For patients with rheumatoid arthritis in the feet, the common symptom of ‘walking on marbles’ is an agonizing one. Forefeet often contain some of the first joints to be affected by RA and those with the condition often say that they feel like they are ‘walking on marbles’. Mostly, people have thought that this was due to walking on foot joints that are affected by the RA.

But researchers at the University of Southampton in England are about to begin a new stage of a study aimed at improving the health and mobility of those suffering from walking on marbles.

The Health Sciences’ FeeTURA study has developed new ways of assessing the forefeet through the use of diagnostic ultrasound and magnetic resonance imaging techniques. From this work, the team discovered that some of the swellings and associated feeling of ‘walking on marbles’ were related to inflamed bursae (a fluid-filled sac usually found in areas subject to friction) that had developed underneath the forefoot joints. These inflamed bursae were rarely detected by clinical examination.

Though the exact cause of the inflamed bursae is not known and a cure has not yet been found, the team is now looking at identifying inflammatory and mechanical markers to find the best ways of treating this complication in patients suffering with RA. They will evaluate foot health treatments, such as targeted steroid injections, as well as medical management through the use of new drugs (called biologics).

During the first stage of the study, which took place between 2006 and 2009, researchers at the University of Southampton developed a technique to better evaluate the forefeet and diagnose the ‘marbles’ using diagnostic ultrasound. Participants who were assessed at the NIHR Wellcome Trust Clinical Research Facility (WTCRF), based at Southampton General Hospital, returned for re-assessment in the second stage of the study which discovered the changes that had occurred in the condition. A third stage used an MRI scan to visualize the anatomical structures and ‘marbles’ more clearly in the forefeet and resulted in researchers developing the first ever atlas to categorize the swellings originally identified in stage one.

Here at Arizona Bone and Joint Specialists, many patients’ feet often contain some of the first joints to be affected with rheumatoid arthritis. Common symptoms are foot stiffness, swelling, loss of flexibility, joint deformity, and foot discomfort. Besides complaining that they feel like they are ‘walking on marbles’, some also say that it feels as if ‘they have a pebble in their shoe’.

Inflammation caused by RA may weaken the structures in patients’ feet, making them more vulnerable to the stresses endured during standing and walking (weight bearing). This inflammation can cause the normal arches of the foot to flatten, and in turn alter normal walking patterns. The metatarsophalangeal joints (the balls of the feet) are usually the first joints of the foot to be affected. When this portion of the foot is involved, forefoot may spread out, the joints across the ball of the foot may “drop”, and the fat pads on the bottom of the feet can shift. These changes in the feet decrease the amount of protection on the ball of the foot, and may make standing very painful. Bunions, overlapping toes, hammer toes (when the toes curl under), and cock-up toes (when the toes lift up) can also be the result of these foot changes.

The advice and information contained in this article is for educational purposes only, and is not intended to replace or counter a physician’s advice or judgment. Please always consult your physician before taking any advice learned here or in any other educational medical material.