Comprehensive Surgical Management of Lesser Toe Deformities and Forefoot Pathologies

Introduction to Lesser Ray Biomechanics and Pathoanatomy

The lesser rays of the foot function as a complex, dynamic unit designed to distribute weight-bearing forces during the stance phase of gait. Pathologies of the lesser toes—encompassing metatarsophalangeal (MTP) joint instability, hammer toes, mallet toes, intractable plantar keratosis (IPK), bunionettes, and Freiberg infraction—arise from a disruption in the delicate balance between intrinsic and extrinsic musculature, capsuloligamentous structures, and osseous alignment.

Surgical intervention is indicated when conservative measures (e.g., shoe modifications, orthoses, taping, and corticosteroid injections) fail to alleviate pain or halt progressive deformity. The following masterclass details the evidence-based surgical management of these conditions, synthesizing decades of orthopedic literature into actionable, step-by-step operative protocols.

Metatarsophalangeal Joint Instability and Crossover Toe Deformity

MTP joint instability most commonly affects the second ray and is characterized by progressive dorsal and medial subluxation, culminating in a "crossover toe" deformity. The primary pathoanatomic event is the attenuation or rupture of the plantar plate and the lateral collateral ligament complex.

Clinical Evaluation and Biomechanics

Patients typically present with localized pain beneath the second metatarsal head, swelling, and a positive "Lachman test" of the MTP joint (dorsal translation of the proximal phalanx >50% indicates significant plantar plate incompetence).

Clinical Pearl: Always evaluate for concomitant hallux valgus. A severe hallux valgus deformity often crowds the second toe, accelerating lateral ligamentous failure and medial deviation of the second digit. Correcting the second toe without addressing the first ray guarantees recurrence.

Surgical Techniques

1. Plantar Plate Repair and Weil Osteotomy

For direct anatomic restoration of the MTP joint, a primary plantar plate repair combined with a Weil (distal oblique metatarsal) osteotomy is the gold standard.

• Positioning: Supine with a calf tourniquet.
• Approach: A dorsal longitudinal incision is made over the second MTP joint.
• Soft Tissue Release: The extensor digitorum longus (EDL) is lengthened via a Z-plasty. A dorsal capsulotomy is performed, and the collateral ligaments are released to expose the metatarsal head.
• Weil Osteotomy:
  • Using an oscillating saw, an intra-articular osteotomy is initiated at the dorsal margin of the articular cartilage.
  • The cut is directed proximally and plantarly, parallel to the weight-bearing surface of the foot.
  • The capital fragment is translated proximally (typically 2–5 mm) to decompress the joint and relax the intrinsic musculature.
  • Fixation is achieved with a single dorsal-to-plantar twist-off screw or threaded Kirschner wire (K-wire).
• Plantar Plate Repair: With the joint decompressed, the torn plantar plate is identified. Suture passers are used to place non-absorbable sutures through the plantar plate, which are then passed through drill holes in the base of the proximal phalanx and tied dorsally.

2. Flexor-to-Extensor Tendon Transfer (Girdlestone-Taylor Procedure)

Indicated for dynamic stabilization of a flexible crossover toe deformity.
* Technique: The flexor digitorum longus (FDL) is harvested at the level of the distal interphalangeal (DIP) joint. It is split longitudinally into two slips.
* The slips are routed dorsally along the medial and lateral aspects of the proximal phalanx.
* With the ankle at neutral and the toe held in slight plantarflexion, the slips are sutured to the extensor expansion over the dorsal proximal phalanx.

Hammer Toe Deformity

A hammer toe is defined by an extension contracture at the MTP joint and a flexion contracture at the proximal interphalangeal (PIP) joint, with the DIP joint remaining neutral or extended. It results from an imbalance where the long extensors overpower the intrinsic lumbricals.

Indications and Preoperative Planning

Surgical planning depends on whether the deformity is flexible or rigid. Flexible deformities may be managed with soft tissue procedures (e.g., flexor tenotomy, extensor lengthening), whereas rigid deformities require osseous resection or arthrodesis.

Surgical Warning: Over-resection of the proximal phalanx head during PIP arthroplasty can lead to a "flail toe." Always resect conservatively, removing only the condyles necessary to achieve neutral alignment.

