Description #
This unit will describe the correct administration, scoring and interpretation of the Single Leg Stance (SLS) test performed for TJA patients.
Learning Objectives #
By the end of this unit, the learner will be able to perform the following tasks for TJA patients:
– Administer the Single Leg Stance (SLS) test
– Score the Single Leg Stance (SLS) test
– Interpret the Single Leg Stance (SLS) test
What is this test? #
What is the Single Leg Stance Test? #
The Single Leg Stance (SLS) Test is a reliable3 measure that is useful for assessing THA and TKA patients and falls within the WHO’s ICF domain of Body Function/Structure6 (Figure 1). The SLS Test measures static balance while standing on a single leg with eyes open and closed2. In addition, it can be completed relatively quickly requiring approximately 5 minutes to administer and score.
Figure 1. The International Classification of Functioning, Disability and Health (ICF) Conceptual Model. Taken from Riddle, D. & Stradford, P. (2013). Is this Change Real? Interpreting Patient Outcomes in Physical Therapy. Figure 2-17.
When do I use the Single Leg Stance Test? #
The Single Leg Stance (SLS) Test can be used in a number of phases along the TJA Continuum of Care. Specifically, as seen in Figure 2, the SLS Test is recommended for use in the Pre-Operative, Post-Acute, and Active Living phases. Health professionals can therefore use this outcome measure to monitor change in the patient’s status as he or she moves through these phases of care (*note that it is not recommended in the Acute Phase).
Figure 2. The phases along the TJA Continuum of Care for which the SLS is recommended.
Equipment needed #
What equipment is used to perform the Single Leg Stance Test? #
To perform the Single Leg Stance (SLS) Test with a patient, only one piece of equipment is required:
- A stop watch
How do I do it? #
How do I administer the Single Leg Stance Test? #
- A written version of the instructions can be found at the following link → Single Leg Stance Test Instructions
How do I score it? #
How do I score the Single Leg Stance Test? #
Scoring the Single Leg Stance (SLS) Test is easy to do:
- Record the best time to the 10th of a second for both eyes open and eyes closed components of the SLS test2.
Example #
Ms. W had a left TKA four weeks ago and she has come into your clinic for treatment. You would like to assess Ms. W’s static balance so you decide to use the Single Leg Stance (SLS) Test as your performance based outcome measure. From your assessment, you find the following results:
Right Leg, Eyes Open:
– Trial 1 – 22 seconds
– Trial 2 – 21 seconds
Right Leg, Eyes Closed:
– Trial 1 – 16 seconds
– Trial 2 – 18 seconds
Left Leg, Eyes Open:
– Trial 1 – 6 seconds
– Trial 2 – 4 seconds
Left Leg, Eyes Closed:
– Did not attempt
What is Ms. W’s correct SLS Test scores?
The correct SLS Test scores for Ms. W are:
- Right Leg, Eyes Open: 22 seconds
- Right Leg, Eyes Closed: 18 seconds
- Left Leg, Eyes Open: 4 seconds
- Left Leg, Eyes Closed: Did not attempt as Ms. W’s score was less than 10 seconds for the left leg eyes open trial.
What does it mean? #
How do I interpret the Single Leg Stance Test? #
It is simple to interpret the Single Leg Stance (SLS) Test: the greater the number of seconds a patient can stand on one foot for both testing conditions (eyes open & eyes closed), the better their balance and the less risk they have of falling. For example,
- Adults unable to balance on 1 limb for 5 seconds had a 2.1 times the risk of having an injurious fall than those who could balance for >5 seconds5.
- The SLS test is indicative of falls risk during ADLs requiring single leg stance, such as stepping into a tub or getting dressed3.
Additional Information!
- While the MDC has not been established specifically for the OA or TJA population, it has been established for lower functioning community-dwelling older females (SLS <20 seconds). In this population the MDC95 = 8.3-11.6 secs can be used as an estimate when assessing the OA and TJA population4.
- Normative values for healthy adults ages 18-80+ are available at Rehab Measures 2,3.
Examples #
Ms. S is an 60 year female who is awaiting a TKA. She has come to your PT clinic to improve her strength and balance prior to surgery. On initial assessment, Ms. S’s SLS Test score was 3 seconds. After 4 weeks of treatment, Ms. SLS Test score improved to 10 seconds.
Has true change occurred? #
1. Calculate the change in score between test occasions
10 sec – 3 sec = 7 sec
2. Compare the MDC to the change in score. The MDC is 8.3 – 11.6 seconds for the SLS test.
7 sec < 11.6 sec
No, true change has not occurred because the difference between test occasions is less than the MDC of 11.6 seconds.
References #
- Westby MD, Brittain, A, Backman CL . Expert consensus on best practices for post-acute rehabilitation after total hip and knee arthroplasty: A Canada-US Delphi study. Arthritis Care Res. 2013. Sep 10. DOI 10.1002/acr.22164.
- Rehab Measures Database: Single Leg Stance or “One-Legged Stance Test” www.rehabmeasures.org/Lists/RehabMeasures/PrintView.aspx?ID=1150
- Springer BA, Marin R et al. Normative values for the unipedal stance Test with eyes open and closed. J Geriatr Phys Ther. 2007;30(1):8-15.
- Bohannon RW. Responsiveness of the single-limb stance test. Gait Posture 2012;35(1):173.
- Vellas B, Wayne S et al. One-leg balance is an important predictor of injurious falls in older persons. J Am Geriatr Soc. 1997;45:735-8.
- WHO International Classification of Functioning, Disability, and Health – http://www.who.int/classifications/icf/icf_more/en/
- Riddle, D. & Stradford, P. (2013). Is this Change Real? Interpreting Patient Outcomes in Physical Therapy. F.A. Davis Company: Philadelphia.