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Using the retrieved devices from one autopsy and five reoperations, the biocompatibility of explanted Talent stent-grafts was investigated to highlight the capacity of the fabric to act as an effective scaffold to regenerate a blood conduit. The autopsy device was encapsulated both internally and externally, but the capsules did not penetrate through the fabric structure. The reoperation devices showed discrete patches of compact fibrin and irregularly scattered mural thrombi. Positive staining of α-actin, tissue plasminogen activator (tPA), urokinase (uPA), urokinase receptor (uPAR), and urokinase inhibitors (PAI 1, PAI 2, PAI 3, and protease nexin), and D-dimer was more frequently identified in the autopsy sample than in the reoperation samples. This preliminary assessment shows that the stent-graft retrieved during autopsy was better healed than those explanted at reoperation.

Hintergrund Der perkutane transdeltoidale Zugang zur Versorgung proximaler Frakturen des Humerus birgt das Risiko einer Lasion des N. axillaris. Ziel dieser Studie war die Erstellung eines „Risikoprofils“ einer Interferenz der Schraubenlocher mit dem N. axillaris fur insgesamt 6 winkelstabile Platten verschiedener Hersteller.

It is generally accepted that vessel cannulation is technically more difficult and results in more complications in neonates. A sound anatomical knowledge of the inguinal area is therefore important in the selection of appropriately sized central line catheters as well as the approach to central vessel access. Eleven stillborns were investigated. Birth weight (mean: 2,414 g, 900–4,100 g) and gestational age (mean 34 1/7 weeks', 27 6/7–42 1/7) varied within normal range. The outer diameters of the femoral artery (FA), femoral vein (FV), and great saphenous vein (GSV) were determined. The distance between the anterior superior iliac spine and the pubic tubercle was set as 100% and the vessel intersection points were calculated as percentage values of the inguinal ligament length, starting at the iliac spine. The FA has a diameter of 1.9 ± 0.5 mm without correlation to gestational age. The FA crosses the inguinal ligament centrally. The FV has a diameter of 3.1 ± 1.0 mm and does have correlation to gestational age. The FV crosses the inguinal ligament at 63–64%. The GSV has a diameter of 1.4 ± 0.7 mm. Its point of intersection at the level of the inguinal ligament is 68–70%. We conclude that cannulation of the femoral artery or vein should not be performed too far (

The mechanisms of injuries to the tibiofibular syndesmosis include isolated rupture and rupture in combination with ankle fractures. Current concepts of surgical treatment are fixation using bioabsorbable screws, syndesmotic stapling, syndesmotic hooks, and the widely used screw fixation. Postoperative care utilises passive motion of the ankle joint either with or without axial weight-bearing. The aim of our investigation was to quantify the motion of the mortise during axial load. Therefore, photoelastic tests, on the one hand, and biomechanical tests of cadaveric specimens, on the other, using axial loads of up to 2,000 N were used. Our photoelastic investigations showed force distribution through the screw into the cranial and caudal parts of the distal fibula. Biomechanical testing showed a progressive dehiscence in both ruptured and fixated specimens up to 2.89 (ruptured) and 2.42 mm (despite screw). Our findings strongly suggest a concept of partial weight-bearing at most to support regeneration of scar tissue and to prevent the appearance of instability in the ankle joint.

Lumbar spinal stenosis (LSS) with neurogenic intermittent claudication is one of the most common degenerative spinal diseases in the elderly. For patients over 65 years with LSS, open decompression is the most frequent spinal surgery. One problem associated with decompression surgery is the emergence of instability, which is found in varying grades of severity. For some patients with LSS, interspinous process devices (IPD) may be a viable alternative to open decompression. The purpose of this study is to examine the destruction and changes to the interspinous and supraspinous ligament complex after percutanous IPD implantation.Biomechanical and anatomic assessments were performed on the lumbar spine (L1-L4) of 11 fresh human cadavers. The biomechanical examination assayed the force necessary to disrupt the interspinous-supraspinous ligament complex without and after implantation of an IPD. For the anatomic examination, one lumbar spine was plastinated. Serial 4-mm thick sections were cut in sagittal and horizontal planes. The macroanatomic positioning of the implants was then analysed.Biomechanics: The average age of the cadavers was 80.6±10.2 years. The minimum average disrupting forces measured 313.74±113.44 N without and 239.47±63.64 N after IPD implantation, a significant (p0.018) decrease of an average 23.7%. Anatomy: After posterolateral percutaneous IPD implantation, the posterior third of the interspinous ligament, the supraspinous ligament, the thoracolumbar fascia and paraspinous muscles bordering the inter-/supraspinous ligament complex remained undamaged.The implantation of an interspinous "stand-alone" spacer significantly minimises the force necessary to disrupt the ISL/SSL complex. After posterolateral percutaneous IPD implantation, the thoracolumbar fascia and associated musculature, which act in synergy with the ISL/SSL complex to stabilise the vertebral column, remain intact.

Displaced tibial eminence fractures require surgical fixation in order to obtain a stable knee joint. Suture fixation with FiberWire(®) seems to be the most favorable therapeutic option. Biomechanical studies show failure of this technique most commonly due to a suture cutout with subsequent fracture of the tibial eminence fragment. The goal of this study is to compare the biomechanical properties of three different techniques of suture fixation using FiberWire(®).Bone mineral density was evaluated in 18 human knee specimens by pqCT, and three similar groups were formed. A standardized anterior tibial eminence fracture was created, and suture fixation was performed using one of three different techniques in 6 specimens each. Cyclic and destructive testing was conducted.Significant differences between the three techniques could be shown neither in the cycles needed to achieve a steady state nor in a failure load or initial stiffness. Almost all specimens failed by suture cutout.The presented modification of the existing technique for suture fixation of tibial eminence fractures did not lead to an increased initial stability nor did it lower the rate of suture cutout. All tested suture techniques showed comparable initial stiffness and failure load.

A tibial nail with fixed-angle locking screws intends to combine the advantages of angular stability and intramedullary stabilization in extraarticular proximal tibial fractures. The goal of this study is to analyze if the angle stable tibial nail (ASN) is biomechanically more stable than an established conventional standard nail (CN). Two types of nails were compared on a series of ten matched pairs of human tibiae. After setting a proximal tibial defect fracture, the intramedullary stabilized tibiae were axially loaded starting from 100 N increasing in steps of 100 N after every 200 cycles until failure was reached. Failure was defined as deformation of the fracture gap, fracturing of the bone or the implant. The two types of nails showed no significant difference in terms of maximum tolerated load, maximum cycles repeated or axial deformation of the bone–implant construct. The mean load at failure was 1,365 N for the CN and 1,195 N for the ASN. The mean axial deformation for conventional (19 mm) and angle stable nail (21 mm) did not differ significantly. Slightly less nail or screw loosening was noticed with the fixed-angle nail. No significant difference in stability between the two compared implants could be demonstrated. A trend could be shown indicating that the rate of nail loosening in the proximal osteotomized part of the bone was lower for the angle stable nail. This trend, however, could not be substantiated statistically.

