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DEFINITION: WHAT IS A
PARTIAL TEAR?
There is no true definition of a partial tear of
the anterior cruciate ligament (ACL) in the
literature. For Bak [3], “the term partial ACL
tear is a tentative diagnosis based on a histo-
ry of a twisting injury with subsequent hae-
marthrosis and a negative or slightly positive
Trillat-Lachman test”. For some authors [14,
18] a partial tear is an isolated rupture of
either one of the two bundles and more often
the anteromedial bundle. But for others [31,
32], it’s an interstitial tear. Another definition
could be a complete ACL tear which has hea-
led to the lateral wall [11] or onto the poste-
rior cruciate ligament.
Based on our experience, we can observe dif-
ferent clinical situations: the first case is a
patient with a positive Trillat-Lachman
(grade B), no pivot shift and only 3mm of
differential anterior tibial translation (
Δ
ATT)
as measured radiologically with Telos, and
indication on magnetic resonance imaging
(MRI) for ACL involvement. The second case
is a patient with an almost normal clinical
examination and only a delayed hard end
point on the Trillat-Lachman test but with an
important radiological laxity (
Δ
ATT>8 mm).
The MRI appearance of the ACL is this case
is generally protocolled as normal.
Irrespective of the anatomical type of ruptu-
re, the most important point is the residual
laxity.
HOW SHOULD WE ANALYSE
THE LAXITY OF A PARTIAL
TEAR?
Theorically, in patients with a partial ACL
tear, we can observe a Trillat-Lachman test
grade B or delayed hard end point but no
pivot shift. However in case of an isolated
tear of the posterolateral bundle, a pivot-
shift test might be found [28]. For Chun [9],
the symptomatology may be a pseudo-loc-
king knee. Actually, the clinical examination
is often doubtful [3, 4, 19, 22] and additional
magnetic resonance imaging is considered
helpful.
According to Chen [8], a focal increase of the
signal intensity was suggestive of a partial
tear but Umans [33] showed that MR evalua-
tion of partial ACL tears is not sufficiently
sensitive to establish the diagnosis.
119
HOW SHOULD WE TREAT A PARTIAL TEAR
OF THE ANTERIOR CRUCIATE LIGAMENT?
E. SERVIEN, P. VERDONK, S. LUSTIG, PH. NEYRET