DEFINITION

Ankle arthritis is characterized by loss of joint cartilage and joint narrowing.

Primary ankle arthritis is relatively rare; most commonly, ankle arthritis is posttraumatic in origin. Inflammatory arthritides may also involve the ankle. Although ankle arthrodesis and total ankle arthroplasty are accepted surgical treatments for advanced ankle arthritis, joint-preserving supramalleolar osteotomy is an attractive alternative in select patients with advanced ankle arthritis, particularly in ankle

arthritis associated with malalignment.5,17,25,27,31,37

Supramalleolar osteotomy, whether opening or closing wedge, redistributes stresses on the ankle, transferring weight from an overloaded arthritic portion of the joint to a healthier aspect of the joint.6,29,32,34 In theory, realignment also improves the biomechanics of the lower extremity33 and may

improve function and delay the progression of the degenerative process. Despite the fact that the later

theoretical hypothesis sounds reasonable, Knupp et al11 demonstrated, using an experimental cadaveric model, that the isolated supramalleolar varus or valgus deformities did not inevitably lead to a medial or lateral overload, respectively. They concluded that the alterations of force transmission and intraarticular pressure in the ankle joint occur with the combined alteration in both the bony alignment and the

congruency of the ankle joint.11

 

ANATOMY

 

The ankle joint is the articulation formed by the mortise (tibial plafond-medial malleolus and the distal part of the fibula) and the talus.

 

The ankle is a modified hinge joint with a slight oblique orientation in two planes: (1) posterior and lateral in the transverse plane and (2) lateral and downward in the coronal plane.

 

This sagittal plane orientation affords about 6 degrees of rotation and 45 to 70 degrees in the flexion-extension motion arc.

 

The tibiotalar joint functions as part of the ankle-subtalar joint complex during gait; portions of the medial and lateral collateral ligaments cross both the ankle and subtalar joints. The blood supply is provided by the anterior and posterior tibial arteries and the peroneal artery as well as their branches and anastomoses, forming a rich vascular ring.

 

The distal tibial plafond is slightly valgus oriented, in the coronal plane, with respect to the tibial diaphysis, forming an angle called the tibial ankle surface (TAS) with a value of 93 degrees.16

 

The same angle in the sagittal plane, with its apex posteriorly, is called the tibial lateral surface (TLS), with a value of 80 degrees.16

PATHOGENESIS

 

Idiopathic (primary) arthritis, or osteoarthrosis, is relatively rare in the ankle. The exact mechanism of cartilage degeneration and loss has not been clearly defined, although several theories have been proposed.

 

Secondary arthritic involvement is mainly posttraumatic, occurring after intra-articular fractures, chondral or osteochondral injuries, and chronic instability.

 

Other causes of ankle arthritis include peripheral neuropathy (neuroarthropathy) and various inflammatory disorders (such as rheumatoid arthritis, mixed connective tissue disorders, gout, and pseudogout), primary synovial disorders (pigmented villonodular synovitis), and septic arthritis as well as seronegative arthritides associated with psoriasis, Reiter syndrome, and spondyloarthropathy.

 

Distal tibial deformity may be a result of malunion of a distal tibial or pilon fracture, physeal disturbance from adjacent osteochondromata, physeal dysplasia, and so forth.

 

NATURAL HISTORY

 

Untreated ankle arthritis typically progresses, with worsening pain that eventually interferes with daily activities. Gradually, ankle stiffness in addition to pain leads to a disturbance of physiologic heel-to-toe gait.

 

Low-demand patients with isolated ankle arthritis may function surprisingly well because of the adaptive effect of the healthy subtalar and transverse talar joints. However, obesity, high-demand activity levels, and concomitant subtalar or transverse tarsal joint pathology typically contribute to the morbidity of ankle arthritis.

 

To our knowledge, there are no absolute numbers for tibiotalar angular alignment that predispose an ankle to the development of arthritis. Several authors have reported that angulation exceeding 10 degrees was compatible with long-term normal function and absence of pain in the ankle joint,12,18 whereas biomechanical

studies on cadavers have shown that there is a decrease of the contact surface area in the ankle joint of up to

40% in the presence of malalignment,35,36 with the distal tibial deformities significantly altering total tibiotalar contact area, contact shape, and contact location.35

PATIENT HISTORY AND PHYSICAL FINDINGS

 

A complete examination of the ankle and hindfoot joints should include the following:

 

 

Soft tissue condition: previous scars, callosities, ulcers, fistulas, and so forth

 

Vascular status: peripheral pulses, microcirculation (capillary refill), ankle-brachial index

 

 

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Sensation: light touch and, if indicated, Semmes-Weinstein monofilament testing to rule out a peripheral neuropathy. A joint-preserving realignment supramalleolar osteotomy is feasible in select patients with peripheral neuropathy, but the potential for Charcot neuroarthropathy and failure of the procedure must be considered.

