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1

What is tolertail

TOLERTIAL" - at "T"oe "O"ff "L"eg "E"xternally "R"otates "T"alus "I"nverts "A"nd "L"ocks. John Ayres MD

2

How do you lock the foot?

Function of the transverse tarsal joint. When the heel is everted, the transverse tarsal joints are parallel and unlocked, allowing the foot to be supple and pronate and accommodate to the floor. When the heel is inverted (varus), the transverse tarsal joint is divergent and locked, allowing for a stable hindfoot/midfoot complex for toe-off.

3

review hindfoot/forefoot motion

The critical assessment is to determine the relationship of the forefoot to the hindfoot.

If the heel is in a neutral position (subtalar neutral), the forefoot should be parallel with the floor to meet the ground flush (plantigrade).

If the first ray is elevated, the forefoot is in varus position. If the first ray is flexed, the forefoot is in valgus position (see Fig. 6.3). This should not be confused with hindfoot varus or valgus.

Example: in a long-standing flatfoot deformity the heel is valgus and the forefoot has compensated by going into varus or supinating to keep the foot flat to the ground.

Once the heel has been corrected, the elevated first ray can be easily seen 

4

Review the gait cycle

One full gait cycle from heel strike to heel strike is termed a stride.

Each stride is composed of a stance phase (heel strike to toe-off; 62% of cycle) and a swing phase (toe-off to heel strike; 38% of cycle) (Fig. 6.10).

Walking is defined by a period of double-limb support in addition to there always being one foot in contact with the ground throughout the gait cycle.

Ground reaction forces are approximately 1.5 times body weight during walking and 3 to 4 times body weight during running.

This difference is due to the increased load after the float phase of running, in which there is no foot in contact with the ground.

As the speed of gait increases, the stance phase decreases.

Soft-tissue contributions to gait mechanics

Swing phase

Anterior tibialis—contracts concentrically

Loss of function results in footdrop and steppage gait.

Heel strike

Anterior tibialis—contracts eccentrically

Controls the rate at which foot strikes the ground. In patients with footdrop, the rapid strike of the foot can result in a loud “slap” during heel strike.

Hindfoot—locked/inverted at initial strike; passively everts during transition from heel strike to foot flat

Allows for energy absorption. Failure of hindfoot eversion in patients with cavovarus deformity increases forces to lateral foot, resulting in stress fractures (fifth metatarsal), callus formation, and ankle instability.

Foot flat

Gastrocnemius-soleus complex—eccentric contraction

Controls forward progression of body over the foot

Loss of function results in a calcaneus gait with heel pain

Hindfoot—unlocked/everted for ground accommodation

At terminal stance, the FDL tendon is most active

Toe-off

Gastrocnemius-soleus complex—concentric contraction

In addition, as foot progresses from heel strike to toe-off, the following changes allow foot to convert from a flexible shock absorber to a rigid propellant:

Plantar fascia, which attaches to plantar medial heel and runs the length of the arch to the bases of each proximal phalanx, is tightened as MTP joints extend. The longitudinal arch is accentuated.

This is called the windlass mechanism (Fig. 6.11).

Hindfoot supinates, with firing of the PTT.

Transverse tarsal joint locks and provides a rigid lever arm for toe-off.

Insufficiency of the PTT will limit the ability to lock the transverse tarsal joint.

5

Halgus Valgus Schemata

chematic representation of tendons around the first metatarsal head. (A) Normal articulation in a balanced state. (B) Relationship of the tendons in hallux valgus deformity. FHBL, Lateral head of the FHB; FHBM, medial head of the FHB.

6

What is the Halgus Valgus Angle?

Hallux valgus angle. Marks are placed in the middiaphyseal region of the proximal phalanx and the first metatarsal at equal distances from the medial and lateral cortices. The longitudinal axis of the proximal phalanx is determined by an axis drawn through points A and B, and the longitudinal axis of the first metatarsal is determined by a line drawn through points C and D. The hallux valgus angle is formed by the intersection of the diaphyseal axes of the first metatarsal (line CD) and the proximal phalanx (line AB).

7

What is the IMMA?

First–second intermetatarsal angle. Middiaphyseal reference points (X) are placed equidistant from the medial and lateral cortices of the first (C and D) and second (E and F) metatarsals in both the proximal and distal middiaphyseal region. The longitudinal axis is drawn for both the first metatarsal (line CD) and the second metatarsal (line EF). The first–second intermetatarsal angle is formed by the intersection of these two axes (lines CD and EF).

8

what is the halgus valgus IP angle?

Hallux valgus interphalangeal angle. On the proximal phalanx, reference points (X) are drawn at middiaphysis. On the distal phalanx reference points are placed at the distal tip of the phalanx and at the midpoint of the articular surface of the distal phalanx. A line is drawn to connect the reference points for the axes of each phalanx. Line A indicates the proximal phalanx axis. The intersection of the axis of the distal phalanx with the longitudinal axis of the proximal phalanx forms the hallux valgus interphalangeal angle.

