# Surgical strategy and complication management of osteotomy around the painful degenerative varus knee: ESSKA Formal Consensus Part II

Matthieu Ollivier, Steven Claes, Ahmed Mabrouk, David Elson, Alejandro Espejo-Reina, Vlad Predescu, Steffen Schröter, Ronald van Heerwarden, Jacques Menetrey, Philippe Beaufils, et al.

<figure><img src="image_1.png" /></figure>

## To cite this version:

Matthieu Ollivier, Steven Claes, Ahmed Mabrouk, David Elson, Alejandro Espejo-Reina, et al. Surgical strategy and complication management of osteotomy around the painful degenerative varus knee: ESSKA Formal Consensus Part II. Knee Surgery, Sports Traumatology, Arthroscopy, 2024, 32 (8), pp.2194-2205. 10.1002/ksa.12273. hal-04977120

HAL Id: hal-04977120

https://hal.science/hal-04977120v1

Submitted on 11 Mar 2025

HAL is a multi-disciplinary open access
archive for the deposit and dissemination of sci-
entific research documents, whether they are pub-
lished or not. The documents may come from
teaching and research institutions in France or
abroad, or from public or private research centers.

L'archive ouverte pluridisciplinaire HAL, est
destinée au dépôt et à la diffusion de documents
scientifiques de niveau recherche, publiés ou non,
émanant des établissements d'enseignement et de
recherche français ou étrangers, des laboratoires
publics ou privés.

<figure><img src="image_2.png" /></figure>

Distributed under a Creative Commons Attribution 4.0 International License
# Surgical strategy and complication management of osteotomy around the painful degenerative varus knee: ESSKA Formal Consensus Part II

Matthieu Ollivier<fnref n="1" />,<fnref n="2" /> ID | Steven Claes<fnref n="3" /> | Ahmed Mabrouk<fnref n="4" /> ID | David Elson<fnref n="5" /> |
Alejandro Espejo-Reina<fnref n="6" /> | Vlad Predescu<fnref n="7" /> | Steffen Schröter<fnref n="8" /> |
Ronald Van heerwarden<fnref n="9" /> | Jacques Menetrey<fnref n="10" /> | Philippe Beaufils<fnref n="11" /> |
Roman Seil<fnref n="12" /> | Roland Beker¹³ | Raghbir Khakha¹⁴ | Matthew Dawson¹⁵

## Abstract

**Purpose:** The purpose of the European consensus was to provide recommendations for the treatment of patients with a painful degenerative varus knee using a joint preservation approach. Part II focused on surgery, rehabilitation and complications after tibial or femoral correction osteotomy.

**Methods:** Ninety-four orthopaedic surgeons from 24 countries across Europe were involved in the consensus, which focused on osteotomies around the knee. The consensus was performed according to the European Society for Sports Traumatology, Knee Surgery and Arthroscopy consensus methodology. The steering group designed the questions and prepared the statements based on the experience of the experts and the evidence of the literature. The statements were evaluated by the ratings of the peer-review groups before a final consensus was released.

**Results:** The ideal hinge position for medial opening wedge high tibial osteotomy (MOW HTO) should be at the upper level of the proximal tibiofibular joint, and for lateral closing wedge distal femoral osteotomy (LCW DFO) just above the medial femoral condyle. Hinge protection is not mandatory. Biplanar osteotomy cuts provide more stability and quicker bony union for both MOW HTO and LCW DFO and are especially recommended for the latter. Osteotomy gap filling is not mandatory, unless structural augmentation for stability is required. Patient-specific instrumentation should be reserved for complex cases by experienced hands. Early full weight-bearing can be adopted after osteotomy, regardless of the technique. However, extra caution should be exercised in DFO patients. Osteotomy patients should return to sports within 6 months.

**Conclusion:** Clear recommendations for surgical strategy, rehabilitation and complications of knee osteotomies for the painful degenerative varus knee were demonstrated. In Part 2 of the consensus, high levels of

<footnote n="1">¹CNRS, ISM, Aix Marseille University, Marseille, France</footnote>

<footnote n="2">²Department of Orthopaedics and Traumatology, APHM, CNRS, ISM, Sainte-Marguerite Hospital, Institute for Locomotion, Aix Marseille University, Marseille, France</footnote>

<footnote n="3">³Department of Orthopedic Surgery, AZ Herentals Hospital, Herentals, Belgium</footnote>

<footnote n="4">⁴Department of Trauma and Orthopaedics, Leeds Teaching Hospitals, England, UK</footnote>

<footnote n="5">⁵Department of Orthopaedics, Queen Elizabeth Hospital, Gateshead, UK</footnote>

<footnote n="6">⁶Hospital Vithas Málaga, Málaga, Spain</footnote>

<footnote n="7">⁷Department of Orthopedics and Traumatology, St Pantelimon Clinical Hospital Bucharest, University of Medicine and Pharmacy 'Carol Davila', Bucharest, Romania</footnote>

<footnote n="8">⁸Department of Traumatology and Reconstructive Surgery, BG Trauma Center Tübingen, Tübingen, Germany</footnote>

<footnote n="9">⁹Centre for Deformity Correction and Joint Preserving Surgery, Kliniek ViaSana, Mill, The Netherlands</footnote>

<footnote n="10">¹⁰Orthopaedic Surgery Service, University Hospital of Geneva, Geneva, Switzerland</footnote>

<footnote n="11">¹¹Department of Orthopaedics and Traumatology, Centre Hospitalier de Versailles, Le Chesnay, France</footnote>

<footnote n="12">¹²Department of Orthopaedic Surgery, Centre Hospitalier Luxembourg-Clinique d'Eich, Luxembourg, Luxembourg</footnote>
**Correspondence**

Matthieu Ollivier, Aix Marseille University, CNRS, ISM, 13009 Marseille, France.

Email: Ollivier.mt@gmail.com

**Funding information**

None

agreement were reached by experts throughout Europe, under variable working conditions. Where science is limited, the collated expertise of the collaborators aimed at providing guidance for orthopaedic surgeons developing an interest in the field and highlighting areas for potential future research.

**Level of Evidence:** Level II, consensus.

**KEYWORDS**

complications, knee osteotomy, rehabilitation, surgical strategy, varus knee

# INTRODUCTION

Osteotomy has become increasingly popular over the last 20 years after a significant decline in the preceding two decades [60]. The most frequently performed surgery is varus correction at the proximal tibia where both open and closed wedge osteotomy are frequently employed. While open wedge osteotomy creates a gap which is either filled with bone or bone substitutes or left unfilled, closed wedge osteotomy guarantees direct bony contact and more primary healing. However, the subject remains controversial. New angle stable plates offer early mobilisation under full weight bearing irrespective of technique. Four registries from Finland, Sweden, the United Kingdom and Australia are currently established [38]. The survival rate after 5, 10 and 15 years of follow-up ranged in different studies between 86%–100%, 64%–97.6% and 44%–93.2%, respectively [12, 30, 40].

When comparing high tibial osteotomy (HTO) with unicompartmental knee arthroplasty (UKA), superior midterm survival was reported for HTO in a population under the age of 70 years [15]. A meta-analysis also showed that total knee arthroplasty after HTO performs better than after UKA in terms of knee score, revision rate and usage of revision implants [13, 51]. No difference was found in postoperative complication rates or incidence of infection between the two groups. Osteotomy seems to be a valuable biological option in unicompartmental medial osteoarthritis.

