The rheumatoid forefoot : surgical treatment and epidemiological aspects

Abstract

Background: The forefoot is frequently involved in rheumatoid arthritis (RA) resulting in a painful, handicapping deformity. The prevalence stated has long been based on a study from 1956. The most common surgical treatment has been a resection of the metatarsal joints (MTP), initially effective but often connected to recurrence of pain and deformity. Fusion instead of resection in MTP 1 seemed to produce better results. This operation is though technically more demanding. The aim of this thesis was to analyse and optimise the operative technique for fusion in MTP 1, to compare it to Mayo resection in MTP 1 in a prospective, randomised manner and to investigate the frequency and impact of foot problems in patients with RA today.

Results: · A guide-plate may aid the positioning of the arthrodesis in recommended angles. The rounded cup and cone technique for preparation of the joint surfaces and two crossed cortical screws for fixation resulted in a high healing rate; · In comparing resection of MT heads 2 to 5 combined with either Mayo resection or fusion in MTP 1, after mean 3 years follow-up, we found excellent patient satisfaction rate, significant reduction of pain and handicap according to the Foot Function Index with no statistically significant differences between the groups. There were no recurrent prominences or tenderness under the forefoot in any group, no recurrent severe hallux valgus in the resection group and no increased risk for painful IP joint problems after fusion. The operating time was significant longer for fusion; · After mean 6 years follow-up, patient satisfaction rate was still excellent and the reduction in the parameters mentioned above was still significant with no differences between the methods. Gait velocity, step length, plantar moment, mean pressure or position of centre of force under the forefoot, measured in half of the patients. did not differ significantly either. Cadence (steps/min) was higher and stance phase (ground contact time) shorter in the fusion group; and · In a study of 1000 RA patients, 80 %reported current foot problems, of which 86 %in the forefoot. In 45 % the forefoot had been involved in the debut of the disease. Difficulty in walking due to the feet was declared in 71 %. For 41 % the foot was the most important part and for 32 % the only part in the lower extremity causing reduced walking capacity.

Conclusions: The positioning of a fusion in MTP 1 may be facilitated by the use of a guide plate. Careful preparation and fixation lead to a high healing rate. In a prospective, randomised study, both fusion and Mayo resection in MTP 1 as part of a total rheumatoid forefoot reconstruction resulted in significant and lasting reduction of pain, handicap and deformity with no statistically significant differences between the groups. Load distribution under the forefoot and time-and distance gait data, measured after 6 years, did not differ either, except in cadence and stance phase, possibly as a sign of the loss of motion in MTP 1 after fusion. The foot is still, during active medical treatment today, next to the hand, the most frequently symptomatic joint complex in RA. In 1/4 of the cases the foot caused walking disability and was twice as often as the knee or hip the only joint impairing the gait.