19:21
Published February 19, 2016

Everything You Always Wanted to Know About Total Knee Replacement in Ankylosed Knee (But Were Afraid to Ask)

An ankylosed knee is defined as a knee with an arc of movement of less than 30°. The knee joint may be ankylosed in flexion because of contracture of the posterior soft-tissue structures after surgical procedures (ie, high tibial osteotomy) or because of juxta-articular adhesions. The knee joint may be ankylosed in extension because of extensor mechanism shortening (quadriceps contracture, patella baja), heterotopic ossification, or intra-articular adhesions. Performing total knee arthroplasty in a patient with an ankylosed knee may be one of the most difficult surgical challenges, even for expert joint surgeons. Studies have reported a 14% to 45% rate of complications and a mean expected postoperative range of movement from 60° to 75°. Understanding the etiology of an ankylosed knee is essential, and infection should be ruled out.

This video discusses the complex case presentation of a patient with hemophilia and an ankylosed knee and analyzes in a stepwise manner the main intraoperative problems we had to manage: difficult exposure and extensor mechanism shortening associated with patellofemoral fusion, definition of anatomic landmarks and the joint line, fine tuning in soft-tissues releases, and selection of implant constraint necessary to achieve a mobile but contemporary stable knee. In patients with longstanding stiffness or ankylosis, disuse osteoporosis frequently occurs, which may further jeopardize ligament attachment strength and increase the risk for ligament avulsion on attempted flexion. In addition, because of the potential for flexion-extension gap mismatch and preoperative and/or intraoperative ligamentous dysfunction, we recommend a full revision armamentarium, including more constrained systems, smaller implants, stem extensions, augments, sleeves, offset stems, and wedges, in the operating room. The expectations of the surgeon and the patient must be realistic and clearly defined preoperatively to improve results and patient satisfaction.