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Biomedical subjects

H Mittelmeier

Publications and source records attributed to H Mittelmeier.

At least 19 recordsLinked to original sources
PubMed1998

[Pyrost, a spongious, mineral bone substitute. Experimental bases and 13-year clinical experience in over 1000 cases].

In different animal investigations Pyrost demonstrated osteoconductive and osteostimulative effects. In ectopic tissues and especially in conditions of low osteogenetic potency, the combination of Pyrost and autogenic bone marrow effects bone formation. In a clinical prospective study, Pyrost was implanted in 1117 cases in the following indications: Donor site defects after bone transplantation, bone defects after tumor resection, revision of THA, acetabuloplasty, fracture treatment, pseudarthrosis and lengthening osteotomy, spondylodesis. In 87.3% the regeneration of the bone defects was complete, in 8% a partial regeneration was found. Excessive bone formation took place in 2.7%, insufficient regeneration in 2.0% in cases of instability or infection. According to the clinical results Pyrost is a suitable bone substitute in small bone defects and it is a valuable completion to the autogenic bone graft in large defects. In disadvantageous bone bed Pyrost has to be augmented with bone marrow and in large segmental defects the combination with autogenic bone grafts is recommendable. Presupposition for the application of bone substitutes like Pyrost in large defects is a sufficient primary stability of the bone bed. The application in infected tissue is not favorable.

Animals↗
PubMed1996

Combined acetabuloplasty and varus derotation osteotomy in congenital dislocation of the hip. Long-term results.

Twenty-two patients (33 hips) with congenital dislocation of the hip were examined at an average of 26 years after combined acetabuloplasty and intertrochanteric varus derotation osteotomy. Seventeen patients had no problems despite physically demanding jobs and sporting activities in some cases. The CE angle was improved to the lower end of the normal range. The shaft-neck angle was corrected by 31 degrees to 120 degrees. Restoration to the normal valgus subsequently occurred and we found no evidence of subcapital coxa valga. Although there was an increase in the neck epiphysis angle 5 years after operation indicating a horizontal shift in the epiphyseal plate, most cases had normal hip joints. The incidence of postoperative avascular necrosis of the femoral head was 6%, and we found no increase in femoral deformities. Our long-term results show that the combination of acetabuloplasty and femoral osteotomy has no disadvantages, and is the best way of achieving optimal centring of the femoral head and stabilisation of the hip.

Acetabulum↗
PubMed1996

Radiographic course after acetabuloplasty and femoral osteotomy in hip dysplasia.

The radiographic course of 101 hips with residual dysplasia treated with roof plasty combined with intertrochanteric varus derotation osteotomy using the osteotomy wedge as a roof graft after Mittelmeier were reviewed. The average followup period was 8.8 years. The acetabular angle was improved by an average of 16 degrees (postoperative mean, 19 degrees; average at followup, 18 degrees). The center edge angle also was improved by 16 degrees and was stable at 25 degrees average at followup. The neck shaft angle, abnormal in 70% of hips preoperatively, was reduced by the varus osteotomies to a mean of 111 degrees and showed a spontaneous postoperative increase to normal values of an average of 129 degrees. There was no correlation of the postoperative of the neck shaft angle to patient age, preoperative valgus extension, correction angle, or length of followup. In nearly all cases, an almost anatomic joint shape was achieved. With a complication rate of only 1%, especially regarding the rate of necroses of the femoral head, the presented surgical technique can be recommended as highly effective, reliable, and safe for the treatment of congenital hip dislocation.

Acetabulum↗
PubMed1995

[Ischemia of the extremity as a rare complication of alloplastic joint replacement].

Two cases of extremity ischemia after alloplastic knee and hip joint replacement are presented. In both cases early operative intervention led to complete recovery. The mechanisms of iatrogenic vascular injury following arthroplastic operations on the hip and knee joint are demonstrated. In particular, the importance of preexisting vascular occlusive disease is stressed. Diagnostic procedures and implications for treatment are discussed.

Aged↗
PubMed1992

Sixteen-years' experience with ceramic hip prostheses.

The introduction of alumina ceramic combined with the self-locking principle by surface increase has many followers. There is no manufacturing company in the world that does not produce self-locking hip prostheses with ceramic components. Despite increased interim results with conventional prostheses by improved cement technique, the self-locking principle with wear resistant ceramic components is better, at least in young, active patients.

Adolescent↗
PubMed1989

["Elastic osteosynthesis" with autocompression plates of carbon fiber reinforced thermoplastic material].

The problem of atrophic bone that occurs in osteosynthesis employing rigid plates is first depicted. Attempts at fabricating "simirigid" plates, which, however, have so far failed to gain any practical importance are then discussed. The reason for this seems to be that made of duroplastics cannot be molded during the operation and the thermoplastics do not have sufficient strength. The production of semirigid plates made of thermoplastic Polyethersulfon (PES), reinforced with 20% short carbon fibres, results in plates which are made moldable by heating in a small oven, white retaining sufficient static strength, although only limited fatigue strength. Biomechanical examinations revealed that with appropriate dimensioning of the plates, "elastic osteosynthesis" results in less loss of mechanical function of the stabilized bones, so that less atrophy of the bone may be expected. During more pronounced exercise loading, a reversible "springiness" of the fracture results, which might stimulate callus formation and improved stability.

Bone Plates↗
PubMed1989

[Spongiosa formation in plate osteosynthesis--a comparative animal experiment study of current and auto-compression plates using the Zespol principle].

