Validation of the new knee society knee scoring system for outcome assessment after total knew arthroplasty

Abstract

Introduction: This retrospective comparative study was to define the validity and reliability of a translated, culturally adapted Chinese version questionnaire of the New Knee Society Knee Scoring System (NKSS).

This study is aim to investigate the validity and reliability of the translated Chinese version of the NKSS and assess its feasibility of measuring the scale on Chinese patients by performing its cross-cultural adaptation for patients after Total Knee Arthroplasty (TKA) in Hong Kong.

Methods: A total of 104 knees from 64 Chinese patients performed TKA were included in the study using the translated, culturally adapted Chinese version of the NKSS. All Patients were operated on from October 2010 to May 2013 at Queen Mary Hospital. Patients who participated in this study have been clinically screened and established a set of including criteria. The outpatients were evaluated by completing the five questionnaires containing the NKSS, the Knee Society Clinical Rating System (KSS), Medial Outcomes Study 36+Item Short Form (SF-36), Bristol Knee Score and Oxford Knee Score.

Reliability was evaluated using the Split-half reliability, Chronbach's α coefficient and inter-item correlation. To assess validity, all patients filled in the same NKSS questionnaire, and previously validated Chinese version of the SF-36, Bristol Knee Score and Oxford Knee Score. The validity was determined with Content Validity and Contract Validity.

Results: The NKSS showed ideal split-half reliability as evidenced by the high correlation coefficient (R>0.7, P<0.05). Chronbach's α coefficient for five major domains demographics, objective knee score, expectations, satisfaction and function was high (α>0.7. P<0.05). Also, the inter-item correlation was also excellent for all domains. For validity, the NKSS was found to have excellent correlation with Bristol Knee Score and Oxford Knee Score, good correlation with KSS and SF 36

Discussion: The NKSS as a validated approach is adapted to the diverse health-related quality of lives and activities of contemporary patients with TKA. Orthopaedics surgeons are allowed to appreciate differences in the priorities of individual patients and the interplay among function, expectation, symptoms, and satisfaction after TKA using this assessment instrument.

Conclusion: The results of this study show that the NKSS as a functional status questionnaire has been translated into Chinese without missing any psychometric properties of the original version. This culturally and linguistics adapted Chinese version of the NKSS outcome assessment has satisfactory internal consistency and good validity. It is an adequate and helpful instrument for the evaluation of Chinese speaking patients after TKA in clinical studies.