The Harris hip score: Do ceiling effects limit its usefulness in orthopedics?
OBJECTIVE
The Harris hip score (HHS), a disease-specific health status scale that is frequently used to measure the outcome of total hip arthroplasty, has never been validated properly. A questionnaire is suitable only when all 5 psychometric properties are of sufficient quality. We questioned the usefulness of the HHS by investigating its content validity.


METHODS
We performed a systematic review based on a literature search in PubMed, Embase, and the Cochrane Library for descriptive studies published in 2007. 54 studies (59 patient groups) met our criteria and were included in the data analysis. To determine the content validity, we calculated the ceiling effect (percentage) for each separate study and we pooled data to measure the weighted mean. A subanalysis of indications for THA was performed to differentiate the populations for which the HHS would be suitable and for which it would not. A ceiling effect of 15% or less was considered to be acceptable.


RESULTS
Over half the studies (31/59) revealed unacceptable ceiling effects. Pooled data across the studies included (n = 6,667 patients) suggested ceiling effects of 20% (95%CI: 18-22). Ceiling effects were greater (32%, 95%CI:12-52) in those patients undergoing hip resurfacing arthroplasty.


CONCLUSIONS
Although the Harris hip score is widely used in arthroplasty research on outcomes, ceiling effects are common and these severely limit its validity in this field of research.
Department of Orthopaedic Surgery, Academic Medical Centre, Amsterdam, the Netherlands.
Kim E
KE
Wamper
Inger N
IN
Sierevelt
Rudolf W
RW
Poolman
Mohit
M
Bhandari
Daniël
D
Haverkamp
D019644:Arthroplasty, Replacement, Hip / Q000009:adverse effects; D019317:Evidence-Based Medicine; D006304:Health Status; D006801:Humans; D017063:Outcome Assessment, Health Care; D011594:Psychometrics; D011788:Quality of Life; D020127:Recovery of Function; D016896:Treatment Outcome