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Review Article

Management of Extra-articularDeformity in the Setting of TotalKnee Arthroplasty

Abstract

Extra-articular deformities of the femur and tibia in conjunction withadvanced knee osteoarthritis pose unique challenges for thearthroplasty surgeon. Careful preoperative planning is needed toevaluate both the intra- and extra-articular deformities and todetermine the best route to total knee arthroplasty. An intra-articularcompensatory correction can typically be performed if the extra-articular deformity is distant from the joint or if preoperative templatingshows that bony cuts do not interfere with ligamentous attachments.Staged osteotomy followed by arthroplasty is beneficial in severecases in which bony cuts are excessive or would interfere with soft-tissue structures and in cases with leg-length discrepancy.Osteotomies can be performed percutaneously and fixed withintramedullary nails, external fixators, or plate and screw constructs.Ligamentous laxity after correction and risk of peroneal nerve injuryare increased in extra-articular deformity cases and must beconsidered during the knee arthroplasty procedure with increasedimplant constraint and patient counseling, respectively. Computer-assisted navigation has an emerging role in total knee arthroplasty inpatients with extra-articular deformity.

More than 700,000 total kneearthroplasties (TKAs) are per-

formed annually in the United States.1

Although correction of intra-articularpathology is a mainstay of TKA, lesshas been published on the evaluationand management of extra-articulardeformity in the setting of TKA. Anextra-articular deformity may be aresult of previous trauma or skele-tal developmental abnormalities andmay increase the risk of knee osteo-arthritis.2 Thus, orthopaedic surgeonsshould be aware of the diagnosis andtreatment algorithms for extra-articular deformity in the setting ofTKA. Performing a TKA withoutaddressing underlying extra-articularmalalignment may place the patient at

risk of ongoing pain and early implantfailure.3 The purpose of this article isto present treatment algorithms forthe management of extra-articulardeformity in either the femur ortibia and in the coronal, sagittal, oraxial plane and to review the radio-graphic imaging, surgical planning,and multidisciplinary approach nec-essary to optimize clinical outcomesand minimize arthroplasty failure.

Causes of Extra-articularDeformity of the Femur andTibia and Its AssociationWith Knee Osteoarthritis

Causes of extra-articular deformityof the femur and tibia are numerous

Peter K. Sculco, MD

Cynthia A. Kahlenberg, MD

Austin T. Fragomen, MD

S. Robert Rozbruch, MD

From the Adult Reconstruction andJoint Replacement Service(Dr. Sculco), the Department ofOrthopaedic Surgery(Dr. Kahlenberg), and LimbLengthening and ComplexReconstruction Service(Dr. Fragomen and Dr. Rozbruch),Hospital for Special Surgery, NewYork, NY.

J Am Acad Orthop Surg 2019;00:1-12

DOI: 10.5435/JAAOS-D-18-00361

Copyright 2019 by the AmericanAcademy of Orthopaedic Surgeons.

Month 2019, Vol 00, No 00 1

Copyright � the American Academy of Orthopaedic Surgeons. Unauthorized reproduction of this article is prohibited.

http://dx.doi.org/10.5435/JAAOS-D-18-00361

and can lead to varying degrees ofdeformity. Specific causes includemetabolic bone diseases, congenitalabnormalities, posttraumatic malunion,and previous osteotomies.4 Fracturemalunion of the femur and/or tibia, oneof the most common causes of extra-articular deformities around the knee,5

may cause altered knee kinematics andasymmetric compartmental forcesrelated to the deformity and resultantmechanical axis deviation (MAD)that may lead to early degenerativechanges in the knee joint.6,7 However,the direct link between fracture mal-union and knee osteoarthritis has beenquestioned because a study of femoralshaft malunions with more than 20years of follow-up did not find anassociation between femur malunionand knee osteoarthritis.8 The severityof the deformity, not the malunionitself, is likely the most importantdeterminant of overall knee functionand risk of osteoarthritis progression.In a study of 237 patients with kneeosteoarthritis, Sharma et al2 noted thatmore than 5� of varus or valgusdeformity had a five times greater riskof osteoarthritis progression over an18-month period compared withneutral controls. In addition, theyfound that the magnitude ofmechanical malalignment correlatedwith a decline in physical function andincrease in osteoarthritis. These lon-gitudinal studies demonstratingincreasing osteoarthritis progression,particularly with mechanical deform-ities greater than 5�, suggest thatuntreated fracture malunions mayrequire TKA at a higher rate thannormal controls. For this reason, it islikely that joint arthroplasty surgeonswill encounter patients with extra-

articular deformities and end-stageosteoarthritis necessitating TKA, andappropriate management of these de-formities at the time of TKA is criticalto a successful clinical outcome.Another cause of extra-articular

deformity about the knee is con-genital or metabolic bone diseases.5

These include osteogenesis imperfecta,causing a bony bowing or thinningdeformity, Blount disease, causingvarus deformity of the proximal tibiaand distal femur, and hereditary hy-pophosphatemia or hyperparathy-roidism, which lead to worsened bonequality and a variety of deformities.Tumors, both benign and malignant,are another cause of extra-articulardeformity. Tumors themselves, andthe medications used in the manage-ment of tumors, can lead to worsenedbone quality and deformity and shouldbe treated in consultation with atumor surgeon. Finally, Paget diseaseof bone occurs from a disorganizedbony deposition that causes the boneto become sclerotic and thickened.Associated deformities include distalfemoral valgus and anterior bow-ing of the tibia. Patients with Pagetdisease are also at risk of increasedblood loss during surgery, andadvanced planning should be donefor these patients before theyundergo TKA.5

