Background: The long-term results for uncemented hip arthroplasty have not yet been sufficiently documented for a period of more than 15 years.

Methods: A clinical, phone, and radiological check-up with a mean follow-up of 15 (15–17) years analyzes the clinical results, the rate of aseptic loosening, the survival rate of the prosthesis, and the necessary re-interventions for a group of 320 consecutive total hip surgeries using Zweymüller screw cups and Zweymüller-SL stems in 303 patients from the years 1988 and 1989. The surgery was performed on 183 hips in women and 137 hips in men; 17 patients were operated on both sides. The mean age at the time of operation was 67 (29–99) years. All patients were permitted to put full stress on the leg immediately after the operation, and the prosthesis system was used as universal implant, no matter what the bone quality and the patient’s age. 164 (51.3%) of the hip patients had died at the time of the follow-up examination. Clinical and radiological examinations were available for 97 (30.3%) of the hips, phone interviews and radiological examinations for 4 (1.3%) of the hips, and phone follow-ups for only 49 (15.3%) of the hips. 6 (1.9%) of the hips were assessed as lost to follow-up.

Results: The Harris hip score results in a mean value of 88. The rate of aseptic loosening is 2% for the acetabular component and 1% for the femoral component. The stem and the cup had a survival rate of 98% in the surviving patients each. In 97.8% of the implanted prostheses, no exchange of a prosthesis component became necessary; in 95.2% of the patients, no operative revision of any kind was required.

Conclusions: With the Zweymüller hip endoprosthesis, excellent long-term results can be achieved both from a clinical perspective and regarding the rate of aseptic loosening and the survival rate. The system can be fully stressed immediately after the operation; age and poor bone quality are not contraindications for an implantation.

The standard treatment of arthrosis of the ankle joint is arthrodesis while new prosthesis leed to good clinical results. Currently there is much controversial discussion, and knowledge of the fundamentals of biomechanics is becoming ever more important.

Ten macroscopically and roentgenographically normal foot specimens were tested comparing tibio-talar arthodesis vs. nativ situation on a kinematic gait simulator. The stance- phase of normal walking gait was simulated from heel-contact to toe-off. Ground reaction forces were simulated by a tilting angle- and force-controlled translation stage upon which a pressure measuring platform was mounted. Force was applied to the tendons of the foot flexor and extensor muscle groups by cables attached to an additional set of six force-controlled hydraulic cylinders. Tibial rotation was produced by an electrical servo motor.

The change after arthrodesis was a varying degree of relocation of average force and maximum pressure from the lateral onto the medial column of the foot; the increase force on talonavicular joint and decrease on calcaneocuboid joint is statistically significant. The average force increased from native 66.7N to 80.8N upon arthrodesis in the talonavicular joint and decreased in the calcaneocuboid joint from 71.9N to 58.5N. Peak pressure increased from 3728kPa to 4552kPa in talonavicular joint and decreased in calcaneocuboid joint from 3809kPa to 3627kPa. After arthrodesis, we measured inconsistent changes in Chopart joint. On some feet, the changes in stress were slight, but on majority, relocation of force and peak pressure was significant. The result was a change in the function of Chopart joint with increased extension load on talonavicular joint at time of highest joint load during push-off.

These in vitro observations explain the clinical observations that have followed ankle arthrodesis. For one, there are reports on tibiotalar arthrodesis patients who are largely mobile and free of complaints, which correlates with the observation that not all preparations indicate a clear relocation of force and intraarticular peak pressure onto the talonavicular joint. In these cases, the ability of strong muscular plantar flexion could explain a good functional result. In contrast, and in addition to subtalar joint degeneration, arthroses in the talonavicular joint have been frequently observed following tibiotalar arthrodeses. The relocation of both force and intraarticular peak pressure onto the medial column of the foot in the majority of preparations explain the degeneration on the extensor side of the joint with osteophyte formation impressively.

The comparability of studies of extra-articular proximal femur fractures is compromised by the lack of a widely accepted, simple classification system with clinical and prognostic relevance. The aim of the study is to define the complication profile as well as differences relating to age, gender and survival rate of simple trochanteric fractures (typ 1), intertrochanteric comminute (typ 2) and subtrochanteric fractures (typ 3).

The records of 335 consecutive patients were analysed prospectively. Patients had a mean follow-up of 10 (0–56) months, and were treated operatively with three intramedullary nailing systems.

Simple trochanteric fractures (n=67) show only wound healing problems (1.5%). Median age is m/f 76.4(45–98) years/82.7(39–101), and the two-year survival rate is m/f 50.3%/84.9%. Intertrochanteric comminute fractures (n=204) demonstrate the highest complication rates (25%) with 9.7% femur head perforations, 3.5% other hardware related problems and 11.8% wound healing problems. Median age is m/f 72.5(41–94) years/83.6(54–100), survival rate is m/f 92.7%/66.5%. We observe a complication rate of 17.0% in subtrochanteric fractures (n=64), no femur head perforation but 9.1 % other hardware problems and 7.8% wound healing problems. Median age is m/f 61.1(24–91) years/81.6(38–99), surviving rate is m/f 92.3%/67.9%. The overall complication rate is nearly twice as high in females compared to males (19% versus 10%).

The 3 types of proximal extraarticular femur fractures show diferrences in epidemiological data such as median age and surviving rates. Furthermore intramedullary nail osteosynthesis of extraarticular proximal femur fractures lead to different complication patterns in simple trochanteric fractures, in comparison to inter-trochanteric comminuted fractures and subtrochanteric fractures. The recommended surgical treatment in Type 1 fractures leads to a low complication rate. Type 3 fractures exhibit an acceptable complication level; pseudarthrosis and intraoperative shaft fissures as well as wound healings problems are the main complications. Type 2 fractures represent fractures whose treatment is problematic, with the highest complication rate of hardware-related problems (13.2%), including femoral head perforation (9.7%), and the highest number of wound healing complications (11.8%), more than a third of which are infections.