metatarsat osteotomy for the correction of metatarsus adductus

METATARSAT OSTEOTOMY FOR THE CORRECTION OFMETATARSUS ADDUCTUSD. Richard DiNapoli, D.P.M.Stephen V. Corey, D.P.M.INTRODUCTIONAny discussion of metatarsal osteotomies for the correctionof metatarsus adductus must address a numberof points. What follows is an attempt to focus on severalof these including basic philosophy in clinical examination,radiographic evaluation, and treatment techniquesemployed.Treatment PhilosophyThe diagnosis of metatarsus adductus has been fullyreviewed elsewhere. For the sake of our discussion wewill define metatarsus adductus as a transverse planedeformity at the level of the tarsometatarsal joint. Furtherdefinition and classification of the deformity will bediscussed in terms of our surgical approach.The pediatric/adolescent patient with the deformitymetatarsus adductus, represents an entirely different setof circumstances from a surgical standpoint than doesthe adult patient. ln dealing with a pediatric deformitythere exists many more surgical variables. An individualwith metatarsus adductus as a primary deformity willhave greater expectations from treatment than will thepatient that presents with residual metatarsus adductusfrom a previously treated club foot. Both the presenceof open epiphyses and extrinsic forces that exist cansignificantly alter the structure of the foot over time.Finally, of great importance to the treatment is theparents' expectations and depending on the age of thepatient, the patient's expectations.Timing of surgical procedures is of great importancein treating this deformity. The physician must developa time frame for this overall treatment. Younger patientsshould receive a course of casting prior to any surgicalrepair.As with most pediatric deformities the patient does notexperience the same symptoms that are characteristic ofadult deformities. lf the pediatric patient is experiencingpain the seriousness of the condition is signaled.Generally, in the metatarsus adductus patient, the parentwill describe the symptoms as a set of clinically relatedconditions. These may include excessive and abnormalshoe wear, marked in-toe walking, constant tripping, andinability to maintain the same activity level as childrenthe same age.Considerations for surgery include the age of thepatient, symptomatology, severity of deformity, degreeof compensation, and the degree of control which maybe present.Indications for surgery will be twofold: in the asymptomaticpatient there should be severe structural deformitywith u ncontrolled compensation or rapid progressionof deformity. In the symptomatic patient whether it iscompensated or uncompensated, controllable or uncontrollablesurgery is advisable.Contraindications to surgery are the asymptomaticdeformity with only mild structural deformity that is controllableand with only minimal progression whether itbe uncompensated or compensated.CTINICAL EVATUATIONA thorough clinical evaluation includes:lnspection of the entire lower extremityfor gross orthopedic deformities and thepresence of any existing deformities proximallyDetermination of the primary plane of thedeformityBiomechanical examinationGait examination.It is helpful for the patient to be in shorts for theexamination to allow the physician to inspect the entireIower extremity. The thigh should reveal developmentconsistent with age. The presence of genu valgum orgenu varum may contribute to the deformity and shouldbe noted. Further inspection of the leg should be madeto determine the existence of tibial torsion or tibialvarum.Generally speaking metatarsus adductus exists as apurely transverse plane deformity at the level of the242

tarsometatarsal joint, as evidenced by the disparity in themedial and lateral foot borders (Fig. 1). The presentationof a convex lateral border and a concave medial borderwill be evident but depends on the degree of compensation.ln the uncompensated foot the convexity of theIateral border will be most marked with the styloid processof the fifth metatarsal very prominent. The medialarch may exhibit more height than expected for a childin his/her particular age group. ln contrast the totallycompensated deformity may reveal only a mild amountof convexity to the lateral border, a rather low or evenflattened medial arch and even some abduction of thedigits. Many