Radiographic Evaluation

Long leg hip-to-ankle radiographs inthe AP and lateral planes are essentialfor accurate preoperative planningand assessment of an extra-articulardeformity.Alghamdi et al9 noted thatmore than 50% of extra-articular

deformities of the tibia are not de-tected on short films of the knee. Weroutinely obtain full-length radio-graphs for all TKA patients to eval-uate the deformity and allow forappropriate preoperative planning.10

Although positioning can be difficultin cases of severe deformity, everyattempt should be made to positionthe patient in an anatomic fashion.Correlation should be made betweenthe physical examination and thepositioning of the radiographic im-ages. Several measurements aremade on the calibrated full-lengthstanding radiographs to evaluate thelocation and extent of deformity(Table 1).

Coronal PlaneMeasurementsIn the coronal plane, the MAD isused to evaluate for varus or valgusdeformity. The lateral distal femoralangle (LDFA) and the medial proxi-mal tibial angle (MPTA) determinewhether the deformity is originatingfrom the femur, the tibia, or both.Thejoint line convergence angle indicatesthe amount of deformity comingfrom within the joint. The center ofrotation of angulation (CORA) isuseful to determine the distance of thedeformity from the joint and can beused if osteotomy planning is beingconsidered.

Sagittal and Axial PlaneMeasurementsThe posterior distal femoral angleand the posterior proximal tibialangle are the primarymeasurementsused to evaluate the degree ofdeformity in the sagittal plane.

Dr. Sculco or an immediate family member has received research support from Intellijoint. Dr. Fragomen or an immediate family member is amember of a speakers’ bureau or has made paid presentations on behalf of NuVasive, Smith & Nephew, and Synthes; serves as a paidconsultant to Globus Medical, NuVasive, Smith & Nephew, and Synthes; and serves as a board member, owner, officer, or committeemember of the Limb Lengthening Research Society. Dr. Rozbruch or an immediate family member has received IP royalties from Stryker;is a member of a speakers’ bureau or has made paid presentations on behalf of NuVasive, Smith & Nephew, and Stryker; serves as a paidconsultant to NuVasive and Stryker; and serves as a board member, owner, officer, or committee member of the Limb Lengthening andReconstruction Society. Neither Dr. Kahlenberg nor any immediate family member has received anything of value from or has stock or stockoptions held in a commercial company or institution related directly or indirectly to the subject of this article.

Extra-articular Deformity in Total Knee Arthroplasty

2 Journal of the American Academy of Orthopaedic Surgeons


Measurements should be madepreoperatively, and any deviationfrom the normal range should beconsidered in preoperative planning.The CORA can also be determinedand used to determine osteotomyplanning in the sagittal plane. Foraxial plane malalignment, a CT scancan also be used to determine fem-oral version12 and should be ob-tained in cases of concern for axialmalalignment.

Leg-Length MeasurementsLimb-length discrepancy (LLD)should also be measured and consid-ered in planning for TKA, but thepatient should be advised that anLLD may persist after TKA. Radio-graphically, standing full-lengthradiographs are an accurate andreproducible method for evaluatingLLD. The true, or structural, limb-length difference is the distance from

the top of the femoral head to thecenter of the ankle joint on each limb.Separate measurements of the femurand the tibia can be useful in deter-mining the source of the structuralLLD. Functional measurement ofLLD can be performed from theumbilicus to the medial malleo-lus.13,14 A clinical measurement of apatient’s functional LLD can beperformed by placing blocks ofvarying heights under the shorter

Table 1

Radiographic Measurements for Preoperative Assessment of Deformity11

Measurement DescriptionNormalRange Clinical Significance

Coronal planemeasurements

MAD Measured by drawing a line from thecenter of the femoral head to the centerof the ankle and drawing a second linefrom the center of the tibial spines tomeet the first line

0-8 mmmedial

Any line that is drawn laterally isconsidered a valgus deformity, and anyline greater than 8 mm medial isconsidered a varus deformity

LDFA Angle betweena line from the center of thehip to thecenterof thekneeandasecondline connecting the femoral condyles

85�-90� Angle outside of normal range indicatesdeformity originating from the femur

MPTA Angle between a line down the shaft ofthe tibia and a line across the top of thetibial condyles

85�-90� Angle outside of normal range indicatesdeformity originating from the tibia

JLCA Angle between a line drawn across thetibial condyles and a line across thefemoral condyles

0�-2� Angle greater than normal rangeindicates deformity originating frominside the joint, either from cartilageloss or ligamentous instability

Sagittal planemeasurements

PDFA Angle between the sagittal distal femoraljoint line and the mid-diaphyseal line ofthe femur

79-83 Angle outside of the normal rangeindicates a sagittal plane deformity ofthe femur

PPTA Angle between the sagittal tibial joint lineand the mid-diaphyseal line of the tibia

77-84 Angle outside of the normal rangeindicates a sagittal plane deformity ofthe tibia

Axial planemeasurements

LLD Distance measured from the top of thefemoral head to the center of the anklejoint on each limb

NA Any discrepancy should be noted andaccounted for in the correction of thedeformity

Deformitymeasurements

CORA Location where the anatomic axes of thebone proximal to the deformity anddistal to the deformity meet

NA Often used as the basis for where to planthe osteotomy if corrective surgery isbeing considered

CORA = center of rotation of angulation, JLCA = joint line convergence angle, LDFA = lateral distal femoral angle, LLD = limb-length discrepancy,MAD =mechanical axis deviation, MPTA =medial proximal tibial angle, NA = not applicable, PDFA = posterior distal femoral angle, PPTA = posteriorproximal tibial angle

Peter K. Sculco, MD, et al

Month 2019, Vol 00, No 00 3


limb until the patient feels leg lengthsto be equal.13

Preoperative Templatingfor Total Knee ArthroplastyWith Extra-articularDeformity

Preoperative planning for TKA incases of extra-articular deformity inthe femur, tibia, or both shouldinclude (1) themagnitude (in degrees)of the extra-articular deformity and(2) the location of the deformity(CORA) in relation to the knee joint.The location of the CORA de-termines surgical treatment becauseas the CORA moves further away

from the knee joint, its effect onoverall mechanical alignment de-creases and the deformity becomeseasier to address with TKA alone.4

For example, a deformity of the samemagnitude just a few centimetersfrom the knee joint may require asubstantial correction, whereas alarger deformity farther away fromthe knee joint may have a minimaleffect on bone resections and bal-ancing of the TKA (Figure 1). Wolffet al4 used geometric calculations toshow that the magnitude of defor-mity increases linearly as it getscloser to the joint. They showed thatfor the same 20� extra-articulardeformity, with every 10% of over-

all femur or tibia length that thedeformity moved closer to the joint,an additional 2� of overall limbmalalignment would be present.4

Furthermore, LDFA and MPTAmeasurements should be analyzed asfurther deviations from normalmeasurements and should be incor-porated into the preoperative plan-ning for the correction.

Preoperative Planning forTotal Knee Arthroplasty: TheCoronal PlaneA key component of preoperativeplanning in the coronal plane isdetermining the location of distalfemoral andproximal tibial bone cuts

Figure 1

Radiographs demonstrating the effects of deformity near and far from the knee joint. A, A large deformity near the knee jointhas a severe effect on angulation at the knee joint. Anatomic axes and mechanical axis are shown. Severe deviation of themechanical axis is noted. B, View of the same patient’s knee showing the tibial deformity. C, A deformity of the samemagnitude further away from the knee joint has less of an effect on angulation at the knee joint.




in relation to the insertion sites of thecollateral ligaments because this willdetermine whether the correction isachievable with TKA alone or if os-teotomies are needed before TKA.Previous studies have reported thatan intra-articular compensatory cor-rection can usually be achieved withTKA if the extra-articular deformityis ,20� in the coronal plane on thefemoral side or ,30� on the tibialside when the CORA is locatedoutside the metaphyseal region.11,15-17

For deformities of greater severity ordeformities close to the joint, an extra-articular osteotomy may be needed toachieve a well-aligned TKA. Femoral-sided deformities are less well toler-ated than tibial deformities in thecoronal plane because a corrective cutof the distal femur will change thebalance of the knee only in extension,whereas a corrective cut on the tibialside will change the balance of theknee equally in flexion and extension.18

Therefore, intra-articular correction ofan extra-articular femoral-sided defor-mity may lead to an unbalanced kneedue to flexion-extension gap imbalance.As previously mentioned, the thresh-old for performing an isolated intra-articular compensatory correction witha TKA is based on angular severity,CORAdistance from the joint line, andconcomitant sagittal plane deformity.As angular severity increases andCORA is in close proximity, theextent of soft-tissue releases necessaryto achieve a well-balanced knee in-creases along with the need for eitheran unlinked constrained or linkedconstrained (hinge) device.19

Wang and Wang16 describedanother simple methodology to de-termine whether the coronal planemalalignment is correctable with TKAalone or if osteotomies are needed.The mechanical axis of the femur isdrawn first from the center of thefemoral head to the center of thefemoral notch. A second line is thendrawn perpendicular to the mechani-cal axis line at the proposed level of

the femoral resection. If the perpen-dicular line (proposed femoral boneresection) passes distal to the in-sertions of the collateral ligaments (onaverage 25 mm proximal to the jointline), an intra-articular correction isfeasible. If the proposed femoral boneresection compromises the collateralligament insertion, an extra-articularcorrection must be performed beforeTKA (Figure 2). For the tibia, a line isdrawn from the center of the talus upthe shaft of the tibia in the distalfragment of the deformed bone. Wangand Wang reported that if this linepasses through the top of the tibialplateau, correction with primaryarthroplasty is feasible. However,larger tibial corrections may requirebone grafting, extensive releases, andconstrained implants. If the tibialbone resection is too radical or notpossible with conventional implants, acorrective tibial osteotomy should beperformed before arthroplasty.16,18,20