 

Stability: Anterior drawer test and inversion and eversion stress evaluations are performed to evaluate the integrity of the ankle and hindfoot ligaments. Realignment osteotomy with unstable or incompetent ankle or hindfoot ligaments may fail to improve function.

 

Motor strength: Manual motor testing of the major muscle groups is performed. Realignment in patients lacking essential motor function at the ankle will improve function in stance phase but will typically necessitate bracing for effective gait.

 

Alignment: The angle made by the Achilles and the vertical axis of the calcaneus is normally 5 to 7 degrees

of valgus. Altered alignment to varus or increased valgus position indicates either abnormal tilt of the talus within the ankle mortise (eg, unicompartmental cartilage wear) or abnormality of the subtalar joint.

 

Effusion testing: Elimination or fullness of the gutters indicates intra-articular fluid accumulation or hypertrophied capsular tissue.

 

Normal ankle and hindfoot range of motion (ROM) in the sagittal plane is 20 degrees of dorsiflexion to 50 degrees of plantarflexion. Normal values of hindfoot motion are difficult to measure because the motion is triplanar. A reasonable reference is 5 degrees of eversion and 20 degrees of inversion.

 

 

Isolated supramalleolar osteotomy for a stiff ankle rarely improves ROM; a stiff, diffusely arthritic and malaligned ankle may be best treated with realignment.

 

 

Hindfoot stiffness must also be documented. In patients with malaligned ankles, the hindfoot compensates. For example, a varus ankle will generally be associated with a compensating hindfoot in excessive valgus. If the hindfoot has lost its flexibility due to long-standing compensation for ankle malalignment, then supramalleolar osteotomy may realign the tibiotalar joint but create hindfoot malalignment. With a flexible hindfoot, this is generally not a problem.

 

IMAGING AND OTHER DIAGNOSTIC STUDIES

 

Weight-bearing anteroposterior (AP), lateral, and mortise ankle and foot radiographs determine the extent of arthritic involvement, deformity, bone defects in the distal tibial plafond or talus, and the presence of arthritis in the adjacent hindfoot articulations. Radiographs may also suggest avascular necrosis (AVN) of the talus or distal tibia.

 

With deformity, a minimum of full-length, weight-bearing AP and lateral tibial radiographs must be obtained. If more proximal deformity is suspected, then mechanical axis, fulllength hip-to-ankle radiographs should be considered to accurately plan realignment. More comprehensive full-length, weight-bearing radiographs are required to measure the TAS and TLS angles, the level of center of rotation of angulation (CORA) in case of existing deformity, and the preoperative leg length discrepancy because any substantial discrepancy may have an impact to the choice of osteotomy.

 

Diagnostic injection. If there is uncertainty over whether the pain is originating from the ankle or hindfoot, selective injections may be of use in distinguishing the source of pain.

 

DIFFERENTIAL DIAGNOSIS

Bone marrow edema Soft tissue pathology

Distal tibial plafond or talar AVN Osteochondritis

 

 

NONOPERATIVE MANAGEMENT

 

Nonoperative treatment of ankle arthritis includes pharmacologic agents, intra-articular corticosteroid injections, shoe wear modifications, and orthoses.

 

Nonsteroidal anti-inflammatory drugs (NSAIDs) are widely used and have proven efficacy in the management of arthritis, including ankle arthritis. In select patients with gastrointestinal irrigation, COX-2 inhibitors may offer a reasonable alternative to NSAIDs. Inflammatory arthritides are managed with immunosuppressive agents.

 

Judicious use of intra-articular corticosteroid injections may temporize inflammation associated with intraarticular ankle pathology. Moreover, initial injections of the ankle or hindfoot may serve a diagnostic purpose to distinguish ankle from hindfoot pain. Indiscreet use of corticosteroid injections may have a deleterious effect on the residual joint cartilage as a result of the steroid, the anesthetic, or perhaps the accompanying preservative.

 

Bracing to immobilize and support the arthritic ankle may provide some pain relief with weight bearing and ambulation. Specifically, polypropylene ankle-foot orthoses (AFOs), double metal upright braces, and lace-up braces, combined with the use of a stiff-soled rocker bottom shoe, may be of benefit. Bracing tibial and tibiotalar malalignment is challenging. With a flexible hindfoot, some axial realignment may be feasible, but correction is generally not possible at the focus of deformity.

