Osteoarthritis (OA) is a chronic degenerative disorder of multifactorial cause characterized by the hypertrophy of bone at the margins, loss of articular cartilage, subchondral sclerosis, and biochemical and morphological changes in the synovial membrane and joint capsule [1]. Clinically, it is characterized by pain in the affected joint, tenderness, stiffness, crepitus, and restricted movement, occasionally accompanied by effusion and varying degrees of local inflammation, which leads to decreased quality of life [2]. Initially, pain in osteoarthritis is related to functional activities, and in the later stages, pain might be constant in nature. It can affect any joint in the body but most commonly affects the hip, knee, and joints of the hand, foot, and spine. The knee is the second main joint affected by osteoarthritis, next to the hip joint [3].

The prevalence of osteoarthritis of the knee (OAK) increases with age, and OAK generally affects women more frequently than men. However, in some cases, it may also affect the younger population [4]. Globally, 3.3% to 3.6% of the population is affected by OAK, making it the 11th most debilitating disease. It is the most common joint disease, with a prevalence of 22% to 39% in India [5]. OAK affects approximately 10-12% of the population over the age of 65 years [6]. The risk factors for OAK are old age, female sex, being overweight, injury to the knee, repetitive knee joint use, sports activities or any physical activities that injure the knee joint, and muscle weakness [7].

Conservative management, such as analgesics and nonsteroidal anti-inflammatory drugs, relieves symptoms and re-establishes the function of the knee joint [8]. However, various adverse events, such as bleeding, perforation, gastric ulceration [9], and increased risk of cardiovascular disease [10], limit the use of these drugs. Hence, there has been an increased focus on nonpharmacological interventions among both doctors and patients with OAK [11].

Acupuncture is a traditional Chinese medicine that works based on the manipulation of vital energy called “Qi” or “Chi”. The vital energy passes through meridians via acupuncture points. It can be channelized or balanced by providing external stimulation either through needles or manual pressure applied over the acupuncture points. According to the traditional acupuncture philosophy, in healthy individuals, energy circulates within meridians present throughout the body. Any blockage or excess in the energy flow can cause pain or poor health. According to the World Health Organization (1991), the classical acupuncture points can be stimulated to balance energy flow in the body and thereby improve health [12].

Numerous studies have shown the beneficial effects of acupuncture, which include pain relief [13,14], improved quality of life [15], reduced anxiety [16], reduced depression [17], and improved brain function [18]. A systemic review and meta-analysis concluded that acupuncture may reduce knee pain and improve physical function in patients with OAK [19].

Acupuncture point – liver 7 (LR 7): Chinese name, Xiguan; Xi means knee and guan means joint. In the textbook on advanced acupuncture therapy by Agarwal et al., LR 7 was indicated for knee joint pain [20], but there was no scientific evidence available to prove the efficacy of LR 7 for chronic knee joint pain and range of motion. To the best of our knowledge, no previous study has been performed on the role of LR 7 in managing OAK. Therefore, we conducted this study to determine whether a single acupuncture point (LR 7) can alleviate knee pain and improve the range of motion of the affected knee.

1. Study setting

This single group pre-post study was conducted in the Outpatient Department of Government Yoga and Naturopathy Medical College and Hospital, Arignar Anna Hospital, Chennai. A total of 35 participants were recruited after they fulfilled the inclusion and exclusion criteria and provided signed informed consent.

2. Eligibility criteria

We included participants aged between 40 and 65 years, of both genders, with knee pain for the last 6 months, X-ray data suggesting mild to moderate degeneration, unilateral knee joint pain and restriction, and who were willing to participate in the study and provide informed consent. We excluded patients who had knee deformity, surgery on the affected knee, bilateral affected knee joints, or who were receiving analgesic or steroid medications for the past 1 month.

3. Ethical considerations

Institutional ethical committee (IEC) approval (No. 009/GYNMC/IEC/2018) was obtained before the first participant was recruited.

4. Intervention

The half-cun acupuncture needle was inserted into the affected knee joint approximately 2 mm vertically to the acupuncture point Liver-7 (LR 7, XIGUAN), which is located at the junction of the shaft and medial condyle of the tibia, for 20 minutes, with 5 sessions weekly for 2 weeks (10 sessions). Baseline data were collected before the intervention, and postintervention data were collected after the completion of 10 sessions of acupuncture. Acupuncture needling was performed by a naturopathy and yoga doctor, who is an expert in the field of acupuncture.

