Archives of Orthopaedic and Trauma Surgery (2018) 138:307–316
Comparison of the outcome between unilateral and bilateral open
wedge high tibial osteotomy in the bilateral varus knees
· Ohsang Kwon
· Yong Seuk Lee
Received: 26 May 2017 / Published online: 29 November 2017
© Springer-Verlag GmbH Germany, part of Springer Nature 2017
Introduction Bilateral open wedge high tibial osteotomy (OWHTO) can be performed in a staged manner to enable the
healing and rehabilitation of each limb separately after surgery. However, the eﬀects of staged bilateral OWHTO on the pat-
tern of recovery and changes over time for each limb have not been established. Additionally, there is a lack of information
regarding the optimal timing for staged surgery.
Methods Twenty-two patients (44 knees) in the bilateral OWHTO group and 42 patients (42 knees) in the unilateral OWHTO
group were analyzed. Clinical and radiological results were evaluated and compared between the two groups. For the align-
ment change assessment, the hip–knee–ankle (HKA) angle and weight-bearing line (WBL) ratio were measured preopera-
tively and at postoperative 6 weeks, 3 months, 6 months, and 1 year.
Results The correction loss of HKA angle in the bilateral OWHTO group was signiﬁcantly larger than that in the unilateral
OWHTO group (0.5° ± 1.4° vs 1.3° ± 2.0°, p = 0.049). The correction loss of WBL ratio was signiﬁcantly greater in the
patients with staged bilateral OWHTO within a 3-month interval compared to those with staged bilateral OWHTO in an
interval longer than 3 months (WBL ratio; 7.5% vs 2.1%, p = 0.01). There was no signiﬁcant diﬀerence in the clinical scores
and range of motion at the last follow-up.
Conclusion The smaller loss of correction in the unilateral OWHTO group occurred compared to the bilateral OWHTO
group. Additionally, surgeons should keep in mind that the amount of correction loss may be greater if staged bilateral
OWHTO is performed at intervals of 3 months or less.
Keywords Knee · Osteoarthritis · Varus · Open wedge high tibial osteotomy · Unilateral · Bilateral · Outcome
Varus alignment of the lower extremities and associated
higher loads on the medial compartment of the tibiofemoral
joint during weight-bearing are signiﬁcant and potentially
modiﬁable biomechanical risk factors for osteoarthritis [1,
12, 18, 19]. Therefore, open wedge high tibial osteotomy
(OWHTO) is generally accepted as one of the most useful
surgical procedures for treating medial compartment osteo-
arthritis of the knee. By changing the knee alignment from
varus to valgus, excessive medial load is shifted to the lateral
compartment, which incurs less degenerative change of
medial compartment [1, 9]. However, when an OWHTO is
performed, the patient could be dissatisﬁed with unexpected
residual pain and symptoms for various reasons compared
with other surgical treatment options for medial compart-
ment osteoarthritis .
Interestingly, varus alignment is often bilateral and it may
be ideal to perform alignment correction on both limbs [10,
19]. However, some patients may not undergo the second
stage operation due to absence of symptoms, dissatisfaction
with the ﬁrst operation, unmet expectations, complications,
or other morbidities such as total knee arthroplasty (TKA)
[2, 17]. In this situation, patients may show asymmetry
between two limbs because mean leg length has increased
and the coronal alignment in the operated limb has shifted.
This can lead to clinical problems such as back pain, gait
disturbance, or loss of the correction [4, 5, 13].
* Yong Seuk Lee
Department of Orthopaedic Surgery, Seoul National
University College of Medicine, Seoul National University
Bundang Hospital, 166 Gumi-ro, Bundang-gu, Seongnam-si,
Gyeonggi-do 463-707, South Korea