Critical evaluation of the modified lapidus procedure

Critical Evaluation of the Modified Lapidus Procedure Brian D. Mcinnes, DPM, AACFAS, and Richard T. Bouche, DPM, FACFAS The modified Lapidus procedure has been used for treatment of hallux abducto valgus for many years, yet only a handful of reports evaluate procedure outcome. The purpose of this investigation was twofold: 1) to provide a retrospective outcome analysis of the modified Lapidus procedure using subjective and objective criteria, and 2) to evaluate procedure outcome in patient popula tions with differing functional demands: athletes, active patients, and sedentary patients. Thirty-four patients (42 feet) had the modified Lapidus procedure performed by the senior author (R. T.B.) over a 7-year period. Nine patients were lost to follow-up leaving 25 patients (32 feet) for study inclusion. Twentythree females and two males with average age 44.4 years (range 15- 71 years) were evaluated at an average follow-up time of 39 months (range 13-91 months). Evaluation consisted of subjective questionnaire, physical examination, and radiographic assessment. Subjective evaluation revealed that 78% of patients rated surgery " completely " or "very" effective. Athletes demonstrated lower return to preoperative activity levels (30%) than did active patients (86 %) and sedentary patients (75 %), but this was not statistically significant. Seventy-seven percent of athletes rated surgery "c ompletely" or " very" effective. Postoperative intermetatarsal angle averaged 8.2 ° (range - 2 to 15) and first metatarsophalangeal joint dorsiflexion averaged 62.6° (range 20 °-90°). Intermetatarsal angle correction to 10° or less and postoperative first metatarso-phalangeal joint dorsiflexion 45° or greater correlated with improved subjective results. The modified Lapidus procedure is an effective procedure in patients with hypermobility of the first metatarsocuneiform joint. Success is dependent on patient selection, meticulous surgical technique and comprehensive postoperative management. (The Journal of Foot & Ankle Surgery 40(2):71-90,2001 ) Key words: athlete, first metatarsocuneiform arthrodesis, hallux valgus , hype rmobility, Lapidus

The Lapidus proced ure has been used for treatm ent of hallu x abducto valgus for nearly a century . Altho ug h named after Paul Lapi du s, the proc ed ure was origin ally described by Albrecht in 1911 , well before Lapidus wrote his first papers in 1934 ( 1, 2) . As originally described , the procedure involves arthro des is of the first rnetatarsocune iform joint (MCJ) and the first and second metatarsal bases (2) . Presently, most surgeo ns perform a modi ficat ion of the ori gin al procedure, omitting arth rod esis between the met atarsal bases. Altho ugh Albrec ht Tru slow, and Kleinberg all de scr ibed first MCl arth rod esis prior to Lapidus, the pro cedure does not bear their nam es ( 1-6). Thi s is likely due to Lapidu s pop ulari zing the pro cedure with three articles writte n fro m 1934 to 1959 (2, 4, 5). Th ese three articles discu ssed proced ure rationale and outlined surgical technique. Lapidus belie ved that hallu x abducto valgus developed as a res ult of met atarsus primu s adductus (La pidus From the Virginia Mason Med ical Center, Seattle, \VA. Address correspondence to: Brian D. Mcin nes, DPM, 100 NE Gilman Blvd.. Issaquah, \VA 98027 . E-mail: bikebry @hot mail.com . Received for publication November 24, 1999; accepted in revised form for publica tion Novemb er 17, 2000. T he Journal of Foot & Ankle Surgery 1067-25 16/01/4002-007 1$4.00/0 Co pyright © 2001 by the American College of Foot and Ankle Surgeons

used the term metatarsus primus varus) . Influenced by his studies in anthro pology, he co nsidered an addu cted first metata rsal in man to be an atavis tic tra it. He likened metatarsus primu s add uctus to other arrests in ont ogenic deve lopment such as hare lip, cleft palate, and undesce nded testicle. Ju st as these atavistic traits are treated surgically, so should excessive first metatarsal addu ctu s, Lapidus stated, "It is up to the surg eon to complete wh at nature failed to do" (5) . Lapidu s was also a prop onent of correcting the deformity at its ape x, whi ch he fe lt was the first MCJ. He stated, "osteoto mies of the first metatarsal, parti cul arl y over the distal part , never have see med mechani cally sound . .." (5) . Despite his man y co ntrib utions, Lapidus never publi shed any obj ec tive result s. Rath er, he stated, "after 25 years of ex pe rience . .. we still find this a useful pro cedure in properly se lected cases" and "o ur post-op erati ve res ults are most gratifying and warrant further co ntinuation of our surgical approach in bun ion cases" (4 ). Since the origin al description s by the aforem entioned authors, there have been relative ly few publicat ion s investigatin g effe cti veness of the Lapidus procedure. There has also been relatively littl e writte n regarding specific ind ication s for its use, VOLUME 40, NUMBER 2, MARCH/APRIL 2001

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Rutherford was the first podiatric surgeon to use the Lapidus procedure, performing his first case in 1941 (7). He published several articles detailing his experience in nearly 120 cases but provided little objective documentation of results (7, 8). In 1980, Butson reported a large series (78 patients, 119 feet) in which he used a modification of the Lapidus procedure (9). This modification involved using resected medial eminence from the first metatarsal head as bone graft at the arthrodesis site to prevent shortening. Time of follow-up ranged from 2 to 16 years. Results were graded as excellent, good, fair, or poor, with 92% achieving excellent or good results. In 1987, Clark et al. published a retrospective analysis of their experience using the procedure in adolescent females (10). Sixteen patients (24 feet) with an average age of 18 years were evaluated an average of 24.3 months postoperatively (range 3- 72 months). Results were graded using a modification of criteria established by Bonney and MacNab (11) with 91% achieving excellent or good results. Saffo et al. published a 5-year retrospective analysis in 1989 (12). Biplanar resection of the first MCJ was used to correct first ray malalignment. Fixation was accomplished through two crossed Kirschner wires. Forty-four patients (54 feet) were evaluated using a subjective questionnaire as well as clinical and radiographic examination. Procedures were performed by multiple surgeons and follow-up was performed by multiple investigators. In addition, the study population of 54 feet represented only 34% of the total number of feet undergoing the procedure during the 5-year period examined. It is unclear whether the other patients were lost to follow-up or simply not contacted. Patient subjective evaluation was graded as excellent, good, same, or worse, with 83% achieving excellent or good results. Sangeorzan and Hansen published their retrospective analysis in 1989 (13). Abrasional arthrodesis with occasional use of plantar and lateral planar resection was used to prepare the joint. Multiple lag screw fixation was employed, as was occasional use of bone graft. Thirtytwo patients (40 feet) with hallux valgus and hypermobile first ray were surgically treated over a 5-year period. The authors felt first ray hypermobility has defied objective characterization, but defined it as a "clinical syndrome involving relatively increased dorsiflexion of the first ray with soft end point on examination, combined with second metatarsal overload." Time of follow-up ranged from 2 to 6.5 years and patients were graded as excellent, good, fair, or poor, using subjective functional results and relief of pain. Excellent or good results were achieved in 74% of patients. Myerson et al. published their retrospective analysis in 1992 (14). Their technique involved biplanar resection from the plantar and lateral aspect of the joint (14, 15). 72

