Results of hip arthrodesis in adolescents by using the cobra-head plate for internal fixation

A retrospective study was conducted to examine the efficacy and potential m orbidity of hip fusion using the Cobra-head plate in adolescents. A heterog eneous group of 11 adolescents, with recalcitrant hip pain and an average a ge of 14.6 years, underwent unilateral hip arthrodesis with the Cobrahead p late for internal fixation. Seven (64%) patients achieved an uneventful cli nical and radiographic arthrodesis after a mean postoperative interval of 7 .4 months. Four index operations (36%) were complicated by pseudarthrosis. All patients who developed a postoperative pseudarthrosis ranked at or abov e the 90th percentile for their age-determined weight. The relationship bet ween the percentile-weight-for-age and the incidence of pseudarthrosis was statistically significant (p less than or equal to 0.001). Hip-arthrodesis procedures with the Cobra-head plate in adolescents at or above the 90th pe rcentile weight-for-age are associated with an unacceptably high rate of ps eudarthrosis. In this subset of patients, alternate or supplementary stabil ization methods should be considered.