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Biomedical subjects

U Lanz

Publications and source records attributed to U Lanz.

At least 55 records · Page 3Linked to original sources
PubMed1999

[Biomechanical aspects of malunited distal radius fracture. A review of the literature].

BACKGROUND: One of the most common injuries in orthopaedics is the distal radius fracture. Malunion may lead to pain, limited motion, and loss of grip strength. Presently there is no consensus concerning the indications for corrective surgery after malunion. Studies concerning the biomechanics of the wrist in cases of malunited radius fracture can be helpful. METHOD: Analysis of the literature of the last ten years. RESULTS: In laboratory studies, malalignment of the radius caused alterations of the distal radioulnar joint (anatomically: reduction of the radioulnar contact area, disruption of the deep portion of the dorsal radioulnar ligament, tightness of the triangular fibrocartilage complex; functionally: limited forearm pronation and supination). Further alterations have been found concerning the carpal kinematics, the force transmission through the wrist, the pressure distribution on the articular surface of the radius and the median nerve. CONCLUSION: Attempts should be made to obtain an anatomic reduction of all acute distal radius fractures. Posttraumatic disability of the wrist following malunion in radius fractures should accordingly be treated by a corrective osteotomy of the radius at the original fracture site.

Biomechanical Phenomena↗
PubMed1999

Severe Contractures of the Proximal Interphalangeal Joint in Dupuytren's Disease:Value of Capsuloligamentous Release.

A retrospective review of severe flexion contractures (60 degrees or more), involving 51 proximal interphalangeal joints in 40 patients with Dupuytren's disease, was performed. Thirty-two joints underwent aponeurectomy alone, 19 joints additional capsuloligamentous release. Mean follow-up was 12 months. No statistically significant difference was seen in the percentage of contracture correction in the capsulotomy group compared with the noncapsulotomy group.

Journal Article↗
PubMed1999

[The importance of the distal radioulnar joint for reconstructive procedures in malunited distal radius fracture].

Clinically most patients complain about ulnar sided wrist pain and limited forearm rotation following malunited distal radius fractures. Possible bony reasons consist of intraarticular incongruency, malalignment of the sigmoid notch of the distal radius or the ulna-plus-situation at the wrist level. A persisting luxation of the distal radioulnar joint (DRUJ) will present itself with complete loss of forearm rotation. The ligamentous or bony detachment of the triangular fibrocartilage complex (TFCC) will lead to instability of the DRUJ. Uncorrected, each of these components will lead to arthrosis of the DRUJ. The presence of arthrosis only allows salvage procedures for the DRUJ and will lead to functional loss. Reconstructive options consist of radius correction osteotomy, ulnar shortening osteotomy, reposition of a luxation and refixation of the TFCC. To chose the necessary reconstructive procedure, the individual pathological situation has to be analysed.

Fractures, Malunited↗
PubMed1999

[TFCC (Triangular Fibrocartilage Complex) lesions. Diagnosis and therapy].

Lesions of the TFCC may have degenerative or post-traumatic causes. Distal radioulnar joint as well as the ulnocarpal joint can be affected. Patients present with ulnar-sided wrist pain especially in forearm rotation. Therapy depends on the degree of lesions and additional pathology. Wrist arthroscopy offers a certain diagnostic tool. In addition, adequate therapy can be realized. After failed arthroscopic therapy, ulnar shortening osteotomy reduces ulnar load significantly.

Arthroscopy↗
PubMed1998

[Free toe transplantation in reconstructive hand surgery].

Since the invention of microsurgical techniques the free toe-to-hand transplantation is an established method for reconstruction of hand function. The indication for this method following thumb and finger amputations as well as congenital defects with aplasia of the fingers and the thumb is discussed in comparison to alternative operations. The operative technique as well as the functional and aesthetic results that can be expected are described by presentation of clinical cases. Since 1992 we performed 18 free toe-to-hand transplantations for the above mentioned indications. Depending on the primary situation the elementary hand function with grip and pinch could be restored in all our patients using this method. Restoring sensibility next to length, mobility and strength in one operation has to be considered as an advantage compared to alternative methods.

Female↗
PubMed1998

[Not Available].

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Journal Article↗
PubMed1998

[Replantation. Indications and organization].

Although experience in replantation surgery increased during the past 30 years, there are still problems remaining. Refinement of microsurgical operations and improvement in rehabilitation technique have lead to superior functional results. Beside clear indications as thumb loss or replantation in children there are only few absolute contraindications. A retrospective analysis of more than 300 replantation showed that there are still problems concerning exhaustive supply of replantation centres. Because time is one of the many critical components of successful preplantation improvements are necessary in extra- and intrahospital organization of replantation surgery.

Adolescent↗
PubMed1998

[Transplantation of the M. gracilis in the reconstruction of hand function].

Free muscle transplantation with motor innervation offers the possibility to add contractile elements to upper extremities with extensive loss of musculature due to direct trauma or untreated compartment syndrome (Volkmann's contracture). The functional cross section area and the mean resting fiber length determine the maximum power and the contracting amplitude of the donor muscle. Although considerably weaker than the finger flexors to be replaced, the gracilis muscle was the preferred donor muscle because of its neurovascular pedicle and the minimal donor site morbidity. In a series of 15 gracilis transplantations, all 13 muscles that survived regained function. Finger motion was dependent on the preoperative condition of tendons and joints. Even after complete loss of the flexor and extensor compartment a useful upper extremity could be restored, which was preferable to the only alternative-amputation.

Adolescent↗
PubMed1998

The hypothenar fat-pad flap for reconstructive repair after scarring of the median nerve at the wrist joint.

