[Arthrodesis vs. prosthesis for end-stage osteoarthritis of the ankle joint : A scientific argument]. / Arthrodese vs. Prothese bei endgradiger Arthrose am oberen Sprunggelenk : Ein Streitgespräch.

The gold standard in operative treatment of end-stage ankle osteoarthritis remains controversial even now. Endoprosthetic treatment, which has undergone significant improvements in recent years competes with arthrodesis, which can achieve excellent results particularly in the arthroscopically assisted technique. Both procedures offer specific advantages and disadvantages so that the decision about indications for treatment should always be made individually, taking specific needs and the individual constellation of findings of the patient into consideration.

Plate Positioning in Periprosthetic or Interprosthetic Femur Fractures With Stable Implants-A Biomechanical Study.

BACKGROUND: Angular stable plate fixation is a widely accepted treatment option for interprosthetic or periprosthetic femoral fractures with stable implants. This biomechanical study tries to establish a safe distance of the plate from the tip of a femoral prosthesis. METHODS: A total of 38 composite femurs were reamed to an inner diameter of 23 mm to create an osteoporotic bone model. A Weber hip stem was cemented into each and a distal femoral NCB plate applied with the distance to the stem varying from 8 cm apart to 6 cm overlap in 2-cm steps. Each specimen was tested in cyclic axial loading (400 N-1500 N) and then cyclic torsion (0.6 Nm-50 Nm). Peak strain on the femur around the tip of the plate was measured with a 3D image correlation system and averaged over 26 cycles (excluding the first 3 and the last cycles). Finally, each femur was axially loaded to failure. RESULTS: Strain increased with decreasing overlap or gap. Seven specimens failed early between 2-cm overlap and 2-cm gap. Results were divided into a far group with a distance of >4 cm and a close group of <4 cm. Strain was significantly higher in the close group for axial (P < .001) and torsional (P < .001) loading. Failure load was significantly lower in the close group (P = .002). CONCLUSION: A minimal gap and/or overlap of at least 6 cm is recommended in osteoporotic bone to avoid stress risers.