Clinical Sciences/Health Conditions
Ryuta Yoshizawa, BS
Physical Therapist
Department of Rehabilitation,University of Tsukuba Hospital
Tsukuba, Ibaraki, Japan
Naoya Kikuchi, PhD
Assistant Professor
Department of Orthopedic Surgery, Institure of Meddicine, University of Tsukuba
Tsukuba, Ibaraki, Japan
Ayumu Haginoya, BS
Physical Therapist
Department of Rehabilitation, University of Tsukuba Hospital
Tsukuba, Ibaraki, Japan
Kaichi Ozone, PhD
Assistant Professor
Department of Physical Therapy, Niigata University of Health and Welfare
kita, Niigata, Japan
Yuichiro Soma, PhD
Assistant Professor
Department of Orthopedic Surgery, Institure of Meddicine, University of Tsukuba
Tsukuba, Ibaraki, Japan
Ryosuke Tsutsumi, MD
Assistant Professor
Department of Orthopedic Surgery, Institure of Meddicine, University of Tsukuba
Tsukuba, Ibaraki, Japan
Koichi Iwai, PhD
Professor
Ibaraki Prefectural University of Health Sciences
Ami-machi, Ibaraki, Japan
Kimihisa Ishikawa, BS
Physical Therapist
Department of Rehabilitation,University of Tsukuba Hospital
Tsukuba, Ibaraki, Japan
Akihiro Kanamori, PhD
MD
Department of Orthopedic Surgery, Institure of Meddicine, University of Tsukuba
Tsukuba, Ibaraki, Japan
This study aimed to longitudinally assess periarticular knee muscle thickness and echo intensity after total knee arthroplasty (TKA) using ultrasound, examine their relationship with quadriceps strength, and identify sarcopenia and factors affecting delayed muscle recovery.
This prospective observational study was conducted at a single center between January 2024 and May 2025. 21 patients (6 males, 15 females; mean age 71.7 ± 5.69 years; BMI 26.34 ± 5.3 kg/m²) undergoing primary TKA were analyzed. Ultrasound of the rectus femoris (RF) and vastus intermedius (VI) was performed preoperatively and at 1 week, 2 weeks, 1 month, and 3 months postoperatively. Isokinetic strength testing was performed preoperatively and at 1 and 3 months at 180°/s and 300°/s. Quadriceps and hamstring recovery were assessed using the Limb Symmetry Index. Data were analyzed using a generalized linear mixed model, and correlations were assessed with Pearson’s coefficients. Significance was set at p < 0.05.
6 patients were diagnosed with sarcopenia.RF and VI thickness was lowest at 1 month, with VI remaining below baseline at 3 months. No significant differences in muscle thickness were observed between sarcopenia and non-sarcopenia groups. RF echo intensity was significantly lower in sarcopenia patients at 1 week (p = 0.018). BMI significantly influenced both muscle thickness and echo intensity. Hamstring strength was lower in sarcopenia patients at 3 months at 180°/s (p = 0.001) and 300°/s (p = 0.031). VI thickness correlated with quadriceps strength at 1 month (180°/s, r = 0.508, p = 0.026), and RF thickness correlated with quadriceps strength at 3 months at 180°/s (r = 0.537, p = 0.048) and 300°/s (r = 0.615, p = 0.019).
