Joint-preserving surgery in varus ankle osteoarthritis

  Citation: Alajlan, A.; Santini, S.; Alsayel, F.; Teoh, K.H.; Alharbi, W.; Puls, L.; Camathias, C.; Herrera-Pérez, M.; Tejero, S.; Barg, A.; et al. Joint-Preserving Surgery in Varus Ankle Osteoarthritis. J. Clin. Med. 2022,11, 2194. https:// doi.org/10.3390/jcm11082194 Academic Editor: Gerald Atkins Received: 25 February 2022 Accepted: 12 April 2022 Published: 14 April 2022 Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations. Copyright: © 2022 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/). Journal of Clinical Medicine Review Joint-Preserving Surgery in Varus Ankle Osteoarthritis Ahmad Alajlan 1,†, Simone Santini 2,† , Faisal Alsayel 3, Kar H. Teoh 4, Waheeb Alharbi 5, Luise Puls 6, Carlo Camathias 7, Mario Herrera-Pérez 8, Sergio Tejero 9, Alexej Barg 10, Martin Wiewiorski 11 and Victor Valderrabano 6,* 1Department of Orthopedic Surgery, Security Forces Hospital, P.O. Box 3643, Riyadh 11481, Saudi Arabia; [email protected] 2Department of Orthopaedics and Trauma Surgery, University Campus Bio-Medico of Rome, 00128 Rome, Italy; [email protected] 3Department of Orthopedic Surgery, King Fahad Specialist Hospital, P.O. Box 15215, Dammam 31444, Saudi Arabia; [email protected] 4Princess Alexandra Hospital NHS Trust, Harlow CM20 1QX, UK; kar[email protected] 5King Fahad Armed Forces Hospital, Al Kurnaysh Rd, Al Andalus, Jeddah 23311, Saudi Arabia; dr[email protected] 6 Swiss Ortho Center, Swiss Medical Network, Schmerzklinik Basel, Hirschgasslein 15, 4010 Basel, Switzerland; [email protected] 7Medical Faculty, University of Basel, 4056 Basel, Switzerland; [email protected] 8Head Foot and Ankle Unit, Orthopaedic Department, University of La Laguna, 38200 San Cristóbal de La Laguna, Spain; [email protected] 9 Foot and Ankle Unit, Orthopedic Surgery and Traumatology Service, Hospital Universitario Virgen del Rocío, Av. Manuel Siurot, s/n, 41013 Sevilla, Spain; tejerogar[email protected] 10 Department of Orthopaedics, University of Utah, 590 Wakara Way, Salt Lake City, UT 84108, USA; [email protected] 11 WinOrtho, Privatklinik Lindberg, Schickstrasse 11, 8400 Winterthur, Switzerland; [email protected] *Correspondence: [email protected] † These authors contributed equally to this work. Abstract: Ankle deformity is a disabling condition especially if concomitant with osteoarthritis (OA). Varus ankle OA is one of the most common ankle OA deformities. This deformity usually leads to unequal load distribution in the ankle joint and decreases joint contact surface area, leading to a progressive degenerative arthritic situation. Varus ankle OA might have multiple causative factors, which might present as a single isolated factor or encompassed together in a single patient. The etiologies can be classified as post-traumatic (e.g., after fractures and lateral ligament instability), degenerative, systemic, neuromuscular, congenital, and others. Treatment options are determined by the degree of the deformity and analyzing the pathology, which range from the conservative treatments up to surgical interventions. Surgical treatment of the varus ankle OA can be classified into two categories, joint-preserving surgery (JPS) and joint-sacrificing surgery (JSS) as total ankle arthroplasty and ankle arthrodesis. JPS is a valuable treatment option in varus ankle OA, which should not be neglected since it has showed a promising result, optimizing biomechanics and improving the survivorship of the ankle joint. Keywords: supramalleolar osteotomy; ankle osteoarthritis; varus ankle; joint preserving surgery 1. Introduction Varus ankle osteoarthritis (OA) is caused by a deviation of the ankle’s mechanical and anatomical axes toward the medial. Asymmetric cartilage attrition and joint abnormalities are caused by uneven tension on the joint surface, which eventually leads to OA [1]. The medial talar dome and tibia plafond, as well as the medial gutter of the tibiotalar joint, are commonly affected. Varus ankle OA is characterized by talus malpositioning, which includes medial talus translation, internal rotation along the longitudinal talus axis, J. Clin. Med. 2022,11, 2194. https://doi.org/10.3390/jcm11082194 https://www.mdpi.com/journal/jcm J. Clin. Med. 2022,11, 2194 2 of 14 and/or varus talar tilt [ 2 ]. The misalignment of the talus causes an eccentric load on the ankle when it is