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This chapter discusses when lateral-sided
surgery is necessary to perform concomitant
with a Medial Patellofemoral ligament (MPFL)
reconstruction. Specifically, when does one
need a lateral retinacular release/lengthening as
part of the surgical stabilization for the patella
to prevent recurrent lateral dislocations? In
order to answer this one needs to review “lateral
patella tilt”.
If one looks at the historic roots of patella
instability, the majority of early surgical
procedures favored increasing the directional
pullofmedial-sidedstructureswhileeliminating
or diminishing the pull of (abnormal) lateral-
sided forces (i.e.) a lateral retinacular release
[1, 2, 3].
Campbell’s Operative Orthopaedics
(1980), in reviewing surgical procedures for
patella instability, reported that procedures
used to surgically correct lateral patella
dislocations that have been the most widely
used and the most successful included “release
of tight and contracted soft tissues, including
the vastus lateralis tendon, to remove deforming
forces” [4].
Patella position in the sagittal view has been
analyzed and measured since late 1930’s when
Blumensaat recognized patella position and its
relationship to patella dislocation [5].
Patella tilt, however, began to be analyzed and
measured with the introduction of radiographic
axial imaging. The addition of axial slicing
afforded by CT scans and later MR imaging
added to the recognition and evaluation of this
anatomic feature. The position of the patella in
relation to the trochlear groove was a primary
component of “patella malalignment.”
H. Dejour and G. Walch, leading a combined
effort with the entire “Lyonnaise” team,
analysed over 1800 radiographic cases of
patellofemoral (PF) patients and controls. This
analysis utilized precise radiographic review of
the trochlea on lateral view radiographs with a
strict superposition of both posterior femoral
condyles, and a standardised CT protocol.
Within this body of work the Lyonnais team
defined principle imaging factors associated
with lateral patella dislocations (objective
instability). The authors defined lateral patella
tilt by overlapping CT images comparing the
long axis of the patella to the posterior femoral
condylar line. A lateral patella tilt >20° was the
threshold value associated with objective
patella instability [6]. Excessive lateral patella
tilt was included as a correctable risk factor in
the “le menu à la carte”. An early hypothesis of
the etiology of lateral patella tilt was one of
muscle weakness, specifically VMO dysplasia.
Lateral-Sided Surgerywith
MPFL Reconstruction:
When is this needed?
E.A. Arendt