Purpose and background:

Sacroiliitis identified by MRI is considered as a keystone in the diagnosis of spondyloarthritis. To reduce the number of unnecessary MRI scans it would be ideal if sacroiliac (SI) joint pain provocation tests could be used to identify patients at risk of having sacroiliitis.

The aim of the current study was to investigate the diagnostic value of three pain provocation SI-joint tests for sacroiliitis identified by MRI.

Background

The outcome of studies on back pain is usually measured at specific intervals (1 month, 3 months, etc.) However, because LBP is a recurring condition it would be more relevant to identify outcome in relation to course over time. A new data collection tool was recently developed (SMS-Track), allowing this to be done.

We studied the tapered interface between the head and the neck of 139 modular femoral components of hip prostheses which had been removed for a variety of reasons. In 91 the same alloy had been used for the head and the stem; none of them showed evidence of corrosion. In contrast, there was definite corrosion in 25 of the 48 prostheses in which the stem was of titanium alloy and the head of cobalt-chrome. This corrosion was time-dependent: no specimens were corroded after less than nine months in the body, but all which had been in place for more than 40 months were damaged. We discuss the factors which may influence the rate of these changes and present evidence that they were due to galvanically-accelerated crevice corrosion, which was undetected in previous laboratory testing of this type of prosthesis.