Associations among knee muscle strength, structural damage, and pain and mobility in individuals with osteoarthritis and symptomatic meniscal tear

Clinical Research 8 min 9

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Created On: 29/01/2020

Associations among knee muscle strength, structural damage, and pain and mobility in individuals with osteoarthritis and symptomatic meniscal tear

Knee osteoarthritis is significantly associated with functional disability and difficulty in performing daily activities.

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Key take away

Increasing quadriceps and hamstrings muscle strength can be helpful in reducing pain and improving mobility in patients with symptomatic meniscal tear and knee osteoarthritis.

Background

Knee osteoarthritis is significantly associated with functional disability and difficulty in performing daily activities. Functional disability or limitation can be defined as decrease in both objectively quantified mobility and self-reported difficulty performing daily life activities. Adopting an efficient therapeutic regimen that effectively reduces functional disability might be helpful in reducing pain and improving mobility in patients with knee osteoarthritis.

An individual also requires sufficient lower extremity muscle strength to perform the daily functional tasks. Studies suggest that patients with knee osteoarthritis symptoms also demonstrate deficits in hamstrings strength and quadriceps. Lower hamstring strength and quadriceps also leads to a variety of clinical features such as poor patient reported function, a decrease in physical performance and disease progression. Understanding the relationship between quadriceps and hamstrings strength and broad set of clinical features could help in determining efficacious treatment targets.

Research conducted in previous years had shown positive correlation between quadriceps and hamstrings muscle strength and clinical features. But the association had been found only in basis of instrumentation such as using an isokinetic dynamometer and hand-held dynamometer only. Hand-held dynamometers show excellent inter-session reliability but their applicability in clinical settings is still lacking. Therefore, the present study evaluates the relationship between the strength of the quadriceps and hamstrings measured with a hand-held dynamometer.

Rationale behind research:

There is a lack of literature demonstrating an association between muscle strength and physical function in patients with knee osteoarthritis using a hand-held dynamometer
Therefore, the present study was conducted to assess the relationships among quadriceps and hamstrings strength and structural damage in individuals with symptomatic meniscal tear and osteoarthritis

Objective:

To evaluate the associations among quadriceps and hamstrings strength measured with a hand-held dynamometer and 1) structural damage 2) patient-reported pain, and 3) performance of mobility tasks in individuals with symptomatic meniscal tear and osteoarthritis.

Method

Study outcomes:

The study outcomes included evaluation of:

Quadriceps and hamstrings strength using a hand-held dynamometer
Association of muscle strength with structural damage, mobility and patient reported pain and functional status. Structural damage, mobility and patient reported pain and functional status were assessed using radiographic K-L grade, Timed Up and Go (TUG) test and Knee injury and Osteoarthritis Outcomes Score (KOOS) respectively.

Time period: NA

Result

Outcomes:

The patients in the strongest quartile scored 14 and 13 points higher on the KOOS pain scale and ADL subscales for quadriceps strength (Fig 2,3)
The patients in the strongest quartile scored 13 and 14 points higher on the KOOS pain and ADL subscales for hamstrings strength (Fig 2,3)
Both the groups completed the TUG two seconds faster than subjects in the weakest quartile (Fig 4)

Discussion

This cross-sectional study observed that quadriceps and hamstrings strength were inversely proportional to the patient-reported pain and in completing activities of daily living, and structural damage. The individuals in the strongest quartiles reported less pain, less difficulty in performing daily activities and increased mobility. The differences between the strongest and weakest quartiles of quadriceps and hamstring strength related to pain and difficulty performing activities of daily life exceeded the minimal clinical difference (8 points) for the KOOS.

The study suggested that increasing muscle strength might be beneficial for reducing pain and difficulty performing daily life activities and improving modility in patients with symptomatic meniscal tear and knee osteoarthritis, however the results of the present study needs to be confirmed in longitudinal studies and trials.

Limitations

The study was not able to address the causal relationship between quadriceps and hamstrings muscle strength and clinical features of knee osteoarthritis
The effect of other lower extremity muscles, including the gluteus medius and gluteus maximus on KOOS scores and time to complete the TUG was not assessed

Clinical take-away

Quadriceps and hamstring muscle strength should be a key component for the non-operative management of symptomatic meniscal tear and knee osteoarthritis.