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 Table of Contents  
Year : 2022  |  Volume : 36  |  Issue : 1  |  Page : 46-48

Effect of intramuscular electrical stimulation of articularis genu muscle with mirror therapy on anterior knee pain in a patient with knee osteoarthritis

1 MYAS-GNDU Department of Sports Sciences and Medicine, Guru Nanak Dev University, Amritsar, Punjab, India
2 Department of Physiotherapy, I.T.S Institute of Health and Allied Sciences, Muradnagar, Uttar Pradesh, India

Date of Submission08-Feb-2022
Date of Decision15-Mar-2022
Date of Acceptance17-Mar-2022
Date of Web Publication25-Apr-2022

Correspondence Address:
Dr. Sarik Chaudhary
MYAS-GNDU Department of Sports Sciences and Medicine, Guru Nanak Dev University, Amritsar, Punjab
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/ijpn.ijpn_16_22

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Knee osteoarthritis (OA) is a degenerative condition that can develop in people who have quadriceps muscle weakness. Knee OA is more likely to develop in people who have weak quadriceps muscles, which extend the knee. Dysfunction of articularis genu muscle (AGM) is thought to be a cause of anterior knee pain in patients having OA of the knee joint. Herein, we report a case of anterior knee pain caused due to the dysfunction of AGM in a 41-year male who was initially treated with physical therapy, and it failed to ease the patient's problems completely. Intramuscular electrical stimulation (IMES) along with mirror therapy relieved his symptoms with no recurrence till 2 months of follow-up. IMES of the AGM combined with mirror therapy can be a viable therapeutic option for muscle reeducation and anterior knee pain.

Keywords: Anterior knee pain, intramuscular electrical stimulation, knee osteoarthritis

How to cite this article:
Chaudhary S, Sharma MK. Effect of intramuscular electrical stimulation of articularis genu muscle with mirror therapy on anterior knee pain in a patient with knee osteoarthritis. Indian J Pain 2022;36:46-8

How to cite this URL:
Chaudhary S, Sharma MK. Effect of intramuscular electrical stimulation of articularis genu muscle with mirror therapy on anterior knee pain in a patient with knee osteoarthritis. Indian J Pain [serial online] 2022 [cited 2023 Mar 31];36:46-8. Available from: https://www.indianjpain.org/text.asp?2022/36/1/46/343824

  Introduction Top

Osteoarthritis (OA) is a chronic degenerative condition of the knee joint involving wear and tear of articular cartilage and is a leading cause of disability worldwide. It is now recognized that OA is caused by a multidimensional and complex interplay of constitutional and mechanical elements such as joint integrity, hereditary predisposition, local inflammation, mechanical pressures, and cellular and biochemical processes. Weakness of the knee extensor muscles (quadriceps) is also linked to an increased risk of developing OA knee.[1],[2] Dysfunction of articularis genu muscle (AGM), which is regarded as the fifth head of the quadriceps, has been found in instances of knee OA.[3],[4] This dysfunction causes a reduction in the retractable distance of the suprapatellar bursa, which leads to its entrapment between the patella and femoral condyles during knee extension in individuals with knee OA and may cause anterior knee pain.[3] The latest researches show that intramuscular electrical stimulation (IMES) of muscles with mirror therapy causes an increase in motor unit recruitment and motor reeducation.[5] Hence, it may be utilized as a therapeutic option for muscle dysfunction.[6],[7],[8] We have described a case that was treated with the combination of IMES and mirror therapy to alleviate motor dysfunction of AGM and anterior knee pain in OA of the knee joint.

  Case Report Top

A 41-year-old male presented to our outpatient department with a 3-month history of anterior knee pain in his left lower extremity. During the subjective assessment, the patient reported that walking and stair climbing were aggravating factors, and there was no history of trauma. Previous history of treatment received by the patient included interferential therapy, moist heat, and exercise. However, there was no improvement in the patient's symptoms, and all the therapies failed to completely ease the patient's problem. During the initial pain assessment, the patient reported that his pain levels were 3, 6, and 8 on a numeric pain rating scale of 0–10 during rest, walking, and stair ascending, respectively. On physical examination, mild crepitus was felt during patellar gliding. The WOMAC knee OA scale was 75/96. The patient's radiographic test revealed that he had Grade-2 OA (Kellgren–Lawrence OA grading). Following the examination, we made the probable diagnosis of AGM dysfunction of the left knee.

Intramuscular electrical stimulation with mirror therapy

IMES along with mirror therapy was utilized to address AGM dysfunction. A mirror was placed between the legs facing the unaffected extremity, and the patient's affected leg was fastened with the couch's leg using a Velcro strap to avoid any unnecessary movement [Figure 1], while the needle was being inserted in the muscle and throughout the treatment to avoid any adverse event caused by needle movement or muscle contraction. Two dry needles (40 mm length and 0.25 mm diameter) were inserted perpendicularly, approximately 2 cm proximal to the superior border of the patella for IMES of the AGM [Figure 2]. To excite the motor unit, to induce muscular contraction, and to facilitate the release of endogenous opioid[9] [Figure 3], a biphasic low-frequency (2 Hz) electrical current was passed through alligator clips into the needles for a duration of 10 min, and the intensity of the electrical current was modulated as per the patient's comfort. At the same time, the patient was instructed to perform knee flexion and extension movements with the unaffected limb while looking in the mirror to promote motor reeducation [Figure 4]. The patient received a total of three treatment sessions on alternate days for a week.
Figure 1: Position of the affected extremity

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Figure 2: Intramuscular electrical stimulation of articularis genu muscle

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Figure 3: Possible mechanisms for the analgesic effects of Intramuscular electrical stimulation. Opioid peptides and opioid receptors involved in analgesia elicited by low frequencies (2 Hz) Intramuscular electrical stimulation. β-End: β-endorphin; Em: Endomorphin; Enk: Enkephalins

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Figure 4: Position of unaffected extremity

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Clinical outcome

The patient experienced a relief in pain when resting (0/10), walking (0/10), stair climbing (1/10), and the score of WOMAC scale for OA was reduced to 25/96 after the treatment was completed.


