Biomedical subjects

J Koebke

Publications and source records attributed to J Koebke.

At least 55 records · Page 3Linked to original sources

PubMed1999

Miniarthroscopy of metacarpophalangeal joints in rheumatoid arthritis. Rating of diagnostic value in synovitis staging and efficiency of synovial biopsy.

OBJECTIVE: To evaluate miniarthroscopy (MA) (needle arthroscopy) of involved joints in rheumatoid arthritis (RA) in the early detection and staging of synovitis and its application in visual guided synovial biopsies. METHODS: 1.0 and 1.9 mm (0 degree/30 degrees) arthroscopes were used in a 2 portal technique. MA performance was developed and evaluated first on hand cadavers (n = 20) and then transferred to metacarpophalangeal (MCP) joints under local anesthesia conditions. Joints of 20 patients with RA with different disease activity and duration were scoped and rated according to scores adapted from arthroscopy of other joints. RESULTS: In 20/20 cases MA provided visualizing and magnification of intraarticular features of MCP joints in RA and allowed grading of synovial alterations, chondromalacia, and bony alterations. Synovial surface changes, thickness, and fibrosis were related to disease duration, as was damage to cartilage and bone. The degree of acute inflammatory reactions like vascularity and hyperemia varied independently of chronic changes; synovial proliferation was reflected to some extent by C-reactive protein. In 2 patients with early RA, synovitis criteria were found macroscopically and histologically. In 18/20 joints, biopsies were taken under visual control; in the other 2, progression of disease (Larsen score >3) limited arthroscopy to 1.0 scope imaging only. Sampling sizes were sufficient for histologic and molecular analysis. CONCLUSION: The developed standardized procedure of MCP arthroscopy is minimally invasive, practicable, and well tolerated by patients, and may allow synovitis monitoring, staging, and biopsy in patients with early as well as chronic arthritis.

Adult↗

PubMed1998

Mechanical strain at the pisotriquetral joint.

Pain and tenderness on the palmar and ulnar aspects of the wrist in the area of the pisiform bone is fairly common. Chronic pain in the pisiform area may be due to tendinitis of the insertion of the flexor carpi ulnaris, bony fractures or osteoarthrosis of pisotriquetral joint which is the second most common degenerative arthritis in wrist after the scaphotrapezial osteoarthrosis (Fischer, 1988, Radiologe 28:338-344). Subperiostal excision of pisiform bone is customarily performed after unsuccessful initial non-operative treatment (Carroll and Coyle, 1985, J. Hand Surg. 10:703-707; Johnston and Tonkin, 1986, Clin. Orthop. 210:137-142; Nüesch et al., 1993, Handchir. Mikrochir. Plast. Chir. 25:42-45). Although the postoperative results seem to be rather good, possible malfunction based on excision has not been considered previously by investigators. The aim of this study was to improve our understanding of the role of the pisiform and the pisotriquetral joint in the transfer of forces within the carpus. In a first part we examined 112 pisotriquetral joints by qualitative, quantitative and densitometrical analysis of joint surfaces. Secondly, mechanical tests were performed to investigate the distribution of forces within pisiform and the pisotriquetral joint. The results demonstrate that the pisiform mechanically contributes to the stability of the ulnar column of the wrist. The pisiform, and its unique anatomical holding mechanism, discharges two main functions. It holds the triquetrum in a correct position and prevents its subluxation even in extreme extension. Furthermore, it acts as a fulcrum (hypomochlion) while transducing powerful forearm forces to the hand. The excision of pisiform should be reconsidered.

Aged↗

PubMed1998

The lateral calcaneal artery.

