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Deepening Trochleoplasty: the Lyon Procedure
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Complications
Complications include trochlear necrosis,
cartilage damage, incongruence with the
patella, and hypo or hypercorrection. Trochlear
necrosis seems not to occur, since the cartilage
nutrition is not dependent on the underlying
bone. Schottle [3] performed biopsies in three
patients after trochleoplasty, showing cartilage
cell viability and flap healing. He concluded
that the risk of cartilage damage is low.
Incongruence with the patella is another
possible complication, especially because
patellar dysplasia is common in this population,
but the long term outcomes are not known.
Hypo or hypercorrection, along with missed
associated abnormalities may cause failure of
the procedure.
Results
Trochleoplasty results are generally good in
terms of stability and function, while the results
for pain are less clear.
Fucentese
et al.
[4], using CT scans pre and
post-operatively, demonstrated that trochleo
plasty lateralized the trochlear groove and
medialized the patella, increased the trochlear
depth, decreased the lateral patellar inclination
angle, decreased the sulcus angle and increased
the lateral trochlear slope, thus recreating a
more normal anatomy. Amis
et al.
[5] studied
the patellar tracking in normal knees, after
simulating dysplasia and again after performing
a trochleoplasty and concluded that trochleo
plasty increased stability and provided small
but significant changes in patellar tracking.
Two series reviewing clinically deepening
trochleoplasty were published in the
“10
e
Journées Lyonnaises de Chirurgie du Genou”
in 2002: The first group included 18 patients
who had failed patellar surgery for instability,
with a mean age of 24 years at surgery. The
mean follow up was 6 years (2 to 8 years, no
patients lost to follow up). The new surgery
was 6 times indicated for pain and 12 times for
recurrence of instability. The average number
of surgeries before the trochleoplasty was 2.
The deepening trochleoplasty was associated
to a tibial tubercle medialization in 8 patients,
in 6 to a tibial tubercle distalization and in 18 to
a
vastus medialis obliquus
advancement. All
patients were reviewed clinically with the
IKDC form and radiographically. Sixty five
percent were satisfied or very satisfied. The
knee stability was rated 13 times A and 5 times
B. Twenty eight percent of the patients had
residual pain, and this was correlated to the
cartilage status at surgery. Two patients
developed patellofemoral arthritis. The mean
patellar tiltwas 35° (18°-48°) in the preoperative
setting, and improved to 21°(11°-28°) with the
quadriceps relaxed and 24° (16°-32°) with the
quadriceps contracted after the surgery.
In the second group there were 44 patients.
They had no antecedents of patellofemoral
surgery. The mean follow up was 7 years (2 to
9 years). Twenty two tibial tubercle mediali
zations, 26 distalizations and 32 vastus medialis
obliquus advancements were associated at the
time of surgery. These patients were also
reviewed clinically with the IKDC form and
radiographically. Eighty five percent were
satisfied or very satisfied. The knee stability
was rated 31 times A and 13 times B. Five
percent had residual pain, but this was not
correlated to the cartilage status at surgery. No
patellofemoral arthritis was noted. The mean
patellar tilt preoperatively was 33 ° (24°-52°),
and improved postoperatively to 18° (9°-30°)
with the quadriceps relaxed and 22° (14°-34°)
with the quadriceps contracted.
Other authors also reviewed deepening
trochleoplasty. Verdonk
et al.
[6] described
13 procedures with a mean follow-up of
18 months. Patients were assessed using the
Larsen-Lauridsen score considering pain,
stiffness, crepitus, flexion and loss of function.
Seven patients scored poorly, three fairly and
three well. On a subjective scoring system,
however, six patients rated the result as very
good, four as good and one as satisfactory.
Only two patients found the result inadequate
and would never undergo the procedure again.
Thus, 77% were satisfied with the procedure.
Donnel
et al.
[7] described 15 patients
(17 knees) submitted to deepening trochleo
plasty with a mean follow-up of 3 years.