Irreducible posterolateral dislocation of the knee: a case report

Irreducible posterolateral dislocations of the knee are rare lesions, generally caused by high-energy trauma inducing rotational stress and a posterior and lateral displacement of the tibia. In these conditions, the interposition of abundant soft tissue inside the enlarged medial joint space prevents spontaneous reduction or non-surgical treatment by manipulation of the dislocation. Surgical treatment is therefore compulsory. We report the clinical case of a woman who suffered a subluxation of the knee while jogging. The case we describe is of interest because it shows that even less severe knee dislocations, like this subluxation caused by a low-velocity sports trauma, may present in an irreducible form requiring open surgery. Clinical-instrumental monitoring did not reveal any signs of vascular or nerve injury. Owing to the irreducibility of the lesion we were obliged to perform open surgery in order to free the joint from the interposed muscle tissue and repair medial capsule-ligament lesions. Repair of the damaged cruciate ligaments was deferred to a second stage, but ultimately rendered necessary by the persistence of joint instability and the need to address the patient's functional needs. In the literature, different one- and two-step surgical options, performed by arthroscopy or arthrotomy, are reported for such related problems. The Authors discuss these various options and examine and discuss their own decision taken during the surgical work-up of this case.