DEFINITION

Subluxation or dislocation of the metatarsophalangeal (MTP) joints results in a disruption of the fibers of the plantar plate, which is the central structure of the MTP joint dislocation. The plate provides a cushion to the joint and weight-bearing forces.

The key point in deciding how to treat this pathology is to determine whether the pathology leads to abnormal pressure distribution in the forefoot.

 

 

ANATOMY

 

The proximal phalanx and the fibrocartilaginous plantar plate form an anatomic and functional unit at the MTP joint.

 

The plate is the major factor of dorsoplantar stability.

 

The plantar plate attaches to the proximal phalanx and the plantar fascia, but except for the two collateral ligaments, it is without substantial fibrous attachment to the metatarsal head.17

 

 

The extensor digitorum longus tendon extends to the proximal phalanx and the proximal interphalangeal joint. Antagonists of the extensor mechanism are the flexor tendons and the plantar plate.

 

The function of the interossei and lumbrical muscles is to hold the proximal phalanx in a neutral position.

 

PATHOGENESIS

 

High functional stresses of weight bearing and repetitive hyperextension of the MTP joint can lead to attenuation or rupture of the plantar plate, followed by subluxation or dislocation of the toe.

 

A hallux valgus deformity is often associated with a subluxated second MTP joint.6,11

 

The hallux pushes the second toe laterally, which may lead to instability and maybe to subluxation.

 

 

It may also result from an excessive length of the second or third metatarsal relative to the first metatarsal. The second MTP joint is then biomechanically more subject to the pressure of tight stockings or shoes.

 

Once the plantar plate is elongated and ruptured, the dorsal capsule and the extensor tendon become contracted, leading to a chronically dislocated MTP joint.17

 

The plantar plate significantly contributes to stabilize the sagittal plane of the lesser MTP joints.3

 

NATURAL HISTORY

 

Weil presented in 1992 in Europe a joint-preserving, intraarticular shortening osteotomy, and Barouk1 first published it in 1996.

 

Researchers from Europe have shown in anatomic, clinical, and radiologic studies the advantages of the Weil osteotomy compared to alternative procedures.10,17,18

 

A dorsal soft tissue release with pin fixation,4 silicone implants,5 metatarsal neck osteotomies without fixation (Helal osteotomy),9,15,16,19 and MTP joint excisional arthroplasties7 have been reported in the literature as surgical alternatives. However, a high rate of complications such as nonunions, malalignments, and transfer

lesions are associated with these alternative surgical procedures.16

 

PATIENT HISTORY AND PHYSICAL FINDINGS

 

Physical examination methods include the following:

 

 

Determining circulatory status is necessary to assess not only the feasibility of an individual procedure but also whether multiple procedures can be performed, if necessary.

 

Clinical examination of cutaneous sensory response may indicate a systemic disease such as diabetes.

 

The drawer test is used to evaluate the stability of all the MTP joints and the reducibility of lesser toe deformities in plantarflexion. How stable overall is the first ray?

 

Passive range of motion: Normal range of motion is 60 to 80 degrees full extension to 40 degrees full flexion; loss of flexion may be a result of the contracted extensor tendons or because the proximal phalanx lies dorsal to the second metatarsal head.

 

Each patient must be analyzed individually, with attention to a detailed history and a careful clinical examination. Ruling out differential diagnosis is mandatory.

 

History of painful forefeet over a long period of months or years

 

The pain usually occurs dorsally over the toe and on the plantar side of the metatarsal head.

 

Plantar keratosis: This callus is a circumscribed keratotic area under the metatarsal head that usually corresponds with the patient's complaints (FIG 1).

 

Hammer toe: A hammer toe deformity may lead to MTP joint subluxation, dislocation, or both. However, MTP joint subluxation and dislocation can also lead to a hammer toe deformity.

 

A simultaneous hallux valgus deformity may lead to dorsiflexion forces in the second MTP joint. The great toe may cross under the second toe (“crossover toe deformity”).

 

A prominent dorsal base of the proximal phalanx is easily palpated.

 

 

83

 

 

 

FIG 1 • Plantar aspect of the foot with a hyperkeratotic area under the second metatarsal head.

 

 

Tightness of extensor tendons: The toe cannot be plantarflexed due to pain and to shortening of the extensor muscle and interosseous dorsalis muscle.

 

Rarely, a third or fourth toe is subluxated.

 

IMAGING AND OTHER DIAGNOSTIC STUDIES

 

Dorsoplantar and lateral weight-bearing radiographs should be obtained to rule out fractures or associated injuries and degenerative arthritic changes.

