Comparison of clinical outcome after treatment of hip arthritis caused by MRSA with that caused by non-MRSA in infants.

We compared the results of four patients treated for septic arthritis of the hip caused by methicillin-resistant Staphylococcus aureus (MRSA) with those of five non-MRSA cases. All four patients with MRSA were neonates when infection occurred, and all four had preceding sepsis and marked swelling of the thigh. The mean duration of follow-up was 5.6 years. At the time of most recent follow-up, all four exhibited severe discrepancy in leg length, and their femoral heads exhibited high-grade deformation according to the Choi classification. In contrast, in the non-MRSA cases, the mean age at infection was 2.2 years and the mean duration of follow-up was 2.9 years. At the most recent follow-up, they exhibited no remarkable discrepancy in leg length and only low-grade deformation of the femoral head. In this study, patients with MRSA showed more marked deformity of the hip and discrepancy of leg length because of lower age and to the presence of organisms resistant to antibiotics. Possible strategies for early diagnosis to prevent poor results after MRSA-induced hip arthritis include the following: (i) ensuring that pediatricians are familiar with the early signs of infection of the hip joint, (ii) aggressive puncture and drainage of pus from the affected joint, and (iii) initial use of antibiotics effective in treating MRSA, especially for patients suspected to have MRSA in the neonatal nursery.