[Periarticular knee osteotomies for pre-arthritic deformities in the frontal plane : Indications and surgical techniques]. / Frontale kniegelenksnahe Umstellungsosteotomien bei präarthrotischen Deformitäten : Indikationen und Operationstechniken.

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 x­ray of both legs, as well as a lateral x­ray 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.

Reliability of computer-assisted surgery as an intraoperative ruler in navigated high tibial osteotomy.

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).

Can computer-assisted surgery reduce the effective dose for spinal fusion and sacroiliac screw insertion?

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.

Limb geometry after elastic stable nailing for pediatric femoral fractures.

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.

Improving surgical precision--application of navigation system in orthopedic surgery.

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.

A new experimental measurement and planning tool for sonographic-assisted navigation.

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.

Limb malalignment and functional outcome after antegrade versus retrograde intramedullary nailing in distal femoral fractures.

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.

Flexible intramedullary nailing in pediatric lower limb fractures.

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.

Hybrid external fixation for arthrodesis in knee sepsis.

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.

Implementation, accuracy evaluation, and preliminary clinical trial of a CT-free navigation system for high tibial opening wedge osteotomy.

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.

The effectiveness of physiotherapy after operative treatment of supracondylar humeral fractures in children.

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.

Computer aided high tibial open wedge osteotomy.

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.