INTRODUCTION: dynamic stabilizer of the knee joint since
Osteoarthritis is the most common chronic joint disease which occurs due to breakdown of joint cartilage and underlying bone. 1 Primary knee osteoarthritis is a major cause of impairment of mobility of the lower limb. There is no known cure for this progressive and degenerative disease, making effective rehabilitation particularly important. 2Apart from pre-established factors involved in osteoarthritis, like age, gender, body weight, height, activity level, the strength of quadriceps muscle has also been shown to influence pain and disability of the lower limbs.
The major clinical symptom of knee osteoarthritis is knee pain. 3Symptomatic knee osteoarthritis, defined as a Kellgren-Lawrence grade of at least mild radiographic osteoarthritis and symptoms in the same knee, is significant in both clinical diagnoses as well as in measuring the public health burden. 4 Quadriceps muscle weakness may also contribute to knee pain. 5
The quadriceps femoris muscle is the principal dynamic stabilizer of the knee joint since it offers ample shock absorption for the knee during gait, due to its eccentric contraction. 6 Quadriceps weakness is one of the initial clinical findings among persons with knee osteoarthritis 7-10 which appears even before patient-reported symptoms, and may play a vital role in disease advancement. 11, 12 Quadriceps strength has been found to be reduced in patients with higher grades of osteoarthritis. 13Inadequate attenuation of large compressive forces at the knee can result in precipitate loading, which has been credited to quadriceps weakness and inactivity. 14 Quadriceps weakness could, thus, predispose the knee joint to injury and cause further deterioration of the existing injury. 2
This study is a step towards analyzing the unique link that quadriceps weakness forms with symptomatic and radiographic knee osteoarthritis, especially in the chosen population of the hilly region of Sullia, Dakshina Karnataka. Progressive diminution of quadriceps strength with increase in radiological and symptomatic grades of osteoarthritis may substantiate the concept of increasing the strength of quadriceps muscle to halt the progression of the disease or at least, reduce the pain and disability associated with this severely debilitating disease.
1. To determine the isometric quadriceps strength in patients with symptomatic osteoarthritis of the knee
2. To compare the isometric quadriceps strength in patients with mild, moderate and severe radiological knee osteoarthritis
3. To identify the association of quadriceps strength with pain and disability in patients with knee osteoarthritis.
Study design: This study will be a cross-sectional type of study.
Sampling technique: Convenient sampling method will be followed.
Study population: In the duration of two months, patients visiting Orthopedics Outpatient Department with complaints of pain in knee joint and fulfilling the inclusion criteria will be taken in for this study, till the goal of 50 subjects is reached.
The study population will be divided into two categories which are further divided into three groups each:
Kellgren-Lawrence grading (radiographic osteoarthritis)
Western Ontario McMaster Universities Osteoarthritis Index scoring for pain and disability (symptomatic osteoarthritis)
1. Mild osteoarthritis (K/L Grade I),
1. Mild pain and disability,
2. Moderate osteoarthritis (K/L Grade II)
2. Moderate pain and disability
3. Severe osteoarthritis (K/L Grades III and IV)
3. Severe pain and disability
1. Subjects aged above 40 years
2. Patients reporting pain in knee joint, which is insidious in onset and lasting for a duration more than 1 month
3. Patients with knee radiographs in standing position, showing features of osteoarthritis as per Kellgren-Lawrence (K/L) grade more than or equal to K/L grade I.
1. Those who are not willing to participate in the study and/or are not willing to give the required consent form.
2. Patients with history of recent or old trauma to the same painful knee, directly or indirectly causing severe bony or ligament injuries, which has been documented in their previous medical records
3. Patients with pain in multiple joints, indicating inflammatory origin of arthritis like rheumatoid arthritis, ankylosingspondylitis, etc.
4. Patients with history of previous surgeries on the same painful knee or history of infection, indicating septic arthritis
Informed consent will be taken from the subjects through a consent form. Confidentiality will be maintained. The subject’s choice to participate in the study will not be influenced under any circumstances. The methodology will be followed in accordance with the institutional ethical standards.
1. Western Ontario McMaster Universities Osteoarthritis Index (WOMAC) scoring for assessment of knee pain
2. Radiographic evaluation using Kellgren-Lawrence grading
3. Assessment of isometric quadriceps muscle strength by modified Hand Held Dynamometer
Ø Assessment of Knee Pain-
ü All patients included, will be subjected to the questionnaire as per Western Ontario McMaster Universities Osteoarthritis Index scoring scale for categorizing their pain.
ü As per the scoring, patients will be sub-grouped into those with Mild pain and disability, Moderate pain and disability, and Severe pain and disability. 5
Ø Radiographic evaluation-
ü Radiographic evaluations consist of anteroposterior radiograph of the patient’s knee in the standing position. The Kellgren and Lawrence scale of OA grading will be used.
ü The patients will be sub- grouped as per Kellgren-Lawrence grading system into those with Mild osteoarthritis (K/L Grade I), Moderate osteoarthritis (K/L Grade II), Severe osteoarthritis (K/L Grades III and IV). 5
ü Radiographs will be reported by an academically based bone and joint radiologist.
Ø Assessment of Quadriceps Muscle Strength-
ü Muscle strength is the force generated by a contracting muscle. The hand-held dynamometer is an objective instrument designed to measure isometric quadriceps strength during its contracture.
ü The hand-held dynamometer has been modified with straps tied onto the affected leg over the ankle to provide support during testing.
ü The patients will be instructed about the procedure and guided to sit on a fixed chair with their hips and knees flexed to 90o.
ü They will place both hands on the distal parts of their thighs to avoid compensation.
ü The patients will be instructed to extend the leg against the resistance offered by the dynamometer, leading to the contraction of the quadriceps muscle in an isometric manner.
ü The reading from the dynamometer is documented and this is a measure of the quadriceps muscle strength.
ü Each patient will perform 3 trials, with resting time of about 5 minutes between each trial and the maximum reading of strength amongst the 3 trials are taken as the final reading. 15
The subjects will complete assessments for pain and functioning, strength, and radiographic examinations on the same day.
The data will be entered in Microsoft Office Excel 2007 and analysis will be done using IBM SPSS version-17. The comparision of the quadriceps strength in patients will be done using unpaired student t-test.
By determining the quadriceps strength at an early and late stage of osteoarthritis in reference to the levels of pain, this study intends to show the influence of quadriceps strength in the progress of the disease pattern.
Failing to address strength deficits may hold serious complications which include further joint deterioration and continued functional decline. These deficits may persist following surgical intervention and restrict functional recovery. 16
Physical activity programs can lessen pain, enhance overall physical performance, reduce depressive symptoms, and prevent or postpone disability in knee osteoarthritis. 17 Rehabilitation therapists can introduce strengthening interventions at an appropriate stage to circumvent the devastating symptoms of this disease.