weight-bearing, which can exacerbate varus cartilage degradation [3]. The most common etiology of ankle OA is post-traumatic [4]. Several surgical techniques for various stages of ankle OA have been documented. Joint-preserving surgery (JPS) and joint-sacrificing surgery (JSS) are the two types of procedures. Osteochondral resurfacing treatments, distraction arthroplasty, ankle arthroscopic debridement, and periankle corrective osteotomies are all joint-preserving operations [5]. Graehl et al. [ 5 ] in 1987 performed a supramalleolar osteotomy on eight patients symptomatic from a malunion of the distal two thirds of the tibia leading to varus ankle. Takakura et al. [ 6 ] performed in 1995 a low tibial osteotomy on 18 patients affected by post-traumatic ankle varus osteoarthritis, and Hintermann et al. [ 7 ] also used this type of osteotomy for malunited pronation-external rotation fractures of the ankle, both with good outcomes. Joint-sacrificing surgeries (JSS) consist in total ankle arthroplasty (TAA) and ankle arthrodesis. They both have their own advantages and an important role in varus ankle OA treatment, but they also might have long-term issues [ 5 ]. Since patients with post-traumatic ankle OA become symptomatic around 12 to 15 years earlier than patients with knee or hip OA [ 8 ], joint preserving, and long-lasting pain-relieving surgery is mandatory. The aim of this paper is to provide a review of the varus ankle OA issues and their treatments, conservatively and surgically. A description of JPS surgical technique, preoperative planning, and postoperative protocol is also provided. 2. Etiology and Biomechanics of the Varus Ankle and Hindfoot 2.1. Etiology Ankle joint is rarely affected by primary OA. The most prevalent etiology of ankle OA is post-traumatic, with varus being the most common malalignment, according to previous clinical and epidemiologic investigation, most commonly following ankle fractures and lower leg fractures [ 1 , 3 ] and/or repetitive lateral ankle sprains/lateral chronic ankle instability [ 9 ]. (Table 1). Bone abnormalities, chronic ligament insufficiency, muscular imbalance, or a combination of these factors can all contribute to a varus deformity. Neurologic illnesses can have a significant impact on the development of varus deformity. These pathologic disorders start out as correctable malformations, but they can become stiff with time, causing aberrant biomechanics in the foot and ankle, as well as subsequent complications, resulting in secondary OA with fixed varus or cavovarus deformity. Table 1. Etiologies of the Varus Ankle Osteoarthritis (OA). Post-Traumatic Varus malunion of tibial shaft fractures Varus malunion of tibial plafond fractures or malleolar fractures Varus malunion of talus and calcaneus fractures Avascular necrosis of talus Chronic lateral ankle ligament instability Postcompartment syndrome Degenerative Rheumatoid osteoarthritis Varus knee osteoarthritis Charcot osteoarthropathy Neuromuscular Stroke Central and peripheral nerve disorders Hereditary motor sensory neuropathy/Charcot–Marie–Tooth disease Polio Cerebral palsy Peroneal brevis muscle insufficiency Peroneal tendon ruptures J. Clin. Med. 2022,11, 2194 3 of 14 Table 1. Cont. Congenital Residual clubfoot (Talipes equinovarus) Tarsal coalition Excessive tibial external rotation 2.2. Biomechanics A deformity in the lower leg, ankle, hindfoot, midfoot, or forefoot causes ankle varus and cavovarus deformities. When the problem occurs in the hindfoot, as it is in patients with lateral chronic ankle instability and peroneal brevis muscle weakening, the talus makes a pathologic internal rotation and anterior subluxation, resulting in an asymmetric medial ankle OA over time [ 10 ]. When this happens, the forefoot goes into supination and the hindfoot goes into varus. With such an internally rotated foot deformity, the patient is unable to walk. As a result, the forefoot attempts to compensate by flexing the Metatarsus primus due to an overactive Peroneus longus muscle. The patient walks with a varus hindfoot and a plantigrade forefoot in this position, creating over time also a varus ankle OA model [10]. In essence, as Apostle et al. mention in their article, most of the deformity in a varus ankle might arise from the foot’s attempt at compensation. Over time, these compensatory mechanisms in turn become additional deforming factors [10]. However, the patient is typically in a vicious circle: shifting of the mechanical axis leads to unequal load distribution and decreases the surface contact forces and compartment overload [ 10 ]. Regardless of the primary etiology, the supporters of the ankle joint, soft tissue (lateral ligament insufficiency and deltoid ligament contracture), and bony tissue (tibia, talus, and calcaneus) both are eventually elicited and subject to degenerative changes. Therefore, proper management to cut the cascade is needed to stop the progression [10]. 