The German version of the High-Activity Arthroplasty Score is valid and reliable for patients after total knee arthroplasty

Purpose

The indications for a total knee arthroplasty (TKA) broadened to younger and more active patients. The High-Activity Arthroplasty Score (HAAS) is a self-administered instrument focussing on the wider range of functional abilities of more active patients. The HAAS was developed in English and is not available in German yet. This study aims to translate, cross-cultural adapt and assess the psychometric properties of the German HAAS in patients 12 months after primary TKA.

Methods

After forward and backward translation, we examined the final version regarding its psychometric properties in patients 12 months after primary TKA. The HAAS was sent out to 70 patients together with routine questionnaires comprising the Knee injury and Osteoarthritis Outcome Score (KOOS), the Forgotten Joint Score (FJS-12), the EuroQol (EQ-5D-3L) and 2 numerical pain rating scales. Acceptability, reliability, responsiveness, content and construct validity as well as floor and ceiling effects were evaluated.

Results

Fifty-two patients were recruited. The HAAS was well accepted with a mean time to completion of 2.4 min. Cronbach’s alpha for internal consistency was 0.749, test–retest reliability was excellent with an Intraclass Correlation Coefficient (ICC) of 0.961. The smallest detectable change was 1.5. Good content validity was confirmed. A strong correlation was found between the HAAS and KOOS sport (r = 0.661) and a medium correlation for all other KOOS subscales (r = 0.324 to 0.453), the FJS-12 (r = 0.425), the EQ-5D-3L (r = 0.427) and pain (r = − 0.439 to − 0.308). The HAAS showed no floor and ceiling effects.

Conclusions

The German version of the HAAS provides good validity and reliability. It can be easily self-administered and is recommended to capture high-intensity activities in patients after TKA.

Level of evidence

Diagnostic study, Level I.