Surgical Approach: PIP Joint Arthrodesis / Resection Arthroplasty

• Incision: A dorsal longitudinal or transverse elliptical incision is made over the PIP joint. If a severe dorsal corn is present, an elliptical excision of the skin and bursa is performed.
• Exposure: The extensor tendon is transected transversely or split longitudinally to expose the PIP joint. The collateral ligaments are sharply excised to allow complete plantarflexion of the middle phalanx.
• Bone Resection:
  • Using a microsaw or bone rongeur, the head and neck of the proximal phalanx are resected at the metaphyseal-diaphyseal junction.
  • If an arthrodesis is planned (preferred for the 2nd toe to maintain rigidity), the articular cartilage of the base of the middle phalanx is also denuded.
• Fixation: A 0.045-inch or 0.062-inch K-wire is driven antegrade through the middle and distal phalanges, exiting the tip of the toe. The wire is then driven retrograde into the medullary canal of the proximal phalanx.
• MTP Joint Management: If MTP extension contracture persists after PIP correction, a sequential release is performed: EDL lengthening, dorsal capsulotomy, and finally, collateral ligament release.

Mallet Toe Deformity

Mallet toe is an isolated flexion deformity of the DIP joint, often resulting in a painful terminal corn at the tip of the toe or a dorsal corn over the DIP joint. It is driven by a tight FDL tendon.

Surgical Approach: DIP Joint Arthroplasty and FDL Tenotomy

• Incision: A dorsal transverse or elliptical incision over the DIP joint.
• Tendon Release: The extensor tendon is divided, and the collateral ligaments of the DIP joint are released.
• Bone Resection: The head of the middle phalanx is resected.
• FDL Tenotomy: If the deformity is severe, a percutaneous or open FDL tenotomy is performed at the plantar crease of the DIP joint.
• Fixation: The joint is reduced and stabilized with a longitudinal K-wire driven through the distal phalanx into the middle phalanx, remaining in place for 3 to 4 weeks.

Intractable Plantar Keratosis (Corns and Calluses)

Intractable plantar keratosis (IPK) is a focal, painful hyperkeratotic lesion on the plantar aspect of the foot, typically beneath one or more lesser metatarsal heads. It is a manifestation of altered biomechanics, where a plantarflexed or excessively long metatarsal bears disproportionate weight.

Biomechanical Considerations

Normal forefoot weight-bearing follows a parabolic curve. Disruption of this cascade—often due to a hypermobile first ray, prior hallux valgus surgery, or congenital metatarsal length discrepancies—shifts forces laterally, causing transfer metatarsalgia.

Surgical Management: Metatarsal Osteotomies

When conservative offloading fails, surgical elevation or shortening of the offending metatarsal is required.

1. Weil Osteotomy

As described above, the Weil osteotomy is highly effective for shortening the metatarsal without significantly elevating it, making it ideal for long metatarsals causing IPK.

2. Helal (Distal Oblique) Osteotomy

• Technique: A dorsal approach exposes the distal metatarsal shaft. An oblique osteotomy is made from dorsal-proximal to plantar-distal at a 45-degree angle.
• Mechanism: The distal fragment is allowed to slide proximally and dorsally, seeking its own biomechanical level.
• Pitfall: Unfixed Helal osteotomies have a high rate of nonunion, malunion, and transfer metatarsalgia. Modern practice dictates rigid internal fixation (screws or K-wires) once the desired elevation is achieved.

Clinical Pearl: Avoid excessive elevation of a single metatarsal head, as this will inevitably lead to transfer metatarsalgia to the adjacent ray. The goal is to restore the harmonious metatarsal parabola, not to completely unload the affected ray.

Bunionette (Tailor's Bunion) Deformity

A bunionette is a painful prominence on the lateral aspect of the fifth metatarsal head. It is categorized into three types based on radiographic findings:
* Type I: Enlarged lateral condyle of the fifth metatarsal head.
* Type II: Lateral bowing of the fifth metatarsal shaft.
* Type III: Increased fourth-fifth intermetatarsal angle (IMA > 8 degrees).

Surgical Techniques

1. Lateral Condylectomy (Type I)

• Approach: A dorsolateral incision over the fifth MTP joint.
• Resection: The lateral one-third of the metatarsal head is resected using an oscillating saw, ensuring the cut is parallel to the medial border of the foot. The capsule is imbricated during closure.

