The validity and reliability of the Thai version of the Kujala score for patients with patellofemoral pain syndrome

Abstract

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.

Keywords:

• Kujala score
• patellofemoral pain score
• reliability
• Thai version
• validity

Acknowledgements

We would like to thank Prof. Urho M Kujala for permitting us to validate the Kujala score. Thanks to Zia Collinsfree, Chorthip Viriya, Husna Phettongkam, Keerata Apichonpakdi and Pracharee Amatayakuland for their assistance in the translation process. Thanks to Kamolrat Wannachoochai (our research assistant) for the data collection.

Declaration of interest

The authors report no conflicts of interest. This study received financial support from faculty of medicine, Thammasat University, Thailand.