Future directions in knee replacement

Abstract

The use of artificial joints for the treatment of osteoarthritis is expected to expand considerably over the next decade. While newer technologies can offer yet further improvements in total knee systems, implementation will be strongly affected by the need to satisfy apparently competing requirements. Patients expect quicker rehabilitation, improved performance, and lifelong durability; on the other hand, economic constraints require a reduction in cost for each procedure, as well as early intervention and preventative measures, while there is increased pressure from health care systems to use evidence-based medicine as the standard of choice for implants and techniques. The success of a knee replacement depends on the design itself, the surgical technique, the rehabilitation, and, not least, the patient. The major goal of the implant design can be redefined as a restoration of normal knee mechanics, whether by maximum preservation of tissues, or by guiding surfaces that replace their function. Surgical technique needs to be less invasive but achieve optimal patient-specific alignment and soft tissue balancing. Rehabilitation procedures must achieve the expectations of realistic patients. Testing and evaluation methods need to be upgraded for enhanced predictability. This paper discusses current trends and future possibilities to address this expansive scope of design criteria.

Analysis of in-vivo articular cartilage contact surface of the knee during a step-up motion

“…In knee arthroplasty surgeries, majority of the total knee replacement component designs have also adopted a femoral convex to tibia concave contact concept (De Valk et al, 2016; Nagerl et al, 2015; Walker and Sathasivam, 2000; Walker et al, 2010). Recently, medial pivoting knee motion has also been adopted in several knee replacement designs that are aimed to reproduce anatomic knee joint motion patterns (Chinzei et al, 2014; Ishida et al, 2012; Morra et al, 2008; Pritchett, 2011; Schmidt et al, 2003; Schmidt et al, 2014).…”

“…However, due to the challenge in measurement technologies, it is difficult to determine local cartilage surface shape at the articular contact locations during in-vivo physiological activities of the knee. This information is instrumental for development of surgical strategies to treat cartilage related pathologies that are aimed to repair tibiofemoral articular surfaces (such as using cartilage repair and partial or total knee arthroplasty) and to restore normal knee joint function (Henak et al, 2013; Nagerl et al, 2015; Walker and Sathasivam, 2000; Walker et al, 2010). …”

Measurement of joint kinematics using a conventional clinical single‐perspective flat‐panel radiography system

“…The purpose of this study was to evaluate the efficacy, accuracy, precision, and clinical safety of measuring 3D joint motion using a clinically available, FP radiography system prior to its application in vivo to study TKR and HTO patients. With over a million of these procedures performed per year worldwide, and a predicted annual growth of 10%, 40 the presented registration technique is applicable to a growing cohort of patients. Toward this goal an automated image-based tracking algorithm was implemented, with particular attention paid to addressing the problem of determining marker correspondence between the sparse model and marker projections within radiographic frames.…”

Porous squeeze-film flow

“…As well as being of fundamental scientific and medical interest in its own right, understanding the lubrication of the knee is of crucial importance in the development of total-knee-replacement technologies (see, for example, Walker et al (2010)). Figure 11 shows sketches of the main anatomical features of the human knee joint.…”