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Biomedical subjects

C J Wirth

Publications and source records attributed to C J Wirth.

At least 19 recordsLinked to original sources
PubMed1999

[Growth behavior of chondrocytes on various biomaterials].

Chondrocytes can be cultured on different three-dimensional culture systems suitable for transplantation to enhance the repair of localized cartilage defects. Articular cartilage chondrocytes from adult rabbit knees and from bovine calf metacarpophalangeal joints were isolated by enzymatic digestion and cultured in a monolayer system to amplify cell count. After amplification the cells were seeded on different biocompatible materials. We investigated two types of bioresorbable polymer fleece matrices (a composite fleece of polydioxanon and polyglactin and a resorbable poly-L-lactic acid fleece) and lyophilized dura as a biological carrier. On all three types of transport media the phenotypic and morphological appearance of cultured chondrocytes could be observed. The production of glycosaminoglycans was revealed by Alcian blue staining and immunohistochemical detection of Chondroitin-4 and 6-sulfate in the created constructs. The material properties of the carriers allow for transplantation of the artificial cartilage-like products into full thickness articular cartilage defects and could therefore improve the minor intrinsic healing capacity of cartilage tissue. Bioartificial cartilage may become a future perspective in the treatment options of orthopaedic and plastic surgery.

Animals↗
PubMed1998

The dilemma with multiply reoperated knee instabilities.

The treatment of instability of the multiply reoperated knee is a complex problem. The causes for failure are numerous and include repeated trauma, insufficient fixation and non-anatomic placement of the graft, inadequate replacement material, isolated anterior cruciate ligament (ACL) reconstruction in complex knee instability or the use of a ligament prosthesis. With every surgical procedure, however, the anatomical and technical conditions become worse. Problems like degenerative changes, joint stiffness and gait abnormalities occur and often become a more focal point than the instability itself. The purpose of this paper is to present the problems and the dilemma of instability of the multiply reoperated knee and the possible solutions. Between 1976 and 1996, a total of 1752 ACL reconstructions were carried out in Munich and Hannover. Of these, 228 (13%) were revision, mostly of failed ACL reconstructions performed elsewhere. Since 1989, we have chosen the severest cases from this group (more than three operations on the same knee) for this study. Seventeen patients were investigated who had undergone up to 25 operations. The mean number of operations was 7. All primary operations were performed in other hospitals. In 10 cases only the ACL reconstruction was performed as a final procedure, mostly in combination with other procedures like medial meniscus replacement, extra-articular stabilization or arthrolysis. In the other cases operations such as osteotomies, arthrodesis or amputation were necessary. The results present the main dilemma in instability of the multiply reoperated knee since they were not successful in all patients. Finally, 15 patients report still having instability, pain or swelling in isolation or in combination. Nine patients were satisfied with their subjective results. Even after the socalled definitive procedures, certain complications arose. The main goal in the treatment of instability of the multiply reoperated knee is to avoid a series of operations, hospitalization and history of illness. General revision surgery for the entire complaint is not the aim of the treatment. The specific problem of the patient should be extracted from the complex situation, and this should be solved with the most limited procedure possible only.

Adult↗
PubMed1998

Synthesis of articular cartilage-like tissue in vitro.

Defects in mature articular cartilage do not heal without residues, and therefore they remain a challenging problem in orthopaedic surgery. Modern tissue culture techniques facilitate the synthesis of cartilage-like tissue. A requirement of retaining the phenotypic characteristics of chondrocytes in vitro is the use of three-dimensional culture techniques. Articular chondrocytes of adult rabbits were isolated and cultured on different transplantable media for several weeks. A resorbable fleece, a non-absorbable net and lyophilized dura were used. Viability was tested by immunohistochemical techniques. Deposition of extracellular matrix could be observed by electron microscopy. The phenotypical and morphological appearance of cultured chondrocytes was preserved on the resorbable polymer fleece and the lyophilized dura. Cells cultured on the non-absorbable net had a more fibroblastic appearance. The resorbable fleece is apparently most suitable in terms of viability of the cultured chondrocytes and biocompatibility. The cultured three-dimensional artificial cartilage constructs reveal a future possibility for autologous cartilage transplantation into mature cartilage defects.

Animals↗
PubMed1998

Follow-up results 17 years after resection arthroplasty of the great toe.