3. Clinical Assessment A varus alignment is not always limited to the ankle. It is important to expose all of the lower limb in order to estimate the axis and any other deformity. The patient is inspected barefoot, both when walking and standing [ 11 ]. The alignment, deformities, and foot/ankle/hindfoot position are visually assessed [ 2 ]. An examination of the foot in standing position may reveal heel varus, cavus, and/or first-ray plantarflexion (forefootdriven hindfoot varus). To measure the influence of the first ray on the varus hindfoot position and flexibility, the Coleman Block test can be used [ 10 ]. Tender regions along the path of the ankle joint medial, ventral, lateral, and posterior are given extra attention during palpation, as well as lateral and medial ligament complexes [ 2 ]. In addition, all the tendons around the ankle/hindfoot should be checked for tenderness. Then, range of motion (ROM) of the tibiotalar joint (plantarflexion/dorsiflexion) and subtalar joint (eversion/inversion) is measured, as well as of the Chopart joint [ 12 ]. Following the ROM, the ligament stability of the lateral ankle ligaments and Deltoid medial is documented [ 2 ]. Muscle atrophy and functional status should be checked. Muscle force evaluation should be checked by M0-5, in all main movement planes: plantarflexion, dorsiflexion, inversion, and eversion [ 12 ]. Further, particular attention should be paid to any potential tightness, such as to the Gastocnemius–Soleus complex or the posterior tibial muscle [ 12 ]. Finally, the patient’s neurovascular state should be assessed, with particular attention paid to the integrity of the peroneal and tibial nerves. 3.1. Imaging Modalities Standing X-rays are required as part of the radiographic evaluation: dorsoplantar and lateral plain radiographs of the foot, ankle AP mortise, and hindfoot alignment view (Saltzman view). Furthermore, whole-leg radiographs are required to evaluate osseous abnormalities across the lower extremity, as hip and knee influence the overall alignment. J. Clin. Med. 2022,11, 2194 4 of 14 Magnetic resonance imaging (MRI) is helpful to assess the cartilage of the ankle joint, ligaments, tendon, and muscular pathologies [ 13 ]. Preoperative CT scans, such as SPECTCT [ 11 ] or a weight-bearing CT (WBCT), can aid to better comprehend the case, evaluate the bone quality, and locate cysts. According to the Takakura staging system, there are four grades of a varus ankle osteoarthritis on weight-bearing anteroposterior (AP) radiographs: (1) Physiologic jointspace, osteophytes and early sclerosis; (2) Narrowing of the join space, only on the medial side; (3A) Subchondral bone contact with obliteration of the medial malleolus’ joint space; (3B) Subchondral bone contact with joint space obliteration extending to the talar dome’s roof; (4) Obliteration of the entire joint surface, bone on bone contact [14]. A categorical contraindication to performing a supramalleolar osteotomy is end-stage ankle osteoarthritis involving more than half of the tibiotalar joint surface [ 15 ], so a preop MRI study is necessary to assess the precise localization and extension of the chondral damage [12]. 