Computer-assisted surgery may help to improve accuracy and reproducibility in osteotomy [48].

Part II focuses on surgical strategy, rehabilitation and complications associated with performing osteotomy in the painful varus degenerative knee.

# MATERIALS AND METHODS

The European Society for Sports Traumatology, Knee Surgery and Arthroscopy (ESSKA) European osteotomy consensus process was initiated in April 2020. The

methodology has been described in detail in the publication of Part 1 of the consensus. The process is summarised in Figure 1. Briefly, a total of 94 European surgeons and scientists were involved in the process comprising the steering (17 experts), rating (26 experts) and peer review group (51 orthopaedic surgeons). The questions group of steering group designed 37 questions which are divided into five sections: indications, planning, surgical strategy, rehabilitation and complications. A literature group, comprising the remaining members of the steering group, performed a literature search between June 2000 and December 2020 including PubMed, Google Scholar, and EMBASE according to keywords relevant to each specific question. Peer-reviewed clinical studies with levels of evidence ranging from 1 to 5 were included in this analysis. Only papers published in English were considered. The two groups at first worked independently to avoid any bias, and after the questions were defined, all members of the steering group were involved in answering these questions based on the literature and experts' experience.

Each question was designated based on its scientific level, that is, grade A, B, C or D.

A—high scientific level, B—scientific presumption, C—low scientific level and D—expert opinion.

The statements were rated by a group of 26 surgeons across the European countries. Each expert was asked to evaluate all pairings by using a 1- to 9-point Likert grading scale. Values of 2–8 represented possible intermediate situations. A proposal was deemed appropriate when the value of the median was ≥7, and the scores of each rater were ≥5.

The steering committee reviewed the results of two rounds of evaluation by the rating group and the statements were modified where needed.

The review group was composed of 51 European surgeons from around Europe who routinely manage patients with varus, painful and degenerative knees and regularly perform osteotomy. The group was specifically required to evaluate the recommendations in the final document for their relevance to a diverse

<footnote n="13">¹³Center of Orthopaedics and Traumatology, University Hospital Brandenburg an der Havel, Medical School Brandenburg, Brandenburg, Germany</footnote>

<footnote n="14">¹⁴Guys and St Thomas' Hospital, London, UK</footnote>

<footnote n="15">¹⁵North Cumbria University Hospital NHS Trust, North Cumbria, UK</footnote>
<figure><img src="image_3.png" /><figcaption>**FIGURE 1** Summary of the consensus workflow.</figcaption></figure>

European readership, together with their geographical adaptability and readability.

The entire project can also be read in more detail on the ESSKA website (http://www.esska.org/page/projects).

# RESULTS

## Section 3: Surgical strategy

(1) Is there an ideal position for the hinge in MOW HTO and lateral closing wedge (LCW) DFO?

The final hinge position for the MOW HTO should be in the region of the proximal third of or just above the fibular head. The initial K-wire placement to determine the final hinge position should be immediately above this level for the final osteotomy cut to be at the optimal level Figure 2. The hinge should be in a lateral position to avoid changes in the posterior tibial slope (PTS) **(Grade C)**.

The final hinge position for the LCW DFO should be located just above the level of the medial femoral condyle, adjacent to the downslope of the flare of the distal femur **(Grade D, Agreement 8.5 ± 1.9)**.

(2) Should the hinge be protected when doing an osteotomy?

Despite some technical notes supporting the use of a temporary hinge wire or screw in providing

<figure><img src="image_4.png" /><figcaption>**FIGURE 2** Anteroposterior fluoroscopic image of the left knee demonstrating the osteotomy wire ending at the level of the proximal third of the fibular head in the axial plane and to the level of the hinge wire in the coronal plane.</figcaption></figure>

additional protection, there is no clear evidence in the literature that the use of a hinge wire or screw is mandatory during osteotomy surgery **(Grade D, Agreement 7.9 ± 1.3/9)** (Figure 3).
<figure><img src="image_5.png" /><figcaption>**FIGURE 3** Anteroposterior fluoroscopic image of the left knee demonstrating a K wire placed as a protective measure for the hinge.</figcaption></figure>

(3) Is there an advantage of biplanar cut in MOW HTO and LCW DFO?

In general, the biplane osteotomy provides additional stability, a larger surface contact area for bony union and rotational control in the presence of a hinge fracture. A further benefit is derived from the avoidance of the patella tendon insertion during HTO (Grade C).

Despite the lack of strong clinical evidence and limited biomechanical studies, the recommendation is to use a biplanar cut in DFO for those learning the technique (Grade D, Agreement 8 ± 2/9).

(4) Should the technique be adjusted, based on the amount of correction required and the level of the deformity?

The steering group recommends preoperative planning in osteotomy surgery to determine the expected bony morphology after correction of the coronal alignment to determine the optimal technique and level of osteotomy for surgical correction (Grade B, Agreement 8.7 ± 0.5/9).

(5) How does the osteotomy technique (opening wedge vs. closing wedge) influence leg length?

When performing an opening wedge osteotomy (tibial or femoral), there may be a resultant increase in the leg length. Conversely, a closing wedge osteotomy (tibial or femoral) will tend to maintain an equal length. Although each case must be taken on its merits, there is no evidence to support any adverse effect on clinical outcomes for either technique. It is, therefore, reasonable to consider the pre-existing leg length discrepancy in the surgical strategy, and the appropriate selection of either an opening or a closing wedge should be undertaken accordingly (Grade A, Agreement 8.6 ± 0.8/9).

(6) Should the tibial osteotomy technique (opening wedge, closing wedge or the direction of

biplane cut) be modified in cases of patellofemoral disorders including patella baja?

The effects of various osteotomy techniques on patellofemoral disorders are the subject of ongoing discussion and further research is required in this area. There are no clinical studies to strongly influence any surgical technique in the presence of patellofemoral disorders. The effect of reducing patella height in medial opening wedge osteotomies and increasing the patella height in LCW osteotomies appears negligible for routine corrections and, therefore, should not influence surgical strategy for this indication (Grade B).

Pending results of further investigation and in large opening wedge corrections, a distal tuberosity osteotomy may be considered to prevent adverse effects on patella height and patellofemoral cartilage forces (Grade D, Agreement 8.4 ± 1/9).

(7) Is there an ideal fixation to be promoted for MOW HTO or LCW DFO?

The steering group recommends angle-stable locking plate fixators because they have been demonstrated to provide better clinical outcomes and reduce correction loss when compared to nonlocking plates. Long plate fixators are recommended in preference to short spacer plates as they have superior stability (Grade A, Agreement 8.7 ± 0.8/9).

(8) Should the gap be filled in MOW HTO?

The use of a graft to fill the osteotomy gap is not required for routine use in MOW HTO surgery. Where required, additional stability may be achieved with the use of structural void fillers. Ideally, a choice of void filler where required should be available to the surgeon. Autograft bone void fillers can increase the rate of bony union but may be associated with donor site morbidity. Allograft options provide a potential solution, especially in larger opening gaps, but availability is not universal due to regulatory restrictions in some countries. Synthetic void fillers may have an increased risk of nonunion and infection (Grade B, Agreement 8.6 ± 0.7/9) (Figure 4).