5. Outcome variables

The WOMAC was developed at the Western Ontario and McMaster Universities in 1982. It is a self-administered questionnaire widely used in the evaluation of knee and hip osteoarthritis. It consists of 24 items and is divided into 3 subscales: pain (5 items), stiffness (2 items), and physical function (17 items). The test questions are scored on a scale of 0-4, with 0 = None, 1 = Mild, 2 = Moderate, 3 = Severe, and 4 = Extreme. The scores for each subscale are summed up, with a score ranging from 0-20 for pain, 0-8 for stiffness, and 0-68 for physical function. The sum of the scores for all three subscales gives a total WOMAC score. Higher scores on the WOMAC indicate worse pain, stiffness, and functional limitations [21]. In the present study, the WOMAC was administered before the intervention and after the completion of 14 sessions of acupuncture.

The knee is a modified hinge joint that primarily moves during flexion and extension and has mild internal and external rotation during flexion. A goniometer is an instrument used to measure the angles of any joint. It shows angles from zero to 180 or 360 degrees. Full extension of the knee joint, which is the straight knee, measures 0 degrees, and complete flexion of the knee joint, which is the flexed knee, measures 135 degrees. Functional activities require 0 to 120 degrees of motion at the knee. In the present study, we measured the degree of maximum active flexion and extension in the supine lying state of the affected knee before and after 10 sessions of acupuncture on LR 7.

6. Statistical analysis

Data analysis was performed using the Statistical Package for Social Sciences (SPSS) software version 27. We selected a group of participants (n = 35) from the population to assess whether acupuncture treatment for chronic OAK relieves pain and stiffness and improves functional activities. Pre-trial and post-trial results were compared using paired t-tests.

We collected 35 participants’ data. The median age was 55 (standard deviation [SD] 6.7) years, and the majority of the participants were female (n = 28; 80%). Among the female participants, 20 (57.1%) had reached menopause. Most of the participants were obese (n = 33; 94.3%), and the majority of knee involvement was “left” (n = 20; 57.1%) (Table 1).

BMI = Body mass index; SD = Standard deviation..

&md=tbl&idx=1' data-target="#file-modal"">Table 1

Demographic characteristics of study participants.

Characteristics	Number	Proportion (%)
Age (Mean ± SD)	55 ± 6.7
Gender
Male	7	80.0
Female	28	20.0
Menopause
Yes	20	57.1
No	8	22.9
BMI
Over weight	2	5.7
Obese	33	94.3
Knee involvement
Left	20	57.1
Right	15	42.9

BMI = Body mass index; SD = Standard deviation..

We performed Student’s t-test to assess the difference between the pre- and post-intervention scores. There was a significant difference in the WOMAC score (49.3 vs. 30) and range of motion score during knee flexion (109.9 vs. 114.9) and knee extension (15.8 vs. 8.8) before and after the intervention. We found that there was a significant reduction in pain and improvements in range of motion (< 0.05) (Table 2). A paired sample t-test was conducted to determine if there was a difference between the mean range of motion flexion pre-test and range of motion flexion post-test at the level of significance = 0.05 (α = 0.05). By default, the output result of SPSS is a two-tailed test. We conducted a one-tailed test. The easiest way to convert two-tailed results to one-tailed results is to divide the p-value in half. Therefore, we obtained p = 0.000 < 0.05 (α = 0.05).

WOMAC = Western Ontario and McMaster Universities Arthritis Index; ROM = range of motion; p = probability; SD = standard deviation..

&md=tbl&idx=2' data-target="#file-modal"">Table 2

Pain and range of motion differences pre and after interventions.

	Pre-intervention (Mean ± SD)	Post-intervention (Mean ± SD)	Mean difference	p-value
WOMAC	49.7 ± 11.9	30.0 ± 9.6	19.7	0.001
ROM knee flexion	109.9 ± 6.7	114.9 ± 9.7	–5.0	0.003
ROM knee extension	15.8 ± 5.7	8.8 ± 5.1	6.9	0.001

WOMAC = Western Ontario and McMaster Universities Arthritis Index; ROM = range of motion; p = probability; SD = standard deviation..

There was a significant difference in the two test scores following the treatment according to the WOMAC pre-test (M = 49.7, SD = 11.9) and WOMAC post-test (M = 30.0, SD = 9.6) (mean difference: 19.826, p = 0.000). We also found that there was a significant difference in range of motion scores between pre- and post-intervention during knee flexion (109.9 vs. 114.9) and extension (15.8 vs. 8.8) (Table 2).

