2025 ISAKOS Biennial Congress Paper
Evaluation Of Preoperative Factors Affecting Postoperative Daily Activity Immediately After Total Knee Arthroplasty
Tomofumi Kinoshita, MD, PhD, Toon, Ehime JAPAN
Tatsuhiko Kutsuna, MD, PhD, Toon, Ehime JAPAN
Kunihiko Watamori, MD, Toon, Ehime JAPAN
Takashi Tsuda, Toon City, Ehime JAPAN
Yusuke Horita, MD,, Toon, Ehime JAPAN
Kazunori Hino, MD, PhD, Toon, Ehime JAPAN
Masaki Takao, Prof., Toon, Ehime JAPAN
Department of Orthopaedic Surgery, Ehime University Graduate School of Medicine, Toon, Ehime, JAPAN
FDA Status Cleared
Summary
Our study using a wearable physical monitor demonstrated that adequate preoperative flexion muscle strength has a significant impact on moderate physical activity levels immediately after total knee arthroplasty.
Abstract
Background
The evaluation of clinical outcomes in total knee arthroplasty (TKA) has traditionally focused on radiographic assessments and patient-reported outcome measures (PROMs). However, it remains unclear whether these results enable surgeons to accurately assess a patient’s actual improvement in daily life activities. The aim of this study is to investigate the relationship between PROMs and a patient’s actual daily movement as evaluated using a wearable physical monitor (WPM), and to identify factors associated with improvements in daily life activities following TKA.
Methods
We evaluated 20 knees of Japanese population that underwent posterior-stabilized TKA (Persona posterior stabilized TKA, Zimmer). The mean age was 77.3±8.0. Daily life movement was assessed using WPM one month before TKA and from 4 to 6 weeks after TKA. We measured step count, metabolic equivalents (METs), and total activity using WPM, and calculated the mean value of each status per day. For PROMs, we utilized the 2011 Knee Society Score (KSS) both before and 6 weeks after TKA. Additionally, limb muscle strength was evaluated using the Cybex system, preoperatively.
Results
The mean daily total activity at 6 weeks post-TKA was 74% of the preoperative status. Preoperative functional activity score in KSS showed no correlation with each status obtained by WPM after TKA. Preoperative flexion muscle strength on the affected side correlated with the mean time spent in 6 and 7 METs activity post-TKA (ρ=0.60, 0.65). Moreover, preoperative flexion muscle strength on the contralateral side correlated with the mean time spent in 4 and 7 METs activity post-TKA (ρ=0.59, 0.61).
Conclusion
Preoperative PROMs did not directly predict a patient’s daily life movements after TKA. Total activity recovered to 74% of the preoperative status by 6 weeks post-TKA in elderly Japanese population. Adequate preoperative flexion muscle strength has a significant impact on moderate physical activity levels immediately after TKA.