This Article Full Text Full Text (PDF) Letters to the Editor: Submit a response Alert me when this article is cited Alert me when Letters to the Editor are posted Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Add to My File Cabinet Download to citation manager Reprints and Permissions Google Scholar Articles by Emerson, R. H. Articles by Higgins, L. L. PubMed PubMed Citation Articles by Emerson, R. H., Jr. Articles by Higgins, L. L. Related Collections Adult Knee Social Bookmarking             What's this?

Unicompartmental Knee Arthroplasty with the Oxford Prosthesis in Patients with Medial Compartment Arthritis

¹ Texas Center for Joint Replacement, 5940 West Parker, Suite 100, Plano, TX 75093. E-mail address for R.H. Emerson: rhemerson{at}msn.com
Investigation performed at the Texas Center for Joint Replacement, Plano, Texas

Disclosure: In support of their research for or preparation of this work, one or more of the authors received, in any one year, outside funding or grants of less than $10,000 from Biomet. In addition, one or more of the authors or a member of his or her immediate family received, in any one year, payments or other benefits in excess of $10,000 or a commitment or agreement to provide such benefits from a commercial entity (Biomet). No commercial entity paid or directed, or agreed to pay or direct, any benefits to any research fund, foundation, division, center, clinical practice, or other charitable or nonprofit organization with which the authors, or a member of their immediate families, are affiliated or associated.

Methods: Fifty-five knees in fifty-one patients with medial compartment osteoarthritis had a unicompartmental replacement with an Oxford prosthesis. Evaluation included Knee Society clinical scores, radiographic evaluation, survivorship analysis, and modes of failure. The average duration of clinical follow-up was 11.8 years. Only two patients (three knees) were lost to follow-up.

Results: The mean postoperative Knee Society knee score and function score at the latest follow-up evaluation were 75 and 90 points, respectively. The overall alignment of the knee was restored to neutral, averaging 5.6° of valgus alignment. Forty-seven of the fifty-five knees had the mechanical axis crossing the central 50% of the tibial plateau. Seven knees had revision surgery, and six of them required conversion to a total knee prosthesis. The main reason for revision was the progression of arthritis in the lateral compartment, which occurred in four knees at an average of 10.2 years postoperatively. These four knees had not been overcorrected into excessive valgus at the time of the original surgery, and we found no correlation, with the numbers studied, between alignment and bearing size. Survivorship analysis showed that the rate of survival at ten years was 85% with failure for any reason as the end point, 90% with progression of lateral compartment arthritis as the end point, and 96.3% with component loosening as the end point.

Conclusions: With this unicompartmental knee arthroplasty, the mechanical limb alignment resulting from balancing the knee ligaments, accomplished without releasing them, was consistently through the center of the knee. Progression of arthritis in the lateral compartment was the most common reason for late failure in this series and was not related to the initial postoperative alignment.

Level of Evidence: Therapeutic Level IV. See Instructions to Authors for a complete description of levels of evidence.

CiteULike    Connotea    Del.icio.us    Technorati    What's this?

Stanford University Libraries' HighWire Press (TM) assists in the publication of JBJS Online.
Copyright © 2008 by The Journal of Bone and Joint Surgery, Inc. Online ISSN: 1535-1386.
The Journal of Bone and Joint Surgery®, JBJS®, JB&JS®, and eJBJS® are registered in the U.S. Patent and Trademark Office.