Exposure options for revision total knee arthroplasty

Abstract

Awell-planned surgical approach is crucial to avoid damaging important structures in a knee already compromised by previous surgery. With previous knee surgery, the skin may have become densely scarred into the deep fascial layers or even to the underlying bone. This scarring may be the effect of multiple incisions, draining sinuses, or old skin sloughs. As a result, exposure in revision knee arthroplasty is particularly difficult secondary to a loss of tissue elasticity and the overall thickening of the capsular envelope that surrounds the knee. To achieve a safe and satisfactory exposure for revision surgery, the surgeon must give special consideration to any condition that has resulted in a restricted arc of knee motion (less than 90 degrees of flexion). A loss in the elasticity of the extensor mechanism, a common sequel to the development of arthritis, may be exacerbated with total knee arthroplasty failure. Patients lose flexibility secondary to guarding from the pain of arthritis, and they may lose additional motion in response to postsurgical pain following their index arthroplasty.With limited knee flexion, stretching of the knee structures such as the capsule and the soft tissue envelope does not occur. The elasticity of the soft tissue structures is lost. Pain associated with failure of the prosthesis often results in further loss of knee motion, as does the trauma of multiple revision operations. In addition, the biologic response to infection, particulate debris, and the soft tissue trauma associated with knee instability further compromise tissue compliance. Multiple exposure options exist for the stiff and badly scarred knee. Wide exposure through a full incision reduces surgical time and enhances component removal, soft tissue balancing, bone reconstruction with allografts or augments, and reimplantation of long-stemmed revision components. By properly selecting and implementing the exposure method, the surgeon can avoid the devastating complications of wound slough and/or iatrogenic knee instability. It is most important that the ligamentous support to both the tibiofemoral and patellofemoral articulations is not compromised. Instability of either the tibiofemoral or patellofemoral joint dooms the revision arthroplasty to failure. Patients at increased risk for wound healing complications include immunocompromised individuals, such as those with rheumatoid arthritis, systemic lupus erythematosus, and vasculitis, as well as patients on immunosuppressive drugs and corticosteroids. These patients are prone not only to wound healing problems, but because of the friable nature of their skin, they are also prone to skin sloughs from manual pressure or vigorous skin retraction. Often, the epidermal layer is thin with poor elasticity that makes skin closure difficult. Extra caution is warranted throughout the surgical procedure to protect the epithelial barrier from external insults. All patients are at increased risk of infection with revision total knee arthroplasty. The risk of deep infection in revision surgery often is reported as 3 to 4 times greater than with primary total knee surgery. The increased risk is a combination of the poorly vascularized tissue often encountered with multiple operations, the increased operative time for revision surgery, prior wound healing problems, and the increased age and poorer metabolic state of this patient population. The risk of infection is even greater in diabetic patients and those immunocompromised either by disease or medication. © 2005 Springer Science+Business Media, Inc. All rights reserved.