DEFINITION

Rheumatoid arthritis is an inflammatory condition of synovial joints that usually presents as a symmetric polyarthropathy.

Ninety percent of patients with chronic rheumatoid arthritis have involvement of the foot; the forefoot is the most commonly involved area of the foot.

 

 

ANATOMY

 

The metatarsophalangeal (MTP) joint of the foot is stabilized by the plantar plate, the collateral ligaments, the capsule, and a dynamic balance between the intrinsic and extrinsic muscles of the foot.

 

The intrinsic muscles are plantar to the MTP joint axis and help to plantarflex the joint.

 

 

The proximal phalanx of the hallux has a valgus orientation of 0 to 15 degrees at the MTP joint. A plantar fat pad normally provides cushioning and protection for the metatarsal heads.

PATHOGENESIS

 

Unrelenting synovitis leads to a painful and swollen joint. This causes a stretching of the ligamentous structures surrounding the MTP joint.

 

Ligament stretching combined with forces of walking leads to soft tissue instability, articular cartilage destruction, and subchondral bone resorption.

 

Residual laxity leads to subluxation and dislocation of the lesser MTP joints. This allows the metatarsal head to protrude through the plantar plate and capsule.

 

The hallux most commonly develops a hallux valgus deformity, with an occasional hallux varus developing.

 

MTP instability leads to intrinsic muscles becoming dorsal to the MTP axis, which leads to loss of active MTP flexion and interphalangeal extension. This leads to a claw toe deformity.

 

Dislocation of the metatarsal lesser MTP joints leads to a distal migration of the fat pad, which exposes the metatarsal heads, increasing pressure in this area.

 

NATURAL HISTORY

 

Rheumatoid arthritis initially presents in the foot in about 17% of patients.

 

It is a progressive disorder that may start as synovitis and progress to dislocations and degeneration of the joint.

 

The longer active rheumatoid disease is present, the greater the likelihood the patient will develop deformities as a result of the associated synovitis.

 

PATIENT HISTORY AND PHYSICAL FINDINGS

 

Initially, patients often complain of an insidious onset of poorly defined forefoot pain and difficulty with ambulation. As synovitis leads to deformity within the forefoot, the symptoms then become more localized.

 

Patients will often have shoe wear-related irritation along the medial eminence of the hallux and along the dorsal aspects of the proximal interphalangeal (PIP) joints of the lesser toes.

 

With the development of the lesser toe MTP dislocation, pain on the plantar aspect of the metatarsal heads is present.

 

Hallux valgus: The examiner should look for the degrees of valgus orientation and its impingement on lesser toes. Patients often have pain along the medial eminence and from pressure on the toes (FIG 1).

 

Lesser MTP dislocation and plantar callus: The examiner should inspect and palpate the dorsal and plantar aspects of the forefoot. MTP instability can vary from subluxation to dislocation. Increased pressure under the metatarsal heads is a common source of pain (FIG 2).

 

 

Examination should include range of motion for the ankle, subtalar, and MTP joints.

 

The examiner should perform a complete vascular and neurologic examination of the foot.

 

IMAGING AND OTHER DIAGNOSTIC STUDIES

 

Plain radiographs will often show periarticular osteopenia, symmetric joint space narrowing, marginal cortical erosions, and subchondral cysts (FIG 3).

 

The severity of hallux valgus and the presence of MTP dislocation can be evaluated.

 

 

 

FIG 1 • Hallux valgus: The examiner should inspect the foot with the patient standing.

 

 

41

 

 

 

 

FIG 2 • Lesser MTP dislocation and plantar callus: The examiner should inspect and palpate the dorsal and plantar aspects of the forefoot.

 

DIFFERENTIAL DIAGNOSIS

Inflammatory arthritides such as psoriatic arthritis, Reiter syndrome (reactive arthritis), and ankylosing spondylitis

Gout and pseudogout

Connective tissue disorders (ie, lupus)

Inflammatory bowel disease (Crohn disease or ulcerative colitis) Neurologic disorders

Osteoarthritis

 

 

NONOPERATIVE MANAGEMENT

 

New pharmacologic agents that can control synovitis have the potential for minimizing the severity and frequency of deformities seen.

 

 

Shoe wear modifications such as extra-depth shoes decrease shoe wear irritation. Custom inserts can help relieve pressure from painful areas.

