Purpose of the study: The accuracy, reproducibility and concordance of wear measurements made with the Imagika system were tested on knee prostheses.

Material and methods: Anteroposterior radiographic images of implants with tibial inserts measuring 9, 7, and 11 mm thick were obtained, the tibial base had a 28 mm bead for calibration. The ap images were digitalized and variations in incidence were controlled with a plumb line. Combining the tilt positions from −10° to +10° and rotation from −5° to +5°, a total of 132 images were obtained. Four groups were defined according to tilt and rotation (±5°, ±3°). The images were read by to observers. Reproducibility and agreement were assessed for the overall series and for each of the four groups. Two images were read 40 times by the same observer using variable digital quality (100–300dpi) to determine measurement accuracy and error. Results were compared with the manufacturer’s data sheet.

Results: Measurement agreement was poor in the four groups. Reproducibility was excellent at the 1% threshold for the overall series and for groups 3 and 4 for both observers. The accuracy improved from 0.6 to 0.5 mm by improving digitalization from 100 to 300 dpi with an error to the order of 0.05. Guiding the points used by the software for measurements, the accuracy could be improved to 0.25mm. The difference between the lateral plateau and the medial plateau appeared for the lesser tilt and for rotation greater than 2°. The thickness displayed was close only for the groups with little tilt.

Discussion: The reproducibility and accuracy of the Imagika system can be brought below the 0.5 mm threshold. For views without tilt, the difference compared with the displayed values varied from 0.1 to 0.3mm. The agreement remains poor if the position of the measurement points is not predefined by the system.

Conclusion: Offering an excellent reproducibility and good accuracy, the Imagika system enables monitoring TKA wear if the incidence of the radiographic images is perfectly controlled. For a more quantitative approach, the calibration method would have to be improved.

This retrospective study of 196 cases of children’s elbow dislocation had for objectives to check literature’s epidemiological data and to compare the various therapeutic protocols used over a 32 years period.

The average age was 11 years, boys (117) were more frequently affected than girls (79). Both sides were almost equally affected. Most dislocations were posterior or postero-lateral (176). An associated fracture has been found in 104 cases, in 64 cases it was a medial epicondyle’s fracture. Nervous or vascular complications have been found in 8 cases and have immediately been reversed following reduction of the dislocation.

153 patients have been reviewed, 134 patients reported good results, 12 results were average and 7 results were poor. Radiological calcifications have been found in 37 cases (24%). We have shown significant statistical link between the occurrence of elbow stiffness and 2 factors: the carrying out of late kinesitherapy and the appearance of posttraumatic calcifications. We haven’t found any factor favoring the appearance of calcification.

This large series has confirmed the epidemiological data found in literature and allowed us to initiate a simple therapeutic stance combining an early reduction under general anesthesia, the carrying out of an osteosynthesis each time it is necessary and a plastered immobilization of 4 weeks followed by a self rehabilitation.