Iselin's Disease: Understanding, Causes, Symptoms, and Treatment

What is Iselin's disease Physiopedia?

Iselin's disease is a rare, self-limiting condition characterized by painful inflammation of the apophysis (growth plate) at the base of the fifth metatarsal bone in the foot, primarily affecting active children and adolescents.

Understanding Iselin's Disease

Iselin's disease, also known as fifth metatarsal apophysitis, is a form of osteochondrosis, which refers to a group of disorders that affect the growth plates in children and adolescents. Specifically, Iselin's disease involves the apophysis located at the proximal (base) end of the fifth metatarsal bone. This apophysis is a secondary ossification center, a cartilaginous area where bone growth occurs and where tendons or ligaments attach. In this case, it is the attachment site for the peroneus brevis tendon, a muscle that helps evert (turn outward) and plantarflex the foot.

Key Anatomical Structures Involved:

• Fifth Metatarsal: The long bone connecting the little toe to the midfoot.
• Proximal Epiphysis/Apophysis: The growth plate at the base of the fifth metatarsal. This area is cartilaginous and vulnerable to stress during periods of rapid growth.
• Peroneus Brevis Tendon: This tendon inserts onto the tubercle at the base of the fifth metatarsal. Its repetitive pulling on the vulnerable growth plate is a primary contributing factor to Iselin's disease.

Causes and Risk Factors

The exact cause of Iselin's disease is believed to be multifactorial, primarily involving repetitive traction or stress on the growth plate of the fifth metatarsal by the peroneus brevis tendon.

Mechanism of Injury:

• Repetitive Microtrauma: Activities involving frequent ankle eversion (turning the sole of the foot outward), inversion (turning the sole inward) with a strong contraction of the peroneus brevis to stabilize the ankle, or high-impact activities like running, jumping, and cutting, can lead to repetitive pulling on the developing growth plate.
• Growth Spurts: Children and adolescents are particularly susceptible during periods of rapid growth, as their growth plates are still cartilaginous and weaker than mature bone, making them more vulnerable to injury.

Common Activities and Demographics:

• Sports Participation: Iselin's disease is common in young athletes participating in sports that involve running, jumping, quick changes of direction, and repetitive ankle movements, such as soccer, basketball, gymnastics, and dance.
• Age Group: Typically affects children between 8 and 14 years of age, with a slightly higher incidence in boys. The condition resolves when the growth plate fuses, usually by late adolescence.

Contributing Factors:

• Improper Footwear: Shoes that lack adequate support or cushioning can increase stress on the foot.
• Biomechanical Issues: Foot mechanics, such as pes planus (flat feet) or pes cavus (high arches), or muscular imbalances, can alter stress distribution.
• Sudden Increase in Activity: Rapid escalation of training intensity, duration, or frequency without adequate conditioning.

Signs and Symptoms

The presentation of Iselin's disease is typically localized and related to physical activity.

Primary Symptoms:

• Lateral Foot Pain: Pain on the outside of the foot, specifically at the base of the fifth metatarsal.
• Pain with Activity: The pain often worsens during or after physical activity, especially running, jumping, or activities that involve pushing off the outer border of the foot.
• Tenderness to Touch: Localized tenderness upon palpation of the base of the fifth metatarsal.
• Swelling: Mild swelling or puffiness may be present around the affected area.
• Limping: The child may develop a limp, particularly after activity or at the end of the day, to offload the painful area.
• Pain with Ankle Movements: Pain may be exacerbated by resisted ankle eversion or dorsiflexion, which activates the peroneus brevis.

Distinguishing Features:

Unlike a traumatic fracture of the fifth metatarsal (e.g., a Jones fracture or avulsion fracture), Iselin's disease typically has a more gradual onset and is related to overuse rather than a single acute injury. However, differentiating these conditions often requires imaging.

Diagnosis

Diagnosis of Iselin's disease is primarily clinical, based on the patient's history and a physical examination, often supported by imaging studies.

Clinical Examination:

• Patient History: The clinician will inquire about the onset of pain, aggravating and alleviating factors, and the child's activity level and sports participation.
• Palpation: Direct palpation of the base of the fifth metatarsal will typically elicit localized tenderness.
• Range of Motion: Assessment of ankle and foot range of motion, noting any pain with resisted eversion or dorsiflexion.
• Gait Analysis: Observation of the child's walking pattern for any compensatory limping.

