Abstract
Introduction
Metal-on-metal hip resurfacing (MOMHR) is a good surgical indication for young active patients. However, it cannot be used in patients with an excessively short femoral head/neck. To address these cases, a new surgical technique has been developed comprising femoral head augmentation using impacted morcellized bone grafts.
Methods
32 osteoarthritis patients who had severe congenital insufficiency of the femoral head/neck were treated with MOMHR combined with femoral head augmentation. Mean patient age was 49 ± 9 years (18–66). The required amount of augmentation was calculated on preoperative X-rays and confirmed during surgery. Using specially designed instrumentation, bone chips produced while reaming the socket and trimming the head were impacted onto the head to achieve the desired reconstruction and lengthening. Finally, the femoral component was cemented.
Results
Mean head lengthening was 12 ± 2mm. Mean follow-up was 4.2 years (3–6). Mean preoperative Harris hip score was 58, increasing to 95 at follow-up (p<0.05). Mean leg lengthening was 2.2cm (p=0.001). In all Gruen zones, bone mineral density (BMD) decreased during the first 3 months. At 2 years, in zone 1, mean BMD increased to 96.8% (p=0.009) and to 102.1% in zone 7 (p=0.05). A correlation was found between valgus positioning of the femoral components and increased BMD (p=0.005). To date, only 1 patient has been revised due to socket loosening.
Discussion and conclusions
This bone grafting technique expands the use of MOMHR to patients with severe deficiencies of the femoral head, thereby leading to a more anatomical reconstruction with a full recovery of function and BMD of the proximal femur.