An anatomic study of the lateral extraosseous and intraosseous arterial supply of the calcaneus and the lateral soft tissue was carried out on 10 fresh lower adult cadaver legs using different anatomic and radiologic procedures (plastination, modified Spalteholz clearing technique, digital subtraction and rotational angiography and computed tomographic angiography). Consistent patterns of extraosseous and intraosseous lateral calcaneal vascular anatomy were demonstrated. The lateral calcaneal artery is a branch of the anterior tibial artery which crosses over the calcaneal tuberosity and forms a large lateral arch with the lateral tarsal artery which is a branch of the dorsalis pedis artery. The intraosseous circulation is supplied laterally by the lateral calcanear artery, medially via the short branches of the lateral plantar artery. Comparing magnet resonance images after fresh calcaneal fractures the lateral calcanear artery may be interrupted by the impacted lateral bulge, by the conventional lateral surgical approach, or by applying a lateral osteosynthesis plate. This may cause avascular bone necrosis. Furthermore the lateral calcanear artery can clinically serve as a vascular pedicle for a local rotational skin flap to cover soft tissue defects of the heel.

Adult↗

PubMed1998

Comparative densitometric study of iliac crest and scapula bone in relation to osseous integrated dental implants in microvascular mandibular reconstruction.

The study was designed to compare dimension and density of four frequently used bone donor regions (the iliac crest, the lateral border of the scapula, the radius and the fibula) with regard to placement of endosseous dental implants in microvascular mandibular reconstruction. The first part of the study reports on the results of bone dimension and density findings for iliac crest and scapula bone. Nearly all of the iliac crests had adequate dimensions for the positioning of four 10 mm implants. In 63% of the scapulae, it was possible to place four 10 mm implants. In the case of the scapula, half of the female subjects lacked enough available bone for the insertion of four 10 mm implants because of their inadequate width. Bone density and cortical thickness was found to be similar in the iliac crest and scapula. Age and side do not have an important influence on cortical bone dimensions and density. In contrast to the iliac crest, the lateral margin of the scapula astonishingly showed increasing values for bone density and increasing thickness of the cortex. Analogical advanced biological age works in conformity with the scapula flap. The results could, together with other clinical criteria, contribute to the choice of the best individual alternative in mandibular reconstruction.

Adult↗

PubMed1998

[Movements of the pisiform and triquetrum bones and their significance for kinematics of the ulnar wrist].

The purpose of this study is to investigate carpal kinematics with respect to the pisotriquetral joint, before and after pisi-form excision. Five cadaver-hands were studied and a custom-designed plexi-glass-fixation device was used to standardize the wrists for exact passive movements in flexion and extension as well as in ulnar and radial abduction. Five sets of motion were registered before and after excision of the pisiform. Motion of the triquetrum and pisiform were studied by 3D-Motion Analysing Software System (peak 54). The results indicated that the excision of the pisiform does have an influence on the kinematics of the wrist. The movement of the triquetrum was increased after removal of the pisiform. Although the differences in measurement were only a few of millimetres and degrees, we know from the dorsal and palmar intercalated segment instabilities that even minor instabilities can act as a predisposing factor for arthrosis. Therefore, the excision of pisiform must be carefully considered. The common joint between the triquetrum and pisiform supports and indicates relation of their movements. However, the correlation for flexion/extension and radial deviation was high, an obvious correlation of the movements for ulnar deviation was not verifiable.

Biomechanical Phenomena↗

PubMed1998

[External stabilization of the metacarpal bones II to V. Anatomic-clinical study].

The four ulnar metacarpal bones are connected to each other at their proximal and distal ends by strong ligaments. The second and fifth metacarpal bones are the frame of the metacarpus. Surgically, this is of great importance. A fracture of these two bones often requires stabilization, whereas a fracture of the third and fourth metacarpal bones with intact ligaments seldom requires surgery except in cases of severe fragment dislocation. Using external fixation for these purposes it seems to be of utmost interest to define secure pintracks through the soft tissue. In an anatomical study using formalin fixed specimen it clearly could be demonstrated that the second and fifth metacarpal bones are best suited for external fixation. The second metacarpal bone should always be fixed from the radial side because the fixator pins can be inserted within a wide range of angles without the risk of violating the extensor tendons. Variations of tendons and ligaments are seldom located on the radial side of the second metacarpal bone and therefore, finger movement is unhindered after pin application. A similar consideration is true for the fifth metacarpal bone which should be fixed from the ulnar side. With respect to the extensor tendon which covers the entire dorsal surface of the fifth metacarpal bone, the angle of the pins should be 40 to 90 degrees from the dorsal side. For the third metacarpal bone, fixation from the radial side is preferable taking topographical and biomechanical considerations into account. The radial corridor to the fourth metacarpal bone is smaller than the ulnar corridor, but there is much less morphological variability of the extensor tendons than on the ulnar side where strong fibres often cross the fourth intermetacarpal space. Because in the proximal fourth of the metacarpal bones the tendons are located very close to each other, a small skin incision and preparation to the bone surface is advisable to exclude violation of the tendons when inserting fixator screws into the third and fourth metacarpal bones. Using formalin-alcohol fixed cadaver specimens for the research gives an idea of the anatomical situation in the dorsal metacarpus but cannot answer the question whether the tendons in the lax subcutaneous tissue of the living will automatically slip aside when the fixator pin approaches. This should be item to subsequent studies in fresh frozen specimens and follow-up studies in a larger amount of patients treated with external fixation.

