Background: The Lysholm knee scale is a condition-specific outcome
measure that was originally designed to assess ligament injuries of the knee.
The purpose of this study was to determine the psychometric properties of the
Lysholm knee scale for various chondral disorders of the knee.
Methods: Test-retest reliability, internal consistency, content
validity, criterion validity, construct validity, and responsiveness to change
were determined for the Lysholm knee scale within subsets of an overall study
population of 1657 patients with chondral disorders of the knee. The study
population was a heterogeneous group of patients with various types of
traumatic and degenerative chondral lesions, including isolated lesions and
those associated with meniscal and ligament injuries.
Results: The overall Lysholm knee scale and six of the eight domains
had acceptable test-retest reliability (intraclass correlation coefficient =
0.91) and internal consistency (Cronbach alpha = 0.65). The overall Lysholm
knee scale demonstrated acceptable floor (0%) and ceiling (0.7%) effects;
however, the floor effects for the domain of squatting and the ceiling effects
for the domains of limp, instability, support, and locking were unacceptable
(>30%). There was acceptable criterion validity with significant (p <
0.05) correlations between the overall Lysholm knee scale and the physical
functioning, role-physical, and bodily pain domains of the Short Form-12
scale; the pain, stiffness, and function domains of the Western Ontario and
McMaster Universities Osteoarthritis Index; and the Tegner activity scale. The
overall Lysholm knee scale had acceptable construct validity, with all nine
hypotheses demonstrating significance (p < 0.05), and it had acceptable
responsiveness to change (effect size, 1.16; standardized response mean,
1.10), with large effects (=0.80) for the domains of pain, limping,
swelling, and squatting and a small effect (=0.20) for the domain of
instability.
Conclusions: The Lysholm knee scale demonstrated overall acceptable
psychometric performance for outcomes assessment of various chondral disorders
of the knee, although some domains demonstrated suboptimal performance.
Psychometric testing of other condition-specific knee instruments in patients
with chondral disorders of the knee would be helpful to allow for comparison
of psychometric properties.