The ESKA femoral neck endoprosthesis (CUT) is a mini endoprosthesis anchored in the metaphysis for surgical management of young arthrosis patients with good bone quality. The necessary surgical intervention can be considered minimally invasive and adequate because only the affected femoral head is removed. The preserved femoral neck is used for fixation of the endoprosthesis to obtain proximal physiological force transmission and avoid stress shielding. Since the diaphyseal marrow cavity is not opened, the procedures entail decidedly less blood loss. Should the need arise to change the endoprosthesis, an endoprosthetic stem anchored in the diaphysis can easily be implanted after resection of the femoral neck near the base.

In endoprosthetics alumina ceramic femoral heads have been established for many years and their outstanding wear characteristics are scientifically proven. The taper connection between the hard but brittle ceramic head and the metallic stem must be performed by the operating surgeon intraoperatively. Thereby it is left to the surgeon to interpret imprecise and strongly deviating instructions given from manufacturer to manufacturer. This study clarifies the enormously large variations of interpretation in the clinical everyday life based on interviews and force measurements during handling when assembling. In comparable situations the axial cone setting forces, applied by a total of 39 operating surgeons from German hospitals, varied between 273 N and 7848 N. An additional coupling strength examination in the laboratory shows that torque loadings necessary for loosening several cone connection designs are in the range of those occurring under usual in vivo situations. This leads to the conclusion that for low-force-connected cone tapers joint friction of the artificial hip joint can cause a rotation and thus a loosening of the ceramic head of the implant neck during everyday activities. The authors proclaim the urgent necessity for clear handling references and the supply of a reproducibly safe taper lock method.

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While the principle of enlarging the surface area has been recognized and used in different ways for some time, there is often no schematic, detailed description or fundamental research. Taking a surface structure consisting of trabecular three-dimensional connecting elements, essential parameters are shown, making it clear that the flexible dynamic reaction of the effective "anchoring space" with a suitable specified shape (construction height, alignment, network) can be reproducibly shaped and used. This has led to a hip endoprosthesis with a graduated surface structure. The construction height of the trabecular structure varies, decreasing from proximal to distal.

The abductor apparatus (gluteal muscles and fascia lata) and the superior gluteal nerve remain intact. Immediate lateral positioning is allowed after surgery. The scar is unremarkable.

Increasing age and a higher level of mobility lead to an increasing incidence in revision arthroplasty after total knee replacement and tumor surgery. So far, the reconstruction of large defects in bony and soft tissue environments can be accomplished by the modern modular components of revision implants. The consecutive reconstruction of the extensor mechanism in extended revision has its own drawbacks and is often associated with significant functional limitations for the patient. Specially designed implants and methods are required to generate good functional results. The modular knee revision system MML provides specific modifications of the tibial component for reconstruction of the extensor mechanism. Combined with artificial strips, an excellent functional outcome could be achieved. In this study, 70 patients were operated with the MML endoprosthesis in knee revision or tumor surgery. An excellent functional outcome could be determined. At 7 years after surgery, an average of 32+/-13 points was achieved on the Oxford Knee Score. The outcome measurement using the functional scoring system of the American Knee Society (AKS score) showed similarly good results with 71+/-25 points out of 100. A minor deficit of only 2 degrees in active extension could be observed after reconstruction of the extensor mechanism. In conclusion, we have demonstrated that the MML modular revision system is appropriate for reconstruction of segmental bone defects.

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Background: As a result of numerous failed implantations of cemented ankle prostheses since the early 70s, ankle arthrodesis represented the "gold standard" in the treatment of ankle arthrosis. Due to a change to cementless implantations in the 90s it came to a remarkable reduction in early loosening, bone necrosis and sintering of the prosthesis which were the main reasons for former failures. In cooperation with ESKA Implants, Lübeck, we have developed a cementless anatomic ankle prosthesis. Patients and Methods: At our hospital, the ESKA prosthesis has been implanted in 56 patients (72% posttraumatic) since 1990. In our study, we report the examination results of 40 out of these 56 patients at least 1 year post implantation (21 of them more than 5 years). For evaluation, we used the Kofoed ankle score, which allows an easier comparison with other studies. This score showed an average improvement from 34.75 points preoperatively to 91.25 points postoperatively. Results: The persistent preoperative pain had completely disappeared in all patients; only twelve patients complained of intermittent pain under fairly heavy loading. 23 patients were able to walk > 2 km and 13 > 5 km without pain. The overall range of motion was 40-60° in 14 patients, 25-40° in 21, and < 25° in only five. We did not see any kind of secondary arthrosis in the adjacent joints. An arthrodesis which posed no problems had to be performed only three times: in two cases in 1991, during the 1st postoperative year, with both patients showing infections of the prosthesis; in the third case, the prosthesis had to be changed after 9 years.Conclusions: According to our good results and those of other studies on cementless ankle prostheses, we consider a cementless upper ankle prosthesis, implanted by a highly experienced surgeon, the preferable alternative to upper ankle arthrodesis.