Because of the loss of mobility, scarring of the median nerve in the carpal tunnel can lead to chronic pain syndrome of the wrist joint, with reduced sensation, muscular dystrophy and severe limitation of the use of the hand. This syndrome most often appears following open carpal tunnel release. Nine patients with scarring of the median nerve in the carpal tunnel were treated with a hypothenar fat-pad flap. Eight of them showed a significant reduction in pain, with improved sensation, trophism and strength. The procedure is suitable as a salvage procedure for restoring a sliding pathway and for cushioning the median nerve in the presence of recurrent lesions in the carpal tunnel.

Adult↗
PubMed1998

[Stress on the wrist joint in semilunar bone necrosis--a morphologic study in vivo].

The distribution of subchondral mineralization of the distal articular surface of the radius was examined by CT osteoabsorptiometry in both wrists of twelve patients showing different stages of Kienböck's disease. The pattern of density distribution had already been demonstrated in previous studies to be an adequate parameter for assessing axial loading across the wrist joint in the patients. Contrary to the anticipated presence of predominant stress in the lunate compartment, some patients showed identical stress in the compartment of the scaphoid, and the balanced loading of both compartments, as before. Even when in early stages of the disease the lunate type of mineralization appeared more often, it was still not possible to demonstrate general excessive stress on the lunate. We have therefore concluded that the main stress in the scaphoid compartment might be a secondary effect, which is to be regarded as the expression of the advancing destruction of the lunate and consequent loss of load transmission through this compartment. This hypothesis is also supported by the fact that, in progressive stages of Kienböck's disease, the density maximum in the fovea lunata, generally present in healthy people, is absent. Furthermore, in patients with necrosis of the lunate, the total mineralization in terms of the maximal density values in the distal joint surface of the radius is in the majority of cases less than in the normal subject. In two cases, even the density maximum was absent from the fovea lunata of the contralateral wrist joint, without there being any clinical signs suggesting a possible lunate necrosis on this side. We interpret these pathological changes in the unaffected wrist joint as a further indication that we are dealing with a congenital predisposition which affects both wrist joints.

Absorptiometry, Photon↗
PubMed1998

[STT arthrodesis as therapy of lunate necrosis in an advanced stage].

The results of STT-fusion for treatment of advanced Kienböck's disease were investigated in a retrospective study. The follow-up included 25 of 28 patients, the average follow-up time was 39 months. Pain relief, range of motion, grip strength and X-ray findings were the most important criteria for rating the results. On the one hand, there was a decrease of range of motion, but on the other hand, grip strength improved markedly. Of course, one part of the decrease of pain is caused by the performed partial denervation of the wrist. However, the decrease of pain was impressive.

Adult↗
PubMed1998

[Compression of the ulnar nerve in Guyon's canal by a traumatic aneurysm. A case report].

A patient developed after an occupational trauma with fall on the ulnar edge of his right hand pain and swelling in the ulnar area with reduced sensation in the fourth and fifth finger. After examination performed by a neurologist, ulnar nerve-entrapment was diagnosed and operative treatment was indicated. The release of the ulnar tunnel showed a traumatic aneurysma of the ulnar artery compressing the superficial branch of the ulnar nerve. The tumor was removed and end-to-end anastomosis ensued. Four weeks after surgery, examination showed complete recovery. Various reasons of ulnar tunnel syndrome are discussed.

Adult↗
PubMed1998

["Around the head of the ulna": injury pattern and classification].

The ulnar head represents a keystone for normal forearm function. A complex system of soft tissues stabilizes the radius and the ulnocarpal joint against the ulnar head which is an essential part of the distal radioulnar joint as well as the ulnocarpal joint. Injuries around the ulnar head can destabilize these joints leading to loss of congruity and secondary arthrosis. The different injury patterns can result in axial or transverse instability. Axial instability primarily affects ulnocarpal function, transverse instability the function of the distal radioulnar joint. The injury pattern determines the degree of bony and soft tissue lesions that will clinically present in a variety ranging from acute dislocation to chronic instability of the ulnar head. An early and exact diagnosis of the injured structures with their anatomical reconstruction is necessary to avoid secondary arthrosis that will result in functional impairment of the distal radioulnar and ulnocarpal joints.

Fracture Fixation, Internal↗
PubMed1997

[Not Available].

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Journal Article↗
PubMed1997

[Replacement operations in radial paralysis].

Radial nerve palsy results in a lack of extrinsic extensors of the wrist, fingers and thumb. The degree of dysfunction depends on the level of trauma to the radial nerve. If the wrist is not stable there is a loss of prehensile grip. Patients have great difficulty picking up large or heavy objects. In high radial nerve palsy the loss of triceps function can cause additional problems. Based on our knowledge of anatomy and biomechanics, radial nerve function can be restored sufficiently. The indications, preoperative planning, technique of transposition and postoperative management are explained.

Arm Injuries↗
PubMed1997

[Surgical therapy of camptodactyly].

Camptodactyly is caused by an imbalance between the flexor and extensor forces at the proximal interphalangeal joint of the fingers. Although the etiology is not completely clear, the lumbrical muscle anomalies seem to play an important part in the pathogenesis of camptodactyly. The insertion of this intrinsic muscle often differs greatly from that described in anatomical textbooks. In our series, we transposed the lumbrical muscle and the superficial flexor tendon to the extensor tendon creating a better balance between extensor and flexor forces. Additionally, we performed skin-lengthening procedures and, if necessary, an arthrolysis of the proximal interphalangeal joint. In this study, we present a new classification of preoperative guidelines to ameliorate the operative treatment of camptodactyly.

Adolescent↗