Failure of a Knee Joint Load Absorber: Pain, Metallosis and Soft Tissue Damage.

Abstract

Osteoarthritis (OA) is a chronic, progressive disease resulting in loss of function and pain due to articular cartilage loss and represents the most common disease among musculoskeletal disorders [7, 8, 15]. Various strategies for the treatment for medial OA of the knee including conservative and operative treatment options are currently used. Surgical treatment includes, among others, high tibial osteotomy (HTO), unicompartmental knee arthroplasty (UKA), and total knee arthroplasty (TKA). Conservative treatment comprises a variety of different options including analgesic and/or anti-inflammatory medication, bracing, physiotherapy, and intra-articular injections of corticosteroids or viscosupplements. The general problem with conservative treatment is that despite amelioration of symptoms, the progressions of OA are usually unhalted [10]. London et al. [12] illustrated an additional problem: There are patients unwilling or unsuitable to undergo extensive surgery by means of arthroplasty or HTO. These patients are often young and show mild to moderate but symptomatic OA on radiographs that limits their inactivities of daily life, especially participation in recreational sports. These patients are reported to be within a “treatment gap” with no perfectly suitable treatment concept available [12]. A recently published survey illustrated that the majority of orthopedic surgeons are aware of this treatment gap and feel the need for a suitable treatment option for the young patient with symptomatic early osteoarthritis [11]. Recently, a new surgical implant was introduced for the treatment of medial knee osteoarthritis trying to address this treatment gap. The device consists of titanium alloy base plates rigidly attached to the medial aspect of tibia and femur connected to a cobalt/cobalt chrome alloy spring crossing the joint line. This is meant to reduce the load of the medial knee joint compartment while preserving the joint and not significantly affecting the lateral joint contact mechanics [6]. It was designed to reduce pain and stop progression of OA of the medial compartment [5]. Our purpose is to describe the clinical course of a 52-year-old patient implanted with this type of device. In this case, the device failed necessitating complete implant removal 18 months following implantation due to pain, metallosis, and penetration of the joint capsule.