(9) What is the place for patient-specific instrumentation (PSI) in MOW HTO and LCW DFO.

The steering group recommends gaining experience with conventional techniques prior to adopting the use of PSI which may be a demanding technique. The adoption of PSI for basic MOW HTO or LCW DFO is recommended for experienced surgeons who require familiarisation before using the technique for more demanding cases. Nuanced presentations with the existence of multiplanar deformity (especially including elements such as torsion and intra-articular malunion) are ideal situations for the PSI in the hands of an experienced surgeon who has ascended the learning curve in this technique (Grade D, Agreement 8.4 ± 0.86/9).
<figure><img src="image_6.png" /><figcaption>**FIGURE 4** Anteroposterior bilateral long leg standing radiographs (a) preoperative demonstrating bilateral degenerative varus knee with medial mechanical axis deviation. (b) Postoperative bilateral medial opening wedge high tibial osteotomy with neutral mechanical axis.</figcaption></figure>

**Section 4: Rehabilitation**

(1) How soon can full weight-bearing commence in MOW HTO, LCW HTO/LCW DFO surgery?

Rehabilitation is the same after surgery in both MOW HTO and LCW HTO managed with plate fixators and is aimed at functional mobilisation and early full weight-bearing, provided the soft tissue healing is not compromised (**Grade B**).

The biomechanical situation is less stable in distal femoral osteotomy (DFO) compared to the HTO and therefore requires greater discretion with regard to weight-bearing. An LCW DFO, therefore, requires a more cautious approach to weight-bearing than HTO. The steering committee agrees to a period of restricted weight-bearing followed by

carefully monitored full weight-bearing (FWB) at 6/52 (**Grade C**).

An unstable configuration diagnosed either intraoperatively or postoperatively mandates a restriction of full weight-bearing and possible surgical augmentation of the fixation or both. This is further discussed in detail in the complications section (**Grade C, Agreement 8.4 ± 0.8/9**).

(2) When may patients return to work after osteotomy for the painful varus degenerative knee?

The steering committee recommends a discussion around the intensity of the patient's employment with attention to the specific physical demands of a job. Each case will have its individualised characteristics. Employment with low levels of physical stress may be compatible
with return in under 3 months but higher levels of physical burden are likely to exceed 3 months. Mental health must be factored in, but patients can generally be reassured that they are likely to return to the same or higher level of work after surgery (Grade C, Agreement 8.7 ± 0.6/9).

(3) When may patients return to sports (RTSs) after osteotomy for the painful varus degenerative knee?

Patients may be counselled that RTS is highly, likely after osteotomy provided that rehabilitation is completed. The majority can expect RTS within 6 months, especially those practising low-impact activities. Most of the patients will return to a higher level as compared to their preoperative period, however, patients are less likely to achieve an RTS at the level they enjoyed prior to the onset of symptoms (Grade C, Agreement 8.8 ± 0.5/9).

## Section 5: Complications

(1) What is the definition of a complication in osteotomy around the knee?

A complication following osteotomy surgery may be defined as a significant deviation from the normal course of events during surgery or postoperatively. Complications may be subdivided into those requiring no treatment or nonoperative treatment and those requiring surgical treatment, according to Martin et al [31]. Failure to cure is not in itself a complication and plate removal may be regarded as a normal consequence of surgery (Grade C, Agreement 8.8 ± 0.5/9). A list of the commonly reported complications based on timing in HTO is reported in Table 1.

(2) What routine measures aid in the prevention of soft tissue, nerve and vascular injury?

A meticulous surgical technique combined with the careful use of retractors is essential in preventing injury to the neurovascular structures posteriorly and the patella tendon anteriorly during all osteotomy surgery. During HTO, particular attention must be paid to the direction of the saw blade which after cutting the immediately visible cortical bone should be directed so that the long axis of the saw blade is angled at approximately 30°anteriorly to the posterior cortex in MOW HTO and 40° in LCW HTO. There is no scientifically proven evidence that knee flexion or extension protects the neurovascular bundle (Grade C, Agreement 8.4 ± 0.8/9).

(3) What is the definition of a hinge fracture and how should it be managed intraoperatively during MOW HTO?

Hinge fractures are propagations of the osteotomy plane to the opposite (lateral) tibial cortex or the tibial articular surface in the case of MOW HTO.

<table><caption>TABLE 1 Overview of different complications as a consequence of HTO found in literature.</caption><thead><tr><th>Timing</th><th>Complication</th></tr></thead><tbody><tr><td rowspan="5">Intraoperative</td><td>Hinge fracture</td></tr><tr><td>Slope alteration (increased PTS)</td></tr><tr><td>Changes in patellar height (patella baja)</td></tr><tr><td>Nerve injury</td></tr><tr><td>Vascular injury</td></tr><tr><td rowspan="4">Early postoperative</td><td>Infection</td></tr><tr><td>Thromboembolic (DVT-PE)</td></tr><tr><td>Compartment syndrome</td></tr><tr><td>Wound healing problems</td></tr><tr><td rowspan="4">Late postoperative</td><td>CRPS</td></tr><tr><td>Loss of correction/hardware failure</td></tr><tr><td>Delayed and nonunion</td></tr><tr><td>Hardware irritation</td></tr></tbody></table>

Abbreviations: CRPS, complex regional pain syndrome; DVT, deep venous thrombosis; HTO, high tibial osteotomy; PE, pulmonary embolism; PTS, posterior tibial slope.

These fractures have been classified by Takeuchi into types I, II and III [57]. A type I fracture is the continuation of the osteotomy to an exit point on the lateral cortex above or at the proximal tibia-fibular joint (PTFJ). A type II fracture exits at the inferior aspect or distal to the PTFJ. A type III fracture exits into the joint producing a lateral plateau fracture. All hinge fractures (especially type II and III) may become unstable. Any displacement discovered intraoperatively under scrutiny by image intensifier must be addressed by reduction and fixation. A type I fracture may be satisfactorily reduced, and the hinge compressed by the selected medial plate fixator, but displaced type II and III fractures will require reduction and interfragmentary screw or small additional lateral locking plate fixation in addition to the osteotomy plate. The type II fracture is fixed at the lateral side and the type III by interfragmentary screws introduced from the medial side. A pre-emptive hinge reinforcement screw may be deployed in ‘at-risk’ cases but the introduction of an apical drill hole does not reliably prevent hinge fractures especially in older patients and in larger corrections (Grade B, Agreement 8.4 ± 0.9/9).

Undisplaced type I hinge fractures may be managed by standard rehabilitation but undisplaced type II and III fractures should not be exposed to early postoperative full weight-bearing, especially if no additional fixation or gap filling has been applied. Displacement of any hinge fracture on either of a
minimum of two radiographic projections postoperatively should be considered for operative intervention. If the displacement is considered minor, an altered rehabilitation regime will be necessary until the osteotomy has united or is considered stable (Grade C, Agreement 8.4 ± 0.9/9).

(4) What is the management of hinge fractures diagnosed postoperatively?

