AAOS Now

Published 1/1/2012

Knee Society Introduces New Knee Scoring System

Updated outcomes instrument now available

For more than 20 years, The Knee Society’s Knee Scoring System (KSS) has served as a simple, objective way to measure a patient’s functional ability before and after total knee arthroplasty (TKA). Although it has served patients and researchers well, “Contemporary TKA patients often have different expectations, demands, and functional requirements than those of previous generations,” said Giles R. Scuderi, MD, who chaired the committee to update the instrument.

The new KSS has both preoperative and postoperative versions with both patient and surgeon sections. In the preoperative instrument, for example, patients supply demographic information, and complete questions relating to their symptoms (pain measures), knee function, satisfaction with their current functional activities, and expectations of the results of the TKA. The surgeon completes information on Charnley functional classification and objective information on the alignment, instability, and range of motion of the knee.

“A great deal of work went into determining the functional component,” said Dr. Scuderi. “Over the last 4 years Knee Society members from 18 institutions in the United States and Canada contributed more than 500 cases to the development of the new scoring system, which was validated and approved by a multidisciplinary team of arthroplasty surgeons, research scientists, epidemiologists, and statisticians. The new score provides sufficient flexibility and depth to capture the diverse lifestyles and activities of our current patients.”

In addition to questions about standard activities such as walking on an uneven surface or climbing a flight of stairs, the instrument also asks about discretionary activities that are important to the patient. These include both recreational and workout activities. The postoperative version asks patients to compare their initial expectations with current reality for pain relief, activities of daily living, and discretionary (leisure, recreational, and sports) activities.

The development committee—Dr. Scuderi, Robert B. Bourne, MD; James B. Benjamin, MD; Jess H. Lonner, MD; W. Norman Scott, MD; and Philip C. Noble, PhD—were careful to retain portions of the original system to maintain the integrity of the prior version.

“We as surgeons are becoming more responsible for reporting patient outcomes—and these outcomes will help determine how these procedures will be reimbursed in the future,” noted Dr. Scuderi. “This broad applicability of this new scoring system will enable us to measure and report those outcomes across sex, age, activity level, and implant type.”

The new scoring system is available through application on The Knee Society website, www.kneesociety.org