The Relationship of the Medial Longitudinal Arch Height With Clinical Features of Knee Osteoarthritis

Study Overview
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Brief Summary
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The goal of this observational study is to investigate the relationships between the medial longitudinal arch (MLA) height of the foot and clinical and radiological characteristics of knee osteoarthritis in adult patients 50 aged and over. The main questions it aims to answer are: Is there any relationship between knee pain and disability in knee osteoarthritis and MLA height? Is there any relationship between the radiologic severity of knee osteoarthritis and MLA height? Is there any relationship between knee joint alignment in knee osteoarthritis and MLA height?

Detailed Description
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Differences in hind and midfoot structures, including the medial longitudinal arch, affect lower limb alignment and biomechanics. However, the causal relationship between knee joint problems and foot deformities is controversial. Knee osteoarthritis, a common orthopaedic condition in the elderly population, tends to distort the lower limb alignment by narrowing the tibiofemoral joint space asymmetrically. Therefore, knee varus and medial longitudinal arch deformities may change gait biomechanics on knee osteoarthritis. However, there is insufficient evidence on the relationship between variation in foot posture and disease severity, knee varus deformity, knee pain and disability in knee osteoarthritis. In this study, investigators will examine the lower extremity alignment and osteoarthritis severity in terms of MLA height in adults with knee osteoarthritis. The study sample will be formed by the simple random sampling method from adult patients with knee osteoarthritis who will be admitted to our clinics and outpatient clinics with knee pain. It was planned to include 93 participants to be able to detect the two-way correlation between the knee WOMAC score and the arch height index with an effect size of 0.3, a power of 90%, and a 5% margin of error. Initially, demographic data, including age, gender, body mass index (BMI), limb dominance, and time from knee pain onset of participants, will be recorded. For both knees goniometric measurement of knee passive range of motion (ROM), visual analogue scale (VAS) for pain and Western Ontario and McMaster Universities Arthritis Index (WOMAC) will be applied. Kellgren/Lawrence stages, mechanical, and anatomical tibiofemoral angles for knee joints will be obtained from lower limb length X-ray. MLA height index measurement will be performed by an investigator blinded to the patient's clinical condition. According to the results of descriptive statistics, the relationship between MLA height measurement results (arch height index and arch height flexibility) and Kellgren-Lawrence stage, VAS, WOMAC and tibiofemoral angles will be examined by correlation analysis. In case of significant correlation, regression analyses for Kellgren-Lawrence, VAS and WOMAC scores as dependent variables will be applied.

Official Title
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The Relationship of Medial Longitudinal Arch Height With Pain, Disease Severity and Knee Joint Alignment in Patients With Knee Osteoarthritis

Conditions
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Foot Deformities, Pes Planus, Pes Cavus, Knee Osteoarthritis, Knee Pain Chronic, Disability Physical, Lower Limb Deformity

Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Being 50 years old or older Having a diagnosis of knee osteoarthritis according to the American College of Rheumatology Exclusion Criteria: History of fracture or orthopaedic surgery involving lower limbs Presence of neurological condition resulting in lower limb sensorimotor deficit Having another inflammatory rheumatological disease Having a malignant tumour with bone metastasis Having lower limb oedema, lymphedema, skin and soft tissue loss that will prevent the evaluation of foot morphology (arch height index) Severe neuropsychiatric disease or condition that interferes with communication Having therapeutic injection into the knee joint in the last 3 months Presence of any major trauma that aggravated knee pain in the last 6 weeks

Ages Eligible for Study
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Minimum Age: 50 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Patients with knee osteoarthritis<br>Adult patients 50 years of age or older diagnosed with knee osteoarthritis according to American College of Rheumatology criteria | |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Arch Height Index while bipedal standing | The ratio of the dorsum height of the foot (measured in the middle of the total foot length) to truncated foot length, while bipedal standing. Normal values have been reported to be approximately 0.338 ± 0.031 to 0.343 ± 0.033 in college-aged women. Higher values represent the increased medial longitudinal arch height of the foot (e.g. pes cavus) while lower values are related to pes planus. | Within the three days of clinical evaluation | 
| Arch Height Index while sitting | The ratio of the dorsum height of the foot (measured in the middle of the total foot length) to truncated foot length, while sitting with feet calmly on the ground. Normal values have been reported to be approximately 0.355 ± 0.031 to 0.369 ± 0.034 in college-aged women. Higher values represent the increased medial longitudinal arch height of the foot (e.g. pes cavus) while lower values are related to pes planus. | Within the three days of clinical evaluation | 
| Arch Height Flexibility | Arch Height Flexibility will be calculated by the [(arch height while sitting - arch height while standing) / 0.4 x body weight] x 100 (m/kN) formula. Higher values represent the more flexible medial longitudinal arch structure. | Within the three days of clinical evaluation | 
| Kellgren Lawrence stage of knee osteoarthritis | It is a radiological grading of knee osteoarthritis with a value between 0 to 4. Medial and lateral tibiofemoral compartments are evaluated on weight-bearing anteroposterior knee radiograph in terms of joint space narrowing, subchondral periosteal sclerosis, subchondral cyst and osteophytic formations. Zero means no radiographic evidence of osteoarthritis, while 4 indicates advanced knee osteoarthritis. | Within the three days of clinical evaluation | 
| Anatomical tibiofemoral angle | It is the angle, measured on a weight-bearing, full-length anteroposterior lower limb radiograph, between the anatomical axes of the femur and tibia. The normal value of the anatomical tibiofemoral angle is between 4 to 6 degrees of valgus. A higher positive value will indicate more valgus posture of the knee, while lower or negative values will be related to varus deformity. | Within the three days of clinical evaluation | 
| Mechanical tibiofemoral angle | It is the angle, measured on a weight-bearing, full-length anteroposterior lower limb radiograph, between the lines drawn from the femoral head to the femoral intercondylar notch and from the tibial interspinous point to the tibial mid-plafond. The mechanical tibiofemoral angle is approximately 1-1.5 degrees of varus for a knee in normal alignment. In this study, to ensure consistency with the anatomical tibiofemoral angle values, the direction of angulation will be noted as a positive or negative value for the valgus or varus, respectively. | Within the three days of clinical evaluation | 
| Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) scores for both knees | WOMAC is a specific, valid and reliable tool for measuring disability in the knee and hip osteoarthritis. It includes 24 questions under three sub-domains: pain, stiffness, and physical function. Each question is scored on a Likert scale as 0=none, 1=mild, 2=moderate, 3=severe, and 4=extreme. The total score is defined by the [(sum of the scores)/96]x100 formula and ranges from 0 to 100. Higher scores indicate increased disability due to more severe pain, stiffness and impaired physical function. | Within the three days of clinical evaluation | 
| Visual analogous scale score for knee pain | Participants are asked to mark the severity of their right and left knee pain in the past month on a 100 mm horizontal line; where point zero represents no pain and point 100 represents the most severe pain possible. The result is noted in millimetres by measuring the distance from the zero to the marked point. Increasing values represent higher pain intensity. | Within the three days of clinical evaluation | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Knee range of motions | Flexion and extension range of motions will be measured using a goniometer regarding the neutral zero method for both knees. Decreased values represent a limited range of motion of the knee joint. | Within the day of clinical evaluation | 
| Time after pain onset (weeks) | The duration of knee pain leading to hospital admission will be noted. | Within the day of clinical evaluation | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Medial longitudinal arch, Arch height index, Knee osteoarthritis, Knee pain, Foot, Lower limb alignment