It is often helpful to draw a line per-pendicular to the mechanical axis toestimate the exact tibial resection thatwill be performed.Wang and Wang16 applied their

coronal plane planning methodologyto a series of 15 patients with fracturemalunions causing extra-articulardeformity of the femur or tibia. Pre-operative planning predicted that anintra-articular correction would bepossible. In the case series, the meanpreoperative femoral deformity was15� in the coronal plane and 8� in thesagittal plane. The mean tibial defor-mity was 19� in the coronal plane. Allpatients underwent primary TKA, andthemean postoperativemechanical axisangle was 0.3� varus. They reported amean Knee Society Score improve-ment from 22.3 to 91.7 at a mean of38 months postoperatively and nocomplications in the patient cohort.Preoperative planning should also

include an assessment of stem or keelfit on the tibia and stemfit on the femur.Implants should be chosen preopera-tivelyand if stemmed implantsarebeing

used, thismustbe includedaspartof thepreoperative template. In cases inwhichintra-articular correction can be

Figure 2

Radiograph of a 50-year-old womanwith previous trauma to left lowerextremity demonstrating preoperativetemplating bony cuts for correction ofextra-articular deformity. Ninety-degree cuts are drawn on the tibiaand femur to template for TKA.Preoperative planning shows anacceptable distal femoral cut. On thetibial side, if a 10 mm cut is taken fromthe lateral side, a large medial defectwould be present. If a 90� cut wasmade with a 2 mm taken off the medialside, the lateral tibial cut would beexcessive. Options in this case includecorrective osteotomy versus cutting10 mm of bone from the lateral sideand filling the large medial defect withgraft, cement, or augment. In this case,the authors would favor a correctivetibial osteotomy, followed by primaryTKA, without the need for augmentingthe defect. TKA = total kneearthroplasty


Month 2019, Vol 00, No 00 5


achieved but stems or keels will not fitbecause of an extra-articular defor-mity, consideration should be givento either switching implants orperforming a corrective osteotomybefore TKA to avoid complicationsintraoperatively.

Preoperative Planning forTotal Knee Arthroplasty:Sagittal PlaneSagittal plane deformity is typicallybetter tolerated than coronal plane

deformity in the setting of patientsundergoing TKA.19,21 The literatureis limited on this topic, but previousstudies have reported that an intra-articular correction with TKA isfeasible if a procurvatum deformityis less than 10� or a recurvatumdeformity less than 20�.19 Toleranceof recurvatum deformity is greaterthan that of procurvatum deformitybecause of the risk of femoralnotching with a procurvatum extra-articular deformity. In recurvuatum,it is possible to correct a larger sag-

ittal deformity with a TKR withoutnotching the anterior femoral cortex(Figure 3). Other authors havereported the successful intra-articularcorrection of sagittal plane deformityof up to 15� for either recurvatum orprocurvatum.21 Although no absolutedegree of sagittal malalignment exists,generally guidelines suggest that whenthe sagittal deformity (either pro-curvatum or recurvatum) is greaterthan 20�, an osteotomy should beperformed before TKA. In the settingof a sagittal deformity that is com-bined with a coronal plane defor-mity, hexapod frames are a usefultool that can be used to graduallycorrect the deformity in multipleplanes22,23 (Figure 4).

Preoperative Planning forTotal Knee Arthroplasty:Rotational DeformityPreoperative awareness and planningfor an axial plane deformity is alsoimportant for a successful outcome ofTKA. Rotational deformity may beevaluated clinically during examina-tion of a patient’s gait by assessingfor asymmetry in foot progres-sion angle between the normal andmalaligned limb.24 Hip range ofmotion, particularly internal andexternal rotation, should be as-sessed, and significant differencesbetween the normal and affected sideshould raise suspicion for rotationabnormalities involving the hip.Plain radiographs may demonstratesubluxation of the patella in thetrochlea groove, which may alsoindicate a rotational abnormality.Any rotational abnormality notedon examination of plain radio-graphs should be further evaluatedwith cross-sectional imaging, typicallya CT version study of the lowerextremity.Unfortunately, TKA allows for

minimal correction of rotationaldeformity.Wang et al21 reported in aseries of patients undergoing TKA

Figure 3

Radiographs of a 59-year-old man, who presented with right knee pain after afemoral fracture 40 years prior, demonstrating femoral recurvatum deformity (A).Computer navigation (Orthoalign) was used for alignment of the femoral cuttingguide. Neutral alignment was obtained in both the coronal and sagittal planesusing standard primary TKR implants (B).




with a history of femoral fracturemalunion and severe internal rotationof the femur leading to unavoidablenotching of the anterior-lateral fem-oral cortex during the TKA. Theyrecommended the use of a wedgecancellous bone graft in the notchedarea in these cases. With femoralmalunion and excessive externalrotation of the distal femur, no spe-cial challenges were encountered atthe time of TKA.21 Rotational de-formities are a challenging issuefacing the arthroplasty surgeon. Wedo not recommend attempting tocorrect a rotational deformity at thetime of TKA. Instead, the seniorauthors prefer to correct any rota-tional deformity in a separate stagedprocedure before TKA to avoidcomplications during the arthro-plasty procedure.