authors have observed the separation of thehallux and the second digit and have suggested that thisseems more prevalent in the uncompensated and partiallycompensated foot types.During a thorough biomechanical evaluation, determinationof the presence of sagittal and frontal planeabnormalities must be made. This will affect the surgicalstrategy. The presence of a gastrocnemius orgastrocnemius-soleus equinus must be addressed toinsure the success of a metatarsus adductus repair.Evaluation of subtalar joint motion is also of greatimportance. Finally, the presence of an uncompensatedrearfoot varus if present must also be addressed.The forefoot should be examined in the standardfashion, the subtalar joint should be in its neutral position,the midtarsal joint should be locked. This willpermit an accurate appraisal of the metatarsal alignmentin all three planes. If a true transverse plane deformityexists, the metatarsal heads will all be aligned on thesame transverse plane. Any difference in elevation betweenmetatarsals can be compensated at the time ofsurgery. Careful preoperative planning will help to ensurea successful outcome. A gross frontal plane deformitymay exist in the form of a rigid forefoot varus. Actualdetermination of inversion of the metatarsals is notclinically possible.A common radiographic finding that is difficult toquantify clinically is the degree of adduction of eachmetatarsal. There may be an actual increase in the degreeof adduction of each metatarsal from lateral to medialwith the greatest amount being present in the firstmetatarsal. This can be considered as the domino effect.Another parameter to consider is the degree of flexibilitypresent in the deformity. A rigid metatarsus adductusdeformity will require more aggressive treatmentthan a flexible deformity. Postoperative casting andsplinting will be of assistance in reducing the adductusin the flexible deformity.Fig. 't. Clinical representation of resistant metatarsus adductus.Consideration of the presence of functional halluxlimitus must be made. Functional hallux Iimitus is theinability of the great toe to extend over the first metatarsalwhen the heel is lifting off the ground. This createsa sagittal plane motion blockade at the first metatarsophalangealjoint which must be compensated for atthe level of the midtarsal joint or ankle joint. The endresult is an accentuation of the deformity through anadductory twist at heeloff. This can be corrected at thetime of surgery by plantarflexing the first metatarsal andincreasing the declination and stability of the first ray.RADIOGRAPHIC EVATUATIONSThe diagnosis of metatarsus adductus is generallymade by clinical evaluation. Radiographic studies do contributeto determining the extent of the deformity as wellas providing greater insight to the osseous relationships.Full weight-bearing dorsoplantar and lateral views areperformed and used not only for determination ofangular relationships but to evaluate the osseous maturityof the foot (Fig. 2).The dorsoplantar view is of primary importance fordetermination of the metatarsus adductus angle. Thereare two methods currently used. The first depends ondefining the longitudinal axis of the lesser tarsus. Thisis accomplished by plotting a series of points beginningwith the medial most aspect of the first metatarsalcuneiform joint followed by the medial most aspect ofthe talonavicular joint, the lateral most aspect of the fifthmetatarsal cuboid joint, lastly the lateral most aspect ofthe calcaneocuboid joint. Two lines are then drawn, oneconnecting the medial points and one connecting thelateral points. Each of these lines is then bisected anda third line is drawn connecting the bisect points acrossthe midfoot. A fourth line is then constructed perpen-243