Resection arthroplasty of the first metatarsophalangeal joint is a well-known operation. The follow-up results more than 17 years after arthroplasty for hallux valgus are reported and discussed. Between 1971 and 1980, 335 resection arthroplasties were performed on 205 patients. The sole indication for resection arthroplasty of the great toe in this study was hallux valgus. The technique involved removal of the proximal one-third of the phalanx with interposition of a capsular flap, occasionally including temporary Kirschner wire fixation. After 17.6 years on average, 102 patients were re-examined clinically and radiographically. Questionnaire assessment revealed a significantly prolonged walking distance, and 70% of the patients were pain-free at follow-up investigation, whereas 67% suffered from severe pain before the operation. Clinical evaluation showed diminished weight-bearing of the great toe during walking and a reduced range of motion of the resected first metatarsophalangeal joint. Radiographic shortening of the proximal phalanx was 37%. The average hallux valgus angle was 23 degrees at follow-up and 34 degrees prior to surgery. The unacceptably high rate of hallux valgus relapse, especially due to a high intermetatarsal angle, emphasizes the unsatisfactory long-term results of the resection arthroplasty. We now recommend this operation for older patients only, and a differentiated approach using reconstructive procedures according to the clinical and radiographical situation for younger patients.

Adolescent↗
PubMed1998

Trapezius transfer after brachial plexus palsy. Indications, difficulties and complications.

Most brachial plexus palsies are due to trauma, often resulting from motorcycle accidents. When nerve repair and physiotherapy are unsuccessful, muscle transfer may be considered. Paralysis of the deltoid and supraspinatus muscles can be addressed by transfer of the trapezius. Between March 1994 and June 1997 we treated 38 patients with brachial plexus palsy by trapezius transfer and reviewed 31 of these (7 women, 24 men) after a mean follow-up of 23.8 months (12 to 39), reporting the clinical and radiological results and subjective assessment. The mean age of the patients was 29 years (18 to 46). The operations had been performed according to the method of Saha described in 1967, involving transfer of the acromion with the insertion of the trapezius to the proximal humerus, and immobilisation in an abduction support for six weeks. Rehabilitation started on the first postoperative day with active exercises for the elbow, hand and fingers, and electrical stimulation of the transferred trapezius. All 31 patients had improved function with a decrease in multidirectional instability of the shoulder. The average increase in active abduction was from 7.3 degrees (0 to 45) to 39 degrees (25 to 80) at the latest review. The mean forward flexion increased from 20 degrees (0 to 85) to 44 degrees (20 to 90). Twenty-nine of the 31 were satisfied with the improvement in stability and function. Trapezius transfer for brachial plexus palsy involving the shoulder improves function and stability with clear subjective benefits.

Adolescent↗
PubMed1997

[Trapezius transfer in deltoid paralysis].

In most cases the genesis of brachial plexus palsy is traumatic, often because of bike accidents. If physiotherapy and neurosurgical procedures such as nerve repair do not have the desired outcome, muscle transfer operations are possible. The results of our favored transfer of the trapezius muscle to compensate paralysis of the deltoid muscle will be presented. Preoperatively radiological, clinical and electromyographic examinations are necessary. Our results are based upon the clinical and radiological check ups and the subjective assessment of the patients. Thirty-one patients (7 female, 24 male) underwent a trapezius transfer between March 1994 and December 1996. The average age was 29 years (range 18-46 years). We performed the operations using a modification of Saha's technique. With the patient in lateral decubitus position and protection of the opposite plexus, a sagital skin incision is the first step, followed by the preparation of trapezius and deltoid muscle as well as the bony parts of the shoulder (acromion, clavicle, scapular spine). The deltoid origin is cut from the lateral third of the clavicle, the acromion and the lateral half of the scapular spine. The next step is transection of the roof of the acromion and the lateral clavicle. After elevation of the remaining trapezius insertions from the clavicle and scapular spine, the proximal humerus is exposured by splitting the partly detached deltoid muscle longitudinally. Then the acromion fragment and humerus are prepared for the bone-to-bone contact. In 90 degrees of abduction the acromion fragment with its trapezius insertion is transferred and fixed to the humerus with two 4.5-mm screws. Finally the deltoid is sutured on the top of the trapezius and the skin is closed over two suction drains. Postoperatively we immobilize the operated arm in an abduction support for 6 weeks. The physiotherapy program starts on the first postoperative day with active training of elbow, hand and fingers and electrostimulation of the transferred trapezius muscle. Six weeks after the procedure we take an X-ray and start with progressive adduction of the arm. The preoperative subluxation of the humeral head was abolished in all cases. We achieved an average increase of active abduction from 7.3 degrees (range 0-45 degrees) preoperatively to 39.2 degrees (range 25 degrees-80 degrees) 1 year after the operation; the increase of forward flexion was from 20 degrees (range 0 degrees-85 degrees) to 43 degrees (range 20 degrees-90 degrees). All patients were satisfied with the improvement of stability and function of the operated shoulder. Finally we can conclude that the trapezius transfer for flail shoulder gives a satisfactory outcome regarding shoulder function and stability as well as the subjective situation of the patients.

