THE ASSOCIATION OF RHEUMATOID ARTHRITIS AND NON-UNION OF TRAUMATIC FRACTURES

Abstract

Fracture repair is a wound healing process that in young healthy patients usually proceeds to uncomplicated union. However, the healing cascade is delayed with increasing age, medication and certain diseases such as rheumatoid arthritis.

Recently the important role of the immune system in fracture repair has become apparent within the emerging subject of Osteoimmunology. Patients with rheumatoid arthritis have an altered immune system and therefore we have investigated the hypothesis that patients with rheumatoid arthritis have a higher incidence of non-union after a fracture compared to patients without rheumatoid arthritis.

Method: The Edinburgh Royal Infirmary computer database was searched over a 10 year period (May 1996- May 2006) to identify all patients with non-union out of the total number of patients presenting with fractures. These patients groups were then subdivided into patients that had and did not have rheumatoid arthritis. Patients were excluded if they were lost to follow up, or if the fracture either occurred before the May 1996 or management continued passed May 2006. In this study non-union was defined as failure to heal within expected timescale and lack of progression at serial x-rays (all non-union were diagnosed at least 3 months from fracture).

Results: From May 1996 through to May 2006, 8,456 patients with fracture were defined. 71 of these patients with fractures had rheumatoid arthritis. Of these patients 63 had union of their fractures whilst 8 patients developed non-union of their fracture (11.3%). In a total of 8385 non rheumatoid arthritis patients 164 developed non-union of their fracture compared to 8221 patients who had union of their fractures (2%). Comparison between these two patient groups suggests rheumatoid arthritis patients are more likely to develop non-union of traumatic fractures (Chi squared test, p value < 0.001).

Patients with rheumatoid arthritis who progressed to non-union were on the following medication, Gold (1), Indomethacin (1), Non steroidal anti-inflammatories (4), Combination analgesia (2), Antihypertensives (2), Omeprazole (1) and Thyroxine (1).

Discussion: The results from this study suggest that patients with rheumatoid arthritis have a greater incidence of non-union after a fracture compared to patients without rheumatoid arthritis. This maybe due to the abnormal immune system in rheumatoid arthritis patients. However rheumatoid arthritis patients are often on a number of medications and these drugs rather than the innate alteration of the immune system may be responsible for the altered healthy response. However whether as a result of the rheumatoid arthritis itself or the medication, our study demonstrates a higher non-union rate in the rheumatoid arthritis patients and this needs to be taken into account when treating rheumatoid arthritis patients with fractures.