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Double level osteotomy for genu varum deformity
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phone, and the radiological results were
assessed by plain radiographs and standing
long leg X-Rays between 3 and 6 months
postoperatively.
Results
We had no complication in this series but one
case of recurrence of the deformity related to
an impaction of the femoral osteotomy on the
medial side (heavy patient). 2 patients were
lost to follow-up after removing of the plates
(24 months) but were included in the results
because the file was complete at that date. All
the patients were assessed at a mean follow-up
of 46 ± 27 months (12-108).
The mean Lyshölm-Tegner score was 83.3 ±
7.5 points (62-91) and the mean KOOS score
was 95.1 ± 3.2 points (89-100). 40 patients
were satisfied [22] or very satisfied [18] of the
result. Only 2 were poorly satisfied.
Regarding the radiological results, if we
exclude the patient who had a loss of correction
not related to navigation, the goals were
reached in 39 cases (92.7%) for the HKA angle
and in 36 cases (88.1%) for the MPTMA with
only one case at 93°. The mean angles were:
181.83° ± 1.80° (177°-185°) for HKA, 89.71°
± 1.72° (85°-93°) for MPTMA and 92.76° ±
2.02° (89°-97°) for MDFMA.
At that mid-term follow-up no patient had
revision to a total knee arthroplasty.
Discussion
Combined distal femoral and proximal tibial
osteotomy in the treatment of genu varum is
technically difficult. Little has been said about
this technique in the literature and we could
find only one paper reporting on it [1]. It seems
that this technique was first described by
Benjamin [2] in 1969 for the treatment of
rheumatoid arthritis of the knee, but at the time,
he did not mention any HKA angle or joint line
obliquity. In their paper Babis
et al.
[1] reported
on 24 patients (29 knees) operated on with a
conventional technique (two closing wedge
osteotomies). The mean preoperative HKA
angle was 193.3° (that is 13.3° of varus) and
they used a computer-aided analysis of the
mechanical status of the knee for preoperative
planning. This was limited to preoperative
evaluation, and the reliabilityof the preoperative
radiographic evaluation was not assessed. The
results showed a mean postoperative HKA
angle of 176.9° (169.4° to 184.9°). They had a
residual varus in 2 cases (4.6° and 4.9°) and an
over correction of more than 4° in 10 cases and
more than 6° in 5. One knows that an under
correction may lead to failure of the operative
procedure and a too much overcorrection to
cosmetic discomfort.
The difficulty of the technique comes from the
fact that once the first osteotomy is performed,
wether femoral or tibial, landmarks change and
the ability to achieve a satisfactory alignment
with the second osteotomy becomes challenging
in the absence of reliable intra-operative
landmarks. Martres
et al.
[12] suggested
performing this operation in two different
stages to improve its accuracy and
reproducibility. It is also justified to consider
that complication occuring at both osteotomy
sites could lead to disastrous result. In our
series we had no non-union and only one mal-
union related to a secondary medial impaction
of the femoral osteotomy in an heavy patient.
Currently, we use a locking plate in spite of an
AO T-plate, which could avoid this
complication. On the other hand, every surgeon
operating osteoarthritic knees should be aware
of the risk of mal-union in the proximal tibia,
for a procedure that is often considered
temporary. In fact every osteotomy in a young
adult is susceptible to lead subsequently to a
TKR, and thus it is essential to plan ahead for
the iterative surgery called revision.
Computer-assistance allows controlling the
femoro-tibial axis (HKA angle) at every step of
the procedure and thus makes it more accurate.
Our current results are not far from a previous
preliminary series [22] and argue in favor of a
high reproducibility of this procedure. On a
clinical point of view the mean Lyshölm-
Tegner score improved from 41.2 ± 8.9 points