External Fixators↗

PubMed1998

[What is the value of biomechanical knowledge for surgery of the hand?].

Cartilage and bone as supportive tissues are submitted to mechanical stresses and react to these in a very specific manner. Functional adaptation to the quality and magnitude of the acting forces is the result. In this article, the basic principles of functional adaptation of cartilage and bone will be presented. On the basis of these principles, promising functional concepts and clinical treatments may be established; this will be shown by some examples concerning the hand.

Adaptation, Physiological↗

PubMed1998

[Changes in the form of the interosseous hood during extension and flexion of the metacarpophalangeal joint].

Finger flexion initiated at the distal and proximal interphalangeal joint level forces the extensor tendon to move distally. Therefore, the interosseous hood fixed to the extensor apparatus moves distally, too. The proximal part of the hood which is located at the level of the metacarpal head during extension of the finger slides distally along the basis of the proximal phalanx. Due to the much smaller cross-section of the phalanx compared to the metacarpal head, the palmar border of the interosseous hood is shifted palmarly. This produces a two-fold effect concerning the metacarpophalangeal joint. First, it leads to an increasing flexion moment of the intrinsic muscles during flexion of the metacarpophalangeal joint. Second, the same mechanism improves the ability of abduction and adduction in the metacarpophalangeal joint during extension of the finger. In this position, the proximal part of the interosseous hood covers the metacarpal head and the strong palmar bundles of the hood are pushed to the ulnar and radial sides resulting in a greater distance to the abduction/adduction axis of the MP-joint. The other effect concerns the proximal interphalangeal joint. The described transformation of the interosseous hood during flexion especially of its proximal part causes a curved deformation of the strong palmar border of the interosseous hood. The power of the intrinsic muscles inserting at the interosseous hood is passed along this smooth curve on its way to the dorsal side of the proximal interphalangeal joint thus allowing a continuous extension of the proximal interphalangeal joint in all flexion phases of the MP-joint. The typical transformation of the interosseous hood is regulated by the form of the underlying bone and ligament apparatus and can be understood as a passive mechanism effecting in a senseful change of muscle function as the active element during finger flexion and extension. These not yet described morphological data concerning the transformation of the interosseous hood during finger flexion and the functional interpretation complete the former described mechanism of flexion by Landsmeer (1955) and Landsmeer and Long (1965).

Biomechanical Phenomena↗

PubMed1998

[Effect of implants in the metacarpal head and proximal phalanx on mobility of the metacarpophalangeal joint. An anatomic study].

Percutaneous application of Kirschner wires, fixator pins, or other implants near the metacarpophalangeal joint may lead to postoperative disability of movement with subsequent joint stiffness. To determine the best location for the application of implants into the metacarpal head and the basis of the proximal phalanx, 57 Kirschner wires were introduced into the metacarpal head and into the bases of the proximal phalanx and the resulting stiffness has been measured. Kirschner wires inserted at the level of the dorsal tubercle or proximal to the tubercle, do not lead to a noteworthy stiffness. Whenever possible, this tubercle should be taken as the distal border for inserting implants. If the position of the fracture line makes it necessary to implant wires into the metacarpal head itself, a more dorsal application is preferable. If a palmar placement cannot be avoided, the implantation should be done in neutral position of the metacarpophalangeal joint, because a transfixation of the tense collateral ligament in flexion leads to a maximum of postoperative stiffness. The application of wires into the basis of the proximal phalanx does not influence the range of movement of the metacarpophalangeal joint.