Preoperative Planning forTotal Knee Arthroplasty:Limb-Length DiscrepancyExtra-articular deformity in patientsseeking TKA can also be associatedwith an LLD, usually shortening of theaffected limb. In cases of both LLDand deformity, intramedullary internallengthening nails (ILNs) can simulta-neously correct both problems25-28

(Figure 5). When using an ILN beforeor simultaneously with a TKA, thesurgeon must be aware of the deform-ities that ILNs can create as theylengthen. Thinner-diameter ILNs have atendency to bend into varus, whereasstiffer nails are more likely to create avalgus deformity as they lengthen alongthe anatomic axis. Blocking screws areespecially useful for allowing for cor-rection of coronal or sagittal deformity

with ILNs. Care must be taken toavoid impingement of blocking screwsonto the ILN that will prevent the nailfrom lengthening appropriately.29

Kim et al30 reported the effect ofuncorrected leg-length discrepancyon the outcome of TKA. They foundthat a postoperative LLD of.15 mmwas associated with markedly lowerscores on both the Knee Societyfunctional score and the ascendingstairs parameter of the WOMACscore. However, no difference wasfound in patient satisfaction results.

Treatment Principles forCorrection of Extra-articular Deformity

The surgical treatment options for cor-rection of an extra-articular deformity

Figure 4

Radiographs of a 50-year-old woman, who sustained multiple fractures when she was a pedestrian struck by a motor vehicle30 years before presentation, demonstrating tibial varus and recurvatum deformities. She incurred a malunion of the leftproximal tibial shaft. She reported pain and knee stiffness. The radiographs demonstrated 29� of recurvatum deformity extra-articularly and 22� of tibial varus deformity (A). To correct both the varus and recurvatum deformities, an osteotomy wasperformed and a hexapod frame was used, acting as a virtual hinge, with gradual adjustments made to correct the deformity(B). She was in the frame for a total of 3 months, initially making the daily adjustments and then allowing for consolidation ofthe bony regenerate. She was staged to total knee arthroplasty 2.5 years after frame removal using primary components (C).


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Figure 5

Photographs and radiographs showing femoral varus deformity and LLD. A 51-year-old woman with a history of unknownmetabolic disease presented with knee pain, bilateral hip pain, and back pain progressing since childhood. She feltcomfortable with a 12.5-cm block under her left leg to compensate for her LLD (A). Preoperative planning showed amechanical axis deviation of 98 mm medial and an overall alignment with 35� of varus deformity along with a procurvatumdeformity of 26� (B). A retrograde intramedullary lengthening nail was used to correct the limb length, varus, andprocurvatum deformity. Lengthening was performed on the magnetic intramedullary lengthening nail at a rate ofapproximately 1 mm daily (C). She was staged to a TKA with a constrained polyethylene insert one year later with removal ofthe retrograde nail at the time of surgery (D). Postoperative clinical photograph and standing alignment radiograph showingcorrection of the deformity (E). LLD = limb-length discrepancy, TKA = total knee arthroplasty




include (1) primary TKA, (2) simulta-neous corrective osteotomy and TKA,and (3) staged correctiveosteotomyanddelayed TKA. In cases in which anosteotomy is deemed necessary, thedecisionmust bemade between either astaged or simultaneous osteotomybefore TKA. Regardless of whether theosteotomy is staged or simultaneous,the objective is to restore the mechani-cal alignment of the femur and tibia toaccommodate the arthroplasty implantand to do this using the least possibleradical bone resection, soft-tissue re-leases, and reduce the need for con-strained implants.There are pros and cons to both the

staged approach and the simulta-neous approach for correcting extra-articular deformity for TKA. A stagedosteotomy allows for greater surgicalflexibility for optimizing deformitycorrection because no concern existswith regard to interfering with imme-diate TKA. If necessary, plates andscrews can be used and later removedas needed. In addition, the oste-otomy is given the opportunity for fullhealing without the risk of cementintrusion from TKA. In addition,correction of underlying malalign-ment improves knee kinematics, andsymptoms may be alleviated, possiblydelaying the need for TKA. The au-thors find this to be more common inpreoperative mechanical valgus de-formities. Lonner et al31 reported 11knees with extra-articular deformity(10 fracture nonunions and onepatient with hypophosphatemic rick-ets) who underwent a simultaneousfemoral osteotomy followed by TKAin the same surgical setting. Althoughthey reported significant improvementsin the Knee Society Score (KSS) out-comes, the complication rate was 45%and included one osteotomy nonunion,two manipulations under anesthesiafor stiffness, one acute pulmonaryembolism, and one case of symptom-atic implant requiring removal.31

Although it is the authors’ prefer-ence to use a staged approach when

an osteotomy is deemed necessary,there are also benefits to a simulta-neous approach. If the surgeon isadept at both osteotomy and ar-throplasty and performs both simul-taneously, the patient only undergoesone surgical procedure and one re-covery period. However, the recoverymay be longer and more difficult thanthe two recoveries after a stagedapproach. Furthermore, in a simul-taneous approach, surgeons shouldbe cognizant of blood loss manage-ment and management of cementduring implantation of the total kneebecause cement may be prone toextrude through the osteotomy site.Comparing risks and benefits of

the staged versus simultaneous ap-proach, we generally prefer a stagedosteotomy followed by subsequentarthroplasty with potential removalof osteotomy implant as needed.

