Distal femoral flexion deformity from growth disturbance treated with a two-level osteotomy and internal lengthening nail

Abstract

Salter Harris fractures of the distal femur can lead to growth disturbance with resulting leg length inequality and knee deformity. We have looked at a case series (3) of patients who presented with a distal femur flexion malunion and shortening treated with a distal femoral osteotomy and plating and a proximal femoral osteotomy with a magnetic internal lengthening nail. Does a two-level osteotomy and internal fixation approach provide a reliable result both radiographically and functionally? The average knee extension loss was 12°, LLD 47 mm, PDFA 65°, MAD 2 mm. The patients were treated with an acute, posterior, opening wedge osteotomy of the distal femur stabilized with a lateral plate and screws and grafted with cancellous chips and putty. A second osteotomy was made proximally in the femur percutaneously, and the internal lengthening nail was inserted. Lengthening was done at approximately 1 mm/day. The average extension gain was 12°; amount of lengthening at the proximal site was 40 mm, LLD was 3 mm. The average PDFA was 81°, and MAD 3 mm. There were no complications. Functional results were excellent. Bone healing index was 24 days/cm. The average distance from the distal osteotomy to the joint line was 57 mm. The technique of two-level femur osteotomy stabilized with a plate and lengthening nail yielded excellent results with acceptable correction of deformity, full knee extension, and improved function. There were no complications including implant failure, infection, need for blood transfusion, knee stiffness, nonunion, compartment syndrome, or malunion.

Combined antegrade femur lengthening and distal deformity correction: a case series

“…We had similar outcomes in our cohort of congenital and acquired deformities, suggesting that this technique holds reliability in correcting limb length and distal femur deformities of different etiologies. Regarding the knee range of motion in children with flexion deformity, extension gained was between 12 and 30°in our patients, similar to the 15°reported by the aforementioned authors [18].…”

“…After the surgery and at a lengthening rate of 1 mm/day, the mean LLD was only 8 mm, with an average correction of 43 mm. This correction is in line with the usual lengthening achieved using the PRECICE nail, which has commonly reported lengthening averages between 35 and 44 mm [7][8][9]18]. Achieved MAD and LDFA correction in patients with valgus were 18.3 mm and 5.8°, respectively, in a prior study using an external fixator in conjunction with an ILN to achieve simultaneous femoral lengthening and deformity correction [14].…”

“…This advantage is highlighted in patients with congenital deformities who might benefit from early interventions. In addition, retrograde nailing can itself increase flexion deformity and varus and valgus angulation in patients, thereby exacerbating the additional deformities present [18]. In antegrade nailing, less restriction of the knee movement can be expected [24].…”

“…In light of the advantages of using a single procedure with an antegrade ILN and a DFO stabilized with a plate, we use this procedure to treat shortening and distal femur deformities. This technique was described by Fragomen and Fragomen who report their experience in treating three patients [18]. Satisfactory limb lengthening and distal deformity correction were achieved.…”

“…Most commonly, retrograde nailing with blocking screws is used for distal femur deformities [14,17]. To avoid complications associated with this technique, here, we report our experience with a less common approach in the correction of different distal femur angular deformities accompanying LLD: antegrade nailing and the use of a distal femoral osteotomy (DFO) stabilized with a plate [18].…”