Undisplaced type 1 hinge fractures may be managed by standard rehabilitation but undisplaced type 2 and 3 fractures should not be exposed to early postoperative full weight-bearing, especially if no additional fixation or gap filling has been applied. Displacement of any hinge fracture on either of a minimum of two radiographic projections postoperatively should be considered for operative intervention. If the displacement is considered minor, an altered rehabilitation regime will be necessary until the osteotomy has united or is considered stable (Grade C, Agreement 8.7 ± 0.8/9).

(5) In which situation is early interventional surgery indicated for loss of correction?

Loss of correction occurs in the case of MOW HTO where there is a measurable change in the MPTA, a displaced hinge fracture or a broken implant prior to bony union. The use of locking plates dramatically decreases the risk of postoperative loss of correction. The Interventional surgery for loss of correction should be gauged on a case-by-case basis. Determining the cause, degree and effects of failure will determine whether to treat conservatively or to revise the osteotomy (Grade C, Agreement 8.8 ± 0.5/9).

(6) What peri-operative antibiotic prophylaxis is appropriate?

Perioperative antibiotics are strongly recommended for routine use in osteotomy surgery. No standard regimen has been proven to be superior to any other. Osteotomy surgery should be accompanied by a standard antibiotic prophylaxis regime as would be used for knee arthroplasty in the hospital involved (Grade D, Agreement 8.9 ± 0.2/9).

(7) How is infection diagnosed and treated after osteotomy?

No diagnostic criteria exist to distinguish between superficial and deep infection which is specific to osteotomy. Because MOW HTO does not involve muscular or fascial coverage of the implant, any suspected osteotomy infection must be regarded as potentially requiring surgical intervention because of the proximity of the implant to the skin surface. The steering group recommends that antibiotics are not commenced before review by the surgical team. It is suggested the following algorithm (Figure 2) is used for diagnosis and treatment of infection (Grade C, Agreement 8.8 ± 0.5/9).

(8) How is aseptic nonunion diagnosed and treated after osteotomy?

Aseptic nonunion is a rare complication of MOW HTO even when performed without void filler. It is essential to combine clinical assessment with the radiological findings on a case-by-case basis. Obvious mechanical factors including loss of correction, hardware failure or lateral hinge fracture (LHF) may confirm the diagnosis and should direct surgical management. Close clinical follow-up is essential and a computed tomography scan may be helpful. Rosteius et al. [46] described a spectrum of four operative treatment strategies in their series. The following algorithm is proposed (Figure 2) for the diagnosis and treatment of aseptic non-union in MOW HTO (Grade C, Agreement 8.6 ± 0.7/9).

(9) Should metalware be removed after the bone union?

Removal of hardware after bone union is reasonable if it is deemed to be symptomatic to a significant degree or if arthroplasty is considered likely to become necessary. Consideration must, however, be made of the cost and risk of complications from a further surgical procedure. As such, hardware removal should not be considered as a routine procedure (Grade C, Agreement 8.7 ± 0.6/9).

## DISCUSSION

The most important finding in the present study is demonstrating an agreed and where applicable literature supported clear surgical strategy, rehabilitation measures and measures to mitigate the complications when performing tibial or femoral correction osteotomy for the painful degenerative varus knee.

The surgical procedure should be performed at the site of the deformity to unload the medial compartment by maintaining natural joint-line obliquity. Early weight bearing immediately after surgery is often allowed, due to advanced surgical techniques and the use of angle-stable plates for fixation. While complications do occur, they can be prevented and managed using the suggested algorithms (Figures 1 and 2).

HTO and DFO procedures are intricate, often leading to changes in limb length (LL), PTS, and patellar height (PH). These alterations have profound implications on biomechanics and functionality. Mathematical models have illuminated the specific resultant variations in LL from different tibial osteotomy techniques. Notably, LCW tibial osteotomy (LCWTO) generally leads to a reduction in LL, in contrast to medial opening wedge tibial osteotomy (MOWTO), which is associated with an increase in LL. This dichotomy is substantiated by different randomised
controlled studies, which provide empirical evidence of leg shortening in LCWTO and leg lengthening in MOWTO [26, 36].

Similarly, the biplane technique is renowned for augmenting rotational and anteroposterior stability during osteotomies as proven in a cadaveric study [42]. This research underscores the significant enhancement of stability in biplane osteotomy compared to plate fixation, attributed mainly to the increased volume and surface area. Such structural enhancements are instrumental in promoting successful bony unions, as corroborated by van Heerwaarden et al. [19]. Nonetheless, the ramifications of biplanar osteotomy on the patellofemoral joint remain controversial because of varied outcomes in studies [8, 14, 19, 55, 62]. Further examination into the influence of osteotomy techniques reveals a mixed picture regarding PH. While some studies noted changes post-MOW HTO

and LCW HTO, others, like the randomised controlled study by Nerhus et al. [37] did not. This narrative is echoed in the research conducted by others on distal biplane osteotomy in MOW HTO, which also found no discernible impact on PH [2, 9, 14, 37, 43, 62].

Regardless of the chosen strategy, angle-stable devices are pivotal in enabling early mobilisation, eliminating the need for plaster immobilisation. Radioisometric studies by Luites et al. challenged conventional opinions by showing that the TomoFix plate fixator gives comparable stability in OW and LCW HTO [28]. In a similar vein, empirical evidence suggests the superiority of long-locking plate fixation over spacer plates in preserving coronal correction and minimising complications [1]. It has been shown that significantly enhanced stability is provided using locking plates in MOW HTO equal to the stability of LCW HTO [24, 28, 35, 41, 50]. Despite these technological strides, the debate over the optimal choice between

<figure><img src="image_7.png" /><figcaption>**FIGURE 5** Algorithm summarising the ideal strategy to treat infection following knee osteotomy (high tibial osteotomy [HTO]).</figcaption></figure>
locking, nonlocking fixation and the ideal gap filler in
opening wedge osteotomies persists. Addressing this
knowledge gap, Lash et al. [27] conducted a comprehen-
sive systematic review of 3033 MOW HTO cases,
advising for the use of autografts in larger gaps and
affirming the safety of standard MOW HTO procedures
with smaller gaps without void fillers. A meta-analysis
further endorses the consideration of void fillers in cases
involving extensive corrections and hinge fractures [18].
Additionally, a systematic review of 1421 MOW HTO
cases concludes that the choice of gap filler does not
markedly affect union rates or correction loss, irrespective
of the filler type [54]. The authors noted a clear correlation
between gap size and healing duration, advising against
the use of synthetic void fillers in standard MOW HTO
procedures for smaller gaps [54].

Despite employing robust osteotomy techniques
and fixation methods, ensuring hinge integrity
remains paramount, especially considering its sig-
nificant influence on PTS. The precise hinge
placement is crucial, particularly when positioned
posterolaterally, due to its potential influence on the
PTS. A gamut of techniques, including the utilisation
of wires, anteroposterior drill holes, meticulous
osteotomy execution, and K-wire placement, are
recommended to mitigate the risk of hinge fractures
[5-7, 17, 21, 22, 29, 32-35, 39, 45, 59, 61].
Moreover, LHFs, a prevalent intraoperative compli-
cation of MOW HTO especially with larger wedge
sizes, necessitate proactive management to ensure
mechanical stability. This may entail the adoption of
bilateral plating, additional screw fixation or tailored
adjustments in weight-bearing protocols [44].