9

review the plan for surgical fixation of Halgus Valgus

10

Schemes of surgical fixation for Halgus Valgus

Lateral and AP drawings delineating various surgical options for management of hallux valgus. It is important to note that a distal soft tissue release is performed in conjunction with all corrections. The exception to this is a hallux MTP joint fusion.

11

Halgus Valgus text miller Review

Hallux valgus is defined as lateral deviation of the great toe with medial deviation of first metatarsal.

Pathophysiology: likely multifactorial

Intrinsic factors such as genetic predisposition, ligamentous laxity, and predisposing anatomy (convex metatarsal head, pes planus) are contributory.

Extrinsic factors such as certain types of shoewear (narrow toe box, high heels) also play a role.

Pathoanatomy (Fig. 6.26)

Medial capsular attenuation

Proximal phalanx drifts laterally, leading to the following conditions:

Plantar-lateral migration of abductor hallucis (ABH); change in position causes the muscle to plantar flex and pronate the hallux.

The pronation of the hallux is amplified by the proximal phalangeal attachment of the adductor hallucis (ADH).

Stretching of the extensor hood of the extensor hallucis longus (EHL)

Lateral deviation of the EHL and flexor hallucis longus (FHL), causing a muscular imbalance and deforming force for valgus progression and pronation of the great toe (Fig. 6.27)

First metatarsal head moves medially off the sesamoids, increasing the intermetatarsal angle (IMA).

Secondary contracture of the lateral capsule, adductor hallucis, and lateral metatarsal-sesamoid and intermetatarsal ligaments

Radiographs

Multiple measurements can be obtained from standard radiographs that guide treatment options.

Hallux valgus angle (HVA): angle formed by line along first metatarsal shaft and line along shaft of proximal phalanx (Fig. 6.28)

Normal: less than 15 degrees

First–second IMA: angle formed by lines along first and second metatarsal shafts (Fig. 6.29)

Normal: less than 9 degrees

Hallux valgus interphalangeus (HVI) angle: angle formed by lines along shafts of the proximal phalanx and distal phalanx (Fig. 6.30)

Normal: less than 10 degrees

Associated with a congruent deformity

Distal metatarsal articular angle (DMAA): angle formed by line along articular surface of first metatarsal and line perpendicular to axis of first metatarsal (Fig. 6.31)

Normal: less than 10 degrees

Increased angle associated with a congruent deformity.

Congruency of first MTP joint must be determined (Fig. 6.32).

Congruency is determined by comparing the line connecting the medial and lateral edges of the first metatarsal head articular surface with the similar line for the proximal phalanx.

When these lines are parallel, the joint is congruent.

Increased DMAA

Distal redirectional osteotomy of the metatarsal head (medial closed-wedge osteotomy)

Increased HVI

Akin osteotomy—medial closed-wedge osteotomy of the phalanx

Both of these operations may be required in addition to an osteotomy of the metatarsal to correct the increased IMA. Performing these osteotomies does not exclude additional distal or proximal metatarsal correction.

When these lines are divergent, the joint is incongruent.

Patients may present with both an incongruent joint and increased DMAA or HVI in severe deformities.

Position of sesamoids should be noted; in more severe or chronic deformities, the sesamoids are frequently displaced laterally.

Presence of degenerative changes in first MTP joint and first TMT joint should be noted.

A stiff or arthritic MTP joint requires a first MTP arthrodesis.

Nonoperative treatment

Adjusting shoewear and increasing the size of the toe box may limit pain with pressure along the prominent dorsomedial eminence.

There is no role for “corrective” braces or splints.

Operative treatment

The best indication for operative intervention is pain that has not responded to adjustments in shoewear or activity. Surgical correction of a hallux valgus deformity is not a cosmetic procedure.

The appropriate surgical procedure is determined by the abnormal radiographic angular measurements in concordance with underlying clinical abnormalities.

The patient’s physical findings and associated pathology dictate the appropriate surgical procedure regardless of the angular measurements.

First MTP fusion required for following conditions; IMA will correct with realignment of first MTP; concomitant metatarsal osteotomy is notrequired (Fig. 6.33).

Rheumatoid arthritis (RA)

Osteoarthritis

Painful or stiff first MTP—deformity cannot be passively corrected

Spasticity

Stroke

Cerebral palsy

Lapidus (first TMT realignment arthrodesis) required for:

Ligamentous laxity

First TMT DJD

Procedures never appropriate in isolation (high recurrence rate)

Distal soft tissue release (modified McBride procedure)

Modification—retention of the lateral (fibular) sesamoid to avoid hallux varus

Medial eminence resection

Medial capsular imbrication

Isolated osteotomy without associated soft tissue correction

Algorithmic approach to identifying the appropriate surgical intervention is listed in Box 6.1

Box 6.1Algorithmic Approach to Surgical Correction of Hallux Valgus

IMA ≤13 degrees AND HVA ≤40 degrees

Distal metatarsal osteotomy (chevron)

IMA >13 degrees OR HVA >40 degrees

Proximal metatarsal osteotomy

Instability of the first TMT/joint laxity

Lapidus (fusion of first TMT joint)

Arthritis or spasticity

First MTP fusion

Increased DMMA

Distal metatarsal redirectional osteotomy in addition to metatarsal translational osteotomy

HVI

Akin osteotomy

All patients should undergo a soft tissue release with all associated osteotomies and first TMT arthrodesis (Lapidus procedure) (Fig. 6.34).

