Internal derangement of the knee in fibular hemimelia: Radiographic and MRI findings

BackgroundFibular hemimelia is a rare bone dysplasia with partial or complete absence of the fibula. There are many associated lower limb deformities.MethodsWe describe the commonly associated bone and soft tissue abnormalities in the knee joint in a case series of six knees in five patients with fibular hemimelia who underwent both radiographic and MR imaging.ResultsIn all knees, there was an elongated conjoint tendon of the lateral collateral ligament and biceps femoris. In five out of six knees, there was trochlear dysplasia. In four out of six, there was complete absence of the anterior cruciate ligament. In four out of six, there was an abnormal lateral meniscus (three were hypoplastic and one absent).ConclusionThese associations in fibular hemimelia, although unpredictable, have relevance in the guidance of further orthopaedic management in this complex condition.