Individual variations in the anatomy of the knee joint have been suggested to affect the ability to functionally compensate for ACL insufficiency or to put an individual at an increased risk of ACL injury. These variations include the posterior tibial slope, the concavity of the medial tibial plateau, the convexity of the lateral tibial plateau, and the configuration of the femoral condyles. This anatomical study investigates if there is a correlation between the individual surface geometry of the femorotibial joint and the morphometry of the ACL. These data were assumed to provide evidence whether or not the functional stability of an ACL-insufficient knee may be derived from its radiographic surface geometry. Standardised measurement techniques were used to analyse the surface geometry of 68 human cadaver knees. Data were correlated with the cross-sectional area, the area of insertion and position of the footprint of the ACL and its functional bundles. Analysis revealed that there was a significant, but weak correlation between the femoral and tibial area of ACL insertion and the depth of the medial and lateral femoral condyle. No correlation was found between the surface geometry of the femorotibial joint and the cross-sectional area of the ACL. The results of this anatomical study suggest that the relationship between the joint surfaces and the morphometry of the ACL primarily is a function of size of the knee joint. Based on our results, there is no evidence that the stability of the knee can be derived from its radiographic surface geometry.

Purpose: To identify the wrist tendon most effectively maintaining the trapezial space in interpositional arthroplasty in osteoarthritis of the carpometacarpal joint of the thumb.Methods: The morphometrics of the os trapezium and the tendons of the flexor carpi radialis, extensor carpi radialis longus, and abductor pollicis longus were determined. The stiffness and compressive loading characteristics of the rolled-up tendons were compared to the os trapezium.Results: No significant morphometric differences between the three tendons were found. The mass and volume of the trapezium was significantly larger when compared to the tendon balls. No significant differences in the compressive loading resistance were found between the tendons, but the mean stiffness was 85% lower when compared to the os trapezium.Conclusions: Neither tendon material approached the volume nor the stiffness provided by the os trapezium. Any tendon is considered to insufficiently maintain the trapezial space following trapeziectomy.

Muscle strain injuries are common in sports, and a high incidence is reported for the hamstring muscles, especially in the proximal region, where the long head of the biceps femoris muscle is most frequently affected. To look for some architectural peculiarities, which would make this muscle vulnerable, 101 legs of embalmed human cadavers were dissected and descriptively examined, morphometric data were obtained in the proximal region, and slices of plastinated specimens were microscopically examined. The 3 muscles composing the proximal hamstring complex are partly twisted around each other and possess common fibrous adhesions. Biceps femoris (BF) and semitendinosus (ST) muscles form a common head, to which the ST contributes the majority of fascicles extending 9 cm down from the ischiac tuberosity, thereby attaching to the common tendon at a remarkable pennation angle. The first BF fascicles origin from the common tendon only at 6 cm distance from the ischiac tuberosity. It is concluded that the high incidence of proximal BF strains may be a misinterpretation due to insufficient imaging and the complex architecture. It is suggested that the pennation angle at which the ST inserts to the common tendon makes this muscle especially vulnerable for strains during forced eccentric contractions.

Prazise Implantation von Oberflachenersatzprothesen der Hufte durch bildfreie Computernavigation. Vermeidung von Fehlimplantationen am Femurkopf, die ein fruhes Implantatversagen bedingen konnten. Koxarthrose bei normaler Knochendichte; geringe Deformitat des Huftkopfes, so dass ein Uberfrasen des Schenkelhalses ohne dessen Verletzung moglich ist. Osteoporose; ausgepragte Huftkopfnekrose; Nickelallergie; kleine Pfanne bei breitem Schenkelhals, so dass ein unnotiger azetabularer Knochenverlust entstehen wurde; aktuelle oder geplante Schwangerschaft, Stillzeit. Uber einen dorsalen Standardzugang Darstellung des Huftgelenks, bikortikales Einbringen einer Schanz-Schraube zur Aufnahme des Referenzsterns auf Hohe des Trochanter minor. Referenzieren der Epikondylen, aller vier Ebenen des Schenkelhalses und des Huftkopfes mit Navigationspointer; Planung der Implantatposition am steril bezogenen Bildschirm; navigiertes Einbohren eines Fuhrungsdrahts, navigierte Tiefenfrasung. Kanuliertes Uberfrasen des Huftkopfes. Konventionelle Implantation der Pfanne; anschliesend Zementieren der Femurkomponente mit hochviskosem Zement unter Vermeidung von Hammerschlagen. Verifikation der Implantatposition durch das Navigationssystem; Entfernung der Schanz-Schraube, Gelenkreposition und Wundverschluss in ublicher Weise. Mobilisation an zwei Unterarmgehstutzen mit 20 kg Teilbelastung fur 2 Wochen, Belastung mit halbem Korpergewicht bis zur 6. Woche, anschliesend Vollbelastung und Freigabe. Der Vergleich von 40 navigierten und 32 konventionell implantierten ASR®-Prothesen ergab eine signifikante Reduktion von Ausreisern durch die Computernavigation (navigiert: ein Ausreiser, konventionell: neun Ausreiser; p < 0,001). Zwischen geplanter und verifizierter, navigierter Implantatposition wurden eine Abweichung des CCD-Winkels von 1° sowie eine Differenz der Antetorsion von 1° und des Offsets von 1,5 mm gemessen. Eine weiterfuhrende computertomographiebasierte anatomische Studie konnte eine Genauigkeit des Navigationssystems in der Frontalebene von 1° nachweisen.

Comparing five commercially-available miniscrew types for skeletal anchorage with regard to the biomechanical properties influencing their primary stability.Included in this study was a total of 196 self-tapping and self-drilling miniscrews having a diameter of 2 mm (or the largest possible diameter of the manufacturer in question), a thread shaft length of 10 mm, or the longest miniscrew supplied by the manufacturers. The screw types tested were the FAMI 2, Orlus mini-implant, T.I.T.A.N. Pin, tomas-pin and Vector TAS. Insertion and loosening torque measurements, and pullout tests in axial (0 degrees), 20 degrees and 40 degrees directions, as well as test series with and without pilot hole drilling were performed. Bovine femoral heads having the same bone mineral density (BMD) were used as bone-testing material.Higher insertion torques were found for the cylindrical FAMI 2 screw, the conical Orlus mini-implant and the Vector TAS screw (with mean values of 39.2 Ncm, 32.1 Ncm and 49.5 Ncm) than for the cylindrical T.I.T.A.N. pin and tomas-pin. Insertion without predrilling led the insertion torques of all five screws to rise significantly. We noted statistically significant differences among the five screws in the pullout tests. Those highly significant differences at axial (0 degrees) and 20 degrees angles were not apparent at the 40 degrees pullout angle. Compared with the pullout forces (load) in the axial direction, the cylindrical screws' load values decreased markedly according to the angle (by up to -46.6%). The reduction in pullout force in conjunction with an increasing angle was much less pronounced in the conical screws (-0.8% to -29.0%). The tomas-pin demonstrated the highest pullout force and stiffness values throughout the tests. A total of five tomas-pins, two Orlus mini-implants and one FAMI 2 screw fractured during the pullout tests.Results from our insertion torque measurements suggest that a conical screw design will provide greater primary stability than cylindrical screw types. The cylindrical screw design's superiority was evident in the pullout tests. All the miniscrews' primary stability rose after drill-free insertion. The tomas-pin screws, although biomechanically superior to the other screws, were most prone to fracture.