 

SURGICAL MANAGEMENT

 

We use the supramalleolar osteotomy for the following indications2,3,30:

 

 

 

 

Realignment of distal tibia fracture malunion without or with mild osteoarthritic changes of the ankle joint Realignment of distal tibia malunion with mild to moderate osteoarthritic changes of the ankle joint Ankle fusion malunion

 

Ankle arthritis with deformity secondary to intra-articular trauma or AVN of the distal tibia

 

Correction of valgus deformity associated with a ball-andsocket ankle joint configuration secondary to tarsal coalition

 

Tibiotalar osteoarthritis resulting from chronic lateral ankle instability or a cavovarus foot deformity

 

Restoration of a plantigrade foot position in ankle deformity resulting from Charcot neuroarthropathy to create ankle and hindfoot alignment that may be safely braced

 

 

Correction of limb alignment in adolescents and young adults due to growth plate injury Correction of lower limb alignment as staged planning for a total ankle replacement

 

As a rule, we reserve supramalleolar osteotomy using internal fixation for mild to moderate angular deformities in the coronal or the sagittal plane. Severe angular deformities with concomitant translation of the distal segment or shortening are, in our opinion, better managed using external fixation and the principles of

Ilizarov.8,26

 

 

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Moreover, gradual correction of severe deformity with formation of a regenerate avoids large plates under a wound and typically thin soft tissues that would be under tension with acute correction using internal fixation.

 

Lee et al15 warned out that a supramalleolar osteotomy is indicated for the treatment of ankle osteoarthritis in patients with minimal talar tilt and neutral or varus heel alignment.

 

Comparing closing and opening wedge supramalleolar osteotomies: A closing wedge osteotomy may result in limb shortening when compared to opening wedge osteotomies. Conflicting reports exist regarding healing rates between the two methods. Studies suggest that closing wedge osteotomies exhibit delayed healing

when compared to opening wedge osteotomies,33 but other reports demonstrate more rapid healing using a closing wedge osteotomy.28,29,30 One advantage of a closing wedge osteotomy is that it does not necessitate incorporation of cancellous or structural interpositional graft. Although an opening wedge osteotomy may

preserve limb length, resultant skin tension from acute correction may create problems with wound healing and potential vascular compromise if the vessels are put on sudden stretch. Gradual correction with external fixation may be a safer option in cases with severe deformity.

 

In the absence of appreciable preoperative leg length discrepancy, we recommend correcting distal tibial varus deformities with a medial opening wedge osteotomy and valgus deformities with a medial closing wedge osteotomy.

 

Knupp et al10 reported that the decision for the type of osteotomy was based on the amount of correction needed. Thus, in the presence of severe varus deformities, the authors preferred a lateral closing osteotomy instead of a medial opening wedge because the fibula, in the late scenario, would restrict the potential for

adequate correction.10

 

Preoperative Planning

 

We routinely obtain bilateral, full-length, weight-bearing radiographs of the tibia including the knee and ankle joints.

 

We draw two lines on the preoperative radiographs: (1) the tibial mechanical axis (which for the tibia coincides with the anatomic axis) and (2) the distal tibial articular surface. On the AP view, the angle formed by these lines is the TAS angle (FIG 1). On the lateral view, these lines form the TLS angle.

 

Ideally, we define the physiologic TAS and TLS angles for each patient using radiographs of the healthy contralateral limb. The goal of surgery is to realign the TAS and TLS to physiologic values and perhaps add a few degrees of (slight) overcorrection to compensate for anticipated minor subsidence during healing of the osteotomy.

 

The full-length, weight-bearing radiographs serve to determine preoperative leg length discrepancy, which may influence the choice between opening and closing wedge osteotomies.

 

Determining the CORA of the deformity (see FIG 1): The CORA is the intersection of the two lines that define the deformity, lines that are drawn to represent the mechanical axes of the proximal (line A) and distal segments (line B).

 

With isolated angular deformity, the CORA is at the apex of the deformity. When translation is also present, the CORA is located proximal to the deformity.

 

In very distal tibial deformities or ankle deformities with minor to moderate alterations of the TAS angle, the CORA is at the level of the ankle joint line.

 

 

 

FIG 1 • Preoperative AP radiograph of a patient with severe valgus malalignment of the distal tibia, due to physeal disturbance from adjacent osteochondroma that was excised in a previous procedure. Note the location of center of rotation of angulation (CORA) at the intersection of two lines that represent the mechanical axes of the proximal (line A) and distal segments (line B). Line A, also representing the tibial mechanical axis (which in the case of the tibia coincides with the anatomic axis), and another line that is drawn to represent the distal tibial articular surface form the tibial ankle surface (TAS) angle on the AP view with a magnitude of 108 degrees.

