Background and aims: Psoriatic arthritis is commonly associated with bone pathology including entheseal new bone formation and osteolysis. On MRI, areas of active clinical involvement are represented by bone oedema and synovitis. The purpose of this study was to assess the impact of infliximab on bone oedema in PsA as shown by magnetic resonance imaging.
Methods: 18 patients with joint swelling, psoriasis and seronegativity for rheumatoid factor received 4 infusions of infliximab 3 mg/kg in combination with methotrexate. MRI of affected hand (12 patients) or knee joints (6 patients) was performed pre and post therapy. The primary outcome was the assessment of bone oedema and synovitis at 20 weeks as shown by MRI. Secondary outcomes included the ACR response criteria, psoriasis skin scores (PASI) and a quality of life measure (PsAQoL).
Results: At baseline, bone oedema was seen in 50% of the patients (7 hands and 2 knees) in 30% of scanned joints and this improved or resolved in all cases in the hand joints (p=0.018) and one knee joint at 20 weeks. MRI synovitis was reduced in 90% of cases. Likewise a statistically significant improvement in all clinical outcomes was seen at week 20 including PASI (p=0.003) and PsAQoL (p=0.006). 65% (n=11) of the patients achieved an ACR response, of which 45% had ACR70 or above and 54% ACR20 or ACR50.
Conclusions: Infliximab therapy is associated with dramatic improvements in MRI determined bone oedema in PsA in the short term. It remains to be determined whether this translates into the prevention of radiographic new bone formation, bone fusion or osteolysis in PsA.
- bone oedema
- magnetic resonance imaging
- psoriatic arthritis