Zusammenfassung Bursen unterstutzen die Form des Fuses und des Sprunggelenkes durch ihre Polsterfunktion zwischen Knochen und Haut, zwischen Knochen untereinander oder zwischen Knochen und Sehnen. Im Ubersichtsartikel wird neben dem Forschungsuberblick uber die in der Literatur der letzten 200 Jahre beschriebenen Bursen und einer Definition des Begriffes Bursa synovialis die Entwicklungsgeschichte und Histologie der Bursen dargelegt und eine einheitliche Beschreibung der Bursen des Fuses und des Sprunggelenkes in Anlehnung an die Regeln der Nomina Anatomica vorgestellt.

Purpose This study investigates the influence of various femoral anterior cruciate ligament graft fixation methods on the amount of tension degradation and the initial fixation strength after cyclic flexion-extension loading in a porcine knee model. Methods One hundred twenty porcine digital extensor tendons, used as 4-stranded free tendon grafts, were fixated within porcine femoral bone tunnels by use of extracortical button, cross-pin, or interference screw fixation. One hundred twenty porcine patellar tendon–bone grafts were fixated by use of cross-pin, interference screw, or press-fit fixation. Each femur-graft complex was submitted to cyclic flexion-extension loading for 1,000 cycles throughout different loading ranges, and the total loss of tension was determined. After cyclic testing, the grafts were loaded to failure, and the data were compared with a pullout series without cyclic loading. Results Tension degradation after 1,000 cycles of flexion-extension loading averaged 62.6% ± 10.0% in free tendon grafts and 48.9% ± 13.35% in patellar tendon–bone grafts. There was no influence of the loading range on the total amount of tension degradation. The total amount of tension degradation was the highest with interference screw fixation of free tendon and patellar tendon–bone grafts. Despite excessive loss of tension, the initial fixation strength of the femur-graft complex was not reduced. Conclusions The method of femoral graft fixation significantly influenced tension degradation during dynamic flexion-extension loading. Femoral graft fixation methods that secure the graft close to the tunnel entrance and that displace the graft substance from the center of the bone tunnel show the largest amount of tension degradation during cyclic flexion-extension loading. The graft substance, not the fixation site, was the weakest link of the graft complex within this investigation. Clinical Relevance We believe that the graft fixation method should be considered when aiming to improve the precision of femoral graft placement in anterior cruciate ligament reconstruction.

The existing studies concerning image-free navigated implantation of hip resurfacing arthroplasty are based on analysis of the accuracy of conventional biplane radiography. Studies have shown that these measurements in biplane radiography are imprecise and that precision is improved by use of three-dimensional (3D) computer tomography (CT) scans. To date, the accuracy of image-free navigation devices for hip resurfacing has not been investigated using CT scans, and anteversion accuracy has not been assessed at all. Furthermore, no study has tested the reliability of the navigation software concerning the automatically calculated implant position. The purpose of our study was to analyze the accuracy of varus-valgus and anteversion using an image-free hip resurfacing navigation device. The reliability of the software-calculated implant position was also determined.A total of 32 femoral hip resurfacing components were implanted on embalmed human femors using an image-free navigation device. In all, 16 prostheses were implanted with the proposed position generated by the navigation software; the 16 prostheses were inserted in an optimized valgus position. A 3D CT scan was undertaken before and after operation.The difference between the measured and planned varus-valgus angle averaged 1 degrees (mean +/- SD: group I, 1 degrees +/- 2 degrees ; group II, 1 degrees +/- 1 degrees ). The mean +/- SD difference between femoral neck anteversion and anteversion of the implant was 4 degrees (group I, 4 degrees +/- 4 degrees ; group II, 4 degrees +/- 3 degrees ). The software-calculated implant position differed 7 degrees +/- 8 degrees from the measured neck-shaft angle. These measured accuracies did not differ significantly between the two groups.Our study proved the high accuracy of the navigation device concerning the most important biomechanical factor: the varus-valgus angle. The software calculation of the proposed implant position has been shown to be inaccurate and needs improvement. Hence, manual adjustment of the implant position in the software-planning step is frequently required.

Summary Objectives: Thoracostomy tubes are widely used in neonatology. Complications occurred significantly more frequently in infants, especially neonates, than in adults. Principally, the access is the modified Buelau position which takes place in the anterior axillary line at the 4th or 5th intercostal space above the margin of the ribs. Aim: This study seeks to determine the characteristics and topographic conditions of the anatomical structures at the ventral and lateral thoracic wall in the preterm and term neonate. Background: Fifteen formalin-fixed stillborns were prepared (nine male, six female, 28–43 weeks gestational age). Methods/Materials: The anatomical preparation involved the complete thoracic wall region. Results: In all preparations, a venous vessel was detected at the lateral wall and was identified as v. thoracoepigastrica without accompanying artery. Arteria (a.) and vena (v.) thoracica interna were regularly found close to the sternal plate on both sides between rib and fascia. With increasing gestational ages the course of the v. thoracoepigastrica varied significantly between the left and right thoracic wall. It was demonstrated that the v. thoracoepigastrica regularly arose within the abdominal or thoracic subcutaneous fat and drained into the v. subclavia. The variance between its course was almost 5–12 mm to the lateral or medial side. At both thoracic sides, no other organs or organ structures except lung parenchyma could be detected when using the Buelau position. Conclusions: The anterior to midaxillary line between the 4th or 5th intercostal space (Buelau position) is safe for the use of thoracostomy tubes in preterm and term infants.

Today the most frequently used operative procedures in advanced arthritis of the hindfoot joints are isolated talonavicular arthrodesis and double arthrodesis (involving the talonavicular and calcaneocuboid joints, i.e. the Chopart joint). This in vitro study investigates whether the fusion of the talonavicular joint alone can provide the hindfoot, as well as a midfoot, with comparable biomechanical stability as the double arthrodesis does. Hence with the less-invasive intervention the same benefit in terms of pain reduction and better functionality could be achieved. In a series of ten fresh cadaver feet without any radiological pathologies, we measured the range of motion of different tarsal bones in three planes under axial stress. Every foot was loaded without arthrodesis, after talonavicular and after double arthrodesis, by charging tibia and fibula with a force of 350 N using a calibrated Instron® load frame. Each tarsal bone was marked with a K-wire and its motion was measured by registering the movement of the wire’s shade that was projected onto the surrounding walls of the trial box. Both operative procedures led to a considerable reduction of the motion of every marked bone to a mean of 18% of the preoperative value. In direct comparison of the two simulated arthrodeses we found for every bone and in every plane only minimal differences of the mean excursions of 1.0 mm on average. Both fusions lead to equal residual tarsal bone motion postoperatively, and provide the midtarsal joint as well as the subtalar joint with comparable biomechanical stability. Isolated talonavicular arthrodesis is a useful and effective alternative to double arthrodesis. It is the less complicated, less-invasive and functionally equivalent operative option for arthritic alterations of the hindfoot and transverse tarsal joint.

The aim of our study was to investigate whether placing of the femoral component of a hip resurfacing in valgus protected against spontaneous fracture of the femoral neck. We performed a hip resurfacing in 20 pairs of embalmed femora. The femoral component was implanted at the natural neck-shaft angle in the left femur and with a 10° valgus angle on the right. The bone mineral density of each femur was measured and CT was performed. Each femur was evaluated in a materials testing machine using increasing cyclical loads. In specimens with good bone quality, the 10° valgus placement of the femoral component had a protective effect against fractures of the femoral neck. An adverse effect was detected in osteoporotic specimens. When resurfacing the hip a valgus position of the femoral component should be achieved in order to prevent fracture of the femoral neck. Patient selection remains absolutely imperative. In borderline cases, measurement of bone mineral density may be indicated.