Fig. 2. Preoperative radiographs, A & B, of symptomatic metatarsusadductus.dicular to the third Iine and represents the longitudinalaxis of the midfoot.The bisection of the second metatarsal will serve as thelongitudinal axis of the metatarsals. The angular relationshipbetween the longitudinal axis of the lesser tarsusand the longitudinal axis of the second metatarsal willrepresent the metatarsus adductus angle (Fig. 3).A second method of defining the metatarsus adductusangle has been proposed. In this method the longitudinalaxis of the metatarsals remains the longitudinal bisectorof the second metatarsal. The angle is def ined utilizingthe longitudinal bisector of the second cuneiform(Fig. a). The authors found that their method resulted inan increase of three degrees over an accepted normalmeasurement of twenty-one degrees.There is much controversy over a strict definition ofmetatarsus adductus. Some authors define pathologicalmetatarsus adductus as being greater than twenty-onedegrees. Others have liberally defined normal as ten totwenty degrees. The faculty and staff at the Podiatrylnstitute use the following guidelines for definingmetatarsus adductus.Classification of Metatarsus AdductusNormalMitdModerateSevere< 15 degrees16-25 degrees26-35 degrees> 35 degreesThese numbers are guidelines and are to be used inquantifying the deformity. Keep in mind the irnportanceo{ angle and base of gait radiographs. The patient mustbe positioned carefully because supination of the subtalarjoint can result in an apparent increase in theamount of metatarsus adductus.As the child matures the appearance of the bases ofthe metatarsals will also change. Recall that the epiphysisof the first metatarsal is at its base and f inal ossificationdoes not take place until 16 to 20 years of age and canvary substantially. The epiphyses of the lesser metatarsalsare at the neck. They close at approximately the sameage. In early childhood the bases are rather round inappearance. As the child reaches adolescence the baseand neck will square themselves off and resemble adultmetatarsals. The majority of procedures will be performedat the proximal one-third to one-fourth of themetatarsal.OSSEOUS SURGERYMetatarsal osteotomy has been advocated for the correctionof metatarsus adductus alone or in combinationwith other procedures. Berman and Gartland introducedosteotomies of all five metatarsals for the correction ofmetatarsus adductus in 1971. Since that time the procedurehas undergone several refinements. lt serves asthe foundation for the correction of resistant metatarsusadductus in children age six to eight or older.The original Berman and Cartland procedure useddome-shaped osteotomies of the base of the metatarsals.ln severe cases the removal of laterally based wedges ofbone from the metatarsal base facilitated the correction.Initially the metatarsal osteotomies were not fixated, buteventually unthreaded Steinmann pins were used for fixationof the first and fifth metatarsals.244

AFig. 3. Diagrammatic representation of determination of metatarsusadductus angle by Whitney. A. Plotting of critical points and determinationof longitudinal bisector of lesser tarsus. B. Lesser tarsus axis isrepresented by the bisection of the longitudinal bisector of the lessertarsus. C. Diagrammatic representation of the metatarsus adductusangle (see text for complete details).ln the following section the various modifications ofthe Berman and Cartland procedure will be examined,the different types of fixation will be discussed as wellas the complications and postoperative management.The soft tissue dissection has been discussed elsewhereand will not be addressed.Over the past fifteen years the staff of the PodiatryInstitute has used a combination of procedures for thecorrection of metatarsus adductus in the child age sixand older with moderate to severe metatarsus adductusunresponsive to conservative therapy. ln addition theseprocedures are used for the correction of symptomaticresidual metatarsus adductus in the patient withpreviously corrected talipes equinovarus.Modified Berman-Gartland Procedu reFig. 4. Alternative method of determining metatarsus adductus angleaccording to Engel.The modified Berman-Cartland procedure uses eithertransverse base wedge osteotomies or oblique basewedge osteotomies of the metatarsals with internal fixationof stainless steel wire, Kirschner wire (K-wire), smallbone staples or small bone screws (Fig. 5).245

