DEFINITION

Paul W. Lapidus originally described a procedure for the correction of hallux valgus in 1934.

This procedure was founded on the premise that hallux valgus was a secondary phenomenon to metatarsus primus varus arising from first tarsometatarsal (TMT) hypermobility and a medially oriented first TMT joint.

The original Lapidus procedure entailed excision of the lateral aspect of the medial cuneiform and first TMT arthrodesis coupled with a distal first metatarsophalangeal (MTP) capsulorrhaphy.

Many modifications of the original Lapidus procedure have been made, primarily advocating rigid internal fixation as a means for maintenance of reduction, lower nonunion rates, and earlier healing and mobilization.

 

 

ANATOMY

 

The goal of foot surgery is to obtain a plantigrade position with normal underlying mechanical alignment to allow for weight bearing, shock absorption, accommodation, and power for efficient painless gait.

 

Weight should be evenly distributed across the six weight-bearing surfaces, consisting of the paired sesamoids underlying the first metatarsal head, the lesser metatarsal heads, and the calcaneus.

 

The lateral column of the foot is designed for mobility to accommodate to uneven surfaces, whereas the medial column, including the first TMT joint, is more rigid to allow efficient power for push-off.

 

The first TMT joint is typically 30 mm in the dorsoplantar plane and half as wide in the mediolateral plane.

 

PATHOGENESIS

 

Equinus is often an underlying pathologic feature predisposing the midfoot to increased repetitive tension and subsequent longitudinal collapse and instability.

 

 

 

Debate exists with regard to whether first TMT hypermobility is a primary or secondary phenomenon. In particular, patients develop first TMT hypermobility potentially in both the axial and sagittal planes. Axial instability presents as metatarsus primus varus and resultant hallux valgus.

 

Sagittal instability presents as a dorsiflexed first metatarsal with predisposition to dorsolateral peritalar subluxation.

 

Furthermore, many patients have a medially oriented first TMT joint and tendency toward metatarsus primus varus.

 

NATURAL HISTORY

 

Symptomatic hallux valgus associated with metatarsus primus varus with underlying first TMT hypermobility

and equinus presents with progressive deformity and pain.

 

In the face of underlying pathologic first TMT hypermobility or equinus, the hallux valgus deformity will inevitably progress over time in both symptomatology and degree of deformity.

 

Consequently, it is imperative to treat any underlying pathology concomitantly with treatment of the hallux valgus deformity.

 

PATIENT HISTORY AND PHYSICAL FINDINGS

 

Physical examination methods include the following:

 

 

First TMT hypermobility: The examiner rests the index and middle finger of one hand over the dorsal aspect of the first TMT joint to monitor motion. The thumb of that hand rests under the lesser metatarsals. The other hand grasps the first metatarsal between the thumb and fingers and moves it up and down and side to side. Minimal motion should be palpated at this joint. Excessive motion or translation (>9 mm) is pathologic and indicative of first TMT hypermobility and instability. Occasionally, intercuneiform instability is noted.

 

Equinus/Silfverskiöld test: The examiner corrects the hindfoot to neutral subtalar position and checks dorsiflexion range of motion both with the knee in full extension and flexed greater than 25 degrees. An inability to obtain 5 degrees of dorsiflexion with the knee in straight extension that improves with flexion is indicative of isolated gastrocnemius equinus. An inability to obtain 10 degrees of dorsiflexion in both knee extension and flexion is indicative of soleus and gastrocnemius equinus.

 

First MTP range of motion: The examiner assesses flexion and extension of the first MTP and repeats the test with the first metatarsal held in a corrected position out of varus. Loss of significant range of motion in a corrected position is indicative of loss of congruency at the MTP joint. Consideration may be needed for additional distal metatarsal osteotomy.

