DEFINITION

Multiple potentially disabling disorders affect the hallux interphalangeal joint (IPJ).

Symptomatic hallux IPJ arthritis and/or deformity may be effectively treated with hallux IPJ arthrodesis.

The goal of hallux IPJ arthrodesis is to relieve intra-articular pain, dorsal IPJ and distal toe pressure due to flexion contracture, and/or resultant sesamoid pain due to chronic hallux metatarsophalangeal (MTP) joint extension and IPJ flexion contracture.

 

 

ANATOMY

 

The hallux consists of two phalanges, proximal and distal.

 

The hallux IPJ is the articulation of the proximal phalangeal head and the distal phalangeal base. This simple and stable hinge joint allows for motion up to 11.9 degrees of active extension and 46 degrees of flexion.

 

The osteology of the proximal phalangeal head has been described as a large trochlear groove that is wider and more concave on the plantar side. The phalangeal head topography is congruently matched by the distal phalangeal base.

 

Static stability is primarily created by the collateral ligaments originating from the superolateral aspect of the phalangeal head and inserting into the dorsal tubercle of the distal phalanx and augmented by the circumferential joint capsule that includes the plantar flexor plate. Dynamic support arises from the extensor and flexor hallucis tendons that cross the joint.

 

PATHOGENESIS

 

Intra-articular fractures: Often, they are due to direct axial load/impact to the hallux. Treatment with rest and a period of immobilization may relieve symptoms in the acute setting for nondisplaced fractures. Patients with displaced intraarticular fractures may require open reduction and internal fixation versus IPJ arthrodesis.

Degenerative hallux IPJ arthritis is often attributed to trauma.

 

 

 

FIG 1 • A. Osteochondral lesion on the proximal phalanx prior to hallux IPJ arthrodesis. B. Cock-up toe deformity in patient with chronically insufficient sesamoid complex.

 

 

Osteochondritis dissecans (OCD): OCD of the hallux IPJ is rare compared to that of the knee or talus. Case series of athletes with IPJ osteochondral fragments have been published.

 

 

Débridement and temporary Kirschner wire (K-wire) fixation have produced short-term symptomatic improvement of symptoms; to our knowledge, no long-term data are available (FIG 1A).

 

Claw hallux deformity: Etiology comprises compartment syndrome of the foot, Charcot-Marie-Tooth disease, cerebral palsy, spina bifida, and other static or progressive neuromuscular diseases. The soft tissue imbalance produces hyperextension of the MTP joint and flexion of the hallux IPJ.

 

Cock-up toe deformity: develops from chronic untreated turf toe (plantar plate) injuries. Likewise, when both the medial and lateral sesamoid are excised with inadequate repair of the residual flexor mechanism, a cock-up toe deformity may develop (FIG 1B).

 

Inflammatory arthritis: In select cases, inflamed synovitis and progressive periarticular joint destruction of an inflammatory arthropathy may occur in the hallux IPJ.

 

PATIENT HISTORY AND PHYSICAL FINDINGS

 

Occasionally, the patient recalls a traumatic inciting event such as stubbing of the great toe. However, the patient typically presents with an activity-related ache or pain in the hallux IPJ.

 

 

Careful history should be directed to explore possible etiology of the pain or deformity. Physical examination

 

Patient may have an obvious deformity such as claw hallux, hyperextension, or hallux valgus interphalangeus. The clinician should examine the skin for associated soft tissue corns, plantar callosities, or even open ulcers in patients with severe deformities.

 

 

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Tenderness is typically present directly over the IPJ.

 

Patient usually experience discomfort with active and passive hallux IPJ range of motion.

 

IMAGING AND OTHER DIAGNOSTIC STUDIES

 

 

Standard weight-bearing plain radiographs should include anteroposterior (AP), lateral, and oblique views. A radiographic grading system for hallux IPJ arthritis is available for reference:

 

Grade I: no degenerative change

 

Grade II: mild degenerative changes, less than 1 mm chondrolysis

 

Grade III: moderate degenerative changes with 1 to 2 mm of chondrolysis

 

Grade IV: severe degenerative changes with joint space narrowing, periarticular cysts, and alignment deformity

 

Computed tomography (CT) scan shows more detailed internal bony architecture. It may be used to evaluate the periarticular cystic lesions as well as estimate the bone stock available for IPJ arthrodesis.

 

Thin cut magnetic resonance imaging (MRI) through the IPJ may be used as a screening test for osteochondral lesions.