Biomechanical Phenomena↗

PubMed1997

The arterial supply of the ankle joint and its importance for the operative fracture treatment.

The operative exposure of a fracture causes disturbances in the blood supply, which may lead to a prolonged healing process or even to bone necrosis, especially when using the complex and complicated methods of osteosynthesis at the ankle. In order to damage the supplying vessels as little as possible, position, direction and penetration of the bone arteries of the talocrural joint were examined by corrosion preparation. The tibial nutrient artery arises from the posterior tibial artery or from the popliteal artery and penetrates constantly from posterior at the level of the proximal third. The fibular nutrient artery, coming from the peroneal artery, penetrates more distally from medial into the middle third of the diaphysis. In one specimen it did not exist at all. Distal tibia and fibula are supplied by the perimalleolar arterial ring, which is connected with the three arteries of the leg. The talus is supplied by numerous very small vessels, which are provided with extraosseous anastomoses and penetrate the whole non-articular surface. Implications for the operation will be explained.

Adult↗

PubMed1997

Arterial supply of forearm bones and its importance for the operative treatment of fractures.

The operative exposure of a fracture in an osteosynthesis causes disturbances in the blood supply, which often leads to a prolonged process of healing or even to healing problems, a fracture non-union, which is frequently located at the forearm. In order to damage the supplying vessels as little as possible, the position, direction and penetration of the arteries of radius and ulna are demonstrated and systematised in this study. Near the elbow arteries, coming from large adjoining vessels, penetrate the area of the capsular insertion. The nutrient arteries enter both bones in the second proximal quarter of diaphysis, at the radius from anterior to medial, at the ulna from anterior to anteroradial. Small vessels, which penetrate closely proximal to the articular surface in order to supply the distal forearm bones, come from an anastomosis between the radial, the interosseous and the ulnar arteries. In this study access vessels, choice and position of implants will be discussed.

Aged↗

PubMed1997

Radiologic anatomy of the metacarpophalangeal joints II to V.

The metacarpophalangeal (MCP) joints II to V of 21 hands were examined radiologically and arthrographically. Different recesses of the joint cavity were demonstrated both radiologically and macroscopically, with a dominating dorsal recess. The existing forms of the dorsal recess were one-tailed, two-tailed, three-tailed, symmetric and cap-like. Additionally, a palmar recess was found in the specimens examined, which presented as a small protrusion of the capsule and lay between the metacarpal head and the palmar plate. Furthermore, a distal recess was filled and unfolded in almost all the cases. Lateral recesses were found in the radial and ulnar directions beneath the collateral ligaments. The dorsal recess, due to its ability to collect fluid, is of clinical importance in pathologic processes causing effusions, while the clinical importance of the lateral recesses lie in their proximity to the stabilizing collateral ligaments of the metacarpophalangeal joints. The above mentioned recesses were seen as normal formations of the MCP joints and should therefore be taken into account in pathologic processes in this area.

Aged↗

PubMed1997

[Anatomy of the brachial plexus].

The early development of the brachial plexus shows that it is formed of a dorsal branch supplying the extensor muscles and a ventral branch for the flexor muscles. Although the network becomes more and more complex, a basic pattern is generally preserved. This basic pattern, as well as variants and the topography of the lateral neck triangle, is described.

Arm↗

PubMed1997

Finite-element modeling of the human neurocranium under functional anatomical aspects.

Due to its functional significance the human skull plays an important role in biomechanical research. The present work describes a new Finite-Element model of the human neurocranium. The dry skull of a middle-aged woman served as a pattern. The model was developed using only the preprocessor (Mentat) of a commercial FE-system (Marc). Unlike that of other FE models of the human skull mentioned in the literature, the geometry in this model was designed according to functional anatomical findings. Functionally important morphological structures representing loci minoris resistentiae, especially the foramina and fissures of the skull base, were included in the model. The results of two linear static loadcase analyses in the region of the skull base underline the importance of modeling from the functional anatomical point of view.