 

Lesser metatarsalgia: With hypermobility of the first TMT joint, the first metatarsal is relatively elevated compared to the adjacent lesser metatarsals, resulting in pain and callosities. Callosities are seen beneath the lesser metatarsals, and the skin under the first metatarsal head is often soft from lack of weight bearing. Claw toes and extensor recruitment can result in distal migration of the plantar forefoot fat pad, exacerbating lesser metatarsalgia.

 

IMAGING AND OTHER DIAGNOSTIC STUDIES

 

Plain weight-bearing radiographs including anteroposterior (AP), lateral, and oblique views of the foot should be obtained. Every effort should be made to obtain a true lateral radiograph with talar dome overlap.

 

 

02

 

Features of first TMT hypermobility

 

 

 

Signs of second and third metatarsal overload (hypertrophied cortical thickening, stress fracture) Dorsal translation or dorsiflexion of first metatarsal

 

 

Plantar widening at the first TMT joint First to third TMT arthrosis

 

First MTP dorsal osteophytes

 

Occasionally, plain radiographs of the ankle are needed to rule out adjacent involvement.

 

Axial sesamoid view can be helpful to assess the extent of metatarsosesamoid arthrosis and degree of sesamoid subluxation.

 

Full-length hip-to-ankle radiographs are obtained if there is suspicion of an underlying lower extremity malalignment.

 

Seldom is a computed tomography (CT) scan, magnetic resonance imaging (MRI), or other imaging modality needed.

 

DIFFERENTIAL DIAGNOSIS

Hallux rigidus Metatarsosesamoid arthrosis Lesser metatarsalgia Interdigital neuroma

Gout or other inflammatory arthropathy

 

 

NONOPERATIVE MANAGEMENT

 

Many patients with hallux valgus and hypermobility of the first TMT joint are asymptomatic.

 

However, once symptoms develop, progression is inevitable, in particular in patients with underlying equinus contractures.

 

Initially, management can be directed at resolving local symptoms, including nonsteroidal anti-inflammatories, activity modification, rest, weight loss, shoe modifications, and orthotics.

 

In patients with equinus, a well-directed physiotherapy stretching protocol can be helpful.

 

SURGICAL MANAGEMENT

 

Indications

 

 

 

Hallux valgus with associated metatarsus primus varus and first TMT hypermobility Hallux valgus with first TMT arthrosis

 

 

Revision of failed hallux valgus surgery Contraindication

 

Open physeal growth plates

 

Preoperative Planning

 

AP foot plain radiographs are reviewed for the following:

 

 

 

Hallux valgus angle (HVA) (normal, <15 degrees) Intermetatarsal angle (IMA) (normal, <9 degrees)

 

 

 

Distal metatarsal articular angle (DMAA; normal, <10 degrees) Angle of first TMT joint (normal, <8 degrees medial angulation) Proximal phalangeal articular angle (normal, <10 degrees)

 

MTP joint congruity

 

Degree of sesamoid subluxation

 

Relative lengths of metatarsal heads (normal, cascade of gradual shortening from second to fifth metatarsal)

 

Lateral foot plain radiographs are reviewed for:

 

 

Talar first metatarsal angle (normal, 0 degree)

 

Based on the aforementioned, the surgeon formulates an operative plan, including the following:

 

 

Degree of correction

 

Need to excise lateral wedge from medial cuneiform

 

Need for concomitant second or third metatarsal shortening

 

Preoperatively, the surgeon assesses for equinus and the need for percutaneous Achilles tendon lengthening or gastrocnemius slide.

 

Goals of surgery include addressing the following:

 

 

 

 

Hallux valgus deformity Hypermobility of the first ray Metatarsus primus varus

 

 

 

Any pronation of first metatarsal or phalanges Hallux valgus interphalangeus (if present) Medial eminence

Positioning

 

The patient is placed supine on a radiolucent table with a padded wedge or bump under the ipsilateral hip to correct external rotation.

 

The arms are placed on arm boards and the ulnar nerve is padded.

 

A tourniquet is applied to the thigh, proximal enough to allow access to the proximal tibia for possible bone graft.