With a robustly protected hinge and appropriately
tailored fixation, patients can expect to bear full weight
immediately post-HTO and partially post-DFO and double-
level osteotomies. Typically, patients may resume their
preoperative work within 3 months and can engage in
recreational or sports activities after 6 months. Although
complications are an inherent risk, their prevention and
management can be effectively navigated using the
recommendations. (Figures 2 and 3).

Neurovascular complications are more serious and potentially more significant consequences. Tibial nerve injury was only reported once as a result of an extraprominent K-wire and lag screw through the posterolateral cortex [53]. More recently, deep peroneal nerve injury has been reported in MOW HTO due to lateral tibial cortex perforation distal to the osteotomy, with long wires or screws [20, 23]. Despite the absence of evidence-based recommendations to mitigate these risks, cautious surgical techniques should minimise these risks (Figure 5).

Popliteal and anterior tibial arteries are rarely injured
during HTO, however, multiple case reports exist in the
literature with both MOW HTO [3, 4, 11, 52] and LCW HTO
[16, 47, 49, 56, 58]. Kim et al. [25] demonstrated the
protective effect of placing a blunt retractor posterior to the

tibia and anterior to the popliteus muscle [25]. Choi et al. [10] described safety indices in the osteotomy plane to minimise the risk of vascular injury. Similarly, Kim et al. [25] demonstrated that saw blade angles greater than 30° to the coronal plane have a potential risk of injuring the neurovascular structures [25].

CONCLUSION

Clear recommendations for surgical strategy, rehabilitation
and complications of knee osteotomies for the painful
degenerative varus knee were demonstrated. In Part 2 of
the consensus, high levels of agreement were reached by
experts throughout Europe, under variable working condi-
tions. Where science is limited, the collated expertise of the
collaborators aimed at providing guidance for orthopaedic
surgeons developing an interest in the field and high-
lighting areas for potential future research.

AUTHOR CONTRIBUTIONS

Ahmed Mabrouk, David Elson, Steven Claes, Vlad Predescu, Raghbir Khakha and Alejandro Espejo-Reina wrote the initial consensus manuscript. Steffen Schröter and Ronald Van heerwarden edited the initial draft of the consensus. Jacques Menetrey, Roman Seil and Roland Beker reviewed the final consensus document. Philippe Beaufils created the methods behind the present consensus. Matthieu Ollivier and Matt Dawson chaired the consensus and wrote the final manuscript.

ACKNOWLEDGEMENTS

The authors would like to acknowledge the contribution of
those involved: Bogdan Ambroziv (Slovenia), Sandro
Fucentese (Switzerland), Kristian Kley (Germany), Dietrich
Pape (Luxembourg), Konrad Slynarski (Poland), Silvio
Villascusa) (Spain), Adrian Wilson (UK), Toon Claes, Stijn
Bartholomeeusen, Willem-Jan Vleugels, Wouter Van
Genechten (all Belgium), James Broderick (Ireland), Tamer
Sweed (UK), Cristian Fink (Austria), Alexander Benko
(Belarus), Peter Verdonk (Belgium), Vojtech Havlas
(Czech Republic), Lars Blond (Denmark), Jukka Ristiniemi,
(Finland), Jean Marie Fayard and Nicolas Graveleau (both
France), Michael Hantes (Greece), Michele Malavolta
and Roberto Rossi (both Italy), Romain Seil (Luxembourg),
Jacek Walawski and Pawel Walawski (both Poland), Levi
Reina Fernandes (Portugal), Stefan Mogos (Romania),
Leonid Solomon (Russia), Pablo Gelber and Pablo Crespo
(both Spain), Mats Brittberg (Sweden), Nevzat Reha
Tandogan) and Tahsin Beyzadeoglu (both Turkey), James
Robinson and Martyn Snow (both United Kingdom). Oleg
Eismont (Belarus), Geert Van Damme (Belgium), Semin
Becirbegovic (Bosnia), Peter Lavard, Kristoffer Weisskirch-
ner Barfod, Andreas Kappel (all Denmark), Paul-Sander
Vahi (Estonia), Mirouse Guillaume, Choufani Camille,
Morvan Antoine (all France), Matthias Feucht and Georg
Brandl (both Germany–Austria–Switzerland), Michael
losifidis and Athanasios Ververidis (both Greece), Andras
Tallay (Hungary), Mihai Vioreanu (Ireland), Francesco
Saccia, Kleber Garcia Parra, Alessio Maione, Davide
Bonasia (all Italy), Eriks Ozols (Latvia), Renaud Siboni
(Luxembourg), Nienke van Egmond, Reinoud Brouwer,
Robbert Gaasbeek (all Netherlands), Tor Kjetil Nerhus,
Arne Kristian Aune, Gilbert Moatsche (all Norway), Lukasz
Luboiński and Tomasz Pardała (both Poland), Manuel
Vieira da Silva, Helder Nogueira, Paulo Ribeiro de Oliveira
(all Portugal), Vlad Georgeanu, Radu Fleaca (both
Romania), Vadim Dubrov (Russia), Tomaz Malovrh
(Slovakia), Vicente López, José Silberberg, Tomas Roca,
Carlos Martin, Rafael Arriaza (all Spain), Mikael Östin, Karl
Eriksson, Anders Stålman (all Sweden), İrfan Esenkaya,
Elcil Kaya Bicer and Meriç Ünal (all Turkey). Also
acknowledgement of contribution by the ESSKA office
for organisational and administrative assistance through-
out and with special thanks for the fantastic dedication of
Anna Hansen Rak without whom this work would not have
been possible. The authors have no funding to report.

CONFLICT OF INTEREST STATEMENT

Matthew Dawson: Bodycad Consultant. Steven Claes: Arthrex Consultant. Raghbir Khakha: Newclip Consultant. Steffen Schroter: Newclip, and Synthes Consultant. Ronald Van heerwarden: Newclip Consultant. Jacques Menetrey: ESSKA past president. Philippe Beaufils: Consensus director. Roman Seil: ESSKA past president. Roland Beker: ESSKA. Matthieu Ollivier: Newclip, Arthrex and stryker Consultant. The remaining authors declare no conflict of interest.

DATA AVAILABILITY STATEMENT

All consensus data are available upon request.

ETHICS STATEMENT

The authors have nothing to report.

