As a common chronic joint disease in orthopaedics, knee osteoarthritis (KOA) is mainly aetiologically caused by degenerative changes in the articular cartilage and the resulting hyperosteogeny. This results in complications, including knee pain, stiffness, and dysfunction. Given the improvements resulting from new biomaterials and surgical techniques, total knee arthroplasty (TKA) is now a first-choice treatment for patients with severe KOA for improving their quality of life [
1,
2]. Compared with non-surgical treatment, TKA significantly relieves pain and promotes functional improvement in patients with severe KOA [
3]. More than 700,000 TKA procedures are performed annually in the USA to relieve KOA-related pains and disability, which is expected to reach 3.5 million per year by 2030 [
4]. Despite the objective post-TKA improvements in knee function and its imaging parameters, 19–23% of post-TKA patients still report dissatisfaction at the 6-month follow-up [
5,
6]. Compared with healthy adults, there are post-TKA deficits in lower limb muscle strength, which reduces walking distance and stair climbing speed [
7,
8]. Lack of muscle strength increases the risk of falling, which makes the patients lose their independence. Muscle strength rehabilitation of the knee extensor and flexor is essential for functional improvement of patients with KOA since knee stability is primarily supported by the soft tissue of the quadriceps femoris and hamstring. A post-TKA decrease in the strength of the quadriceps femoris and hamstring [
9‐
12], which is associated with decreased function [
13,
14], has been reported. Moreover, there have been reports of difficulty with post-TKA muscle strength recovery. For example, surgical incision pain reduces the patient’s ability to exercise. In the first post-TKA month, the strength of the quadriceps femoris decreased by 60% [
15]. Although the strength of the quadriceps improves over time, approximately 30% of post-TKA patients have reported deficits at > 2 postoperative years compared with healthy adults [
16]. Immediately after the operation, the hamstring strength has been reported to reduce by 50% [
11,
17]. Previous studies have reported TKA-related weakness and gait biomechanical damage to the quadriceps femoris and hamstring that may last for several years [
18,
19]. Standardized physiotherapy is beneficial towards muscle functional improvement [
20]. Moreover, neuroregulatory techniques, including neuromuscular electrical stimulation and electroacupuncture (EA), have become increasingly popular as post-TKA rehabilitation therapy [
21]. Effective post-TKA neuroregulatory techniques can enhance lower limb muscle strength, which fast-tracks rehabilitation and reduces the financial burden of patients [
22].
EA is primarily recommended for pain modulation and has been shown to enhance muscle strength [
23,
24]. However, there have been few randomized controlled trials on post-TKA patients with limited evidence regarding the EA effect on lower limb muscle strength. Therefore, we designed a double-blinded, randomized, and placebo-controlled trial to investigate the EA effects on lower limb muscle strength in post-TKA patients, specifically, during the early postoperative period.