 

All radiographs are examined for the length of the second and third toe relative to the first and the alignment (Maestro line).

 

Radiographs must be obtained for subluxation or dislocation to assess joint congruency of the lesser MTP joints (FIG 2).

 

A “gun barrel” sign may be seen on the anteroposterior (AP) radiograph. The diaphysis of the proximal phalanx projects as a round hole in the area of the distal condyle of the proximal phalanx.

 

The articular cartilage of the adjoining surfaces leaves a “clear space” of 2 to 3 mm. This clear space diminishes with progression of the hyperextension of the MTP joint.

 

 

 

FIG 2 • Severe subluxated second and third MTP joint with an associated hallux valgus deformity.

 

 

 

Avascular necrosis of a lesser metatarsal head with infraction (Freiberg infraction) may be seen. The hallux valgus angle and the intermetatarsal angle are measured.

 

Pedobarography is highly sensitive to peak pressures in the foot. It allows static and dynamic qualitative measurement of pedal pressures and load distribution for specific areas of the foot. Load imbalance may also be detected as well as insufficiency of the first ray.

 

DIFFERENTIAL DIAGNOSIS

Morton neuroma

Freiberg infraction (avascular necrosis of the metatarsal head) Rheumatoid arthritis

Nonspecific synovitis Metatarsal head fracture

 

NONOPERATIVE MANAGEMENT

 

Initial treatment options for metatarsalgia include shoe wear modifications, metatarsal pads, and custom-made orthoses.

 

 

Trimming of the callus mechanically Orthotics for the foot

 

Reduce forefoot pressure

 

 

Lower heel to reduce metatarsal head pressure (avoid high-heeled shoes). Carefully placed metatarsal pad proximal to painful metatarsal head.

 

If metatarsalgia is due to a ruptured volar plate (such as in rheumatoid arthritis), often a stiff, full-length insole that limits MTP hyperextension of the foot is useful.

 

However, conservative treatment in an already existing dislocation is of no benefit, and surgical intervention is indicated.13

SURGICAL MANAGEMENT

 

The Weil osteotomy is a joint-preserving, intra-articular shortening osteotomy and has been recommended for the treatment of metatarsalgia resulting from a dislocated or subluxated MTP joint.

 

The goal of the Weil osteotomy is first to alter load transmission through the forefoot by shifting the plantar fragment proximal to the area of the lesion, where thicker and more compliant soft tissue is still present, and second to resolve the hammer toe deformity or MTP subluxations that are increasing or resulting in metatarsalgia.

 

The flexor to extensor tendon transfer significantly stabilized the disrupted lesser MTP joints in both superior subluxation and in dorsiflexion. The flexor to extensor tendon transfer following a Weil osteotomy also

significantly stabilized the disrupted lesser MTP joints in both superior subluxation and in dorsiflexion.3 Surgeons using the Weil osteotomy for plantar plate deficient MTP joints may consider adding a flexor tendon transfer to the procedure despite that this technique is challenging. Nevertheless, more comparative clinical data is needed to support this additional technique.

 

The direct plantar plate repair combined with a Weil osteotomy and lateral soft tissue reefing can restore the

normal alignment of the MTP joint.14 More research and clinical results needs to be done on direct plantar plate repair.

 

 

84

 

 

 

FIG 3 • A,B. The surgeon grasps the base of the proximal phalanx and attempts to subluxate or dislocate the joint with a dorsally directed force.

 

Preoperative Planning

 

All radiographic images are reviewed for subluxation or dislocation, alignment of the metatarsal heads, hallux valgus deformity, degenerative changes of the joints, and claw toes.

 

If there is a hallux valgus deformity or a hypermobile first tarsometatarsal joint, this pathology should be corrected to achieve a satisfying result.

 

The length of shortening is measured on the plain radiographs. The second metatarsal should be even with or shorter than the first, and the third should be shorter than the second metatarsal.

 

 

During the preoperative physical examination, the surgeon must look for plantar keratotic disorders. The tightness of the extensor tendon is palpated.

 

A drawer test of the dislocated MTP joint should be included in the examination under anesthesia (FIG 3).

 

Positioning

 

The patient is positioned supine on the operating table.

 

The surgery is performed either under general anesthesia or using a regional ankle block supplemented with intravenous or oral sedation.

 

An Esmarch tourniquet may be used to obtain a bloodless field.

 

Approach

 

A 3-cm longitudinal incision is made dorsal over the metatarsal for a single osteotomy, over the web space for a double osteotomy, and over two metatarsals for a triple osteotomy.

 

A small amount of soft tissue dissection is done to identify the extensor tendons, which are lengthened in a Z fashion.