IMA 13 degrees or less and HVA 40 degrees or less

Distal metatarsal osteotomy (chevron)

Distal soft tissue release

Medial eminence resection and capsular repair

IMA greater than 13 degrees or HVA greater than 40 degrees

Proximal metatarsal osteotomy/scarf

Distal soft tissue release

Medial eminence resection and capsular repair

Instability of first TMT/joint hyperlaxity

Lapidus procedure (fusion of first TMT joint) (Fig. 6.35)

Soft tissue release

Medial eminence resection and capsular repair

Increased DMAA (>10 degrees)

Distal medial closed-wedge metatarsal osteotomy in addition to what is required by angular measurements (Fig. 6.36)

IMA 13 degrees or less and HVA 40 degrees or less

Distal biplanar closed-wedge metatarsal osteotomy

Translates and redirects the metatarsal head simultaneously.

IMA greater than 13 degrees or HVA greater than 40 degrees

Proximal metatarsal osteotomy and distal medial closed-wedge metatarsal osteotomy

Instability of first TMT/joint hyperlaxity

Lapidus procedure and distal medial closed-wedge metatarsal osteotomy

If there is arthritis or pain at the first TMT, consider a Lapidus procedure

Hallux valgus interphalangeus

Akin osteotomy

Can be done in isolation if no other deformity present

Commonly performed in addition to procedures required to correct HVA and IMA (Fig. 6.37)

Operative complications

Avascular necrosis (AVN)

Distal metatarsal osteotomy and lateral soft tissue release may be performed simultaneously without increased risk of AVN.

Intraoperative laser Doppler study demonstrated that medial capsulotomy primary is insult to metatarsal head blood flow.

Care must be taken with vascular pedicle dorsolaterally.

Recurrence

Can occur with any procedure—highly associated with:

Undercorrection of IMA

Isolated soft tissue reconstruction (modified McBride procedure)

Isolated resection of the medial eminence

Persistent lateral subluxation of the sesamoids

Dorsal malunion

Results in transfer metatarsalgia—highly associated with:

Lapidus procedure (first TMT fusion)

Often related to inadequate preparation of plantar joint (depth of first TMT is ≈30 mm)

Proximal crescentic osteotomy

Hallux varus—associated with:

Resection of the fibular sesamoid (original McBride procedure)

Overresection of the medial eminence

Excessive lateral release

Overcorrection of IMA

Nonunion

Highest risk associated with a Lapidus procedure

12

Anatomy and function of lesser toe deformities

Static stability of the lesser toes is provided by the congruency of the MTP and interphalangeal joints.

Plantar plate—plantar aponeurosis and capsule—provides a soft tissue block to metatarsal head depression and prevents hyperextension of the MTP joint.

Persistent hyperextension at MTP joint may lead to attenuation and weakening of plantar structures.

Dynamic stability is provided by the various tendons that insert on lesser toes (Fig. 6.41).

Extensor digitorum longus: primary extensor of MTP joint

Runs through a sling over dorsal surface of MTP joint before splitting into a central slip that inserts on the middle phalanx and two dorsolateral slips that reconverge to insert at the base of the distal phalanx.

Distal extensor effect of the EDL is neutralized when the proximal phalanx is dorsiflexed, as in hammer-toe or claw-toe deformity.

There is no EDL to the fifth digit.

Extensor digitorum brevis (EDB) extends PIP joints and inserts on lateral aspects of EDL tendons on all but the fifth toe.

Flexor digitorum longus: primary plantar flexor of distal interphalangeal (DIP) joints as it inserts on plantar aspects of distal phalanges; also weakly plantar flexes MTP joints.

Flexor digitorum brevis (FDB) splits at the level of the MTP joint and inserts on plantar lateral aspects of the middle phalanges. The FDB is the primary plantar flexor of the PIP joints.

Intrinsic muscles of the foot include the lumbricals, which originate from the FDL tendon and insert on the extensor sheath over the MTP joints, and four dorsal and three plantar interossei muscles, which insert on the medial aspects of the proximal phalanges.

These muscles act similarly to the intrinsic muscles of the hand, flexing the MTP joints and extending the PIP and DIP joints.

Pull of the intrinsics is plantar to the rotational axis of the MTP joints.

Plantar translation of the metatarsal head after a distal osteotomy of the metatarsal places the intrinsics dorsal to the axis of rotation of the MTP joint, creating the “floating toe.”

Extrinsic muscles (EDL and FDL) overpower intrinsic muscles in positioning the lesser toes in hammer- and claw-toe deformities, with the EDL driving MTP joint extension and the FDL driving PIP and DIP joint flexion.