2. Distal Chevron Osteotomy (Type II and Mild Type III)

• Technique: Following a lateral eminence resection, a V-shaped osteotomy (apex distal) is made in the metatarsal neck.
• Translation: The capital fragment is translated medially by up to 50% of the shaft width.
• Fixation: Stabilized with a single K-wire or low-profile screw.

3. Diaphyseal or Basal Osteotomy (Severe Type III)

• Technique: For a significantly widened 4-5 IMA, an oblique diaphyseal osteotomy (Coughlin procedure) or a basal closing wedge osteotomy is required to achieve adequate medial translation of the entire fifth ray.
• Fixation: Rigid fixation with a plate and screws or multiple interfragmentary screws is mandatory due to the high torsional forces on the lateral column.

Freiberg Infraction

Freiberg infraction is an avascular necrosis (osteochondrosis) of the lesser metatarsal heads, most commonly affecting the second metatarsal in adolescent females. It leads to subchondral collapse, cartilage fragmentation, and secondary osteoarthritis.

Staging (Smillie Classification)

• Stage I: Fissuring of the epiphysis.
• Stage II: Central depression of the articular surface.
• Stage III: Central resorption with medial and lateral projections.
• Stage IV: Complete collapse of the metatarsal head with loose body formation.
• Stage V: End-stage arthrosis with joint space narrowing.

Surgical Management: Dorsal Closing Wedge Osteotomy (Gauthier Procedure)

For Smillie Stages II-IV, where the plantar cartilage remains viable, the dorsal closing wedge osteotomy is the procedure of choice.

• Positioning: Supine, calf tourniquet.
• Approach: Dorsal longitudinal incision over the affected MTP joint.
• Joint Debridement: A dorsal capsulotomy is performed. Loose bodies are excised, and the necrotic dorsal cartilage is debrided.
• Osteotomy:
  • A dorsal-based wedge of bone is resected from the metatarsal neck, just proximal to the articular surface.
  • The plantar cortex is left intact to act as a hinge.
• Rotation: The metatarsal head is rotated dorsally, closing the wedge. This maneuver rotates the healthy, viable plantar cartilage dorsally to articulate with the proximal phalanx.
• Fixation: The osteotomy is secured with crossed K-wires or a dorsal titanium staple.
• Postoperative Care: The patient is placed in a rigid postoperative shoe, weight-bearing on the heel for 4 to 6 weeks until radiographic union is observed.

Postoperative Protocols and Complication Management

General Rehabilitation

• Weeks 0-2: Patients are placed in a bulky compressive dressing and a rigid-soled postoperative shoe. Weight-bearing is restricted to the heel. Elevation is critical to minimize edema.
• Weeks 2-4: Sutures are removed. K-wires (if used for digit stabilization) remain in place. Taping of the toes in slight plantarflexion is initiated to prevent dorsal contracture.
• Weeks 4-6: K-wires are removed in the clinic. Active and passive range of motion (ROM) exercises of the MTP and PIP joints begin.
• Weeks 6-12: Transition to wide-toe-box footwear. Aggressive intrinsic muscle strengthening and plantar plate stretching are emphasized.

Managing Complications

1. Floating Toe: A common complication following Weil osteotomy, caused by the intrinsic muscles moving dorsal to the axis of rotation. Prevention involves meticulous plantar plate repair and avoiding excessive metatarsal shortening. Treatment requires flexor-to-extensor tendon transfer.
2. K-Wire Tract Infection: Managed with immediate wire removal and oral antibiotics. Deep infections are rare but require surgical debridement.
3. Recurrence of Deformity: Often due to unrecognized proximal pathology (e.g., uncorrected hallux valgus or equinus contracture). Revision surgery must address the primary biomechanical driver, potentially requiring arthrodesis of the MTP joint in severe, recalcitrant cases.

By adhering to these rigorous biomechanical principles and precise surgical techniques, orthopedic surgeons can reliably restore forefoot kinematics, alleviate pain, and achieve durable functional outcomes in patients with lesser toe deformities.

📚 Medical References

• Lesser toe deformities: an overview, Foot Ankle Clin 3:195, 1998.
• Thompson FM, Deland JT: