Lapidus Bunionectomy: Early Evaluation ofCrossed Lag Screws versus Locking Platewith Plantar Lag Screw

Amol Saxena, DPM, FACFAS,1 Aidan Nguyen, DPM,2 and Elise Nelsen, DPM2

We compared outcomes of the Lapidus bunionectomy fixated with crossed lag screws versus a lockingplate with a plantar lag screw. Forty patients who underwent Lapidus bunionectomy between August2001 and May 2006 were evaluated in a combined retrospective and prospective fashion. Crossed lagscrews were used in 19 of the patients, and a locking plate with a plantar lag screw was used in 21 ofthe patients. Other than fixation, the only interventional difference pertained to postoperative weightbearing, where those receiving the plate initiated full weight bearing on the operated foot at 4 weekspostoperative, as compared to 6 weeks for those receiving crossed screws. Overall, the mean preop-erative AOFAS hallux score was 41.75 � 2.52, and the postoperative score was 90.48 � 8.41 (P � .0001).The overall mean preoperative first intermetatarsal angle was 15.3° � 2.32°, and long term the angle was5.03° � 2.86° (P � .0001). When comparisons were made based on the method of fixation, use of anadjunct Akin osteotomy and surgery performed before 2003 were statistically significantly associatedwith crossed screw fixation, and the preoperative AOFAS score was statistically significantly higher in thelocking plate fixation group. There were no statistically significant differences related to postoperativecomplications between the 2 fixation groups. In conclusion, the Lapidus bunionectomy fixated with alocking plate and a plantar lag screw allows earlier weight bearing in comparison with crossed lag screws,without a difference in complications. Level of Clinical Evidence: 2 (The Journal of Foot & Ankle Surgery48(2):170–179, 2009)

Key Words: arthrodesis, complication, first metatarsal, hallux abductovalgus, interfragmental compres-

sion, nonunion, weight bearing

Many surgical procedures have been described to reducethe first intermetatarsal angle (IMA) in order to correctmoderate to severe hallux abductovalgus deformity. Theseprocedures include osteotomies of the first metatarsal per-formed at the head, neck, shaft, and/or base region, as wellas fusion of the first metatarsophalangeal joint (MTPJ) orthe first metatarsocuneiform joint (MCJ), the latter of whichis generally referred to as a Lapidus procedure (1–14). TheLapidus procedure has been used for the treatment of pa-tients with severe and recurrent bunion deformity with orwithout arthrosis of the first MCJ, a long first metatarsal,and hypermobility of the first metatarsal (1–3, 5–12). In thisstudy we retrospectively and prospectively obtained data in

Address correspondence to Amol Saxena, DPM, FACFAS, Departmentof Sports Medicine, Palo Alto Medical Foundation, 795 El Camino Real,Palo Alto, CA 94301. E-mail: HeySax@aol.com

1Podiatrist, Department of Sports Medicine, Fellowship Director, PaloAlto Medical Foundation, Palo Alto, CA.

2Fellow, Palo Alto Medical Foundation, Palo Alto, CA.Financial Disclosure: Wright Medical Technology, Inc., Arlington,

TN, funded a portion of this study.Conflict of Interest: None reported.Copyright © 2009 by the American College of Foot and Ankle Surgeons

1067-2516/09/4802-0013$36.00/0doi:10.1053/j.jfas.2008.12.009

170 THE JOURNAL OF FOOT & ANKLE SURGERY

order to compare 2 types of fixation for the Lapidus proce-dure, namely crossed interfragmental lag screws versus alocking plate with a single plantar lag screw.

Patients and Methods

After obtaining approval from our institutional reviewboard, we reviewed the records of consecutive patients whounderwent Lapidus arthrodesis using 2 crossing interfrag-mental lag screws, who were treated between August 2001and January of 2004; and 1 patient who underwent thisprocedure in June of 2005 was prospectively followed. Wealso prospectively collected data related to consecutive pa-tients who underwent Lapidus arthrodesis using a lockingplate with a single plantar lag screw, who were treatedbetween April 2004 and May 2006. To be included in theinvestigation, the patient had to have undergone, or bescheduled to undergo, a Lapidus arthrodesis. Our indica-tions for this procedure included moderate to severe halluxabductovalgus deformity that did not respond satisfactorilyto nonsurgical treatment, pain localized to the first metatar-sophalangeal joint (MTPJ), inability to wear regular shoe

gear without pain, an intermetatarsal angle (IMA) of 15° or

more on the weight-bearing anteroposterior (AP) radio-graph, sagittal displacement of the first metatarsal dorsallyon the weight-bearing lateral radiograph (as depicted byplantar gapping on the lateral radiograph or elevation rela-tive to the lesser metatarsals) (15) (Figure 1), previous bun-ionectomy with recurrent deformity and/or arthrosis of the firstMCJ, an elongated first metatarsal as determined by the radio-graphic assessment of the weight-bearing level of the firstmetatarsal, and patients with ligamentous laxity as deter-mined by the Wynn-Davies index (16). Specifically, for anypatient who displayed laxity in 3 of 5 pairs of joints, namelyhyperextension at the elbow, touching the volar surface ofthe forearm with the thumb, hyperextending the fingers suchthat they lie parallel to the forearm, hyperextension at theknee, and/or ankle dorsiflexion of more than 45°, it wastaken as positive that the patient had ligamentous laxity.

