Elasticity of the Hoffa's Fat Pad in Patients With Knee Osteoarthritis

Study Overview
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Brief Summary
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Knee osteoarthritis (OA) is a common problem in clinical settings. Knee OA is well known for its association with the wear and tear of the cartilage and osteophyte formation. Evidence has suggested the importance of the infrapatellar fat pad, known as Hoffa's fat pad, during the development of knee OA. Some studies have demonstrated the protective role of the infrapatellar fat pad, whereas others have suggested an inflammatory role such as increased fibrosis and proinflammatory cytokine levels. Ultrasound is exceptionally convenient in the assessment of the musculoskeletal system, and elastography is a tool to evaluate tissue texture. Therefore, in this study, we investigated the Hoffa's fat pad in knee OA patients by using elastography.

Detailed Description
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This was an observation study that included a control group. We enrolled 20 patients with knee OA, as well as 10 healthy individuals. The Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) and Kellgren-Lawrence X-ray grading were employed to determine disease severity. All the study participants received elastography assessment, including strain and shear wave elastography in the knee extension and flexion position. The strain elastography contained color mapping that enabled the calculation of the relative texture and strain ratio. The shear wave elastography revealed the qualitative velocity, which was measured 3 times. Each patients with knee OA received elastography examination twice: once before hyaluronic acid injection and once 1 month after the injection.

Official Title
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Elasticity of the Hoffa's Fat Pad in Patients With Knee Osteoarthritis

Conditions
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Knee Osteoarthritis, Elasticity Imaging Techniques

Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: OA group Kellgren-Lawrence grading I-IV proved by knee X-ray Healthy group No knee pain or received injection during the past 1 year No history of knee OA Exclusion Criteria: History of knee surgery, trauma or malignancy History of patellar tendinopathy or patellofemoral pain syndrome Refused informed consent

Ages Eligible for Study
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Minimum Age: 20 Years
Maximum Age: 86 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| knee osteoarthritis group<br>individuals being diagnosed with osteoarthritis and classified by K-L grading | |
| healthy group<br>individuals without knee pain or diagnosis of knee osteoarthritis | |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| shear modulus | the absolute quantitative measurement of elasticity (kPa) of Hoffa's fat pad | before and 1-3 months after hyaluronic acid injection | 
| strain ratio | the semiquantitative measurement of elasticity of Hoffa's fat pad, a ratio with patellar tendon as reference | before and 1-3 months after hyaluronic acid injection | 
| thickness of Hoffa's fat pad | the thickness of Hoffa's fat pad from mid patellar tendon to femur cartilage | before and 1-3 months after hyaluronic acid injection |