ORCID

Matthieu Ollivier https://orcid.org/0000-0002-6910-0873

Ahmed Mabrouk http://orcid.org/0000-0002-2547-3176

REFERENCES

1. Agarwala, S. & Shah, S. (2008) Staple versus locking compression plate fixation after lateral closing wedge high tibial osteotomy. *Journal of Orthopaedic Surgery, 16*(3), 303–307. Available from: https://doi.org/10.1177/230949900801600307

2. Amzallag, J., Pujol, N., Maqdes, A., Beaufils, P., Judet, T. & Catonne, Y. (2013) Patellar height modification after high tibial osteotomy by either medial opening-wedge or lateral closing-wedge osteotomies. *Knee Surgery, Sports Traumatology, Arthroscopy*, 21(1), 255–259. Available from: https://doi.org/10.1007/s00167-012-2304-z

3. Attinger, M.C., Behrend, H. & Jost, B. (2014) Complete rupture of the popliteal artery complicating high tibial osteotomy. *Journal of Orthopaedics*, 11(4), 192–196. Available from: https://doi.org/10.1016/j.jor.2014.08.002

4. Bartoli, M.A., Lerussi, G.B., Gulino, R., Schroeder, M. & Branchereau, A. (2010) False aneurysm at the origin of the anterior tibial artery after opening wedge osteotomy. *Vascular, 18*(1), 45–48. Available from: https://doi.org/10.2310/6670.2009.00042

5. van den Bekerom, M., Patt, T., Kleinhout, M., van der Vis, H. & Albers, G.H. (2010) Early complications after high tibial osteotomy: a comparison of two techniques. *Journal of Knee Surgery*, 21(1), 68–74. Available from: https://doi.org/10.1055/s-0030-1247797

6. Billings, A., Scott, D.F., Camargo, M.P. & Hofmann, A.A. (2000) High tibial osteotomy with a calibrated osteotomy guide, rigid internal fixation, and early motion. Long-term follow-up. *The Journal of Bone and Joint Surgery-American Volume*, 82(1), 70–79. Available from: https://doi.org/10.2106/00004623-200001000-00009

7. Boström, A., Amin, A.K., Macpherson, G.J., Pankaj, P. & Scott, C.E.H. (2021) Hinge location and apical drill holes in opening wedge high tibial osteotomy: a finite element analysis. *Journal of Orthopaedic Research*, 39(3), 628–636. Available from: https://doi.org/10.1002/jor.24704

8. Brinkman, J.-M., Lobenhoffer, P., Agneskirchner, J.D., Staubli, A.E., Wymenga, A.B. & van Heerwaarden, R.J. (2008) Osteotomies around the knee: patient selection, stability of fixation and bone healing in high tibial osteotomies. *The Journal of Bone and Joint Surgery. British Volume*, 90(12), 1548–1557. Available from: https://doi.org/10.1302/0301-620X.90B12.21198

9. Brouwer, R.W., Bierma-Zeinstra, S.M.A., van Koeveringe, A.J. & Verhaar, J.A.N. (2005) Patellar height and the inclination of the tibial plateau after high tibial osteotomy. The open versus the closed-wedge technique. *The Journal of Bone and Joint Surgery. British Volume*, 87(9), 1227–1232. Available from: https://doi.org/10.1302/0301-620X.87B9.15972

10. Choi, C.-H., Lee, W.-S., Jung, M., Moon, H.-S., Lee, Y.-H., Oh, J. et al. (2020) Adequate protection rather than knee flexion prevents popliteal vascular injury during high tibial osteotomy: analysis of three-dimensional knee models in relation to knee flexion and osteotomy techniques. *Knee Surgery, Sports Traumatology, Arthroscopy*, 28(5), 1425–1435. Available from: https://doi.org/10.1007/s00167-019-05515-1

11. Chun, K.C., So, B.J., Kang, H.T. & Chun, C.-H. (2018) Pseudoaneurysm formatlion due to popliteal artery injury caused by drilling during medial opening wedge high tibial osteotomy. *Knee Surgery and Related Research*, 30(4), 364–368. Available from: https://doi.org/10.5792/ksrr.18.039

12. Dal Fabbro, G., Grassi, A., Agostinone, P., Lucidi, G.A., Fajury, R., Ravindra, A. et al. (2024) High survivorship rate and good clinical outcomes after high tibial osteotomy in patients with radiological advanced medial knee osteoarthritis: a systematic review. *Archives of Orthopaedic and Trauma Surgery*. Available from: https://doi.org/10.1007/s00402-024-05254-0

13. El-Galaly, A., Nielsen, P.T., Jensen, S.L. & Kappel, A. (2018) Prior high tibial osteotomy does not affect the survival of total knee arthroplasties: results from the Danish Knee Arthroplasty Registry. *The Journal of Arthroplasty*, 33(7), 2131–2135.e1. Available from: https://doi.org/10.1016/j.arth.2018.02.076

14. Erquicia, J., Gelber, P.E., Perelli, S., Ibañez, F., Ibañez, M., Pelfort, X. et al. (2019) Biplane opening wedge high tibial osteotomy with a distal tuberosity osteotomy, radiological and clinical analysis with minimum follow-up of 2 years. *Journal of Experimental Orthopaedics*, 6(1), 10. Available from: https://doi.org/10.1186/s40634-019-0176-6

15. Fitoussi, A., Dartus, J., Erivan, R., Pasquier, G., Migaud, H., Putman, S. et al. (2023) Management of medial femorotibial osteoarthritis: epidemiology, and survival of unicompartmental knee arthroplasty versus valgus high tibial osteotomy in France. Study of 108,007 cases from the French National Hospitals Database. *Orthopaedics & Traumatology: Surgery & Research*, 109(8), 103692. Available from: https://doi.org/10.1016/j.otsr.2023.103692
16. Georgoulis, A.D., Makris, C.A., Papageorgiou, C.D., Moebius, U.G., Xenakis, T. & Soucacos, P.N. (1999) Nerve and vessel injuries during high tibial osteotomy combined with distal fibular osteotomy: a clinically relevant anatomic study. *Knee Surgery, Sports Traumatology, Arthroscopy*, 7(1), 15–19.
Available from: https://doi.org/10.1007/s001670050114

17. Gulagaci, F., Jacquet, C., Ehlinger, M., Sharma, A., Kley, K., Wilson, A. et al. (2020) A protective hinge wire, intersecting the osteotomy plane, can reduce the occurrence of perioperative hinge fractures in medial opening wedge osteotomy. *Knee Surgery, Sports Traumatology, Arthroscopy*, 28(10), 3173–3182. Available from: https://doi.org/10.1007/s00167-019-05806-7

18. Han, J.H., Kim, H.J., Song, J.G., Yang, J.H., Bhandare, N.N., Fernandez, A.R. et al. (2015) Is bone grafting necessary in opening wedge high tibial osteotomy? A meta-analysis of radiological outcomes. *Knee Surgery & Related Research*, 27(4), 207–220. Available from: https://doi.org/10.5792/ksrr.2015.27.4.207

19. van Heerwaarden, R., Najfeld, M., Brinkman, M., Seil, R., Madry, H. & Pape, D. (2013) Wedge volume and osteotomy surface depend on surgical technique for distal femoral osteotomy. *Knee Surgery, Sports Traumatology, Arthroscopy*, 21(1), 206–212. Available from: https://doi.org/10.1007/s00167-012-2127-y

20. Itou, J., Itoh, M., Maruki, C., Tajimi, T., So, T., Kuwashima, U. et al. (2020) Deep peroneal nerve has a potential risk of injury during open-wedge high tibial osteotomy. *Knee Surgery, Sports Traumatology, Arthroscopy*, 28(5), 1372–1379. Available from: https://doi.org/10.1007/s00167-019-05445-y

21. Jacobi, M., Wahl, P. & Jakob, R.P. (2010) Avoiding intraoperative complications in open-wedge high tibial valgus osteotomy: technical advancement. *Knee Surgery, Sports Traumatology, Arthroscopy*, 18(2), 200–203. Available from: https://doi.org/10.1007/s00167-009-0928-4