Adolescent↗
PubMed1997

[Effect of surgical technique on meniscus transplants. A histological, animal experiment study].

After transplantation, a meniscus undergoes alterations in mechanical loading, which causes changes in its histological structure. We studied the degenerative effects on meniscus and tibial cartilage resulting from variations in the congruity or the isometric fixation of medial meniscus transplants. In three groups of five sheep each, the menisci were transplanted in three different ways, using the same operative approach. The menisci were evaluated 24 weeks after operation. In group 1, the meniscus was totally detached from its base at the capsule and refixed without changes in the congruity or isometry. This group provided the basic data. In group 2, the contralateral medial meniscus was turned upside down and transplanted. The reattachment was performed according to isometric conditions. With this technique the congruity of the tibial and femoral surface was modified. In group 3, the medial meniscus was reimplanted by choosing defined non-isometric fixation points for the anterior and posterior meniscal ligaments without changing the position of the corpus. For evaluation, the morphological alterations of meniscus and tibial cartilage were assessed by the Jackson score. The more distinct changes of the meniscus were assessed histologically by three criteria: surface cells, surface fibers and changes in the meniscus center. The highest degree of degenerative changes occurred in group 3 (score 4.5); however, considerable changes were also found in group 2 (score 3.5). Incongruous or non-isometric placement of a meniscal graft will lead to degeneration and failure of the graft.

Animals↗
PubMed1997

Medial meniscus replacement by a fat pad autograft. An experimental study in sheep.

The medial meniscus in 15 sheep was replaced by a pediculated infrapatellar fat pad graft and resulted in the development of a macroscopically meniscus-like structure within 6 months. Five additional sheep with a meniscectomy were controls. Degenerative changes in the fat pad autograft were visible after one year. Osteoarthritis of the weightbearing medial compartment was detected after 6 months. A temporary protective effect on the cartilage could be attributed to the autograft, but the long term results indicated that this was not permanent. Fat is not suitable as a meniscal substitute.

Adipose Tissue↗
PubMed1997

Reconstruction of the lateral ligaments of the ankle using a regional periosteal flap.

We have treated 94 patients with chronic instability of the lateral side of the ankle by reconstruction of the ligaments with local periosteal tissue. We reviewed 90 cases after a mean follow-up of 2.8 years (2 to 9) using a questionnaire, clinical examination and radiography. The results on a 100-point ankle score indicated that 81% had a good or excellent result. The periosteal flap-replacement technique allows anatomical reconstruction and does not sacrifice other ligaments or tendons in the foot.

Adolescent↗
PubMed1997

[Cartilage cell transplantation. Experimental principles and clinical applications].

Transplantation of autologous chondrocytes proliferated in vitro to treat cartilage defects is discussed controversially. Cartilage has only a very limited capacity to regenerate. The repair tissue is of minor biomechanical stability and therefore induces degenerative arthritis of joints in the long term. Facial cartilage defects may lead to aesthetic or functional problems. Different biological and synthetic substitutes were used to treat cartilage defects in orthopaedic and facial plastic surgery. Biological tissue for transplantation is not abundant and synthetic materials may induce foreign body reactions. Amplification of autologous cells in vitro to produce a tissue similar to the impaired tissue seems tempting. It is transplantable into the defect and is tough to restore the defective surface completely. This is the intention of numerous scientific investigations concerning chondrocyte application to cartilage defects. Transplantation of isolated chondrocytes is currently used in clinical trials also. The possibilities and limitations of this technique are discussed including the fundamental principles and our own experimental investigations. A proof for the reproduction of a tissue similar to native cartilage with its typical long term mechanical properties is still missing. Further laboratory and clinical studies should be conducted before the technique is propagated in patient care.

Animals↗