CASE DISCUSSION:  OLIGOARTICULAR JIA

JANUARY-FEBRUARY 2005

Case

A 2 year old female child is referred to your clinic by a local pediatric orthopedist.  She has had a swollen knee for 3 months.  She will not walk for 3 hours each morning and limps throughout the day.  She is getting worse despite liquid ibuprofen treatment at 200 mg. twice a day.  Your physical exam reveals a 3+ swollen right knee with a flexion contracture of -30° and has flexion to 85° only.  She will not walk for you in clinic.  The rest of her exam is normal, including her eyes.

Her laboratory workup 6 weeks before revealed a CBC with a WBC of 11,000 (45% segs, 6% bands), hemoglobin 11.1 g%, platelets 300,000, ESR 22 mm/hr (normal 0-20), CRP <0.2, and urinalysis and chemistry panel are normal.  Synovial fluid analysis showed a WBC of 12,000 cells/hpf (75% segs) with a synovial fluid glucose of 85 mg/dl and protein of 4.4 g%.  Gram stain, aerobic and anaerobic cultures, TB, and fungal cultures of the synovial fluid were negative.  An ANA titer was positive at 1:320 and the Lyme titer was negative.  Radiographs of the knee revealed only a synovial effusion.

Questions for discussion:

1)         What initial therapy would you choose?  Would it include an intra-articular steroid injection?

2)         Should this child be admitted for an inpatient rehabilitation stay?  If so, what criteria would you use for goals for discharge?

3)         What outpatient rehab-program would you suggest?

4)         Would you prescribe a night-time knee extension splint?

            How long should the child utilize the splint?

5)         If the child cannot tolerate NSAIDs, how would you proceed?

6)         Is there ever an indication here for prednisone or a remissive drug?

Case Discussion

          The child has ANA positive oligoarticular juvenile idiopathic arthritis and a severe knee flexion contracture. The management issues are:

            1. Controlling her active synovitis
            2. Addressing her flexion contracture and limited ambulation

            The first line treatment for a child with mild single joint disease is typically a non-steroidal anti-inflammatory drug (NSAID). This patient has been on ibuprofen for an undetermined period of time with inadequate dosing. For maximal NSAID effect, the ibuprofen should be dosed three times per day, or she could be switched to a twice per day medication such as naproxen at 10mg/kg per dose, or therapeutic doses of another Cox-1 inhibitor. If gastrointestinal side effects are a problem, she might benefit from the addition of a histamine-2 antagonist such as ranitidine, a proton pump inhibitor such as omeprazole, or carafate. Alternatively, one could switch her NSAID to a cox-2 inhibitor, but with refocoxib now off the market there is no liquid preparation available and a child of this age is unlikely to swallow a tablet easily.

            However, at this point she has developed a severe flexion contracture, as well as significant functional disability with refusal to walk for at least three hours per day. This degree of involvement is unlikely to respond to NSAIDS alone, and not as rapidly as she needs to allow aggressive intervention. More aggressive therapy is certainly warranted.

             The initial treatment approach to such a patient is intra-articular steroid injection, with the preferred agent being triamcinolone hexacetonide at a dose of approximately 1mg/kg. This will often result in rapid relief of the inflammation and associated pain. Performing this procedure under anesthesia will provide an opportunity to fully evaluate range of motion at the affected joint, as the exam may be less than optimal in the office setting in a child of this age who is awake and in pain. The physical therapist may wish to perform an exam at this time as well. Assessment for leg length discrepancy is also important. Finally, the patient should have had plain x-rays of her knee at some point in her evaluation. If these appeared normal or there was a question of erosions, one could consider performing an MRI of the knee during this same anesthesia to assess for erosions, as this would change her management.

             Occasionally, a single steroid injection is not effective at relieving joint inflammation. When this occurs, a second injection can be given a couple of weeks later. If, after a second intra-articular injection, swelling and pain persist, starting a steroid sparing agent such as methotrexate 0.5 mg/kg either orally or by subcutaneous injection weekly is the next step in medical management. Likewise, if erosions are seen either on plain films or MRI, beginning methotrexate is recommended in effort to prevent further erosions. If the patient is still non ambulatory or in significant discomfort when the methotrexate is begun, it would be appropriate to use oral prednisone at 0.2 mg/kg daily for several weeks until the methotrexate starts to take effect.

            While her inflammation is being addressed, this child also needs correction of her flexion contracture. Non ambulation in a child is an urgent situation, as she will rapidly lose muscle and bone mass, which will become more difficult to correct as time goes on. An inpatient rehabilitation admission is appropriate. Goals of this stay would include improved range of motion and ability to ambulate independently prior to discharge. Initial active therapies would include aggressive ROM and strengthening, with special attention to the medial quadriceps muscles, which work in the terminal extension range.

            Strengthening this muscle group is important both to regain ambulation and to oppose the tight hamstrings. The therapist should ensure that the patella is mobile and tracking properly to allow effective quadriceps action. Medial quadriceps strengthening can be achieved with activities such as “balloon soccer” and use of a wheeled toy that the child can sit on and push backward by extending her leg. Riding a tricycle also encourages extension of the knee, but at age 2 years this patient may not yet be developmentally ready. If the child has trouble activating the terminal extensors, one could use functional electrical stimulation or biofeedback to assist with muscle retraining.

             Stretching, particularly of the hamstrings which tend to shorten with knee contractures, is another important aspect of therapy. This would include manual stretching with the use of topical heat or ultrasound (controversial) to help loosen tissues and allow for greater stretch. A night time knee extension splint, as well as a day time drop out splint will help maintain newly gained extension. The dropout splint is used with the patient in the prone position with light weights about the ankle for thirty to sixty minutes twice per day. Children often object to splints and attempt to remove them. Encouraging the patient to decorate her splint (as many children do with casts) can help with acceptance, and use of D-rings or buckles rather than Velcro fasteners makes splints more difficult for children to remove during the night.

            Instructions for around the clock avoidance of knee flexion (e.g. a maximum of three hours per day of “sitting” time, and encouraging "tummy time" while coloring, playing games, or watching television) will also be helpful in gently extending the knee. Realistically, one can expect gains in extension from a long standing contracture of 10 -15 degrees per week. A danger of too rapid stretching is posterior subluxation of the tibia by a tight anterior cruciate ligament as knee extension is regained.

            If no improvement in range of motion is seen within one week of the above therapies, serial casting is indicated, with replacement of the cast every 36 to 48 hours to prevent loss of flexion. A desubluxation brace, which controls the posterior tibia and can be gradually adjusted to increase extension, may be an alternative to this.

            Leg length discrepancy, if present, also must be addressed both to aid in correction of the knee flexion contracture and to allow normal mechanics for ambulation. A lift for the contralateral shoe is effective. Finally, if when examined under anesthesia, and the aggressive physical therapy outlined above does not remedy the contracture, surgical referral for soft tissue release may be necessary, although the postoperative rehabilitation from this procedure is often difficult. Once the patient is ambulatory and the flexion contracture is improving, she can be discharged home, but with continuation of physical therapy on an outpatient basis three times per week, in addition to daily exercises and nightly use of the knee extension splint at home until ROM is normal.

Jennifer K. Turner, MD

Helen M. Emery, MD

Seattle Childrens Hospital

University of Washington

Seattle, WA

References

1.  Cleary AG, Murphy HD, Davidson JE. Intra-articular corticosteroid injections in juvenile idiopathic arthritis. Archives of Disease in Childhood. 2003;88:192-196.

2.  Emery HM, Bowyer SL, Sisung CE. Rehabilitation of the child with a rheumatic disease. Pediatric Clinics of North America. 1995; 42(5):1263-1283.

3.  Fredriksen B, Mengshoel AM. The effect of static traction and orthoses in the treatment of knee contractures in preschool children with juvenile chronic arthritis: a single subject design. Arthritis Care and Research. 2000;13(6):352-359.