Abstract
Acetabular loosening is often dangerous because the patient is pain free for several years. The subsequent bone loss may represent the greatest challenge in revision surgery. The extension of the bone loss may be small or wide, but it could also be associated with several defects. Usually, the most affected district is the dome, especially because the cup leans to migrate proximally. The object of this study is to evaluate the use of an iliac stem cup (Link®) associated with impacted bone grafts in acetabular loosening and congenital hip dysplasia (CDH).
The surgical technique requires a posterolateral approach, dedicated cannulated hardware tools to improve iliac stem positioning, intraoperative C-arm and bone grafts to enhance primary stability. We performed 21 implants in 18 cases of acetabular loosening (10 grade 2 and 8 grade 3 according to Paprosky) and three CDH: average age was 68 years old in 14 women and seven men. Mean follow-up was 21 months. We used bone grafts in 17 cases. In one case we cemented the McMinn cup because of poor initial stability with no complications at 18 months. We noted radiolucency lines < 2 mm in one case and bone resorption in two cases. Mean Harris Hip Score (HHS) was 60 preoperatively and 88 postoperatively. The complications were: malpositioning of the stem (1%), sacroiliac pain (4%), superficial infection (2%) and DVT (1%).
The primary cementless stability is achieved by the aid of an iliac palpator checked by fluoroscopy: the palpator works as a guide for the iliac stem to avoid malpositiong or wrong inclination. In addition, the dedicated cup trials could also function as an impactor for chips bone grafts in the so-called “impaction grafting technique”. In conclusion, we confirm that the McMinn cup, despite a demanding surgical technique, represents a valid alternative to acetabular revision surgery because of the good initial stability and the respect of loading lines and it also allows the use of pressurised bone chips. Furthermore, the hip centre is restored in acetabular loosening and CDH.