 

DIFFERENTIAL DIAGNOSIS

 

 

 

Intra-articular fracture Hallux IPJ dislocation Inflammatory arthritis

 

 

Posttraumatic degenerative arthritis Hallux IPJ gout

 

 

Osteochondral lesion Loose bodies

 

Claw hallux

 

Hallux valgus interphalangeus

 

FIG 2 • Fixed claw toe deformities, including a clawed hallux in a 50-year-old man. A. Dorsal view. B. Medial view. C. AP radiograph. D. Lateral radiograph.

 

 

 

NONOPERATIVE MANAGEMENT

 

Activity modification

 

 

Stiff-soled shoe modification Morton extension

 

 

Wider toe box to the shoe Extra depth to the toe box

 

 

Nonsteroidal anti-inflammatory medications Corticosteroid injection

SURGICAL MANAGEMENT

 

Indications for hallux IPJ fusion include symptomatic individuals who have failed nonoperative management:

 

 

 

Posttraumatic degenerative IPJ arthritis Inflammatory IPJ arthritides

 

 

IPJ varus or valgus deformity associated with hallux IPJ arthritis Claw hallux

 

Cock-up toe deformity

 

Progressive neuromuscular diseases, typically leading to fixed hallux IPJ flexion contracture

Preoperative Planning

 

 

Active and passive range of motion to determine if deformity is fixed or flexible (FIG 2A,B) Evaluation of rotational deformity, particularly with hallux pronation

 

Three weight-bearing views of the foot; consideration may be given to cone-in detail views of the hallux (FIG 2C,D)

 

Rarely is more detailed imaging necessary. High-resolution MRI may reveal cartilage damage not visible on plain radiographs and CT may provide greater detail of subchondral bone irregularity.

 

 

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Positioning

 

This procedure is typically performed under a peripheral nerve block.

 

The patient is placed in a supine position with a support under the ipsilateral hip so that the toes of the affected foot are pointed toward the ceiling.

 

The tourniquet, if desired, may be used at the ankle or calf.

 

Approach

 

We prefer to use a dorsal approach to the hallux IPJ.

 

Although perhaps not universally used, we typically perform isolated hallux IPJ arthrodesis via an H-shaped

incision. In our experience, this incision allows for optimal exposure and heals reliably.

TECHNIQUES

• Incision

The H-shaped incision is made with the transverse incision at the IPJ and the dorsomedial and dorsolateral longitudinal limbs extending approximately 1 cm distally and proximally to the transverse incision (TECH FIG 1A).

Full-thickness skin flaps including capsule and periosteum are raised; undermining of the skin layers should be limited (TECH FIG 1B).

Dissection is carried down to the terminal portion of the extensor hallucis longus (EHL) tendon. A transverse tenotomy is performed. The EHL tendon may be tagged to be reattached at the completion of the arthrodesis to reinforce toe extension that otherwise would be limited to the extensor hallucis brevis.

With the full-thickness flaps elevated from the capsule distally and proximally, the IPJ is exposed along the path of the transverse joint line.

Collateral ligaments are then freed from their periarticular attachments, thereby exposing the IPJ.

 

 

 

 

TECH FIG 1 • A. Dorsal H-shaped incision. B. Capsular and subperiosteal elevation distal and proximal to the IPJ.

• Preparation of the Hallux Interphalangeal Joint

   

  Using retraction on the deeper tissues to reflect the distal and proximal flaps, the distal articular surface of the proximal phalanx is exposed.

   

  With the soft tissues protected, we use a microsagittal to remove the residual articular surfaces. We minimize bone resection by initiating the saw cut immediately proximal to the articular surface.

   

  We prepare the arthrodesis of the hallux IPJ in slight plantarflexion by tilting the saw to remove slightly more bone from the plantar aspect than the dorsal aspect of the proximal phalanx at the IPJ (TECH FIG 2A,B).

   

  Avoid overpenetration of the saw blade, as it may damage the flexor hallucis longus (FHL) tendon immediately plantar to the IPJ.

   

   

   

  TECH FIG 2 • A,B. Proximal phalanx preparation. A. The bone is cut immediately proximal to the articular surface. B. The cut is made in slight plantarflexion (more bone resected dorsally than plantarly).

  (continued)

   

   

  The articular surface of the proximal aspect of the distal phalanx is prepared using a microsagittal saw and also with the cut made in slight plantarflexion (removing slightly more bone plantarly than dorsally) (TECH FIG 2C,D).

