Sequelae of septic arthritis of the hip in children: a new classification and a review of 41 hips.

BACKGROUND

The sequelae of septic arthritis of the hip in children are diverse and represent a complex problem. A classification of the deformities is important to plan treatment and to give prognostic information. The radiographic main classification used provides detailed information of the deformities, but it is complicated and not feasible to apply in young children. The authors developed a simple and reliable method of classification and present the results of a large series of patients.

METHODS

The authors reviewed 37 children with 41 hips with sequelae of septic arthritis of the hip. Twenty-four were male subjects, and 13 were female subjects. Twenty-five had the acute infection at the neonatal period, and 16 were aged between 1 month and 3 years. None of them received adequate treatment at the acute process: 20 hips were not treated, and the other 21 had delayed drainage (at least 5 days after the onset of the infection). The hips were classified into 2 groups on the basis of radiographic appearance. Hips with sequelae grade 1 were reduced hips, with femoral head preserved (1A) or absent (1B); hips grade 2 were dislocated hips, with the femoral head preserved (2A) or absent (2B). There were 10 hips with grade 1A, 11 with grade 1B, 3 with grade 2A, and 17 were grade 2B. We compared our material and results with those presented by Choi et al and also compared the reliability of both classification. The criteria for satisfactory results were stability, range of motion of 50 degrees or more of flexion, a flexion contraction below 20 degrees, and a painless hip.

RESULTS

Our classification presented a greater concordance (25 of 41 hips against 7 in 41 for the Choi et al classification; P = 0.01). Thirty-seven hips were pain-free, and 4 had occasional pain. Thirty-seven hips had a satisfactory range of motion (90.2%). Stability was present in 29 hips (70.7%). Final results showed 24 hips classified as satisfactory and 17 as unsatisfactory. Our material and end results were comparable with those reported by Choi et al.Septic arthritis of the hip developed at the newborn period produced more severe sequelae. Hips with sequelae grade 1 have a good prognosis. Surgical procedures in these grades were necessary to correct acetabular dysplasia and improve congruency. Fifteen of 20 hips with sequelae grade 2 (unstable) underwent reconstruction. At a mean follow-up of 6.9 years (range, 2.7-11.3 years), satisfactory results were obtained in 8 of them.

CONCLUSIONS

The classification we proposed showed to be simpler and more reliable than the classification proposed by Choi et al. It may be useful to guide treatment and prognosis. Longer follow-up is needed to assess the real benefit of the reconstruction for unstable hips.