Table 1 Overview of MSUS Scanning Protocol

1.

The nature of the test was explained

2.

The forefeet of all participants were scanned by the investigator using a broadband linear probe of 5 – 10 MHz frequency.

3.

The participant was asked to sit in a supine position on the bed.

4.

The participant's hosiery was removed and the ultrasound probe placed on the plantar aspect of each foot.

5.

Scans were taken according to the EULAR standard approach from the plantar aspect of the foot [14].

6.

Each MTP joint and inter-metatarsal space was scanned longitudinally and transversely from the plantar view.

7.

Images of the plantar aspects of the forefoot in both feet were recorded in transverse and longitudinal aspects and saved on the ultrasound machine hard drive.

8.

Observations of synovitis and erosions of the second and fifth metatarsophalangeal joints and any evidence of bursitis were noted on a separate data collection sheet.