Research Review By Dr. Ceara Higgins©

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Date Posted:

August 2016

Study Title:

Clinical Tests of Standing Balance in the Knee Osteoarthritis Population: Systematic Review and Meta-analysis

Authors:

Hatfield GL, Morrison A, Wenman M, et al.

Author's Affiliations:

Department of Physical Therapy, University of British Columbia, Canada.

Publication Information:

Physical Therapy 2016; 96(3): 325–337.

Background Information:

Knee osteoarthritis (OA) can affect the entire synovial joint, with changes seen in the articular cartilage, subchondral bone, ligaments, periarticular muscles, nerves, and menisci (1). These changes lead to pain, stiffness, deficits in muscle strength, joint instability and difficulty with activities of daily living. This is especially problematic for individuals over 65 years of age (2). Specifically, it has shown that close to 50% of individuals with severe OA could be expected to fall within a year (3). Balance is a critical part of healthy aging that relies (at least partially) on knee integrity, which can be affected by muscular strength, radiographic OA severity, knee alignment, pain, and proprioception. Assessment of balance for individuals with knee OA in a clinical setting can be useful, but this construct needs to be assessed with tools that are relatively simple, inexpensive, and easy to administer. This study aimed to analyze the available data on the most common clinical tests used to determine balance in those with knee OA a clinical setting.

Pertinent Results:

8 studies met the inclusion criteria and were included in this review. The evidence pertaining to individual tests will be discussed below.

Community Balance and Mobility Scale:
This test consists of 13 tasks, which include bending, turning, or looking while walking, single-leg stance, and stair descent. The test is scored out of 96, with each task scored from 0 (unable to perform) to 5 (proficient), with the exception of stair descent, which is scored out of 6. In a single study comparing individuals with knee OA to healthy controls (5), those with knee OA scored 71/96 compared to 85/96 in healthy individuals.

Berg Balance Scale:
This test consists of 14 tasks testing static and dynamic balance with each test receiving a score from 0 (unable to perform or needs assistance) to 4 (able to perform independently), with a maximum score of 56. Two studies (5, 6) compared participants with knee OA to healthy controls and showed performance ranging from 50-56 in individuals with knee OA and 53-56 in healthy individuals.

Functional Reach Test:
Participants stand with their feet 10 cm apart next to a measuring stick mounted on the wall. Making a fist with their dominant hand, they then raise the hand so the arm is parallel to the floor and reach the arm forward as far as possible without taking a step or touching the wall. One study compared individuals with knee OA to healthy controls (6), with individuals with knee OA reaching 23 cm versus 29 cm in healthy controls; while a second study compared individuals with unilateral knee OA to those with bilateral knee OA (7), and found no significant differences.

Single-Leg Stance Test:
Participants perform unilateral stance on the test leg while keeping the other leg from touching the ground and keeping the trunk as still as possible. Two or three attempts with eyes open are performed and timed, with the maximum time recorded. In two studies of individuals with knee OA compared to healthy individuals (5, 6), those with knee OA showed significantly worse results, with times ranging from 24-42 seconds versus 50-66 seconds in the healthy controls.

Step Test:
Participants balance on the study limb while stepping on and off of a 15-cm step with the contralateral foot as many times as they can within 15 seconds. Two studies compared individuals with knee OA to healthy controls (8, 9) and two studies compared groups with knee OA causing different varus alignments (10, 11). Participants with knee OA showed performances ranging from 12-14 steps, while healthy controls were able to complete 5 more steps in the 15 second time period.

Tandem Stance Test:
Participants stand with their feet side by side, first semi-tandem and then tandem for 10 seconds each. The test is scored as 0 (able to maintain semi-tandem stance to < 10 seconds), 1 (able to maintain tandem stance for < 2 seconds), 2 (able to maintain tandem stance for 3-9 seconds), or 3 (able to maintain tandem for a full 10 seconds). In a single study of individuals with knee OA versus healthy controls (12), those with knee OA showed only 11% of men and 17% of women with the ability to maintain tandem stance for 10 seconds, while healthy controls showed 31% of men and 39% of women with the same ability.

When results of the studies were pooled it was found that individuals with knee OA had significantly poorer balance than healthy controls. It was difficult to determine the similarity of the groups due to significant differences in knee OA severity and the variety of standing tests used. No studies comparing balance between groups with different radiographic severities of knee OA were found.

Clinical Application & Conclusions:

The largest differences in balance between knee OA populations and healthy controls were seen with the Step Test, the Functional Reach Test, and the Community Balance and Mobility Scale. These have all been found to be reliable tests in the knee OA population and should be considered for clinical use.

Study Methods:

Two reviewers checked the abstracts of all articles found and pulled full-text articles for those fitting the inclusion criteria below. The reference lists of all included articles were also hand searched and once the most common clinical tests of standing balance were identified, the literature was also searched for those tests. Two other independent reviewers then assessed and extracted the data from the articles. A modified version of a validated quality index for nonrandomized trials was used to assess methodological quality of studies (those scoring less than 50% were excluded from the review). A third assessor was consulted in any case where there was disagreement.

