Aims: The quality control of pediatric orthopaedic treatment options requires patient reported outcome measures that offer comparison to referenced populations. This study aimed to contribute to the validation of the Swedish translation of the norm-referenced PROMIS profile-25.

Methods: Three questionnaires were administered one year after an acute knee injury via the Swedish paediatric orthopaedic registry (SPOQ). The questionnaires were: (1) The PROMIS Pediatric Profile-25, including the short-forms Mobility, Anxiety, Depression, Fatigue, Peer Relationships, Pain Interference and the single-item Pain Intensity, translated following the FACIT translation method, (2) the Knee Injury and Osteoarthritis Outcome scales for children (KOOS-Child, previously validated in Swedish) with the scales Pain, Symptoms, ADL, Sport/play and QoL (39 questions), and (3) a single VAS item, Overall Health Scale. Convergent validity was assessed by interscale correlations and a one-way ANOVA was used to identify differences between three injury categories.

Results: Of 218 eligible patients, 104 (53 girls, 9-14 years, mean 13 years, 42 with patella luxation, 34 with anterior cruciate ligament rupture and 28 with other knee injuries), returned questionnaires. PROMIS and KOOS-Child had 1% incomplete answers. There was high positive correlation between all KOOS-Child scales, and KOOS-Child-Pain explained a large amount of variance in Symptoms (R2 = .610), ADL (R2 = .648), Sport/play (R2 = .462) and QoL (R2 = .423). An expected high correlation between KOOS-Child-pain and PROMIS-Pain-Interference was found (r = .581, p = \.001). The expected relationship between the PROMIS-Mobility scale and KOOS-Child-QoL (r = .815, p = \.001) was found, confirming that at this age QoL is associated with physical functioning. There were statistically significant differences between the three diagnosis categories for two PROMIS scales: PROMIS-mobility (F(2, 101) = 6.901, p = .002) and PROMIS-depression (F(2, 101) = 3.116, p = .049). The PROMIS subscales showed high Cronbach’s alpha (between 0.730 and 0.864).

Conclusions: This study is the first in Sweden to investigate the psychometric properties of the PROMIS profile-25 and highlights its relationship to the criterion measure of KOOS-Child. PROMIS-25 uses self-report, ultra-brief measurement for screening, providing additional information that was not available using previous questionnaires. PROMIS-25 can contribute to quality control and lead to improved treatment decisions. Data collection is ongoing through the orthopaedic registry, which will provide further evidence of how PROMIS-25 performs in other paediatric orthopaedic conditions.