EDL is also a weak antagonist to flexion at interphalangeal joints, and likewise, the FDL is a weak antagonist to extension at MTP joint.

There is no flexor (FDL/FDB) attachment to the proximal phalanges.

Dorsiflexion of the proximal phalanx at MTP joint neutralizes these weak antagonist effects and accentuates the developing deformity.

Lesser-toe deformities occur much more commonly in women (up to a 5:1 ratio); difference thought to be secondary to high-fashion shoewear that constricts the forefoot and maintains the MTP joints in hyperextension.

A hammer-toe deformity most commonly involves the second toe, because it is relatively longer than the other lesser toes. A short toe box causes the second toe to buckle and extend at the MTP joint.

Long-term positioning of the MTP joint in hyperextension will attenuate the static plantar structures, allowing depression of the metatarsal head, distal migration of the fat pad, and imbalance of the dynamic forces on the toe, as described earlier.

13

what are the surgical treatment options for lesser toe deformities?

14

Review Hammer toe deformity

The characteristic hammer-toe deformity is flexion of the PIP joint. With weight bearing, the MTP joint appears dorsiflexed; this should correct with elevation of the foot off the ground (Fig. 6.42).

Contracture of the FDL is responsible for the flexible hammer-toe deformity

The term complex hammer toe refers to concomitant dorsiflexion of the MTP joint that does not correct and is more appropriately termed (and treated as) a claw toe.

Treatment depends on the flexibility of the deformity (Table 6.3).


 

 

Flexible deformity

Nonoperative—protective padding, tall toe-box shoes, corrective hammer-toe splints are effective.

Operative—flexor tenotomy or flexor to extensor tendon transfer

Fixed deformity

Nonoperative—accommodative shoes and protective padding can minimize callus formation. A corrective splint should not be used (Fig. 6.43).

Operative—PIP arthroplasty (resection of distal neck and head of proximal phalanx) or PIP arthrodesis

15

Review Claw toe deformity

Characterized by flexion of the PIP and DIP joints in the setting of fixed hyperextension of the MTP joint (Fig. 6.44)

Clawing typically involves multiple toes and is often bilateral.

Results from dysfunction of the intrinsic musculature

Often a neurogenic etiology

Cavus deformity, neuromuscular diseases that affect the balance of the extrinsic and intrinsic musculature, inflammatory arthropathies that lead to attenuation of soft tissue structures and instability of the MTP joint, and trauma have all been implicated in the etiology of claw toes.

Claw toes are a noted complication of compartment syndrome involving the deep compartments of the foot.

Treatment depends on the flexibility of the deformity (see Table 6.3).

Flexible deformity

Nonoperative—shoe modification, padding over any prominent or painful callosities, and use of orthotics to offload and support a potentially painful, plantarly displaced metatarsal head

Operative

Flexor-to-extensor tendon transfer of the FDL alters the function of the FDL to function as an intrinsic and to maintain the correction (Fig. 6.45).

Often leads to stiffness of MTP joint

Lengthening of the EDL and EDB is typically required.

Fixed deformity

Nonoperative—shoe modification, padding over any prominent or painful callosities, and use of orthotics to offload and support a potentially painful, plantarly displaced metatarsal head

Operative

PIP arthroplasty or arthrodesis, along with MTP joint capsulotomy and extensor lengthening

Dislocated MTP joint requires use of a Weil or distal metatarsal shortening osteotomy to reduce the MTP joint (Fig. 6.46).

16

Review mallet toe deformity

A mallet toe consists of an isolated flexion deformity at the DIP joint (Fig. 6.47).

Treatment (see Table 6.3)

Nonoperative—similar methods to those used in treating hammer-toe and claw-toe deformities

Operative

Flexible deformity

Flexor tenotomy

Fixed deformity

DIP arthroplasty (excision of the distal neck and head of the middle phalanx) or DIP fusion

Extensor repair can be performed to minimize recurrence.

17

Review crossover toe deformity

Multiplanar instability of the second toe may cause the toe to lie dorsomedially relative to the hallux (Fig. 6.48).

Commonly referred to as a crossover second toe, this deformity:

Requires disruption of the plantar plate—KEY component

Requires attenuation of the lateral collateral ligament

May be iatrogenic—caused by steroid injection within the MTP joint, which results in plantar plate attenuation

Treatment

Nonoperative—toe taping and corrective splints can minimize the discomfort but will not permanently correct the deformity.

Operative

For complete tears of the plantar plate, plantar plate repair has been advocated, with promising results. Plantar plate repair typically requires a shortening osteotomy of the distal metatarsal to aid in visualization and tissue repair.

Flexor-to-extensor tendon transfer with release of the medial collateral ligament

EDB tendon transfer with rerouting plantar to the intermetatarsal ligament

Reserved for less severe deformities; leads to more mobility of MTP joint than a flexor-to-extensor transfer

Distal metatarsal osteotomy (Weil) required if severe subluxation or dislocation of the MTP joint

If there is skin break down at the PIP dorsally, surgical débridement (with obtaining of specimen cultures) and delay of definitive treatment must be considered

18

Plantar plate pathology

Mild subluxation of the MTP joint that manifests as pain and swelling without any deformity

Drawer test results in pain within the joint (Fig. 6.49).

