PDF icon PDF herunterladen
J Knee Surg 2014; 27(03): 169-170
DOI: 10.1055/s-0034-1376335
Special Focus Section
Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

Advances in Total Knee Arthroplasty

Steven F. Harwin
1   Division of Adult Reconstruction and Total Joint Replacement, Department of Orthopaedic Surgery, Mount Sinai Beth Israel, New York, New York
,
Samik Banerjee
2   Center for Joint Preservation and Replacement, Rubin Institute for Advanced Orthopedics, Sinai Hospital of Baltimore, Baltimore, Maryland
,
Kimona Issa
3   Department of Orthopaedic Surgery, Seton Hall University School of Health and Medical Sciences, South Orange, New Jersey
,
Michael A. Mont
2   Center for Joint Preservation and Replacement, Rubin Institute for Advanced Orthopedics, Sinai Hospital of Baltimore, Baltimore, Maryland
› Institutsangaben
Weitere Informationen

Publikationsverlauf

Publikationsdatum:
09. Mai 2014 (online)

   Lizenzen und Reprints
Preview

The incidence of lower extremity total joint arthroplasty has increased tremendously during the past decade. In addition, there has been a change in the demographics of patients who undergo total knee arthroplasty (TKA). Nearly 41% of all TKAs (1.5 million procedures) in the United States were performed in patients who were 50 to 69 years of age.[1] With the current trends of cost reductions in the healthcare sector, there has been an increasing need for the development of newer cost-effective technologies in total joint arthroplasty with the ultimate potential goal of improving limb alignment, enhancing functional outcomes, providing more durable implant fixation, and superior overall implant survivorship. This initially led to the development of computer-assisted navigation, and more recently, in the use of patient-specific instrumentation in TKA. Moreover, the ensuing decade has also seen great progress in the technological front in TKA with the development of modern fabrication technologies such as additive layer manufacturing that are purportedly more commercially viable and have the potential to make a profound impact on the manufacturing of anatomically more conforming and complex implant geometries at faster rates and lower costs.[2] [3] [4] In this special supplement on the “Advances in Total Knee Arthroplasty” we will review some of these modern technologies.

Navigation in TKA was introduced with the goal of reducing limb alignment outliers in sagittal, coronal, and axial planes, which proponents believed would potentially enhance implant survivorship and improve patient reported functional outcomes.[5] Despite the initial success reported with computer-assisted surgery regarding radiographic alignment, there are many unanswered questions concerning limb alignment in TKA, such as the use of a more patient-specific approach based on the patient's own anatomic variations.[6] [7] Current concerns about high institutional costs, intraoperative difficulties, steep learning curves, registration errors, and tracker pin complications have reduced the initial enthusiasm regarding navigation use.[7] [8] Clayton and co-authors in their article have elaborately described some of these controversies and potential pitfalls with the use of intraoperative navigation, and in addition, have reviewed some of the recent clinical and radiographic outcomes of computer-assisted navigation surgery.

To avoid some technical problems and reduce costs, patient-specific cutting blocks were developed along with the advances in rapid prototyping technologies to potentially reduce intraoperative instrumentations, operating times, and minimize alignment outliers.[9] [10] [11] [12] Jauregui and co-authors in their article have reviewed the history and development, the clinical and radiographic outcomes, and the cost-effectiveness of patient-specific instrumentation as reported in the literature. The authors point out that despite the purported advantages, delay in fabrication of the patient-specific guides, additional imaging, and occasional lack of optimal accuracy of the cutting guides leading to intraoperative up- or down-sizing of femoral components have lessened some of the early enthusiasm regarding patient-specific instrumentation.[13] [14] However, it is important to realize that although this novel technology appears promising, further refinements are necessary in future, to improve its accuracy and minimize waiting-times for production of the cutting blocks, before this becomes universally acceptable.

Recently, there have been considerable developments in the field of three-dimensional printing technology and its application in the fabrication of cementless knee arthroplasty components.[2] [3] [4] The use of this technology, also known as additive manufacturing, have led to the production of lower extremity arthroplasty implants with varying surface textures, three-dimensional geometries, graduated porosities, and optimal mechanical strength and stiffness.[4] Banerjee and co-authors have extensively described in their review these modern fabrication technologies, their advantages, recent developments, and some of the current concerns with this manufacturing technology. Furthermore, these authors have also discussed some of the putative benefits of this layered manufacturing technology that include its speed and ability to produce components without the need for conventional techniques of casting, machining, and tooling for implant manufacturing.[4] These manufacturing advances together with the use of bioactive coatings may potentially enhance the osseointegration to cementless implants and have led to resurgence in the use of cementless fixation in TKA.

The philosophy of the use of press-fit fixation in TKA is based on the concept that a fully osseointegrated implant will have a durable implant survivorship with an extremely low rate of aseptic loosening. Although long-term outcomes of the newer generation of cementless implants manufactured with modern fabrication methods are currently unavailable, the early clinical and radiographic outcomes appear promising. Cherian and co-authors have provided the readers with an extensive review on the history, clinical and radiographic outcomes of some of the early and newer designs, and have discussed the cost-effectiveness of using press-fit designs in TKA.

In addition, there has been recent impetus for the development of bicruciate preserving TKA implants with the goal of replicating natural knee kinematics, enhancing functional outcomes, and enabling patients to achieve high activity levels, and thereby to improve patient satisfaction.[15] [16] [17] Cherian and co-authors have discussed in their article that due to various concerns including technical difficulties, lack of optimal visualization during bone cuts, inadequate tibial component fixation, questionable functional benefit, and unpredictable functional viability of retained ligaments, bicruciate preservation during TKA have not been popular.[16] However, with the development of newer designs, some of the goals of improved kinematics and functional benefits with bicruciate retention may in fact become a reality in future.

The purpose of this special supplement is to provide an update to practicing orthopaedic surgeons about some of the recent technologies in the field of TKA and that hopefully it will stimulate further research on these topics in the future.