 

Plantar calluses may benefit from periodic shaving.

 

SURGICAL MANAGEMENT

 

Surgical treatment is indicated for patients whose pain is unrelieved by nonoperative treatment or those with ulcerative lesions due to their deformity.

 

The goals of surgical treatment include the following:

 

 

 

Restoration of the weight-bearing function of the first ray Relocation of the plantar fat pad

 

 

Reduction of pressure under the lesser metatarsal heads Correction of claw toe or hammer toe deformities

 

A variety of methods have been described, but probably the most reliable method for accomplishing these goals is with fusion of the first MTP joint, resection of the lesser metatarsal heads, and either osteoclasis or open hammer toe repair.

 

 

 

FIG 3 • Loss of joint space, severe hallux valgus, and associated osteopenia. The straight arrow shows marginal

cortical erosion. The curved arrow shows the overlap between the proximal phalanx and the metatarsal head seen with dislocation of the joint.

 

 

 

 

 

FIG 4 • A. The patient is placed supine with the foot near the distal end of the table. B. The foot is positioned so the dorsal aspect can be visualized. This may require the use of a blanket roll or sandbag under the ipsilateral hip.

 

Preoperative Planning

 

These patients have a relatively poor soft tissue envelope, and this may compromise wound healing.

 

There is no perioperative standard as to whether to continue the use of disease-modifying antirheumatic drugs.

 

Consideration should be given regarding the need for cervical spine evaluation before general anesthesia.

 

Positioning

 

The patient is placed supine on the operating table, with the foot positioned near the distal end of the table (FIG 4).

 

Approach

 

The first MTP joint can be exposed through a dorsal or medial approach. Both provide adequate exposure, but the medial approach may provide a greater skin bridge between incisions. Incisions from previous procedures may dictate the approach used.

 

Lesser metatarsal head resection can be performed through dorsal longitudinal incisions or a plantar incision. Although the plantar approach may provide more direct access to the metatarsal head when the MTP joint has been dislocated for a while, there is more of a risk of problems with wound healing.

 

 

42

TECHNIQUES

• Hammer Toe Correction

Closed Correction

 

 

If the deformity at the PIP joint of the lesser toes are not severe, the contractures at the joint can be corrected by closed manipulation (TECH FIG 1).

 

Grasp the toe distal and proximal to the PIP joint and hyperextend it until the joint is resting in a neutral position.

Open Correction

 

If the deformity is severe, an open hammer toe correction is performed (TECH FIG 2).

 

Make an elliptical incision along the PIP joint.

 

 

Remove an elliptical portion of skin over the PIP joint and open the capsule over the joint. Release the collateral ligaments and expose the head of the proximal phalanx.

 

Resect the proximal phalanx at the metaphyseal-diaphyseal junction.

 

Stabilize the area with a Kirschner wire after performing metatarsal head resections.

 

 

 

TECH FIG 1 • Performance of osteoclasis, in which the PIP joint is passively manipulated to break up contracture.

 

 

 

TECH FIG 2 • An open hammer toe repair is performed with an elliptical incision over the PIP joint (A), followed by capsular release (B), exposure (C), and resection (D) of the head of the proximal phalanx.

• Lesser Metatarsal Head Resection

   

  Make longitudinal incisions over the second and fourth intermetatarsal spaces (TECH FIG 3A).

   

  Blunt dissection is recommended to minimize trauma.

   

  Identify the extensor digitorum longus and retract it to one side (TECH FIG 3B).

   

   

  Release the dorsal capsule and collateral ligaments off the metatarsal head (TECH FIG 3C). Bring the metatarsal head into the dorsal aspect of the incision.

   

  A curved retractor can be useful in obtaining exposure of the metatarsal head (TECH FIG 3D).

   

   

  43

   

  Use a sagittal saw to resect the metatarsal head. The blade is oriented in an oblique fashion from dorsal-distal to plantarproximal (TECH FIG 3E,F).

   

  Remove the metatarsal head as one fragment if possible. Take care to avoid leaving any bone fragments (TECH FIG 3G).

   

  Make sure the plantar aspect of the metatarsal is smooth and does not have a sharp edge.