Most sensitive physical examination test to evaluate for plantar plate injury

More commonly seen in athletes (runners, tennis)

If the diagnosis is in question, an MR arthrogram of the involved joint will identify any injuries to the plantar plate or collateral ligaments.

Treatment

Nonoperative

Toe taping and stabilizing lesser-toe orthotics/metatarsal pads

Steroid injections are contraindicated and may result in iatrogenic creation of a crossover-toe deformity.

Operative

MTP synovectomy with reconstruction of the MTP joint capsule for isolated synovitis

With severe instability or deformity, a flexor-to-extensor tendon transfer is traditionally performed to stabilize MTP joint.

For complete tears of the plantar plate, plantar plate repair has been advocated.

Especially in high-level athletes

19

Review Friedburg infarction

Osteochondrosis (avascular necrosis) of one of the lesser metatarsals, most commonly involving the second metatarsal

Patient has pain localized over the affected metatarsal head.

The second metatarsal is affected in over two-thirds of cases. The third metatarsal accounts for most of the remaining cases. The fourth is affected in less than 5% of cases. The first and fifth metatarsals are rarely affected.

Pain is worse with ambulation and activities, and relieved with rest.

Common radiographic findings in Freiberg disease include:

Resorption of the central metatarsal bone adjacent to the articular surface, with flattening of the metatarsal head (Fig. 6.50)

Osteochondral loose bodies

Joint space narrowing in late-stage disease, with associated osteophyte formation along with collapse of the articular surface (Fig. 6.51)

Nonoperative treatment

Common strategies consist of activity modification, shoewear modification (hard sole), orthotics (metatarsal bar), and a period of protected weight bearing.

Operative treatment

For early-stage disease, joint débridement should be considered.

All inflamed synovium, osteophytes, and loose bodies are débrided through a dorsal incision.

This procedure should be considered for patients with relatively good articular surface congruity and minimal metatarsal deformity.

Many studies have reported good results with dorsal closed-wedge metaphyseal osteotomy of the affected metatarsal (Fig. 6.52).

Performed in conjunction with a thorough débridement of inflamed synovium, abnormal cartilage, osteophytes, and necrotic bone

Serves to rotate the plantar aspect of the articular surface, which is typically well preserved, to a more superior position, where it then articulates with the phalanx

20

What is IPK?

Intractable plantar keratosis?

Plantar callus secondary to excess pressure from metatarsal head

Predisposing factors: fat pad atrophy, plantar-flexed first ray, equinus contracture, intrinsic minus toe contracture, and hypertrophy of the sesamoid

Two main types (Fig. 6.53):

Discrete form

Localized callus with a hyperkeratotic core, usually caused by prominence of fibular/lateral condyle of the lesser metatarsal head

Commonly associated with a prominent tibial sesamoid

Nonoperative treatment

Callus trimming and soft metatarsal pads

Total-contact orthosis or extended steel shank should be considered for patients with significant fat pad atrophy.

Operative treatment

Shaving of the plantar surface of the tibial sesamoid or fibular metatarsal condylectomy

In more advanced cases, complete excision of the tibial sesamoid should be considered.

In the patient with a plantar-flexed first ray, dorsiflexion osteotomy should be considered.

Diffuse form

Secondary to pressure phenomenon from the entire metatarsal head

Commonly associated with an elongated metatarsal, an excessively plantar-flexed metatarsal, or transfer lesion. If there is no first ray pathology, it is important to evaluate for the presence of a gastrocnemius contracture.

Nonoperative treatment—similar to the discrete form of IPK

Operative treatment

Correction of the underlying deformity is critical— revision of the first ray to restore weight bearing through the medial column is critical

Secondary shortening of the lesser metatarsals may be required if the first ray is excessively short; however, shortening should not be done without correction of first ray pathology.

Gastrocnemius recession as required by the physical examination findings

21

what is bunionette deformity?

Prominence over distal aspect of fifth metatarsal head

Causes pain over lateral or plantar aspect of MTP joint, particularly with compressive shoewear

Bunionette deformity in conjunction with ipsilateral hallux valgus and metatarsus primus varus is termed splayfoot.

Three distinct types have been described, based on the anatomic location of the deformity along the fifth metatarsal:

Type I deformity—distinguished by presence of an enlarged fifth metatarsal head (Fig. 6.54)

Type II deformity—demonstrates lateral bowing of fifth metatarsal diaphysis (Fig. 6.55)

Type III deformity—demonstrates an abnormally widened fourth–fifth metatarsal angle (normal <8 degrees) (Fig. 6.56)

Conservative treatment

Shoewear modification, strategic padding, and shaving of the symptomatic callus are usually effective.

With plantar callus or associated pes planus, a metatarsal pad or custom orthotic device should be considered.