Female↗

PubMed1997

[Anatomy of the abdominal wall--an area at risk for hernias].

The muscles as well as the fibrous elements of the abdominal wall will alter their function in man due to his upright position, although the abdominal wall's architecture remains ancestrally. The abdominal muscles quit the only function of visceral weight bearing; they are now additionally important for trunk movements and the stabilisation of the vertebral column. Bipedalism leads to a special intraabdominal pressure distribution, predetermining the more caudal regions of the abdominal wall to herniation.

Abdominal Muscles↗

PubMed1996

Morphology of the articular surfaces of the distal radio-ulnar joint.

BACKGROUND: The two articular surfaces of the distal ulna get an important role in load transmission and stabilization of the distal radio-ulnar joint. The present study describes the morphology of the distal radio-ulnar joint surfaces in terms of the functional relationships between the shape of the ulnar articular facets and the predominant contact situation in this joint. METHODS: Besides macroscopic dissection and radiological investigation the model of the "inclined plane" has been used to simulate force transmission across the radio-ulnar joint concerning the angle between the distal and the radial articular surfaces of the ulnar head. RESULTS: The presented morphological parameters of the radio-ulnar joint surfaces verify that the transmitted forces are effective in both a radio-ulnar and an axial direction. The protection and the captaincy of this joint are limited by its great mobility. The investigations show that signs of an increased load pressure are frequently found in the joints that also show degenerative changes. As a morphological sign of the force transmission, distinct spongious trabecles are formed perpendicularly to the articular circumference in those ulnar heads that show a stolid angle between their articular facets. CONCLUSIONS: Because of the individuality of the morphological data only qualitative statements can be made both the predominant shapes of the ulnar head, in particular about the loading of its articular surfaces. The angle between its two articular facets influences the force transmission through the radio-ulnar joint as well as the spongious architecture of the subchondral bone of the ulnar head.

Aged↗

PubMed1996

Arthrosis in the peritrapezial joints of the hand.

In the present study saddle joints of the thumb and neighboring joints of 100 anatomic specimens are examined with regard to radiological and macroscopic arthrotic alterations. Comparisons of radiological and macroscopic findings demonstrate that early arthrotic articular alterations cannot be diagnosed radiologically. Almost half of the hands examined displayed arthrotic lesions in the saddle joint of the thumb, whereas the trapezoido-scaphoidal and trapezio-scaphoidal joints are each affected in one third. Hands with manifest thumb saddle joint arthrosis are accompanied by arthrotic alterations of the joints between the scaphoid, trapezium and trapezoid in two-thirds of the cases. In the remaining radial intercarpal joints, no macroscopic evidence can be ascertained of arthrotic alterations. Among the processes discussed as causal factors of simultaneous incidence of scaphoidal and carpo-metacarpal arthroses, the architecture of the osseous carpus, the individual expression of the scaphoid bone and poly- or secondary arthrotic processes are important.

Adult↗

PubMed1996

Functional gliding spaces of the dorsal side of the human finger.

Although the clinical and functional importance of gliding and connective tissue spaces has been repeatedly emphasized (e.g. their role in the spreading of suppurative phlegmonic inflammation) only few literary findings can be presented dealing with the connective tissue spaces in the finger in the metacarpo-phalangeal transition region. Three separate gliding spaces of the finger above the dorsal aponeurosis and their various regional connections can be displayed by means of a plastic injection technique followed by plastination and production of sectional series. These gliding spaces were also examined on fixed and unfixed hands using plastic injection and subsequent dissection. A space was depicted between the proximal interphalangeal joint and the insertion of the dorsal aponeurosis on the distal phalanx of the finger, as well as a further bursa-like space over the proximal interphalangeal joint. A third space was also depicted between the metacarpophalangeal joint and the proximal interphalangeal joint, which displays a variable connection to the gliding canal of the respective extensor tendons. Methodical, functional and clinical aspects will be discussed.

Cadaver↗