Page 72 - Imaging of Osteoarthritis and Rheumatoid Arthritis in Hand Joints
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                                Chapter 4
Twenty patients and two healthy controls were included in the study. In five patients, the trapezium was very deformed and could not be extracted without severely damaging the distal articular surface. We were therefore unable to obtain histological specimens from these patients. During histological analysis of the 15 specimens, we noticed that a considerable part of the articular surface was missing in the specimens of three patients. These patients were excluded from further analysis. The MRI scans of the excluded patients were used for training and calibration of the MRI score.
The final patient group therefore consisted of 12 patients; two were male and 10 were female, with an average age of 60 (range 46-77) years. The median number of days between MRI and surgery was 8 (range 1-39). Mean grip strength (SD) was 23 (11) kg, and mean pinch strength (SD) was 3.8 (0.9) kg. Self-reported pain assessed by visual analog score (possible range 0-100) varied widely between patients. The median (IQR) pain score at rest was 19 (5- 31), and the median pain score during thumb activity was 57 (37-67)
The image quality in eight out of our twelve patients was adequate or higher, but was low in the other four patients. All patients had one or more osteophytes at the trapezium. All but one patient had cysts and/or erosions on the trapezium, and seven out of twelve CMC1 joints were malaligned or subluxated. Overall cartilage damage was severe (table 1). All patients had at least one small area with full-thickness cartilage loss. Five out of twelve patients did not have any remaining area of cartilage of normal thickness. The median (IQR) surface area of trapezial cartilage damage was 98% (82%-100%). The percentage area with full-thickness cartilage loss was 43% (22%-70%). The image quality in both healthy controls was good, and they both had normal cartilage layers, without any damage.

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