A number of outcomes of interest were measured, includ-ing patient age, sex, side operated on, whether or not a priorbunionectomy had been performed on the same foot,whether or not an adjunct Akin phalangeal osteotomy wasperformed in conjunction with the Lapidus procedure, thepreoperative and immediate and late postoperative first IMAmeasurements (15), the change in the first IMA, whether ornot the surgery was performed after 2003, as well as theAmerican Orthopedic Foot and Ankle Society (AOFAS)hallux–first metatarsal score (17) before and after the sur-

FIGURE 1 (A) Plantar gapping in a patient with a recurrent bunion ddepicted in Figure 1, A.

gery, and the difference between the preoperative and post-

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operative AOFAS scores. We also monitored the patientsfor the development of any postoperative complications,including infection, deep venous thrombosis (DVT), wounddehiscence, hardware failure or removal, the need for sub-sequent surgery related to the Lapidus bunionectomy, mal-union, nonunion, hallux varus, hallux limitus (defined as �10° dorsiflexion), recurrence of hallux valgus, limitations ofdaily and/or athletic activities, and limitations related to theability to wear shoe gear. Malunion was defined as exces-sive elevation or plantar displacement of the first metatarsalin the sagittal plane, a negative first IMA, or recurrence ofthe hallux valgus deformity associated with a first IMA of12° or more.

All of the clinical examinations and chart reviews, as wella telephone interviews with patients, were conducted byresearch fellows not involved with the surgery. Radiographswere obtained for all of the patients preoperatively, imme-diately postoperative, 4 to 6 weeks postoperative, 8 to 12weeks postoperative, and at 1 and 2 years postoperative.Radiographic measurement of the first IMA, as well asassessment of the status of the first MCJ arthrodesis, wasperformed by the senior author (A.S.). A radiologist and aresearch fellow, neither of whom participated in any aspectof patient care, then confirmed the radiographic assessmentsfor the retrospective and prospective components of theinvestigation. Successful fusion was defined as the presence

mity. (B) Weight-bearing anteroposterior radiograph of same patient

efor

of bony trabeculation across the first tarsometatarsal arth-

LUME 48, NUMBER 2, MARCH/APRIL 2009 171

rodesis, as well as the clinical absence of pain and motion atthe fusion site. As part of the senior author’s (A.S.) routinepractice, the AOFAS hallux–first metatarsal scoring scalehas been administered before and after bunionectomy sinceJanuary of 2001, and these scores were used for the retro-spective (crossed screws) component of this investigation.A blind investigator administered the AOFAS hallux–firstmetatarsal rating scale for the patients receiving the plateand screw fixation, as part of the prospective component ofthis investigation. Moreover, for the prospective element ofthis investigation, research fellows who did not participatein the operative procedures, after the surgeon had evaluatedthe patient, undertook postoperative clinical assessments.Care was taken to keep the surgeon’s documentation of thepatients’ postoperative progress from the view of the blindassessor.

Surgical Procedures

A skin incision was made along the dorsomedial aspect ofthe foot, extending from the base of the proximal phalanx ofthe hallux to the proximal aspect of the medial cuneiform,over the midsagittal level of the MCJ. The medial eminencewas resected from the head of the first metatarsal and savedfor possible use as a bone graft. Transection of the adductortendon, lateral collateral ligament, and extensor hallucisbrevis was performed through the dorsomedial incision atthe level of the first MTPJ, using a retractor to hold theextensor hallucis longus medially and exposing the lateralportion of the joint. The proximal portion of the incisionwas deepened using sharp and blunt dissection to exposeand disarticulate the first MCJ, while preserving the inser-tion of tibialis anterior. The articular surfaces of the MCJwere resected using a sagittal saw. After reducing the firstIMA by means of translocation of the metatarsal segment,and wedging of the joint resection as needed, temporaryfixation of the Lapidus fusion was achieved using 0.062-inch Kirschner wires. Depending on the congruity and ap-position of the arthrodesis interface, autogenous corticocan-cellous bone from the resection of the medial eminence ofthe first metatarsal head was used to pack the fusion site.The first K-wire was placed from the first metatarsal to themedial cuneiform and a second was inserted from the firstmetatarsal to the second metatarsal. Once adequate reduc-tion of the IMA was confirmed by direct visualization andimage intensification fluoroscopy, a 3.5-mm cortical plantarlag screw was placed from the first metatarsal through themedial cuneiform. Countersinking for the screw was donevery carefully with a rotary burr, which was performed firstat the plantar “flare” of the first metatarsal (inferior junctionof the shaft and base). A 3.5-mm overdrill was created if thecortical bone was very firm, drilling from the first metatarsal

flare toward, but not into, the medial cuneiform; however, in

172 THE JOURNAL OF FOOT & ANKLE SURGERY

most cases this was not needed. Next, a 2.5-mm drill wasused to create a hole extending from the distal, plantarme-dial aspect of the first metatarsal, drilling in a proximal,dorsal, and lateral direction, after which a 3.5-mm plantarlag screw was placed in this direction to achieve interfrag-mental compression between the medial cuneiform and thebase of the first metatarsal. If significant first ray hypermo-bility, or osteopenic bone, was encountered, then the plantarscrew was positioned so that it crossed the intercuneiformjoint between the first and second cuneiforms, and pur-chased bone in the second (intermediate) cuneiform.