   

   

   

  TECH FIG 3 • A. Dorsal, longitudinal incisions are made in the second and fourth intermetatarsal spaces.

  B. The extensor tendon is identified and retracted to one side. C. The dorsal capsule and collateral ligaments are released off the metatarsal head. D. A curved retractor can be helpful in exposure of the metatarsal head. E. The metatarsal head is brought into the dorsal aspect of the incision. F. Metatarsal head resection is oriented in an oblique fashion from dorsal-distal to plantar-proximal. G. The metatarsal head is removed as one fragment if possible. (continued)

   

   

  The metatarsal head resection usually starts on the second metatarsal and moves laterally (TECH FIG 3H).

   

  Leave the third metatarsal slightly shorter than the second and the fourth shorter than the third metatarsal. This creates a smooth cascade from medial to lateral.

   

  Pass 0.625-mm Kirschner wires from the base of the proximal phalanx to the tip of the toes (TECH FIG 3I).

   

  Pass the wires retrograde down the metatarsal shaft (TECH FIG 3J).

   

   

  44

   

   

   

  TECH FIG 3 • (continued) H. Progressive resection from the second to fifth metatarsal is performed, creating a smooth cascade. I. Kirschner wires are passed from the base of the proximal phalanx to the tip of the toes. J. The wires are then passed retrograde down the metatarsal shaft.

• Hallux Metatarsophalangeal Arthrodesis

 

Make a medial incision along the MTP joint (TECH FIG 4A).

 

Incise the capsule and expose the metatarsal head and proximal phalanx (TECH FIG 4B).

 

Prepare the joint surfaces by removing the remaining articular cartilage and exposing the underlying bone.

 

This can be done with the use of a cup and cone reamer system (TECH FIG 4C) or with rongeurs and curettes.

 

Flat cuts using a saw can also be used (TECH FIG 4D), but it is slightly more difficult to orient the cuts such that the correct alignment of the joint is obtained.

 

 

 

TECH FIG 4 • A. Medial incision for exposure of hallux MTP. B. The proximal phalanx and metatarsal head articular cartilage are exposed. (continued)

 

 

Place the MTP joint in 10 to 15 degrees of valgus and 20 to 25 degrees of dorsiflexion relative to the metatarsal shaft.

 

The correct dorsiflexion can be approximated by using a flat tray as a guide and keeping the pulp of the hallux 5 to 10 mm off the surface of the tray (TECH FIG 4E).

 

The position is held temporarily with a Kirschner wire (TECH FIG 4F).

 

Perform definitive fixation with cross screws or a dorsal plate or, in salvage cases, threaded pins (TECH FIG 4G-I).

 

Close the wounds and apply a forefoot dressing (TECH FIG 4J).

 

 

45

 

 

 

TECH FIG 4 • (continued) C. Joint preparation using a cup and cone reamer. D. Joint preparation with flat cuts. E. A flat tray is used to guide dorsiflexion. The pulp of the hallux sits 5 to 10 mm off the tray. F.

Temporary fixation with a Kirschner wire. G. Crossed screw fixation of fusion. H. Dorsal plate fixation. I.

Fixation with threaded pins. J. Postoperative forefoot dressing.

 

 

 

46

PEARLS AND PITFALLS

Hammer toe

correction

• Fixed deformities often require an open correction.

• Failure to correct the deformity can lead to recurrent deformity.

Metatarsal

head resection

• Oblique orientation of the resection helps decrease plantar pressure and sharp

  plantar edges.

• Loose fragments can lead to recurrent callus formation and should be avoided.

• Adequate decompression of the lesser MTP joint is seen with about 1 cm of space between the base of the phalanx and remaining metatarsal.

• Progressive shortening of the metatarsals from medial to lateral allows better stress transfer.

• After pin fixation, check the vascularity of the toe, as compromise occasionally requires pin removal.

Hallux MTP

fusion

• This is performed after the lesser metatarsal head resection to prevent an

  excessively long first ray.

• Excessive dorsiflexion can cause pain over the interphalangeal joint and under the metatarsal head.

• Fusion in greater than 20 degrees of valgus can increase the incidence of interphalangeal joint arthritis.

• Care must be taken to prevent excessive pronation or supination of the toe.