Inclusion Criteria:
  • Human-based studies examining clinical tests of standing balance in individuals with radiographically diagnosed knee OA.
  • Clinical tests of balance must quantify one or more aspects of standing balance and not require any specialized equipment that is not commonly available at most physical therapy (or chiropractic) clinics.
  • Testing must provide a numeric estimate of performance.
Exclusion Criteria:
  • Studies using nonclinical measures of standing balance.
  • Studies containing participants with radiographically identified OA in weight-bearing joints other than the knee.
  • Studies containing participants who had undergone total joint arthroplasty in the study limb.
  • Studies containing participants requiring the use of a walking aid
  • Studies without a comparison group.
  • Review articles.
  • Articles not available in English.
In studies including an intervention, only the pre-intervention test scores were included for this study. In cases where studies reported on more than one clinical test, the data from only the highest-ranking test on the following list was extracted.
  1. Community Balance and Mobility Scale
  2. Berg Balance Scale
  3. Functional Reach Test
  4. Single-Leg Stance Test
  5. Step Test
  6. Tandem Stance Test
The first two tests were given precedence because they are multi-task balance tests that challenge a variety of standing balance abilities, with the Berg Balance Scale being ranked slightly lower due to an established ceiling effect (5). The third and fourth tests (Functional Reach and Single-Leg Stance) were next as they have established reliability in the knee OA population (5) and the ability to predict falls in older adults. Finally, the fifth and sixth tests (Step and Tandem Stance) were ranked last as they do not have established reliability and validity in the knee OA population, with the Step Test being ranked higher, as it has been shown to be reliable in healthy adults after a stroke.

Study Strengths / Weaknesses:

Strengths:
  • When multiple studies by the same author were found that fit the inclusion criteria, participant characteristics were checked to ensure duplicate data was not included.
Weaknesses:
  • Other factors associated with defects in balance, such as quadriceps muscle strength, knee alignment, pain severity, and proprioceptive activity (4) were not considered by many of the included studies.
  • Although the Step test was commonly used in the literature (4 studies) and shown to be a sensitive enough test for detecting and monitoring deficits in standing balance, three of the studies were by the same research group, so it is unclear if the test is actually in widespread clinical use.
  • Many of the tests used in the literature are single-task tests which, while easy to administer, may be of limited value in assessing balance, which is a multidimensional task.

Additional References:

  1. Brandt KD, Radin EL, Dieppe PA, et al. Yet more evidence the osteoarthritis is not a cartilage disease. Ann Rheum Dis 2006; 65: 1261-1264.
  2. Hunter DJ, Felson DT. Osteoarthritis. BMJ 2006; 332: 639-642.
  3. Levinger P, Menz HB, Wee E, et al. Physiological risk factors for falls in people with knee osteoarthritis before and early after knee replacement surgery. Knee Surg Sports Traumatol Arthrosc 2011; 19: 1082-1089.
  4. Hunt MA, McManus FJ, Kinman RS, et al. Predictors of single-leg standing balance in individuals with medial knee osteoarthritis. Arthritis Care Res 2010; 62: 496-500.
  5. Takacs J, Garland SJ, Carpenter MG, et al. Validity and reliability of the Community Balance and Mobility Scale in individuals with knee osteoarthritis. Phys Ther 2014; 94: 866-874.
  6. Sun S, Hsu C, Hwang C, et al. Hyaluronate improves pain, physical function and balance in the geriatric osteoarthritic knee: a 6-month follow-up study using clinical tests. Osteoarthritis Cartilage 2006; 14: 696-701.
  7. Adegoke BO, Babatunde FO, Oyeyemi AL. Pain, balance, self-reported function and physical function in individuals with knee osteoarthritis. Physiother Theory Pract 2012; 28: 32-40.
  8. Hinman RS, Bennell KL, Metcalf, et al. Balance impairments in individuals with symptomatic knee osteoarthritis: a comparison with matched controls using clinical tests. Rheumatology 2002; 41: 1388-1394.
  9. Mohammadi F, Taghizadeh S, Ghaffarinejad F, et al. Proprioception, dynamic balance and maximal quadriceps strength in females with knee osteoarthritis and normal control subjects. Int J Rheum Dis 2008; 11: 39-44.
  10. Lim BW, Hinman RS, Wrigley TV, et al. Varus malalignment and its association with impairments and functional limitations in medial knee osteoarthritis. Arthritis Rheum 2008; 59: 935-942.
  11. Lim BW, Hinman RS, Wrigley TV, et al. Does knee malalignment mediate the effects of quadriceps strengthening in knee adduction moment, pain, and function in medial knee osteoarthritis? A randomized controlled trial. Arthritis Rheum 2008; 59: 943-951.
  12. Kim I, Kim H, Seo Y, et al. Tibiofemoral osteoarthritis affects quality of life and function in elderly Koreans, with women more adversely affected than men. BMC Musculoskelet Disord 2010; 11: 129.