Background: The effect of total knee arthroplasty on proprioception,
kinesthesia, and postural control remains controversial. It is argued that
retaining the posterior cruciate ligament may help to preserve these
sensorimotor functions and improve the longevity of the prosthesis and the
functional outcome. We performed a prospective, randomized study to assess
proprioception, kinesthesia, and balance following total knee arthroplasty
with cruciate-retaining and posterior stabilized prostheses.
Methods: Twenty patients scheduled to undergo total knee
arthroplasty were randomly assigned to receive either a cruciate-retaining or
a posterior stabilized prosthesis. Joint-position sense, the threshold to
detect joint motion, and the subject's ability to balance on an unstable
platform were assessed prior to and at least six months after the operation.
Paired two-tailed t tests (with a level of significance of p < 0.05) were
used to assess the effect of the arthroplasty on the preoperative measures for
all subjects. Analysis of covariance was performed to identify the effects of
prosthetic design.
Results: Following total knee arthroplasty, patients detected motion
significantly faster and reproduced joint position with less error. The
balance index also improved significantly from the preoperative to the
postoperative evaluation. The group treated with the posterior stabilized
prosthesis more accurately reproduced joint position when the knee was
extended from a flexed position.
Conclusions: Total knee arthroplasty results in mild improvements in
proprioception, kinesthesia, and balance. These changes may result from the
retensioned capsuloligamentous structures and reduced pain and inflammation.
Retention of the posterior cruciate ligament does not appear to significantly
improve proprioception and balance compared with those functions in patients
with a posterior stabilized total knee design.
Level of Evidence: Therapeutic study, Level I-1a
(randomized controlled trial [significant difference]). See Instructions to
Authors for a complete description of levels of evidence.