Abstract
Introduction Traumatic osteonecrosis of the femoral head in adolescents has a poor prognosis due to femoral head collapse and degenerative change. We hypothesised that early bisphosphonate treatment to reduce osteoclast activity could allow revascularisation and repair with maintenance of joint congruity.
Methods Nine patients with documented osteonecrosis are presented. There were six patients, who presented after unstable SCFE. Of these the index procedure had failed in three, requiring multiple early operations. The other three patients had sustained an inter-trochanteric fracture with a pelvic fracture, a traumatic hip dislocation and a femoral neck fracture respectively. They were treated with intermittent intravenous pamidronate (Aredia, Novartis) commencing within a mean one month of diagnosis (range 5 to 91 days). The dosing protocol has evolved over two years with the current dose being 9 mg/kg/year for 18 months. Mean follow-up is 19.8 months (range 13 to 30 months) with all patients followed for more than one year.
Results Eight of the patients are painfree. Six have been instructed to fully weight bear, while two can partial weight bear and one is non-weight bearing. Seven of nine patients do not show significant resorption of the femoral heads at the most recent follow-up. Of the two patients with significant resorption, one patient began to resorb after his medication was ceased, so it was recommenced. He has subsequently undergone a realignment procedure. The other patient had resorption of a section of the femoral head, which had not re-vascularised by 18 months, and this was elevated and bone grafted. These two hips were considered functional in the short term as they were pain free, but their deformity was expected to bring about early osteoarthritis in adult life.
Conclusions This early experience lays the foundation for prospective clinical trials of bisphosphonate therapy in adolescents with osteonecrosis. It appears that bisphosphonate treatment protocols for adolescents will need to be prolonged. Our current practice is for a duration of around 18 months with normalisation of uptake on bone scan as the end point for therapy.
In relation to the conduct of this study, one or more of the authors is in receipt of a research grant from a non-commercial source.
The abstracts were prepared by Mr Jerzy Sikorski. Correspondence should be addressed to him at the Australian Orthopaedic Association, Ground Floor, William Bland Centre, 229 Macquarie Street, Sydney NSW 2000, Australia.
