POSTER ABSTRACTS - ISAKOS

subjective or objective measurement between the
failures and the non-failures within the follow-up
period.
For the non-failure group average follow-up was
30 months (range 24 to 40). Average Lysholm was
71 (range 19 to 100), with an average improvement
of 30 points (range -15 to 95). Knees with greater
than a 20% shift in WBA had follow-up lower
Lysholm scores (70) at follow-up compared to
knees with less than 20% shift (Lysholm=79)
(p=0.045). The average Tegner was 4 (range 0 to
8). Average patient satisfaction was 8 (range 1 to
10). Average WOMAC pain was 4 (range 0 to 14),
WOMAC stiffness was 2 (range 0 to 4), and
WOMAC function was 12 (range 0 to 47).
Independent predictors of improvement in
Lysholm score included shift in WBA, and pre-op
Lysholm score.(r2=0.43)
Conclusion: This comprehensive arthroscopic
treatment regimen and post-operative physical
therapy program can improve function and activity
levels in patients with significant OA and can
delay arthroplasty. However, patients with
severe varus or valgus deformity and lower pre-op
Lysholm scores may expect significant but lesser
degrees of improvement.
E-poster w/ Standard #557
Development of a Composite Improvement
Scale in a Prospective Multi-centre Study of
Total Knee Arthroplasty Revision.
Khaled J. Saleh, Charlottesville, VA, USA,
Kevin James Mulhall, Charlottesville, VA USA
Presenter
North American Knee Arthroplasty Revision
(NAKAR), Study, Group USA
Universiy of Minnesota, Minneapolis, MN, USA
Introduction:
Improvement is the ultimate objective of any total
knee arthroplasty revision (TKAR) procedure.
Improvement is however a multi-dimensional
concept. Although there are numerous
instruments available for the assessment of knee
arthroplasty patients it can be difficult to
ascertain which is the most appropriate or how
these tests complement each other. The purpose
of this paper was to develop a novel analysis of
the structure of improvement by devising a novel
improvement scale for total knee arthroplasty
revision (TKAR) using validated generic and
disease-specific quality of life measures.
Methods:
As a part of a seventeen-center prospective cohort
study, 186 consecutive patients undergoing TKAR
had data collected on SF-36, the Western Ontario
and McMaster Universities Osteoarthritis
(WOMAC) Index, the Knee Society Score (KSS),
the Activity Scale (AS), and physician assessment
of patient severity a baseline and 6-month followup.
Factor analysis was applied to change in
scores between the two time points
(standardized) for all instruments to derive an
improvement scale.
Results:
Improvement in mean scores for respondents
from baseline to follow-up (97% response rate)
were significant for all measures except for SF-36
MCS. Improvements on individual scales were
either non correlated or significantly correlated
and positive. Factor analysis was performed to
identify possible patterns of improvement among
these measures. Four factors were elucidated.
Factor 1 was mainly composed of change in SF-36
PCS and WOMAC components. Factor 2 was
mainly based on change in KSS- functional
component and physician assessment of patient
severity and change in AS score. Factor 3
depended mainly on change in SF-36 MCS; factor
4 depended mainly on change in KSS-knee
assessment. Factors 1 and 2 showed high internal
consistency (factor 1: Cronbach Alpha =0.77;
factor 2: Cronbach Alpha =0.64). Four variables
were created as a result of factor analysis. Mean
scores for these variables were large and positive.
Correlation between these variables was