of femoral lengthening osteomyelitis developed in one patient, probably due to a pin-track infection. The infection subsided after early removal of the RN. No further complications were observed. The presented technique is demanding concerning pre-operative planning and surgical realization but it offers a minimal-invasive and promising approach for the correction of multidimensional femoral deformities.

The presented approach is the realization of a minimal invasive treatment of pelvis fractures using the computer aided surgery (CAS). Main problem of tracking of major bone fragments after reposition is solved by implementing of 3D ultrasound to obtain intraoperative bone surfaces. Preoperative and intraoperative data sets are matched. Major fragments are tracked. The real time navigation is possible.

This paper describes a novel approach to correct osteotomy deformities of long bones using virtual reality and image processing techniques on personal computers. The discussed method allows to simulate osteotomy corrections by implementing a single cut and a rearrangement of the dissected bone parts. It allows the surgeon to directly control the pre-operative situation and the post-operative result of the simulation by comparing bone-length, angles, and torsion of the bone. In addition, he or she obtains the coordinates and angles of the planned cut relative to anatomical landmarks.

In a prospective randomized clinical trial, ADCON-T/N was investigated with regard to its effectiveness in fresh traumatic injuries of the flexor tendons in Zone II of the hand. Thirty patients participated in the trial. Following a standardized technique of tendon repair, the total active motion (TAM) and total extension lag (TEL) were determined after 12 weeks and evaluated according to the Buck-Gramcko score. Excellent results were achieved in 15 out of 16 patients in the ADCON-T/N group and 12 out of 14 in the control group. However, no statistically significant difference was found between the mean TAM and TEL in the two groups., (Copyright 2000 The British Society for Surgery of the Hand.)

Posttraumatic malalignments are a frequent sequlae of IM nailing of lower extremity fractures. Conventional US has proven to be inferior to CT determinations of tibial or femural length and torsion. A new 3-D US method is presented that allows for accurate single step determination of lower extremity length and torsion without ionizing radiation. A regular US machine with a 5 Mhz linear probe is combined with an US localizer. Reference markers affixed to the lower extremity eliminate errors associated with patient position or motion. The 3-D US method was compared against CT (Ulm's method) in the measurement of torsion and length of the tibia and femur in 50 adults and 50 children. In both methods, the maximum difference of the intraindividual torsional angles and length measurements was 7 degrees and 7 mm. The maximum standard deviation for reproducibility in length measurement was 1.6 mm and 1.5 degrees for angular torsion. The new 3-D US technique was superior to CT in terms of reliability and reproducibility. Clinical advantages of the 3-D US technique include rapidity, independence from patient motion or positioning and the avoidance of ionizing radiation. Indications for 3-D torsional and length determinations include follow-up evaluation of adult and pediatric tibial and femoral fractures, pediatric limb and gait evaluations, and osteotomy planning.

Because of different projections and axis constructions, the length and torsion of the lower extremities are sensitive to the measuring method. To judge pathological deformities in children or adolescents it is necessary to know the reference values. In this study, 78 children and adolescents 2-18 years old were included who had a femoral or tibial shaft fracture. Torsion and length were determined by computed tomography at least 3 months after internal fixation according the Ulm method. Only healthy bones were considered for this study. The mean internal torsion of the femur decreased during the growth period from 34.2 degrees +/- 10.3 degrees (x +/- SD) to 19.3 degrees +/- 9.5 degrees. There was only a weak correlation between the age and torsion of the femur. The mean external torsion of the tibia was 32.3 +/- 10 degrees. The 95th percentiles of the intraindividual torsional differences were 14 degrees (x = 4.1 degrees) of the femur (n = 30) and 12 degrees (x = 4.7 degrees) of the tibia (n = 48). The median femoral and tibial intraindividual length differences were 2 mm. The corresponding 95th percentiles were 10 and 9 mm. The aim of the study was to determine the age-dependent torsion and length and their respective differences with a standardized CT method. The range of the normal values was much greater than published in the literature.

Unlabelled: According to the current treatment protocol of the Cooperative Osteosarcoma Study (COSS), monitoring preoperative chemotherapy response and estimating grade of tumor regression in patients with osteosarcoma is mandatory before surgical removal of the tumor, particularly if a limb salvage procedure is intended. In addition, response to neoadjuvant chemotherapy is considered as an important prognostic indicator. The aim of this prospective study was to assess the usefulness of 2-(18F) fluoro-2-deoxy-D-glucose (FDG) PET in the noninvasive evaluation of neoadjuvant chemotherapy response in osteosarcoma., Methods: In 27 patients with osteosarcoma, we determined tumor-to-background ratios (TBRs) of FDG uptake with PET, before and after neoadjuvant chemotherapy according to COSS 86c or COSS 96 protocols, respectively. We compared changes in glucose metabolism of osteosarcomas with the histologic grade of regression in the resected specimen, according to Salzer-Kuntschik, discriminating responders (grades I-III; n = 17) and nonresponders (grades IV-VI; n = 10)., Results: The decrease of FDG uptake in osteosarcomas expressed as a ratio of posttherapeutic and pretherapeutic TBRs showed a close correlation to the amount of tumor necrosis induced by polychemotherapy (P < 0.001; Spearman). With a TBR ratio cutoff level of 0.6, all responders and 8 of 10 nonresponders could be identified by PET. In addition, lung metastases of osteosarcoma were detected with FDG PET in 4 patients., Conclusion: FDG PET provides a promising tool for noninvasive evaluation of neoadjuvant chemotherapy response in osteosarcoma. This could imply consequences for the choice of surgical strategy, because a limb salvage procedure cannot be recommended in patients nonresponsive to preoperative chemotherapy unless wide surgical margins can safely be achieved.

