Abstract
Aim
Since 2008 we have been using third generation Fassier Duval (FD) telescopic rods for children with complex and severe osteogenesis imperfecta (sOI). We present our experience with the technique.
Method
8 children with sOI have undergone rodding of 16 lower limb long bones; 6 tibial, 10 femoral. 3 were revision procedures, exchanging previous Sheffield rods that had been implanted with the female portion only. Indications were recurrent fracture and/or progressive deformity. Age range and follow up are 2–12 and 0.4–4.75 years respectively. All but one of the procedures were performed by a single surgeon.
Results
There have been 3 re-fractures at 3–5 years with bending of the implant at the rod-tip interface and one re-fracture around a well-positioned implant without bending, all requiring revision. Some female femoral rods have migrated distally (3/10) leading in one case to re-fracture above the implant, which was also revised. All rods have initially telescoped well but we have experienced high pull out rates of the threads in the distal tibia (3/6) at an average 18 months post implantation (range 14–20 months). None has yet required revision for this. Proximal migration of the femoral female component has not occurred except in one revision case, which responded well to interference wire fixation. We have one case of coxa vara that developed in a child whose femur was rodded at 2 years of age.
Conclusion
The FD implants have functioned well and enabled us to avoid opening the ankle joint for tibial roddings. Nonetheless the re-fracture rates remain high in this group of severely affected children and are comparable to older generation implants. Proximal femoral and distal tibial anchoring points remain common sites of failure though rarely require early re-operation.
