Tension band plate-guided growth of knee-flexion deformity in arthrogryposis multiplex congenita in which metaphyseal funnelization induced screw encroachment upon the neurovascular bundle.

Knee-flexion deformity in arthrogryposis multiplex congenita is treated by serial casting into extension, distal femoral osteotomies, distal femoral-guided growth, hemiepiphysiodesis, external fixation, capsulotomy, and soft-tissue releases. We are aware of four cases treated by distal anterior femoral-guided growth with tension band plates in which an unreported complication occurred: the screws of the tension band plates penetrated the posterior cortex of the femur during remodeling with metaphyseal funnelization risking the neurovascular bundle. Inclusion criteria were cases with arthrogryposis multiplex congenita and knee-flexion deformity, treatment at our institution by distal anterior femoral-guided growth with tension band plates, and radiographic evidence of posterior cortex screw penetration during remodeling from growth. Six knees (four cases) met the inclusion criteria. The average age at the distal anterior femoral-guided growth with tension band plate operation was 5.8 years. Radiographs after 6.6 years of follow-up showed that the screws of the tension band plates, which at surgery were intrametaphyseal, had penetrated the posterior cortex of the femur. Four knees (two cases) had diffuse pain around the knee to lower leg area, and instrumentation removal alleviated the symptoms. During distal anterior femoral-guided growth with tension band plate operation for knee-flexion deformity in arthrogryposis multiplex congenita, we found that the screws of the tension band plates, which were initially located inside the metaphysis, may protrude through the posterior bone cortex during metaphyseal funnelization with growth, and may encroach upon the neurovascular tissues. Level of evidence: Level IV - case series.