 

Once the limb is prepared and draped, a towel bump is placed beneath the knee to allow access to the

dorsum of the foot.

TECHNIQUES

• Exposure

Make an incision about 8 cm long between the extensor hallucis longus and brevis, roughly in line with the lateral aspect of the first metatarsal and medial cuneiform (TECH FIG 1).

Protect the deep peroneal nerve, dorsalis pedis artery, and dorsal cutaneous nerves.

Identify the first TMT joint by moving the first metatarsal, and reflect the capsule sharply off bone using the Henry angle of dissection.

 

 

 

 

TECH FIG 1 • A. Planned incisions. (continued)

 

 

03

 

 

 

TECH FIG 1 • (continued) B. Incision between extensor hallucis longus and extensor hallucis brevis.

• Correction of Metatarsus Primus Varus and Preparation of First Tarsometatarsal Joint

   

  Using a quarter-inch osteotome, remove the dorsal osteophytes over the first TMT joint and save them for bone graft.

   

  At this point, the joint is prepared in one of two ways:

   

  If there is a need to correct a medially angled first TMT joint, use an oscillating saw. First, insert an elevator to determine the slope of the joint. A depth gauge can be used to assess the depth of the joint. This distance can then be marked on the saw blade with a marking pen for safer and more accurate cuts. Resect a lateral wedge of bone from the medial cuneiform. Remove the piece and check it to ensure that adequate plantar bone was removed. Resect a minimal amount of bone from the first metatarsal base, again ensuring that enough plantar bone is removed. Avoid excessive metatarsal shortening.

   

  If there is no medially angled first TMT joint or if there is an excessively short first metatarsal, then prepare the joint using a series of curved osteotomes and curettes. Remove only articular cartilage and a small amount of subchondral bone to prevent shortening. This will give two congruent opposing surfaces for arthrodesis.

   

  Use an oblong curette to ensure there is no residual plantar lip resulting in excessive dorsiflexion. The first TMT joint is typically 28 to 30 mm deep.

   

   

  Drill each side of the joint with a 2.0-mm drill to improve blood flow to the arthrodesis site (TECH FIG 2). This should leave a lateral gap in the first TMT joint.

   

   

   

  TECH FIG 2 • Joint preparation.

• Distal Soft Tissue Procedure

   

  Extend the dorsal incision down to the first web space, taking care to avoid the digital nerves.

   

  Alternatively, make a second separate incision in the first web space.

   

  Deep to the attenuated intermetatarsal ligament is the fibular sesamoid and adductor hallucis tendon;

  leave it intact.

   

  Protect the fibular sesamoid, identify the first MTP capsule, and incise it longitudinally (TECH FIG 3).

   

  Make a separate medial incision over the first MTP joint, again watching for the crossing dorsal cutaneous nerves.

   

   

  Develop a flap superficial to the first MTP capsule, taking care to avoid thinning the capsule itself. Sharply incise the capsule full thickness longitudinally and reflect it plantar and dorsal.

   

  Tease back the capsular reflections to the first metatarsal head proximally to release the adhesions and allow the sesamoid to move independently.

   

  Grasp the plantar capsule with a Kocher. With gentle pressure, the metatarsal head should be easily reducible over the sesamoids while simultaneously correcting the IMA and closing the gap at the first TMT joint.

   

  Resect a minimal amount of medial eminence with a rongeur to allow shaping of the medial metatarsal head into a rounded surface.

   

   

   

  TECH FIG 3 • Distal soft tissue release.

   

   

  04

• Stabilization

   

  Before stabilization, hold the foot in a reduced position and palpate the forefoot to ensure it is plantigrade.

   

  Placing the foot on a flatfoot plate can assist in the assessment of forefoot and hindfoot position.

   

  Temporary Kirschner wire fixation may be helpful if assistance is unavailable.

   

  Burr a bone trough in the mid-dorsal aspect of the first metatarsal about 2 cm away from the joint and tapering out distally.

