Bilateral Congenital Dislocation of the Knee

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A female infant was delivered at 39 weeks of gestation via cesarean delivery because of nonreassuring fetal status. Prenatal sonography performed 1 week before delivery revealed oligohydramnios. Postdelivery, both knees were hyperextended, with no other anomalies (Figure 1). Radiography of both knees showed posterior dislocation of the femur on the tibia (Figure 2); thus, bilateral congenital dislocation of the knee was diagnosed.Figure 2Radiograph showing posterior dislocation of the femurs on the tibias.View Large Image Figure ViewerDownload Hi-res image Download (PPT) Both knees could be flexed by manipulation. We performed serial casting for both knees in the functional position (Figure 3) for 1 month, after which bilateral congenital dislocation of the knee appeared to have resolved. Congenital dislocation of the knee is a congenital malformation characterized by hyperextension of the knee. The deformity can be unilateral or bilateral, with an estimated incidence of 1 in 100 000 deliveries and has a female predominance.1Mehrafshen M. Wicart P. Ramanoudjame M. Seringe R. Glorion C. Congenital dislocation of the knee at birth, part I: clinical signs and classification.Orthop Traumatol Surg Res. 2016; 102: 631-633Abstract Full Text Full Text PDF PubMed Scopus (24) Google Scholar The etiology of congenital dislocation of the knee might involve extrinsic factors, including fetal molding due to oligohydramnios or breech position, abnormalities of the anterior cruciate ligament, and quadriceps contracture, or, rarely, intrinsic factors, such as Larsen syndrome, arthrogryposis, Ehlers–Danlos syndrome, and achondroplasia.2Abdelaziz T.H. Samir S. Congenital dislocation of the knee: a protocol for management based on degree of knee flexion.J Child Orthop. 2011; 5: 143-149Crossref PubMed Scopus (33) Google Scholar Successful management depends on the severity of the congenital knee dislocation and includes physiotherapy, serial casting, and/or surgery. Typically, the prognosis is favorable; however, it can be severe in complicated cases. Poor prognostic factors include irreducible dislocation, coexisting general syndromes, and absence of the anterior skin groove.3Rampal V. Mehrafshan M. Ramanoudjame M. Seringe R. Glorion C. Wicart P. Congenital dislocation of the knee at birth, part 2: impact of a new classification on treatment strategies, results and prognostic factors.Orthop Traumatol Surg Res. 2016; 102: 635-638Abstract Full Text Full Text PDF PubMed Scopus (13) Google Scholar