Bilateral Congenital Posterior Cruciate Ligament Hypoplasia: A Case Report.

Abstract

Congenital aplasia or hypoplasia of the cruciate ligaments is an infrequent condition. The absence of the posterior cruciate ligament (PCL) is extremely rare and is usually associated with other congenital abnormalities of the lower limb such as anterior cruciate ligament (ACL) agenesis, absence of one or both menisci, and absence or dysplasia of the patella1-7. To the best of our knowledge, only one case of a unilateral PCL absence8 and one case of bilateral PCL hypoplasia9 have been reported in the literature. We present the case of a professional athlete with bilateral congenital PCL hypoplasia without other associated congenital anomalies. The patient was informed that data concerning the case would be submitted for publication, and she provided consent. A twenty-nine-year-old female professional athlete, who had played handball from the age of twelve years and had competed in the premier league from the age of sixteen years, sustained a twisting injury to the right knee while landing. Seven days later, examination revealed a minimal right knee effusion and a positive Lachman test with a soft end point. The posterior drawer sign had a hard stop, and the posterior sag sign was negative. No lateral or medial instability was observed. Active and passive knee motion was intact. The patient denied any family history of skeletal congenital abnormalities; no abnormalities had been noted during pregnancy, childbirth, or childhood. Five years prior to this event, she had given birth to a healthy girl who had normal physical and mental development. Magnetic resonance imaging (MRI) of the right knee (Figs. 1-A, 1-B, and 1-C) demonstrated a recent ACL tear with a fully disorganized and partially retracted ligament as well as associated intra/periligamentous edema. The PCL did not have a normal appearance; there was only a thin, hypointense bandlike structure, …