Rheumatoid Forefoot

- Discussion:
    - the metatarsophalangeal joints are the most commonly affected portion of the rheumatoid foot
    - typical forefoot deformities are hallux valgus, hyperextension of MP joints, and flexion deformities of the IP joints of the lesser toes;
    - hyperpronation of rheumatoid foot:
    - MTP dislocation:
           - results from stretching of the volar plate and joint capsule;
    - metatarsalgia
           - plantar fat pad migrates distally with the toes;
           - loss of effectiveness of plantar fat pad causes painful plantar callosities to develop under the metatarsal heads, & w/ flexion of IP joints dorsal
                   callosities form because of shoe pressure;
    - hallux valgus:
    - claw toes
           - often involves claw toe or hammer toe of the lateral four toes, severe hallux valgus, and plantar keratosis beneath subluxed or dislocated MTP joint;
           - following dislocation of the MTP joints, long flexor tendons are displaced into the IM spaces which convertes them to MTP extensors;
           - w/ dorsal subluxation of the the MTP joints, there is increased tension of the long flexors, leading to MTP extension and secondary PIP joint flexion contractures;
    - asssociated conditions:
           - peripheral neuropathy
           - vasculitis
           - raynaud phenomenon:

- Physical Exam:
    - Acute:
            - nonspecific forefoot swelling
            - MTP joint tenderness
            - bursal enlargement
            - rheumatoid nodules
    - Chronic:
            - hallux valgus
            - clawing of the lesser toes with dorsal corns (fixed MTP hyperextension);
            - MTP joint dislocation;
            - plantar keratoses
            - metatarsal head prominence and atrophy of the fat pad;

- Radiographs:
    - first MTP joint space narrowing (from arthritis);
    - lesser MTP joint narrowing often indicates joint subluxation;
    - periarticular osteopenia;

- Non Operative Treatment:
       - see: orthotics for the foot:
       - mild deformity:
            - metatarsal arch supports, and soft soled shoes or rocker bottom shoes;
            - if hammer toes are present, then an extra depth shoe w/ Plastazote line may be necessary;
            - plastazote inserts will redistribute pressure bearing areas;
            - consider rubber backing of the plastizote sole;
       - moderate deformity: depth inlay shoe w/ thermoplast;
       - severe deformity: custom molded shoe may be the only option;

- Indications for Surgery:
    - pain which does not respond to inserts and medications;
    - progressive deformity;
    - 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);

- Surgical Treatment:
     - need to realign metatarsals & phalanges & restoration of adequate padding on the plantaar surface of foot, & correction of 
                  deformed position of IP joints;
     - hallux valgus deformity:
           - first MTP fusion:
                  - procedure of choice for hallux valgus in rheumatoid foot because it butresses the other toes;
                  - this is usually required in conjuction with metatarsal head resection and lesser toe correction;
                  - amount of bone resected from the 1st metatarsal head depends on the amount of shortening of the 2nd metatarsal region (the end of the 1st metatarsal
                          should be slightly longer than 2nd metatarsal);
     - lesser toe deformities:
           - IP joint involvement is addressed w/ resection arthroplasty or arthrodesis;
           - hoffman procedure:
                  - excision of the metatarsal heads thru plantar incision) or metatarsal head trimming or resection thru a dorsal incision w/ or w/o excision
                           of all or part of the proximal phalanx may resolve the symptoms;
           - dwyer procedure:
                  - excision of the lateral four MT heads with 1st MTP and second thru fifth PIP fusions combined with interposition of divided 
                           extensor tendon at the second thru fifth MTP joints
           - misc:
                  - consider K wire fixation or webbing procedures;
                  - failure to stabilize lesser toes will cause them to individually become malaligned;
                  - webbing procedure:
                        - Y shaped incision is made between toes, and is closed in a manner to syndactylize the toes;
                  - fat pad:
                        - relocation of the plantar fat pad may be achieved by excising an elliptical segment of redundant plantar skin
                        - alternatively some feel that the fat pad can be left alone since the plantar fat pad relocates proximally after the restoration of MP joint malalignment;
     - outcomes:
           - in the report by Coughlin MJ (2000), the author followed 32 patients (47 feet) w/
                  severe rheumatoid forefoot deformities who underwent MTP fusion and 2nd-5th MTP resection arthroplasties;
                  - all first metatarsophalangeal joints had successfully fused at an average of seventy-four months;
                  - average postoperative hallux valgus angle was 20 degrees and the average postoperative angle subtended by the axes of the 
                          proximal phalanx and the metatarsal of the second ray (the MTP-2 angle) was 14 degrees;
                  - 132 (70 %) of the 188 lesser metatarsophalangeal joints were dislocated preoperatively, compared with 13 (7 %) postoperatively;
                  - result of the procedure (as rated subjectively by the patient) was excellent for twenty-three feet, good for twenty-two, and fair for two;
                  - postoperative pain was rated as absent in eighteen feet, mild in twenty-five, moderate in four, and severe in none;
                  - rate of metatarsalgia  was low (6 %)  which was attributable to the increased wt-bearing on the first ray, which diminished lateral translation pressure beneath the lesser metatarsals
                  - Rheumatoid forefoot reconstruction. A long-term follow-up study.

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.

Surgical treatment for mild deformities of the rheumatoid forefoot by partial phalangectomy and syndactylization.

Treatment of painful subluxation or dislocation at the second and third metatarsophalangeal joints by partial proximal phalanx excision and subtotal webbing.

Forefoot surgery in rheumatoid arthritis: subjective assessment of outcome.

Failure of hallux MP preservation surgery for rheumatoid arthritis.

Original Text by Clifford R. Wheeless, III, MD.

Last updated by Data Trace Staff on Wednesday, May 30, 2012 3:16 pm