Hip arthritis in the TNF-Blockade era: an unresolved issue?

Background

Hip involvement is a major cause of morbidity in patients with JIA. TNF-antagonists have improved the control of JIA.

Methods

We report on the evolution of hip arthritis in a series of 15 JIA (7 m/8 f; 9 sJIA, 4 pJIA, 2 oeJIA) patients treated with TNF-antagonists add-on MTX. Clinical disease activity, medication, hip x ray and MRI images were recorded.

Results

Median disease duration at start of TNF blockade was 51 months (14 – 108). Follow-up under TNF-blockade was 42 months (11–107).

Ten patients had hip involvement at start. Eight (7 sJIA, 1 eoJIA) showed progressive hip disease (PHD) during TNF blockade.

In patients with PHD active joint count decreased from 10 to 2.5. Systemic inflammation decreased (ESR 48.5 to 22.5). Steroid dose decreased from 0.315 mg/kg/d at start to 0.155 mg/kg/d. In 4, steroid tapering was impossible necessitating alternative therapy.

Hip imaging in 8 PHD children showed cartilage destruction, erosions and sclerosis (7) osteonecrosis of the femoral head (6), AVN (1), extensive osteophyte formation (1).

Discussion

In this cohort of 15 patients treated with TNF blockade, 8 patients had progressive hip disease despite better control of articular and systemic inflammation in the majority of them. Our findings suggest that the risk of progressive hip disease and damage may not be sufficiently abrogated by TNF blockade. Hip disease may progress despite a good general response and requires special vigilance especially in patients who do not show an optimal response to TNF antagonism.