- Discussion:
- the foot is the initial manifestation of RA in 15% of patients;
- initially, RA involves the forefoot, then the midtarsal joints, and finally the hindfoot;
- forefoot is involved twice as often as the hindfoot;
- although forefoot & hindfoot disease can coexist, commonly pt's have one or the other;
- rheumatoid forefoot:
- hyperpronation of rheumatoid foot:
- metatarsalgia
- claw toes
- midfoot:
- talonavicular arthritis:
- these feet tend to collapse but are still correctable;
- consider fusion talonavicular joint to provide foot w/ stable medial beam & prevent calcaneus taking a fixed valgus position;
- this needs to be carried out at the first sign of midfoot hyperpronation, consider using iliac bone graft to ensure union;
- reference:
- Talonavicular arthrodesis for rheumatoid arthritis of the hindfoot.
- rheumatoid hindfoot:
- rupture of tibialis posterior:
- results in collapsed midfoot w/ forefoot abduction and hindfoot valgus;
- it is most difficult to manage of all RA foot problems;
- early features include, synovitis, pain, and diffuse swelling;
- early synovectomy of tendon sheath not only relieves discomfort but will possibly delay or prevent attenuation or rupture;
- when dx of ruptured posterior tibial tendon has been made, in the presence of correctable hyperpronation, transfer of
FDL tendon to distal posterior tibial tendon stump has been found to be acceptable;
- most commonly, disease affects posterior tibial tendon sheath, leading to valgus deformity and subluxation of the talonaviclar joint;
- Radiographs:
- radiographs may show soft tissue swelling, subchondral bone erosions, osteopenia, joint space narrowing, and bony destruction;
- measurement of the talocalcaneal angle (first TMT angle);
- Non Operative Rx:
- see: orthotics for the foot:
- shoe modification includes arch supports for posterior tibial tendinitis;
- loss of forefoot to hindfoot alignment should be compensated w/ orthotics;
- Surgical Considerations:
- some of the RA foot procedures are destructive and non-anatomic (such as the Hoffman procedure), and these types of procedures
should be performed late in the disease process (once it has largely runs its course);
- rheumatoid forefoot:
- forefoot surgery should consider problem of pain rather than function;
- rheumatoid hindfoot:
- selectivie fusion: talonavicular (high rate of non union) hyperpronation of rheumatoid foot:
- triple arthrodesis for advanced cases;
- wt bearing heel should be kept under load of the joint line of leg;
- mobile joints should be kept mobile wherever possible, unless their mobility is outside normal range, allowing collapse of foot archetecture;
- during gait body load line should pass forward thru foot w/o producing abnormal rotational forces in the foot
Arthrodesis of the first metatarsophalangeal joint for hallux valgus in rheumatoid arthritis.
Metatarsal head resection for rheumatoid deformities of the forefoot.
Surgery of the forepart of the foot in rheumatoid arthritis.
Forefoot surgery in rheumatoid arthritis: subjective assessment of outcome.