After confirmation of the alignment and stability of theinterfragmental lag screw, the temporary fixation wasremoved and a Darco Modular Rearfoot System (MRS)LPS Lapidus Plating System (Wright Medical Technol-ogy, Inc., Arlington, TN) locking plate was applied dor-somedially across the fusion site with the 2 proximalscrews inserted through the plate, followed by placementof 1 or 2 distal screws (Figure 2). One screw was placeddistal to the arthrodesis only if placement of the plantardistal screw was blocked by the previously placed plantarlag screw. For the patients undergoing fixation withcrossed lag screws, the dissection and preparation of thefusion interface proceeded as described above for theplate and lag screw fixation. However, rather than fixat-ing the fusion with the plantar lag screw and lockingplate, 2 crossed 3.5-mm cortical thread, solid core, tita-nium screws were applied in lag fashion, the first beingdirected from the plantarmedial aspect of the first meta-tarsal base into the medial cuneiform, and the secondbeing directed from the dorsolateral aspect of the firstmetatarsal base into the medial cuneiform (Figure 3).Regardless of the method of osteosynthesis, and afterdetermining whether or not additional autogenous bonegraft was needed (Figure 4), the wound was closed in

FIGURE 2 Intraoperative temporary fixation of arthrodesis site and

locking plate.

anatomical layers and a dry sterile dressing and below-the-knee immobilizing splint were applied with the footat a right angle to the leg.

The postoperative course varied based on the form of osteo-synthesis used for fixation of the Lapidus fusion. The patients whoreceived plantar lag screw with locking plate fixation werekept non–weight bearing in a below-the-knee cast or immo-bilizing boot for the first 4 postoperative weeks. Radio-graphs were taken at the 4-week postoperative visit and, if

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sufficient fusion consolidation had occurred, the patient wasallowed to resume full weight-bearing ambulation with theuse of an immobilizing, removable cast boot for an addi-tional 4 to 6 weeks, or until follow-up radiographs revealedcomplete consolidation of the fusion mass, and the patientwas pain-free upon clinical examination. It should be notedthe this postoperative protocol was more restrictive than theone recommended by the manufacturer of the locking plate,which specified immediate postoperative weight bearing in

FIGURE 3 Postoperative radio-graphs depicting crossed screw fix-ation. (A) Anteroposterior. (B) Lat-eral.

FIGURE 4 Lapidus fixated with alocking plate and a plantar lagscrew. (A) Preoperative anteropos-terior view. (B) Two-month postop-

erative anteroposterior radiograph.

LUME 48, NUMBER 2, MARCH/APRIL 2009 173

an angled (forefoot load-reducing) shoe. For those patientsreceiving crossed lag screw fixation, a non–weight-bearingbelow-the-knee cast was used for a minimum of 6 weeks.The postoperative protocol for the patients with screw fix-ation entailed non–weight bearing in a below-the-knee castor cast boot for at least 6 weeks, or until radiographic andclinical inspection revealed solid arthrodesis. Patients inboth groups were allowed to begin great toe range of motion(ROM) exercises at 3 weeks postoperative, and ankle ROMexercises at 6 weeks into the postoperative period. Bothgroups were able to remove the below-knee cast boot forsleeping, bathing, and icing after exercise by 6 weeks aftersurgery and began formal physical therapy at 8 to 10 weeksif it was indicated based on limited first MTPJ ROM.

Statistical Plan

After describing the data statistically, we used Student ttest and Fisher’s exact test to identify statistically significantdifferences. We also used generalized estimation equationsand logistic regression to determine the influence that inde-pendent variables had on 2 dependent outcomes of interest,namely a late postoperative first IMA less than 12° or lessthan 9°, and whether or not any complication was observedin the postoperative period. Finally, we used Tukey’s posthoc test to determine whether or not we had sufficientsample size to detect statistically significant differences fora number of outcomes by the method of fixation. Statisticalanalyses were performed using SyStat (Cranes SoftwareInternational, Bangalore, India), and Stata/SE 9.2 forMacintosh (Stata Corporation, College Station, TX) soft-ware on a personal computer, and statistical significancewas defined at the 5% (P � .05) level.

Results

After reviewing the records of the patients who under-went crossed screw fixation and prospectively collectingdata on those patients who underwent plantar lag screw withlocking plate fixation for bunionectomy by means of Lapi-dus arthrodesis between August 2001 and May 2006, 41patients were identified, of which 1 failed to meet theinclusion criteria of at least a 12-month follow-up exami-nation, thereby leaving a total of 40 patients eligible forinclusion in the investigation. The patient who was ex-cluded was last evaluated at 5 months following Lapidusfusion, at which time the patient displayed evidence of adelayed union. The statistical description of the final datasetis depicted in Table 1. The mean overall duration of fol-low-up was 39.1 � 17.3 months. There were 34 (85%)female and 6 (15%) male patients, and the mean age was53.4 � 15.05 years. The mean overall preoperative first

IMA was 15.3° � 2.32°, the immediate postoperative first

174 THE JOURNAL OF FOOT & ANKLE SURGERY

IMA was 4.73° � 2.81°, and the late follow-up first IMAwas 5.03° � 2.86°. The reductions between the preoperativeand immediate and late postoperative first IMAs were sta-tistically significant (P � .0001) (Table 2), and the meanoverall reduction between the preoperative and late postop-erative first IMA was 10.23° � 3.05° (Table 1). The meanoverall preoperative AOFAS hallux–first metatarsal was41.75 � 2.52, whereas the postoperative score was 90.48 �8.41; this difference was statistically significant (P � .0001)(Table 2), and the mean overall increase between the pre-operative and postoperative AOFAS scores was 48.73 �8.72 (Table 1). Table 1 also indicates that 21 (52.5%) of thecases were performed on the right foot, 3 (7.5%) of thepatients had undergone a prior ipsilateral bunionectomy,and 14 (35%) underwent a concomitant Akin proximalphalangeal osteotomy in conjunction with the Lapidus ar-throdesis. The only complications observed in the overallcohort were 2 (5.0%) patients with postoperative halluxlimitus (� 10°), 3 (7.5%) patients with painful internal