3.2. Preoperative Radiological Angle Measurements On the anteroposterior view, the medial distal–tibial angle (MDTA: normal range 93.3 ± 3.2 degrees, also known as tibial anterior surface angle (TAS) formed by the mechanical axis of the tibia and the tangent of the tibial plafond on the medial side of the ankle (Figure 1). The MDTA in varus ankle OA is <90 ◦ and is overcorrected postoperatively over the physiological average by 2–5◦. J. Clin. Med. 2022, 11, x FOR PEER REVIEW 4 of 14 abnormalities across the lower extremity, as hip and knee influence the overall alignment. Magnetic resonance imaging (MRI) is helpful to assess the cartilage of the ankle joint, ligaments, tendon, and muscular pathologies [13]. Preoperative CT scans, such as SPECTCT [11] or a weight-bearing CT (WBCT), can aid to better comprehend the case, evaluate the bone quality, and locate cysts. According to the Takakura staging system, there are four grades of a varus ankle osteoarthritis on weight-bearing anteroposterior (AP) radiographs: (1) Physiologic jointspace, osteophytes and early sclerosis; (2) Narrowing of the join space, only on the medial side; (3A) Subchondral bone contact with obliteration of the medial malleolus’ joint space; (3B) Subchondral bone contact with joint space obliteration extending to the talar dome’s roof; (4) Obliteration of the entire joint surface, bone on bone contact [14]. A categorical contraindication to performing a supramalleolar osteotomy is endstage ankle osteoarthritis involving more than half of the tibiotalar joint surface [15], so a preop MRI study is necessary to assess the precise localization and extension of the chondral damage [12]. 3.2. Preoperative Radiological Angle Measurements On the anteroposterior view, the medial distal–tibial angle (MDTA: normal range 93.3 ± 3.2 degrees, also known as tibial anterior surface angle (TAS) formed by the mechanical axis of the tibia and the tangent of the tibial plafond on the medial side of the ankle (Figure 1). The MDTA in varus ankle OA is <90° and is overcorrected postoperatively over the physiological average by 2–5°. Figure 1. Cont. J. Clin. Med. 2022,11, 2194 5 of 14 J. Clin. Med. 2022, 11, x FOR PEER REVIEW 5 of 14 Figure 1. Angles for the Radiological Evaluation of a Varus Ankle Osteoarthritis. On the anteroposterior view, tibial anterior surface angle TAS (also known as medial distal tibial angle MDTA) tibiotalar surface (TTS) and talar tilt (TT) angle are shown (A). On lateral ankle radiograph, the tibial lateral surface angle (TLS) is assessed (B). The talar-1st metatarsal angle gives us a hint about the amount of midfoot deformity, both on lateral and dorsoplantar view (B,C). Inframalleolar deformity can be evaluated on the Saltzman view by measuring the hindfoot alignment view (HAV) angle (D). Further, in the ap view, the tibiotalar surface angle (TTS; normal range; 87.2 ± 2.8 degrees) is measured [13,14]. The TTS in varus ankle OA is <84.4°. The talar tilt (TT) angle is used to assess tibiotalar congruence. The tibial articular surface and the talar articular surface on the AP X-ray produce this angle. It is usually less than 4 degrees [15]. In the AP view, these criteria can be used to assess syndesmotic integrity: The tibiofibular clear space (TFCS) has a normal range of 6 mm, and the tibiofibular overlap (TFO) has a normal range of >1 mm in mortise view and >6 mm in AP view [16]. In the mortise view, disruption of Shenton’s line and the dime sign/Weber circle at the tip of the fibula/lateral talar process, frequently seen in anomalous fibular length [17,18]. On a lateral ankle radiograph, the tibial lateral surface (TLS) angle is measured using the mechanical axis of the tibia and a line passing across the ends of the tibial articular surface in a lateral view, with a typical range of 83.0 ± 3.6 degrees [19]. Inframalleolar deformity can be evaluated on the (Saltzman view) by measuring the hindfoot alignment view (HAV) angle between the anatomical axis of the tibia and the axis of the calcaneus. Normally, HAV has a value of 0–5° [20]. The Saltzman view can also be useful for detecting subtalar malalignment [21]. The lateral talar-1st metatarsal angle is an index of midfoot deformity magnitude. Pes planus is defined as a downward convex angle larger than 4° [22]. 3.3. Conservative Treatment of Varus Ankle Osteoarthritis There are many conservative treatments available for treating ankle OA. They all are symptomatic, with the main purpose of pain alleviation. Since the amount of specific literature for ankle OA is low, the choice is usually based on physician experience or patient tendencies. It is advised that the conservative treatment be for at least 3–6 months, before evaluating a surgical treatment [23]. Oral nonsteroidal anti-inflammatory drugs (NSAIDs) certainly have a big role in addressing pain and inflammation both. Although there are few scientific publications on Figure 1. Angles for the Radiological Evaluation of a Varus Ankle Osteoarthritis. On the anteroposterior