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Two screws were used for rigid internal fixation. Fiftythree patients (67 feet) underwent the procedure over a 4-year period and follow-up was excellent with 51/53 (96%) patients available for clinical review. Average time of follow-up was 28 months (range 16-49 months). Myerson et al. also pointed out the subjective nature of hypermobility and defined it as "excessive motion of the first metatarsal in both the sagittal and transverse planes." Interestingly, only 29/65 feet (45%) were noted to have hypermobility preoperatively. It appears that Myerson's use of the procedure was not limited to cases involving first ray hyperrnobility. Clinical evaluation was performed according to the American Orthopedic Foot & Ankle Society Research Committee recommendations (14). Seventy-three percent of patients had satisfactory pain relief and 79% were satisfied with appearance. In early 1999, Grace et al. published a retrospective review of the procedure in adolescent hallux valgus (16). Twenty-three patients (30 feet) with an average age of 16.5 years were reviewed an average of 61 months postoperatively (range 7 -161 months). Follow-up consisted of telephone interview, chart review, and review of 6- and 12-week postoperative radiographs. No physical examination was performed. Results were graded similar to those of Clark et al., using a modification of criteria established by Bonney and MacNab (11), with 93% of patients achieving excellent or good results. None of the patients were classified as having a poor result, despite the fact that one patient had a nonunion that required revision arthrodesis. Catanzariti et al. published a retrospective analysis of the procedure in late 1999 (17). Planar resection was used to correct the interrnetatarsal angle and plantar translocation of the first metatarsal was used to prevent elevatus. Two-screw fixation was most commonly used, but occasionally one screw and a percutaneous Kirschner-wire was used. Thirty-nine patients with an average age of 43 years were evaluated an average of 75 months postoperatively (range 18-127 months). No formal subjective evaluation was performed, but the authors stated that 42 of 47 procedures (89%) healed uneventfully. The authors also related that all patients returned to preoperative activity at an average of 13 weeks postoperatively (excluding the five delayed and nonunions). No specifics were given regarding individual patient activities and functional demands. Objective evaluation included radiographic review of the interrnetatarsal angle and metatarsal protrusion distance. Previous analyses have used a variety of methods to evaluate outcome (9-14, 16). Although objective data have been reported, it has never been used for outcome assessment. More importantly, no study has correlated objective findings with patient subjective outcome. Thus,

factors that determine procedural success or failure have not been investigated. The purpose of this investigation is twofold: I) to provide a retrospective outcome analysis of the modified Lapidus procedure using strict subjective and objective criteria, and 2) to evaluate procedural outcome in three patient populations with differing functional demands: athletes, active patients, and sedentary patients. Materials and Methods Thirty-four patients (42 feet) had the modified Lapidus procedure performed by the senior author (R.T.B.) over a 7-year period (January 1990-December 1997). Effort was made to contact each patient for inclusion in the study. Six patients (seven feet) could not be reached and were lost to follow-up. An additional three patients (three feet) did not participate, each citing long driving distance as the reason. This left 25 patients (32 feet) for inclusion in the study, which represented 73.5% of patients and 76.2% of the operated feet. The study group included 23 females and 2 males with average age of 44.4 years (range 15-71 years) and average follow-up time of 39 months (range 13-91 months). All patients had symptomatic hallux abducto valgus with hypermobile first ray diagnosed by the senior author (R.T.B.; see diagnostic criteria in Table 1). Patients who underwent first MCJ arthrodesis for other reasons (e.g., degenerative arthritis) were excluded from the study. Hypermobility was defined as excessive motion of the first MCJ in the sagittal and transverse planes in conjunction with signs and symptoms of lesser metatarsal overload (Table I). A number of patients also demonstrated first MCJ instability as evidenced by excessive dorsal excursion at the first MCJ with the application of dorsal translational stress. Eleven of the 32 feet evaluated had the Lapidus procedure performed in isolation. The other 21 feet had additional surgical procedures performed as listed in Table 2. Follow-up involved subjective patient questionnaire, physical examination by the junior author (B.D.M.), and radiographic assessment. A clinical scoring system was designed to allow correlation of objective findings with patient subjective outcome. This scoring system allowed individual patient results to be compared to one another. Numerous sources delineating subjective and objective clinical parameters in the outcome assessment of hallux abducto valgus surgery were reviewed (9-14, 18). The authors have defined a set of subjective and objective criteria that are pertinent and complete in evaluating the modified Lapidus procedure (Tables 3 and 4). A detailed subjective patient questionnaire was developed using subjective criteria (Table 5). Patient responses

TABLE 1

The hypermobile first ray "symptom complex"

Subjective Lesser metatarsalgia Chronic recurrent lesser MTPJ capsulitis History of lesser metatarsal stress fracture Objective Physical Examination Excessive first MCJ range of motion First MCJ instability (+ dorsal drawer at 1st MCJ) Continued first MCJ motion with windlass mechanism activated Forefoot splaying with weightbearing Signs of lesser metatarsal overload Tyloma,IPK MTPJ capsulitis Stress reaction/fracture 2nd digit hammertoe with MTPJ extensus First MCJ dorsal exostosis Generalized ligamentous laxity Radiographic Lesser metatarsal hyperostosis (medial cortical thickening) Reducibility of 1M angle with "medial stress" maneuver MTPJ, metatarsophalangeal joint; MCJ, metatarsocuneiform joint; IPK, intractable plantar keratosis; 1M, intermetatarsal.

TABLE 2

Additional surgical procedures

Type of Procedure

Number of Procedures

PIPJ arthrodesis with FDL transfer 2nd metatarsal shortening osteotomy 5th metatarsal osteotomy Gastrocnemius recession Fibular sesamoidectomy Akin osteotomy Distal first metatarsal osteotomy Intermetatarsal neurectomy Lateral ankle stabilization

7

4 4 4 3 3 1

2 2

PIPJ, proximal interphalangeal joint; FDL, flexor digitorum longus.

allowed scoring of postoperative pain, function, and shoewear requirements. Each questionnaire was reviewed by the junior author (B.D.M.), at time of follow-up to assure understandable responses. Responses that were unclear to the examiner were clarified through discussion with each patient. Objective evaluation consisted of physical examination and radiographic assessment. These parameters were combined to give a score with a 100point scale. In order to compare procedural outcome between patient groups with differing functional demands, definitions were established for athletic, active, and sedentary patients. Assignment into one of these groups was based upon the response to question 1 of Table 5: 1. Athletic patients (N = 10): Patients who train for and compete in a specific sporting event. Both professional and amateur athletes are included. Amateur athletes range from recreational to elite/Olympic caliber. VOLUME 40, NUMBER 2, MARCH/APRIL2001

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TABLE 3

Subjective scoring system - 100 points

Category

Total Points

Pain - 40 points None Pain with athletic activities but not limiting, no pain with prolonged walking or ADl Consistent pain with athletics, occasional pain with prolonged walking, no pain with ADl Consistent pain with athletics and prolonged walking, no pain with ADl Consistent pain with athletics and prolonged walking, occasional pain with ADl Consistent pain with ADl Severe pain with ADL Function - 60 points Activity limitations - 30 points None No limitation of ADL, limitation of athletic activities, (i.e., decreased performance) No limitation of ADL, cannot participate in athletic activities Mild limitation of ADL Severe limitation of ADL Shoewear requirements - 20 points No restrictions Limited in dress & casual shoes, can wear athletic shoes Can only wear athletic shoes Cannot wear closed shoes Orthotic & accommodation requirements - 10 points Not needed Orthotic needed for reason other than forefoot problem (i.e., pronation) Orthotic needed for forefoot accommodation related to surgery

40

35 25 20 15

5

o 30 20 10

5

o 20 10

5

o 10 7

o

ADL, activities of daily living.

TABLE 4

Objective scoring system - 100 points

Category Physical Examination Hallux purchase - 15 points Hallux on ground, good strength with "paper test" Hallux on ground, weakness with "paper test" Hallux extensus, active purchase possible Hallux extensus, cannot actively purchase 1st metatarsal sagittal position - 10 points Parallel, or slight PF if this was desired because of shortening Plantarflexed starting position, can still DF above second metatarsal Elevated or severely plantarflexed (cannot DF above level of second metatarsal) Continued hypermobility - 10 points None Moderate Severe Sesamoiditis/lesser metatarsal overload - 10 points None Present with athletic activity only Constant or history of stress fracture Plantar callosities - 5 points None Mild - moderate diffuse callus IPK or very thick, diffuse callus

Total Points

15 10

5

o 10

5

o 10

5

o 10

5

o 5 3

o (continued)

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TABLE 4

(continued) Total Points

Category Radiographic Examination 1st MTPJ dorsiflexion - 15 points Excellent: greater than 60° Good: 46° _60° Fair: 31° _45° Poor: less than 30° Hallux abductus angle 10 points Excellent: 15° or less Good: 16°_20° Fair: 21° -25° Poor: >25° or hallux varus Intermetatarsal angle - 15 points Excellent: 0° _6° Good: 7°_8° Fair: gO_10°

15 10 5

o 10 5 2

o 15 10 5

o

Poor: > 10°, negative angle Tibial sesamoid position - 5 points Excellent: position 1 Good: position 2 Fair: position 3 Poor: position 4 or greater Metatarsal protrusion distance - 5 points Excellent: +/~ 2 mm Good: negative 3-4 mm Fair: negative 5-6 mm Poor: negative 7 mm or more

5 3 1

o 5 3 1

o

PF, plantarflexed; OF, dorsiflex; IPK, intractable plantar keratosis, MTPJ, metatarsophalangeal joint.