Fig.5. Preoperative and postoperative radiographs of metatarsus adductusrepair using modified Berman and Cartland procedure.The Modif ied Berman-Cartland usually employs threedorsal longitudinal skin incisions and the principles ofanatomic dissection. The periosteum of each metatarsalmust be preserved with great care when exposing theproximal metaphyseal region. Nowhere is this moreimportant than in exposing the base of the f irst metatarsal.ldentification of the epiphyseal growth plate is criticalto avoid damaging it during the osteotomy, and oneshould avoid excessive reflection of the periosteum surroundingthe growth plate (Fig. 6).Prior to performing the osteotomies the surgeon mustdecide upon the sequence of execution of multiplemetatarsal procedures. This will vary with the preferenceand experience of the surgeon. Common patterns forperforming the osteotomies are 5-1-2-3-4 and 1-2-3-4-5. Insevere deformities, it may be difficult to reduce theadduction of the first metatarsal after osteotomy withoutfirst completing osteotomies on the adjacent metatarsals.ln some cases it may not be necessary to to perform anosteotomy on the fifth metatarsal to achieve correction.The staff at the Podiatry Institute has further modifiedthe technique of Berman and Cartland to use closingabductory base wedge osteotomies of the first and fifthmetatarsal as opposed to transverse base wedgeosteotomies. The oblique base wedge osteotomiesfacilitate the use of AO/ASIF internal fixation techniqueswith small cortical or cancellous screws.The fifth metatarsal is identified through the lateralincision, the periosteum is incised in a linear mannerover the base and proximal portion of the shaft. TheFig. 6. Clinical photo of epiphysis of first metatarsal. Note identificationof first metatarsal cuneiform articulation.insertion of the peroneus brevis tendon should not bedisturbed. lf a peroneus tertius is present then theperiosteal incision should be placed laterally. An obliqueosteotomy is performed from distal-lateral to proximalmedialpreserving a medial cortical hinge. The osteotomyis placed such that it is oriented approximately sixtydegrees to the long axis of the metatarsal and Iies in thesagittal plane. To insure that the osteotomy is in the sagittalplane the medial cortical hinge should be perpen-246

dicular to the weightbearing surface or the plantar surfaceof the foot.lf sagittal plane correction is also desired (dorsiflexionor plantarflexion) then the cortical hinge is appropriatelyangled to the transverse plane. A second convergingosteotomy is then performed and an appropriate wedgeof bone removed (Fig. 7). The exact size of the wedgeis determined by the extent of the deformity. The corticalhinge is weakened, the osteotomy is reduced andstabilized temporarily.The first metatarsal is identified through the medialincision, following deep fascial dissection, the firstmetatarsal cuneiform articulation is located. This willassist in identifying the epiphyseal growth plate. Theperiosteum is incised in an oblique fashion fromproximal-medial to distal-lateral along the course of theproposed osteotomy. The epiphyseal growth plate isidentified, and minimal stripping of the periosteum isperformed at this level. The osteotomy is then performedin an oblique fashion from distal-lateral to proximalmedial,preserving a medialcortical hinge in the sagittalplane. The osteotomy should be approximately 45degrees to the long axis of the first metatarsal (Fig. B).A second converging osteotomy is performed and anappropriate wedge section of bone removed, the hingeis weakened and the osteotomy is reduced and temporarilystabilized.Cenerally, osteotomies are performed on the centralthree metatarsals in a similar fashion. The decision to performtransverse or oblique base wedge osteotomies isa matter of surgeon's preference. An influencing factorin that decision is the type of fixation to be used. lf thesurgeon elects to use stainless steel wire in a verticalmattress fashion or a horizontal mattress fashion theoblique base wedge osteotomy will facilitate its use. Thetransverse base wedge is easily fixated with K-wires. Fixationtechniques will be discussed in more detail later.Both transverse and oblique base wedge osteotomiesare performed in the proximal metaphysis and requirean intact medial cortical hinge that lies primarily in thesagittal plane. Proper orientation of the osteotomy iscritical to maintaining the metatarsal head level in boththe sagittal and transverse planes. This also requiresaccurate wedge resections of bone from each affectedmetatarsal. The severity of the deformity will dictate theamount of bone that is removed. Usually a greateramount of bone removal is required from the medialmetatarsals (one and two) than from the lateral threemetatarsals. Maintenance of the medial