High complication rates and technical difficulties of intramedullary fixation in children with osteogenesis imperfecta have prompted the modification of existing rod systems. The Sheffield telescoping intramedullary rod system was introduced to reduce the complications. It has a T-piece which is permanently fixed to prevent its separation and is expanded to reduce the migration. This study analyses the outcome of this rod system over a 12-year period in two specialist centres. Sixty rods were inserted in the lower limbs of 19 children with osteogenesis imperfecta. All children had multiple fractures of the bones before rod insertion. 39 rods were inserted into the femur, of which 3 were exchange and 4 revision procedures. 21 rods were inserted in the tibia. Eight children had intramedullary rodding of all the four lower limb long bones. The outcome was measured in terms of mobility status, incidence of refractures and rod-related complications. Our series demonstrates that there is significant reduction in refractures and improvement in the mobility status in children with osteogenesis imperfecta following intramedullary fixation. The frequent complication of T-piece separation and the need for reoperation has been overcome with the Sheffield modification of rod design. But the extracortical and metaphyseal migration of the rod continues to be a problem and further improvement in the design is desirable.
70 patients who underwent dynamic MRI scanning for chronic anterior knee pain were retrospectively evaluated. All patients had been symptomatic for over a year. 43 patients had been treated conservatively and 27 had undergone surgical procedures (arthroscopy -13, lateral release- 9, tibial tubercle transfer 5). The extent of subluxation, tilt and cartilage abnormalities on MRI scans, during resisted extension were assessed. Functional scoring (Oxford, Lysholm and Tegner scores) was done through questionnaires and correlated with the radiological findings. 54 (77%) patients were found to have some patellofemoral abnormality on the scans. Subluxation was the most common finding with mild subluxation in 30, moderate in 18 and severe in 17 knees. Mild tilt was seen in 26 knees and moderate to severe tilt in 14 knees. Tilt was found in association with subluxation except in 8 cases. Grade 1 and 2 cartilage wear were seen in 13 knees and Grade 3 and 4 in 21 knees. The “Tibial Tubercle to Trochlear Groove distance” (TTD) was measured in all knees and correlated with subluxation. The average distance was 13.5mm, 13.6mm and 18.8mm for mild, moderate and severe subluxation respectively. All patients with a TTD _ 20mm had moderate or severe subluxation. The specificity of a TTD _ 20mm for severe maltracking was 100% but the sensitivity was only 42%. The TTD appears to be the single most significant parameter determining patella tracking. We have proposed an algorithm for the surgical and non-surgical treatment of chronic anterior knee pain. We recommend lateral release for those with moderate and severe subluxation and a tibial tubercle transfer as well in those with a TTD _ 20mm. The functional scores did not zshow a significant correlation with the grading of subluxation.
On the imaging films, four measurements were made. They were patella subluxation, tilt, cartilage thickness and the Tibial Tubercle Trochlear distance (TTD). Patellar subluxation was classified as mild, moderate and severe. We found that a Tibial Tubercle Trochlea distance of 18mm had a specifity of 100% and a sensitivity of 89% for severe maltracking.
On the imaging films, four measurements were made. They were patella subluxation, tilt, cartilage thickness and the Tibial Tubercle Trochlear distance (TTD). Patellar subluxation was classified as mild, moderate and severe. We found that a Tibial Tubercle Trochlea distance of 18mm had a specifity of 100% and a sensitivity of 89% for severe maltracking.
High complication rates and technical difficulties of intramedullary fixation in children with osteogenesis imperfecta has prompted the modification of existing rod systems. The Sheffield telescoping intramedullary road has T-piece which is permanently fixed and is expanded to reduce metaphyseal migration. This study analyses the outcome of this rod system over an 11 year period in two tertiary referral hospitals. 60 rods were inserted in the lower limbs of 19 children with osteogenesis imperfecta. All children had multiple fractures of the bones before rod insertion. 39 rods were inserted into femur, of which 3 were exchange and 4 revision procedures. 21 rods were inserted into tibia. Eight children had intramedullary rodding of both femur and tibia bilaterally. The outcome was measured in terms of incidence of refractures, mobility status, functional improvement and rod related complications. Our series demonstrates that there is significant reduction in refractures and improvement in the functional status of children with osteogenesis imperfecta following intramedullary fixation. The frequent complication of T-piece separation and the need for re-operation has been overcome with Sheffield modification of rod design. But the incidence of the rod, particularly at the proximal end of femur remains high and further improvement in the design is desirable.
High complication rates and technical difficulties of intra-medullary fixation in children with osteogenesis imperfecta has prompted the modification of existing rod systems. The Sheffield telescoping intramedullary rod has T-piece which is permanently fixed and is expanded to reduce metaphyseal migration. This study analyses the outcome of this rod system over an 11-year period. 32 rods were inserted in the lower limbs of 11 children with osteogenesis imperfecta. All children had multiple fractures of the bones before rod insertion.24 rods were inserted into femur, of which 3 were exchange procedures for complications. 8 rods were inserted into tibia. 4 children had intramedullary rodding of all the 4 lower limb bones. The outcome was measured in terms of mobility status, incidence of refractures and rod related complications. Complications encountered include 2-rod migrations, one instance each of broken rod, bent rod and valgus drift in the tibia.There was no instance of epiphyseal damage or growth arrest. Our series demonstrates that there is significant reduction in refractures and improvement in the mobility status in children with osteogenesis imperfecta following intramedullary fixation. The frequent complication of T-piece separation and the need for reoperation has been overcome with Sheffield modification of rod design. Though the incidence of rod related complications remain high, our study concludes that Sheffield rod system compares favourably with the existing intramedullary devices for osteogenesis imperfecta in the literature.