Purpose The present study aimed at summarizing and presenting the anomalous muscles that a surgeon might encounter during axillary lymphadenectomy (AL). Methods For this purpose, both the anatomical and surgical literature was reviewed and an anatomical study on 107 cadavers was carried out. Furthermore, based on the anatomical features of the anomalous muscles that came up during our study and taking into consideration the landmarks of the AL, we further analyzed the complications that may arise from each of these muscles, along with their preoperative and intraoperative recognition and management. Results The literature review revealed that there are three supernumerary muscles that may affect the AL, namely the Langer's axillary arch, the pectoralis quartus and the chondroepitrochlearis muscles, as well as the aplasia of the lower part of the pectoralis major muscle. Eight out of the 107 (7.48%) cadavers that we dissected had such an abnormal muscle in the axilla. Specifically, the axillary arch was found unilaterally in five cadavers (4.67%) and the pectoralis quartus muscle was present unilaterally in three cadavers (2.8%). One cadaver had both an axillary arch and a pectoralis quartus muscle in the right side. The abdominal and almost the whole sternocostal portion of the pectoralis major as well the pectoralis minor muscle were absent in one cadaver (0.93%). The chondroepitrochlearis muscle was not found in any of the cadavers that we dissected. Conclusions The present study offers the necessary preoperative knowledge for recognizing these muscles during AL, avoiding thus the complications that may arise from them.

Objectives: Dental implants are widely used nowadays in single-tooth loss or for anchoring a dental prosthesis. For a long standing the implant must be sufficiently osseointegrated. In anatomical specimens are to find increasingly dental implants which are useful to investigate. Methods: Microradiographic and histological analyses were performed on 17 dental screw-type implants deriving from the mandibulae of five anatomical specimens aged from 69 to 87 years. For three individuals data were available by inquiring the relatives: implantation was 11, 10 and 7 years before death. One of the three cases was a tumor patient. The interforaminal part of the mandibula was resected 7 years before death and replaced by an iliac crest autograft, into which four implants had been inserted some time later. Each of the 17 implants was isolated by cutting the mandible into bone blocks. After embedding, cutting and grinding the sections were x-rayed and stained. Results: With exception of the tumor patient, in all cases an intimate contact between compact and/or cancellous bone and implants was given. No translucent lines between bone and implant were detectable by microradiography. The threads and interspaces of the implants were in contact with mineralized, new compact bone, or spongy trabeculae reached the implants surface rectangulary. Bone resorption phenomena were observed in the crestal area only. Conclusion: The results show that functional loading for even more than ten years is the basis for biomechanical integration of dental implants. Continuous bone remodeling seems to guarantee implant stabilisation independent from age.

Correct placement of the tibial and femoral bone tunnel is prerequisite to a successful anterior cruciate ligament (ACL) reconstruction. This study compares the resulting radiographic femoral bone tunnel position of two commonly used techniques for arthroscopically assisted drilling of the femoral bone tunnel: the transtibial approach or drilling through the anteromedial arthroscopy portal. The resulting bone tunnel position was assessed in postoperative knee radiographs of 70 patients after ACL reconstruction. Three independent observers identified the femoral bone tunnel and determined its position in the lateral and A-P view. Differences in femoral tunnel position between transtibial and anteromedial drilling were evaluated. In the sagittal plane, significantly more femoral bone tunnels were positioned close to the reference value using an anteromedial drilling technique (86%) when compared to transtibial drilling (57%). Drilling through the transtibial tunnel resulted in a significantly more anterior position of the femoral tunnel. In the frontal plane, femoral bone tunnels which were placed through the anteromedial arthroscopy portal displayed a significantly greater angulation towards the lateral condylar cortex (50.92 degrees ) when compared to transtibial drilling (58.82 degrees ). In conclusion, drilling the femoral tunnel through the anteromedial arthroscopy portal results in a radiographic femoral bone tunnel position which is suggested to allow stabilization of both anterior tibial translation and rotational instability when using a single bundle reconstruction technique. Further studies may evaluate if there are any clinical advantages using the anteromedial portal technique.

This study compared four miniscrew types for skeletal anchorage (Aarhus, FAMI, Dual Top and Spider) regarding their biomechanical properties contributing to primary stability. Insertion torque measurements and pull-out tests in axial (0 degrees ) as well as in the 20 degrees and 40 degrees direction were performed. Stiffness of the screw-bone construct was calculated from the load-displacement curve. Conic FAMI and Dual Top screws had higher insertion torques. Insertion torques were raised by drill-free insertion of FAMI and Dual Top screws. Statistically significant differences were found between the 4 screw types in pull-out tests. The highly significant differences between the four screws for peak load in the axial (0 degrees ) and 20 degrees direction were not apparent in 40 degrees angular loads. For the conical screws, peak load values increased in angular compared with axial load. The Dual Top screw achieved the highest values for peak load and stiffness. 12 Dual Top and 1 Spider screw heads fractured in the pull-out tests. A conical drill-free screw design achieves higher primary stability compared with cylindrical self-tapping screws. This effect was more obvious in insertion torque estimations rather than in pull-out tests. The Dual Top screws, although biomechanically superior to other screw types, were most prone to fractures.

Zusammenfassung Es wird die arterielle extra- und intraossare Gefasversorgung der Ossa metatarsi im Bereich der Basis, des Schaftes und des Kopfes untersucht und in Bezug auf vorfuschirurgische Eingriffe ausgewertet. Die Basen werden uber plantare und dorsale Arterien versorgt. Der Schaft der Ossa metatarsi wird uber eine A. nutricia und uber ein periostales Gefasgeflecht versorgt. Die Hauptversorgung des Kopfes des Os metatarsi I erfolgt von plantar. Arterielle Zuflusse zu den Ossa metatarsi II–V erfolgen von plantar und dorsal. An drei Praparaten werden insgesamt funf vorfuschirurgische Eingriffe vorgenommen und im Anschluss die Beeintrachtigung der arteriellen Versorgung untersucht. Bei allen Praparaten werden Gefasverletzungen festgestellt. Diese werden in Zusammenhang mit den Operationen ausgewertet.

The purpose of this study was to develop a two-dimensional density distribution pattern of the subchondral cortical bone of the radial head using subtraction densitometry. The bone density of 32 normal specimens and five with macroscopic signs of osteoarthritis was measured before and after milling off the cortical bone surface. Electronic subtraction gave the density of the subchondral cortical bone. Twenty-one specimens had areas of high bone density in the ulnar-dorsal area, five specimens showed a ventral and ulnar density maximum and six had a density maximum in the center of the radial head joint surface. No density maximum was seen in the lateral part of the joint surface. The density maximum shifted towards the dorsal-ulnar part of the radial head with decreasing total subchondral bone density. Osteoarthritic radial heads had the same distribution as non-arthritic specimens. Eccentric subchondral bone density reflects eccentric radiohumeral force transmission. This could be a reason for development of radiohumeral arthritis or the failure of radial head prostheses. Bone density patterns correlate with the incidence of radial head fractures and fracture line may be positioned between areas of high and low densities.