cortical hingebecomes increasingly more difficult as the size of thewedge resection increases. lntraoperative radiographsare helpful to insure adequate wedge resection and correctivealignment of the metatarsals.Fig. 7. Oblique base wedge osteotomy of fifth metatarsal.Fig. 8. Oblique base wedge osteotomy of first metatarsal.Lepird ProcedureRichard Lepird (1981) introduced a new osseous procedurefor the correction of metatarsus adductus in thechild age six to eight years of age. Since its introductionit has been used extensively by the faculty of the PodiatryInstitute. The procedure uses rotational osteotomies ofthe central three metatarsals as opposed to wedge resections(Fig. 9).The procedure is performed through a standard dorsalthree incisional approach similar to that used for theModified Berman-Cartland procedure. The sequence ofexecution of the osteotomies will vary with the surgeon.The osteotomies of the first and fifth metatarsals are247

Fig. 9. Diagrammatic representation of the Lepird procedure for correctionof resistant metatarsus adductus (see text for details).oblique base wedge osteotomies as described previously.The central three osteotomies are rotational ortranspositional through and through cuts that do not requirebone resection. The osteotomy is initiated dorsallyat the junction of the proximal and middle one thirdsof the metatarsal. It is an oblique osteotomy orientedfrom dorsal-distal to plantar-proximal essentially parallelto the plantar aspect of the foot (approximately 45degrees to the dorsal surface of the metatarsal). Greatcare should be taken to insure that the osteotomy exitsproximal to the metatarsal cuneiform joint. When theosteotomy is performed a small portion of the cortex ispreserved to prevent motion between the proximal anddistal segments prior to fixation. The saw blade mustparallel the plantar aspect of the foot to produce anosteotomy that results in pure transverse plane motionwhen the distal segment is abducted on the proximalportion (Fig. 10). lf the saw blade is angled medially theresulting osteotomy would produce dorsiflexion as wellas abduction to the distal segment. Similarly, if the sawblade were angled laterally the resulting osteotomywould produce simultaneous plantarflexion and abduction.These type results may be warranted dependingupon the deformity.The Lepird procedure was developed to take advantageof the AO/ASIF concept of internal compression fixation.Fig. 10. Rotational osteotomy of lesser metatarsals. Saw blade is essentiallyparallel to plantar aspect of foot.Prior to complete transection of the metatarsal, fixationis performed using small cortical bone screws orientedperpendicular to the plane of the osteotomy. Temporaryfixation in the form of bone reduction forceps or K-wiresis not necessary because a small portion of the cortexhad been maintained. When the osteotomy is completed,the screw is placed across the osteotomy. Before thescrew is finally secured, the distal shaft portion of themetatarsal is rotated laterally into the desired position(Fig. 11). Radiographs are employed to evaluate theamount of correction. lf more or less correction isdesired, the screw can be loosened, the appropriate positionobtained and the screw secured (Fig. 12).COMPTICATIONS AND IIXATIONCritical to the use of transverse or oblique base wedgeosteotomies is the preservation of a medial cortical248

hinge. lf the cortical hinge f ractures significant instabilitycan result. lt is imperative that adequate stabilization ofthe segments be accomplished. Significant instability canincrease the likelihood of displacement, malalignment,delayed union/ nonunion, pseudo-arthrosis, or osseousbridging. Fixation for transverse base wedge osteotomiescan be accomplished with the following techniques:K-wires used in a percutaneous or buried fashion,fixating individual metatarsals or a single K-wire tostabilize all the metatarsals. Stainless steel wire can beemployed in several ways; in a cerclage fashion, horizontalor vertical mattress, or in combination with K-wiressimilar to a tension band. Small bone staples may alsobe employed.Fig. 11. Fixation of rotational osteotomy using AO technique. Distalmetatarsal segment is rotated into desired position.A f ull discussion of the complications of the obliquebase wedge osteotomy and fixation techniques is beyondthe scope of this paper. The faculty of the PodiatryInstitute has employed screw fixation for oblique basewedge osteotomies for more than ten years with greatsuccess. Essential to the use of AO/ASIF techniques off ixation of the first or f ifth metatarsal is the preservationof a medial cortical hinge. Strict adherence to the AOprinciples decreases the incidence of failure. As previouslymentioned, in the presence of an open epiphysisin the first metatarsal, the osteotomy is performed acentimeter more distally. This technique has been usedboth in correction for metatarsus adductus and injuvenile hallux abductovalgus without reportedincidence of injury to the physis or shortening of the firstmetatarsal.The rotational osteotomy used in the Lepird techniqueoffers a number of advantages over traditional basewedge osteotomies. lt precludes the need for an intactmedial cortical hinge. Secondly, the use of small corticalor cancellous bone screws provides rigid internal com-Fig. 12. Postoperative radiographs of Lepird procedure'249

pression fixation resulting in primary bone healinggreatly and reducing the likelihood of osseous bridgingbetween adjacent metatarsals. Finally, obtaining desiredcorrection is made easier during surgery simply byloosening the screws and repositioning the metatarsalsegments and resecuring the screws.The technique of rotational osteotomies is not withoutits disadvantages. lf the osteotomy is performed too verticalthe screw fixation proves inadequate or may fail,then stabilization of the metatarsal segments will be difficultdue to the through and through nature of theosteotomy. In such a situation fixation would best beaccomplished with a combination of stainless steel wireand K-wire. lf the screw fixation fails during thepostoperative period, the screw may function as a distractingforce resulting in a delayed union, nonunion,malalignment, or pseudarthrosis. The use of internal fixationmay mean removal of hardware in the future anda second surgical procedure.POSTOPERATIVE MANAGEMENTlmmediately postoperative the patient is placed in abelow-knee compression cast for three to five days. Thisis followed by a below-knee non weight-bearing cast forsix to eight weeks. Radiographs are performedperiodically to access the healing process. In selectedcases, the patients may have the cast bivalved permittingearly active range of motion exercise and fasterreturn to normal function.ReferencesBerman A, Gartland JJ: Metatarsal osteotomy for thecorrection of adduction of the fore part of the foot inchildren. J Bone Joint Surg 534:498-506, 1971.Brown JH, Purvis CG, Kaplan EG, Mann l: Berman-Gartland operation lor correction of resistantadduction of the forepart of the foot. / Am PodiatryAssoc 67:841-847, 1977.Dananberg HJ: Functional hallux limitus and its relationshipto gait efficiency. J Am Podiatric Med Assoc76:648-652, 1986.Engel E, Erlich N, Krems I: A simplified metatarsaladductus angle. J Am Podiatry Assoc 73:620-628,1983.Canley JV: Lower extremity exam of the infant. J AmPodiatry Assoc 71:92, 1981.Marcinko DE,lannuzzi PJ, Thurber NB: Resistant metatarsusaciductus deformity (illustrated surgicalreconstructive techniques). J Foot Surg 25:86-94,1986.Root M, Orien W, Weed J, Hughes R: BiomechanicalExam of the Foot. Los Angeles, Clinical BiomechanicsCorp.1971, p 33.Ruch JA, Banks AS: Proximal osteotomies of the firstmetatarsal in the correction of hallux abducto valgus.In McClamry ED (ed): Comprehensive Textbook ofSurgery, vol 1. Williams and Wilkins, Baltimore, 1982,pp 195-211.Ruch JA, Merrill T: Principles of rigid internal compressionfixation and its application in podiatric surgery.ln McClamry ED (ed): Fundamentals of Foot Surgery.Williams & Wilkins, Baltimore, 1987, pp 246-293.Whitney AK: Radiographic Charting Technique.Pennsylvania College of Podiatric Medicine,Philadelphia, 1978, p 98.Yu CV, DiNapoli DR: Surgical correction of halluxvarus and metatarsus adductus. In McClamry ED (ed):Reconstructive Surgery of the Foot and Leg -Update BT.Tucker, GA, Podiatry Institute PublishingCompany, 1987.Yu GV, Johng B, Freirech R: Surgical management ofmetatarsus adductus deformity. Clinics in PodiatricMedicine and Su rgery 4:207-232, 1987.Yu CV, Wallace CF: Metatarsus adductus. ln McclamryED (ed): Comprehensive Textbook of Foot Surgery,vol1. Williams & Wilkins, Baltimore,1987, pp 324353.250