The Validity and Reliability of the Thai Version of the Kujala Score for Patients with Patellofemoral Pain Syndrome

Purpose: To develop a Thai version of the Kujala score and show the evaluation of the validity and reliability of the score.

Method: The Thai version of the Kujala score was developed using the forward-backward translation protocol. The 49 PFPS patients answered the Thai version of questionnaires including the Kujala score, Short Form-36 (SF-36) and International Knee Documentation Committee (IKDC) Subjective Knee Form. The validity between the scores has been tested. The reliability was assessed using test-retest reliability and internal consistency.

Results: The Thai version of the Kujala score showed a good correlation with Thai IKDC Subjective Knee Form (Pearson's correlation coefficient; r = 0.74: p < 0.01) and moderate correlation with the Thai SF-36 subscales of physical component summary, total score and role physical (r = 0.586, 0.571 and 0.524, respectively: p < 0.01). The test-retest reliability was excellent with an intra-class correlation coefficient of 0.908 (p < 0.001; 95% CI [0.842-0.947]). The internal consistency was strong with Cronbach's alpha of 0.952 (p < 0.001). No floor and ceiling effects were observed.

Conclusion: The Thai version of the Kujala score has shown good validity and reliability. This score can be effectively used for evaluating Thai patients with patellofemoral pain syndrome. Implications for Rehabilitation The Kujala score is a self-administered questionnaire for patients with patellofemoral pain syndrome (PFPS). The validity and reliability of the Thai version of Kujala are compatible with other versions (Turkish, Chinese and Persian version). The Thai version of Kujala has been shown to have validity and reliability in Thai PFPS patients and can be used for clinical evaluation and also in the research work.