TABLE 5

Subjective patient questionnaire

1. What athletic activities were you involved in prior to your foot surgery? Please be specific with respect to frequency, duration, and intensity of activity. 2. Can you currently participate in these athletic activities at the same level you did prior to your foot surgery? If no, why not? What limits you? 3. Do you have pain in your foot with running activity (greater than 10 minutes)? If yes, please rate this on the following scale. Place a mark along the line at the area representative of your pain.

1- - - - - - - - - - - - - - - - - - - - - -10 No pain

Severe pain

4. Do you have pain in your foot with prolonged walking (20 minutes or longer)? If yes, please rate this on the following scale. Place a mark along the line at the area representative of your pain.

1- - - - - - - - - - - - - - - - - - - - - -10 No pain

Severe pain

5. Describe your everyday activities. Are you on your feet at work? How much and in what capacity? 6. Do you have pain in your foot with these everyday activities (excluding athletic activities)? If yes, please rate this on the following scale. Place a mark along the line at the area representative of your pain.

1- - - - - - - - - - - - - - - - - - - - - -10 No pain

Severe pain

(continued)

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TABLE 5

(continued)

7. Prior to surgery, which of the following shoe types could you wear? Dress Shoes Heels Pumps Flats

Casual Shoes

__

Athletic Shoes Prior to surgery what prevented you from wearing certain shoe types? 8. Which of the following shoe types can you wear now? Dress Shoes Heels Pumps Flats

Casual Shoes

__

Athletic Shoes What prevents you from wearing certain shoe types? 9. Do you wear any type of insert (orthotic) in your shoes? If yes, which type? Insole Heel lift "Over-the-counter" orthotic Custom orthotic Other (specify) If yes, are you able to go without the orthotic at any time? Have your orthotics needed special modifications since your surgery? 10. How would you rate the effectiveness of your surgery? Ineffective

Somewhat effective

Very effective

Completely effective

11. Did you have any problems after your surgery? If yes, please describe. 12. Are you satisfied with the appearance of your foot? If not, why? 13. Are you satisfied with the function of your foot? If not, why? 14. After your surgical experience, what reservations would you have about undergoing the same procedure? In other words, would you do it all over again? No reservations, would do it again Some reservations, would do it again Some reservations, would NOT do it again Major reservations, would do it again Major reservations, would NOT do it again 15. If you have reservations, what are they?

2. Active patients (N = 7): Patients who do not train for and compete in a specific sporting event, but whose activities of daily living are characterized by vigorous activity. These patients may be involved in occasional sporting activity, but not on a routine, consistent basis. 3. Sedentary patients (N = 8): Patients whose daily life is characterized by inactivity. These patients do not participate in sporting activity. Clinical Outcome Assessment Hallux Purchase

Patients were instructed to stand with normal angle and base of gait. A single piece of paper was placed beneath 76

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the hallux to determine if the hallux purchased the ground. If hallux purchase was present, an attempt was made to pull the paper from beneath the hallux to test strength. In cases of hallux extensus, patients were instructed to plantarflex the hallux to determine if active purchase was possible. First Metatarsal Sagittal Plane Position

Sagittal plane position of the first metatarsal with respect to the second metatarsal was assessed. Thumb and index finger of opposite hands were placed on the dorsal and plantar aspects of the first and second metatarsals at the metatarsophalangeal joint (MTPJ) level. The subtalar joint was placed in neutral and the midtarsal joint loaded

STARTING POSITION

"PARALLEL"

MAXIMAL DORSIFLEXION

MAXIMAL PLANTARFLEXION

0 00 00 00 00_ 0 0 0 0 0 0 00 J::J_Q-O 1st superior to 2nd

Level

"PLANTARFLEXED"

__0_0:_

"ELEVATED"

1st inferior to 2nd

__O_D_

1st inferior to 2nd

1st still inferior to 2nd

1st more inferior to 2nd

1st superior to 2nd

1st more superior to 2nd

1st cannot PF below2nd

FIGURE 1

First ray range-of-motion examination techn ique.

in a pronated position. The starring position of the first metatarsal was noted and cla ssified as superior, level, or inferi or to the second metatarsal. The first metatarsal was then placed throu gh maximum dorsiflexory and plantarflexo ry excursion (Fig. I). "Parallel" first and second metatarsals had a " level" starting position and equal dorsiflexory and plantarfiexory excursion. A "plantarflexed" first metatarsal had a starting po sition inferior to the second metatarsal and was unable to dorsiflex past the plantar aspect of the second metatarsal. An "e leva ted" first metatarsal had a starting position superior to the second metatarsal and was able to dor siflex to the dors al aspect of the seco nd metatarsal or higher (Fig. I). Continued Hypermobility

The medial column was placed through dorsifiexory exc ursion in an identical fashion to that de scribed in assessing first metatarsal sagittal position. Attenti on was given to the location where moti on occurred (navic ulocuneiform, talonavicul ar, intercuneiform joints). Patients without hypermobility had minimal medial column motion postoperatively. Patients with moderate hypermobil ity still

had fair amounts of medial column motion, most often located at the naviculocuneifonn articulation. Patients with severe hypermobility had medi al column excursion that mirrored that seen in patients considered for medial column stabilization procedures such as the Lapidus. In these patients , the Lapidu s procedure had failed to eliminate the majorit y of first ray motion . Plantar Callosities

Location and type of planta r callosities were evaluated and classified as diffuse or focal. Diffuse lesions were of varied thickness but involved area s at least 1 ern in diameter. Focal lesions were smaller than 1 em in diameter and con sisted entirely of intractable plantar keratoses (IPKs). Sesamoiditis/Lesser Metatarsal Overload

Edema or pain on palpation of the sesamoids or lesser MTPJ s was noted as was palp atory tenderness along lesser metatarsal diaphyses. Patient s were questioned if they experienced discomfort in any of these areas with acti vities of daily living (ADL) or athletic acti vity. VOLUME 40, NUMBER 2, MARCH/APRIL2001

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FIGURE 2

Dorsiflexory stress view used to quantify postoperat ive first MTPJ dorsiflexion.

Radiographic Assessment All radiographi c angular and position mea surement s were co nstructed and assessed by the same clini cian (B.D.M.) using the same gonio meter. Intermetatarsal and hallu x abductus angles, tibial sesa moid position , and metatarsal protrusion distance were measured according to techniques describ ed by Palladino ( 19). First MTPJ dorsiflexion was quantified radiographic ally as describ ed by Buell (20) (Fig. 2).

Statistical Analysis Statistical analysis wa s performed by a professional research statistician. Comparison s between two groups were made using a two- sampl e t test. Tests were done for equality of variances bet ween the two samples and the results used to determine whether to ass ume equal or unequ al variances in the two-sampl e t test. Comparisons between more than two gro ups were performed with analysis of variance (AN aYA). Th e results of these param etric tests were confirmed with nonp arametri c tests (Wilcoxo n two-sample test and Kru skal-Wallis test). Analysis of "return to activity" between the three acti vity level cla ssification s was made using the chi-square test. Comparisons with p values < .05 were considered significant.

Surgical Procedure The incisional approach is dorsom edial along the first ray, just medial to extensor hallucis longus (EHL) (Fig. 3). 78

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Careful attention is paid to the location of the medi al dorsal cutaneous nerve (MDCN) which usuall y crosses EHL pro xim al to the first MCJ , but occ as ionally traverses obliquely acro ss the joint (2 1). In cases where the nerve crosses the joint , it is sacri ficed proxim ally. Preservation of the nerve in this situation may lead to excessive tracti on and postoperative nerve entrapment. The first MTPJ is accessed through a dorsal line ar cap sulotomy. Medi al exostectomy and standard lateral soft-tissue release is perform ed. Additional corrective measures (i.e., medial capsulorrhaphy or extensor halluci s brevis tenotomy) are perform ed as needed. During first MTPJ dissection , articular surfaces of the first metatarsal and proximal phalanx are inspected. Chondral or osteochond ral lesions are treated if present. The proximal art icular set angle (PASA) is assessed and distal first metat arsal osteotomy for PAS A correction is performed as necessary. The first MCJ capsule is incised and an osteotome is used to "pry open" the joint to expose its entire depth . Failure to visualize and resect the plantar aspect of the joint can result in eleva tus positioning of the metatar sal. Thi s kidne y-be an shaped jo int is deep , vary ing from 2.6 to 3.2 cm (22) . In additi on , there is often a concave plantar lip on the first metatarsal base. If large, this is removed as it can interfere with position ing. Once the entire joint is visualized, articul ar cartil age is remo ved. Th is can be accomplished several ways . If the intermetatarsal (lM ) angle reduces completely on medial stress radio graphs (see "Discussion"), redu ction