view, tibial anterior surface angle TAS (also known as medial distal tibial angle MDTA) tibiotalar surface (TTS) and talar tilt (TT) angle are shown ( A ). On lateral ankle radiograph, the tibial lateral surface angle (TLS) is assessed ( B ). The talar-1st metatarsal angle gives us a hint about the amount of midfoot deformity, both on lateral and dorsoplantar view ( B , C ). Inframalleolar deformity can be evaluated on the Saltzman view by measuring the hindfoot alignment view (HAV) angle (D). Further, in the ap view, the tibiotalar surface angle (TTS; normal range; 87.2 ± 2.8 degrees) is measured [13,14]. The TTS in varus ankle OA is <84.4◦. The talar tilt (TT) angle is used to assess tibiotalar congruence. The tibial articular surface and the talar articular surface on the AP X-ray produce this angle. It is usually less than 4 degrees [15]. In the AP view, these criteria can be used to assess syndesmotic integrity: The tibiofibular clear space (TFCS) has a normal range of 6 mm, and the tibiofibular overlap (TFO) has a normal range of >1 mm in mortise view and >6 mm in AP view [16]. In the mortise view, disruption of Shenton’s line and the dime sign/Weber circle at the tip of the fibula/lateral talar process, frequently seen in anomalous fibular length [17,18]. On a lateral ankle radiograph, the tibial lateral surface (TLS) angle is measured using the mechanical axis of the tibia and a line passing across the ends of the tibial articular surface in a lateral view, with a typical range of 83.0 ±3.6 degrees [19]. Inframalleolar deformity can be evaluated on the (Saltzman view) by measuring the hindfoot alignment view (HAV) angle between the anatomical axis of the tibia and the axis of the calcaneus. Normally, HAV has a value of 0–5 ◦ [ 20 ]. The Saltzman view can also be useful for detecting subtalar malalignment [21]. The lateral talar-1st metatarsal angle is an index of midfoot deformity magnitude. Pes planus is defined as a downward convex angle larger than 4◦[22]. 3.3. Conservative Treatment of Varus Ankle Osteoarthritis There are many conservative treatments available for treating ankle OA. They all are symptomatic, with the main purpose of pain alleviation. Since the amount of specific literature for ankle OA is low, the choice is usually based on physician experience or patient tendencies. It is advised that the conservative treatment be for at least 3–6 months, before evaluating a surgical treatment [23]. Oral nonsteroidal anti-inflammatory drugs (NSAIDs) certainly have a big role in addressing pain and inflammation both. Although there are few scientific publications on J. Clin. Med. 2022,11, 2194 6 of 14 the usefulness of NSAIDS in the treatment of ankle OA, their value has been demonstrated in a number of level I arthritic trials [23]. The use of viscosupplementation oral (glucosamine or chondroitin sulfate) or by injection (hyaluronic acid) has a place in the treatment of ankle OA. The clinical benefit of oral viscosupplementation with glucosamine or chondroitin sulfate in knee OA has been demonstrated in several studies [ 24 ] However, the effect of this treatment in patients with ankle OA remains underexplored. Nevertheless, first results show that oral viscosupplementation could also be effective in ankle OA [25]. A substantial improvement in OA ankles was reported in a prospective randomized double-blind trial following 1 and 6 months of 5 weekly hyaluronic acid injections [ 26 ]. In addition, three weekly injections have been found capable to improve the Ankle Osteoarthritis Scale and American Orthopedic Foot and Ankle Society Hindfoot Score [27]. In orthopedic surgery, platelet-rich plasma (PRP) has gained popularity since it is thought to biologically stimulate musculoskeletal tissues repair, but for now its use in foot and ankle applications is supported only by limited clinical evidence [28]. The use of corticosteroid injection can decrease inflammation and pain [ 29 ], but due to its catabolic nature and the risk of damaging soft tissues, it is not for long-term use [23]. Physical therapies are frequently suggested to help increase strength and ROM. Training of peroneal muscles, proprioception exercises, Achilles tendon stretching, ankle mobilization, and gait education are examples of the main core of a physical therapy program. Muscle strength in dorsiflexion and plantarflexion has been reported to be reduced in those with ankle arthritis [30]. Since in varus ankle OA the cartilage is more compromised on the medial side, the use of insoles with lateral wedge can shift the load axis to the unaffected side, therefore unloading the osteoarthritic side of the joint [23]. 