 

 

With distal tibial procurvatum deformity (malunion) or ankle fusion malunion in equinus, the CORA is the intersection of the tibial mechanical axis and a line representing the ankle's center of rotation. Typically, in such cases, the CORA is the level of the lateral process of the talus.

 

Significance of the CORA: An osteotomy made at the level of the CORA, whether closing or opening, will predictably realign the ankle without translation of the distal segment and center of the ankle. If the osteotomy is not performed at the CORA, the center of the ankle will translate relative to the mechanical axis of the tibia, creating undesirable malalignment of the two segments and an unnecessary shift of loads to the ankle joint.

To avoid secondary translational deformity when the osteotomy is intentionally made at a different level than the CORA, the distal segment must be translated relative to the proximal segment. These osteotomy rules apply irrespective of the method of fixation chosen.23,24

 

The size of the opening wedge or closing wedge resection can be determined by drawing the desired correction angle on the preoperative radiographs and measuring the wedge size on a template, taking

magnification into account.1

 

The final step in preoperative planning is to determine the extent of compensation that is achieved by the subtalar joint before correction of the deformity. Deformities in the coronal plane are well compensated for by the subtalar joint, unless there is preoperative stiffness in the hindfoot.

 

For example, a varus deformity of the tibia is compensated for by eversion of the subtalar joint. In cases of chronic deformity, this attempt to compensate and maintain the foot plantigrade may become fixed at the subtalar joint. Moreover, other adaptive changes may occur including the transverse tarsal joint or midfoot, creating a fixed forefoot deformity. These secondary fixed deformities may also require surgical correction after the ankle is realigned in order to create a functional, plantigrade foot.

 

 

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Knupp et al10 grouped several types of asymmetric ankle arthritis into classes, depending on the degree of talar tilt in the ankle mortise, the degree of narrowing of the joint space, and the presence or not of anterior extrusion of the talus.

 

 

Their classification along with the proposed treatment algorithm are useful in the clinical practice by means of dictating the choice of type of supramalleolar osteotomy and any concomitant procedures as well as predicting the risk factors for treatment failure. Thus, according to their algorithm, a supramalleolar osteotomy should be biplane (including an anterior opening or posterior closing wedge) in cases with anterior talar extrusion, whereas in cases with talar tilt greater than 4 degrees, additional procedures, such

as soft tissue reconstruction, calcaneal osteotomy, and fibula osteotomy, are mandatory.10

 

Positioning

 

The supramalleolar osteotomy is performed with the patient supine.

 

A bump under the ipsilateral hip prevents the natural tendency of the lower extremity to fall into external rotation.

 

Approach

 

The fibular osteotomy is performed first, using a small lateral incision, protecting the lateral branch of the superficial peroneal nerve.

 

For the supramalleolar osteotomy, a medial skin incision is made and periosteal elevation is performed only to

the extent needed to perform the osteotomy.

TECHNIQUES

• Medial Closing Wedge Supramalleolar Osteotomy

Perform the fibular osteotomy first, using a small lateral incision. The osteotomy is oblique, located at the same level with the planned tibial cut. Some surgeons prefer to make the fibular osteotomy at a different level from the supramalleolar osteotomy.

We do not routinely apply fixation to the fibular osteotomy, except in cases where it is felt that additional stability is required.

When correcting tibial deformity, perform the osteotomy at the CORA (TECH FIG 1).

In select cases, the supramalleolar osteotomy is not performed at the CORA. In some distal tibial deformities, the CORA may be located at the ankle joint, where the osteotomy is not feasible,

34

 

and the translational component must be compensated. Also, in ankle deformity with only minor alterations of the TAS angle and when detrimental translation of the distal fragment is not a major concern, we generally perform the osteotomy 4 to 5 cm proximal to the medial malleolar tip.