   

  Avoid overpenetration of the saw blade, as it may damage the FHL tendon immediately plantar to the IPJ.

   

  Clinically and fluoroscopically, proper hallux alignment after bony preparation is confirmed (TECH FIG 2E). If alignment is not optimal, the bone preparation should be repeated until alignment is ideal.

   

  Slight plantarflexion to both the proximal and distal preparations should place the hallux IPJ in approximately 5 degrees of flexion.

   

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  TECH FIG 2 • (continued) C,D. Distal phalanx preparation. C. Relatively minimal bone resection. D. More bone is resected dorsally than plantarly to promote slight plantarflexion. E. Intraoperative fluoroscopy with prepared surfaces reduced to confirm satisfactory bony alignment prior to fixation.

• Guidewire Placement

   

  A guidewire is placed in retrograde fashion from inside the joint through the center of the distal phalangeal base, aiming longitudinally with the exit point at the distal toe immediately inferior to the nail bed (TECH FIG 3A).

   

  A small transverse incision is made at the exit point of the guidewire along the direction of Langer lines (TECH FIG 3B).

   

  The guidewire is backed into the distal phalanx except for 1 or 2 mm (TECH FIG 3C). This spike allows for anchoring into the center of proximal phalanx medullary canal.

   

  The guidewire is advanced after the alignment, translation, and rotation of the hallux IPJ and is satisfactory clinically and fluoroscopically (TECH FIG 3D).

   

   

   

  TECH FIG 3 • A. The guide pin for the cannulated screw is first driven antegrade across the distal phalanx. B. Transverse stab incision at distal toe to allow depth gauge, drill, and screw to be placed. C. The guide pin is driven retrograde in preparation for reduction of the arthrodesis. D. With the arthrodesis reduced and the toe in satisfactory alignment and rotation, the guide pin is driven retrograde across the arthrodesis site into the proximal phalanx. E. Intraoperative fluoroscopy to confirm optimal guide pin position. On this lateral view, the pin is in satisfactory position within the distal phalanx so that the screw will not violate the nail matrix.

   

   

   

  The depth to which the guidewire is advanced determines the screw length. The bony apposition, alignment, and translation are again confirmed under fluoroscopy. Care must be taken to leave adequate space for the screw to be inserted. Should the screw violate the nail matrix, it may create symptoms and potentially affect nail growth (TECH FIG 3E).

   

• Screw Insertion

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  After confirmation of satisfactory joint preparation and ideal guidewire position and determination of screw length using the dedicated depth gauge, the guidewire is overdrilled with a cannulated drill (TECH FIG 4A). We only drill to immediately across the arthrodesis site, not the full length of the proximal phalanx, in order to optimize screw purchase in the proximal phalanx.

   

   

   

  TECH FIG 4 • A. The guide pin is overdrilled. B. With the arthrodesis being stabilized with one hand, the screw is advanced from the distal phalanx into the proximal phalanx. Note that rotation is controlled. C. Fluoroscopic visualization of the screw being advanced across the arthrodesis site. D. If the arthrodesis is not stabilized, the distal phalanx could rotate into pronation. E. Ideally, the hallux nail should be rotated to match the rotation of the second toe nail. F. Intraoperative fluoroscopy suggesting the screw should be advanced further to optimize compression. The screw head should be buried within the tip of the distal phalanx.

   

   

  The screw of proper length is selected and inserted (TECH FIG 4B,C). The IPJ should be held securely in one hand as the screw is advanced with the other to be sure proper rotation and compression are maintained (TECH FIG 4D,E).

   

  Final AP, lateral, and oblique fluoroscopic images confirm sustained bony apposition, alignment, and screw position (TECH FIG 4F).

• Closure

   

  Wound closure starts with mattress closure of the residual capsule and transected EHL using 2-0 Vicryl (TECH FIG 5A).

   

  Subcutaneous tissue is closed with 3-0 Vicryl suture, and skin is reapproximated with 4-0 Nylon vertical mattress sutures to a tensionless closure (TECH FIG 5B).

   

  Sterile dressings are applied with abundant padding.

   

  If the patient can reliably protect the forefoot, a postoperative shoe that extends beyond the toes may be applied. If there is a concern that the patient may not be able to protect the forefoot, then we favor a short-leg splint with the ankle in neutral position, reinforced with a forefoot spica splint to protect the hallux.

   

   

   

  TECH FIG 5 • A. The capsule and EHL tendon are reapproximated. B. The skin edges of the H-shaped incision are reapproximated to a tensionless closure.

