Revista de Medicina Desportiva (English) November 2018 | Page 20

Rev. Medicina Desportiva informa, 2018; 9(6):18-22.
Injuries to the Posterior-
Lateral Corner of the Knee
Dr. Carlos Mesquita Queirós 1 , Dr. Alcindo Silva 2
1
IResident on Orthopedics at the Centro Hospitalar Entre Douro e Vouga, Santa Maria da Feira;
2
Orthopedic and Traumatology Specialist Hospital da Luz Arrábida, V N Gaia
RESUMO / ABSTRACT
Posterolateral corner lesions of the knee occur frequently alongside other ligament lesions, and
are amongst one of the major causes of failure in anterior cruciate ligament reconstructions and
degenerative arthritis. Anatomical and biomechanical research reveals the importance of three
lateral strutures: lateral collateral ligament, popliteus muscle, and poplitealfibular ligament. For
accurate diagnosis the physical examination, the stress radiographs and the MRI are indispensable.
Treatment of high-grade lesions should be surgical, with improved clinical outcomes reported by
anatomical techniques.
Injury
PALAVRAS-CHAVE / KEYWORDS
Knee, posterolateral corner, posterolateral reconstruction, lateral instability knee
Introduction
It is historically referred as the
obscure side of the knee, the pos-
terior-lateral corner (PLC) has been
subject of renovate attention. The
injuries of the PCL are quite often
associated to other ligament injuries
and they are noxious if not timely
recognized, being one common
cause of failure after anterior cruci-
ate ligament (ACL) reconstruction
and also mechanical changes in the
knee with subsequent early articular
degeneration. 1-5
To identify these injuries there
should be a high suspicion and a
strict and systematic physical exam
is needed. To find the injured struc-
tures it is indispensable the detailed
evaluation of the complementary
diagnostic exams, like the X-ray and
the magnetic resonance (MRI). 6,7
The conservative treatment for
the high degree injures doesn’t have
satisfactory results 8 , which has been
recently motivating the description of
several techniques for reconstruction.
In this paper it will be reviewed
the surgical anatomy of the PLC, the
clinical diagnosis, the image study
and the treatment.
Anatomy
The most important structures
for lateral stabilization are deeper
18 november 2018 www.revdesportiva.pt
in relation to the femur. In case of
insufficiency of the cruciate liga-
ments, this structure also provides
secondary stabilization to the poste-
rior and anterior translation. 11,12
The LCL is the primary restrictor to
the varus forces and all other struc-
tures act as secondary restrictors. 4,14
In relation to the external rotation,
the principal restrictors are the LCL
and popliteus complex (PPL and the
popliteus tendon). The PCL acts as
secondary restrictor. 14-17
Both in the internal rotation and
on anterior-posterior stabilization,
the PLC has a secondary role with
functioning cruciate ligaments. 4,14,15
located, like the lateral collateral lig-
ament (LCL), the popliteus-peroneal
ligament (PPL) and the popliteus
tendon. 12 The LCL is the primary
stabilizer for the varus forces. 4,14,15 It
originates in a proximal and small
cavity posterior to the lateral epicon-
dyle, runs under the iliotibial band
and the femoral biceps tendon to
its insertion on the lateral aspect of
head of the fibula. 9,16
The popliteus muscle originates at
the posterior-lateral area of the tibia,
runs proximally and laterally to the
insertion on the popliteus sulcus of
the femur. The fact that the average
distance between its insertion and
the one of the LCL is 18,5mm has
clinical importance, since due to this
difference a unique femoral graft
can not reproduce the tensioning
at different angles of flexion (Figure
1). 9,16
The PPL is an important stabilizer
to the external rotation and second-
ary restrictor to the varus forces in
the knee. It is a fibrous structure
that connects the popliteus tendon
to head of the fibula (Figure 2). 9
It is a high-energy injury and it is
associated with high-impact sports,
where the most probable cause is
the combination of a direct force
applied to the medial face of the
tibia, applied posterior-lateral, with
extension of the knee. 18 There are
frequently associated severe liga-
ment injuries, like knee dislocation. 18
The injuries on the PLC are rarely
isolated, although in the majority of
the cases they are associated to the
PCL. On meta-analysis published
with 456 patients there were 12% of
isolated injuries, 23% with rupture of
the ACL, 59% with the PCL and in 6%
with the PCL and ACL. 19
Diagnosis
The injury can be detected on the
acute or chronic phases. Clinically,
on the acute phase, the patients
have pain, lateral exuberant edema
Biomechanics
The biomechanics role of the
posterior cruciate ligament (PCL)
consists on the restriction to the
primary varus forces and also to the
posterior-lateral rotation of the tibia
Figure 1 – The principal stabilizers of the
posterior-lateral corner
https://ars.els-cdn.com/content/image/1-s2.0-
S010236161400277X-gr1.jpg