Osteosynthesis with modern self-contracting plates has a few fundamental drawbacks apart from its undisputably good points. Among these drawbacks we have the pressure strain on the bone surface; the traction strain exercised by the screw thread in the bone; and, chiefly, spongiotisation and bone atrophy due to so-called stress protection. A new modification of this process, called Zespol, in which the plate is no longer fastened direct to the bone but is fastened floating over the bone surface to so-called platform screws, tries to solve these problems. In a comparative animal experiment tibial transverse osteotomies in the rabbit were treated by osteosynthesis using small fragmentary ACP and Zespol plates. In respect of healing of the fracture none of the two methods showed any advantage. Histological evaluation of the plated bone sections were characterised in both plate systems by increasing spongiotisation and bone atrophy that increased with the length of application. Degradation processes were about equal with both systems. A special feature with the Zespol animals was that the cleft originally existing between the plate and the bone was filled up with newly formed spongy and later cortical bone. Due to this process the original cortex layer lost its function and atrophied severely. After 12 to 18 weeks the bone surface had reached the lower side of the Zespol plate and there was contact by touch. This restored similar biomechanical conditions as those existing in conventional plates after this period.

Animals↗
PubMed1989

[Cause, prognosis and therapy of tibial pseudarthroses].

A report on surgical treatment of 75 pseudarthroses of the tibia, 64 cases of which could be followed up for assessing the treatment results. The majority of these were pseudarthroses due to infection or associated with atrophy, that is to say, cases that were difficult to treat. Stabilization was usually effected by osteosynthesis with autocompression plates; in the majority of cases autologous bone grafts were performed additionally. In 82.8% of the cases cure of the pseudarthrosis was achieved, in 68.8% already by first surgery. 7.8% of the patients refused further surgical treatment. 9.4% are still under treatment at the time of writing.

Adolescent↗
PubMed1988

[Initial clinical experiences with low molecular weight heparin in the prevention of thrombosis in orthopedic surgery].

This is a report on almost 10 years of experience with heparin prophylaxis in orthopaedic surgery, especially on the changeover from the high molecular heparin dihydergot used previously, to the low molecular heparin dihydergot (Embolex) while changing over at the same time from the previously well-tried and successful postoperative initiation of treatment to preoperative start of prophylaxis. Compared with the period before prophylaxis (1965-1977) with 24 fatal pulmonary embolisms, no fatal pulmonary embolisms have occurred in our hospital since prophylaxis was introduced (1978). Changeover to low molecular heparin with only one instead of three injections daily was fundamentally welcomed although preoperative onset of prophylaxis involved a considerable rise in afterbleeding complications. Hence we recently adopted the procedure of conducting prophylaxis with low molecular heparin (as was done previously with success using high molecular heparin) postoperatively; this resulted in a dramatic reduction of bleeding complications while protection against thrombosis is obviously clinically satisfactory. Postoperative initiation of prophylaxis is therefore recommended in case of major orthopaedic surgery.

Adolescent↗
PubMed1986

[Significance of early meniscectomy in the etiology of severe arthritis of the knee].

With reference to 3579 meniscectomies performed in our clinic during 18 years as well as to cases with severe knee damage treated by arthroplasty, arthrodesis or correction osteotomy and their aetiopathological analysis with regard to previously performed meniscectomies, the following conclusions are drawn: Earlier meniscectomies seem to occur relatively often (up to 20%) in clinical cases of severe destructive processes in the knee e.g. knee arthritis. With reference to 3579 meniscectomies performed in this period this number is very low (1.34%) and - under statistical aspects - therefore not essentially important. The analysis of the cases of our clinic operated on by means of plastics, arthrodesis or correction osteotomies showed, that an earlier meniscectomy was performed because of static axis faults. These axis deviations were the main reason not only for the meniscopathy but also for the further development of knee arthritis. Cases of severe knee arthritis, who could be referred to an earlier meniscectomy (traumatic lesion) without any deviation of the leg axis were very rare. The rarity of the development of a knee arthritis after meniscectomy seems to prove that evidently there is no disadvantage of the mainly performed total meniscectomy compared to the subtotal procedure.

Arthritis↗
PubMed1985

[Operative long-term results in delayed radius head dislocation in childhood].

Only some cases and no long term follow-ups are reported in literature concerning the problem of delayed luxations of the radial head in children. 21 cases (19 acquired and 2 inherited) were treated in our hospital by operative procedure 12.5 months after the accident on the average. Disregarding one early and one late resection of the radial head we reconstructed the joint reposition and annular ligament plasty and if necessary correction osteotomy of the ulnar or shortening of the radius. Follow-up examination took place between 2 and 16 years after the operation, 7.9 years on the average. A reluxation was observed in 2 cases, a subluxation in 1 case. 2 patients showed a wrong axis and 4 patients signs of a beginning radio-humeral arthrosis, but most results were good or satisfactory. Therefore a reconstruction of a luxation of the radial head in children is recommended in delayed cases (sometimes in combination with a correction osteotomy of the ulna or radius) in contrast to other authors.

Adolescent↗
PubMed1985

[Causes of rearthrotomies of the knee joint].

Report on 178 rearthrotomies of the knee joint in 158 patients. Most of these rearthrotomies became necessary subsequent to meniscus operations. A review of the literature shows that these are mainly persisting or recurring complaints appearing usually under the overall pattern of "irritable knee". The principal causes were found to be leftover meniscus residues; on rarer occasions degenerative meniscus regenerates were found, or other causes such as floating cartilage, damaged cartilage of the patella, and instabilities of the condyles and of the ligaments.

Adolescent↗