Peter Keppler

LENGTH AND TORSION OF THE LOWER LIMB

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.

Die sonographische Bestimmung der Beingeometrie

SummaryPosttraumatic 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 postition or motion. The 3-D US method was compared against CT (Ulms method) in the measurement of torsion and length of the tibia and femur in 50 adults and 50 children. In both methods, the maximum diffence 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 reliabilty and reproducibilty. Clinical advantages of the 3-D US technique include rapidity, independence from patient motion or postioning 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.ZusammenfassungPosttraumatische Fehlstellungen im Bereich der unteren Extremität sind vor allem nach intramedullärer Stabilisierung keine Seltenheit. Wegen mangelnder Reproduzierbarkeit und Genauigkeit konnte sich die sonographische Torsionswinkel- und Längenmessung nur bedingt gegen den bisherigen „Gold Standard“, die Computertomographie, durchsetzen. Hier wird ein neues sonographisches Meßsystem vorgestellt, das erstmals die Bestimmung der Längen und Torsionen im Bereich der unteren Extremität in einem Untersuchungsgang unter voller Berücksichtigung der dreidimensionalen Beingeometrie erlaubt. Dies wird durch die Kombination eines Ultraschallgeräts mit einem Ultraschallortungssystem erreicht. Referenzsensoren, welche am Unterschenkel des Patienten befestigt werden, machen das System gegen Rotationsbewegungen während der Messung unempfindlich. Die sonographisch ermittelten Torsionen und Winkel wurden bei 50 Kindern und 50 Erwachsenen mit den Ergebnissen der Computertomographie (Ulmer Methode) verglichen. In beiden Kollektiven betrug die größte Abweichung bei der Bestimmung der intraindividuellen Torsionswinkel- und Längendifferenzen 7 ° bzw. 7 mm. Die maximalen Standardabweichungen der Reproduzierbarkeit betragen 1,6 mm bei der Längenmessung und 1,5 ° bei der Torsionswinkelbestimmung. Das vorgestellte sonographische Meßsystem zeichnet sich durch eine zuverlässige und reproduzierbare Torsionswinkel- und Längenbestimmung aus. Die Messungen sind unabhängig von der Patientenlagerung und können schnell und einfach durchgeführt werden. Bewegungen während der Messungen werden registriert und automatisch korrigiert. Mögliche Einsatzbereiche sind die Verlaufskontrollen nach Frakturen bei Kindern und Jugendlichen, die Erfassung der Beingeometrie vor Korrekturosteotomien sowie die Qualitätskontrolle noch osteosynthetischer Versorgung von diaphysären Frakturen im Bereich der unteren Extremität.

Can Computer-assisted Surgery Reduce the Effective Dose for Spinal Fusion and Sacroiliac Screw Insertion?

BackgroundThe 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/purposesWe 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 MethodsWe 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.ResultsThe 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.ConclusionCompared 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.

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® 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° (95% confidence interval) in the frontal plane and <2.3° (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.

Torsionskorrekturen nach Marknagelosteosynthesen der unteren Extremität

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° (–37/+50) and in 7 patients with maltorsions of the tibia 23° (–21/ +29). Positive signs indicate external and negative signs of internal maltorsions. Postoperatively, the intraindividual torsional differences were 6° (–3/+14) in the femora and 7° (+3/+12) in the tibiae. Therefore, the physiological torsional tolerance of 15° 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.

Analyse der Beingeometrie – Standardtechniken und Normwerte

Summary. 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.Zusammenfassung. Die Diagnostik von posttraumatischen Deformitäten im Bereich der unteren Extremität umfaßt die Analyse der gesamte Beingeometrie. Die standardisierte klinische Untersuchung ist das erste Glied in der diagnostischen Kette, sie liefert wertvolle Hinweise für die anschließende bildgebende Diagnostik. Durch sie allein kann weder eine Fehlstellung ausreichend genau beschrieben, noch eine Indikation zur Operation gestellt werden. Die Diagnostik von Achsenabweichungen in der Frontal- und Sagittalebene erfolgt durch exakt eingestellte konventionelle radiologische Aufnahmen. Goldstandard zur Torsionswinkel- und Längenbestimmung ist die Computertomographie. Dennoch können die unterschiedlichen Methoden nur bedingt miteinander vergleichen werden. Nicht jede computertomographische Messung ist der klinischen Untersuchung überlegen. Der Nachweis der Reproduzierbarkeit und Genauigkeit ist für die Interpretation der Ergebnisse Voraussetzung. Normwerte wurden bisher nur für die Ulmer Methode publiziert. Die einzigen Vorteile der Kernspintomographie bei der Bestimmung der Beintorsion sind die fehlende Strahlenbelastung und die gute Darstellung von noch nicht vollständig verknöcherten Epiphysen bei Kindern im Vorschulalter. Ihre Genauigkeit und Reproduzierbarkeit ist jedoch der Computertomographie unterlegen. Fortschritte bei der sonographischen Bestimmung der Beingeometrie haben diese Vorteile relativiert. Die dreidimensionale sonographische Bestimmung der Beingeometrie hat einen festen Platz in der Diagnostik von Fehlstellungen bei Kindern und Jugendlichen eingenommen. Sie wird zunehmend auch zur präoperativen Planung bei Erwachsenen eingesetzt.

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.

Korrekturosteotomien des distalen Femur mit retrogradem Marknagel

ZusammenfassungDeformitäten des distalen Femur werden meist suprakondylär korrigiert. Die Osteotomie erfolgt hierbei “in klassischer Technik” mit der oszillierenden Säge, die Osteosynthese mittels Winkelplatte. Nachteile dieser Technik liegen zum einen im ausgedehnten Operationstrauma, zum anderen in der Beschränkung der räumlichen Korrekturoptionen.Die suprakondyläre Knochendurchtrennung mittels Domosteotomie bzw. Bohrlochosteoklasie und nachfolgender retrograder Marknagelung (RMN) bietet hierzu eine vielversprechende Alternative. An einem Kollektiv von 12 prospektiv erfassten Patienten mit mehrdimensionalen Deformitäten des distalen Femur werden erstmalig die Erfahrungen mit dieser minimal-invasiven Korrekturtechnik ausgewertet. Einzelheiten der räumlichen Analyse der Deformität, der Operationsplanung, der Korrekturtechnik und der Nachbehandlung werden angegeben.Bei allen Patienten erfolgte prä- und postoperativ eine Analyse der Beingeometrie sowie der Kniegelenksfunktion. 7 Korrekturen wurden einzeitig durchgeführt. In 5 Fällen schloss sich der suprakondylären Akutkorrektur eine Kallusdistraktion bzw. ein Segmenttransport über den RMN mittels unilateralem Distraktions-Fixateur externe an. Bei 11 Patienten wurde das präoperativ definierte Korrekturziel erreicht, in einem Fall war das Ausmaß der frontalen Korrektur ungenügend. Die funktionellen Ergebnisse waren insgesamt gut. Die knöcherne Heilung im Bereich der Osteotomien und des Distraktionskallus war zeitgerecht. Bei einem Patienten entwickelte sich 6 Monate nach Abschluss der Kallusdistraktion eine Markraumphlegmone, die nach vorzeitiger Metallentfernung ausheilte. Sonstige Komplikationen traten nicht auf.Die vorgestellte Operationstechnik ist planerisch und operativ anspruchsvoll, bietet andererseits eine wertvolle Alternative für die Korrektur komplexer suprakondylärer Femurdeformitäten.AbstractDeformities 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.

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.

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.Level of Evidence: Level IV Therapeutic Study. See the Guidelines for Authors for a complete description of levels of evidence.