 

 

 

TECH FIG 1 • Medial closing wedge supramalleolar osteotomy. A. Using a preoperative radiograph, the center of rotation of angulation (CORA) is located at the intersection of two lines that represent the mechanical axes of the proximal and distal segments. B. Under fluoroscopy, a Kirschner wire is inserted to the tibia perpendicular to the mechanical axis and a second Kirschner wire is inserted parallel to the ankle joint line intersecting the first wire, ideally at the apex of the deformity. C,D. Guide pin wires used to perform a closing medial wedge osteotomy. Pin A has been inserted to the tibia perpendicular to the mechanical axis and pin B has been inserted parallel to the ankle joint line, intersecting pin A at the apex of the deformity. E. The cut wedge. The pins have been used as a guide for the tibial cuts, whereas the size of the wedge has been determined during the preoperative planning. (continued)

 

 

 

TECH FIG 1 • (continued) F. Fluoroscopic view of the resected wedge. G. Fluoroscopic view of the closed osteotomy. H,I. Fluoroscopic AP and lateral views of the provisionally fixed osteotomy with Kirschner wires. J. Photo of the applied periarticular plate. Note the excellent fit on the distal tibia. K. The applied periarticular plate after completion of fixation with three screws in the distal segment. L. Fluoroscopic view of the osteotomy after completion of fixation.

 

 

We routinely use Kirschner wires to define our proposed osteotomy; for an opening wedge osteotomy, we use a single Kirschner wire, but for the medial closing wedge osteotomy, two Kirschner wires are required to define the tibial wedge resection. Under fluoroscopic guidance, insert the first Kirschner wire perpendicular to the mechanical axis and the second parallel to the ankle joint, intersecting the first Kirschner wire at the apex of the deformity. The size of the wedge has been determined during the preoperative planning, and the Kirschner wires are positioned 1 to 2 mm wider than the proposed osteotomy, so they can be left in place as a guide for the saw cuts. Although the Kirschner wires define the osteotomy in one plane, the surgeon must also orient the saw blade perpendicular to the tibial shaft axis when performing the osteotomy. With the anterior and posterior soft tissue and neurovascular structures protected, we routinely use a broad oscillating saw, constantly irrigating the blade with cooled

sterile saline or water to limit osteonecrosis. Ideally, a thin cortical bridge and periosteal sleeve on the opposite cortex will be preserved to allow for a greenstick-like closure of the osteotomy that facilitates maintenance of alignment and enhances stability. However, when the osteotomy is intentionally performed at a level different than that of CORA, then the opposite cortex must be violated to allow the distal segment to be translated.

 

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After removing the resected wedge and performing appropriate translation of the distal segment, close the osteotomy and provisionally fix it with Kirschner wires. The provisional fixation may be guidewires for intended cannulated screws or it must be positioned so as not to interfere with the definitive fixation.

Assess alignment of the tibia and ankle fluoroscopically, both in the AP and lateral planes.

 

Several dedicated low-profile periarticular plating systems for the distal tibia are marketed, both locking and nonlocking. The majority of these plates were designed for the contours of the physiologic tibia. With a wedge resection, the fit is typically acceptable but may not be perfect. Locking plates may provide optimal stability, but if the osteotomy is not fully closed, these may in fact delay or even hinder healing.

Nonlocking plates, in our opinion, allow for a small amount of settling at the osteotomy with weight bearing, potentially facilitating healing. (If additional stability is required, then cannulated or solid screws may be used from the tip of the medial malleolus across the osteotomy. Alternatively, a second plate may be added anteriorly on the tibia to provide rotational control to the tibia; however, this requires greater soft tissue dissection.)

 

We do not routinely apply fixation to the fibula, but if additional stability is required, then we apply a low-profile fibular plate.

 

Final fluoroscopic images in the AP and lateral planes confirm proper alignment, apposition of the osteotomy, and position of hardware.

• Medial Opening Wedge Supramalleolar Osteotomy

   

  Again, the osteotomy is ideally located at the level of the CORA (TECH FIG 2). If the CORA is located at the ankle joint level or if only minor correction is required and translation of the distal segment is of little concern, then we perform the osteotomy 4 to 5 cm proximal to the medial malleolar tip.

   

  We perform either a horizontal or slightly oblique (proximal medial to distal lateral) tibial osteotomy with a broad oscillating saw, preserving the opposite cortex and periosteal sleeve to serve as a fulcrum for the opening wedge and to enhance stability. If translation is necessary (the osteotomy is intentionally performed at a level different than that of CORA), then the opposite cortex is cut completely to allow the distal segment to move.

   

  Under fluoroscopy, gently distract the tibial osteotomy using a lamina spreader or alternative distraction system until desired correction is achieved.

   

  We routinely use contoured structural graft (generally, the neck portion of a femoral head allograft) to fill the osteotomy.

   

  After correcting the deformity, provisionally fix the osteotomy with Kirschner wires in a manner that does not interfere with the

   

  36

  definitive fixation. Assess the alignment using fluoroscopy, both in the AP and lateral planes.