Imaging Studies:

• X-rays: Plain radiographs (AP, lateral, and oblique views of the foot) are the primary imaging modality. They are used to:
  • Confirm the presence of an open growth plate at the base of the fifth metatarsal.
  • Rule out other conditions, such as an acute fracture (e.g., Jones fracture, avulsion fracture) or stress fracture, which can present similarly.
  • In Iselin's disease, X-rays may show fragmentation or sclerosis (hardening) of the apophysis, or an irregular appearance of the growth plate, but these findings are often subtle.
• MRI (Magnetic Resonance Imaging): Rarely necessary for diagnosis but may be considered in equivocal cases or when other pathologies (e.g., bone contusion, tumor) need to be excluded. MRI can show inflammation and edema within the apophysis.

Differential Diagnosis:

It is crucial to differentiate Iselin's disease from other causes of lateral foot pain in children, including:

• Jones Fracture: A fracture in the diaphyseal-metaphyseal junction of the fifth metatarsal, typically caused by acute trauma.
• Avulsion Fracture: A small piece of bone pulled away by the peroneus brevis tendon, often due to an inversion injury.
• Stress Fracture: A hairline crack in the metatarsal bone due to repetitive stress.
• Peroneal Tendinopathy: Inflammation of the peroneal tendons.
• Cuboid Syndrome: Subluxation of the cuboid bone.

Management and Treatment

Management of Iselin's disease is overwhelmingly conservative, focusing on pain relief, reducing stress on the growth plate, and gradual return to activity. Surgical intervention is rarely, if ever, indicated.

Conservative Approaches:

• Rest and Activity Modification: This is the cornerstone of treatment. Complete cessation of aggravating activities (e.g., running, jumping sports) is often necessary until pain subsides. Participation in low-impact activities (e.g., swimming, cycling) may be permitted if pain-free.
• Pain Management:
  • Ice Application: Applying ice packs to the affected area for 15-20 minutes several times a day can help reduce pain and inflammation.
  • NSAIDs (Non-Steroidal Anti-Inflammatory Drugs): Over-the-counter NSAIDs like ibuprofen or naproxen may be used under parental guidance to manage pain and inflammation.
• Immobilization (Rarely): In severe cases or if pain persists despite activity modification, a short period of immobilization in a walking boot or cast may be considered, but this is uncommon.

Physical Therapy and Rehabilitation:

A structured physical therapy program is highly beneficial once acute pain has settled.

• Stretching: Focus on flexibility of the calf muscles (gastrocnemius and soleus) and peroneal muscles to reduce tension on the fifth metatarsal.
• Strengthening: Progressive strengthening exercises for the intrinsic foot muscles, ankle stabilizers, and hip abductors to improve overall lower limb mechanics and support.
• Biomechanical Assessment and Correction:
  • Footwear Analysis: Ensuring proper, supportive athletic footwear with adequate cushioning.
  • Orthotics: Custom or off-the-shelf orthotic inserts may be prescribed to correct excessive pronation or supination, redistribute pressure, and provide additional support.
  • Gait and Movement Pattern Retraining: Addressing any compensatory movement patterns during walking or sports-specific activities.
• Taping or Bracing: Kinesiology tape or ankle braces may provide temporary support and pain relief during the return-to-activity phase.

Prognosis and Return to Activity

The prognosis for Iselin's disease is excellent. It is a self-limiting condition that resolves completely with skeletal maturity when the growth plate fuses.

Recovery Timeline:

• Symptoms typically improve within weeks to a few months with appropriate rest and conservative management.
• Full resolution usually occurs within 6 to 12 months, though pain can persist intermittently until the growth plate closes.

Gradual Return to Activity:

• A progressive, pain-free return to sports and physical activity is crucial to prevent recurrence.
• This involves a phased approach:
  1. Start with low-impact activities.
  2. Gradually increase duration and intensity.
  3. Incorporate sport-specific drills once basic activities are pain-free.
  4. Full return to competitive play only when symptoms have completely resolved and strength/flexibility are restored.

Prevention Strategies:

While not entirely preventable, certain measures can reduce the risk:

• Appropriate Footwear: Wear supportive shoes that fit well and are appropriate for the activity.
• Gradual Progression: Avoid sudden increases in training volume or intensity.
• Warm-up and Cool-down: Incorporate proper warm-up routines before activity and cool-down stretches afterward.
• Stretching and Strengthening: Regular stretching of calf and peroneal muscles and strengthening of foot and ankle muscles.
• Rest and Recovery: Ensure adequate rest periods between training sessions and competitive events.
• Cross-Training: Encourage participation in a variety of sports or activities to avoid repetitive stress on one area.

Conclusion

Iselin's disease is a common cause of lateral foot pain in active children and adolescents, stemming from inflammation of the growth plate at the base of the fifth metatarsal. While painful and disruptive to activity, it is a benign, self-limiting condition with an excellent prognosis. With timely diagnosis, activity modification, and a structured rehabilitation program, young athletes can typically return to full, pain-free participation as their growth plates mature. Understanding its biomechanical basis and adhering to a conservative management plan are key to successful recovery.