   

  Place a 4.0-mm screw after drilling in a lag screw fashion with a 4.0-mm and then a 2.9-mm drill (TECH FIG 4).

   

  Place a second 4.0-mm lag screw from the dorsal medial cuneiform to the plantar aspect of the first metatarsal base.

   

  In the past, this construct was further stabilized by placing a last 4.0-mm screw from the first metatarsal into the base of the second metatarsal, but this is now believed to be unnecessary.

   

  Alternative (and more robust) fixation methods include the use of dorsomedial or plantar locking plate fixation with or without lag screw fixation.

   

   

   

  TECH FIG 4 • Placement of a 4.0-mm screw after drilling in a lag screw fashion.

• Bone Grafting

   

  With improved surgical techniques and more robust fixation methods, the shear strain-relieving bone grafting is now not typically performed.

   

  If bone grafting is performed:

   

  Use a 5.0-mm burr to create two small troughs on the dorsomedial and dorsolateral aspects of the first TMT joint to serve as sites for shear strain-relieving bone graft (TECH FIG 5A,B).

   

  Also place bone graft in any gaps at the arthrodesis site.

   

   

   

  TECH FIG 5 • A. Bone graft trough. B. Shear strain-relieving bone graft. C. Final AP radiograph. D. Final lateral radiograph.

   

   

  Bone graft is obtained from the local procedure or lateral calcaneus bone graft.

   

  Obtain AP, lateral, and oblique plain film radiographs to ensure appropriate positioning and correction, which is often not seen in detail under C-arm fluoroscopy (TECH FIG 5C,D).

   

  05

• Wound Closure

   

   

  Plicate the medial first MTP capsule. Excessive capsule may be excised if redundant. It should not be necessary to overtighten the capsule to correct the hallux valgus.

   

  Close the remaining incisions in layers.

• Additional Procedures to Consider

   

   

  Gastrocnemius slide or percutaneous Achilles tendon lengthening Persistent equinus and forefoot overload

   

  Akin osteotomy

   

   

  Presence of associated hallux valgus interphalangeus Second or third metatarsal shortening

   

  Loss of metatarsal head parabola

   

  Particularly problematic in patients wearing high-heeled shoes

• Case Example (Courtesy of Mark E. Easley, MD)

Background and Imaging

 

A 75-year-old woman with recurrent/persistent hallux valgus after prior distal procedure

 

Symptoms included pain with activity, push-off during gait, and with shoe wear as well as tenderness over the medial eminence.

 

Minimal pain and no mechanical symptoms with hallux MTP joint range of motion

 

Radiographs revealed increased IMA and HVA (TECH FIG 6A), incongruent/asymmetric MTP joint, relatively narrow first metatarsal, and no obvious plantar gapping of the first TMT joint (TECH FIG 6B).

Exposure

 

A longitudinal dorsal incision is made over the lateral aspect of first TMT joint.

 

The superficial peroneal nerve branch to dorsomedial hallux and extensor hallucis longus and brevis is protected.

 

On medial aspect of first TMT joint, the tibialis anterior tendon is protected.

 

On lateral aspect of TMT joint, the deep neurovascular bundle is protected (TECH FIG 7).

 

 

 

TECH FIG 6 • A 75-year-old woman with recurrent/persistent hallux valgus deformity. A. AP view. Note relatively narrow first metatarsal. B. Lateral view. In this case, there was no plantar gapping of the first TMT joint to suggest hypermobility.

 

 

 

TECH FIG 7 • Intraoperative photo of the dorsal incision to the first TMT joint, identifying the deep neurovascular bundle after superficial peroneal nerve branch to dorsomedial hallux, extensor hallucis longus and brevis, and tibialis anterior tendon protected.

Tarsometatarsal Joint Preparation

 

Initial removal of lateral and plantar cartilage and bone to limit risk of first metatarsal dorsiflexion and correct IMA (TECH FIG 8A)

 

To limit dorsiflexion, the dorsal rim of cartilage is initially left intact as a reminder to maintain dorsal subchondral bone (TECH FIG 8B).

