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BACKGROUND
Studies have demonstrated that tibiofemoral
instability is one of the common reasons
within 2-5 years of early failure in total knee
arthroplasty. In 21% to 27%, instability was
the aetiology for revision [1-3]. To avoid these
failures in performing total knee arthroplasty
(TKA), the following steps have been empha-
sized: a detailed preoperative evaluation, res-
toration of the axial alignment of the lower
extremity [3-5] and adequate soft tissue liga-
ment balance in the flexion and extension gaps
[3, 5-7].
The full leg bipodal X-ray is useful for a detai-
led analysis of the deformity, whether it is
intra-articular or extra-articular [8-12]. The
articular part of the deformity is caused by the
cartilage and bone wear of the tibial plateau
with the contractures of the soft tissues. Extra-
articular deformity, often seen on the proximal
tibia, may be located anywhere in the femur or
tibia along its anatomic axis either constitutio-
nal or as the result of an acquired deformity
[13, 14]. However, it remains unclear how to
analyze the reducibility of the deformity
during the preoperative evaluation in osteoar-
thritic knees and also, which varus or valgus
deformity is correctible by surface replace-
ment without soft tissue release.
So far the clinical examination still remains
the common way to assess the reducibility of
the deformity, but it is subjective [15-17].
Therefore, quantitative instrumented measure-
ments by varus and valgus stress have been
performed in the evaluation [18-21].
In several articles, it has been mentioned that
varus/valgus stress X-rays are useful to plan pri-
mary TKA [22-24], but there is no report in the
literature concerning the quantitative assessment
of preoperative stress radiographs to surgery.
Thus, this study was designed to look at the
issue of “correctability” of varus malalignment
in osteoarthritis of the knee and whether preope-
rative stress radiographs could guide intraopera-
tive decision making, particularly with regard to
medial soft-tissue releases. The term laxity, as
used, was descriptive as a radiologic parameter
due to opening or closing of the medial and late-
ral compartment under varus/valgus stress. We
hypothesized that these stress X-rays are helpful
to evaluate the soft tissue structures around the
medial compartment and also to plan the soft tis-
sue release procedures in the osteoarthritic knee
undergoing TKA.
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ARE STRESS X-RAYS USEFUL TO PLAN MEDIAL
SOFT TISSUE RELEASE PROCEDURES IN TOTAL
KNEE ARTHROPLASTY?
A.D. KARA, E. SERVIEN, S. LUSTIG,
J. HENRY, T. AÏT SI SELMI, PH. NEYRET