 

A transverse or longitudinal capsulotomy of the MTP joint is used to identify the junction of the head and neck.

 

TECHNIQUES

• Exposure of Metatarsal

 

 

Make a 3-cm longitudinal incision dorsal over the metatarsal for a single osteotomy (TECH FIG 1A,B) or over the web space for a double osteotomy.

 

Perform a small amount of soft tissue dissection to identify the extensor tendons and lengthen them in a Z fashion (TECH FIG 1C-E).

 

 

 

TECH FIG 1 • A,B. Dorsal skin incision. (continued)

 

 

Incise the joint capsule in a transverse fashion and release the collateral ligaments if necessary.

 

Expose the metatarsal head with two small Hohmann retractors. Maximally plantarflex the toe and expose the metatarsal head with the help of an elevator (TECH FIG 1F,G).

 

Take care not to strip the plantar soft tissue attachments to aid in stabilizing the osteotomy and maintain vascularity to the head.

 

85

 

 

 

TECH FIG 1 • (continued) C-E. Z-lengthening of the extensor digitorum longus tendon; the extensor digitorum brevis tendon is usually cut. F,G. Exposure of the metatarsal with two Hohmann retractors; the head is exposed using an elevator.

• Osteotomy and Bony Slice Extraction

   

  Use a 2-mm bony slice extractor to lift the plantar fragment because the axis of motion of the MTP joint has changed with plantarflexion of the metatarsal head.

   

  Expose the metatarsal head and mark the osteotomies (TECH FIG 2A).

   

  Use an oscillating saw to perform the osteotomy at the dorsal portion of the metatarsal head without finishing the second cortex totally to avoid a free-gliding plantar fragment (TECH FIG 2B).

   

   

  The second osteotomy through both cortices is 2 mm under the dorsal cut (TECH FIG 2C,D). The bony slice can now be easily removed (TECH FIG 2E,F).

   

  86

   

   

   

  TECH FIG 2 • A. Exposure of the metatarsal head and marking of the two osteotomy levels. B. Osteotomy at the dorsal aspect of the metatarsal head. C,D. Plantar osteotomy of the metatarsal head. E,F. Removal of the bony slice after the osteotomies.

• Fixation of the Mobile Fragment

   

  Grasp the plantar mobile fragment with a pointed reduction clamp and shift it proximally to achieve the requisite amount of shortening that was measured preoperatively on the dorsoplantar radiographs (TECH FIG 3A).

   

  The second metatarsal should be even with or shorter than the first, and the third should be shorter than the second metatarsal.

   

  The plane of the osteotomy should be as parallel to the ground surface as possible. Secure the osteotomy with a special 2-mm titanium “snap-off screw” (Wright Medical Technology, Inc., Arlington, TN) (TECH FIG 3B). Use a 12-mm length for the second metatarsal and 11 mm for the other metatarsals.

   

  Remove the resulting dorsal protuberance over the metatarsal head remnant with a rongeur or the edge of the saw blade (TECH FIG 3C,D).

   

  Repair the overlying Z-lengthened extensor tendon and suture the skin.

   

   

  87

   

   

   

   

  TECH FIG 3 • A. Positioning of the plantar fragment. B. Fixation of the Weil osteotomy with a snap-off screw (Wright Medical Technology). C,D. Modeling of the dorsal protuberance with a rongeur or the edge of the saw blade.

• Maceira Modification of the Weil Metatarsal Osteotomy (Courtesy of Mark E. Easley, MD)

 

The traditional Weil osteotomy often leaves a prominent rim of cortex immediately dorsal to the metatarsal head cartilage.

 

Even when the residual dorsal overhang of the traditional Weil metatarsal shortening osteotomy is resected, this rim of cartilage is present.

 

To eliminate this rim of cortex and create a more natural transition between the cartilage and dorsal metatarsal cortex, the Maceira modification may be considered.

 

A dorsal skin incision is used and a capsulotomy performed, as for the Weil osteotomy.

Osteotomy

 

Initial transverse osteotomy cut is made with the microsagittal saw blade similar to that for the Weil osteotomy (TECH FIG 4A).

 

This initial cut is not completed, so that control over the osteotomy is maintained.

 

A vertical cut is made, removing the amount of dorsal cartilage and bone that would traditionally overhang in the Weil osteotomy once the metatarsal head is translated proximally (TECH FIG 4B).

 

This leaves the rim of bone that would normally be see in the traditional Weil osteotomy after the overhanging distal cortex is removed (TECH FIG 4C).

