1
MPFL R ECONSTRUCTION
Lateral
patellofemoral
instability
is
characterized by a deficiency of the medial
patellofemoral retinacular soft tissues due to
ligamentous laxity and/or injury. 1,2,5 These
medial retinacular structures include – (1) the
medial patellofemoral ligament, (2) the medial
patellotibial
ligament,
(3)
the
medial
patellomeniscal ligament, and (4) the
superficial medial retinaculum. However, the
current body of evidence indicates that the
medial patellofemoral ligament (MPFL) serves
as the primary passive restraint preventing
lateral displacement of the patella. Clinical
studies have shown the majority of acute
lateral patellar dislocations result in complete
or partial tears to the MPFL. 1 Likewise,
conditions such as trochlear or soft tissue
dysplasias can predispose a patient to
recurrent patellar dislocation or subluxation
and subsequent injury and hyperlaxity of the
medial soft tissues. 1,2,5
I NDICATION FOR MPFL R ECONSTRUCTION
MPFL Reconstruction is indicated in patients
with lateral patellar instability, caused by tears
or laxity of the MPFL. The patient often has a
a history of acute or recurrent patellar
dislocation and/or patellar subluxation. 2
A N A NATOMICAL MPFL R ECONSTRUCTION
In light of the fact that the MPFL has been
identified as the primary passive restraint to
patellar lateral displacement, reconstruction of
the MPFL can provide the best clinical
outcomes by restoring the normal limits of
patellar
motion. 1
Accurate
anatomical
reconstruction of the native anatomy and
biomechanics of the MPFL is imperative to
achieve an effective reconstruction. 3
Between 0° and 70° of flexion, the native
MPFL is isometric in length and tension is
minimal; beyond 70° of flexion, the MPFL
becomes lax and tension is negligible or zero. 3
The femoral attachment site has been shown
to have the greatest effect on MPFL isometry.
Studies indicate that
a nonanatomic
reconstruction where the graft is proximally or
distally malpositioned at the femoral
attachment site by only 5 mm can cause
significant nonisometric length changes
resulting in abnormal graft tension and
elevated forces in the medial patellofemoral
joint. 3,4 Consequently, accurate placement of
the femoral reattachment site has been
identified as the most significant factor
influencing surgical outcome. 4
T HE T ECHNIQUE
The following technique, developed by Dr.
Jack Farr, II, reproduces the anatomy of the
MPFL by ensuring the anatomometric
placement of the femoral attachment site and
allowing for fine adjustments to graft length.
First, two Morphix ® Suture Anchors are seated
in the proximal two-thirds of the medial patellar
margin, establishing the patellar fixation sites.
The more sensitive femoral attachment site is
determined by anatomometric testing. The
doubled end of a semitendinosus autograft or
allograft is fixated within the femoral bone
tunnel. The unique, nonrotational deployment
of the Eclipse Soft Tissue Anchor preserves
the surgeon-desired precise orientation of the
graft within the bone tunnel. Finally, the two
ends of the graft are secured at length by the
suture anchors in the patella, allowing for final
fine adjustments to graft length.
L ATERAL P ATELLOFEMORAL I NSTABILITY AND
THE M EDIAL P ATELLOFEMORAL C OMPLEX