TABLE 1 Statistical description of the overall dataset (N �40 Lapidus procedures in 40 patients)

Variable Mean � SD forcontinuous

variables, or count(%) for categorical

variables

Age, y 53.43 � 15.05Male sex 6 (15)Right side 21 (52.50)Prior bunionectomy 3 (7.5)Adjunct Akin osteotomy 14 (35)Preoperative first IMA (°) 15.3 � 2.32Immediate postoperative first IMA (°) 4.73 � 2.81Late postoperative first IMA (°) 5.03 � 2.86Difference between preoperative and

immediate postoperative first IMA (°)10.58 � 3.15

Difference between preoperative and latepostoperative first IMA (°)

10.23 � 3.05

Difference between immediate and latepostoperative first IMA (°)

0.3 � 0.7579

Postoperative hallux limitus (� 10°dorsiflexion)

2 (5)

Painful deep metal fixation requiring removal 3 (7.5)Malunion 1 (2.5)Nonunion 1 (2.5)Only wears comfort shoes postoperative 2 (5)Any postoperative complication 9 (22.5)Surgery performed after 2003 23 (57.50)Preoperative AOFAS score 41.75 � 2.52Postoperative AOFAS score 90.48 � 8.41Difference between preoperative and

postoperative AOFAS score48.73 � 8.72

Follow-up duration, mo 39.1 � 17.3

Abbreviation: AOFAS, American Orthopedic Foot and Ankle Soci-ety; IMA, intermetatarsal angle; SD, standard deviation.

fixation devices that required removal, 1 (2.5%) malunion,

1 (2.5%) nonunion, and 2 (5.0%) patients who used only acomfort shoe (soft, wide, supportive) following the surgery;and the overall prevalence of postoperative complicationswas 9 (22.5%) patients (Table 1). Table 3 displays theindependent variables that statistically describe the patientsin the 2 different fixation groups, and indicates whether ornot the differences were statistically significant. The onlyvariables that were statistically significantly different be-tween the fixation groups were whether or not the patientsunderwent a concomitant Akin osteotomy along with theLapidus procedure (P � .046), whether or not the surgerywas performed after 2003 (P � .0001), and the preoperativeAOFAS score (P � .0282) (Table 3). Furthermore, all ofour patients were either active or very active (athletes) (datanot shown). Of the 25 patients active in sports from bothgroups (ranging from hiking to impact sports such as run-ning, aerobics, and tennis), all were able to return to theirdesired activities. There were no “sedentary” patients in theentire cohort. The mean duration of time to return to sportswas 17.3 � 3.2 weeks. There was no statistically significantdifference between the 2 groups as to their RTA, 16.9 � 3.3weeks for the group with screws versus 17.7 � 3.4 weeksfor those with plates (P � .55).

Defining the dependent variable as a late postoperativefirst IMA that ranged from less than 12° to less than 10°, oras the absence of any form of postoperative complication,we found no independent variables from Table 1 that werestatistically significantly associated with either of the de-pendent outcomes using generalized estimation equationsand univariate logistic regression (results not shown). How-ever, statistically significant independent variables associ-ated with a late postoperative first IMA of less than 9° werethe immediate postoperative first IMA, where each 1° in-crease in the immediate postoperative first IMA decreasedthe likelihood that the late postoperative first IMA would beless than 9° (odds ratio � 0.3465, 95% confidence interval �0.1512 to 0.794); the change in the IMA between the pre-operative and immediate postoperative periods, where each1° reduction in the IMA increased the likelihood that thelate postoperative IMA would be less than 9° (odds ratio �

TABLE 2 Comparison of preoperative to postoperativeoverall mean outcomes (N � 40 procedures in 40 patients)

Outcome Preoperative Postoperative P Value*

Immediate Late

First IMA (°) 15.3 � 2.32 4.73 � 2.81 �.00015.03 � 2.86 �.0001

4.73 � 2.81 5.03 � 2.86 .0166AOFAS score 41.75 � 2.52 90.48 � 8.41 �.0001

Abbreviations: AOFAS, American Orthopedic Foot and Ankle So-ciety; IMA, intermetatarsal angle.*Paired Student t test.

1.626, 95% confidence interval � 1.0744 to 2.4605); and

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the change in the IMA between the preoperative and latepostoperative periods, where each 1° reduction in the IMAincreased the likelihood that the late postoperative IMAwould be less than 9° (odds ratio � 2.0197, 95% confidenceinterval � 1.1852 to 3.4417). Furthermore, we found noevidence of any statistically significant associations thatcould explain either of these outcomes (any complication, apostoperative first IMA �12°, or a postoperative first IMA�9°), when multiple variable logistic regression and gen-eralized estimation equations were modeled (results notshown). Still further, using logistic regression and general-ized estimation equations, we observed confounding be-tween fixation with crossed lag screws and use of theadjunct Akin osteotomy, as well as the date of surgerytaking place before the start of 2004. In regard to the otherindependent variables, namely any measurement of the firstIMA, preoperative or postoperative AOFAS hallux score, orany form of postoperative complication, we found no evi-dence of confounding or interaction (effect modification).