Surgical Technique andImplant Choice for Extra-articular OsteotomyCorrection

Multiple surgical techniques andmethods of fixation have been usedfor osteotomy correction includ-ing intramedullary nails, plate andscrew constructs, or hexapod exter-nal frames.32 Internal lengtheningintramedullary nails can be particu-larly useful if there is both an angulardeformity and an LLD. Distal fem-oral and proximal tibial plates can beused and are frequently removedbefore or at the time of the arthro-plasty procedure (Figure 6).External fixation devices such as

the hexapod frame can also be usedfor deformity correction with oste-otomy. Benefits of this fixationmethod for deformity correcting os-teotomies include gradual correc-tion and control in multiple planes.Gradual correction is beneficial forminimizing peroneal nerve injury,whichmay be seenwith acute angular

correction.33 Disadvantages of hexa-pod frames include patient discom-fort and risk of pin-site infection.Deep osteomyelitis has been reportedin up to 4% of patients undergoingexternal fixation, which is particu-larly concerning in patients requiringarthroplasty.34 In staged cases inwhich the osteotomy implant isremoved either shortly before or inthe same setting as the TKA, stem-med arthroplasty implants may beused to bypass the osteotomy siteand stress risers created after implantremoval.35

In patients with extra-articular de-forming in whom a subsequent TKAis expected, osteotomy should focuson correcting the femur and tibia totheir respective anatomic and me-chanical axes, rather than perfectingthe overall alignment of the entirelimb. If an acute correction is feasible,intramedullary nails are preferredbecause they may easily be removedat the time of TKA. Antegrade fem-oral nails are optimal because theycan be left in place, and computernavigation or patient-specific cuttingguides are used instead of an intra-medullary guide. In cases in whichgradual correction is needed, externalfixators are used. Surgeons must beaware of previous incisions and con-sider the future TKA incision whenperforming the deformity correction.A complete correction of axial planedeformity is also performed at thetime of osteotomy because TKA al-lows for minimal correction in theaxial plane.

Special Considerations inTotal Knee ArthroplastyAssociated With Extra-articular Deformity

Computer-assisted navigation pro-vides some valuable features whenmanaging an extra-articular defor-mity at the time of TKA, especially inthe setting of a previous implant.


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Figure 6

Algorithm demonstrating suggested management of severe osteoarthritis of the knee in the setting of extra-articulardeformity.




Benefits of computer-assisted, ro-botic, or patient-specific cuttingguides include avoiding the use of anintramedullary femoral alignmentrod and more reliable access to themechanical axis without the use offluoroscopy.36-39 Catani et al36

reported the use of an image-freenavigation system (Stryker Naviga-tion) in a series of 20 patients with anextra-articular deformity secondaryto remote femur or tibia fracture.Computer-assisted navigation wasused to identify the center of thefemoral head, and the proximal tibiacut was also aligned with themechanical axis of the tibia usingnavigation. The authors demon-strated an improvement from a meanpreoperative alignment of 10.4� 68.3� varus to a mean postoperativealignment of 0.8� 6 1.2� varus andan improvement in the KSS from48.4 to 91.4. In addition, theyreported no complications in thismore complex cohort.36 The use ofcomputer technologies for extra-articular deformity is a rapidlyevolving field, and additional studiesare needed to define their role in themanagement of extra-articulardeformity.In cases of complex extra-articular

deformity, the surgeon must also beaware of certain complications thatare more prone to arise and mustcounsel the patient appropriately.In a case series of 12 patients withextra-articular deformity secondaryto skeletal dysplasia who wereundergoing TKA, Kim et al33

reported that 3/12 required custom-ized implants, 5/12 required con-strained polyethylene inserts, and2/12 experienced transient peronealnerve palsies. In our experience, forcases of particularly severe multi-planar deformities, staged osteotomyand a gradual correction using ahexapod frame is a useful tool thatallows for accommodation of softtissues and neurovascular structuresto correction of the deformity.

Furthermore, infection is a concernin patients with retained implantwhoare undergoing TKA. Cross et al40

reported a 5% infection rate in asmall series of patients undergoingconversion from high tibial oste-otomy to TKA. Higher infectionrates have been reported with the useof hexapod frames,34,41 so whenusing these devices before TKA,surgeons should ensure that patientsare free of any evidence of deep orsuperficial infection before proceed-ing with arthroplasty with inflam-matory markers and joint aspirationif elevated.Ligamentous contractures and lax-

ity may be present in the knee in casesof extra-articular deformity.4 Sur-geons performing TKA in the settingof extra-articular deformity shouldbe prepared to perform ligamentousreleases and use constrained im-plants as needed.