FIGURE 3 Incision placement. Arrow indicates location of first MCJ and dotted line indicates typical course of MDCN.

can be accomplished without planar resection. In such cases, joint preparation is performed by curettage of cartilage to the subchondral bone level. Preservation of the subchondral plate is preferred since this has been shown to enhance screw purchase, improve stability, and minimize first metatarsal shortening (23). The subchondral plate is fenestrated with a 1.5 mm drill bit to promote cancellous bleeding and enhance arthrodesis. Use of a drill bit is preferred over a Kirschner wire for two reasons: most importantly, the drill bit cuts smoothly at low speed without generating heat which may cause osteonecrosis; second, small pieces of cancellous bone that accumulate in the drill flutes during drilling can be used as bone graft at the arthrodesis site. If inadequate reduction is obtained with medial stress, planar resection is needed. This is done by removing a laterally based transverse wedge from the metatarsal side of the joint. Reciprocal planing at the arthrodesis site is performed to increase congruity of opposing surfaces.

An anatomic irregularity that can prevent 1M angle reduction is a large lateral flare at the first metatarsal base. This flare can contact the second metatarsal prematurely and prevent 1M angle reduction. In addition, there is occasionally an articulation between the metatarsal bases. In both situations, the lateral flare of the first metatarsal can be excised to allow proper reduction. Once the first MCl has been prepared, the 1M angle is reduced and the arthrodesis site provisionally fixed with a Kirschner wire. Care is taken to position the metatarsal correctly in both transverse and sagittal planes. Intermetatarsal angle reduction is assessed by relative proximity of the first and second metatarsal heads which should be closely opposed. Adequate reduction is also assessed radiographically with an intraoperative radiograph with the foot loaded. If fluoroscopy is used, the surgeon should make sure the foot is loaded and positioned accurately. In addition to transverse plane first metatarsal positioning, sagittal plane positioning is evaluated. In most instances, the desired position of the first metatarsal is level with the second metatarsal head on clinical exam. The first metatarsal is intentionally translocated plantarly when the first ray is short, either preoperatively or as a result of joint preparation. Permanent fixation is accomplished with two 3.5mm cortical screws using lag technique. The screws are crossed in the sagittal plane, but not the transverse plane. Both screws are inserted 1.5-2 cm from the MCl to improve stability. Insertion of fixation in this manner provides resistance to cantilever bending at the arthrodesis site (23). Screw lengths of 36-45 mm are typical (Fig. 4,A and B). Once correction and fixation are acceptable, the wound is flushed and layered closure performed. Postoperative Management

Patients are kept nonweightbearing for at least 6 weeks and evaluated at 1, 2, 6, and 12 weeks postoperatively. First MTPl active and passive range-of-motion exercises are implemented at 2 weeks. Radiographs are taken at 6 weeks to evaluate the arthrodesis site. Of particular help in this assessment is the lateral oblique view, which allows excellent medial visualization of the joint and eliminates superimposition that occurs with other views. If union appears incomplete, patients are kept nonweightbearing and evaluated at 2-week intervals until arthrodesis is achieved. Following radiographic union, patients are allowed to walk in a protective, rocker-soled boot. The boot is used for 2-4 weeks or until patients are comfortable returning to shoes. Well-fitting athletic shoes that are cushioned and stable are recommended. VOLUME 40, NUMBER 2, MARCH/APRIL 2001

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FIGURE 4 A, AP view of two-screw fixation technique. Insertion point is 1.5-2 cm from joint. Distal screw is angled medially and plantarly. Proximal screw is angled plantarly, towards center of metatarsal shaft. B, Lateral view of two-screw fixation technique. Note sagittal plane angulation of screws.

By 12 weeks, patients are usually functioning well. Radiographs are taken to confirm healing. Gradual return to activities is allowed with goals based on individual patient activity level. Running and jumping are not recommended until at least 4 months postoperatively.

TABLE 6

Effectiveness rating vs. subjective score

Effectiveness Rating

N

Subjective Score

Completely

9 16

92.8 83.4 56.0 21.8

Very

Somewhat Ineffective

2

5

(S.D. 6.3) (S.D. 18.3) (S.D. 5.7) (S.D. 16.4)

Range

87-100 37 -100 52-60 10-50

Results

Subjective Evaluation

Nine patients (28%) rated their surgery "completely effective," 16 patients (50%) "very effective," two patients (6%) "somewhat effective," and five patients (16%) "ineffective." The five patients who rated surgery "ineffective" included two nonunions, two cases of 1M angle undercorrection, and one case of recurrence with intercuneiform diastasis. Overall, 78% of patients rated surgery "completely" or "very" effective. Comparison of effectiveness rating with subjective score is listed in Table 6. The average subjective score was 74.7 (SD = 28.5) with a range of 10-100. 80

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Seventy-eight percent of patients were satisfied with appearance and 75% were satisfied with function. Six patients (seven feet) were dissatisfied with appearance and eight patients (eight feet) were dissatisfied with function. The five patients who rated surgery ineffective were dissatisfied with both appearance and function. One patient (2 feet) was dissatisfied with her incisional scars. Other patients who were dissatisfied with appearance cited persistence of deformity (three cases of 1M angle undercorrection) and edema (two cases of nonunion) as reasons. The other three patients who were dissatisfied with function included one case of sesamoid pain, one patient with first MTPl degenerative arthritis that

developed postoperatively, and one case of sub-second metatarsal pain. Eighty-four percent of patients stated that they would have the surgery again. Forty-one percent of patients would do so without reservation, 30% with some reservations, and 13% with major reservations. All reservations involved prolonged time of immobilization and nonweightbearing. The five patients who would not have surgery again were the same patients who rated surgery ineffective. This group included two athletes, one active patient, and two sedentary patients.

with a range of 0°-19°. Comparison of effectiveness rating with 1M angle is listed in Tables 8 and 9. No differences in preoperative or postoperative 1M angles were seen among the three activity level groups. Statistically significant differences in subjective and objective scores were noted between the group whose 1M angle was reduced to 10° or less and those reduced to II ° or greater (subjective p = .018, objective p = .012). The highest subjective and objective scores were seen with 1M angle correction to 6° or below (Table 9). All patients with 1M angle 10° or less postoperatively stated that they would have the procedure performed again.

Objective Evaluation First MTPJ Dorsiflexion Comparison of effectiveness rating with objective scores of each parameter is listed in Table 7. The average objective score was 72.5 (SD = 19.3) with a range of 25-98. Intermetatarsal Angle The average preoperative 1M angle measured 16.7" and was corrected to (SD = 3.9°) with a range of 1 an average of 8.2° (SD = 3.4°) with a range of -2°-ISO. The average 1M angle reduction was 8.6 (SD = 4.9°) 0_27°

0

TABLE 7

Average postoperative first MTPI dorsiflexion measured 62.6° (SD = 19.9°) with a range of 20° -90°. Comparison of effectiveness rating with MTPl dorsiflexion is listed in Table 10. No differences in first MTPI dorsiflexion were noted among the three activity level classifications. StatisticalIy significant differences in subjective and objective scores were seen in patients with postoperative first MTPI dorsiflexion greater than 45° and those with dorsiflexion 4SO or less (p ::: .0001) (Table 10).

Effectiveness rating vs. objective results

Effectiveness Rating

N

Objective Score [Avg. (SO) Range]

1M Angle [Avg. (SO) Range]

1st MTPJ OF [Avg. (SO) Range]

MPO [Avg. (SO) Range]

Completely Very Somewhat Ineffective

9 16 2 5

86.3 73.4 67.5 46.8

7.0 (1.8) 5-10 7.3 (3.4) -2-13 8.5 (2.1) 7-10 12.8 (1.8) 11-15

73.7 63.1 50.0 46.0

-4.3 -3.2 -2.5 -1.2

(6.8) 76-98 (15.5) 45-91 (16.3) 56-79 (23.4) 25-76

(14.3) 48-90 (20.1) 28-90 (7.1) 45-55 (21) 20-70

(3.8) -10-3 (2.5) -7-2 (3.5) -5-0 (4.6) -8-4

1M, intermetatarsal; MTPJ, metatarsophalangeal joint; OF, dorsiflexion; MPO, metatarsal protrusion distance.