   

   

   

• Additional Case

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A 55-year-old woman with cock-up toe deformity had status post forefoot reconstruction with excision of both sesamoids in two prior surgeries (TECH FIG 6A).

 

Radiographs demonstrate residual hallux valgus, hallux IPJ arthritis, and cock-up toe deformity (TECH FIG 6B,C).

 

We performed a dorsal approach to prepare the IPJ for arthrodesis.

 

Through the joint we identified the FHL tendon, released the tendon from the plantar-distal phalanx, and placed a suture in the distal tendon (TECH FIG 6D).

 

 

 

TECH FIG 6 • A. Cock-up toe deformity in 55-year-old patient who had both sesamoids removed. AP (B) and lateral (C) radiographs. D. FHL tendon harvest through IPJ preparation. E. IPJ arthrodesis and drill hole proximal to fixation to allow for FHL tendon transfer to base of proximal phalanx. F. FHL tendon being transferred through base of proximal phalanx. G. FHL fixation with interference screw, prior to IPJ arthrodesis fixation.

 

 

We performed the hallux IPJ arthrodesis but left the screw (and a pin to control rotation) slightly short within the proximal phalanx (TECH FIG 6E).

 

By leaving the screw slightly short, enough space remained to create a drill hole in the base of the proximal phalanx to transfer the FHL tendon from plantar to dorsal. We secured the FHL tendon in the base of the proximal phalanx with an interference screw (TECH FIG 6F,G).

 

PEARLS AND PITFALLS
	Proper ▪ The starting point must be centered in the phalanges and directed along the guidewire center of the medullary canals. Deviating dorsally in the distal phalanx may cause placement the screw to violate the nail matrix, creating symptoms and potential aberrant nail growth. Wire and screw deviation in other directions may limit optimal compression and screw purchase.     Anatomic ▪ Proper distal phalanx rotation must be maintained until screw is fully seated and hallux compression is applied. A reasonable reference point is the second toe nail: The rotation hallux nail should have the same rotational alignment as the second toe. If any error is made, it should be into supination; pronation must be avoided.   Translation ▪ Maximum fusion contact surface area is dependent on optimal alignment between between the distal and proximal phalanges. At the arthrodesis site, the distal phalanx surface

 

	the two is usually greater than that of the proximal phalanx, so balance between the two is phalanges important to create ideal chance for fusion. Translation of the distal phalanx in relation to the proximal phalanx may also create symptomatic prominences.     Perform ▪ Extension of the arthrodesis tends to create a callus under the hallux IPJ arthrodesis arthrodesis site. in slight flexion.     Protect the ▪ The FHL tendon lies immediately deep to the hallux IPJ and overpenetration of the FHL saw blade may damage the FHL. tendon.
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POSTOPERATIVE CARE

 

Until follow-up at 10 to 14 days, the patient maintains protected weight-bearing restrictions in either a postoperative shoe or a splint.

 

Sutures are typically removed at first follow-up visit.

 

We routinely continue protected weight bearing in a postoperative stiff-soled shoe for 6 weeks, with weight bearing allowed on the heel.

 

FIG 3 • Follow-up of IPJ arthrodesis with FHL tendon transfer for cock-up toe deformity secondary to both sesamoids being excised (same patient as in TECH FIG 6). A. Toe neutral. B. MTP joint dorsiflexion. C. Lateral view of toe in neutral position (note intentional slight residual flexion of IPJ arthrodesis). D. Lateral view of MTP joint dorsiflexion. AP ( E) and lateral ( F) radiographs at 18-month follow-up and after removal of hardware.

 

OUTCOMES

Dhukaram et al reported a case series on 20 patients after hallux IPJ fusion using 3.5-mm screw fixation. All subjects were pain free at the final mean follow-up of 19 months with fusion rate of 100%.

At 18-month follow-up of the patient in TECH FIG 6, after hardware removal, hallux alignment and function had improved (FIG 3).

 

 

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COMPLICATIONS

Wound complications Infection

 

 

 

Malrotation

Malunion Nonunion

 

 

SUGGESTED READINGS

1. Salleh R, Beischer A, Edwards WH. Disorders of the hallucal interphalangeal joint. Foot Ankle Clin 2005;10(1):129-140.

    

    

2. Shives TC, Johnson KA. Arthrodesis of the interphalangeal joint of the great toe—an improved technique. Foot Ankle. 1980;1(1):26-29.