Purpose: To determine whether or not suturing a soft tissue graft in a whipstitch fashion is an essential procedure in order to ensure sufficient initial fixation strength of the cross-pin fixation technique in anterior cruciate ligament reconstruction. Methods: Porcine digital extensor tendons were used as 4-stranded soft tissue grafts. Specimens were fixated within 52 porcine femoral bone tunnels using a cross-pin fixation technique (RigidFix; Ethicon, Norderstedt, Germany). In group I (n = 28), the looped-over part of the grafts was sutured using a whipstitch technique; in group II (n = 28) the grafts were not sutured. Initial fixation properties were determined using either a single cycle load to failure protocol or a dynamic loading protocol, submitting the graft to 1,000 cycles of flexion–extension loading between 0° and 90°, followed by ultimate loading to failure. The graft–pin interaction and the graft–tunnel interface was histomorphologically visualized in unloaded and dynamically loaded grafts. Results: After dynamic loading, the residual displacement in sutured grafts was lower when compared to nonsutured grafts. The ultimate failure loads were significantly lower in nonsutured grafts when compared to sutured grafts after dynamic loading. The histomorphologic analysis demonstrated intratunnel displacement of nonsutured grafts after dynamic loading, while sutured grafts remained in situ. In cases where the cross-pins had not threaded the tendon loops, sutured grafts provided higher fixation strength and less graft displacement. Conclusions: The results of the present study suggest that suturing the looped-over portion of a quadruple tendon graft provides superior biomechanical graft fixation properties when compared to nonsutured grafts when using the femoral cross-pin fixation technique. Clinical Relevance: Suturing the hamstring tendon graft in a whipstitch fashion is recommended for the femoral cross-pin fixation of an anterior cruciate ligament graft.

We have evaluated four different fixation techniques for the reconstruction of a standard Mason type-III fracture of the radial head in a sawbone model. The outcome measurements were the quality of the reduction, and stability. A total of 96 fractures was created. Six surgeons were involved in the study and each reconstructed 16 fractures with 1.6 mm fine-threaded wires (Fragment Fixation System (FFS)), T-miniplates, 2 mm miniscrews and 2 mm Kirschner (K-) wires; four fractures being allocated to each method using a standard reconstruction procedure. The quality of the reduction was measured after definitive fixation. Biomechanical testing was performed using a transverse plane shear load in two directions to the implants (parallel and perpendicular) with respect to ultimate failure load and displacement at 50 N. A significantly better quality of reduction was achieved using the FFS wires (Tukey’s post hoc tests, p < 0.001) than with the other devices with a mean step in the articular surface and the radial neck of 1.04 mm (sd 0.96) for the FFS, 4.25 mm (sd 1.29) for the miniplates, 2.21 mm (sd 1.06) for the miniscrews and 2.54 mm (sd 0.98) for the K-wires. The quality of reduction was similar for K-wires and miniscrews, but poor for miniplates. The ultimate failure load was similar for the FFS wires (parallel, 196.8 N (sd 46.8), perpendicular, 212.5 N (sd 25.6)), miniscrews (parallel, 211.8 N (sd 47.9), perpendicular, 208.0 N (sd 65.9)) and K-wires (parallel, 200.4 N (sd 54.5), perpendicular, 165.2 N (sd 37.9)), but significantly worse (Tukey’s post hoc tests, p < 0.001) for the miniplates (parallel, 101.6 N (sd 43.1), perpendicular, 122.7 N (sd 40.7)). There was a significant difference in the displacement at 50 N for the miniplate (parallel, 4.8 mm (sd 2.8), perpendicular, 4.8 mm (sd 1.7)) vs FFS (parallel, 2.1 mm (sd 0.8), perpendicular, 1.9 mm (sd 0.7)), miniscrews (parallel, 1.8 mm (sd 0.5), perpendicular, 2.3 mm (sd 0.8)) and K-wires (parallel, 2.2 mm (sd 1.8), perpendicular, 2.4 mm (sd 0.7; Tukey’s post hoc tests, p < 0.001)). The fixation of a standard Mason type-III fracture in a sawbone model using the FFS system provides a better quality of reduction than that when using conventional techniques. There was a significantly better stability using FFS implants, miniscrews and K-wires than when using miniplates.

Background: Although the anatomy and physiology of the venous circulation of the ankle and midfoot are well documented, the physiologic importance of forefoot mobility has not been reported in the literature. The question of this study was whether the first metatarsophalangeal (MTP) joint may operate, like the ankle, as a “pump” to encourage venous return. Methods: Forty-nine cadaver foot specimens were examined using dissection, plastination, vessel infiltration, and maceration, and radiographic (including venography, MRI, and magnetic resonance angiography) techniques. The anatomy and physiology were described and compared to the ankle joint. Forty patients had biphasic Doppler flow studies. Results: The major finding was the medial drainage of the plantar venous sinus, which is fibrotically bound to the joint capsule. Functional venous valves were evident distally and within fibrous vascular lumens. Mobilization of the first MTP joint led to compression and emptying of the veins. Passive mobilization of the first MTP joint led to an average flow increase of 55% ± 7 ( p < 0.0001), while active movement led to an average increase of 78% ± 7 ( p < 0.0001). Conclusions: Our described connection between the joint capsule and veins indicates a “toe-ankle pump” with a significant increase of venous blood flow during motion of the MTP joint. Possible clinical applications for an external MTP pump include anti-edema or thromboprophylactic therapy, especially in patients with foot or ankle injuries. A new toe-pump has been designed based on these results.

Neutral sphingomyelinase SMPD3 (nSMase2), a sphingomyelin phosphodiesterase, resides in the Golgi apparatus and is ubiquitously expressed. Gene ablation of smpd3 causes a generalized prolongation of the cell cycle that leads to late embryonic and juvenile hypoplasia because of the SMPD3 deficiency in hypothalamic neurosecretory neurons. We show here that this novel form of combined pituitary hormone deficiency is characterized by the perturbation of the hypothalamus-pituitary growth axis, associated with retarded chondrocyte development and enchondral ossification in the epiphyseal growth plate. To study the contribution by combined pituitary hormone deficiency and by the local SMPD3 deficiency in the epiphyseal growth plate to the skeletal phenotype, we introduced the full-length smpd3 cDNA transgene under the control of the chondrocyte-specific promoter Col2a1. A complete rescue of the smpd3(-/-) mouse from severe short-limbed skeletal dysplasia was achieved. The smpd3(-/-) mouse shares its dwarf and chondrodysplasia phenotype with the most common form of human achondrodysplasia, linked to the fibroblast-growth-factor receptor 3 locus, not linked to deficits in the hypothalamic-pituitary epiphyseal growth plate axis. The rescue of smpd3 in vivo has implications for future research into dwarfism and, particularly, growth and development of the skeletal system and for current screening and future treatment of combined dwarfism and chondrodysplasia.