Surgical treatment

Lateral metatarsal head condylectomy (type I deformity)

Distal fifth metatarsal osteotomy (i.e., chevron; type II deformity)

Oblique diaphyseal osteotomy (type III deformity)

Metatarsal head resection should be considered for salvage.

Proximal osteotomy should be avoided owing to the tenuous blood supply at the proximal metadiaphyseal junction of the fifth metatarsal.

22

review the anatomy of the seasamoids

Medial (tibial) and lateral (fibular) hallucal sesamoids are part of a strong sesamoid capsuloligamentous complex.

Enveloped within the two heads of the flexor hallucis brevis (FHB) tendon, separated by an intersesamoid ridge called the crista

Attached to proximal phalanx via the plantar plate

Suspended by the collateral ligaments of MTP joint, metatarsosesamoid ligaments, intersesamoid ligament, abductor hallucis tendon, and adductor hallucis tendon

Analogous to the patella, sesamoids provide a mechanism to increase the mechanical advantage of the pulley function of the intrinsics (FHB).

Protect the FHL and disperse the forces beneath the first metatarsal head

23

Review seasamoid deformity

Sesamoid disorders can include acute injury (fracture, dislocation, sprain/“turf toe”), sesamoiditis, stress fracture, arthrosis, AVN, and IPK.

Diagnosis

Chief complaint is pain under the first metatarsal head, especially with toe-off.

Physical examination—tenderness with direct palpation of the involved sesamoid, pain with first-MTP ROM

Radiographs—in addition to AP and lateral views, lateral oblique (fibular sesamoid) and medial oblique (tibial sesamoid) views isolate each bone, and axial view shows the articulation with the metatarsal head (Fig. 6.57).

Radiographs of contralateral side should be obtained to compare position of sesamoids relative to the base of the proximal phalanx.

Tibial sesamoid should be 10.4 mm from the base, and fibular sesamoid should be 13.4 mm from the base.

Should be within 3 mm of the spaces on the contralateral extremity

Mechanism of injury—forced dorsiflexion of the first MTP joint, repetitive loading

Turf toe—forced dorsiflexion with foot in equinus (and axial load) can result in avulsion of the plantar plate off the base of the phalanx and subsequent proximal migration of the sesamoids.

Hyper–plantar flexion of MTP joint with valgus force is a less common mechanism; seen in beach volleyball players.

Tibial sesamoid is more frequently involved in trauma but also more likely to be bipartite or multipartite.

Conservative treatment

Turf toe

Grade 1—capsular strain

Signs—normal ROM, weight bearing without difficulty, normal radiographs

Treatment—stiff insole, taping, with immediate return to play

Grade 2—partial capsular tear

Signs—painful ROM, limited weight bearing, normal radiographs

Treatment—no athletic activity for 2 weeks, stiff insole, return to play if painless 60-degree dorsiflexion present

Grade 3—complete tear of the plantar plate

Signs—severe pain with palpation, limited and painful ROM, abnormal radiographs (fracture, proximal sesamoid migration)

Treatment—superior results demonstrated with operative repair of the plantar plate over conservative care.

Traumatic hallux valgus that involves the medial capsule and medial sesamoid with acute deformity of the hallux is best treated with immediate surgical repair as opposed to late reconstruction.

Sesamoid fracture

Initial treatment with a fracture boot to limit the stress across the sesamoid

Transition to sesamoid relief pad (dancer’s pad) with gradual resumption of activity

Sesamoiditis

Treated with antiinflammatory medications, rest, ice, and activity, and then shoewear modification

Operative treatment

Symptomatic nonunion or cases that prove refractory to conservative care can be treated surgically with bone grafting or with partial or complete sesamoidectomy.

Results of sesamoidectomy are the most predictable.

Excision of the proximal or distal pole achieves the best results and should be performed if the fracture pattern allows.

Complications of medial and lateral sesamoidectomy are hallux valgus and varus, respectively.

Repairing the defect with capsule (or a slip of abductor hallucis for the tibial sesamoid) helps prevent this complication.

Cock-up deformity (or claw toe) will occur if both sesamoids are excised (Fig. 6.58).

Care should be taken to avoid injury to the FHL and loss of flexor function, especially in the high-performance athlete.

24

review pes planus

May be congenital (see Chapter 3, Pediatric Orthopaedics) or acquired (also called adult-acquired flatfoot deformity [AAFD])

Determining whether the deformity is flexible or fixed is important

Fixed or rigid deformity requires a triple arthrodesis.

Tarsal coalitions tend to cause rigid flatfoot deformities.

Present in adolescence or later

50% bilateral

1 in 100 people affected

Diagnostics: radiographs and CT scans

Treatment

Nonoperative: rests, walking boot, casts, injections

Operative: resection and interposition with muscle/fatty tissue if less than 50% of middle facet is involved; arthrodesis if more than 50%

Pathology

Most common cause of AAFD is PTTD.

PTT is the primary dynamic support for the arch.

PTT fires after the foot is flat to generate heel rise and lock the transverse tarsal joint for a rigid, stable foot during push-off (toe-off).