 

 

POSTOPERATIVE CARE

 

 

After placement of the forefoot dressing, a walking boot is applied (FIG 5). Patients are instructed to bear weight on the heel of the foot.

 

 

 

Sutures are removed 10 to 14 days after surgery. A forefoot dressing is used for the first 6 weeks. Kirschner wires are removed at 6 weeks.

A walking boot is used for 8 to 10 weeks, based on healing of the first MTP fusion.

OUTCOMES

Most studies have noted a significant improvement in ability to ambulate and in shoe wear options. Patient satisfaction rates are high and seem to hold up over time.

Patients should be aware that the lesser toes are unlikely to touch the floor and can be floppy, there may

be a change in shoe size, and toes may develop a rotational deformity.

 

 

 

 

 

COMPLICATIONS

Recurrent intractable plantar keratosis Recurrent toe deformities

Wound healing problems

 

FIG 5 • Postoperative walking boot.

 

Nonunion of MTP fusion Infection

 

SUGGESTED READINGS

1. Abdo RV, Iorio LJ. Rheumatoid arthritis of the foot and ankle. J Am Acad Orthop Surg 1994;2:326-332.

    

    

2. Beauchamp CG, Kirby T, Rudge SR, et al. Fusion of the first metatarsophalangeal joint in forefoot arthroplasty. Clin Orthop Relat Res 1984;(190):249-253.

    

    

3. Clayton ML, Leidholt JD, Clark W. Arthroplasty of rheumatoid metatarsophalangeal joints. An outcome study. Clin Orthop Relat Res 1997;(340):48-57.

    

    

4. Coughlin MJ. Rheumatoid forefoot reconstruction. A long-term follow-up study. J Bone Joint Surg Am 2000;82(3):322-341.

    

    

5. Garner RW, Mowat AG, Hazleman BL. Wound healing after operations of patients with rheumatoid arthritis. J Bone Joint Surg Br 1973; 55(1):134-144.

    

    

6. Hamalainen M, Raunio P. Long-term followup of rheumatoid forefoot surgery. Clin Orthop Relat Res 1997; (340):34-38.

    

    

7. Jaakkola JI, Mann RA. A review of rheumatoid arthritis affecting the foot and ankle. Foot Ankle Int 2004;25:866-874.

    

    

8. Lipscomb PR, Benson GM, Sones DA. Resection of proximal phalanges and metatarsal condyles for deformities of the forefoot due to rheumatoid arthritis. Clin Orthop Relat Res 1972;82:24-31.

    

    

9. Mann RA, Schakel ME II. Surgical correction of rheumatoid forefoot deformities. Foot Ankle Int 1995;16:1-6.

    

    

10. Mann RA, Thompson FM. Arthrodesis of the first metatarsophalangeal joint for hallux valgus in rheumatoid arthritis. J Bone Joint Surg Am 1984;66(5):687-692.

     

     

11. McGarvey SR, Johnson KA. Keller arthroplasty in combination with resection arthroplasty of the lesser metatarsophalangeal joints in rheumatoid arthritis. Foot Ankle 1988;9:75-80.

     

     

12. Nassar J, Cracchiolo A III. Complications in surgery of the foot and ankle in patients with rheumatoid arthritis. Clin Orthop Relat Res 2001;(391):140-152.

     

     

13. Spiegel TM, Spiegel JS. Rheumatoid arthritis in the foot and ankle— diagnosis, pathology, and treatment. The relationship between foot and ankle deformity and disease duration in 50 patients. Foot Ankle 1982;2:318-324.

     

     

14. Thomas S, Kinninmonth AW, Kumar S. Long-term results of the modified Hoffman procedure in the rheumatoid forefoot. J Bone Joint Surg Am 2005;87(4):748-775.

     

     

15. Thordarson DB, Aval S, Krieger L. Failure of hallux MP preservation surgery for rheumatoid arthritis. Foot Ankle Int 2002;23:486-490.

     

     

16. Trieb K. Management of the foot in rheumatoid arthritis. J Bone Joint Surg Br 2005;87(9):1171-1177.

     

     

17. Vandeputte G, Steenwerckx A, Mulier T, et al. Forefoot reconstruction in rheumatoid patients: Keller-Lelievre-Hoffman versus arthrodesis MTP1-Hoffman. Foot Ankle Int 1999;20:438-443.