Prenatal diagnosis and postnatal outcome of fetal congenital knee dislocation: systematic review of literature

Abstract

ObjectivesCongenital Knee Dislocation (CKD) or Genu Recurvatum is a rare condition affecting 1 over 100,000 newborns, characterized by anterior hyperextension of the knee joint, increased transverse skin folds over the anterior surface of the knee and prominence of femoral condyles into the popliteal fossa. Prenatal diagnosis is poorly described in the literature and challenging, especially when it appears isolated and not in the context of polymalformative or syndromic patterns. The purpose of this study is to provide a comprehensive review of the available literature on prenatal diagnosis and postnatal outcome of this rare condition, to summarize the current evidence on this topic.MethodsWe performed a systematic review of the literature searching for prenatal diagnosis of CKD in all major internet‐based medical databases. A predefined combination of specific key words was used, focusing on intrauterine manifestations, diagnostic methods, prenatal behavior, postnatal treatment and neonatal outcome as well as long‐term outcome on ambulation, motion and joint stability. Study quality was assessed by means of National Institute of Health tool for the quality assessment of Case Series Studies. A summary of results was carried out providing proportions and rates of diagnostic and prognostic features associated with this rare condition.ResultsTwenty cases were retrieved for analysis including nineteen collected from the systematic review and one unpublished case from our experience. Median gestational age at prenatal diagnosis was 22 weeks (range 14‐38 weeks), generally by US. Bilaterality was observed in 11/20 (55%), the condition was isolated in 7/20 cases (35%) and associated to other anomalies in 13/20 cases (65%). An association was observed with oligohydramnios (20%) and invasive procedures were performed in 11 cases (55 %). Genetic studies were normal in all isolated cases and few genetic syndromes were present in 10 of the 13 (77%) non‐isolated cases for which information was available (Larsen, Noonan, Grebe, Desbuquois and Escobar syndromes). There were 7 terminations of pregnancy, of which 6 with associated anomalies and one isolated, 11 livebirths, one intrauterine death and one neonatal death. All fetal or neonatal demises were in fetuses with associated anomalies or abnormal genetics. Postnatal treatment was essentially conservative with only two reports (18% of the 11 liveborn neonates) of surgical interventions, all in cases with associated anomalies. The postnatal follow up was in most of the cases up to the first year and the motor outlook appears normal.ConclusionsCKD is a rare fetal anomaly with a prenatal diagnosis achievable from the early second trimester for which favorable outcome can be predicted when no associated anomalies are present. Prenatal diagnosis should include detailed US assessment and amniocentesis for extensive genetic studies, particularly in non‐isolated cases. Postnatal early treatment achieves success in most cases without surgical intervention and leads to normal motor outlook.This article is protected by copyright. All rights reserved.

Congenital Dislocation of the Knee in the Delivery Room

“…Prenatal diagnosis of CDK is challenging, as it is often undetected by ultrasound. In a recent review of 20 cases of CDK detected by prenatal ultrasound, the median gestational age at diagnosis was 20 weeks (range, 14–38 weeks) [ 12 ]. A 3-dimensional (3-D) with a real-time 3-D (4-dimensional) ultrasonographic evaluation seems advantageous, as it offers a more dynamic interpretation of the limb position and mobility [ 13 ].…”

Congenital dislocation of the knee complicated with bilateral hip dislocation: a case report and literature review

“…Previous studies have indicated that isolated CDK is a rare anomaly, and most isolated cases exhibit a favorable prognosis, with excellent motor function of the lower limbs and ambulatory ability. Conversely, complex cases involving genetic syndromes or multiple anomalies generally have poor prognoses [ 18 – 20 ]. Moreover, there is a tendency for numerous malformations accompanied by developmental abnormalities affecting the upper extremities, face, digestive tract, and reproductive system.…”

“…Before birth, the diagnosis can be confirmed through prenatal 3D or 4D ultrasound, typically performed around the 20th week of gestation [ 3 ]. By employing prenatal diagnosis, swiftly referring to adept pediatric orthopedic surgeons, and initiating early conservative treatment, the necessity of surgery can be significantly reduced and the efficacy of the treatment enhanced [ 18 ]. Following birth, the diagnosis is typically confirmed based on observing distinctive deformities, a physical examination, and conventional knee X-rays [ 23 ].…”

“…CDK is a rare condition that typically exhibits a favorable prognosis in isolated cases but presents a generally poor prognosis when accompanied by multiple deformities [ 18 ]. However, a retrospective study involving 9 patients with at least 9 years of follow-up ,it was demonstrated that timely diagnosis and prompt initiation of suitable conservative treatment resulted in favorable long-term functional outcomes in the affected limbs, with few occurrences of complications and recurrence [ 26 ].…”

Bilateral congenital knee dislocation

“…Poor prognostic factors include an associated syndrome, knee flexion <50% and absence of an anterior skin groove 5. In cases of isolated congenital knee dislocation, the outlook for motor function of the lower limbs and ambulation is excellent 6…”