Last Updated on March 3, 2024
Iselin disease is osteochondrosis or epiphysitis of the base of the fifth metatarsal. It is also known as traction apophysitis or epiphysitis of the fifth metatarsal base. Hans Iselin, a German surgeon, described the condition. He described this in 1912 as occurring in young adolescents at the time of the appearance of the proximal epiphysis [growth plate] of the fifth metatarsal.
Iselin disease is a benign and self-limiting condition. The exact etiology is unknown though repetitive traction of the peroneus brevis tendon at the site of its attachment is thought to be the predominant reason.
The apophysis is within the peroneus brevis tendon insertion site.
Iselin disease is more common in football players, basketball players, gymnasts, and dancers. Any person with repetitive inversion stress is at risk. However, the condition itself is quite rare.
The affected epiphysis is a small, shell-shaped fleck of bone located on the lateral plantar aspect of the tuberosity of the fifth metatarsal. It is not visible on anteroposterior or lateral radiographs and can be seen in the oblique view.
Peroneus brevis muscle insertion is in the vicinity of this epiphysis.
The epiphysis appears in girls at about age 10 years and in boys at about age 12 years and is fused about 2 years later.
Relevant Anatomy
The fifth metatarsal bone is one of the five metatarsal bones of the foot. It is a long bone consisting of a head, body, and base. It presents two surfaces – medial and lateral.
The fifth metatarsal lies between the cuboid bone proximally and the proximal phalanx of the little toe, lying lateral to the fourth metatarsal.
It ossifies by three ossification centers in the base, the head of the metatarsal which appears during the second to fourth years. The secondary epiphysis of the base or the apophysis of the proximal 5th metatarsal appears at age 12 years in boys and 10 in girls. Fusion of the apophysis to the metatarsal base usually occurs within the after 2-4 years.
Pathophysiology of Iselin Disease
Iselin disease is thought to be due to overuse injury and repetitive pressure during athletic activities and the traction by the inserted muscle is thought to contribute to the pathophysiology.
With the growth of organized sports especially in younger age groups, overuse injuries are becoming more frequent.
The traction apophyses of the fifth metatarsal, a site of active growth might be injured as a result of either macrotrauma or repetitive microtrauma (overuse).
This might result in pain, swelling, and occasional bony and cartilaginous overgrowths referred to as apophysitis.
In addition, rapid growth periods in a child or adolescent can cause muscle-tendon tightness and can lead to a potential for tiny avulsion fractures at the weak apophyseal growth cartilage. When this occurs at the bases of the fifth metatarsal, Iselin disease occurs.
Presentation and Diagnosis
Pain at the outer aspect of the foot that worsens with activity is the usual presentation. There is a visible prominence of the proximal part of the base of the fifth metatarsal. Weight-bearing produces pain over the lateral aspect of the foot. The pain develops gradually and is exacerbated by activities like jogging and leaping.
The pain eases with rest initially but, later, it may persist and interfere with daily routines. Some persons may have a limp.
on examination, the affected area over the tuberosity is larger on the involved side, with soft-tissue edema and local erythema. On palpation the area is tender. Resisted eversion, extreme plantar flexion, and dorsiflexion of the foot cause pain.
The diagnosis of Iselin Disease should be considered in adolescents who are active in sports and present with symptoms.
Differential Diagnoses
- Jones’ fracture [fracture of base of the fifth metatarsal
- Stress fractures of the fifth metatarsal
- Os Velanium
- Normal apophysis
- Avulsion fracture of styloid of 5th metatarsal
Imaging in Iselin Disease
X-rays
Routine foot X-rays include AP, lateral, and oblique views. In Iselin disease, oblique radiographs show enlargement and often fragmentation of the epiphysis and widening of the cartilaginous-osseous junction. X-ray of the other foot may be used for comparison.
On X-rays, a normal variant which appears as a small fleck of bone that is oblique to the fifth metatarsal shaft and on the lateral aspect of the tuberosity is found in most children. However, there would not be any clinical symptoms. It may show an enlarged apophysis with disordered ossification. A widened chondro-osseous junction may be seen.
For diagnosis of Iselin disease, the radiographic finding must correlate with clinical symptoms.
On x-rays, in addition to the differentials mentioned above, another entity that needs to be diagnosed is os vesalianum, an accessory bone found proximal to the base of the fifth metatarsal.
There would be an absence of symptoms in Os Vesalianum.
Bone Scan
Technetium-99m bone scanning shows increased uptake over the epiphysis. But this investigation is often not needed for the diagnosis.
Treatment of Iselin Disease
The treatment of Iselin disease ranges from conservative to operative.
Rest, Pain Relief Drugs and Activity Avoidance
Rest to the part and ice fomentation help to decrease inflammation in mild cases. If tenderness and inflammation do not resolve, oral nonsteroidal anti-inflammatories (NSAIDs) can be added.
Plaster Cast Immobilization
If symptoms return on discontinuation of medication, or symptoms are moderate to severe, immobilization with air cast or plaster cast may be used and the patient is kept non-weight bearing. After 2-4 weeks a range of motion exercises can be initiated.
Surgery
If conservative treatment fails, there is a risk of fragments going into nonunion and surgical intervention like resection of the fragment or fixation at the nonunion site.
Excision is recommended only if the excised bone does not interfere with the function of the peroneus brevis tendon or stability of gait
Return to Sports or Activity
Return to sports activity should be gradual and supervised. The return to sports and activity can be considered after a period of healing that ranges from 4 to 12 weeks. The patient should be able to
- Absence of pain at rest or on walking
- Complete range of ankle motion
- Sprint/jog without pain
- Hop on the affected foot without pain
If the pain recurs on initiating activity, the patient should again take the rest.
Prevention
The risk of Iselin disease can be reduced by the following
- Proper warm-ups before starting any activity
- Choosing the proper footwear to wear
- Stretches before exercise
- Rest if pain occurs. Don’t continue to play if the pain occurs.
Image credits: For both images orthobullets.com
References
- Deniz G, Kose O, Guneri B, Duygun F. Traction apophysitis of the fifth metatarsal base in a child: Iselin’s disease. BMJ Case Rep. 2014 May 15;2014:bcr2014204687. [Link]
- Forrester RA, Eyre-Brook AI, Mannan K. Iselin’s Disease: A Systematic Review. J Foot Ankle Surg. 2017 Sep-Oct;56(5):1065-1069. [Link]