22. Jacquet, C., Marret, A., Myon, R., Ehlinger, M., Bahlouli, N., Wilson, A. et al. (2020) Adding a protective screw improves hinge's axial and torsional stability in high tibial osteotomy. *Clinical Biomechanics*, 74, 96–102. Available from: https://doi.org/10.1016/j.clinbiomech.2020.02.015

23. Jeong, J.H., Chang, M.C. & Lee, S.A. (2019) Deep peroneal nerve palsy after opening wedge high tibial osteotomy: a case report. *Medicine*, 98(27), e16253. Available from: https://doi.org/10.1097/MD.0000000000016253

24. Jung, W.-H., Chun, C.-W., Lee, J.-H., Ha, J.-H., Kim, J.-H. & Jeong, J.-H. (2013) Comparative study of medial opening-wedge high tibial osteotomy using 2 different implants. *Arthroscopy: The Journal of Arthroscopic & Related Surgery*, 29(6), 1063–1071. Available from: https://doi.org/10.1016/j.arthro.2013.02.020

25. Kim, J., Allaire, R. & Harner, C.D. (2010) Vascular safety during high tibial osteotomy: a cadaveric angiographic study. *The American Journal of Sports Medicine*, 38(4), 810–815. Available from: https://doi.org/10.1177/0363546510363664

26. Kim, J.I., Kim, B.H., Lee, K.W., Lee, O., Han, H.S., Lee, S. et al. (2016) Lower limb length discrepancy after high tibial osteotomy: prospective randomized controlled trial of lateral closing versus medial opening wedge osteotomy. *The American Journal of Sports Medicine*, 44(12), 3095–3102. Available from: https://doi.org/10.1177/0363546516659284

27. Lash, N.J., Feller, J.A., Batty, L.M., Wasiak, J. & Richmond, A.K. (2015) Bone grafts and bone substitutes for opening-wedge osteotomies of the knee: a systematic review. *Arthroscopy: The Journal of Arthroscopic & Related Surgery*, 31(4), 720–730. Available from: https://doi.org/10.1016/j.arthro.2014.09.011

28. Luites, J.W.H., Brinkman, J.-M., Wymenga, A.B. & van Heerwaarden, R.J. (2009) Fixation stability of opening-

versus closing-wedge high tibial osteotomy: a randomised clinical trial using radiostereometry. *The Journal of Bone and Joint Surgery. British Volume*, 91(11), 1459–1465. Available from: https://doi.org/10.1302/0301-620X.91B11.22614

29. Lustig, S., Scholes, C.J., Costa, A.J., Coolican, M.J. & Parker, D.A. (2013) Different changes in slope between the medial and lateral tibial plateau after open-wedge high tibial osteotomy. *Knee Surgery, Sports Traumatology, Arthroscopy*, 21(1), 32–38. Available from: https://doi.org/10.1007/s00167-012-2229-6

30. Mabrouk, A., Risebury, M. & Yasen, S. (2024) High survivorship and low complication rate in a single-centre series of 651 medial opening wedge high tibial osteotomy cases with a mean follow-up of 13 years. *Knee Surgery, Sports Traumatology, Arthroscopy*, 32(3), 736–749. Available from: https://doi.org/10.1002/ksa.12096

31. Martin, R., Birmingham, T.B., Willits, K., Litchfield, R., Lebel, M.-E. & Giffin, J.R. (2014) Adverse event rates and classifications in medial opening wedge high tibial osteotomy. *The American Journal of Sports Medicine*, 42(5), 1118–1126. Available from: https://doi.org/10.1177/0363546514525929

32. Moon, S.W., Park, S.H., Lee, B.H., Oh, M., Chang, M., Ahn, J.H. et al. (2015) The effect of hinge position on posterior tibial slope in medial open-wedge high tibial osteotomy. *Arthroscopy: The Journal of Arthroscopic & Related Surgery*, 31(6), 1128–1133. Available from: https://doi.org/10.1016/j.arthro.2015.01.009

33. Nakamura, R., Komatsu, N., Fujita, K., Kuroda, K., Takahashi, M., Omi, R. et al. (2017) Appropriate hinge position for prevention of unstable lateral hinge fracture in open wedge high tibial osteotomy. *The Bone & Joint Journal*, 99-B(10), 1313–1318. Available from: https://doi.org/10.1302/0301-620X.99B10.BJJ-2017-0103.R1

34. Nakamura, R., Komatsu, N., Murao, T., Okamoto, Y., Nakamura, S., Fujita, K. et al. (2015) The validity of the classification for lateral hinge fractures in open wedge high tibial osteotomy. *The Bone & Joint Journal*, 97-B(9), 1226–1231. Available from: https://doi.org/10.1302/0301-620X.97B9.34949

35. Nelissen, E.M., van Langelaan, E.J. & Nelissen, R.G.H.H. (2010) Stability of medial opening wedge high tibial osteotomy: a failure analysis. *International Orthopaedics*, 34(2), 217–223. Available from: https://doi.org/10.1007/s00264-009-0723-3

36. Nerhus, T.K., Ekeland, A., Solberg, G., Olsen, B.H., Madsen, J.E. & Heir, S. (2017) No difference in time-dependent improvement in functional outcome following closing wedge versus opening wedge high tibial osteotomy: a randomised controlled trial with two-year follow-up. *The Bone & Joint Journal*, 99-B(9), 1157–1166. Available from: https://doi.org/10.1302/0301-620X.99B9.BJJ-2017-0062.R1

37. Nerhus, T.K., Ekeland, A., Solberg, G., Sivertsen, E.A., Madsen, J.E. & Heir, S. (2017) Radiological outcomes in a randomized trial comparing opening wedge and closing wedge techniques of high tibial osteotomy. *Knee Surgery, Sports Traumatology, Arthroscopy*, 25(3), 910–917. Available from: https://doi.org/10.1007/s00167-015-3817-z

38. Niinimäki, T.T., Eskelinen, A., Ohtonen, P., Junnila, M. & Leppilahti, J. (2012) Incidence of osteotomies around the knee for the treatment of knee osteoarthritis: a 22-year population-based study. *International Orthopaedics*, 36(7), 1399–1402. Available from: https://doi.org/10.1007/s00264-012-1508-7

39. Ogawa, H., Matsumoto, K. & Akiyama, H. (2017) The prevention of a lateral hinge fracture as a complication of a medial opening wedge high tibial osteotomy: a case control study. *The Bone & Joint Journal*, 99-B(7), 887–893. Available from: https://doi.org/10.1302/0301-620X.99B7.BJJ-2016-0927.R1

40. Ollivier, B., Berger, P., Depuydt, C. & Vandenneucker, H. (2021) Good long-term survival and patient-reported outcomes after high
tibial osteotomy for medial compartment osteoarthritis. *Knee Surgery, Sports Traumatology, Arthroscopy*, 29(11), 3569-3584.
Available from: https://doi.org/10.1007/s00167-020-06262-4

41. Pape, D., Kohn, D., van Giffen, N., Hoffmann, A., Seil, R. & Lorbach, O. (2013) Differences in fixation stability between spacer plate and plate fixator following high tibial osteotomy. *Knee Surgery, Sports Traumatology, Arthroscopy*, 21(1), 82–89.
Available from: https://doi.org/10.1007/s00167-011-1693-8

