Iselin’s disease, or traction apophysitis of the fifth metatarsal base, represents a distinctive and often under-recognized chapter in the spectrum of pediatric orthopedic conditions. First described by German surgeon Hans Iselin in 1912, it involves inflammation and irritation of the growth plate (apophysis) at the base of the fifth metatarsal, where the peroneus brevis tendon inserts. Unlike the more familiar Sever’s disease (heel) or Osgood-Schlatter disease (knee), Iselin’s disease occupies a unique anatomical and biomechanical niche in the growing foot. Its treatment, therefore, is not a matter of standardized protocol but a nuanced, multi-faceted journey that balances physiological healing, biomechanical correction, and the unique demands of the active pediatric patient.
The cornerstone of managing Iselin’s disease rests upon an accurate diagnosis, as its presentation can mimic more severe injuries like acute fractures or Jones fractures. It typically affects adolescents, most commonly between the ages of 8 and 14 in girls and 10 and 15 in boys, coinciding with the period of rapid growth preceding the fusion of this secondary ossification center. The patient, often an active child involved in running, cutting, or jumping sports, presents with lateral foot pain, localized swelling, and tenderness directly over the prominent bony protrusion at the outer edge of the midfoot. Pain is exacerbated by activity, especially pushing-off maneuvers, and may be accompanied by a mild limp. Radiographic confirmation is crucial, revealing a fragmentation or widening of the apophysis parallel to the metatarsal shaft, distinct from an acute fracture line. This diagnostic clarity is the first critical step in treatment, preventing unnecessary immobilization for a “sprain” or, conversely, failing to protect a true apophysitis.
The primary and most fundamental pillar of treatment is activity modification and relative rest. This does not mandate complete cessation of all movement—a near-impossibility for most children—but rather a strategic reduction or alteration of activities that provoke symptoms. The goal is to break the cycle of repetitive microtrauma caused by the pulling force of the peroneus brevis tendon on the vulnerable growth plate. Physicians and physical therapists often recommend a temporary hiatus from high-impact sports like soccer, basketball, or gymnastics for 4-6 weeks. During this period, cross-training with low-impact activities such as swimming or cycling is encouraged to maintain cardiovascular fitness and patient morale without stressing the apophysis. Education of the patient and parents is paramount here; understanding that this is an “overuse” injury related to growth, rather than a permanent weakness, fosters compliance and alleviates anxiety.
Concurrently, biomechanical management addresses the underlying forces contributing to the condition. The peroneus brevis, responsible for everting and plantarflexing the foot, is under increased tension during the mid-stance and push-off phases of gait. In children with pes planus (flat feet) or hindfoot valgus, this tension can be exaggerated. Therefore, a critical component of treatment is the use of orthotic support. Simple, over-the-counter arch supports or more custom-molded orthotics can help correct excessive pronation, stabilize the midfoot, and reduce the tensile load on the peroneus brevis insertion. Proper footwear evaluation is equally important. Recommending shoes with good lateral stability, a firm heel counter, and adequate cushioning can provide external support and dampen impact forces. For acute phases with significant swelling and pain, cryotherapy (ice application) for 15-20 minutes after activity helps manage inflammation and provides analgesic relief.
When pain persists despite conservative measures, a period of immobilization may be necessary. This is typically achieved with a removable walking boot or a controlled ankle motion (CAM) walker for 2-4 weeks. The boot serves a dual purpose: it significantly limits the pull of the peroneal tendons by restricting ankle motion, and it offloads the forefoot during weight-bearing. Crucially, because it is removable, it allows for hygiene, gentle range-of-motion exercises to prevent stiffness, and progressive reintegration of activity. In rare, severe, or recalcitrant cases where a child cannot comply with boot wear or symptoms are debilitating, a short-leg cast for 3-4 weeks may be employed as a last resort to enforce absolute rest.
Throughout the treatment continuum, physical therapy plays an indispensable role, evolving in focus as the condition improves. In the acute phase, therapy may focus on modalities for pain and inflammation (e.g., ultrasound, electrical stimulation) and gentle stretching of a potentially tight peroneal complex and Achilles tendon. As pain subsides, the emphasis shifts to strengthening the intrinsic foot muscles, the peroneals eccentrically, and the entire kinetic chain—including the gluteal muscles—to improve lower limb stability and alignment. Proprioceptive and balance training on uneven surfaces helps restore neuromuscular control, which is often deficient following a period of pain-induced gait alteration. This rehabilitative phase is essential not only for resolving the current episode but also for equipping the young athlete with the strength and mechanics to prevent recurrence.
Pharmacological intervention is generally minimal. Non-steroidal anti-inflammatory drugs (NSAIDs) like ibuprofen may be used judiciously for short-term pain and inflammation control. However, their role is adjunctive and not curative, as the core pathology is a mechanical traction rather than a primary inflammatory disorder. Corticosteroid injections are almost never indicated in Iselin’s disease, given the risk of growth plate injury, tendon weakening, and the self-limiting nature of the condition.
The timeline for return to sport must be gradual and criterion-based, not calendar-based. A child should be pain-free with daily activities before beginning a phased reintroduction. This might start with light jogging in straight lines, progress to sport-specific drills without cutting, and finally advance to full practice and competition. Any recurrence of pain is a signal to step back to the previous phase. The entire process, from diagnosis to full return, can take anywhere from 6 weeks to 4 months, requiring patience from all parties involved.
Finally, the prognosis and natural history of Iselin’s disease form the reassuring backdrop to all treatment. It is a self-limiting condition that resolves completely once the apophysis fuses to the main metatarsal shaft, typically by age 12-15 in girls and 14-16 in boys. The goal of treatment is not to alter this natural history, but to manage symptoms, prevent prolonged disability, and allow safe participation in the activities crucial to a child’s physical and social development. Complications are exceedingly rare, and no long-term functional deficits are expected.
The treatment of Iselin’s disease in the foot is a comprehensive, patient-centered endeavor. It navigates the intersection of pediatric growth physiology, sports biomechanics, and behavioral psychology. Successful management hinges on a clear diagnosis, a stepwise approach integrating rest, support, and rehabilitation, and a compassionate understanding of the young patient’s world. By demystifying the condition and providing a structured path to recovery, clinicians can effectively guide children and their families through this transient yet challenging phase, ensuring a swift and confident return to the active childhood they deserve.