3.4. Surgical Treatment of the Varus Ankle Osteoarthritis Once nonoperative measures have been used without improvement, surgical intervention is indicated. Especially in patients whose symptoms increase in terms of pain, instability, or progress in radiological arthritic changes. The surgical options are jointpreserving surgery (JPS) or joint-sacrificing surgery (JSS), i.e., total ankle arthroplasty or ankle arthrodesis [ 5 ]. A painless/pain-free, plantigrade, completely functional, and stable ankle and foot is the goal of any reconstructive surgery. Recognizing the associated deformities, such as lateral chronic ankle instability, varus heel, hindfoot OA, overfiring of muscles (posterior tibial muscle and peroneus longus), insufficiency of muscles (peroneus brevis), forefoot malalignment, lesser toes deformities, Achilles tendon tightness, knee deformities, and contralateral lower limb malalignment is required for effective treatment of the varus ankle [5]. 3.5. Joint-Preserving Surgery (JPS) Choosing the type of surgical intervention and optimizing it depends on analyzing the pathology (etiological factors), in addition to addressing the associated comorbidity and the proper time for the surgical intervention. Table 2summarizes the main indications and contraindications for a JPS. The key indication is varus ankle OA with a lateral partially maintained tibiotalar joint (at least 50%). A supramalleolar osteotomy (SMOT) can also be used to correct the hindfoot realignment before a total ankle arthroplasty. Patients aged >70 and hindfoot instability are a relative contraindication, while absolute contraindications are end-stage OA and hindfoot instability unmanageable with ligament reconstruction [ 8 ]. J. Clin. Med. 2022,11, 2194 7 of 14 Table 2. Indications, Contraindications, Special risks, and Pitfalls for Joint-Preserving Surgery of Asymmetric Varus Ankle Osteoarthritis (OA). Indications Asymmetric medial ankle OA with associated varus deformity and a lateral partially preserved tibiotalar joint Osteochondral lesions on the medial talar side of the tibiotalar joint Post-traumatic varus deformities after lower leg fractures Ankle–hindfoot realignment before or together with total ankle arthroplasty Contraindications End-stage OA of the ankle with more than half of the tibiotalar joint surface involved Unmanageable ankle–hindfoot instability/neuromuscular imbalance Osteomyelitis or infection Severe vascular and/or neurologic deficiency Relative Contraindications Tobacco use (because of most likely expected high rate of nonunion or delayed union) Advanced age (>70 years) Patients in poor general health who are unable to accomplish nonweight-bearing rehabilitation after surgery Untreated diabetes mellitus (with or without diabetic polyneuropathy) Altered bone quality due to medication (e.g., long-term medication with steroids) Large cysts Osteopenia or osteoporosis Untreated rheumatoid osteoarthritis Special Risks and Pitfalls Intraoperative injury of neurovascular structures and/or tendons Wound healing problems/infections Under correction/overcorrection Loss of correction due to OA progression Delayed union/nonunion Hardware removal because of pain/discomfort Corrective surgery is difficult and may not be achievable as a stand-alone operation; moreover a 3D reconstruction to the foot and ankle might be needed in the severe deformity situation. The SMOT (medial open tibia or lateral closing wedge tibia/fibula) has the main role in varus ankle OA correction, along with a calcaneus osteotomy (e.g., Sliding and Dwyer) to address a residual varus hindfoot; a reversed Cotton OT/Dorsiflexion Metatarsal-I-OT to correct the medial foot column; deltoid release or lateral ankle ligament reconstruction to manage deltoid contracture or lateral ankle instability; PL-to-PB-tendon transfer to enhance foot eversion; and posterior tibial tendon elongation or transfer to manage the inversion contracture [8]. 3.6. Supramalleolar Osteotomy The aims of supramalleolar osteotomy (SMOT) are to shift the lower-leg/ankle axis to lateral, where there is still good cartilage and to improve intraarticular load distribution by shifting and equalizing the forces and the stresses in the joint and delay the arthritic changes in the tibiotalar joint [ 15 , 31 ]. Multiple factors need to be considered prior to choose your osteotomy. The osteotomy can be performed in one of two ways: medial tibial opening wedge or lateral tibial–fibular closing wedge. The type of SMOT is determined by the deformity’s angle: If the angle is greater than 10 degrees, a lateral closed wedge osteotomy is conceivable; if the angle is less than 10 degrees, a medial open wedge osteotomy is possible [ 11 ]. It is wise to mention that, even if a leg length discrepancy up to 10 mm is tolerable according to several studies [ 32 ]. Lateral closing wedge SMOT has a greater joint deloading effect and might be more indicated in patients with skin or vascular problems. J. Clin. Med. 2022,11, 2194 8 of 14 4. Surgical Technique 4.1. Medial Open Wedge Supramalleolar Tibia Osteotomy General, epidural/spinal, and regional anesthetic are all options for surgery. The patient is positioned supine. To hold the leg in neutral rotation, a slight bump under the ipsilateral hip is frequently required. Then, on the upper leg, a pneumatic tourniquet is applied. Evaluate the imaging before draping to adjust the patient’s position, and apply the stress view to evaluate the ligament integrity. In addition to the preoperative MRI, anterior diagnostic ankle arthroscopy might be performed using standard portals to determine the degree of medial and lateral ankle cartilage loss [ 5 ]. The medial approach skin incision is made over the posterior distal tibia, avoiding the saphenous vein and nerve. It is critical to expose the tibia with minimal periosteum peeling in order to complete the osteotomy [ 32 ]. With the help of fluoroscopy, a K-wire from medial to the lateral tibial cortex is used to mark the plane of the osteotomy. Two other K-wires orientated anteroposteriorly on the tibia might be of help to control the rotation. Then, the osteotomy is made under Hohmann retractor protection by use of a broad oscillating saw, preserving, if possible, the lateral tibial cortex to act as a fulcrum for the opening wedge and to improve stability [ 32 ]. Irrigation is important in order to reduce the heat produced by the saw that may induce damage and slow the postoperative bone healing [ 32 ]. Then, the open wedge correction is performed in accordance with the preoperative planning: The mm open wedge distance depicts the amount of angular correction degrees, which were calculated on the standing X-rays preoperatively. The goal is to achieve 2–5 ◦ of overcorrection of the MDTA (normal range 93.3 ± 3.2 degrees, value in varus ankle OA < 90 ◦ ). Preserving the hinge in the lateral cortex is an added value to the osteotomy for the stability and to augment the healing [ 33 ]. If there is concern about breaking the lateral cortex while using the lamina spreader to reach the desire correction, a plate on the anterior or lateral tibial cortex gives good control of rotation/translation [ 32 ]. Biplanar correction, i.e., adding sagittal correction, is carried out to enhance talar coverage in case of anterior extrusion [ 33 ]. A bone autograft or allograft is used to fill the gap, and rigid plate fixation with angular stable screws is used to stabilize the correction. After completion of the tibial osteotomy, the ankle mortise is checked under fluoroscopy to evaluate joint congruency [ 13 ]. Joint incongruence can be the result of medial soft tissue contracture, bone formation in the lateral compartment of the ankle, or a too long or malposition fibula. In this case, soft tissue release, cheilectomy, and fibular osteotomy should be carried out until the appropriate position of the talus is obtained. After that, the heel position is evaluated clinically with the goal of achieving 1 ◦ to 5 ◦ valgus. Deformity that persists should be treated with a calcaneal osteotomy or subtalar arthrodesis [ 34 ]. The lateral ankle ligaments and peroneal tendon pathology should also be surgically addressed simultaneously [34]. Additional surgeries are described in Table 3. Table 3. Summary of Associated Deformities and Further Procedures Required in Addition to Supramalleolar Osteotomy (SMOT). Associated Deformities Further Procedure Required in Addition to Smot Osteochondral Lesion of the Medial Ankle (Talus, Tibia, and Plafond) Autologous Matrix-Induced Chondrogenesis (AMIC) Ventromedial Bony Ankle Impingement (Osteophytes) Ventromedial Cheilectomy Ankle Ligaments: Lateral Chronic Ankle Instability Deltoid Contracture Anatomical Lateral Ankle Ligament Reconstruction Deltoid Release (at medial malleolus) Varus Hindfoot with No Subtalar OA Lateral Sliding Calcaneal Osteotomy/Dwyer Calcaneal Osteotomy J. Clin. Med. 2022,11, 2194 9 of 14 Table 3. Cont. Associated Deformities Further Procedure Required in Addition to Smot Varus Hindfoot with Subtalar Osteoarthritis Valgisating Subtalar Arthrodesis Varus Hindfoot with Hindfoot Osteoarthritis (Subtalar and Talonavicular/Calcaneocuboidal) Valgisating Triple Arthrodesis Medial Malleolus Deformity (Erosion, Malposition . . . ) Medial Malleolus Osteotomy Tight Gastrocnemius–Soleus Complex Strayer or Proximal Gastrocnemius Recession Peroneal Tendon Pathologies Posterior Tibial Tendon Tightness Primary Repair or PL-to-PB-tendon transfer Posterior Tibial Tendon Elongation Pes Cavus Reversed Cotton Osteotomy ±Plantar Fascia Release Plantar Flexed First Metatarsal Dorsal Closing Wedge First Metatarsal Osteotomy Plantar Flexed First Metatarsal with Overdrive of Peroneal Longus Tendon Dorsal Closing Wedge First Metatarsal Osteotomy and PL-to-PB Tendon Transfer 4.2. Lateral Closing Wedge Supramalleolar Tibia and Fibula Osteotomy For lateral closing wedge osteotomy of the fibula and tibia, a lateral approach over the fibula is used [ 5 ]. The skin incision starts at the tip of the fibula to proximal over the distal third of the fibula. The fibula, the tibia, and the anterior syndesmosis are then exposed. To preserve ankle joint congruency with a lateral closing wedge osteotomy, shortening of the fibula is needed [ 5 ]. The fibula osteotomy is performed by a Z-shaped osteotomy at which the amount of fibula shortening is performed on both ends of the Z. The lateral part of the tibia is then prepared and protected by two Hohmann hooks, dorsal and anterior. Two K- wires are then placed in the tibia above the syndemosis in a converging way in accordance with the amount of correction that was preoperatively planned (MDTA angle) [ 27 ]. After that, the osteotomy is performed, and the gap is closed; the correction is stabilized with an angular stable plate. Finally, the position and length of the fibula is adjusted and secured with interfragmentary screws and a fibula plate [27]. See case example in Figure 2. J. Clin. Med. 2022, 11, x FOR PEER REVIEW 9 of 14 Varus Hindfoot with Hindfoot Osteoarthritis (Subtalar and Talonavicular/Calcaneocuboidal) Valgisating Triple Arthrodesis Medial Malleolus Deformity (Erosion, Malposition…) Medial Malleolus Osteotomy Tight Gastrocnemius–Soleus Complex Strayer or Proximal Gastrocnemius Recession Peroneal Tendon Pathologies Posterior Tibial Tendon Tightness Primary Repair or PL-to-PB-tendon transfer Posterior Tibial Tendon Elongation Pes Cavus Reversed Cotton Osteotomy ± Plantar Fascia Release Plantar Flexed First Metatarsal Dorsal Closing Wedge First Metatarsal Osteotomy Plantar Flexed First Metatarsal with Overdrive of Peroneal Longus Tendon Dorsal Closing Wedge First Metatarsal Osteotomy and PL-to- PB Tendon Transfer 4.2. Lateral Closing Wedge Supramalleolar Tibia and Fibula Osteotomy For lateral closing wedge osteotomy of the fibula and tibia, a lateral approach over the fibula is used [5]. The skin incision starts at the tip of the fibula to proximal over the distal third of the fibula. The fibula, the tibia, and the anterior syndesmosis are then exposed. To preserve ankle joint congruency with a lateral closing wedge osteotomy, shortening of the fibula is needed [5]. The fibula osteotomy is performed by a Z-shaped osteotomy at which the amount of fibula shortening is performed on both ends of the Z. The lateral part of the tibia is then prepared and protected by two Hohmann hooks, dorsal and anterior. Two K-wires are then placed in the tibia above the syndemosis in a converging way in accordance with the amount of correction that was preoperatively planned (MDTA angle) [27]. After that, the osteotomy is performed, and the gap is closed; the correction is stabilized with an angular stable plate. Finally, the position and length of the fibula is adjusted and secured with interfragmentary screws and a fibula plate [27]. See case example in Figure 2. Figure 2. Cont.