   

   

   

  TECH FIG 2 • Medial opening wedge supramalleolar osteotomy. A. Using a preoperative radiograph, the center of rotation of angulation (CORA) is located at the intersection of two lines that represent the mechanical axes of the proximal and distal segments. B. Under fluoroscopy, a Kirschner wire is used to mark the osteotomy site at the CORA level. C,D. Under fluoroscopy, the tibial osteotomy is gently distracted using a lamina spreader until desired correction is achieved. (A,C,D: From Myerson MS. Osteotomy of the tibia and fibula. In: Reconstructive Foot and Ankle Surgery. Philadelphia: Elsevier, 2005:254.)

   

   

  Several dedicated low-profile periarticular plating systems for the distal tibia are marketed, both locking and nonlocking. The majority of these plates were designed for the contours of the physiologic tibia. With an opening wedge osteotomy, the fit is typically acceptable but may not be perfect. Locking plates may provide optimal stability, but if the osteotomy is not fully closed, these may in fact delay or even hinder healing. Nonlocking plates, in our opinion, allow for a small amount of settling at the osteotomy with weight bearing, potentially facilitating incorporation of the interpositional graft. (If additional stability is required, then cannulated or solid screws may be used from the tip of the medial malleolus across the osteotomy. Alternatively, a second plate may be added anteriorly on the tibia to provide rotational control to the tibia; however, this requires greater soft tissue dissection.)

• Wound Closure

   

  After completing the fixation, close the wound routinely in layers. With opening wedge osteotomies, the skin tension is typically greater than before surgery, but with longitudinal incisions, this is rarely problematic. Use of a drain is at the discretion of the surgeon; we do not routinely use a drain.

   

  PEARLS AND PITFALLS

   

  Fixation ▪ We recommend internal fixation for supramalleolar osteotomies in mild to moderate corrections. Complex and severe deformity may be best managed with external fixation and Ilizarov principles. Multiplanar correction with external fixation effectively manages angular and translational deformity and simultaneously compensates for potential loss of limb length. If there is no significant preoperative leg length discrepancy, then all varus deformities are corrected using a medial opening wedge osteotomy, whereas the valgus deformities are corrected with a medial closing wedge osteotomy.

   

  Exposure ▪ Minimal periosteal elevation preserves vascularity at the osteotomy site.

   

  Osteotomy level

• A closing or opening wedge osteotomy at the level of the CORA will lead to complete realignment of the foot and ankle. If the osteotomy is made proximal or distal to the CORA, the distal segment and center of the ankle will translate relative to the mechanical axis of the tibia. When the osteotomy must be performed at a level different than the CORA, then the osteotomy must be completed on the lateral cortex and translated along with the angular correction. These osteotomy rules apply irrespective of the method of fixation chosen.

   

  Fixation of the osteotomy

• In our experience, medial plating is typically adequate for fixation of opening or closing wedge supramalleolar osteotomies. However, additional stability may be gained with (1) screws from the tip of the medial malleolus that cross the osteotomy or (2) supplemental anterior plating. No fixation is applied to the fibular osteotomy, except in cases where it is felt that additional stability is required.

   

  Graft choice

  • The graft alternatives are to harvest it from the ipsilateral iliac crest or the proximal

    tibia or to use tricortical allograft.4 The two basic types of bone grafts are structural and cancellous. A structural bone graft is one that alters the shape during a reconstruction procedure by virtue of its size and dimension. The structural bone graft provides immediate mechanical support, with little likelihood of collapse even after the resorption that occurs during revascularization. Some structural integrity remains during the process of bone graft incorporation to allow the graft to withstand loads.

     

    Locked versus nonlocked plates

• Locked plating affords optimal stability; however, if the plate is locked with suboptimal bony contact at the osteotomy site, then there may be a delay in osteotomy healing or incorporation of a structural graft. Nonlocked plating permits some settling during weight bearing that may promote healing of the osteotomy, provided stability is satisfactory.

 

POSTOPERATIVE CARE

 

The procedure may be performed on an outpatient basis, but we routinely keep the patient overnight for monitoring and pain control (23-hour observation status).

 

Although rare, a tibial osteotomy, albeit distal to the lower leg muscles, could potentially create a compartment syndrome, and therefore overnight monitoring is prudent. All patients are discharged with a non-weight-

bearing postoperative splint, are instructed to maintain elevation of the extremity, and are to return to the clinic 2 weeks after surgery for suture removal.

 

At 2 weeks, we routinely place the patient in a removable, prefabricated cam walker boot. If we have concern for the osteotomy stability or patient compliance, we obtain radiographs at this time to ensure satisfactory alignment and fixation, and place the patient into a short-leg non-weight-bearing cast.

