Role of muscle strength affecting Role of muscle strength affecting dynamic balance ability for dynamic balance ability for

subjects with knee osteoarthritis subjects with knee osteoarthritis

Reporter: Chao-jung HsiehSupervisor: Sai-wei Yang

Date: 2007/10/29

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OutlineOutline

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• Introduction Knee osteoarthritis Literature review

• Materials and methods Participants Experimental procedure

IntroductionIntroductionKnee osteoarthritis (OA) is one of major problems in the elderly

Knee OA, rather than any other joint, is more likely to cause disability Davis 1998

In Taiwan, the prevalence of OA ranges from 5.1% to 6.3% Chou et al 1994

It is defined as a degenerative condition that lead to joint symptoms and signs which is associated with defective integrity of articular cartilage, in addition to related changes in the underlying bone and at the joint margins

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Classification of osteoarthritis• The Kellgren-Lawrence scale

The severity of articular cartilage changes of OA by radiographs

Patellofemoral joint space narrowing

Presence of osteophytes

Kellgren-Lawrence Scale 0 No osteophytes

1 Doubtful osteophytes

2 Minimal osteophytes, possible narrowing, cysts, and sclerosis

3 Moderate or definite osteophytes with moderate joint space narrowing

4 Severe with large osteophytes and definite joint space narrowing

Knee OsteoarthritisKnee Osteoarthritis

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71% ~ 91% of total joint load is transmitted through the medial compartment of knee joint

Maly 2002

The symptoms include:Joint stiffnessPainDeterioration of coordination

BalanceBalance

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• Static balance• Dynamic balance

DeOreo 1980

• Evaluation / Training of dynamic balance is effective for improving the postural control ability

Shumway-Cook 2000

Steadiness- trajectory of center of pressure Symmetry- ratio of weight-bearingDynamic stability- functional tests

Niam 1999

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Postural controlPostural control• Difficulty in squatting, kneeling, and rising from a chair • Avoidance of pain associated with limb loading and decline in postural control ability Bennell 2003; Na 2003

Postural controlPostural control

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• Individuals with knee OA demonstrate Significantly more postural sway than the age-matched group Wegener 1997; Kul-Panza 2006 Balance deficits in clinical tests Hinman 2002

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Muscle controlMuscle control• Effective control of balance rely not only accurate sensory input but also a timely response of strong muscles• Subjects with knee OA revealed

Quadriceps are weak with delayed activation when walking

Birmingham 2001

The lower extremity muscular strength is reduced

Kaufman 2001

Increased hamstring muscle activation while executing activities of daily life Hortobagyi 2005

•Knee and hip weakness are related to poor balance and a

greater risk of falling

Robbins 1989

PurposePurpose

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• To investigate the relationship between muscle strength and dynamic balance among subjects with knee OA • To determine the role that severity of knee pain play in the ability to maintain balance

Materials and methodsMaterials and methods

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• ParticipantsThirty subjects with bilateral knee osteoarthritis, as well as a group of thirty controls

• Eligibility criteria Age over 40 years oldNo other disease of lower extremity

• Exclusion criteriaReceiving any surgeries of lower extremityHaving severe medical illnesses that affected the subject’s ability to perform sustained activities

Experimental procedureExperimental procedure

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• Basic data measurements• Dynamic balance• Muscular strength• Knee pain

Basic data measurementsBasic data measurements

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• Descriptive data AgeGender Height Weight Physical activity levelHealth condition

• Berg Balance Score (BBS)

Dynamic balanceDynamic balance

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• Dynamic perturbation system (Stewart platform) Sinusoidal angular rotation with 10°at 0.3Hz/0.6Hz Antonio 2000; Yang 2001

• The footscan system (Rsscan International Co., Belgium)

Dynamic balanceDynamic balance

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• Center of pressure (CoP)Total travelled wayEllipse areaMaximal AP/ML distanceRatio of weight bearing

Pitch Row

Muscular strengthMuscular strength

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• Isokinetic dynamometer• Frontal plane

Hip abduction/adductionAnkle eversion/inversion

• Sagittal planeKnee flexion/extensionAnkle plantar-flexion/ dorsi-flexion

• Electromyography

Muscular strengthMuscular strength

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• Peak torque• Power

• Latency of muscle firingWhipple 1987; Toole 2000; Carmeli 2002

N-M

Time

Hocherman 1984

Knee painKnee pain

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• Visual analogue scale (VAS) • Lequesne index • Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC)

Flow chartFlow chart

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Inform consentInform consent

Clinical applicationClinical application

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• Treatments – strengthening exercise

ReferencesReferences

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• Whipple RH, Wolfson LI, Amerman PM(1987)The relationship of knee and ankle weakness to falls in nursing home residents: An isokinetic study. JAGS. 35:13-20• Wegener L, Carolyn K, Nichols D(1997)Static and dynamic balance responses in persons with bilateral knee osteoarthritis. JOSPT. 25:13-18• Jadelis K, Miller ME, Ettinger WH and Messier SP(2001)Strength, balance, and the modifying of obesity and knee pain. J Am Geriatr Soc. 49:884-891• Yelin EH, Felts WR. (1990) A summary of the impact of musculoskeletal conditions in the United States. Arthritis Rheum, 33:750-5• Birmingham TB, Kramer JF, Kirkley A, et al.(2001)Knee brace for medial compartment osteoarthritis: effect on proprioception and postural control. Rheumatology, 40:285-289• Kul-Panza E, Berker N(2006) Pedobarographic findings in patients with knee osteoarthritis . Am J Phys Med Rehab,85:228-233• Jadelis K, Miller ME, Ettinger WH, et al.(2001) Strength, balance and the modifying effects of obesity and knee pain: results from the Observational Arthritis Study in Seniors (OASIS). J Am Geriatr Soc,49:884-891

Thanks for your attentionThanks for your attention

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Center of pressureCenter of pressure

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• Center of pressure (CoP)Trajectory of body center of mass over the supportMovements of CoP are indicators of stability

Alexander 1994

Displacements of CoPDisplacements of CoP

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• Anterior/posterior direction Ankle plantar/dorsi flexors

• Medial/lateral direction Hip abductors Ankle evertors/invertors Winter 1987