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In studies on lateral traction that we conducted
in order to determine the best fixation position
for MPFL reconstruction using the patellar
tendon, we found that although the ligament
was not isometric, the best fixation position
was at 60 degrees of flexion, at which there was
less lateralization of the patella.
Clinical experience
Non-randomized study
After gaining anatomical knowledge on the
MPFL, we moved on to study the evolution of
patients with acute patellofemoral dislocation.
In a non-randomized manner, we analyzed the
evolution of 16 patients who had been treated
conservatively and 17 who had been treated
surgically [5]. The study was conducted in a
public hospital, among patients of low social
condition, which caused follow-up difficulties,
especially among the patients who had been
treated conservatively.
Conservative treatment
This treatment was provided for 16 patients
who had been radiographically examined in
anteroposterior, lateral and axial patellar views.
These radiographs allowed us to investigate
the presence of factors that might predispose
these patients to patellofemoral instability. In
accordance with Dejour
et al.
[6], we took into
consideration three predisposing factors: flat
trochlea on lateral or axial x-rays and high
patella on lateral X-rays. In this group,
14 patients had at least one predisposing factor.
The conservative treatment was administered
in the following manner:
1)
Aspiration of hemarthrosis when present
and voluminous
2)
Immobilization for three weeks
3)
Rehabilitation program until movement and
muscle strength had been recovered
The results showed that after a minimum
follow-up of 26 months (mean of 36.5), we had
eight patients with recurrent episodes of
dislocation and six patients with complaints of
some degree of instability.
Surgical treatment
The surgical treatment was administered to
17 patients. All these patients underwent
magnetic resonance imaging (MRI) in order to
diagnose the lesion. We analyzed the MRI and
decided whether the lesion was in the patella or
in the femur. This decision was made by one of
the surgeons.
Nine patients had a MPFL at the patellar
insertion. In these cases, the ligament was
repaired by reinserting the ligament in the
patella by means of direct suturing or under
arthroscopic viewing (fig. 2).
In seven patients, the avulsion of the MPFL
was interpreted as if it was in the femur, and the
ligament was reinserted using anchors.
The results showed that there were no episodes
of dislocation, but three patients reported
instability with symptoms of subluxation, in
the group in which the MPFL had been
reinserted into the femur.
Fig. 1 : Medial patellofemoral ligament deinserted
from the femur while maintained in its patellar
insertion.