193 / 460
P.G. Ntagiopoulos, P. Byn, D. Dejour
192
32.5% grade IV. Trochleoplasty was combined
with an additional operation in all cases: MPFL
reconstruction in 16.1% of the cases (n=5),
VMO plasty 83.8% (n=26), tibial tuberosity
distalization 51.6% (n=16), tibial tuberosity
medialization 67.7% (n=21), lateral release
67.6% (n=21) (Table 1). Sulcus angle decreased
significantly (p<.01) from 152°±16° pre-
operatively to 141°±8° post-operatively, TT-TG
distance decreased significantly (p<.001) from
19±4mm to 12±5mm and patellar tilt without
quadriceps contraction decreased significantly
(p<.001) from 37°±7° to 15°±8° (Table 3).
Post-operative pain decreased in 77.4% of the
cases, remained unchanged or increased at
22.6% and there was no case of stiffness.
Apprehension sign remained positive in 19.3%
of the cases, patellar tracking was normal in all
cases, lateral patellar glide test was negative in
96.8% (<1 quadrant in 70%, <2 quadrants in
26.8%) and in 3.2% the quadrant test was 4/4
but with no patellar dislocation. Mean pre-
operative IKDC score was 51.2±22.9 (25-80)
and post-operative IKDC score was 82.5±17.9
(40-100), (p<.001). Therewas no radiographical
evidence of patellofemoral arthritis according
to Iwano criteria at the last follow-up. Eighty-
seven per cent of the patients returned to their
previous activities. There was no case with
patella dislocation recurrence and no residual
feeling of patellar instability and 93.6% replied
they were satisfied from surgery. Three
complicated cases were recorded: 2 cases of
hardware (staples) breakage that had to be
removed and one case of deep venous
thrombosis that was treated accordingly.
Discussion
The mid-term clinical, radiological and
functional results from the Lyon’s sulcus-
deepening trochleoplasty in the appropriate
patient population for the treatment of recurrent
patellar dislocation with underlying high-grade
trochlear dysplasia are satisfactory without
major complications and no sign of patello
femoral arthritis.
The authors’ approach to the treatment of
patients with recurrent patellar instability is
based on the following algorithm for the
identification of the major anatomic and
etiologic factors (fig. 2) [2, 14, 22, 24, 25]: the
presence of an excessive TT-TG distance more
than 20mm is considered abnormal and should
be treated with medialization osteotomy of the
tuberosity. Patella alta is another significant
factor contributing to patellar instability, and
its surgical treatment involves distalization
osteotomy of the tuberosity. An increased
lateral patellar tilt over 20° is amenable to
correction with lateral retinaculum release,
VMO plasty or reconstruction of the MPFL.
The presence of high-grade trochlear dysplasia
requires a type of trochleoplasty for its
correction [2, 18].
After the identification of any of the above
anatomic parameters, the patient must be
assessed for the presence and occurrence of
patellar dislocation.
1)
Patients with no history
of patella dislocation and pain as the only
symptom, and
2)
patients with patellofemoral
pain and with the presence of any of these
anomalies but no history of patellar dislocation,
are treated conservatively.
3)
Patients with any
of these anatomic anomalies and recurrent
patellar dislocation are candidates for surgery
after at least 3 true episodes of patellar
dislocation [14]. Surgical treatment of these
patients involves the correction of one or more
of the above-mentioned anatomic anomalies in
one stage, which often requires the combination
of more than one procedure. The presence of
high-grade trochlear dysplasia (i.e. B or D) in
these patients requires a deepening trochleo
plasty procedure for its correction. The goal of
sulcus-deepening trochleoplasty is to reshape
the trochlea, but patellar instability may be also
caused by the presence of co-existent anatomic
factors that must be addressed (e.g. tuberosity
osteotomy for patella alta or increased TT-TG
distance) and its treatment almost always
requires a combined soft-tissue procedure like
MPFL reconstruction or VMO plasty [14, 18].
The rationale of sulcus-deepening trochleo
plasty has three key elements: First, in cases of
a flat trochlea, it reshapes the trochlea back to a
more anatomic and concave geometry by
deepening the proximal sulcus, so that it engages