TABLE 8

Effectiveness rating

V5.

1M angle

Effectiveness

N

1M Angle-Pre [Avg. (SO) Range]

1M Angle-Post [Avg. (SO) Range]

1M Angle-Reduction [Avg. (SO) Range]

Completely Very Somewhat Ineffective

9 16 2 5

16.6 16.4 15.0 18.6

7.0 (1.8)5-10 7.3 (3.4) -2-13 8.5 (2.1) 7-10 12.8 (1.8) 11-15

9.6 9.1 6.5 5.8

(3.9) 12-24 (4.0) 10-24 (0.0) 15-15 (4.8) 15-27

(4.1) 5-16 (5.6) 2-19 (2.1) 5-8 (4.9) 0-13

1M, intermetatarsal.

TABLE 9

1M angle vs. subjective and objective score

1M Angle

N

6° or less 7° _8° 9° _10° 11° or more

9 10 7 6

SUbjective Score [Avg. (SO) Range] 87.6 80.3 84.3 34.8

(12.7) (21.1) (17.5) (35.1)

67-100 37-100 52-100 10-100

Objective Score [Avg. (SO) Range] 83.6 78.3 72.4 46.5

(14.6) (12.1) (11.6) (21.0)

48-98 54-91 56-88 25-76

1M, intermetatarsal.

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TABLE 10 1st MTPJ dorsiflexion vs. subjective and objective score 1st MTPJ OF

Greater than 60° 46° _60° 30° _45° Less than 30°

N

Subjective Score [Avg. (SO) Range]

80.2 (26.3) 12-100 7 81.1 (15.5) 60-100 6 51.8 (39.2) 10-100 2 73.5 (33.2) 50- 97

17

Objective Score [Avg. (SO) Range] 81.9 (11.3) 48- 98 80.3 (8.3) 67-90 45.0 (14.5) 25- 60 48.0 (18.4) 35-61

MTPJ, metatarsophalangeal joint; OF, dorsiflexion.

subjective effectiveness rating (Table 7). No differences in MPO were noted among the three activity level classifications. Age

Patients aged 30 years and younger had higher subjective and objective scores, but not at a statistically significant level (subjective p = . 19, objective p = .21) (Table 11). Activity Level

First Metatarsal Sagittal Plane Position

Since no standard method for quantifying first metatarsal sagittal plane position exists, the authors do not have objective data to report and corre late with subjective effectiveness. Using the described clinical examination techniqu e (Fig. 1), two feet had postoperative elevatus and three feet had postoperative plantarflexed first metatarsals. The remaining 27 feet had parallel first and second metatarsal position. Both patients with elevatus had sub-lesser metatarsal symptoms and hallux limitus (first MTPI dorsiflexion 33° and 35°). One of the patients rated surgery "very" effective and the other rated it "ineffective." Neither patient returned to their preoperative activity level. Two of the three patients with a plantarftexed first metatarsal had pain under the sesamoi d apparatus. One sym ptomatic patient rated surgery "very" effective and the other rated it "ineffective ." The asymptomatic patient rated surgery "very" effective. None of the three patients with plantarflexed first metatarsals returned to their preoperative activity level. Metatarsal Protrusion Distance

The average preoperative metatarsal protrusion distance (MPO) was 0.5 mm (SO = 3.4) with a range of - 8 to 6. Postoperatively this decreased to - 3.2 mm (SO = 3.3) with a range of -10 to + 4 (relative lengthening occurred due to concurrent second metatarsal shortening osteotomy in four cases). If the four cases with concurrent secon d metatarsal osteotomy are excluded, average shortening measure d 4.5 mm. Twenty-two feet had the joint prepared via curettage . Average shortening in this group measured 3.4 mm. Seven feet required planar resection to prepare the joint for arthrodesis. Average shortening in this group measured 7.5 mm. MPO did not corre late with patient

No significant differences in subjec tive or objective scores were noted among the three activity level classifications (one-factor ANa VA, subjective p = .80, objective p = .22, Table 12). However, only 30% of athletes returned to their preoperative activity level. Thi s was compared to an 86% "return to activity" in active patients and 75% return in sedentary patients. Of the seven athletes who did not return to preoperative activity level, four cited limitations involving the Lapidus proced ure. Two of these patients were limited by sesa moid pain, one by sub-lesser metatarsal pain, and one with continued pain over the medial first metatarsal head (due to undercorrection, 1M = 13°). The remainin g three athletes who did not return to preoperative activity level cited limitations involving areas other than the Lapidus site. Two of the patients related pain and stiffness in lesser digits secondary to hammertoe corrections involving arthrodesis of the pro ximal interphalangeal joi nt. The other patient was limited by degenerative arthritis of her knee. If "return to activity" is considered with respect to the Lapidus procedure only, difference s among the three activity group s are not statistically significant (p = .55). Of the three patien ts in the active and sedentary groups who did not return to preoperative activity levels, two were limited by nonuni on and the other by continued TABLE 11 Age vs. subjective and objective score Age

N

30 years or under 31-45 years 46- 55 years Over 55 years

6 9 9 8

Subjective Score [Avg. (SO)Range] 88.5 68.2 72.1 74.5

(15.2) (32.7) (27.0) (34.0)

60-100 12-100 15-100 10-100

Objective Score [Avg. (SO) Range] 81.5 79.2 62.8 69.3

TABLE 12 Activity level vs. clinical score and "return to activity" Activity Level

Athletic Active Sedentary

82

N (feet)

Subjective [Avg. (SO) Range)

Objective [Avg. (SO) Range)

Return to Activity

13 9 8

72.5 (26.3) 15-100 80.2 (27.8) 10-100 72.6 (34.0) 12-100

67.7 (21.8) 25-93 69.8 (20.5) 30-90 81.3 (12.0) 56-98

30% 3/10 86% 6/7 75% 6/8

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(11.4) (11.9) (24.4) (21.3)

60-91 56-93 25-88 30-98

sub-lesser metatarsal pain. The patient with sub-lesser metatarsal pain had parallel sagittal plane positioning of her first metatarsal and a normal metatarsal parabola but had severe fat pad atrophy at the level of the metatarsal heads as a probable cause. Although athletes did not "return to activity" as frequently as patients in the active and sedentary groups, 77% (10 of 13 feet) of athletes rated surgery "completely" or "very effective." This compares to 89% (8 of 9 feet) in active patients and 70% (7 of 10 feet) in sedentary patients. One athlete rated surgery "somewhat" effective because of sesamoid pain with impact loading activity. She had parallel sagittal plane positioning of her first metatarsal. Two athletes rate surgery "ineffective." One of these patients had a poor result due to undercorrection of the 1M angle (postoperative 1M = 13°) and had continued pain over the medial first metatarsal head. The other patient had excellent 1M angle correction (1M = 7°) but had deviation of the PASA that was not addressed. As a result, the sesamoid apparatus was not adequately reduced and recurrent hallux abductus occurred.

Hallux Varus Four feet had mild radiographic hallux varus; all four were asymptomatic and did not require revision surgery. Postoperative 1M angles for these patients measured -2°, 5°, 8°, and 8°. Two of the patients had fibular sesamoidectomy performed (secondary to degenerative arthritis) at the time of the modified Lapidus procedure. For the remaining 28 feet, the average postoperative hallux abductus angle measured 15.8° (SD = 8.3°) with a range of 5°-34°. Nonunion Five nonunions and two delayed unions occurred. Both delayed unions healed with use of electrical bone stimulation and protected weightbearing. Three of five nonunions were asymptomatic and were incidental radiographic findings at follow-up (Fig. 5). Two of these

Additional Objective Findings

Hallux Purchase Twenty-nine of 32 feet (91 %) had hallux purchase postoperatively. One of the patients without purchase had first metatarsal elevatus, and another had recurrence of hallux abductus related to divergence at the intercuneiform articulation. The third patient had no obvious cause for lack of hallux purchase. Sesamoid and Lesser Metatarsal Overload Eight patients (25%) had plantar callosities postoperatively. Six of these eight were symptomatic. Four of the six had symptoms severe enough to limit activity; two patients with lesser metatarsal overload symptoms had first metatarsal elevatus and two patients with sesamoid symptoms had a plantarftexed first metatarsal position. Eight patients with symptomatic lesser metatarsal callus preoperatively had complete resolution of both callus and pain postoperatively. Medial Column Hypermobility Six patients had medial column hypermobility postoperatively. Only one of these patients had lesser metatarsal plantar callus and this patient related no symptoms. In five of these cases, substantial motion was present at the naviculocuneiform articulation. The other patient had substantial motion at the medial- intermediate cuneiform articulation. All six of these patients rated surgery effective. Two of these patients had recurrent hallux abductus (HA angle 25° and 30° with postoperative 1M angle 8° and 10°, respectively). Both of these patients had metatarsus adductus deformity.