Basically, four post-traumatic conditions of the proximal femur can be improved by corrective osteotomies: recurring luxations and subluxations of the hip joint; necrosis of the femoral head; non-unions; deformities. Dependent on the individual situation, the following procedure can be recommended, including diagnosis of deformities and indication and therapy of corrective osteotomies: analysis of the problem from the viewpoint of history, clinical findings and imaging techniques; indication for corrective osteotomy; graphic planning; operation technique. Particularities of post-traumatic conditions with regard to diagnosis, indication and surgical technique are indicated. Only with perfectly tailored concepts can we respond to the individual situation of an individual patient and reflect the variety and complexity of post-traumatic conditions of the proximal femur.

The diagnosis of malalignments of the lower extremities includes analysis of the geometry of the whole leg. The first step in the diagnostic process is a standardized physical examination. It provides valuable background information for an effective radiological diagnosis. Even with a thorough standardized physical examination it is not possible to define exactly the deformity or decide on an operative procedure. The diagnosis of axis deviations in the frontal plane can be measured on a conventional plain X-ray of the whole leg. In this view it is very important that the knee joints are in a true a.p. view independent on torsional deformities of the lower legs. Today the gold standard to measure the torsion and length of the lower extremities is the CT scan. However, the multitude of analytical methods for CT measurements described in the literature do not lend themselves readily to comparison; thus, it is difficult to identify a clear method of choice. Not every CT measurement is better than a physical examination. Evidence of reproducibility and accuracy is a prerequisite for useful interpretation of the results. Up to this point in the literature there are only reference values for the Ulm CT Method. One alternative is the MR scan, which avoids radiological risks, but the reproducibility and accuracy of the MRI method are not as good as for the CT method. Another alternative is ultrasound, where recent advances in the measurement of torsion and length of the lower extremities have proven competitive with or superior to the accuracy of MRI. The three-dimensional determination of the torsion and length of the lower extremities by ultrasound has now assumed a leading role in the non-radiological diagnosis of malalignments of the lower extremities in children and adolescents. This method furthermore is increasingly being used in preoperative planning of leg deformities in adults.

Analysis of bony geometry of the lower limb comprises frontal, sagittal and longitudinal alignment, as well as length and torsion, including at first the whole leg and finally the femur and tibia separately. Clinical examination assesses the bony geometry, functional aspects, ligamentous and soft tissue conditions, etc. Frontal and sagittal radiographs indicate axial alignment and angles of the hip, knee and upper ankle joint. Apex and size of deformities are defined simultaneously. CT and ultrasound techniques allow the measurement of length and torsion of the whole leg, as well as of the femur and tibia separately, provided those techniques are standardized with proven reproducibility.

Corrective osteotomies are often planned and performed on the basis of normal anatomical proportions. We have evaluated the length and torsion of the segments of the lower limb in normal individuals, to analyse the differences between left and right sides, and to provide tolerance figures for both length and torsion. We used CT on 355 adult patients and measured length and torsion by the Ulm method. We excluded all patients with evidence of trauma, infection, tumour or any congenital disorder. The mean length of 511 femora was 46.3 +/- 6.4 cm (+/-2SD) and of 513 tibiae 36.9 +/- 5.6 cm; the mean total length of 378 lower limbs was 83.2 +/- 11.4 cm with a tibiofemoral ratio of 1 to 1.26 +/- 0.1. The 99th percentile level for length difference in 178 paired femora was 1.2 cm, in 171 paired tibiae 1.0 cm and in 60 paired lower limbs 1.4 cm. In 505 femora the mean internal torsion was 24.1 +/- 17.4 degrees, and in 504 tibiae the mean external torsion was 34.9 +/- 15.9 degrees. For 352 lower limbs the mean external torsion was 9.8 +/- 11.4 degrees. The mean torsion angle of right and left femora in individuals did not differ significantly, but mean tibial torsion showed a significant difference between right (36.46 degrees of external torsion) and left sides (33.07 degrees of external torsion). For the whole legs torsion on the left was 7.5 +/- 18.2 degrees and 11.8 +/- 18.8 degrees, respectively (p < 0.001). There was a trend to greater internal torsion in femora in association with an increased external torsion in tibiae, but we found no correlation. The 99th percentile value for the difference in 172 paired femora was 13 degrees; in 176 pairs of tibiae it was 14.3 degrees and for 60 paired lower limbs 15.6 degrees. These results will help to plan corrective osteotomies in the lower limbs, and we have re-evaluated the mathematical limits of differences in length and torsion.

Intraoperative control of torsion is delicate in intramedullary nailing of femur and tibia fractures. Post-traumatic torsional deformities cause clinical problems if the rotational 0-position, according to the neutral-0-method, cannot be attained or exceeded. The necessary precondition for every indication and planning of corrective osteotomies is conscientious analysis of the geometry of the lower extremities by clinical means, radiography and computed tomography. Operative procedures and techniques of corrective osteotomies in case of torsional deformities after intramedullary nailing are presented. Preoperatively, the intraindividual torsional differences in 15 patients with maltorsions of the femur were 33 degrees (-37/+50) and in 7 patients with maltorsions of the tibia 23 degrees (-21/+29). Positive signs indicate external and negative signs of internal maltorsions. Postoperatively, the intraindividual torsional differences were 6 degrees (-3/+14) in the femora and 7 degrees (+3/+12) in the tibiae. Therefore, the physiological torsional tolerance of 15 degrees was respected in all 22 patients. Additionally, limb lengthening was realized in 4 patients with shortening after intramedullary nailing of the femur. In 3 patients a one-step procedures with interposition of allogeneic cancellous bone in the osteotomy gap was performed and in one patient continuous callus distraction by external fixation.