POSTER ABSTRACTS - ISAKOS

epicondylar axis (EA) or the posterior condylar
axis (PCA) have all been used to locate the
optimal position for femoral component rotation.
We have assessed the anterior femoral cortical
line (AFCL) as a reproducible landmark in the
femur.
Methods:
We analysed the rotational position of the AFCL
with respect to the EA using axial MRI scans of 32
knees. Each line was identified using defined
criteria and reproducible landmarks and the angle
between them measured on the medial side of the
axial slice to determine a mean value. The process
was repeated for the APA and the PCA and the
results analysed.
Results:
The mean total value for the AFCL with respect to
the EA was 11.3º (range 5 - 18, Standard Deviation
3.22) measured on the medial side of the knee
(internally rotated with respect to the EA). There
was no statistically significant difference between
right and left knees or men and women.
Measurements derived from the other landmarks
were similarly consistent.
Conclusion:
The anterior femoral cortical line is a
reproducible landmark in the knee with a
relatively consistent relationship with other axes
of femoral rotation. It may be useful when
determining optimal rotation for the femoral
component, particularly in revision surgery or
other circumstances where other landmarks may
be lost. We are currently analysing greater
numbers to confirm the data presented in this
initial study.
E-poster #541
Revision Total Knee Arthroplasty: Baseline
Information from the North American Knee
Arthroplasty Revision (NAKAR) Study Group.
North American Knee Arthroplasty Revision
(NAKAR), USA
Edward Ranier Santos, Minneapolis, Minnesot
USA
Khaled J. Saleh, Charlottesville, VAUSA
Kevin James Mulhall, Charlottesville, VA USA
Presenter
University of Minnesota, Minneapolis, MN, USA
Introduction: Revision total knee arthroplasty
(TKAR) is on the rise. There is a paucity of
information regarding the demographic
characteristics, etiology or mode of failure,
functional disability, and socioeconomic status of
patients Presenter for TKAR. The objective of this
seventeen-center prospective study is to
document pertinent baseline information on
candidates for TKAR.
Methods: The cohort consisted of 290 consecutive
subjects Presenter for TKAR from March 2002 to
December 2003. Baseline demographic data were
retrieved from standard patient-completed
questionnaires. Relevant clinical information was
obtained from surgeon-completed documents.
Subjects enrolled in the study also completed
quality of life and functional questionnaires,
including the Short-form 36 (SF-36) and Western
Ontario and McMaster Universities (WOMAC)
Osteoarthritis Index. Modes of failure were also
recorded.
Results: There were 137 males and 153 females
with a mean age of 68.6 years (34 to 85 years). The
mean SF-36 and WOMAC score at baseline
indicated significant functional disability. The
subjects were composed of Caucasian (83%),
African-American (14%) and other races (3%).
Approximately 20% of the subjects had only
primary education, 34% graduated from high
school, 22% had some college education, 13%
graduated from college, and 9% had a
postgraduate degree. Thirty-nine percent of the
patients had an annual household income below
$25,000; 31% were in the $25,000-$50,000 bracket,
and 22% had annual incomes greater than
$55,000. The predominant modes of failure were
instability (28.9%), tibial osteolysis (27.5%),
polyethylene wear (24.5%), femoral osteolysis
(22.5 %) and tibial loosening (22.2%)
Conclusion: We were able to define baseline
demographics for 290 consecutive TKAR cases.
The results show that these patients are relatively
young, and considerably disabled by their failed
primary procedure. Majority of the patients had
lower educational and income status, and lacked
health care coverage, a fact that becomes more
significant in light of the generally high cost of
these revision procedures, as well as the greater
awareness of health care cost in general. The
modes of failure were similar to those in previous
studies and consist of instability,osteolysis,
polyethylene wear, and aseptic loosening. The
findings give us insight into the specific groups of
TKA patients that are at risk for failure and may
allows the formulation of measures and proper
resource allocation that may prevent TKARs.