FIGURE 5 Asymptomatic fibrous nonunion. This patient played tennis without pain and had a normal physical examination. During initial follow-up radiographs revealed osseous union. Fixation was removed 1 year postoperatively. Nonunion was an incidental radiographic finding at follow-up. VOLUME 40, NUMBER 2, MARCH/APRIL 2001

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three asy mptomatic nonuni ons were partial in that only a porti on of the site was ununi ted. Patient interviews revealed no pain and no acti vity limitation related to the arthrodesis site. Physical examination was normal. Two nonunions were symptomatic and required revision arthrodesis. Both of these patients smoked cigarettes postoperatively and one bore weight prematurely (2 weeks postoperatively).

Lapidu s procedure with respect to patient numbers, dura tion of follow -up, and method s used for outcome assessment. One weakne ss of previous scoring system s is the combination of subjective and objecti ve findings in formulating clinical score s. The curre nt analysis is unique in several respects. It is the only analysi s that uses both subjective and objec tive criteria to evaluate procedure outcome (Table 13). In addition, it is the only study to correlate objecti ve results with subjective outcome . No pre vious study has examined specific reason s why the Lapidu s procedure succeeds or fails. The authors felt that separating subjective and objective findings would more accurately assess which factors contribute to procedural success or failure. Examination of Tables 14 and 15 compares subjective and objective variables exam ined in the current study and compares them to previous analyse s.

Discussion Study Design

The modified Lapidu s procedure certainl y has a place in the foot surgeons' armamentarium. However, long-term follow-up evaluating functional outcome has been lacking. Table 12 summarizes previous analy ses of the modified TAB LE 13

Literature revi ew summa ry

Author Correlation Butson Clark et al. Saffo et al. Sangeorzan Myerson Grace et al. Catanzariti et at, Mcinnes & Bouche

TABLE 14

% Follow-up

Duration (mont hs)

Subj . Eval.?

Obj. Eval.?

Subj.lObj .

78/119 20/32 44/54 32/40 53/67 23/30 39/47 34/42

Not reported 75% 34% 60% 96% Not reported Not reported 76%

(24-192) 24.3 (3-72) (12 - 60) (24-78) 28 (16-49) 61 (7-161) 75 (18-127) 39 (13 -91)

Yes Yes Yes Yes Yes Yes No Yes

Not reported Yes Yes Yes Yes Chart review Unclear Yes

No No No No No No No Yes

Postoperat ive subjective evaluation compariso n

Author

Pain

Butson Clark et al. Saffo et al. Sangeorzan Myerson Grace et al. Catanzariti et al. Mci nnes & Bouche

TABLE 15

Pts/ Feet

X X X X X X X

Function

ActiVity Level

Return to ActiVity

Shoes

Effectiveness

Appearance

Reservations

X

X X X

X X X

X

X X X X

X X

X

X

X

X

X

X

X

X X

X

X

Postoper at ive object ive evaluation compari son

Author

Purchase Sagittal Hypermobility Met Overload

Butson Clark et al. Satto et al. Sangeorzan Myerson Grace et al. Catanzariti et al. Mcin nes & Bouche

X X X

X

X X X

Plantar 1st MTPJ OF Tyloma X X X X

Xa

Xa 11.3°

31° 11° 0 13

65°

X

X X

X

X X

X X

1M TSP Shorteni ng Nonunion Angle

HA

0

62.6

0

15.8

Xa 4.3° 0 9 6° 0 5.8 0 5.4 0 2.1 0 8.2

6 mm 5 mm X

X

4.7 mm 4.5 mm

aValue measured but not reported . MTPJ, metatarsophalangeal joint ; OF, dorsiflexion ; HA, hallux abductus; 1M, intermetatarsal ; TSP, tibial sesamoid position .

84

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None None 12% 10% 9.5% 3.3% 10 .6 % 12.0%

The most unique aspect of the current study is "return to activity" analysis in three patient populations with differing functional demands. The decision to include this in the evaluation stemmed from the senior author's clinical impression that athletes seem to have a more difficult time returning to previous activity and performance levels after the Lapidus procedure than do nonathletes. The fact that only 30% of athletes returned to preoperative activity levels (compared to 86% and 75% in the active and sedentary populations) is concerning. It should be noted that three of seven athletes who did not return to preoperative activity levels cited reasons other than problems with the Lapidus site. Despite the fact that only 30% of athletes returned to their preoperative activity level, 77% rated their surgery as "completely" or "very" effective due to resolution of symptoms with activities of daily living. A limitation of the current analysis lies in the fact that "return to activity" in these specific groups has never been examined for any hallux valgus procedure. Perhaps similar findings would be present with distal or basilar osteotomies and may not be unique to the Lapidus procedure. Comparison of Results

statistically significant when compared to feet with angles of 7°_8° and 9°-10°. Previous studies have shown average postoperative 1M angles similar to the 8.2° average in the current study. These range from 2.1 ° for Catanzariti et al. (17) to 9° for Saffo et al. (12). Each of these studies (except Catanzariti's) reports a range of postoperative 1M angles including patients with angles above 10°. However, none of these studies evaluate outcome for patients with undercorrected 1M angles. All five patients in the current study with ineffective results had postoperative 1M angles greater than 10°. It stands to reason that some failures from previous studies were secondary to undercorrection. In addition, failure to recognize PASA deviation may result in incomplete reduction of hallux abductus despite adequate intermetatarsal angle correction. The current study also demonstrates improved subjective and objective scores as well as improved effectiveness rating with postoperative first MTPI dorsiflexion of at least 4SO (Tables 6 and 9). Average first MTPI dorsiflexion was 62.6° with a range from 20° to 90°. Despite the fact that first MTPJ dorsiflexion is an important factor for postoperative function, only two previous studies of the Lapidus procedure have reported values. Saffo et al. (12) reported average dorsiflexion of 31 postoperatively, while Myerson reported a value of 65° (14). Neither study reported how this measurement was taken and neither correlated first MTPJ dorsiflexion with outcome. One criticism of the Lapidus procedure is potential shortening of the first ray and alteration of the metatarsal parabola. Using the technique of subchondral plate preservation, first metatarsal shortening averaged 3.4 mm in the current series. In the small group of patients requiring planar resection for joint preparation (n = 7), shortening averaged 7.5 mm. Three previous studies have measured postoperative first metatarsal shortening. Saffo et al., who used biplanar resection to prepare the joint, reported an average 6 mm of shortening (12). Sangeorzan and Hansen, who preserved the subchondral plate during arthrodesis preparation, reported an average shortening of 5 mm (13). Catanzariti et al. used planar resection and reported an average shortening of 4.7 mm (17). In this review, postoperative metatarsal protrusion distance did not correlate with subjective score or effectiveness rating (Table 7). The authors feel that first metatarsal shortening, within reason, is well tolerated if careful attention is given to appropriate sagittal plane position. Another criticism of the Lapidus procedure is a high incidence of nonunion, ranging from 3.3% to 12% in previous studies (Table 15) (12-14, 16). The definition of nonunion is failure of osseous healing across the arthrodesis site. Thus, the definition includes asymptomatic fibrous unions in addition to atrophic, complete 0

Comparison of subjective results among studies is difficult due to differing criteria. The average subjective score in the current study was 74.7. Since no other study has used this scoring system, this number is important only because it allows correlation of subjective scores with specific objective variables and comparison between activity groups. It also provides a baseline comparison for future evaluation of other hallux valgus procedures. Comparison of patient subjective effectiveness rating with subjective score revealed higher scores in patients who rated their surgery "completely" or "very" effective (Table 6). This suggests that the subjective scoring system used adequately reflects patient subjective outcome. Patient subjective effectiveness rating is the closest measure by which the current study can be compared to previous studies. Seventy-eight percent of patients rated surgery as "completely" or "very" effective. Six percent felt it was "somewhat" effective and 16% rated it "ineffective." This closely parallels results published by previous authors. Table 15 summarizes clinical and radiographic objective variables examined in the current study and compares them to previous studies. Postoperative 1M angle and subjective score had significant correlation. Feet with 1M angles corrected to l O'or less achieved higher subjective and objective scores than did feet with postoperative 1M angles 11° or above. Feet with postoperative 1M angles 6° or below achieved the highest scores, but these were not

VOLUME 40, NUMBER 2, MARCH/APRIL 2001

85

r.

