Functional Evaluation of High-Flex Total Knee Arthroplasty

ABSTRACT

PURPOSE: This study analyzed the functional result of High-Flex (HF) total knee arthroplasty (TKA) with focusing on the activities related to the Korean life style, and we identified the suitability of the presently used tools for performing functional evaluation. MATERIALS AND METHODS: We retrospectively analyzed 266 knees that underwent HF-TKAs with using a Scorpio-flex and the follow up period for all the knees was over 1 year. Functional evaluation was performed by questionnaire on activities, including cross-leg sitting, squatting, kneeling, standing from the floor, standing from a chair and ascending and descending stairs. The clinical evaluation included the Knee Society Knee Score (KSKS) & Function Score (KSFS), the WOMAC score and the patient's satisfaction score. The identification of suitable tools for the functional evaluation of high flexion activities was performed by statistical analysis. RESULTS: Deep flexion of the knees averaged 132.6degrees. Cross-leg sitting was possible for 90.6%, squatting for 32.3%, kneeling for 28.0%, standing from the floor for 66.9%, standing from a chair for 99.6%, ascending stairs for 96.2% and descending stairs for 90.6%. The WOMAC score and KSKS well differentiated the groups for the possibility of their activities, but the KSFS and patient's satisfaction did not differentiate between the groups for some activities. CONCLUSION: The functional evaluation after total knee arthroplasty with HF-TKA revealed good results on cross-leg sitting, standing from chair, ascending & descending stairs, but still poor results on squatting and kneeling. For the functional evaluation of HF-TKA, we believe that the WOMAC and KSKS are good evaluation tools. The KSFS and the patient's satisfaction need careful interpretation when using these for high flexion-related functional evaluation due to their lack of ability to differentiate between good and poor results by some activities.