Individuals with knee osteoarthritis are one of the groups most affected by musculoskeletal disorders and experience pain and mobility limitations that significantly limit their daily living activities. Quantitative sensory assessment in individuals with osteoarthritis plays a critical role in evaluating disease progression and treatment effectiveness by objectively measuring changes in sensory perception such as proprioception and nociception. These changes in sensory perception can negatively affect individuals' movement control and balance. In this context, evaluation of quantitative sensory parameters allows the development of more targeted and effective interventions in the rehabilitation processes of individuals with osteoarthritis.

Additionally, electromyographic evaluation in individuals with osteoarthritis analyzes muscle activation levels, providing a better understanding of the impairments in muscle functions of these individuals. EMG data helps to design rehabilitation programs individually by determining to what degree muscles are activated and which muscle groups are more affected. Decreased muscle activation or abnormal muscle activation in individuals with osteoarthritis can negatively affect joint stability and mobility. Therefore, EMG evaluations are an objective method to evaluate the effectiveness of treatment strategies aimed at restoration of muscle functions in individuals with osteoarthritis.

The quantitative sensory and EMG evaluations performed in this project aim to improve the quality of life of individuals by offering innovative approaches in the clinical management of individuals with osteoarthritis. Therefore, these evaluations are of critical importance for the original value and scientific contribution of our project. For these reasons, the selection of individuals with osteoarthritis and the detailed evaluations made on these individuals and its connection with the methods can be considered as the innovative and original aspect of our project.

The aim of this study is to investigate the effect of the Mulligan movement mobilization concept on quantitative sensory parameters, pain and muscle activation levels in patients with knee osteoarthritis.

Osteoarthritis is a degenerative disease that occurs especially in weight-bearing joints, characterized by a decrease in joint space due to progressive cartilage loss, subchondral sclerosis and osteophyte formations (Martel et al., 2016). Although OA is also seen in the hip, spine and hand joints, it is most commonly seen in the knee joint (Neogi et al., 2012). Although the primary change in knee OA is in the articular cartilage of the knee, all tissues in and around the joint are affected by OA. The clinical features of the condition are pain, joint stiffness, edema, local tenderness in the joint, crepitation and swelling, muscle weaknesses, osteophytes, instability, subluxations, joint deformities, limitation of joint movement and functional limitations (Sharma 2021).

Pain in knee osteoarthritis is a multifactorial phenomenon in which structural, neurophysiological and psychosocial factors play a role (Emmert et al, 2018). Regarding neurophysiological factors, it has been shown that there are inflammatory mediators within the articular cartilage that alter afferent sensory inputs and cause plastic changes in the nervous system leading to central sensitization (Schaible et al, 2022). Although it is such a multifactorial symptom, the methods used in the evaluation of pain sensation for osteoarthritis are mostly subjective and include the patient's feedback, such as visual analog scale, numerical rating scale, Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) and Knee Injury and Osteoarthritis Outcome Score (KOOS). ) is limited to tests, surveys or scales (Dainese et al, 2022). Although these scales are an important part of clinical practice and reflect the patient's capacity to express his or her own experience, they provide subjective information on issues such as the patient's pain intensity, the effects of pain, and its effects on quality of life (Dainese et al, 2022).

Quantitative sensory testing (QST) is a systematic psychophysical testing method used to measure sensory thresholds for pain, touch, vibration and temperature sensations (Mücke et al, 2021). It measures individual sensory perceptions using direct patient feedback. It tests sensory loss (hypoesthesia, hypoalgesia) and sensory gain (hyperesthesia, hyperalgesia, allodynia) and is used to test the nociceptive and non-nociceptive properties of different afferent nerve fibers and central pathways (Mücke et al, 2021). Quantitative sensory testing may offer a more objective approach to identifying underlying causes of pain. Physical measurements such as nerve damage, loss of sensation, and changes in touch sensitivity can provide more objective data in assessing pain (Arant et al, 2021).

It has been reported that pain, movement limitations and muscle weakness in individuals with osteoarthritis cause indirect effects on muscle activity and functions (Petterson et al, 2023). Changes in muscle activity usually occur in response to pain or as the patient tries to compensate for functional limitations in the joint (Petterson et al, 2023).

It has been shown that due to pain and movement limitations in the affected joint, it causes the individual to change body position and use other muscle groups more (Sharma 2021). Avoidance of using the affected joint has also been reported as a factor in the weakening of the relevant muscle groups. OA can affect joint stability, which can impair muscle coordination (Sharma 2021). Superficial Electromyography (EMG) appears as a method that helps us monitor changes in the activation patterns of certain muscle groups and understand the underlying causes of these functional limitations (Simonsen et al., 2014).

OA treatment generally focuses on relieving symptoms, controlling pain, improving joint function, and improving quality of life (Block et al, 2020). Treatment methods used in the rehabilitation of patients with OA include exercise, electrotherapy and manual therapy. Mulligan Movement Mobilization (MWM), which is among manual therapy practices, is a manual therapy concept developed by Brian Mulligan. This concept includes a set of techniques aimed at correcting pain and limitations in joint range of motion (Anwer et al, 2018). It has been supported by studies that in conditions such as osteoarthritis, these mobilization techniques can help increase joint mobility and relieve the patient's symptoms (Alkhawajah et al, 2019).

The basic principles of Mulligan Movement Mobilization include collaboration with the patient, pain-free mobilization, and a manual force applied during a specific joint movement. It is aimed to increase joint range of motion, pain control and functional recovery, and to contribute to the patient being more effective in daily activities by increasing joint function (Oskay et al., 2015), (Alkhawajah et al., 2019).

Inclusion Criteria:

• Diagnosing knee OA according to the American College of Rheumatology (ACR) criteria (Primary knee OA diagnosis)
• Stage 2 or 3 patients according to Kellgren-Lawrence radiological staging criteria
• Patients with a disease duration of 6 months or longer
• Participants aged between 50 and 70
• Being able to walk without using assistive devices
• Body mass index is below 35 kg/m²
• Pain intensity must be between 3 and 7 according to the Numerical Pain Rating Scale
• Not having received physiotherapy in the last year.

Exclusion Criteria:

• Infiltration with steroids or local anesthetics in the year before the patient entered the study or during follow-up
• Obtaining the indication for surgery
• Severe hearing, vision and speech impairment
• Having serious systemic and cardiovascular diseases that prevent exercise
• Having a neurological disease
• Having a lower extremity deformity (severe varus or valgus deformity, significant joint instability and other orthopedic problems requiring surgical intervention)
• Patients with acute knee inflammation
• Having any disorder, syndrome or disease that may cause myofascial or neuropathic pain in the lower extremities, such as lumbar radiculopathy, meralgia paresthetica or Saphenous nerve compression.
• Cognitive deficit (Alzheimer's, dementia) revealed in the clinical history.

The research was designed as a double-blind randomized controlled study in which the participant and the evaluator were blinded.