[Computer-assisted prosthesis selection and implantation control]. / Computergestützte Prothesenauswahl und Implantationskontrolle.

Using CT-based 3D-data of human femora, it is possible to simulate the THR very realistically by a newly developed fit program. The evaluation of OP simulations of different prostheses systems on more than 200 femora showed that a large number of hip joints can only be reconstructed unsatisfactorily by standard stems regarding intramedullary fit and joint geometry. This could be minimized by optimized off-the-shelf prostheses, but there is still a remainder that can only be satisfactorily reconstructed by customized devices. The decision of choosing a standard or custom device for each individual case can be made by the same fit program using CT-data of the femur. Planning with conventional X-rays only shows major restrictions. With the results of our evaluation, "standard stems" have been developed respecting the fixation principles of our CTX-custom device system and with optimized head positions using statistical methods. The selection of the right size regarding the criteria of fixation and joint geometry is examined preoperatively with the help of the same fit program. If standard prostheses cannot fulfill the requirements, we see the indication for a custom-made stem. In this way the quality of custom-made prostheses can be transferred to the application of standard devices. The operative results confirm our expectations of the exact planning and implantation technique. The CTX combination system consisting of off-the-shelf stems and customized devices will reduce the costs for optimized techniques. In comparison with other new 3D-methods like robotics or navigation, our development has an advantage: this technology including the fit program is accomplished preoperatively in order to simplify the operative technique. In future, combinations of our advanced planning methods as well as implantations of custom prostheses using navigation systems and/or robotics seem to be possible and may be helpful for special cases.

[Effect of a fibrin-antibiotic compound in bone and soft tissue infections]. / Zur Wirkung eines Fibrin-Antibiotikum-Verbundes bei Knochen- und Weichteil-Infektionen.

It is reported on experimental experiences in the use of a biological adhesive system--highly concentrated native fibrinogen, thrombin and clotting factor XIII--in conjunction with local antibiotics. The results in animals are: Antibiotics in conjunction with the mentioned adhesive system give a high local concentration for a short time. The activity of the antibiotics decreases quickly within some activity of the antibiotics decreases quickly within some hours, there is no more antibiotic effect after 36 hours.

[Long term results with a new lunate bone prosthesis]. / Langzeitergebnisse mit einer neuen Lunatum-Prothese.

In the University of Essen Orthopaedic Clinic a lunate prosthesis was developed. Three different sizes are available. The strongest indication for this prosthesis is complete destruction of the lunate. Advanced arthritis and heavy manual work are contraindications. Since 1974, fourteen prostheses have been implanted. Nine patients have been followed for an average of 2.1 years. Range of motion and strength of the wrist were reduced on the average of 50 percent. A higher proportion is free of pain despite evidence of progressive arthritis. This prosthesis may be a reasonable treatment modality for a problem without good therapeutic alternatives.

[The ulnar nerve compression syndrome]. / Die Ulnaris-Kompressions-Syndrome.

The ulnar nerve has to bear a large amount of compression, especially in the cubital tunnel, which can be deducted from the topographic relation of this nerve to the elbow. Apart from tightness of the tunnel, intraarticular changes can also cause compression of the nerve. A further narrow tunnel in the course of the ulnar nerve is the "loge de GUYON", situated in the hypothenar region. A careful neurological examination of sensory and motor signs as well as an accurate electromyographical examination differentiate compression syndromes from other neuropathies. Two unusual cases of a functional cubital tunnel syndrome are demonstrated: their cause was primarily a chondromatosis of the elbow joint in one case a functional vasal compression in the other case.