The purpose of this study was to describe the anatomy of the intramedullary canal of the radial neck for stem design of radial head prostheses.Radial neck measurement was performed from the proximal edge of the radial tuberosity to the distal border of the articular surface on 40 macerated proximal radii using X-rays and Optosil imprints of the intramedullary canal. Radial neck to shaft angle was measured under image intensification.The neck length was 13.3 mm (range 8.0-20.0 mm) measured on X-rays and 13.5 mm (range 9.9-18.8 mm) on Optosil imprints. Concerning the neck's intramedullary canal we obtained a minimum diameter of 9.7 mm (range 6.3-16.4 mm) on X-ray. Corresponding Optosil imprints had a mean diameter of 11.6 mm (range 6.6-18.6 mm) at their proximal end, 10.5 mm (range 5.5-16.3 mm) in the middle and a minimum of 9.8 mm (range 6.0-16.9 mm) at the distal end. Differences between left and right sides were not significant between X-ray and Optosil imprints, nor between left X-ray and right imprints and vice versa at a P-level of 0.001. Radial neck to shaft angle was 167.8 degrees (range 160.5-178 degrees ) measured under image intensification at a rotation angle of 58.6 degrees (range 50-70 degrees ) supination.Geometry of the radial neck's intramedullary canal has been described for stem design. The minimum diameter was seen at the distal end, just proximal to the radial tuberosity. A forearm rotation of 58.6 degrees to full supination should be considered during implantation of monopolar prostheses. The wide variety of lengths and diameters complicates standard prosthetic design, but ipsilateral and contralateral X-rays can be useful for preoperative stem size calculation.

Objectives: Measurement of bone mineral density (BMD) is used frequently for assessment of bone strength and prediction of fracture risk in clinical settings. Among the bones in feet, fractures are seen often in second and third metatarsal of active sportsmen. This study was carried out to evaluate the reasons of increased risk of stress fractures in feet of active sportsmen by determining the BMD in overused regions.Methods: Two groups were examined in the present study. First group included males who were not sportsmen while the second and third groups were formed by professional male soccer and basketball players respectively. Areal bone density was measured by dual energy x-ray absorptiometry and the BMD values were calculated by using the rectangular region of interest in metatarsals.Results: The first metatarsal had the highest BMD in all groups (P

The purpose of this study was to correlate the four types of acromial shape with the existence of enthesophytes, which together comprise two important parameters for subacromial impingement syndrome and rotator cuff tears. In addition, a review of the literature was carried out. Four hundred twenty-three dried scapulas were studied at the Department of Anatomy in the University of Cologne, Germany. Four types of acromion were found: the three classical ones as described by Bigliani et al. ([1986] Orthop Trans 10:216) and a fourth one, where the middle third of the undersurface of acromion was convex (Gagey et al. [1993] Surg Radiol Anat 15:63–70). The correlation between the four types of acromion and the presence of enthesophytes at its anterior undersurface was also recorded. The distribution of acromial types was as follows: type I, flat, 51 (12.1%); type II, curved, 239 (56.5%); type III, hooked, 122 (28.8%); and type IV, convex, 11 (2.6%). Enthesophytes were found in 1 of type I (2%), in 19 of type II (7.9%), in 46 of type III (37.7%), and in 0 (0%) of type IV acromions. Overall, 66 (15.6%) out of 423 scapulas had enthesophytes. In all cases, they were localized at the site of the coracoacromial ligament insertion on the acromion. Enthesophytes were significantly (P < 0.05) more common in type III acromions and this combination is particularly associated with subacromial impingement syndrome and rotator cuff tears. In type I and in type IV acromions, the incidence of enthesophytes is very small and, according to other studies, with these two acromial types rotator cuff tears are also rare. Clin Anat. 20:267–272, 2007. © 2006 Wiley-Liss, Inc.

The anatomical relationships of the greater occipital nerve (GON) to the semispinalis capitis muscle (SCM) and the trapezius muscle aponeurosis (TMA) were examined to identify topographic landmarks for use in anesthetic blockade of the GON in occipital neuralgia. The course and the diameter of the GON were studied in 40 cadavers (29 females, 11 males), and the points where it pierced the SCM and the TMA were identified. The course of the GON did not differ between males and females. A left–right difference was detected in the site of the GON in the TMA region but not in the SCM region. The nerve became wider towards the periphery. This may be relevant to entrapment of the nerve in the development of occipital neuralgia. In three cases, the GON split into two branches before piercing the TMA and reunited after having passed the TMA, and it pierced the obliquus capitis inferior muscle in another three cases. The GON and the lesser occipital nerve reunited at the level of the occiput in 80% of the specimens. The occiput and the nuchal midline are useful topographic landmarks to guide anesthetic blockade of the GON for diagnosis and therapy of occipital neuralgia. The infiltration is probably best aimed at the site where the SCM is pierced by the GON. Clin. Anat. 19:332–336, 2006. © 2005 Wiley-Liss, Inc.

Introduction: Press-fit fixation of bone-patellar tendon–bone (BPTB) grafts in anterior cruciate ligament (ACL) reconstruction has been analyzed biomechanically in previous studies; however, the use of quadriceps tendon–patellar bone (QTPB) grafts has not been studied so far. It is hypothesized that QTPB grafts provide primary fixation strength comparable to BPTB grafts in press-fit ACL reconstruction with respect to bone plug length and loading angle. Materials and methods: Fifty-two QTPB grafts were harvested from fresh human cadaver knees (mean age 73.3 years) with the length of the patellar bone plug being either 15 mm (Group I) or 25 mm (Group II). The grafts were anchored within fresh porcine femora (mean age 12 months) using a press-fit fixation technique. Forty-eight specimens were loaded to failure at 10 mm/s with varying loading angles of 0°, 30°, and 60° until failure. A microradiographic pre–post-implantation analysis was conducted on four grafts. Results: The biomechanical testing showed a significant difference in the ultimate failure loads comparing Group I (mean 224±79.3 N) to Group II (mean 339±61.4 N), both showing mean ultimate failure loads to increase with rising loading angle. The predominant mode of failure was graft pullout at axial loading and tendon rupture at 60° loading angle. The microradiographic analysis revealed an iatrogenic damage of the bone–tendon junction on the cancellous aspect of the bone plug in all trials, corresponding with the site of impactor placement during implantation. Conclusion: QTPB grafts provide a loading capability comparable to BPTB grafts in press-fit ACL reconstruction. The broad and profound area of quadriceps tendon attachment to the patellar bone plug makes graft implantation demanding.

Eighteen patients with intraarticular calcaneal fractures treated with open reduction and internal fixation and augmentation with an injectable carbonated apatite cement. Functional follow-up studies using the Zwipp Foot Score and densitometry were performed at 6-month intervals postoperatively. Histological samples of biopsies obtained at the time of hardware removal (6 months postoperatively) were also analyzed. The use of bone cement led to intermediate-term functional outcomes that were no better than those reported with conventional surgical procedures using bone graft. Patients demonstrated postoperative difficulties similar to those seen in other studies of this fracture, including pain, subtalar motion restrictions, peroneal impingement, and difficulties on uneven terrain and with toe- and heel-walking. However, compared to patients treated surgically without injectable carbonated apatite cement, full weight bearing on the affected extremity was regained at an average 4 weeks postoperatively. In addition, autogenous bone graft was not required to fill the osseous defect using this technique, minimizing morbidity and discomfort. During the present observation period of 3 years, only a slight decrease in the density of the peripheral zones of the cement block was observed. Histological examination revealed fibrous bone formation resulting from remodelling processes. Complete resorption and remodeling of the bone cement were not complete at 3 years. One patient developed a postoperative wound infection. Another displayed cement loosening secondary to failure of bony ingrowth.