Discussion

Our initial interest in the use of the locking plate with thesingle plantar lag screw began late in 2003, when we weremade aware (Ernst Orthner, MD, Wels, Austria, written andoral communication, December 4, 2003) that this form ofLapidus arthrodesis allowed earlier weight bearing (4weeks) in comparison to the more traditional screw fixation(6 weeks). Based on our interest in trying to safely initiateweight bearing earlier in the postoperative period followingLapidus arthrodesis, late in 2003 we decided to pursuefixation of the arthrodesis using a plantar lag screw com-bined with a dorsomedial locking plate. For this reason,inspection of our results showed a statistically significant (P� .0001) shift toward this method of fixation after 2003(Table 3), at which time we decided to prospectively eval-uate the patients undergoing this form of Lapidus fusion,and to compare them to a series of patients who had alreadyundergone Lapidus arthrodesis using crossed lag screw fix-ation. The results of our study indicated that use of a lockingplate in conjunction with a plantar lag screw resulted insuccessful healing that did not appear to be compromisedwhen weight bearing was initiated at 4 weeks postoperative,as compared to the use of crossed screw fixation and avoid-ing weight bearing until the more traditional 6-week pointinto the postoperative phase. Still further, it is evident thatthe operating surgeon (A.S.) determined intraoperativelythat the adjunct use of the Akin proximal hallucial phalan-geal osteotomy was not typically required in associationwith the use of the plantar screw–locking plate construct,and for this reason we noted a statistically significant (P �.046) reduction in the use of the Akin after the start of 2004.

The exact explanation for this shift away from the use of the

LUME 48, NUMBER 2, MARCH/APRIL 2009 175

Akin stemmed from the surgeon’s impression that use of thelag screw and plate construct provided a more secure formof osteosynthesis that would hold up better over time, al-though this bias could not be further elucidated based on ourdata and, interestingly, there was no statistically significantdifference between the amount of first IMA correctionachieved between the different methods of fixation. It wasalso interesting to note that the preoperative AOFAS scorewas statistically significantly (P � .0282) higher in theplantar lag screw–locking plate fixation group, although therelationship of this observation to the outcomes observed,overall and by method of Lapidus fixation, is not entirelyclear since we found no statistically significant independentvariable, or combination of variables, that could explain thisobservation. Therefore, this relationship brings into ques-tion whether or not those in the plantar screw–locking platefixation group may have scored relatively higher on thepostoperative AOFAS scale than did those in the crossedscrew fixation group because they started at a higher base-line AOFAS score. Here, too, despite our efforts to analyt-

TABLE 3 Comparison of independent and outcome variables

Variable C

Age, yearsAge � 40 yearsAge 40–60 yearsAge � 60 yearsMale sex, count (%)Right side, count (%)Prior bunionectomy, count (%)Adjunct Akin osteotomy, count (%)Preoperative first IMA (°)Immediate postoperative first IMA (°)Late postoperative first IMA (°)Difference between preoperative and immediate

postoperative first IMA (°)Difference between preoperative and late postoperative

first IMA (°)Difference between immediate and late postoperative

first IMA (°)Postoperative hallux limitus (� 10° dorsiflexion)Painful deep metal fixation requiring removal, count (%)Malunion, count (%)Nonunion, count (%)Only wears comfort shoes postoperativeAny postoperative complicationSurgery performed after 2003, count (%)Preoperative AOFAS scorePostoperative AOFAS scoreDifference between preoperative and postoperative

AOFAS scoreDuration of follow-up, months

Abbreviations: AOFAS, American Orthopedic Foot and Ankle Soci*Unpaired Student t test.†Fisher’s exact test.

ically elucidate the nature of this relationship, we were not

176 THE JOURNAL OF FOOT & ANKLE SURGERY

able to formulate a precise conclusion based on our data,and this may have been a result of too small a sample size.However, in an effort to assess the statistical power to detecta significant difference in regard to the postoperative AO-FAS score, should one have been present, we used Tukey’shonestly significant difference (HSD) post hoc test, whichindicated that our sample size was sufficiently large toidentify a statistically significant difference (total degrees offreedom � 39, possible treatments � 2, critical value �2.86, Tukey HSD � 7.5471143). We also calculatedTukey’s HSD in regard to the amount of correction of thefirst IMA between the different fixation groups, and againconcluded that our sample size was sufficiently large toidentify a statistically significant difference (total degrees offreedom � 39, possible treatments � 2, critical value �2.86, Tukey HSD � 2.980363). In regard to the logisticregression analyses, it is understandable that the amount ofreduction between the preoperative and the immediate andlate postoperative first IMA would be statistically signifi-cantly associated with the postoperative first IMA, although

ethod of fixation (N � 40 procedures in 40 patients)

ed lag screws(n � 19)

Plate with plantar lagscrew (n � 21)

P Value

.84 � 10.76 50.33 � 17.79 .1752*2 (10.53) 5 (23.81) .412†7 (36.84) 7 (33.33) .9999†

10 (52.63) 9 (42.86) .5752†4 (21.05) 2 (9.52) .398†8 (42.11) 13 (61.90) .342†

0 3 (14.29) .233†10 (52.63) 4 (19.05) .046†.63 � 2.77 15 � 1.84 .3974*.53 � 2.97 4 � 2.52 .0863*5.9 � 2.96 4.24 � 2.59 .0666*.11 � 3.28 11 � 3.03 .3758*