The tibia rotates externally and the transverse tarsal locks as the PTT fires during push-off.

Etiology of PTTD is multifactorial and includes:

Zone of hypovascularity 2–6 cm proximal to the PTT insertion on the navicular

Overload of the arch due to activity or obesity

Inflammatory disorders such as RA

The spring (calcaneonavicular) ligament is the primary static stabilizer of the TN joint.

Incompetence of the spring ligament is associated with increased flatfoot deformity.

Most commonly the superomedial band (70%)

Isolated acute rupture of the spring ligament has been reported to cause an acute deformity without PTTD.

Reconstruction of the spring ligament with allograft or autograft as an adjunct to standard flatfoot reconstruction has shown success in early series.

25

review PTT deficiency

Patients complain of medial ankle/foot pain early, progressive loss of arch, and lateral ankle pain late (subfibular impingement).

Physical examination

Standing examination demonstrates asymmetric hindfoot valgus, depressed arch, and an abducted forefoot.

Too-many-toes sign: when the foot is viewed posteriorly, it appears to have more than five toes (Fig. 6.86)

Pain or inability to perform single-limb heel rise indicates insufficient PTT.

Whether deformity is flexible (passively correctable to a plantigrade foot) or fixed (rigid deformity that is not passively correctable) must be determined

Lateral impaction syndrome or subfibular impingement with significant valgus of the heel, such that it abuts the fibula, may be present; abutment of the lateral process of the talus and the calcaneus can occur as well.

Radiographs (Fig. 6.87)

Pes planus indicated by negative lateral talar–first metatarsal angle (Meary angle)

Forefoot abduction indicated by TN uncoverage

26

Review the treatment stages of Pes Planus PTT disorder

Stage I—tenosynovitis without deformity

Nonoperative

Immobilization (cast or boot)

Orthotic after acute swelling and pain subside

Arch support with medial heel wedge

Operative

Synovectomy of PTT

Stage II—flexible deformity is the critical feature; PTT is degenerated and functionally incompetent.

Nonoperative

AFO in conjunction with physical therapy has demonstrated the highest success rate.

Use of a full-length orthotic with an arch support, medial heel wedge, and medial forefoot support (if supination/forefoot varus present) is used after acute pain has resolved.

A lace-up ankle brace may also be used.

Operative (if conservative measures fail after 6 months or more)

Correction of all stage II deformities includes a tendon transfer (FDL or FHL) into the navicular to reconstruct the PTT.

Presence of a gastrocnemius contracture should be assessed for and if present corrected with a gastrocnemius recession.

Although reconstruction of the spring ligament has been advocated, there are limited data to demonstrate its efficacy at this time.

Stage IIA—defined by hindfoot valgus without significant forefoot abduction (<40% uncovering of the talus)

Medial slide calcaneal osteotomy (Fig. 6.88)

To address signs of subfibular impingement

Stage IIB—defined by forefoot abduction (>40% uncovering of the talus) in addition to hindfoot valgus

Lateral column lengthening (Fig. 6.89)

To address hindfoot valgus and improve the longitudinal arch of the foot/medial column of the foot

Additional medial slide calcaneal osteotomy may be required.

Stage IIC—defined by fixed forefoot supination/varus (first ray is elevated after correction of the hindfoot to neutral) in addition to hindfoot valgus (Fig. 6.90). Forefoot abduction may also be present.

Stable medial column—navicular is colinear with first metatarsal.

Cotton osteotomy (dorsal open-wedge osteotomy of the cuneiform) to plantar flex the first ray, to correct forefoot varus

Unstable medial column—plantar sag at NC or first TMT joint

Medial column fusion (based on point of collapse)

Isolated first TMT fusion

Isolated NC fusion

Combined NC and TMT fusion (both joints are involved radiographically)

Hindfoot treatment based on talar uncovering

Less than 40%—medial slide calcaneal osteotomy

More than 40%—lateral column lengthening and possible medial slide calcaneal osteotomy if residual hindfoot valgus

Stage II surgical summary

FDL or FHL tendon transfer for all patients

Gastrocnemius recession if contracture present

Hindfoot valgus—medial slide calcaneal osteotomy

Forefoot abduction—lateral column lengthening

Forefoot supination

Stable medial column—Cotton osteotomy

Unstable medial column—first TMT arthrodesis

Stage III—defined by a fixed/rigid pes planovalgus deformity

Nonoperative

Accommodative rigid AFO or Arizona brace. No attempt should be made to correct the deformity—correction carries increased risk of pain and pressure points, leading to ulceration.

Operative

Triple arthrodesis

If subtalar arthrodesis (alone or as part of triple) has been malunited in valgus, with tenderness in the lateral subfibular region, arthrodesis takedown and revision arthrodesis may be required.

Severely abducted deformities may require an all-medial approach, to limit risk of wound healing issues with the sinus tarsi approach.

Some authors argue that the calcaneocuboid joint is challenging to see, but cadaveric studies have demonstrated the ability to see >90% of each joint from the medial approach alone.

