The overall purpose of this project is to investigate the neuro adaptations of pain and biomechanical differences between placebo and a custom-made foot orthoses for patients with RA.

Rheumatoid arthritis (RA) is an autoimmune, chronic, progressive, systemic inflammatory disease leading to substantial pain, disability, and other morbidities. In Denmark there are 40.000 patients with RA. In RA, synovitis, effusion, eventually erosive arthritis, bone loss and weakening of the muscle and tendon apparatus are thought to cause clinically recognizable valgus heel or pes planovalgus deformity. These symptoms gradually cause irreversible joint deformities and changes in the locomotion of muscles3. Over 85% of patients with RA experience painful feet and ankles during the course of the disease. Despite medical developments, foot orthotics (FO) are still an important adjunct treatment and are often prescribed with the intention to stabilize and align the foot. This is due to a number of reasons: 1) persistent foot and ankle problems still occuring even after clinical remission is reached. 2) patients with increased disease activity may have mechanical foot impairments that need treatment in conjunction with systemic management. and 3) patients, who have not responded to or are ineligible for biologic agents, continue to have active foot impairments. However, the scientific research literature within FO treatment has lagged behind clinical practice, often leading the clinician to recommend interventions based on opinion and past experience rather than published evidence9.

Production of FO is an enormous industry. Consequently, there is a great variety of products with different materials, design, manufacturing techniques and procedures. In the literature, some FO have been shown to reduce pain however there is a considerable amount for which the studies are either inconclusive or refute the effect of FO. This might be due to differences in methodology, sparse description of the orthotics and limited information on patient's disease type and stage. However, multidisciplinary studies are still limited and it is, therefore, too early to come up with guidelines about how these interventions affect the human body mechanically from current knowledge. Previous studies have primarily focused on how foot orthotics affect pain, foot function, walking speed, forefoot plantar pressure and gait parameters, while not considering the mechanical principles on which the rationales for FO were originally based. This has led to an abundance of clinical trials that are challenging to interpret, as FO clinical outcomes and FO gait mechanics have not been studied together.

Inclusion Criteria:

• Patients with RA (EUALAR 2010) without significant damage or with small erosions but without radiological subluxation in the feet, max Larsen rheumatoid arthritis score 224.
• With clinical (medical) assessed needs for orthotics (e.g. valgus ankle, pes planus, pes planus transversus, and metatarsophalangeal instability).
• In stable disease phase (no clinically recognizable, swollen joints (but sore joints)).
• In stable treatment (no change in DMARD, NSAIDs and steroid treatment the last 4 weeks).

Exclusion Criteria:

• • Patients with RA using, or regularly used FO, or orthopedic shoes within the last 3 months.

  • Clinically significant joint disease (inflammatory or degenerative) of the knee or hip joints (according to the clinician).
  • Clinically significant back disorder (according to the clinician).
  • Patients with severe ischemic or neurological sequelae in the lower extremities.
  • BMI above 32.
  • Not suitable for a MRI scan (e.g. pacemaker, pregnancy or metal within the body).