FIGURE 6 A, Preoperative AP view without medial stress. 1M angle = 1 B, Preoperative AP view with medial stress and 1M angle reduct ion to 8°. Note medial translation of first metatarsal compa red to A. Also note medial corti cal hypertrophy of the second metatarsal due to first ray hypermobility.

non unions. Th is study, as well as previous studies, have rep orted nonunion dat a according to the abo ve definition . However , incomplete union with pseudarthrosis is oftentimes an incident al radiograph ic findin g with patient s experi encing no symptoms and a normal physical exa mination (Fig. 5). The current study included five nonunions for a rate of 12%. Ho we ver , thr ee of the five cases were fibrou s nonuni ons that posed no fun ctional probl em s and were onl y discovered through fo llow- up radiographic ex amination. Two of the nonun ions were atro phic and required revision arthrodes is. Thus, the incid en ce o f symptomatic nonunion requ iring revi sion arthrodesis was 4.8%. Both patient s smo ked cigarettes (the only two smokers in the stud y), and one bore weight prematurely at 2 weeks postoperati vely. 86

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Studies ha ve demonstrated adverse effe cts of cigare tte smoking and nicotin e on bone healin g (24) . Anecdotally, the authors have observed this find ing with other osseo us proc edures and feel cautio n sho uld be exercised when co nside ring the Lapidu s procedure in patients who smoke cigarettes .

Patient Selection Th e primary indi cation for the modified Lapidus procedure is hallu x valgus with hyperm obile a nd/or unstable first Mel. Unfortunately, hypermobility has defied objec tive characteriza tion. Until objec tive parameters are clearl y defined , hypermobility is best understood as a "symptom co mplex" rather than a single objective entity. Thi s

symptom complex is a group of subjective and objective findings that define hypermobility (Table I). First MCl instability is an objective finding of increased dorsal translation with dorsal drawer stress at the first MCl. The writings of anatomist Dudley Morton on the "insufficient first metatarsal" best describe the symptom complex of hypermobility (25, 26). Morton described the insufficient first metatarsal as one that is short or exhibits excessive mobility in the sagittal and transverse planes. In such feet, the first ray is incapable of supporting load placed through the medial column of the foot. Ground reactive force excessively dorsiflexes the first ray and prevents normal mechanics at the first MTPl As the hallux attempts dorsiflexion during propulsion, subluxatory forces are placed through the first MTPl, causing hallux abductus and retrograde first metatarsal adductus. In addition to excessive sagittal mobility, the first ray also exhibits excessive transverse plane mobility, resulting in an increased 1M angle. Forefoot weightbearing load is altered when the first ray is excessively mobile. The first metatarsal fails to bear its share of forefoot load and instead the load is transferred to the lesser metatarsals. Patients with hypermobility will exhibit many, but not necessarily all, of the subjective and objective findings listed in Table 1.

Degenerative arthritis at the first MTPl in conjunction with a fused first MCl can pose problems (Fig. 7). The authors' evaluation of patients with arthrodesis of both joints has revealed a stiff medial column that does not function well. Caution should be used when considering the Lapidus procedure in patients with significant degenerative changes at the first MTPl In such cases, other options should be considered. Sesamoid pathology is another important preoperative consideration. Patients with preoperati ve sesamoiditis will have predictable worsening of this problem when the first metatarsal is stabilized in the sagittal plane. Several patients in the current study who did not have preoperative sesamoid symptoms developed sesamoiditis postoperatively. In all but a few cases, symptoms improved with time and the authors feel symptoms were due to stabilization of the first ray, which forced the sesamoid apparatus to increase its weightbearing load.

"Medial Stress" Maneuver This radiographic maneuver was described in Lapidus' early writings and evaluates first ray reducibility in the transverse plane. Lapidus performed this test by tightly bandaging the forefoot to squeeze the metatarsals together. The authors use a modified approach in which the hallux is manually distracted to relieve retrograde force at the first MTPl followed by manual medial stress applied to the first metatarsal head to correct the intermetatarsal angle (Fig. 6). This provides information regarding the fixed versus reducible nature of the deformity and helps determine whether planar resection is necessary. The use of planar resection has implications with respect to first metatarsal shortening and sagittal plane function.

Other Considerations Certain conditions exist in which the surgeon should exercise caution in choosing the Lapidus procedure. The two most notable circumstances include cigarette smoking and the inability of the patient to remain nonweightbearing for 6-8 weeks. The authors feel there are several other clinical situations in which caution should be exercised when considering the Lapidus procedure: first MTPl degenerative arthritis, sesamoid pathology, flexible anterior equinus foot type, and the professional or competitive athlete.

FIGURE 7 Grade IV degenerative arthritis of the first MTPJ in conjunction with an arthrodesed first MCJ.

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One foot type that deserves attention is flexible anterior equinus. In this situation. the surgical challenge lies in determining correct first metatarsal sagittal plane position. Fixing the first metatarsal "w here it sits" risks excessively plantarflexing the metat arsal. Moving the first met atarsal dorsally involves guesswork on the part of the surgeon in determining the most functional position and can be difficul t. If the proc edure must be used in this foot type, loading the foot on a flat surface intraoperatively to simulate weightbearing is recommended. In the authors' opinio n, arthrodes is in this position gives the most functional results. Patient activity level and functional demands should be co nsidered when contemplating the Lapidus procedure. The current data regar din g "return to activity" are of some concern. Only 3 of 10 athletes undergoing the procedure returned to preoperativ e athletic activity. Four of the seven athletes who did not return to activity cited problems with the procedure as causative. The authors' interpretation of these data is that athletes may not tolerate the increas ed stiffness that acco mpanies the pro cedure as well as patient s with less functional demands. Scientific substantiation of this interp retation would require larger patient numbers and eva luation of "return to acti vity" data in patients undergoin g other type s of hallu x valgus surgery. To date , this has not been do ne, but is an excellent direction for future research .

Surgical Technique Meticulou s surgica l techn ique and comprehensive postopera tive management are paramount to success with the Lapidu s procedure. Of primary importance is adequ ate 1M angle correction. Statistical analysis shows improved result s with 1M angle reduction to 10° or below. How ever, the authors recommend correction to 6° - 8°, as this appears to give the best resu lts. Postoperative first met atarsal sagittal plane position is also very important. Because this measurement is difficult to quantify, the authors do not have obj ective data to co rrelate with subjective outcome. Nonetheless, a primary goal of the procedure is the es tablishment of first ray weightbeari ng function. Th is is not acco mplished if the first metatarsal is art hrodes ed in an elevated position. Lesser metatarsal overload as well as first MTPl dysfunction ensues. Onl y two pati ent s in the curre nt study had postop erative first metatarsal ele vatus. Both patients had postoperative sub-lesser metatarsal pain and both had hallu x limitus. Arthrodesis in an excessively plantarflexed position ca n result in postoperati ve sesamoid complaints, especially if the proximal med ial column joints have little mobility. Three patients in the current study had plantarflexed first metatarsals postop eratively. Two of these pati ent s related persistent sesamoid 88

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complaints. Arthrodesis of the first metatarsal parallel or a few millimeters plant arflexed with resp ect to the seco nd metatarsal is recomm ended. If the first metat arsal is intentionally plantarfl exed , the surgeon should confirm that it ca n dorsiflex superior to the plantar aspect of the second metatarsal. Rigid internal fixatio n using lag technique is imp ortant for maint enan ce of correction as well as compression to facilitat e arthrodesis. Th e two-scre w technique described pro vides excellent stability. An important part of ac hieving stability at the arthrodesis site is adequate screw insertion distance fro m the joint. The authors' technique invol ves insertin g both screws 1.5-2 ern from the arthrodesis site. Thi s allows for use of screws 36 -45 mm in length. Use of long screws inserted in this fash ion provides very long lever arms to resist cantilever bending at the arthrodesis site (23) . Postoperative first MTPl dorsiflexion of 45 ° or gre ater was found to correl ate with improved subjective and objec tive scores as well as improved effe ctivene ss. Thi s finding likel y hold s true for all hallux valgus procedures, not ju st the Lapidu s procedure. First MTPl dorsiflexion ca n be optimize d by follow ing AO techn iques of atraurnatic dissection and ea rly postoperative mobil ization. Meticulous dissection technique and tissue handling aids in minimizing postoperative scarring and adhes ions. Startin g first MTPl passive range at postop erative wee k 2 is reco mmended. In additio n, first MTPl capsul ar adhesio ns may be minimi zed by using sma ll amounts of bone wax over areas of resected bleeding bone. Intra operative injection of short-ac ting phosphate steroid (e.g., dexameth asone pho sphate) may also be beneficial in decreasing postoperative edema and scarring.

