1. Reporter: Chao-jung Hsieh Supervisor: Sai-wei Yang Date: 2007/10/29
Role of muscle strength affecting dynamic balance ability for subjects with knee osteoarthritis
Reporter: Chao-jung Hsieh
Supervisor: Sai-wei Yang
Date: 2007/10/29

2. Outline Introduction Materials and methods Knee osteoarthritis
Literature review
Materials and methods
Participants
Experimental procedure

3. Introduction
Knee 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

4. 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
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

5. Knee Osteoarthritis
71% ~ 91% of total joint load is transmitted through the medial compartment of knee joint
Maly 2002
The symptoms include:
Joint stiffness
Pain
Deterioration of coordination

6. Balance 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-bearing
Dynamic stability- functional tests
Niam 1999

7. Postural 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

8. Postural control 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

9. Muscle control Robbins 1989
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

10. Purpose and dynamic balance among subjects with knee OA
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

11. Materials and methods Participants Eligibility criteria
Thirty subjects with bilateral knee osteoarthritis, as
well as a group of thirty controls
Eligibility criteria
Age over 40 years old
No other disease of lower extremity
Exclusion criteria
Receiving any surgeries of lower extremity
Having severe medical illnesses that affected the
subject’s ability to perform sustained activities

12. Experimental procedure
Basic data measurements
Dynamic balance
Muscular strength
Knee pain

13. Basic data measurements
Descriptive data
Age
Gender
Height
Weight
Physical activity level
Health condition
Berg Balance Score (BBS)

14. Dynamic balance 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)

15. Dynamic balance Pitch Row Total travelled way Ellipse area
Center of pressure (CoP)
Total travelled way
Ellipse area
Maximal AP/ML distance
Ratio of weight bearing
Pitch Row

16. Muscular strength Isokinetic dynamometer Frontal plane Sagittal plane
Hip abduction/adduction
Ankle eversion/inversion
Sagittal plane
Knee flexion/extension
Ankle plantar-flexion/ dorsi-flexion
Electromyography

17. Muscular strength Peak torque Power Latency of muscle firing N-M Time
Whipple 1987; Toole 2000; Carmeli 2002
Hocherman 1984

18. Knee pain Visual analogue scale (VAS) Lequesne index
Western Ontario and McMaster Universities
Osteoarthritis Index (WOMAC)

19. Flow chart Statistical analysis Experimental procedure
Participants
Normal group
OA group
Data measurements
Descriptive data
Questionnaires
Experimental procedure
Dynamic balance
Muscle strength
Statistical analysis
Inform consent

20. Clinical application
Treatments – strengthening exercise

21. References
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:
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:
Kul-Panza E, Berker N(2006) Pedobarographic findings in patients with knee
osteoarthritis . Am J Phys Med Rehab,85:
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:

22. Thanks for your attention

23. Center of pressure Center of pressure (CoP)
Trajectory of body center of mass over the support
Movements of CoP are indicators of stability
Alexander 1994

24. Displacements of CoP Anterior/posterior direction
Ankle plantar/dorsi flexors
Medial/lateral direction
Hip abductors
Ankle evertors/invertors
Winter 1987