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    Biomechanics

    (D-127) Knee Kinematics Asymmetry during Sit-to-Stand in Total Knee Arthroplasty Patients

    Friday, October 13, 2023
    9:30 AM – 10:30 AM PDT
    Location: Exhibit Hall - Row D - Poster # 127

      Presenting Author(s)

    • Theresa Libera, BS (she/her/hers)

      Ph.D. Candidate
      Virginia Tech
      Blacksburg, Virginia, United States

      • Co-Author(s)

    • KA

      Kelli Allen

      Professor of Medicine
      UNC - Chapel Hill, United States

      • Primary Investigator(s)

    • Robin Queen

      Professor
      Virginia Polytechnic Institute and State University, United States

    Introduction:: Total Knee Arthroplasties (TKAs) are the third most common orthopaedic surgery performed in the United States.1 As of 2022, approximately 750,000 surgeries are performed annually and the number is expected to double in the next decade.1  TKA is accepted as the optimal treatment for severe knee arthritis.2  However, 1 in 5 patients do not regain full physical function 10 years after the operation.3 Additionally, 40% of patients require the same surgery in the contralateral limb within 10 years of the primary TKA procedure.4 Asymmetries can be used to compare metrics between limbs to evaluate surgical interventions and injury risk during gait.5 Specifically, the Normalized Symmetry Index (NSI) has been seen to be a reliable and clinically relevant outcome measure.5 The sit-to-stand (STS) test is a widely accepted test for assessing physical function in older adults. The motion of standing from a seated position is a mechanically demanding task and is essential for independence.6 The purpose of this study was to determine differences in asymmetry between healthy older adults and patients following TKA using a 2D sagittal plane kinematic tracking system. It was hypothesized that asymmetry in knee joint angular kinematics during a 30-second STS test would be significantly greater in the TKA group compared to the healthy control group. 

    Materials and Methods:: A sample of 19 healthy older adults (11 females, 8 males) and 19 patients with a TKA (12 females, 7 males) were recruited. Control participants were excluded if they experienced lower extremity pain at the time of testing, were unable to walk without an assistive device, had sustained an injury in the last 2 months that limited physical activity for more than 2 days, or had a prior serious lower limb injury or surgery. Patients with a TKA were part of a larger randomized controlled trial examining the impact of physical therapy and physical activity and excluded if they had significant cognitive impairment, neurological disorders affecting gait, systemic rheumatic disease, hospitalization for a cardiovascular condition in the past 6 months, psychosis, substance abuse disorder, lower extremity surgery in the past year, or any other health conditions determined to be contraindications to participation. The TKA data was from a baseline assessment. Six retro-reflective markers were placed bilaterally on the lower extremity. The 2D sagittal plane kinematics were recorded using two GoPro cameras (GoPro, San Mateo, CA) collected at 120Hz. Participants were instructed to sit and stand as many times as possible in 30 seconds. Data was processed using AVADs.7 The NSI was calculated during each cycle, sitting to standing. The NSI was averaged across each cycle. Average knee range of motion (ROM) NSI was used for statistical analysis in JMP (SAS, Cary, NC). The NSI was compared between groups using a mixed effects model, using an alpha level of 0.05.

    Results, Conclusions, and Discussions:: The age (C: 65.2 ± 8.6yrs; TKA: 64.5 ± 7.2yrs; p >0.05), height (C: 1.7 ± 0.1m; TKA: 1.7 ± 0.1m; p >0.05), and weight (C: 75.4 ± 22.4kg; TKA: 87.2 ± 15.6 kg; p >0.05) were not different between groups. The average number of STS cycles completed within 30 seconds (C: 17.5 ± 5.0; TKA: 9.1 ± 1.5; p< 0.001) was significantly lower in the TKA group. Knee ROM NSI (C: 4.5 ± 2.0 %; TKA: 13.7 ± 11.6 %; p=0.002) was significantly different between groups, with a larger asymmetry seen in the TKA group. Additionally, in the TKA group, approximately 84% of participants had larger ROM values in the non-surgical knee. This study demonstrates that there is a higher knee ROM NSI in patients with a TKA during a STS task when compared to controls. These results agree with the literature indicating that patients with a TKA exhibit a significantly smaller average knee ROM compared to controls during a STS task.8 Additionally, the high percentage of participants favoring their nonsurgical leg reflects overloading in the limb, which could lead to the need for a contralateral TKA as has been reported in the literature.4 This data provides an understanding of the level of asymmetry during the STS task at baseline for patients with a TKA and can be used to understand how asymmetry changes following rehabilitation.


    Acknowledgements (Optional): :

    References (Optional): :

    1. Olsen,U. JAMA Net. Open. 2022; 5(7):e2219636-e2219636. 2. Lingard, EA. JBJS. 2004; 86(10):2179-2186. 3. Wieczorek, M. AC&R. 2020; 72(11):1519-1529. 4. McMahon, M. J. Rheumatol. 2003; 30(8):1822-1824. 5. Queen, R. J. Biomech. 2020; 99:109531. 6. Tsekoura, M. JFSF. 2020; 5(4):109. 7. Peebles, AT. Ann Biomed Eng. 2021; 49(1):455-468. 8. Jevsevar, DS. PT. 1993; 73(4):229-239.