A group of researchers from Dalhousie University in Nova Scotia, Canada, asked the question: “What objectively measured data results in meaningful improvements in self-reported patient pain and function scores after total knee arthroplasty (TKA)?”
To determine how patient demographics, preoperative knee-joint biomechanics, and postoperative changes in knee biomechanics would affect self-reported pain and function after TKA, these investigators examined data from 46 individuals who were measured using 3D gait analysis one week before surgery and then one year after surgery.
Their results were published in the April-June 2020 edition of The Journal of Bone and Joint Surgery, “Individual Gait Features Are Associated with Clinical Improvement After Total Knee Arthroplasty.” This new study raises the possibility that the severity of knee osteoarthritis can be objectively assessed by measuring knee kinematics during gait.
Kathryn Young-Shand, Ph.D. candidate in the School of Biomedical Engineering at Dalhousie University and study co-author explained the purpose and hypothesis of the study to OTW, “In response to unacceptably long wait times, the need to appropriately select total knee arthroplasty patients for surgery is of significant importance within our orthopaedic community.”
“We sought to investigate if a patient’s gait features preoperatively (an objective metric of function) was associated with clinically meaningful improvements in self-reported pain and function after surgery, providing important information for preoperative candidate selection and expectation management. Further, we wished to investigate which gait function improvements from surgery were most associated with self-reported improvements, potentially motivating investigations into the efficacy of surgically targeting specific functional deficits.”
Where there any surprises?
“A unique finding of our study was preliminary evidence of a varus kinematic subgroup who may be susceptible to less pain and function improvements from standard arthroplasty. Specifically, larger reductions in stance-phase varus alignment was unfavorable among this preoperatively varus kinematic group. We believe these trends warrant further investigation; however, they support the interpretation that arthroplasty may be perceived differently by patients based on individual function patterns, and that standard approaches may not be optimal among all patient subgroups.”
What were the most important results?
“Our study contributes to the growing body of evidence that suggests variability in patient-reported outcomes may be partially explained by a combination of clinical and objectively measured knee-joint biomechanical factors.”
“Specifically, patients who present with more ‘severe’ objective gait patterns preoperatively tended to be associated with a larger potential for both objective and self-reported functional improvements. Further, we identified a unique subgroup of a kinematically varus individuals, who experienced less symptomatic gain from standard arthroplasty intervention.”
“Objective functional assessment preoperatively may aid in identifying the optimal functional state associated with patient-reported improvements and help identify individuals who might benefit from an individualized surgical approach. Our results also support the notion that TKA innovation needs to better address three-dimensional knee joint mechanics at the individual level, if it aims to enhance its ability to provide expected improvements for all patients.”