Acupuncture is a traditional Chinese medicine used as a complementary and alternative therapy for various medical conditions, such as nausea [22], pain [14], allergies [23], breathing difficulty [24], depression [25], dyspepsia [26], and even tobacco use [27]. In the present study, a single acupuncture point (LR 7) for 10 sessions on the affected knee significantly improved the WOMAC scores. This improvement in the WOMAC scores was associated with a reduction in pain, stiffness, and functional disability. According to Melzack and Wall in 1965, in the gate control theory of pain, pain impulses are passed from peripheral primary afferent neurons to secondary neurons in the substantia gelatinosa in the dorsal horn of the spinal cord via the dorsal root ganglion. These impulses are controlled and transmitted to the thalamus of the brain through ascending tracts, where they synapse with third-order neurons and conduct projections to various parts of the cortex, producing pain responses. In the substantia gelatinosa, inhibitory interneurons block nociceptive signals on their way to the brain. This phenomenon occurs in daily life when people rub the spot where an injury has occurred [28].

Possible mechanisms by which acupuncture reduces pain may involve external stimuli applied to the area where pain originates. In our study, the LR 7 acupuncture point location was in the proximity of the knee joint, and needling was performed only on the affected knee. The decrease in knee pain in the present study may be due to the pain gate control theory, as proposed by Melzack and Wall. Several studies have shown that electroacupuncture can significantly increase the expression of β-endorphins in local arthritis tissues and thereby increase the activity of the body’s endogenous opioid system, which can reduce pain perception [29].

According to a recent research trial, chronic knee pain does not improve with once-weekly needle and laser acupuncture treatments over a 12-week period [30]. Another study revealed that receiving needle acupuncture twice a week for eight weeks significantly reduced pain in patients with OAK [31]. According to the findings of the previously mentioned studies, having more sessions per week produces better outcomes. Consequently, for a total of two weeks, our study included five sessions per week.

Multiple systematic reviews and meta-analyses also support the findings of the present study, and it was concluded that acupuncture can be considered an effective intervention for OAK [32,33]. A study conducted by Berman et al. [34] in 1999 concluded that after 12 weeks of acupuncture (St 35, St 36, Sp 9, and GB 34), all the subscales of the WOMAC significantly improved. In 2005, another study by Witt et al. concluded that 12 sessions of acupuncture for 8 weeks improved the pain and function of the knee joint. Similarly, in our study, pain significantly improved both statistically and clinically.

The characteristic feature of OAK is pain, and restricted knee flexion and extension may be due to pain or degenerative changes in the affected knee [2]. One case study showed that 6 weeks of once-weekly acupuncture at St 34, St 36, Sp 9, or Sp 10 for 30 minutes of needling significantly improved knee range of motion [35]. This case report supports our current study that acupuncture helps increase the degree of knee flexion and extension.

The present single-group pre-post study, without a control group, showed that the insertion of an acupuncture needle at acupuncture point LR 7 for a duration of 20 minutes for 10 sessions significantly improved the degree of pain and increased the knee range of motion, flexion, and extension.

1. Strengths

To the best of our knowledge, this is the first study on the effects of a single acupuncture needle (LR 7) in the management of pain and mobility due to OAK. No adverse events or side effects were reported during or after acupuncture in any of the participants. There were no dropouts from the study, which shows that acupuncture has compliance among the public. In this study, the intervention was administered by a single yoga and naturopathy physician, who holds a Doctor of Medicine (M.D.) degree in acupuncture.

2. Limitations

There were certain limitations noted in the study. (a) The study did not include a control or sham acupuncture group; due to the lack of a control group, it is difficult to conclude that LR 7 alone helps manage pain in OAK. (b) There was no comparison with other conventional management modalities for OAK. (c) Since this was a pilot study, no sample calculations were performed; therefore, a small sample size was used. (d) This study was planned to observe only the short-term effect of LR 7 on OAK; it does not answer the question of long-term effects. (e) There was no follow-up.

3. Direction for further research

Further studies with larger sample sizes and a randomized controlled design are warranted. Long-term effects or follow-up and variables such as endogenous opioid tests and neuroimaging can be included.

In conclusion, 10 sessions of acupuncture at point LR 7 for 20 min each may reduce knee pain, increase knee flexion and extension, and ameliorate OAK to improve the quality of life in elderly people with OAK. Therefore, acupuncture can be an adjuvant therapy for the management of OAK.

We are grateful to principal and faculities of government of yoga and naturopathy medical college and hospital for their support. We thank head of the acupuncture and energy medicine department for their guidance and we also thank students, parents and colleagues for their moral support.

M. Periyachishreepriya and P. Prabu are involved in conceptualization and data collection. P. Kumaresan and A. Naveena were involved in manuscript drafting. M. Sendhilkumar involved in statistical analysis. P. Kumaresan and M. Sendhilkumar were involved in reviewing the manuscript and editing. All authors approved the final version of the manuscript.

The authors declare no conflict of interest.