Summary

Preoperative full-length standing hip-to-ankle radiographs are necessaryfor preoperative assessment of extra-articular deformity in the setting ofTKA.Measurements includingMAD,LDFA, MPTA, posterior proximaltibial angle, posterior distal femoralangle, JLOA, and CORA should bemade to distinguish between intra-articular and extra-articular defor-mity and to plan for the correction.Preoperative templating should beused to assess bony cuts that will beneeded for intra-articular correction.In cases of severe deformity in whichTKA alone is not possible, there arenumerous advantages to staging theosteotomy rather than performing asimultaneous osteotomy correctionand then arthroplasty in the samesurgical setting. It is important toconsider that ligamentous laxity isassociated with extra-articular defor-mity, andconstrained implants shouldbe available and used appropriately.

Special care should be taken to protectneurovascular structures, especiallythe peroneal nerve, in cases in which alarge deformity correction is per-formed, and patients should be edu-cated preoperatively of this increasedrisk. A thorough preoperative neu-rovascular examination and appro-priate studies to document the statusof the neurovascular structures maybe indicated. Hexapod frames maybe used for gradual correction toprotect neurovascular structures. Inaddition, an increasing role exists forcomputer navigation both for man-aging femoral malunions at the timeof TKA and for performing TKAafter deformity correction.

References

References printed in bold type arethose published within the past 5years.

1. Kurtz S, Ong K, Lau E, Mowat F, HalpernM: Projections of primary and revision hipand knee arthroplasty in the United Statesfrom 2005 to 2030. J Bone Joint Surg Am2007;89:780-785.

2. Sharma L, Song J, Felson DT, Cahue S,Shamiyeh E, Dunlop DD: The role of kneealignment in disease progression andfunctional decline in knee osteoarthritis.JAMA 2001;286:188-195.

3. Thiele K, Perka C, Matziolis G, Mayr HO,Sostheim M, Hube R: Current failuremechanisms after knee arthroplasty havechanged: Polyethylene wear is less commonin revision surgery. J Bone Joint Surgery-American 2015;97:715-720.

4. Wolff AM, Hungerford DS, Pepe CL:The effect of extraarticular varus andvalgus deformity on total knee arthroplasty.Clin Orthop Relat Res 1991;271:35-51.

5. Naqvi A, Mistry JB, Elmallah RK,Chughtai M, Mont MA: Management ofextra-articular deformities in kneearthroplasty, in Mont MA, Tanzer M, eds:Orthopaedic Knowledge Update 5: Hipand Knee Reconstruction, ed 5. Rosemont,IL, AAOS, 2017, pp 210-219.

6. Weinberg DS, Park PJ, Liu RW: Associationbetween tibial malunion deformityparameters and degenerative hip and kneedisease. J Orthop Trauma 2016;30:510-515.

7. Kettelkamp DB, Hillberry BM, MurrishDE, Heck DA: Degenerative arthritis of the


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knee secondary to fracture malunion. ClinOrthop Relat Res 1988;234:159-169.

8. Phillips JRA, Trezies AJH, Davis TRC:Long-term follow-up of femoral shaftfracture: Relevance of malunion andmalalignment for the development of kneearthritis. Injury 2011;42:156-161.

9. Alghamdi A, Rahmé M, Lavigne M, MasséV, Vendittoli P-A: Tibia valga morphologyin osteoarthritic knees: Importance ofpreoperative full limb radiographs in totalknee arthroplasty. J Arthroplasty 2014;29:1671-1676.

10. Khakharia S, Bigman D, Fragomen AT,Pavlov H, Rozbruch SR: Comparison ofPACS and hard-copy 51-inch radiographsfor measuring leg length and deformity.Clin Orthop Relat Res 2011;469:244-250.

11. Paley D: Principles of DeformityCorrection, New York, NY, Springer BerlinHeidelberg, 2002.

12. PomerantzML, Glaser D, Doan J, Kumar S,Edmonds EW: Three-dimensional biplanarradiography as a new means of accessingfemoral version: A comparitive study ofEOS three-dimensional radiography versuscomputed tomography. Skeletal Radiol2015;44:255-260.

13. Sabharwal S, Kumar A: Methods forassessing leg length discrepancy. ClinOrthop Relat Res 2008;466:2910-2922.

14. Sabharwal S, Zhao C, McKeon JJ,McClemens E, Edgar M, Behrens F:Computed radiographic measurement oflimb-length discrepancy. Full-lengthstanding anteroposterior radiographcompared with scanogram. J Bone JointSurg Am 2006;88:2243-2251.

15. Tanzer M, Makhdom AM: Preoperativeplanning in primary total knee arthroplasty.J Am Acad Orthop Surg 2016;24:220-230.

16. Wang JW, Wang CJ: Total kneearthroplasty for arthritis of the knee withextra-articular deformity. J Bone Joint SurgAm 2002;84-A:1769-1774.

17. Koenig JH, Maheshwari AV, Ranawat AS,Ranawat CS: Extra-articular deformity isalways correctable intra-articularly: In theaffirmative. Orthopedics 2009;32. doi: 10.3928/01477447-20090728-22.