 

 

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The patient returns at 6 weeks from surgery, at which time we routinely obtain simulated weight-bearing radiographs of the ankle. Depending on the stability of fixation and evidence for progression toward healing, we allow the patient to progressively advance weight bearing in the cam walker boot.

 

Typically, with follow-up at 10 weeks from surgery, full weight bearing is permitted in the cam walker boot, with a rapid transition to a regular shoe, provided that weightbearing radiographs of the ankle suggest satisfactory healing. Early ROM exercises without resistance are initiated early (at 2 weeks), when osteotomy fixation is

deemed stable and if there is no concomitant procedure13 (eg, ligament reconstruction or tendon transfer) dictating adjustment of the rehabilitation protocol.

 

OUTCOMES

Several studies have shown that the overall outcome of supramalleolar osteotomy is very good in terms of pain relief, correction of any existing mechanical malalignment, and the arresting of arthritic changes in the ankle joint.6,7,9,14,19,20,21,22,29,32,33

The type of osteotomy (opening vs. closing wedge) does not influence the final outcome, even though a closing wedge osteotomy may lead to leg length discrepancy or decreased strength.29

The type of osteotomy (opening vs. closing wedge) has no influence on the time of osseous healing.29

 

 

COMPLICATIONS

Nonunion Delayed union

Over- or undercorrection of the deformity Decreased postoperative ROM

Failure to perform the osteotomy at the level of CORA, thus translating the distal fragment and center of the ankle away from the mechanical axis

Failure to perform the appropriate translation of the distal segment, in cases where the osteotomy is intentionally performed at a different level than that of CORA (such as when the CORA is at the level or distal to the ankle joint), leading to mechanical axis shifting

 

 

ACKNOWLEDGMENT

 

I would like to thank my mentor Mark S. Myerson for his enlightening training, friendship, and help for the preparation of this chapter.

 

REFERENCES

1. Acevedo JI, Myerson MS. Reconstructive alternatives for ankle arthritis. Foot Ankle Clin 1999;4:409-430.

    

    

2. Becker AS, Myerson MS. The indications and technique of supramalleolar osteotomy. Foot Ankle Clin 2009;14:549-561.

    

    

3. Benthien RA, Myerson MS. Supramalleolar osteotomy for ankle deformity and arthritis. Foot Ankle Clin 2004;9:475-487.

    

    

4. Borrelli J Jr, Leduc S, Gregush R, et al. Tricortical bone grafts for treatment of malaligned tibias and fibulas. Clin Orthop Relat Res 2009;476:1056-1063.

    

    

5. Chao KH, Wu CC, Lee CH, et al. Corrective-elongation osteotomy without bone graft for old ankle fracture with residual diastasis. Foot Ankle Int 2004;25:123-127.

    

    

6. Graehl PM, Hersh MR, Heckman JD. Supramalleolar osteotomy for the treatment of symptomatic tibial malunion. J Orthop Trauma 1987;1:281-292.

    

    

7. Hintermann B, Knupp M, Barg A. Osteotomies of the distal tibia and hindfoot for ankle realignment [in German]. Orthopaede 2008;37:212-218, 220-223.

    

    

8. Horn DM, Fragomen AT, Rozbruch SR. Supramalleolar osteotomy using external fixation with six-axis deformity correction of the tibia. Foot Ankle Int 2011;32:986-993.

    

    

9. Knupp M, Pagenstert G, Valderrabano V, et al. Osteotomies in varus malalignment of the ankle [in German]. Oper Orthop Traumatol 2008;20:262-273.

    

    

10. Knupp M, Stufkens SA, Bolliger L, et al. Classification and treatment of supramalleolar deformities. Foot Ankle Int 2011;32:1023-1031.

     

     

11. Knupp M, Stufkens SA, van Bergen C, et al. Effect of supramalleolar varus and valgus deformities on the tibiotalar joint: a cadaveric study. Foot Ankle Int 2011;32:609-615.

     

     

12. Kristensen KD, Kiaer T, Blicher J. No arthrosis of the ankle 20 years after malaligned tibial-shaft fracture. Acta Orthop Scand 1989;60:208-209.

     

     

13. Lee HS, Wapner KL, Park SS, et al. Ligament reconstruction and calcaneal osteotomy for osteoarthritis of the ankle. Foot Ankle Int 2009;30:475-480.

     

     

14. Lee KB, Cho YJ. Oblique supramalleolar opening wedge osteotomy without fibular osteotomy for varus deformity of the ankle. Foot Ankle Int 2009;30:565-567.