 

Immediately plantar to this rim of cortex, a second transverse osteotomy is created to converge with the initial transverse osteotomy and completing the separation between the metatarsal head and shaft fragments (TECH FIG 4D).

 

With this second cut, a wedge of bone is removed not only from the remaining distal cortex but also from the distal to proximal aspect of the osteotomy, thereby elevating the metatarsal head slightly (TECH FIG 4E-G).

 

The metatarsal head is then shifted proximally and aligned with the distal end of the metatarsal.

Fixation

 

A screw dedicated for securing metatarsal shortening osteotomies may be used, as was used in this case.

 

Directing the screw slightly medially or laterally allows for a longitudinal Kirschner wire (K-wire) to be passed across the MTP joint, if necessary (TECH FIG 5A,B).

 

If no K-wire is needed, the screw can be directed more vertically.

 

If preoperatively medial or lateral deviation of the toe is being corrected, the metatarsal head may be shifted relative to the metatarsal shaft, as would be done for hallux valgus correction.

 

In this example case, the second toe deviated medially, so the metatarsal head was shifted slightly medially to promote more neutral second toe alignment (TECH FIG 5B,C).

 

 

88

 

 

 

TECH FIG 4 • A. Initial transverse second metatarsal osteotomy using a microsagittal saw. To maintain stability of the osteotomy, only two-thirds of the osteotomy is completed at this point. Note that this is an intra-articular osteotomy, including the dorsal 10% of the articular surface. B. Perform a vertical osteotomy of the dorsal distal edge of the proximal fragment, resecting the amount of bone equal to the desired shortening. C. A ledge remains at the distal proximal fragment. D. Remove the residual distal ledge of the proximal fragment with a second transverse osteotomy. E. The second transverse osteotomy converges with the first and completes the proximal aspect of the osteotomy. F,G. Removing the wedge of bone created by the two transverse osteotomies elevates the metatarsal head.

 

 

89

 

 

 

TECH FIG 5 • A. With the metatarsal head translated proximally to shorten the metatarsal, a congruent transition is created between the dorsal aspects of the two fragments for fixation. B. The screw is directed slightly medially and secured. By directing the screw away from vertical leaves the option to safely pass a longitudinal pin across the MTP joint into the metatarsal without interference from the screw. C. Given preoperative medial deviation of the second toe, the metatarsal head was translated medially to promote a more neutral second toe alignment.

 

 

PEARLS AND PITFALLS
	Collateral ▪ We do not routinely release the collateral ligaments when performing a Weil ligaments osteotomy. A substantial portion of the metatarsal head blood supply courses via delicate arteries in the collateral ligaments.     Orientation ▪ We dorsiflex the ankle and use the plantar heel as a guide to orient the saw blade of the saw in the sagittal plane and look at the whole forefoot to get the orientation in the blade transverse plane.     Wedge ▪ We excise a wedge within the osteotomy in lieu of creating a single cut. Elevation resection is not important regarding loading of the head, but elevating the head will maintain a favorable center of rotation for the head. In theory, this will keep the intrinsic flexor tendons plantar to the center of rotation, thereby reducing the risk for postoperative toe elevation (“floating toe”).

 

 

POSTOPERATIVE CARE

 

 

Dressings and a tight bandage are used to protect the suture and to prevent swelling. The patient's toes are taped in slight plantarflexion.

 

 

Weight bearing with a postoperative shoe is allowed after the first postoperative day (FIG 4A). Patients should wear the postoperative shoe for 6 weeks.

 

Postoperative imaging includes dorsoplantar and lateral radiographs (FIG 4B-D).

 

Passive motion (starting on the fifth postoperative day) of the MTP joint is indicated and necessary to prevent postoperative extension contracture.

 

If swelling occurs, foot elevation, cryotherapy, and elastic stockings may keep the swelling down.

 

 

OUTCOMES

Clinical results of the Weil osteotomy have been promising. Outcomes include a significant reduction of pain, a significant reduction in plantar callus formation, a low dislocation rate, and increased ambulatory capacity.

No malunion or pseudarthrosis was documented in the literature.

Bony and soft tissue modifications such as lengthening of the extensor tendon, 2-mm bony slice extraction, and insertion of a K-wire from the tip of the toe across the MTP joint and the osteotomy into the metatarsal, in a position of 5 degrees plantarflexion (in severely subluxated contracted cases), may prevent postoperative dorsiflexion contracture.

Boyer and DeOrio2 described good results of a single-pin fixation for a combined metatarsal neck osteotomy with

90

proximal interphalangeal joint resection arthroplasty and flexor digitorum longus transfer in severely dislocated MTP joints and severe hammer toe deformities.

