Question: In patients having high tibial osteotomy, how do lateral
closing-wedge and medial opening-wedge techniques compare with regard to
achievement and maintenance of correction?
Design: Randomized (allocation
concealed)*, unblinded,
controlled trial with 1-year follow-up.
Information provided by author.
Setting: A university medical center in Rotterdam, The
Netherlands.
Patients: 92 patients (mean age 50 y, 64% men) with radiographic
evidence of medial compartment osteoarthritis of the knee with medial joint
pain and varus malalignment. Patients with symptomatic osteoarthritis of the
lateral compartment, rheumatoid arthritis, range of movement of <100°,
grade-3 collateral ligament laxity, history of fracture or previous open
operation of the lower limb, or a flexion contracture of >10° were
excluded. Patients in whom both knees were symptomatic had only the first knee
included. 91 patients (99%) completed the study.
Intervention: 47 patients were allocated to closing-wedge high
tibial osteotomy and a plaster cylinder cast for 6 weeks after surgery, and 45
patients were allocated to opening-wedge osteotomy fixed with use of a Puddu
plate (Arthrex, Naples, Florida). The closing-wedge technique was performed
with use of the Allopro (Zimmer, Winterthur, Switzerland) calibrated osteotomy
guide to resect the bone. The common peroneal nerve was exposed and retracted,
and the anterior part of the fibular head was resected. The osteotomy was
fixed with 2 staples. A fasciotomy of the anterior compartment was done to
prevent compartment syndrome. For the opening-wedge technique, the extent of
the opening wedge was calculated preoperatively with use of the goniometric
formula table in the Arthrex instruction manual. During the procedure, the
degree of correction was controlled by fluoroscopic assistance. If the
opening-wedge was >7.5 mm, the open gap was filled with bone harvested from
the ipsilateral iliac crest. Patients in the opening-wedge group were also
randomized to receive a plaster cast (n = 22) or no cast (n = 23) after the
osteotomy.
Main outcome measures: Achievement of an overcorrection of the
hip-knee-ankle angle by 4° of valgus (difference between the achieved
valgus correction and the objective of 4° of overcorrection). A
dichotomous outcome of the proportion of patients achieving a valgus alignment
between 0° and 6° was also measured. Secondary outcomes were measures
of pain (visual analog scale [VAS]), walking distance, and knee function
(Hospital for Special Surgery [HSS] score). The HSS score measured pain,
function, range of movement, muscle strength, flexion deformity, and
instability and involved a questionnaire and a physical examination.
Main results: Analysis was by intention to treat. At 1 year, the
hip-knee-ankle angle was greater in the closing-wedge group than in the
opening-wedge group (3.4° vs 1.3°, respectively, with an adjusted mean
difference of 2.12° [95% confidence interval, 0.38 to 3.86]). The mean
deviation from valgus alignment of 4° was less in the closing-wedge group
than in the opening-wedge group (2.7° vs 4°, respectively, with an
adjusted mean difference of 1.67° [95% confidence interval, 0.42 to
2.92]). A valgus alignment within 0° to 6° was achieved in more
patients in the closing-wedge group than in the opening-wedge group (Table).
There was no difference between the closing-wedge and opening-wedge groups for
measurements of pain (mean decrease in VAS score, 2.3 vs 2.7 points,
respectively; p = 0.93), walking distance (mean increase, 1.7 vs 2.2 km,
respectively; p = 0.65), or knee function (mean increase in HSS score, 8.5 vs
9.4 points, respectively; p = 0.78). Within the opening-wedge group, the cast
and no-cast groups did not differ with regard to primary or secondary outcome
measures.
Conclusion: In patients who underwent high tibial osteotomy, the
lateral closing-wedge technique achieved more accurate correction with less
deviation from a 4° valgus overcorrection than the medial opening-wedge
technique.
The study by Brouwer and colleagues compared opening-wedge with
closing-wedge high tibial osteotomy in the treatment of medial compartment
osteoarthritis. It was not the intention in this study to determine the role
of osteotomy in the treatment of knee arthritis or to address the indications
for high tibial osteotomy compared with unicompartmental knee
arthroplasty.
Patients presented with a uniform clinical problem, and the surgery was
performed by the same group of surgeons. Patients were randomized
appropriately, and the treatment was carried out by protocol. Overcorrection
into valgus is desired in high tibial osteotomy for medial compartment
arthritis, both to improve patient outcome and to prevent recurrence of
deformity. In this study, even though closing-wedge high tibial osteotomy was
more effective in achieving the desired 4° of valgus overcorrection, there
was no difference between the 2 groups in terms of pain, walking distance, or
knee function.
Three patients in the opening-wedge group required repeat osteotomy because
of recurrent varus alignment, and 1 patient in the closing-wedge group
required a corrective varus osteotomy because of overcorrection. In the
opening-wedge group, more patients required the plate to be removed, 33
patients (73%) required bone-grafting, 8 patients reported persistent donor
site pain, and 2 patients progressed to nonunion of the osteotomy.
In conclusion, the use of closing-wedge osteotomy by this particular group
of surgeons achieved a more consistent degree of overcorrection with a lower
complication rate than did the use of opening-wedge osteotomy. Furthermore, 6
weeks of immobilization of the operated knee after surgery did not have a
deleterious outcome on either primary or secondary measures.