 

06

 

 

 

TECH FIG 8 • First TMT joint preparation. A. Initial removal of lateral and plantar cartilage and bone to limit risk of first metatarsal dorsiflexion and correct IMA. B. Dorsal rim of cartilage is initially left intact as a reminder to maintain dorsal subchondral bone. At conclusion of joint preparation, this rim of cartilage is removed. C. Curette in the first TMT joint being marked to demonstrate joint depth. D. Approximate 3 cm depth noted. E. The plantar most cartilage and bone must be removed or it may impinge and promote first metatarsal dorsiflexion. F. After cartilage removal, the subchondral bone must be penetrated to promote fusion.

 

 

The first TMT joint is deep, typically 3 cm. The plantar most cartilage and bone must be removed or it will impinge and promote first metatarsal dorsiflexion that could lead to lesser metatarsal head transfer metatarsalgia (TECH FIG 8C-E).

 

After cartilage removal, the subchondral bone must be penetrated to promote fusion (TECH FIG 8F).

Distal Soft Tissue Procedure

 

 

In this case, the dorsal longitudinal incision was extended to the first web space and second MTP joint. Through the dorsal incision, the lateral release of the suspensory ligament between the lateral capsule

and the lateral sesamoid is released to allow the metatarsal head to reduce over the sesamoids.

 

Through a medial midaxial incision over the first MTP joint, the medial capsulotomy is performed. In this revision surgery, there was a medial capsular defect that was repaired at the conclusion of the surgery to reconstitute the medial capsule (TECH FIG 9).

 

 

 

TECH FIG 9 • In this revision surgery, a medial capsular defect was identified. To reconstitute the medial capsule, this defect was repaired at the conclusion of the surgery.

 

 

07

 

 

 

TECH FIG 10 • Provisional first TMT joint fixation. A. With the first surgeon holding the reduction, the second places the provisional pins to maintain the reduction. B. Intraoperative AP fluoroscopy to confirm satisfactory correction of the IMA. C. Intraoperative lateral fluoroscopy demonstrating the first metatarsal dorsiflexion was avoided.

 

A medial eminence resection was not necessary because it had been performed as part of the index procedure.

Tarsometatarsal Joint Reduction

 

With the first surgeon holding the reduction, the second places the provisional pins to maintain the reduction (TECH FIG 10A).

 

Intraoperative fluoroscopy to confirm satisfactory correction of the IMA and that first metatarsal dorsiflexion has been avoided (TECH FIG 10B,C).

 

 

 

TECH FIG 11 • A. Distal guide pin, a compression screw, is placed while the reduction is maintained. B. In place of the more medial distal to proximal guide pin, a second compression is placed. C. Intraoperative fluoroscopy to confirm that IMA correction has been maintained.

Fixation

 

In place of the more lateral proximal to distal guide pin, a compression screw is placed while the reduction is maintained.

 

In place of the more medial distal to proximal guide pin, a second compression is placed (TECH FIG 11A,B).

 

Intraoperative fluoroscopy is performed to confirm that IMA correction has been maintained (TECH FIG 11C).

 

Persistent dorsiflexed first metatarsal or

lesser metatarsalgia

• Failure to resect plantar aspect of the first TMT

joint

Nonunion

• Inadequate joint preparation or inadequate

fixation, lack of bone graft

Hallux varus

• Overcorrection of IMA

• Release of adductor hallucis tendon

PEARLS AND PITFALLS

 

 

 

08

POSTOPERATIVE CARE

 

 

 

A well-molded posterior plaster splint is applied postoperatively to accommodate postoperative swelling. Analgesia is best managed with a single-shot popliteal block supplemented with a saphenous nerve block. At 2 weeks, patients are transitioned into a removable boot.

 

The patient is mobilized on a knee scooter.

 

 

Progressive weight bearing is allowed between 6 and 12 weeks in a removable boot. The patient is weaned out of the removable boot into standard shoes at 12 weeks.

