Keywords
chronic ACL and PCL injury - ACL laxity tests - association between ACL laxity tests
and arthroscopy findings
An anterior cruciate ligament (ACL) injury may be diagnosed by clinical examination
and radiological investigation using magnetic resonance imaging (MRI) or by arthroscopy.[1]
[2] Based on our experience, the ACL tear in concomitant chronic ACL and posterior cruciate
ligament (PCL) deficient knees may produce knee laxity, which is more difficult to
assess on clinical examination, which in turn may affect the management algorithm
of the patient. Our hypothesis is that, in a concomitant chronic ACL and PCL injury,
posterior capsular contracture and abnormal reattachment of torn ACL will result in
less clinical and subjective laxity, preoperatively. The aim of this study is to review
a cohort of patients who had undergone PCL reconstructive surgery and compare the
preoperative clinical assessments with and without anesthesia with arthroscopic finding
of ACL.
Methodology
This study was a retrospective analysis of all 38 patients with chronic PCL tear (>
6 weeks post injury), who underwent PCL reconstruction in 2012 and 2013 in our center.
In all the cases, the clinical diagnosis of chronic PCL with or without ACL injury
was made after examination by the senior author through three clinical examinations
comprising (1) Lachman test,[3]
[4] recording the degree of anterior laxity (normal, 3–5mm, 6–10 mm or > 10 mm) and
the quality of the end point (firm, intermediate, or absent); (2) anterior drawer
test[3]
[4] and (3) pivot shift test,[3]
[4] and an optional MRI scan, when there was diagnostic uncertainty. Preoperative clinical
function was assessed using the International Knee Documentation Committee Subjective
Knee Evaluation Form[5] within 2 days prior to surgery. At the time of surgery, the same three clinical
examinations were performed under anesthesia by the senior author. No arthrometry
was performed. Intraoperatively, the arthroscopic appearance of the ACL was classified
as intact, partial, or complete tear.[6]
Results
Data was collected from 38 patients who were diagnosed and underwent PCL reconstruction
surgery to the knee. Seventeen cases had ACL and PCL injury, while 21 cases had combined
multiligament injuries involving ACL, PCL, and collateral ligaments. The cohort of
patients reviewed consisted mainly of males, aged between 26 and 35, and injuries
were mainly due to motor vehicle accidents ([Fig. 1]). Of the 38 patients who underwent surgery, 25 (66%) patients suffered from ACL
injuries, of which 23 (55%) suffered from total ACL tear, whereas 2 (11%) suffered
from partial ACL tear ([Fig. 2]). Based on the data collected, all clinical examinations were found to be highly
inaccurate with disparity ranging between 67% and 100% as compared with arthroscopy
findings ([Fig. 3]).Comparatively, clinical examinations performed under anesthesia were better to
indicate ACL tears than preoperative tests, with anterior drawer test 7(33%) and Lachman
6(29%) tests providing significantly better results than preoperative tests without
anesthesia ([Fig. 3]).
Fig. 1 Demography of patients. Abbreviation: MVA, motor vehicle accident.
Fig. 2 Preoperative clinical findings with and without anesthesia for ACL injuries versus
arthroscope. Abbreviations: ACL, anterior cruciate ligament; ADT, anterior drawer
test; UA, under anesthesia.
Fig. 3 Preoperative clinical examination without anesthesia tests is less able to indicate
complete ACL tears than examinations UA. Abbreviations: ACL, anterior cruciate ligament;
ADT, anterior drawer test; UA, under anesthesia.
Discussion
We found that in chronic PCL injury knees the accuracy of preoperative clinical examination
for ACL laxity with or without anesthesia is low. Although preoperative examination
under anesthesia is more sensitive compared with the preoperative examination without
anesthesia, it was still less accurate based on the intraoperative arthroscopic findings.
Preoperative test without anesthesia was virtually ineffective in indicating ACL tears
in patients with ACL tear, with two of three clinical examinations yielding no indication
of ACL tears in any patient. This may be due to the posterior capsular contracture
in chronic PCL injury or an abnormal reattachment of torn ACL. Muscle relaxation during
the examination under anesthesia might also influence the findings. We believe that
our findings should be borne in mind when examining a knee with chronic PCL injury
of a possible concomitant ACL injury.
Conclusion
In chronic PCL injury, preoperative examination with or without anesthesia alone may
give an inaccurate finding to determine the diagnosis and grading of ACL laxity. The
diagnosis and management of ACL injuries should be based on the history, clinical
examination, and arthroscopic findings. MRI should be interpreted with caution as
the reattached ligament may be confused with a partially injured or uninjured ligament.