.74 � 3.11 10.76 � 2.98 .2938*

.37 � 1.01 0.24 � 0.44 .186†

1 (5.26) 1 (4.76) .9999†2 (10.53) 1 (4.76) .596†

0 1 (4.76) .999†1 (5.26) 0 .475†1 (5.26) 1 (4.76) .731†4 (21.05) 5 (23.81) .9999†2 (10.53) 21 (100) �.0001†

.84 � 2.48 42.57 � 2.32 .0282*9.9 � 11.29 91 � 4.74 .6835*.05 � 11.83 48.43 � 4.73 .8246*

3.4 � 11.9 24.9 � 6.7 �0.001

MA, intermetatarsal angle.

by m

ross

56

155

10

9

0

408

49

5

ety; I

it is interesting to note that the statistical significance of this

relationship was not observed until the dependent variable wasdefined as a postoperative first IMA of less than 9°. Theobserved confounding between fixation with crossed lagscrews and use of the adjunct Akin osteotomy, as well as thedate of surgery taking place before the start of 2004, is easilyunderstood after consideration of our biased approach to theuse of the different fixation constructs, as described above.

Our overall results revealed a number of interesting sim-ilarities and differences with other studies that have ana-lyzed the use of the Lapidus procedure to correct halluxabductovalgus. Previous studies have reported the preva-lence of nonunion following the Lapidus procedure to rangefrom 0% to 12% (1–3, 5–12). In the crossed screw fixationgroup described in this article, we observed 1 asymptomaticnonunion that had initially been interpreted as fused basedon radiographic and clinical examinations, another non-union that united after immobilization and electrical bonegrowth stimulation, and a third case that involved a femalepatient who was lost to follow-up before the inclusionrequirement of at least a 12-month postoperative follow-upradiographic and clinical examination. Had this particularpatient been followed to at least 1 year into the postopera-tive phase, she may have displayed solid union; however,we can only speculate as to the ultimate status of thearthrodesis. By omitting this patient from the final analysis,we may have biased our results such that our reportedprevalence of nonunion may be lower than what it should,in actuality, be. All of these observations underscore theimportance of sustaining postoperative follow-up examina-tions for a suitably long enough period of time to be able tobe assured of the healing status of bone, and makes usconsider with greater scrutiny other studies that reportshorter radiographic evaluation periods, such as the inves-tigation described by Patel et al (10).

It was also interesting to note that the overall mean differ-ence in first IMA between the immediate and late postopera-tive periods was 0.3° � 0.7579° (Table 1), a range of valuesthat is not likely to be clinically significant, although it was

TABLE 4 Comparison of preoperative to postoperative mean

Fixation group Outcome

Crossed lag screws (n � 19) First IMA (°)

AOFAS scorePlantar lag screw with locking plate (n � 21) First IMA (°)

AOFAS score

Abbreviations: AOFAS, American Orthopedic Foot and Ankle Soci*Paired Student t test.

statistically significant (P � .0166) (Table 2). By the same

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token, the difference in first IMA between the immediate andlate postoperative periods for the crossed screw fixation groupwas 0.37° � 1.01° (Table 3), also a range of values that is notlikely to be clinically significant, although it was statisticallysignificant (P � .1298) (Table 4). The difference in first IMAbetween the immediate and late postoperative periods for theplantar lag screw–locking plate fixation group was 0.24° �0.44° (Table 3), again, a range of values that is not likely to beclinically significant, although it was statistically significant (P� .1212) (Table 4). These clinically small differences betweenthe immediate and late postoperative first IMAs suggest thatcorrection of the first IMA by means of Lapidus fusion holdsup over time, a finding that was also observed by Coetzee andWickum (5). Although we noted statistically significant in-creases in the first IMA (loss of correction) between the im-mediate and late postoperative measurements for the overall(Table 2) and different fixation groups (Table 4), we did notconsider these differences to be clinically significant since themaximum loss was 0.37° � 1.01° (Table 3), as observed in thecrossed screw fixation group. The statistical significance of thisobservation was probably related to 2 primary reasons, namelythe fact that the outcome was measured as a continuous nu-meric variable (°), and the sample size for each treatment group(crossed screw, n � 19; lag screw with locking plate, n � 21)was sufficiently large.

The Lapidus procedure has been scrutinized by other inves-tigators in regard to its use for repair of the deformity of halluxvalgus. Some of these prior investigations have mentionedconcomitant use of the Akin osteotomy in some of the cases;however, these reports did not always describe the influence ofthe arthrodesis on the hallux abductus (valgus) angle (5, 8, 10).In our investigation, we purposely did not focus attention onthe hallux valgus angle; rather, instead, we focused attention onthe first IMA, thinking that it would serve as a more directrepresentation of the effect of the Lapidus arthrodesis on thestructural alignment of the foot. The fact that we observed asharp reduction in the use of a concomitant Akin osteotomywhen we started to use the plantar lag screw–locking plate

omes, by fixation group (N � 40 procedures in 40 patients)

Preoperative Postoperative P Value*

Immediate Late

15.63 � 2.77 5.53 � 2.97 �.000115.63 � 2.77 5.9 � 2.96 �.0001

5.53 � 2.97 5.9 � 2.96 .129840.84 � 2.48 89.9 � 11.29 �.0001

15 � 1.84 4 � 2.52 �.000115 � 1.84 4.24 � 2.59 �.0001

4 � 2.52 4.24 � 2.59 .021242.57 � 2.32 91 � 4.74 �.0001

MA, intermetatarsal angle.

outc

ety; I

fixation construct early in 2004, suggests that we felt that this

LUME 48, NUMBER 2, MARCH/APRIL 2009 177

ction

form of fixation was associated with a greater degree of, and amore lasting, correction. This bias was not supported by theresults of our investigation.