 

FIG 4 • A. Postoperative shoe. B. Preoperative radiographs with hallux valgus deformity and subluxation of second and third MTP joint. C. Chevron osteotomy with pin fixation along with a Weil osteotomy on the second to fourth rays. D. Seven-year radiograph showing maintenance of corrected lesser MTP joints.

 

 

 

COMPLICATIONS

Reported complications in the literature are floating or stiff toes, a high rate of postoperative dorsiflexed contracture and transfer metatarsalgia in cases of excessive shortening with variable rates, and a limitation of the range of motion in the MTP joint.8,10

The transfer of the flexor digitorum brevis (FDB) tendon to the proximal interphalangeal joint might restore the windlass mechanism and decrease the incidence of floating toes. This was shown in a cadaveric

study.12 Clinical results in the future may support this interesting finding.

 

 

REFERENCES

1. Barouk LS. Weil's metatarsal osteotomy in the treatment of metatarsalgia [in German]. Orthopade 1996;25:338-344.

    

    

2. Boyer ML, DeOrio JK. Metatarsal neck osteotomy with proximal interphalangeal joint resection fixed with a single temporary pin. Foot Ankle Int 2004;25:144-148.

    

    

3. Chalayon O, Chertman C, Guss AD, et al. Role of plantar plate and surgical reconstruction techniques on static stability of lesser metatarsophalangeal joints: a biomechanical study. Foot Ankle Int 2013;34(10):1436-1442.

    

    

4. Coughlin MJ. Subluxation and dislocation of the second metatarsophalangeal joint. Orthop Clin North Am 1989;20:535-551.

    

    

5. Cracchiolo A III, Kitaoka HB, Leventen EO. Silicone implant arthroplasty for second metatarsophalangeal joint disorders with and without hallux valgus deformities. Foot Ankle 1988;9:10-18.

    

    

6. Davies MS, Saxby TS. Metatarsal neck osteotomy with rigid internal fixation for the treatment of lesser toe metatarsophalangeal joint pathology. Foot Ankle Int 1999;20:630-635.

    

    

7. DuVries HL. Dislocation of the toe. JAMA 1956;160:728.

    

    

8. Hart R, Janecek M, Bucek P. [The Weil osteotomy in metatarsalgia.] Z Orthop Ihre Grenzgeb 2003;141:590-594.

    

    

9. Helal B, Greiss M. Telescoping osteotomy for pressure metatarsalgia. J Bone Joint Surg Br 1984;66:213-217.

    

    

10. Hofstaetter SG, Hofstaetter JG, Petroutsas JA, et al. The Weil osteotomy: a seven-year follow-up. J Bone Joint Surg Br 2005;87(11):1507-1511.

     

     

11. Kitaoka HB, Patzer GL. Chevron osteotomy of lesser metatarsals for intractable plantar callosities. J Bone Joint Surg Br 1998;80:516-518.

     

     

12. Lee LC, Charlton TP, Thordarson DB. Flexor digitorum brevis transfer for floating toe prevention after Weil osteotomy: a cadaveric study. Foot Ankle Int 2013;34(12):1724-1728.

     

     

13. Mann RA. Metatarsalgia: common causes and conservative treatment. Postgrad Med 1984;75:150-163.

     

     

14. Nery C, Coughlin MJ, Baumfeld D, et al. Lesser metatarsophalangeal joint instability: prospective evaluation and repair of plantar plate and capsular insufficiency. Foot Ankle Int 2012;33(4):301-311.

     

     

15. Trnka HJ, Kabon B, Zettl R, et al. Helal metatarsal osteotomy for the treatment of metatarsalgia: a critical analysis of results. Orthopedics 1996;19:457-461.

     

     

16. Trnka HJ, Mühlbauer M, Zettl R, et al. Comparison of the results of the Weil and Helal osteotomies for the treatment of metatarsalgia secondary to dislocation of the lesser metatarsophalangeal joints. Foot Ankle Int 1999;20:72-79.

     

     

17. Trnka HJ, Nyska M, Parks BG, et al. Dorsiflexion contracture after the Weil osteotomy: results of cadaver study and three-dimensional analysis. Foot Ankle Int 2001;22:47-50.

     

     

18. Vandeputte G, Dereymaeker G, Steenwerckx A, et al. The Weil osteotomy of the lesser metatarsals: a clinical and pedobarographic follow-up study. Foot Ankle Int 2000;21:370-374.

     

     

19. Winson IG, Rawlinson J, Broughton NS. Treatment of metatarsalgia by sliding distal metatarsal osteotomy. Foot Ankle 1988;9:2-6.