AB0882 RELIABILITY OF THE 3-M BACKWARDS WALK TEST IN PATIENTS WITH REVISION TOTAL KNEE ARTHROPLASTY
Authors: B. Unver, K. Sevik, V. Karatosun
Journal: Annals of the Rheumatic Diseases (2020)

Background: Total knee arthroplasty (TKA) is an effective treatment for patients suffering from end-stage osteoarthritis with 10- to 15-year implant survivorship rates exceeding 90%. Infection, osteolysis due to polyethylene wear, loosening, stiffness and instability may cause to implant failure and revision of the TKA (rTKA). However, up to 20% of patients continue to have postoperative pain, functional limitations and low treatment satisfaction and 24% of patients were not able to walk unaided with no limp or a slight limp after TKA [1]. Falls and related traumas can produce “fracture, dislocation, crushing, and other injuries” [2]. Falls often occur due to impaired physical function which includes changes in lower knee joint angle, weakened lower limb muscles, peripheral nerve blockade, deformity of the foot limited balance and gait. Several measures of fall risk have been previously developed however, recent research has demonstrated that backwards walking is more sensitive at identifying changes in mobility and balance compared to forward walking. Backwards walking is necessary to perform such tasks as backing up to a chair, opening up a door or getting out of the way of a sudden obstacle. 3-M Backwards Walk Test (3MBWT) is used to evaluate walking skills, fall risk and dynamic balance. The 3MBWT demonstrated similar or better diagnostic accuracy for falls in the past year than the most commonly used measures and found to be reliable in healthy subjects. [3] However, its reliability in rTKA has not been investigated. Objectives: The purposes of this study were to determine the test-retest reliability and the minimal clinically important difference (MCID) of the 3MBWT in patients with rTKA Methods: Twenty-two patients with rTKA, operated on by the same surgeon, were included. For the 3MBWT, a distance of 3 meters was marked with tape and participants were asked to align their heels with the black tape. They were instructed to walk backwards as quickly. Patients performed trials for 3MBWT twice on the same day. Between the trials, patients waited for an hour on sitting position to prevent fatigue. Results: The 3MBWT showed an excellent test-retest reliability. Intraclass correlation coefficient ICC for 3MBWT was 0.97. The standard error of measurement and MCID at the 95% confidence level for 3MBWT were 1,08 and 2,99 respectively. Conclusion: The 3MBWT has an excellent test-retest reliability in patients with rTKA. It is an effective and reliable tool for measuring fall risk, dynamic balance and walking skills. As a clinical test, the 3MBWT is easy to score, has no cost, needs no special equipment and can be applied in a short time as part of the routine medical examination. References: [1]Shan L, Shan B, Suzuki A et al. Intermediate and long-term quality of life after total knee replacement: a systematic review and meta-analysis. JBJS 2015; 97: 156-168. [2]Johnson RL, Duncan CM, Ahn KS et al. Fall-Prevention Strategies and Patient Characteristics That Impact Fall Rates After Total Knee Arthroplasty. Anesthesia &amp; Analgesia 2014; 119: 1113-1118. [3]Carter V, Jain T, James J et al. The 3-m Backwards Walk and Retrospective Falls: Diagnostic Accuracy of a Novel Clinical Measure. J Geriatr Phys Ther 2017. Disclosure of Interests: None declared