 

Recent literature suggests that early postoperative weight bearing on the heel does not affect union rates; however, further research is necessary to support this protocol.

 

 

 

 

FIG 1 • Follow-up weight-bearing radiographs of the patient in TECH FIGS 6, 7, 8, 9, 10, 11. A. AP view demonstrating satisfactory hallux metatarsal head on sesamoids and correction of HVA and IMA. Note supplemental Akin osteotomy to optimize correction. B. Lateral view demonstrating no dorsiflexion of first

metatarsal.

 

 

The postoperative care for the patient in the example case is as follows:

 

 

Bunion strapping for 6 to 8 weeks

 

Protected weight bearing in a short-leg cast for 4 to 6 weeks

 

Transition to boot at 4 to 6 weeks provided radiographs suggest satisfactory bridging trabeculation at arthrodesis site.

 

Advance to full weight bearing onto forefoot at 6 to 8 weeks provided radiographs suggest satisfactory bridging trabeculation at arthrodesis site (FIG 1).

 

 

OUTCOMES

With appropriate surgical indications, surgical technique, and patient compliance, the patient satisfaction rate is better than 90%.

Rate of nonunion is approximately 5%. Recurrence of hallux valgus is rare.

 

 

COMPLICATIONS

See the Pearls and Pitfalls section.

 

 

SUGGESTED READINGS

1. Bendnarz PA, Manoli A. Modifed Lapidus procedure for the treatment of hypermobile hallux valgus. Foot Ankle Int 2000;21:816-821.

    

    

2. Blitz MN, Lee T, Williams K, et al. Early weight bearing after modified Lapidus arthodesis: a multicenter review of 80 cases. J Foot Ankle Surg 2010;49:357-362.

    

    

3. Coetzee JC, Wickum D. The Lapidus procedure: a prospective cohort outcome. Foot Ankle Int 2004;25:526-531.

    

    

4. Coughlin MJ. Hallux valgus. Instr Course Lect 1997;46:357-391.

    

    

5. Coughlin MJ, Mann R, Saltzman C. Surgery of the Foot and Ankle, 8 ed. Philadelphia: Elsevier, 2007.

    

    

6. DeVries JG, Granata JD, Hyer CF. Fixation of first tarsometatarsal arthrodesis: a retrospective comparative cohort of two techniques. Foot Ankle Int 2011;32:158-162.

    

    

7. DiGiovanni CW, Kuo R, Tejwani N, et al. Isolated gastrocnemius tightness. J Bone Joint Surg Am 2002;84-A(6):962-970.

    

    

8. Hansen ST. Hallux valgus surgery: Morton and Lapidus were right. Clin Podiatr Med Surg 1996;13:347-354.

    

    

9. Kazzaz S, Singh D. Postoperative cast necessity after a Lapidus arthrodesis. Foot Ankle Int 2009;30:746-751.

    

    

10. Lapidus PW. The author's bunion operation from 1931 to 1959. Clin Orthop 1960;12:119-135.

     

     

11. Mann R. Disorders of the first metatarsophalangeal joint. J Am Acad Orthop Surg 1995;3:34-43.

     

     

12. Morton DJ. Evolution of the longitudinal arch of the human foot. J Bone Joint Surg Am 1924;22:56-90.

     

     

13. Morton DJ. The Human Foot: Its Evolution, Physiology and Functional Disorders. Morningside Heights, NY: Columbia University Press, 1935.

     

     

14. Patel S, Ford LA, Etcheverry J, et al. Modified Lapidus arthrodesis: rate of nonunion in 227 cases. J Foot Ankle Surg 2004;43:37-42.

     

     

15. Pedowitz W, Kovatis P. Flatfoot in the adult. J Am Acad Orthop Surg 1995;3:293-302.

     

     

16. Sangeorzan BJ, Hansen ST Jr. Modified Lapidus procedure for hallux valgus. Foot Ankle Int 1989;9:262-266.