Ultrasonographic measurement of the dimensions of proximal and distal patellar fragments after Niebauer-King Procedure for the management of congenital dislocation of the knee

Objective: The aim of this study was to ultrasonographically measure the dimensions of the proximal and distalpatellar fragments to determine whether postoperative growth differences existbetween the fragments in children with congenital dislocation of the kneetreated by Niebauer Kings quadricepsplasty. Methods: This retrospective study included six congenitaldislocated knees of four children with arthrogryposis multiplex congenita (AMC)(3 girls; mean age = 40 months; age range = 9-44 months), presented with severe hyperextension knee contractures,which were treated by Niebauer-King's quadricepsplasty.The transverse, craniocaudal, and anteroposterior dimensions of the patellaewere measured ultrasonographically 20 (range = 6-42) months postoperatively by a singleradiologist. Results: The mean transverse, craniocaudal, and anteroposteriordimensions of proximal and distal halves of the patellae were: 11.46 (7.0-16.9)-10.5 (8.0-14.4); 17.4 (14.0-21.0) -16.68 (14.5-19.3); 6.76 (5.6-7.9) -7.76 (7.0-9.4) mm respectively. There was no significantdifference in craniocaudal and transverse dimensions, but the anteroposteriordimension (thickness) of the distal patellae articulating the knee joint had agreater thickness (P = 0,01). Conclusion: Evidence from this study has shown that a bettergrowth can be expected in the distal fragment of the patella compared with theproximal fragment following treatment with Niebauer-King's quadricepsplasty in children with congenital dislocation ofthe knee.