Additional medial column stabilization is occasionally needed for severe deformities (Fig. 6.91).

TAL if equinus contracture present

Stage IV—defined by incompetence of the deltoid ligament; standing AP ankle radiograph demonstrates lateral talar tilt (valgus) or ankle arthritis.

If the ankle valgus is passively correctable with minimal degenerative changes, an attempt can be made at deltoid ligament reconstruction with hindfoot reconstruction.

Rigid deformity or progressive arthritis requires TTC arthrodesis (Fig. 6.92).

27

Review the Diagnosis of Pes Cavus deformity

Defined by a high-arched foot, often with associated heel varus (cavovarus)

Pathology

Neuromuscular

Unilateral—tethering of the spinal cord or spinal cord tumors must be ruled out.

Bilateral—most commonly Charcot-Marie-Tooth (see Section 11, Neurologic Disorders)

Idiopathic—usually subtle, bilateral

Traumatic—secondary to talus fracture malunion, compartment syndrome, crush injury

Diagnosis

Patients complain of painful calluses under the first metatarsal, fifth metatarsal, and medial heel.

There may be pain along the peroneal tendons as well.

These may need to be addressed as part of surgical intervention.

Secondary to the plantar-flexed first ray and varus hindfoot

Plantar flexion of the first ray is secondary to overpowering of the tibialis anterior by the peroneus longus.

Varus of the hindfoot is secondary to the overpull of the PTT.

On an adequate weight-bearing, lateral foot radiograph, visibility of the middle facet of the subtalar joint indicates varus hindfoot.

Often associated with lateral ankle ligament instability, peroneal tendon pathology

Coleman block test used to assess flexibility of the hindfoot (out of varus) when the first metatarsal plantar flexion (forefoot valgus) is eliminated.

Wooden block placed just lateral to the first ray; first metatarsal head then lies off the block, with remainder of block on the weight-bearing foot.

If the hindfoot passively corrects into valgus, the deformity is forefoot driven (due to plantar-flexed first ray).

28

Review the treatment for pes cavus

Dwyer closed-wedge osteotomy of calcaneus for varus heel. (A) Lateral skin incision is made inferior and parallel to peroneal tendons. (B) Wedge of bone is resected with its base laterally. (C) Wedge of bone is tapered medially. (D) Calcaneus is closed after bone has been removed, and varus deformity is corrected to slight valgus.

 

Forefoot driven treatment-often times need forefoot osteotomy

29

what is the non-operative treatment for pes cavus?

Cavus foot orthotic. Note the hollowed-out recess under the first metatarsal head, laterally based forefoot wedge, and lowered medial arch.

30

Review Morton's Neuroma

Compressive neuropathy of the interdigital nerve, most commonly in the third web space, followed by the second web space (Fig. 6.60)

The pathophysiology of this condition is still poorly understood.

Theories include compression/tension around the IM ligament, repetitive microtrauma, vascular changes, excessive bursal tissue, endoneural edema, and eventual perineural fibrosis.

Diagnosis

Patients frequently report pain and burning on the plantar aspect of the web space, with more than 60% of patients noting pain radiating into the toe distally. Numbness is reported by only 40% of patients.

Exacerbated by footwear with narrow toe boxes and high heels

Higher predilection in the female population

Likely related to shoewear, with forced plantar flexion of the metatarsal heads

Physical examination

Palpation between and just distal to the metatarsal heads elicits plantar tenderness.

Compressing the medial and lateral aspects of the forefoot while palpating the web space structures can provoke symptoms and occasionally a bursal “click” with associated pain (Mulder sign).

Metatarsalgia and MTP synovitis often manifest similarly and should be ruled out.

Radiographs

Plain films should be obtained to rule out bony masses or deformity.

MRI or ultrasound can be used to identify other pathologies but are not required for diagnosis.

Nonoperative treatment

Shoewear modification (avoiding high heels and narrow toe boxes) is the most important and effective intervention.

Metatarsal pads placed proximal to the focus of pain can prevent direct pressure and widen the intermetatarsal space during weight bearing, thereby indirectly decompressing the nerve.

Corticosteroid injections can have moderate effectiveness (≈50% of patients report positive response); repetitive injections can lead to hammer-toe deformity.

Alcohol sclerosing injections have not proved to be effective and are not recommended.

Operative treatment

Excision of neuroma

Dorsal approach most common

Transverse intermetatarsal ligament is incised and resected.

The common digital nerve and its branches are identified and the nerve is resected 2 to 3 cm proximal to the intermetatarsal ligament (proximal to the small plantar branches), allowing the proximal stump to retract (Fig. 6.61).

Minimizes formation of stump neuroma, the most common complication

Difficult visualization results in a 4% rate of failure to excise the neuroma.

Overall success rates approach 80%.

Neuroma often causes perineural fibrosis.

Plantar approach

Decreases the rate of missed neuroma excision

Does not require incision of the transverse intermetatarsal ligament

Associated with increased risk (5%) of painful plantar scar

Typically used for revision neuroma resection