     

     

15. Lee WC, Moon JS, Lee K, et al. Indications for supramalleolar osteotomy in patients with ankle osteoarthritis and varus deformity. J Bone Joint Surg Am 2011;93:1243-1248.

     

     

16. Mangone PG. Distal tibial osteotomies for the treatment of foot and ankle disorders. Foot Ankle Clin 2001;6:583-597.

     

     

17. Marti RK, Raaymakers EL, Nolte PA. Malunited ankle fractures. J Bone Joint Surg Br 1990;72(4):709-713.

     

     

18. Merchant TC, Dietz FR. Long-term follow-up after fractures of the tibial and fibular shafts. J Bone Joint Surg Am 1989;71(4):599-606.

     

     

19. Neumann HW, Lieske S, Schenk K. Supramalleolar subtractive valgus osteotomy of the tibia in the management of ankle joint degeneration with varus deformity [in German]. Oper Orthop Traumatol 2007;19:511-526.

     

     

20. Pagenstert G, Knupp M, Valderrabano V, et al. Realignment surgery for valgus ankle osteoarthritis. Oper Orthop Traumatol 2009;21: 77-87.

     

     

21. Pagenstert G, Leumann A, Hintermann B, et al. Sports and recreation activity of varus and valgus ankle OA before and after realignment surgery. Foot Ankle Int 2008;29:985-993.

     

     

22. Pagenstert GI, Hintermann B, Barg A, et al. Realignment surgery as alternative treatment of varus and valgus ankle osteoarthritis. Clin Orthop Relat Res 2007;462:156-168.

     

     

23. Paley D. The correction of complex foot deformities using Ilizarov's distraction osteotomies. Clin Orthop Relat Res 1993;(293):97-111.

     

     

24. Paley D, Herzenberg JE, Tetsworth K, et al. Deformity planning for frontal and sagittal plane corrective osteotomies. Orthop Clin North Am 1994;25:425-465.

     

     

25. Perera A, Myerson M. Surgical techniques for the reconstruction of malunited ankle fractures. Foot Ankle Clin 2008;13:737-751.

     

     

26. Rozbruch SR, Fragomen AT, Ilizarov S, et al. Correction of tibial deformity with use of the Ilizarov-Taylor spatial frame. J Bone Joint Surg Am 2006;88:156-174.

     

     

27. Sinha A, Sirikonda S, Giotakis N, et al. Fibular lengthening for malunited ankle fractures. Foot Ankle Int 2008;29:1136-1140.

     

     

28. Stamatis E, Myerson M. Supramalleolar osteotomy for the treatment of distal tibial angular deformities and arthritis of the ankle joint. Tech Foot Ankle Surg 2004;3:138-142.

     

     

29. Stamatis ED, Cooper PS, Myerson MS. Supramalleolar osteotomy for the treatment of distal tibial angular deformities and arthritis of the ankle joint. Foot Ankle Int 2003;24:754-764.

     

     

30. Stamatis ED, Myerson MS. Supramalleolar osteotomy: indications and technique. Foot Ankle Clin

    2003;8:317-333.

     

     

31. Swords MP, Nemec S. Osteotomy for salvage of the arthritic ankle. Foot Ankle Clin 2007;12:1-13.

     

     

    38

     

32. Takakura Y, Takaoka T, Tanaka Y, et al. Results of opening-wedge osteotomy for the treatment of a post-traumatic varus deformity of the ankle. J Bone Joint Surg Am 1998;80(2):213-218.

     

     

33. Takakura Y, Tanaka Y, Kumai T, et al. Low tibial osteotomy for osteoarthritis of the ankle: results of a new operation in 18 patients. J Bone Joint Surg Br 1995;77(1):50-54.

     

     

34. Tanaka Y, Takakura Y, Hayashi K, et al. Low tibial osteotomy for varus-type osteoarthritis of the ankle. J Bone Joint Surg Br 2006;88(7):909-913.

     

     

35. Tarr RR, Resnick CT, Wagner KS, et al. Changes in tibiotalar joint contact areas following experimentally induced tibial angular deformities. Clin Orthop Relat Res 1985;(199):72-80.

     

     

36. Ting AJ, Tarr RR, Sarmiento A, et al. The role of subtalar motion and ankle contact pressure changes from angular deformities of the tibia. Foot Ankle 1987;7:290-299.

     

     

37. Weber D, Friederich NF, Müller W, et al. Lengthening osteotomy of the fibular for post-traumatic malunion: indications, technique and results. Int Orthop 1998;22:149-152.