42. Pape, D., Lorbach, O., Schmitz, C., Busch, L.C., Van Giffen, N., Seil, R. et al. (2010) Effect of a biplanar osteotomy on primary stability following high tibial osteotomy: a biomechanical cadaver study. *Knee Surgery, Sports Traumatology, Arthroscopy*, 18(2), 204–211. Available from: https://doi.org/10.1007/s00167-009-0929-3

43. Park, H., Kim, H.W., Kam, J.H. & Lee, D.H. (2017) Open wedge high tibial osteotomy with distal tubercle osteotomy lessens change in patellar position. *BioMed Research International*, 2017, 1–10.
Available from: https://doi.org/10.1155/2017/4636809

44. van Raaij, T.M., Brouwer, R.W., Vlieger, R., Reijman, M. & Verhaar, J.A.N. (2008) Opposite cortical fracture in high tibial osteotomy: lateral closing compared to the medial opening-wedge technique. *Acta Orthopaedica*, 79(4), 508–514. Available from: https://doi.org/10.1080/17453670710015508

45. Reyle, G., Lorbach, O., Diffo Kaze, A., Hoffmann, A. & Pape, D. (2017) Verhinderung einer fraktur der gegenkortikalis bei aufklappender osteotomie: anteroposteriore bohrung als lösungsansatz. *Der Orthopäde*, 46(7), 610–616. Available from: https://doi.org/10.1007/s00132-017-3418-2

46. Rosteius, T., Rausch, V., Lotzien, S., Seybold, D., Schildhauer, T.A. & Geßmann, J. (2021) Treatment of aseptic nonunion after medial opening-wedge high tibial osteotomy. *European Journal of Orthopaedic Surgery & Traumatology*, 31(4), 755–762. Available from: https://doi.org/10.1007/s00590-020-02825-w

47. Rubens, F., Wellington, J.L. & Bouchard, A.G. (1990) Popliteal artery injury after tibial osteotomy: report of two cases. *Canadian journal of surgery. Journal canadien de chirurgie*, 33(4), 294–297.

48. Saragaglia, D., Chedal-Bornu, B., Rouchy, R.C., Rubens-Duval, B., Mader, R. & Pailhé, R. (2016) Role of computer-assisted surgery in osteotomies around the knee. *Knee Surgery, Sports Traumatology, Arthroscopy*, 24(11), 3387–3395. Available from: https://doi.org/10.1007/s00167-016-4302-z

49. Sawant, M.R. & Ireland, J. (2001) Pseudo-aneurysm of the anterior tibial artery complicating high tibial osteotomy—a case report. *The Knee*, 8(3), 247–248. Available from: https://doi.org/10.1016/S0968-0160(01)00066-7

50. Schröter, S., Gonser, C.E., Konstantinidis, L., Helwig, P. & Albrecht, D. (2011) High complication rate after biplanar open wedge high tibial osteotomy stabilized with a new spacer plate (position HTO plate) without bone substitute. *Arthroscopy: The Journal of Arthroscopic & Related Surgery*, 27(5), 644–652. Available from: https://doi.org/10.1016/j.arthro.2011.01.008

51. Shen, G., Shen, D., Fang, Y., Li, X., Cui, L., Wei, B. et al. (2022) Clinical outcomes of revision total knee arthroplasty after high tibial osteotomy and unicompartmental knee arthroplasty: a systematic review and meta-analysis. *Orthopaedic Surgery*, 14(8), 1549–1557.
Available from: https://doi.org/10.1111/os.13311

52. Shenoy, P.M., Oh, H.K., Choi, J.Y., Yoo, S.H., Han, S.B., Yoon, J.R. et al. (2009) Pseudoaneurysm of the popliteal artery complicating medial opening wedge high tibial osteotomy. *Orthopedics*, 32(6), 442. Available from: https://doi.org/10.3928/01477447-20090511-29

53. Shin, Y.-S., Sim, H.-B. & Yoon, J.-R. (2017) Tibial nerve neuropathy following medial opening-wedge high tibial osteotomy-case report

of a rare technical complication. *European Journal of Orthopaedic Surgery & Traumatology*, 27(4), 563–567. Available from: https://doi.org/10.1007/s00590-017-1944-6

54. Slevin, O., Ayeni, O.R., Hinterwimmer, S., Tischer, T., Feucht, M.J. & Hirschmann, M.T. (2016) The role of bone void fillers in medial opening wedge high tibial osteotomy: a systematic review. *Knee Surgery, Sports Traumatology, Arthroscopy*, 24(11), 3584–3598. Available from: https://doi.org/10.1007/s00167-016-4297-5

55. Suh, D.W., Nha, K.W., Han, S.B., Cheong, K. & Kyung, B.S. (2022) Biplane medial opening-wedge high tibial osteotomy increases posterior tibial slope more than uniplane osteotomy. *The Journal of Knee Surgery*, 35(11), 1229–1235. Available from: https://doi.org/10.1055/s-0040-1722659

56. Szyber Jr., P., Skóra, P., Rybak, P. & Pupka, P. (2011) Iatrogenic pseudoaneurysm of the popliteal artery following corrective tibial osteotomy. *Vasa. Zeitschrift fuer Gefaesskrankheiten*, 40(5), 414–417. Available from: https://doi.org/10.1024/0301-1526/a000140

57. Takeuchi, R., Ishikawa, H., Kumagai, K., Yamaguchi, Y., Chiba, N., Akamatsu, Y. et al. (2012) Fractures around the lateral cortical hinge after a medial opening-wedge high tibial osteotomy: a new classification of lateral hinge fracture. *Arthroscopy: The Journal of Arthroscopic & Related Surgery*, 28(1), 85–94. Available from: https://doi.org/10.1016/j.arthro.2011.06.034

58. Tandon, S.C., Kharbanda, Y. & Fraser, A.M. (1996) Aneurysm complicating high tibial osteotomy: a case report. *Acta Orthopaedica Scandinavica*, 67(1), 73–74. Available from: https://doi.org/10.3109/17453679608995615

59. Wang, J.H., Bae, J.H., Lim, H.C., Shon, W.Y., Kim, C.W. & Cho, J.W. (2009) Medial open wedge high tibial osteotomy: the effect of the cortical hinge on posterior tibial slope. *The American Journal of Sports Medicine*, 37(12), 2411–2418. Available from: https://doi.org/10.1177/0363546509341174

60. W-Dahl, A., Robertsson, O. & Lohmander, L.S. (2012) High tibial osteotomy in Sweden, 1998-2007: a population-based study of the use and rate of revision to knee arthroplasty. *Acta Orthopaedica*, 83(3), 244–248. Available from: https://doi.org/10.3109/17453674.2012.688725

61. Woodacre, T., Ricketts, M., Evans, J.T., Pavlou, G., Schranz, P., Hockings, M. et al. (2016) Complications associated with opening wedge high tibial osteotomy—a review of the literature and of 15 years of experience. *The Knee*, 23(2), 276–282.
Available from: https://doi.org/10.1016/j.knee.2015.09.018

62. Yang, J.-H., Lee, S.-H., Nathawat, K.S., Jeon, S.-H. & Oh, K.-J. (2013) The effect of biplane medial opening wedge high tibial osteotomy on patellofemoral joint indices. *The Knee*, 20(2), 128–132. Available from: https://doi.org/10.1016/j.knee.2012.09.019