Foot and ankle structured oral questions3: The rheumatoid foot

EXAMINER: Please have a look at this radiographic print and tell me what you see. (Figure 4.3.)

CANDIDATE: This is an AP radiograph of a forefoot. There is hallux valgus with displacement of the second toe and destructive change of all the metatarsophalangeal joints. I cannot say whether this is a weightbearing film or not as it is not labelled. The intermetatarsal angle appears increased and I would normally measure this on a weightbearing film. There may be deformities of the lesser toes and I would like to see a lateral view to clarify this.

EXAMINER: Good. A lateral view would be very helpful. What do you think is the underlying diagnosis?

CANDIDATE: The destructive changes suggest that this is an inflammatory polyarthropathy such as rheumatoid arthritis.

EXAMINER: Could it be anything else?

CANDIDATE: The appearances could be secondary to a neuropathic process.

EXAMINER. What might be the commonest neuropathic process that could cause these appearances?

CANDIDATE: A peripheral neuropathy such as that associated with diabetes mellitus would be commonest.

EXAMINER: How would you confirm your diagnosis?

Figure 4.3

Anteroposterior (AP) radiograph of rheumatoid forefoot.

CANDIDATE: A detailed history would be most informative. Specifically, I would enquire about pain, swelling, sensory alteration and medical history.

EXAMINER: OK. This lady gives a clear history of progressive, painful, bilateral small joint swelling and post-immobility stiffness. She has great difficulty finding comfortable shoes and describes walking as if on pebbles. She is not aware of any diabetes or sensory loss. What are your thoughts at this stage?

CANDIDATE: This appears to be an inflammatory arthropathy.

EXAMINER: Yes. Her feet are making her life pretty miserable and she would like you, as an orthopaedic surgeon, to do something to make them better. Your examination finds marked active synovitis and plantar tenderness under the metatarsal heads as well as a minimally correctable hallux valgus. There is some hammering of the lesser toes with a cock-up deformity of the second toe. Sensation and perfusion appear good. What are you going to do?

CANDIDATE: First, I would want to know if she is known to a rheumatology service and has had any attempt at nonoperative intervention.

EXAMINER: She has never seen a rheumatologist and has never sought help for her feet other than from you via her GP.

CANDIDATE: I would advise her that operations may be very helpful but that she should be formally assessed by a rheumatologist for diagnosis and disease control first. I would also advise review by the local podiatry and/or orthotics service as simple footwear modification may be all that is necessary to control her symptoms.

EXAMINER: I think that is appropriate advice at this stage. However, she returns to you a year later. Her synovitis is controlled by biologic agents but she has not found insoles and modified shoes helpful. How would you manage her at this point?

CANDIDATE: I would offer her a forefoot reconstruction consisting of excision of the lesser metatarsal heads, correction of lesser toe deformities and excision or fusion of the first metatarsophalangeal joint.

EXAMINER: Why?

CANDIDATE: This is a proven intervention with good results.

EXAMINER: How good?

CANDIDATE: More than 80% of patients report significant improvement.

EXAMINER: Would you fuse or excise the first metatarsophalangeal joint?

CANDIDATE: I would be guided by the age and functional demand of the patient in combination with the quality of the soft-tissue envelope. I would prefer to arthrodese the joint as I believe this aids maintenance of gait but, in a low-demand patient, excision is associated with reduced complications and more rapid rehabilitation.¹

EXAMINER: If we say this lady is 45 years old, what would you do?

CANDIDATE: I would plan arthrodesis.

EXAMINER: How would you secure the arthrodesis?

CANDIDATE: I would use an oblique compression screw augmented by a dorsal locking plate, as biomechanical and clinical studies have shown this to be the most reliable method.

EXAMINER : Would you excise the lesser metatarsal heads in a patient of this age who now appears to have their disease under control?

CANDIDATE: If the joint surfaces were well preserved but with subluxation of the joints it might be appropriate to perform shortening metatarsal osteotomies such as Weil's osteotomies to preserve the metatarsal heads and allow reduction of the joints with soft tissue releases.

EXAMINER: Surely that just prolongs the procedure and increases the risk of complication?

CANDIDATE: Yes, but it is very difficult to salvage a rheumatoid foot without metatarsal heads if the disease progresses in subsequent years and this patient is young.

EXAMINER: Tell me about the principles of surgery in rheumatoid arthritis.

CANDIDATE: Surgery is indicated when symptoms or deformity are uncontrolled or unbraceable. The overall objective is to produce a stable, plantigrade foot. Aim for a single operation with a high rate of success. Arthrodesis is the predominant procedure. There is a high risk of complication due to osteopenia, dysvascularity, soft tissue fragility and immunosuppression.

EXAMINER: I agree. What steps can a surgeon take to minimize the risk of complication?

CANDIDATE: Biologic agents should be stopped in the run up to surgery and not resumed until there is good evidence of postoperative healing. It should go without saying that meticulous handling of soft tissues is necessary.

Incisions must be planned with care, both to maintain skin bridges and to ensure closure if significant deformities are being corrected.

EXAMINER: How long would you stop biological agents for?

CANDIDATE: Two weeks preoperatively and two weeks

postoperatively.^2,3

EXAMINER: What about other disease-modifying anti-rheumatic drugs? Which other ones would you stop?

CANDIDATE: Studies have shown that there is generally no need to stop other drugs such as methotrexate or leflunomide.

EXAMINER: I would like to backtrack a bit. Would you alter your management if she also had signs and symptoms of hindfoot arthritis?

CANDIDATE: Generally, I would plan to address the most symptomatic area first. However, a less symptomatic fixed hindfoot deformity should be corrected before proceeding to the forefoot. Flexible hindfoot deformity could be left until more symptomatic.

EXAMINER: Which hindfoot joints are most commonly affected in rheumatoid arthritis?

CANDIDATE: The talonavicular joint is most commonly affected, followed by the subtalar and calcaneocuboid joints.

EXAMINER: Can you outline the arguments for and against isolated talonavicular fusion in RA?

CANDIDATE: Isolated talonavicular fusion is a lesser procedure than triple fusion for both patient and surgeon and effectively eliminates hindfoot motion. Historically, a non-union rate of up to 37% has been reported although more recent studies suggest the non-union rate using contemporary fixation is much less. A triple arthrodesis is more reliable and allows greater deformity correction.

EXAMINER: Thank you.

1. Rosenbaum D, Timta B, Schmiegel A et al. First ray resection arthroplasty versus arthrodesis in the treatment of the rheumatoid foot. Foot Ankle Int 2011;32 (6):589–594.

2. Lee MA, Mason LW, Dodds AL. The perioperative use of disease-modifying and biologic therapies in patients with rheumatoid arthritis undergoing elective orthopedic surgery. Orthopedics 2010;33(4):257–262.

3. Howe CR, Gardner GC, Kadel NJ. Perioperative medication management for the patient with rheumatoid arthritis. J Am Acad Orthop Surg 2006;14:544–551.