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Journal article

Psychometric properties of the Norwich Patellar Instability Score in people with recurrent patellar dislocationn

Abstract:

Background

Patellar dislocations account for two percent of all knee injuries with a 17% chance of re-dislocation. There are few validated scores specific to instability. One of these is the Norwich Patellar Instability Score. There has been limited assessment of the validity, floor-ceiling effect and responsiveness of the Norwich Patellar Instability (NPI) Score from an independent centre. The purpose of this paper is to address this limitation.

Methods

Data from 90 patients referred to a tertiary referral patellofemoral clinic were analysed. All routinely completed data including NPI Score, Kujala Patellofemoral Disorder Score, and demographic outcomes during appointments, up to 36 months following initial clinical assessment was analysed. Convergent validity was assessed by correlating outcomes of the Kujala Patellofemoral Disorder Score to the NPI Score. Effect size (ES) was determined between baseline to 12-month and 12 to 36-month assessments to determine responsiveness. Floor-ceiling effect was evaluated at baseline, 12-month and 12 to 36-month follow-up.

Results

NPI Score demonstrated good convergent validity to the Kujala Patellofemoral Disorder Score (p < .001; 95% confidence interval (CI): − 0.71 to − 0.52). NPI Score demonstrated good responsiveness to change both between baseline to 12 months (ES: 0.43; 95% CI: 0.42 to 0.10) and 12 to 36 months (ES: 0.67; 95% CI: 0.60 to 0.15). Whilst the NPI Score did not demonstrate a ceiling effect, there was moderate risk of a floor-effect where 13% of the cohort reported the lowest levels of NPI scores.

Conclusions

The NPI Score is a valid and responsive outcome for people with recurrent patellar dislocation.

Publication status:
Published
Peer review status:
Peer reviewed

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Publisher copy:
10.1016/j.knee.2019.10.021

Authors


More by this author
Institution:
University of Oxford
Division:
MSD
Department:
NDORMS
Role:
Author


Publisher:
Elsevier
Journal:
Knee More from this journal
Volume:
26
Issue:
6
Pages:
1192-1197
Publication date:
2019-11-23
Acceptance date:
2019-10-24
DOI:
EISSN:
1873-5800
ISSN:
0968-0160


Language:
English
Keywords:
Pubs id:
pubs:1064304
UUID:
uuid:6fe64e60-2d00-4890-b852-15410c334811
Local pid:
pubs:1064304
Source identifiers:
1064304
Deposit date:
2019-10-24

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