The present study was conducted to evaluate the influence of bone-plug length on the primary stability of patellar tendon-bone grafts, using a femoral press-fit fixation technique. Forty-eight human PTB grafts with a patellar bone-plug length of 15 mm and 25 mm were obtained from 24 human cadavers (mean age 72 years) and implanted to porcine femora in a press-fit fixation technique. Tensile loading was performed at 10 mm/s until failure at varying loading angles of 0 degrees, 30 degrees and 60 degrees. Compared to 25 mm, a significant decrease of primary graft stability was recorded in the testing of 15-mm bone plugs. For both plug lengths, the ultimate load to failure increased with rising the loading angles. While axial graft loading exclusively caused plug dislocation, the predominant mode of failure was tendon rupture at 60 degrees loading angle. We conclude that 15-mm bone plugs do not result in a sufficient stability for early aggressive rehabilitation and therefore 25-mm bone plugs are recommended for the femoral press-fit technique.

Bone vascularisation has gained increased interest in relation to the blood supply of bone fragments during treatment of fractures. In the current study the pattern of vascular supply of the proximal humerus was studied in six cadavers by the corrosion technique. Furthermore, the effect of fractures on the vascular supply was also investigated. In all preparations the intraosseous arteries of the humeral head arose from the circumflex arteries, which surrounded the humerus and dispatched branches towards the proximal end. The main vessel was the branch of the anterior circumflex artery, penetrating the major tubercle in six of six cases. Due to the intraosseous arch shape of this vessel it is referred to as the arcuate artery. Besides other smaller vessels, there was also a vascular network arising from the posterior circumflex artery. Their branches penetrated medially at the cartilage bone interface in five of six preparations. The medial bone arteries appear to gain distinctive importance in humeral head fractures by their impact on the vascularisation of the fracture fragments. After disruption of the arterial supply from the arcuate artery, the vascularisation of the head fragments is most likely ensured by this group of vessels. Therefore, necessary repositioning manoeuvres during open reduction of the fracture should be conducted with care in order to preserve these arteries.

We described the anatomy of the utero-ovarian venous system in the adult postmenopausal female cadaver using casts and the von Hagen's plastination technique. To qualitatively and quantitatively evaluate the uterine vein, the utero-ovarian arcade, the ovarian vein and the ramus communicans between left and right parametrium, we injected epoxy resin into the internal iliac vein and artery and the ovarian vein and artery in six cadavers. In two cases the internal genital organs were excised before injection and in the other four after the injection and polymerization of the resin. All specimens were macroscopically examined and venous diameters were digitally measured, the average values of the measured diameters being 3.38 mm for the uterine vein, 3.71 mm for the utero-ovarian arcade, 3.49 mm for the ovarian vein, and 3.71 mm for the ramus communicans. The veins were completely filled out and could be best examined in the four cases where in situ injection was performed. We could observe that the utero-ovarian arcade is an important vein with a caliber similar to that of the ovarian and uterine veins, that there is an impressive network of venous anastomoses between the left and right parametrium and that the fallopian tubes are drained by three separate veins: internal, median, and external tubal veins. Pelvic venous congestion was present in two specimens; in one of them it was located in the region of the left uterine vein and in the other one in the region of the left ovarian vein. Given the similar average diameters of the uterine vein, ovarian vein, and utero-ovarian arcade, we assume that there is no preferential uterine or ovarian venous drainage and that the veins of the internal genital organs are behaving like a venous pool. Nevertheless, congestion can affect limited sites, which can and should be treated locally.

Zusammenfassung Eine neue Methode zur Behandlung dieser lokalen Knorpelschaden im Bereich der Talusrolle stellt die autologe osteochondrale Transplantation, die auch „Mosaikplastik” genannt wird, dar. Hierbei werden kleine, zylinderformige Knorpel-Transplantate aus dem distalen Femur entnommen und am ladierten Bereich der Talusgelenkflache eingesetzt. In der vorliegenden Arbeit wird untersucht, in welchen Bereichen die Knorpeldicke sowie die Krummung der Gelenkflachen beider Skelettelemente annahernd gleich sind, um eine moglichst optimale Transplantation zu erzielen. Die Untersuchungsergebnisse zeigen, dass hinsichtlich gleicher Knorpeldicke und Krummungsradius nur punktuelle Ubereinstimmungen auftreten. Als besonders problematisch erwies sich die Tatsache, dass sich an der Talusrolle in weiten, vor allem den zentralen Bereichen ein derart hoher Krummungsradius findet, der beim Femur analog nicht vorkommt. Bei Knorpellasionen in diesen Bereichen am Talus scheint das Kriterium der Krummung einer optimalen Transplantation nicht gerecht werden zu konnen. Nach Auswertung der Messergebnisse scheint eine Lasion in den proximalen und distalen Bereichen des Talus mit einer Transplantatentnahme in den superioren und inferioren Bereichen des Femurkondylus am gunstigsten hinsichtlich ahnlicher Knorpeldicken und Krummungsradien zu sein. Die hauptsachliche Betrachtung der Knorpeldicke unter minderer Berucksichtigung der Krummung der Gelenkflachen sowie die Tatsache, den Knorpel nicht an den Hauptbelastungsstellen des Kniegelenks zu entfernen, um Lasionen des gesunden Gelenks zu vermeiden, erweist sich nach den Untersuchungsergebnissen als die sinnvollste Herangehensweise bei der autologen osteochondralen Transplantation.

As a response to research investigating the intraosseous vascularization and the special biomechanics of the calcaneus, a new theory of calcaneal cyst development was generated (retrospective patient study, n=4). A disturbance in local blood circulation occurs, due to, i. e., microembolus, thrombosis, or hematoma, at the neutral triangle where the major vessels penetrate the bone and separate. Following the disturbance in local blood flow, damaged tissues are resorbed. Due to the special biomechanics of the area, resorption is followed not by osseous remodelling, but instead by cyst formation. The two processes are histologically identical, including the presence of neovascularization, cholesterol plaques, hemosiderin and osteoid-lined cyst walls. Because of its sclerosed external wall, the benign calcaneal cyst is stable with normal biomechanics; however, eccentric weight-loading can lead to fractures.

Zusammenfassung Der Fus zeigt hinsichtlich seiner knochernen Strukturen und Bander eine sehr komplexe Anatomie. Eine ganze Reihe von Untersuchungen hat zu kontroversen topographischen Beschreibungen der Fuskompartimente, die unterschiedliche Muskeln und Sehnen zu funktionellen Gruppen zusammenfassen, gefuhrt. Die vorliegende Studie hat das Ziel, Klarheit in die zahlreichen konfusen Konzepte hinsichtlich der Topographie der Fuskompartimente und die damit zusammenhangenden Grundlagen der Fasziotomie zu bringen. Ein erster Schritt ist hierbei sowohl die Beschreibung der Topographie der Fuskompartimente einschlieslich des exakten Verlaufes der jeweiligen Muskeln und Sehnen als auch die Darstellung moglicher Verbindungen zwischen den Fuskompartimenten und ihre Beziehungen zur Unterschenkelmuskulatur. Daruber hinaus werden die Topographie der neurovaskularen Bundel innerhalb der Kompartimente und ihr Verlauf an der Fussohle diskutiert.

