Abstract:
Purpose:
Accurate knowledge of the anatomy of the anterior cruciate ligament (ACL) is crucial
for successful ACL reconstruction. Incorrect graft lengths and/or tunnel
misplacement have to be avoided. If the graft length is incorrect, the patient could
risk knee instability, loss of range of motion or failure of graft fixation. The success of
ACL reconstruction will be enhanced if the correct length of the graft ligament
required, can be predicted in advance. Magnetic resonance imaging (MRI) is
currently used for the evaluation of ACL injuries, but is not available to all patients.
Apart from examining the morphological properties of the ACL at macroscopic and
microscopic levels, this study aimed to determine whether independent factors of an
individual can be used to predict native ACL length which could assist in preoperative
planning.
Methods:
Ninety-one adult cadavers were studied. The patellar ligament (PL) length, ACL
length, ACL width and the maximum femoral epicondylar width (FECW) were
measured. For the radiographic component, 52 patients were sourced to evaluate
and compare ACL length, PL length and FECW, measured on both MRI and
radiograph. Fresh ligaments were harvested (18 ACLs and 10 PLs) to evaluate the
histological composition of the ACL and PL.
Results:
The morphology of the ACL and PL was determined. The morphology of the
ligaments compared well to the descriptions in previous literature. The ligaments
proved to be compatible at histological level. The results revealed that FECW was
the most reliable predictor of ACL length. Linear regression formulas were developed
in order to determine ACL length by measuring maximum FECW. It was also
determined that either an MRI or radiograph can be used to assist in pre-operative
planning.
Conclusion:
ACL and PL morphology compared well with the descriptions found in previous
studies. It was also found that, contrary to previous studies, the maximum FECW is a
more reliable predictor of ACL length than the height of the patient. The results also
showed that both radiographs and MRI scans can be used to determine preoperative
ACL length. These results could improve the pre-operative planning of
ACL reconstruction and minimise the occurrence of graft mismatch.