Study Limitations One limitation of the current study is its retro spective nature. However, unlik e many retrospective studies, the curre nt study invol ved consecuti ve surgical proc edu res perform ed by a single surgeo n and evaluated independently by anoth er surgeo n. In addition, strict indications for the proc edure were used . It should be noted that both authors perform basilar and distal osteotomies on a regular basis. The primary indic ation for the Lapidu s procedure was hallu x valgus with first ray hyperrnobility and lesser metatarsal ove rloa d. Future pro specti ve investigations of the Lapidus procedure and othe r proc edures for hallux valgus corre ction are needed to delineate appropriate usage. Another limitation of the curre nt study is the use of a "point total" scoring system to eva luate and co mpare procedure outcome. Such scori ng systems reflect intrinsic bias regarding which clinic al factors are most import ant to successful outcomes. Nonetheless, scoring systems allow

outcome comparison in different patient populations and different procedures. Scoring systems are beneficial and allow improved, but not ideal, objectivity in analyzing results. The "return to activity" analysis has several limitations. Separation of patients into three activity groups requires larger numbers to reach statistically significant conclusions. The performance of additional surgical procedures concurrent with the modified Lapidus procedure complicates "return to activity" analysis. Several patients related problems with other procedures that caused limitation of activity. During patient interviews, care was taken to separate the effects of different procedures, but this was admittedly difficult. An ideal "return to activity" analysis would include larger patient volumes, performance of the modified Lapidus procedure in isolation, and absence of other confounding physical factors affecting activity. The measurement of medial column hypermobility and the location of this excessive motion are arguably subjective and dependent on the individual performing the physical examination. Although "hypermobility" has eluded objective definition, the authors included this parameter in order to assess whether the procedure had effectively eliminated what was considered to be excessive medial column motion. The assessment of hypermobility was made by one observer (B.D.M.) in all subjects and graded as none, moderate, or severe. When excessive medial column was present postoperatively, this was most commonly seen at the naviculocuneiform articulation. This was determined by the junior author (B.D.M.) using an examination technique in which the talonavicular (TN) joint was held stable while the medial column moved through range of motion. If motion was seen, it occurred at the naviculocuneiform (NC) joint since the TN joint was held stable and the MCJ was fused. In one case, visual exam of this motion seemed to be the result of instability between the medial and intermediate cuneiform rather than between the whole naviculocuneiform complex. Postoperative lateral weightbearing radiographs in patients with continued hypermobility at the NC articulation revealed faults at this location, confirming clinical exam. Conclusion The modified Lapidus procedure is an excellent technique for correcting hallux valgus with hypennobile first ray. The current study specifically examined which objective clinical parameters correlated with improved subjective outcome. Intermetatarsal angle reduction to 10° or less, first MTPJ dorsiflexion 45° or greater, and "parallel" first metatarsal sagittal plane positioning were shown to result in improved subjective outcome. Patient "return to activity" is an important consideration in any type

of surgery, especially for surgeons involved in treating athletes. In the current study, no significant differences in outcome were seen among athletes, active patients, and sedentary patients. Acknowledgments The authors would like to thank Ron G. Ray, DPM, and Jeffrey C. Christensen, DPM, for their assistance in developing the subjective and objective scoring systems and patient questionnaire. Special thanks to David Kerr at Axio Research Corp., Seattle, WA, for his assistance with statistical analysis. References I. Albrecht, G. H. The pathology and treatment of hallux valgus. Russ. Vrach. 10:14, 1911. 2. Lapidus, P. W. The operative correction of the metatarsus primus varus in hallux valgus. Surg. Gynecd. Obstet. 58: 183, 1934. 3. Kleinberg, S. Operative cure of hallux valgus and bunions. Am. J. Surg. 15:75, 1932. 4. Lapidus, P. W. A quarter century of experience with the operative correction of the metatarsus varus in hallux valgus. Bull. Hosp. Joint Dis. Orthop. Inst. 17:404, 1956. 5. Lapidus, P. W. The author's bunion operation from 1931 to 1959. Clin. Orthop. 16:119, 1960. 6. Truslow, W. Metatarsus primus varus or hallux valgus? J. Bone Joint Surg. 7:98, 1925. 7. Rutherford. R. Metatarsus primus varus reduction and stabilization via osseous grafting. J. Am. Coli. Foot Surg. 3:18,1964. 8. Rutherford, R. The Lapidus procedure for metatarsus primus adductus. J. Am. Podiatr. Assoc. 64:581, 1974. 9. Butson, A. R. A modification of the Lapidus operation for hallux valgus. J. Bone Joint Surg. 62:350, 1983. 10. Clark, M. R., Veith, R. G., Hansen, S. T. Adolescent bunion treated by modified Lapidus procedure. Bull. Hosp. Joint. Dis. 47: 109, 1987. II. Bonney, G., MacNab, I. Hallux valgus and hallux rigidus. J. Bone Joint Surg. 34-B:366, 1952. 12. Saffo, G., Wooster, M. F., Stevens, M., et al. First metatarsocuneiform arthrodesis: a five-year retrospective analysis. J. Foot Surg. 28:459, 1989. 13. Sangeorzan, B. J., Hansen, S. T. Modified Lapidus procedure for hallux valgus. Foot Ankle 9:262, 1989. 14. Myerson, M. Metatarso-cuneiforrn arthrodesis for management of hallux valgus and metatarsus primus varus. Foot Ankle 13:107, 1992. 15. Mauldin, D., Sanders, M., Whitmer, W. Correction of hallux valgus with metatarso-cuneiform arthrodesis. Foot Ankle I 1:59, 1990. 16. Grace, D., Delmonte R., Catanzariti A.R., Hofbauer M. Modified Lapidus procedure for adolescent hallux valgus. 1. Foot Ankle Surg. 38(1 ):8 - 13, 1999. 17. Catanzariti, A. R., Mendocino, R. W., Lee, M. S., Gallina, M. R. The Modified Lapidus arthrodesis: a retrospective analysis J. Foot Ankle Surg. 38(5):322-332, 1999. 18. Kitaoka, H. B., Alexander, I. J., Adelaar, R. S., et al. Clinical rating systems for the ankle-hindfoot, midfoot, hallux, and lesser toes. Foot Ankle 15:7, 1994.

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19. Palladino, S. 1. Preoperative evaluation of the bunion patient. In Textbook ofBunion Surgery, 2nd ed., pp. 1-79, edited by 1. Gerbert, Futura Publishing, Mount Kisco, NY, 1991. 20. Buell, T., Green, D. R., Risser, J. Measurement of the first metatarsophalangeal joint range of motion. 1. Am. Podiatr. Med. Assoc. 78(9):439-448, 1988. 21. Miller, R. A., Hartman, G. Origin and course of the dorsomedial cutaneous nerve to the great toe. Foot Ankle 17(10):620, 1996. 22. Mclnnes, B. D. Personal observation during surgical and cadaveric dissection.

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23. Ray, R. G., Ching, R. P., Christensen, 1. Hansen, S. T. Biomechanical analysis of the first metatarso-cuneiform arthrodesis. J. Foot Ankle Surg. 37(5):376-385, 1998. 24. Daftari, T. K., Whitesides, T. E., Heller, J. G. Nicotine on the revascularization of bone graft. Spine 19(8):904-911, 1994. 25. Morton, D. J. The Human Foot: Its Evolution, Physiology and Functional Disorders. Columbia University Press, Morningside Heights, NY, 1935. 26. Hansen, S. T. Hallux valgus surgery: Morton and Lapidus were right! Clin. Podiatr. Med. Surg. 13:3, 1996.