OA is a degenerative disease of the knee joint that occurs over time. Age, bone malalignment, muscle dysfunction, etc., all are risk factors for OA.[3] One of the risk factors linked to the symptoms and progression of knee OA is quadriceps muscle weakness.[3],[4] The AGM is a tiny muscle that is located between the vastus intermedius and the prefemoral fat pad. It originates from the anterior surface of the distal femur and inserts into the suprapatellar bursa. During knee extension, the AGM is assumed to retract and elevate the suprapatellar bursa, preventing it from being entrapped between the patella and the femur.[10] As a result, AGM dysfunction is thought to be a cause of anterior knee pain. In the OA individuals, atrophic alterations and dysfunctions in the AGM were found, which were linked to reduced knee range of motion and anterior knee pain.[1],[2] In those with knee OA, the AGM is a key treatment target, and improving its contraction may help with the symptoms.[3] IMES combined with the mirror therapy may be utilized to promote motor unit recruitment, reeducation of the AGM, as well as to treat muscle dysfunction and alleviate OA symptoms such as anterior knee pain.[5]

Mechanism of action

Although no definitive conclusions can be made due to the absence of control, our results support the use of IMES with low-frequency (2 Hz) current as it facilitates the release of endogenous opioids such as enkephaline, β-endorphin, and endomorphin, which promotes analgesia.[9] IMES also increases recruitment of AGM and promotes retraction and elevation of the suprapatellar bursa, preventing the bursa from being entrapped between the patella and the femur. Mirror therapy help in motor reeducation of AGM dysfunction. IMES combined with mirror therapy may be employed in the early stages of OA to produce analgesia, excite motor units, and encourage muscle contraction while also providing motor reeducation of the AGM simultaneously.

  Conclusion Top

A patient with OA having symptoms of anterior knee pain with exacerbating factors including walking and stair climbing was described in this case study. The previous treatment comprised exercise and electrotherapy, but these interventions were unsuccessful, and the symptoms worsened with time. We then applied IMES along with mirror therapy on the AGM to relieve pain, improve dysfunction, and enhance functional mobility. Although a randomized controlled research is required to investigate the favorable impact of IMES of the genu articularis muscle in anterior knee pain due to OA, this case illustrates that IMES of the AGM combined with mirror therapy can be a viable therapeutic option for muscle reeducation and anterior knee pain due especially in Kellgren–Lawrence Grade-2 OA.

Patient consent

The patient provided written informed consent for anonymized patient information to be published in this article.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient has given his consent for his images and other clinical information to be reported in the journal. The patient understands that name and initials will not be published, and due efforts will be made to conceal the identity, but anonymity cannot be guaranteed.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.

  References Top

Glass NA, Torner JC, Frey Law LA, Wang K, Yang T, Nevitt MC, et al. The relationship between quadriceps muscle weakness and worsening of knee pain in the MOST cohort: A 5-year longitudinal study. Osteoarthritis Cartilage 2013;21:1154-9.  Back to cited text no. 1
Øiestad BE, Juhl CB, Eitzen I, Thorlund JB. Knee extensor muscle weakness is a risk factor for development of knee osteoarthritis. A systematic review and meta-analysis. Osteoarthritis Cartilage 2015;23:171-7.  Back to cited text no. 2
Saito A, Okada K, Saito I, Kinoshita K, Seto A, Takahashi Y, et al. Functional status of the articularis genus muscle in individuals with knee osteoarthritis. J Musculoskelet Neuronal Interact 2016;16:348-54.  Back to cited text no. 3
Lee JH, Kim K, Chung SG. Intra-articular pressure characteristics of the knee joint: An exploratory study. J Orthop Res 2021;10.1002/jor.25236. [doi: 10.1002/jor.25236].  Back to cited text no. 4
Lee D, Lee G, Jeong J. Mirror therapy with neuromuscular electrical stimulation for improving motor function of stroke survivors: A pilot randomized clinical study. Technol Health Care 2016;24:503-11.  Back to cited text no. 5
Ji SG, Cha HG, Kim MK, Lee CR. The effect of mirror therapy integrating functional electrical stimulation on the gait of stroke patients. J Phys Ther Sci 2014;26:497-9.  Back to cited text no. 6
Sheffler LR, Chae J. Neuromuscular electrical stimulation in neurorehabilitation. Muscle Nerve 2007;35:562-90.  Back to cited text no. 7
Tashiro S, Mizuno K, Kawakami M, Takahashi O, Nakamura T, Suda M, et al. Neuromuscular electrical stimulation-enhanced rehabilitation is associated with not only motor but also somatosensory cortical plasticity in chronic stroke patients: An interventional study. Ther Adv Chronic Dis 2019;10:1-13.  Back to cited text no. 8
Han JS. Acupuncture: Neuropeptide release produced by electrical stimulation of different frequencies. Trends Neurosci 2003;26:17-22.  Back to cited text no. 9
Grob K, Gilbey H, Manestar M, Ackland T, Kuster MS. The anatomy of the articularis genus muscle and its relation to the extensor apparatus of the knee. JB JS Open Access 2017;2:e0034.  Back to cited text no. 10


  [Figure 1], [Figure 2], [Figure 3], [Figure 4]


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