Operative problems in the application of femoral locking nails are frequently related to an unfavourable entry point at the greater trochanter. Especially in more distally located fractures the nail is forced to follow the cortex abutted medullary canal. A wrong defined entry point either in the medio-lateral or dorso-ventral direction inevitably leads to tension between nail and femur. Forceful insertion in this situation may cause disastrous iatrogenic comminution at the fracture side or additional fractures at the proximal femur. To avoid tension between nail and femur the best suited entry point must be defined according to the natural medullary cavity. In 16 human cadaver femora, the natural medullary cavity was opened and after cleaning filled with a radio-opaque substance (barium sulphate). Twelve radiographs where taken from each bone starting with the anterior-posterior view and then turning the bone axially in steps of 15 degrees. From these radiographs, the ideal entry point at the greater trochanter was calculated. In 88% of the specimen the ideal entry point for a straight nail was found constantly at the medial border of the greater trochanter overlaying the tendinous insertion of the piriformis muscle. The axis of the medullary cavity was in average 2.1cm anterior to the dorsal border of the greater trochanter. In a second step the ideal entry point for bend nails was calculated. According to this calculation a bend nail with a radius of 100 cm needs an entry point 0.7 mm anterior to the dorsal edge of the greater trochanter. Overlaying the hook like shape of the posterior part of the trochanter.

The clinical and functional importance of gliding spaces of the hand (e.g., their role in the spread of infection or as a consideration in reconstructive surgery) has been repeatedly emphasized. However, only a few studies have provided details regarding the connective tissue spaces in the metacarpal region of the dorsal side of the human hand. The aim of the present study was to analyze the morphology and elucidate the anatomic relation of functional gliding spaces in the metacarpal region on the dorsal side of the human hand in order to provide a better understanding of function, and of clinical disorders and their treatment. To delineate these spaces we used a plastic (Acrifix 90) injection method. Twenty fixed and unfixed cadaver hands were subcutaneously injected with Acrifix 90 (a methacrylate) into the metacarpophalangeal transitional region and into the tendon sheaths of the extensor muscles. Different colors were used to distinguish one injected plastic solution from another. The spreading pattern of the injected medium was analyzed by careful dissection. To delineate the exact bordering structures and the topography of the injected spaces, two hands were plastinated using the E12/E6 technique (von Hagens et al., Anat Embryol 1987;175:411-421), and one hand was injected and embedded in Technovit 7100 for histological investigations. Injecting the plastic into the metacarpophalangeal transitional region of fingers II-IV in a disto-proximal direction, the solution spreads along the surface of the separate extensor tendons. It then coalesces 1-2 cm proximal to the injection points to form a continuous plastic plate, which protrudes between and on top of the previous injected tendon sheaths. In no case was a communication between the paratendinous tissue and the tendon sheaths observed. Laterally, the injected solution is delimited at the radial side of the extensor tendon of the second finger and at the ulnar side of the extensor tendon of the fourth finger. Using the described technique at the fifth finger yields a plastic plate that extends from the injection point to the tendon sheath. However, in two specimens a connection between the plastic injected into the tendon sheath of the fifth finger, and the distal injected solution was observed.

The extent of soft tissue trauma in hindfoot injury (calcaneus fracture, talus fracture) is currently being underestimated. A standardization of magnetic resonance (MR) imaging of the hindfoot is necessary for better definition of pathological changes. Standardized MR imaging projections of the hindfoot were illustrated by anatomic analysis of specimen sections using the same sectional plane as in MR imaging. The plastinated sections were obtained from the same specimen that had been scanned previously. MR imaging of the hindfoot enables the assessment of the calcaneocuboid ligament, the interosseous talocalcaneal ligament, trauma of the foot sole, intraosseous and extraosseous vascularization, muscle compartments in the evaluation of compartment syndrome, chondral flake fractures, tendon dislocation, as well as tendon degeneration, and plantar fasciitis. These anatomical structures, which must be evaluated for preoperative planning, can be identified clearly by MR imaging.

External fixation is a well accepted treatment option in distal radial fractures. The fixator can be used in two different ways: joint bridging or extraarticular. The extraarticular technique presumes that the fracture does not involve the radio-carpal joint and that the distal fragment is broad enough to accommodate two fixator screws. Taking into account that the majority of distal radius fractures occur in elderly female patients the question arises whether osteoporotic bone is an obstacle to extraarticular external fixation. Bone slices of 2 mm thickness were cut out of six human cadaver radii with a mean age of 76 years (from 65 to 94 years) in the sagital plane. A radiograph of each slice was digitized and the distribution of gray values measured. It was found that the radiographic density was highest at the palmar side of the distal radius in a triangular area built by the palmar lip of the radius. In this region, even in severe osteoporotic bone, strong trabeculae are visible running parallel to longitudinal axis of the radius. Fixator screws inserted into the distal radial fragment especially in an osteoporotic situation should be securely anchored in the palmar lip of the distal radius.

For osteosynthesis in the epiphyseal region of long bones, specialized screw types are available to achieve a better purchase in cancellous bone. Typically, the cancellous bone screw has a large outer thread diameter with a relatively small core diameter and a great pitch. Due to its dimensions, this screw type is not suited for the cancellous bone areas in hand and foot surgery, respectively. Fine machine screws are better adapted to the bone dimensions in this part of the skeleton. To compare the holding power of fine machine screws with the holding power of other screw types available in the market, a biomechanical study was undertaken. Different screw types were compared: 4 mm cancellous screw, 3.5 and 2.7 mm cortical screws and three different diameters of a fine machine screw (2.2, 1.6 and 1.2 mm). Both cortical screws were tested in pretapped and self-tapping version. Polyurethane foam and bovine cancellous bone were tested. The screws were applied according to the manufacturer's instructions and an axial extraction force was applied. The 4 mm cancellous bone screws were superior to all the other screws in both test materials (P

The anatomic development of thyroglossal tract remnants is not understood at present. For analysis of morphology and growth patterns of thyroglossal tract remnants, we used histologic whole organ serial sections to determine developmental changes through the first years of life. Larynges of 58 infants and children ages 1 month to 13 years were obtained in whole organ serial step-sections in an axial plane. The slides were stained with hematoxylin and eosin, Alcian blue, and periodic acid–Schiff stains. Altogether, 3,247 histologic slices were examined. The resulting data were then correlated with the age and sex of the specimens. We found, in 24 cases (41.3%), remnants of the thyroglossal tract or ectopic thyroid tissue. In 4 specimens (16.6%), a complete thyroglossal tract could be observed that presented a ventral path in relation to the hyoid bone with no contact with the perichondrium of the cartilage. Hormonal activity of ectopic thyroid tissue was proven in 20 cases (34.5%). Thyroid follicles were located in 2 cases (3.5%) in the hyoid bone. The thyroglossal ducts revealed a modest tendency for a left-sided pathway, whereas thyroid follicles were located more on the right paramedian side. Morphometric data on the development and structure of the thyroglossal tract and the thyroid follicles during infancy and childhood are presented. The study provides quantitative data of clinical interest that elucidate the anatomy of thyroglossal tract remnants. In addition, our investigation supports Sistrunk's operative approach for avoiding recurrences in the treatment of thyroglossal duct cysts.