In regard to reduction of the first IMA, we observed areduction of 10.23° � 3.05° between the preoperative andlate postoperative measurements, and this amount of cor-rection appears to be in keeping with the 8° to 10° reportedin a number of previously published studies (Table 5) (1–12). An informal analysis of the results of 8 previouslypublished reports (Table 6) (1, 2, 5, 7–9, 11, 12) revealed amean preoperative first IMA of 16.3° � 3.1°, a meanpostoperative first IMA of 6.7° � 2.4°, and a mean preva-lence of nonunion of 6.7% � 4.5%. In our investigation, weobserved an overall mean preoperative first IMA of 15.3° �2.32°, a mean late postoperative first IMA of 5.03° � 2.86°,and a prevalence of nonunion of 1 (2.5)% (Table 1). Al-though we appreciate the fact that such a crude comparisonfails to take into consideration the potential influence of

TABLE 5 Results of previously published investigations comp

Author/s(year)*

Patients(Feet)

Fixation First IM

Clark et al(1987)

16 (24) 2 screws (m1-c and m1-m2) 10.9, 4.

Sangeorzan &Hansen(1989)

32 (40) 2 screws (m1-c and m1-m2) 14,

Myerson et al(1992)

53 (67) 2 screws (m1-c and m1-m2) 14.3, 5.

Grace et al(1999)

23 (30) Parallel 4.0 cancellous orcannulated screws (m1-c)

13.3, 5.

Catanzariti etal (1999)

39 (47) Parallel 4.0 mm cancellousor cannulated screws(m1-c)

13.8, 2.

Bednarz &Manoli(2000)

26 (31) 2.0 � 3.5-mm bicorticalscrews (c-m1 and m1-m2)

18,

McInnes &Bouche(2001)

25 (32) Crossing bicortical orcannulated screws

16.7, 8.

Patel et al(2004)

211 (227) Crossing 3.5 mm bicorticalscrews, � 3rd screw (m1-c)

Not rep

Rink-Brune(2004)

106 (106) Parallel 3.5 mm cannulatedscrew and K-wire

22.5, 10.

Coetzee &Wickum(2004)

91 (105) 2.0 � 3.5-mm bicorticalscrews (c-m1 and m1-m2)

18, 8.

Current Study 19 (19) 2 crossed lag screws (bothm1-c)

15.6, 5.

21 (21) 1 lag screw (m1-c) & lockingplate with 2–4 screws

15,

Abbreviations: c, medial cuneiform; DVT, deep vein thrombosis; HWmetatarsal; NWB, non–weight bearing; RSDS, reflex sympathetic d*Full citation provided in the list of references.†Preoperative, postoperative (preoperative � postoperative � redu

heterogeneity in regard to the pooled data, we feel that

178 THE JOURNAL OF FOOT & ANKLE SURGERY

comparison of our results to a number of previously pub-lished reports puts our findings into perspective and enablessurgeons to better understand what can be expected whenthe Lapidus arthrodesis is used to treat hallux valgus.

It should also be noted that Cohen and colleagues (18)showed that 2 crossed lag screws provided substantially stron-ger fixation of a Lapidus arthrodesis in a cadaveric bone modelthan did the use of a locking plate without an adjunct plantarlag screw. We feel that the addition of the plantar lag screwmakes a critical difference when the Lapidus procedure isundertaken, particularly when patients are encouraged toweight bear sooner than the typical 6 weeks of non–weightbearing. The only way to be certain of this assumption, how-ever, would be to directly compare the use of the locking platewith and without the addition of the plantar lag screw. Wewere also satisfied to note that, contrary to another study (8),following Lapidus arthrodesis our athletic patients were allable to participate in their desired sports, including running and

to the current investigation

) Postoperativecourse

Prevalence (count) of allcomplications

Prevalence ofnonunion, %

) 2 wk NWB, 2 wkpartial WB, 4 wkWB

Not reported 0.0

2 wk NWB, 2 wkpartial WB

4 non/delayed union 10.0

) 6 wk cast/WB 7 pin tract, 3 elevatus, 7nonunions, 1 varus

9.5

) 6–8 wk NWB 1 nonunion, 3 elevatus,2 varus

3.3

.7) 6–8 wk NWB 2 delayed, 3 nonunions,4 sub 2nd lesions,

10.6

) 2 wk NWB, 2–6 wkpartial WB†

5 recurrence, 2metatarsalgia, 1 DVT

0.0

) 6 wk NWB 2 delayed, 5 nonunions,4 varus

12.0

6 wk NWB 14 delayed, 12nonunions

5.3

.4) 6–8 wk NWB 17 delayed, 2nonunions, 1 DVT, 3RSDS

2.0

) 6 wk NWB 7 nonunions, 5 lostcorrection

6.0

.1) 6 wk NWB, 4 wkWB boot

1 nonunion, 1 HWfailure, 2 HW removal

2.5

) 4 wk NWB, 4 wkWB boot

1 malunion, 1 HWremoval

0.0

dware; IMA, intermetatarsal angle; m1, first metatarsal; m2, secondphy syndrome; WB, weight bearing.