18. Papagelopoulos PJ, Karachalios T,Themistocleous GS, Papadopoulos EC,Savvidou OD, Rand JA: Total kneearthroplasty in patients with pre-existingfracture deformity. Orthopedics 2007;30:373-378.

19. Xiao-Gang Z, Shahzad K, Li C: One-stagetotal knee arthroplasty for patients withosteoarthritis of the knee and extra-articular deformity. Int Orthop 2012;36:2457-2463.

20. Hungerford DS: Extra-articular deformityis always correctable intra-articularly: Tothe contrary. Orthopedics 2009;32:677-679.

21. Wang J-W, Chen W-S, Lin P-C, Hsu C-S,Wang C-J: Total knee replacement withintra-articular resection of bone aftermalunion of a femoral fracture: Can sagittalangulation be corrected? J Bone Joint SurgBr 2010;92:1392-1396.

22. Rozbruch SR, Segal K, Ilizarov S, FragomenAT, Ilizarov G: Does the taylor spatialframe accurately correct tibial deformities?Clin Orthop Relat Res 2010;468:1352-1361.

23. Rozbruch SR, Fragomen AT, Ilizarov S:Correction of tibial deformity with use ofthe Ilizarov-Taylor spatial frame. J BoneJoint Surg Am 2006;88(suppl 4):156-174.

24. Radler C, Kranzl A, Manner HM,Höglinger M, Ganger R, Grill F: Torsionalprofile versus gait analysis: Consistencybetween the anatomic torsion and theresulting gait pattern in patients withrotational malalignment of the lowerextremity. Gait Posture 2010;32:405-410.

25. Rozbruch SR: Adult posttraumaticreconstruction using a magnetic internallengthening nail. J Orthop Trauma 2017;31(suppl 2):S14-S19.

26. Fragomen AT, Rozbruch SR: Lengtheningand deformity correction about the kneeusing a magnetic internal lengthening nail.SICOT-J 2017;3:25.

27. Fragomen AT, Rozbruch SR: Retrogrademagnetic internal lengthening nail for acutefemoral deformity correction and limblengthening. Expert RevMedDevices 2017;14:811-820.

28. Kirane YM, Fragomen AT, Rozbruch SR:Precision of the PRECICE internal bonelengthening nail. Clin Orthop Relat Res2014;472:3869-3878.

29. Muthusamy S, Rozbruch SR, FragomenAT: The use of blocking screws withinternal lengthening nail and reverse rule ofthumb for blocking screws in limblengthening and deformity correctionsurgery. Strateg Trauma Limb Reconstr2016;11:199-205.

30. Kim SH, Rhee S-M, Lim J-W, Lee H-J: Theeffect of leg length discrepancy on clinicaloutcome after TKA and identification ofpossible risk factors. Knee Surg SportsTraumatol Arthrosc 2016;24:2678-2685.

31. Lonner JH, Siliski JM, Lotke PA:Simultaneous femoral osteotomy and totalknee arthroplasty for treatment ofosteoarthritis associated with severe extra-articular deformity. J Bone Joint Surg Am2000;82:342-348.

32. Seah KTM, Shafi R, Fragomen AT,Rozbruch SR: Distal femoral osteotomy: Isinternal fixation better than external? ClinOrthop Relat Res 2011;469:2003-2011.

33. Kim RH, Scuderi GR, Dennis DA, NakanoSW: Technical challenges of total kneearthroplasty in skeletal dysplasia. ClinOrthop Relat Res 2011;469:69-75.

34. Kazmers NH, Fragomen AT, Rozbruch SR:Prevention of pin site infection in externalfixation: A review of the literature. StrategTrauma Limb Reconstr 2016;11:75-85.

35. Weiss NG, Parvizi J, Hanssen AD,Trousdale RT, Lewallen DG: Total kneearthroplasty in post-traumatic arthrosis ofthe knee. J Arthroplasty 2003;18(3 suppl1):23-26.

36. Catani F, Digennaro V, Ensini A, LeardiniA, Giannini S: Navigation-assisted totalknee arthroplasty in knees withosteoarthritis due to extra-articulardeformity. Knee Surg Sports TraumatolArthrosc 2012;20:546-551.

37. Hazratwala K, Matthews B, Wilkinson M,Barroso-Rosa S: Total knee arthroplasty inpatients with extra-articular deformity.Arthroplast Today 2016;2:26-36.

38. Rhee SJ, Seo CH, Suh JT: Navigation-assisted total knee arthroplasty for patientswith extra-articular deformity. Knee SurgRelat Res 2013;25:194-201.

39. Kendoff DO, Fragomen AT, Pearle AD,Citak M, Rozbruch SR: Computernavigation and fixator-assisted femoralosteotomy for correction of malunion afterperiprosthetic femur fracture. JArthroplasty 2010;25:333.e13-333.e19.

40. Cross MB, Yi PY, Moric M, Sporer SM,Berger RA, Della Valle CJ: Revising anHTO or UKA to TKA: Is it more like aprimary TKA or a revision TKA? JArthroplasty 2014;29(9 suppl):229-231.

41. Davies R, Holt N, Nayagam S: The care ofpin sites with external fixation. J Bone JointSurg Br 2005;87:716-719.




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