).

ared

A† (°

2 (6.7

6 (8)

8 (8.5

4 (7.9

1 (11

8 (10

2 (8.5

orted

1 (12

2 (9.8

5 (10

4 (11

, harystro

tennis. We should point out, however, that we used the results

of this previous publication as a basis from which to considerother surgical options for high-level athletes suffering with alarge bunion deformity, of which there were none (high-levelathletes) in our cohort.

Based on the results of this investigation, we conclude thatthe Lapidus procedure provides a useful method for the surgi-cal repair of the deformity of hallux abductovalgus when thefirst IMA measures approximately 15°, and a mean overallpostoperative AOFAS score of 90.48 � 8.41 can be achieved.Furthermore, the use of a plantar lag screw combined with adorsomedial locking plate enables patients to resume weightbearing at 4 weeks postoperative, without encountering statis-tically significant increases in postoperative complications or areduction in the postoperative AOFAS score. The findings thatwe have made in this preliminary investigation can be used inthe development of future randomized controlled trials andprospective cohort studies that explore the use of the Lapidusarthrodesis for correction of hallux valgus.

References

1. Bednarz PA, Manoli A 2nd. Modified Lapidus procedure for the treatment

TABLE 6 Selected previous investigations

Author (year)* Preoperativefirst IMA (°)

Postoperativefirst IMA (°)

% Nonunion

Sangeorzan & Hansen(1989)

14 6 10

Myerson et al. (1992) 14.3 5.8 9.5Grace et al. (1999) 13.3 5.4 3.3Catanzariti et al.

(1999)13.8 2.1 10.6

Bednarz & Manoli(2000)

18 8 0

McInnes & Bouche(2001)

16.7 8.2 12

Rink-Brune (2004) 22.5 10.1 2Coetzee & Wickum

(2004)18 8.2 6

Mean � SD 16.3 � 3.1 6.7 � 2.4 6.7 � 4.5

Abbreviation: IMA, intermetatarsal angle.*Full citation provided in the list of references.

of hypermobile hallux valgus. Foot Ankle Int 21:816–821, 2000.

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2. Catanzariti AR, Mendicino RW, Lee MS, Gallina MR. The modifiedLapidus arthrodesis: a retrospective analysis. J Foot Ankle Surg 38:322–332, 1999.

3. Clark HR, Veith RG, Hansen ST Jr. Adolescent bunions treated bythe modified Lapidus procedure. Bull Hosp Joint Dis 47:109 –122,1987.

4. Chiodo CP, Schon LC, Myerson MS. Clinical results with the Ludloffosteotomy for correction of adult hallux valgus. Foot Ankle Int 25:532–536, 2004.

5. Coetzee JC, Wickum D. The Lapidus procedure: a prospective cohortoutcome study. Foot Ankle Int 25:526–531, 2004.

6. Coetzee JC, Resig SG, Kuskowski M, Saleh KJ. The Lapidus proce-dure as salvage after failed surgical treatment of hallux valgus. Sur-gical technique. J Bone Joint Surg Am 85-A:60–65, 2004.

7. Grace D, Delmonte R, Catanzariti AR, Hofbauer M. Modified Lapidusarthrodesis for adolescent hallux abductovalgus. J Foot Ankle Surg38:8–13, 1999.

8. McInnes BD, Bouche RT. Critical evaluation of the modified Lapidusprocedure. J Foot Ankle Surg 40:71–90, 2001.

9. Myerson M, Allon S, McGarvey W. Metatarsocuneiform arthrodesisfor management of hallux valgus and metatarsus primus varus. FootAnkle 13:107–115, 1992.

10. Patel S, Ford LA, Etcheverry J, Rush SM, Hamilton GA. ModifiedLapidus arthrodesis: rate of nonunion in 227 cases. J Foot Ankle Surg43:37–42, 2004.

11. Rink-Brune O. Lapidus arthrodesis for management of hallux val-gus—a retrospective review of 106 cases. J Foot Ankle Surg 43:290–295, 2004.

12. Sangeorzan BJ, Hansen ST Jr. Modified Lapidus procedure for halluxvalgus. Foot Ankle 9:262–266, 1989.

13. Saxena A, McCammon D. The Ludloff osteotomy: a critical analysis.J Foot Ankle Surg 36:100–105, 1997.

14. Stamatis ED, Navid DO, Parks BG, Myerson MS. Strength of fixation ofLudloff metatarsal osteotomy utilizing three different types of Kirschnerwires: a biomechanical study. Foot Ankle Int 24:805–811, 2003.

15. Coughlin MJ, Saltzman CL, Nunley JA II. Angular measurements inthe evaluation of hallux valgus deformities: a report of the ad hoccommittee of the American Orthopedic Foot and Ankle Society onangular measurements. Foot Ankle Int 23:68–74, 2002.

16. Wynn-Davies R. Acetabular dysplasia and familial joint laxity: twoetiological factors in congenital dislocation of the hip. A review of589 patients and their families. J Bone Joint Surg Br 52-B(4):704 –716, 1970.

17. Kitaoka HB, Alexander IJ, Adelaar RS, Nunley JA, Myerson MS,Sanders M. Clinical rating systems for the ankle-hindfoot, midfoot,hallux, and lesser toes. Foot Ankle Int 15:349–353, 1994.

18. Cohen DA, Parks BG, Schon LC. Screw fixation compared to H-locking plate fixation for first metatarsocuneiform arthrodesis: a bio-

mechanical study. Foot Ankle Int 26:984–989, 2005.

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