Introduction
Freiberg's infraction was first described by Dr. Alfred Freiberg in the year 1914 in a series of six patients who presented with a similar infarction (tissue death as a result of insufficient blood supply) pattern that affected the second metatarsal head. This infarction leads to the flattening and collapse of the metatarsal head, which further causes degenerative changes in the second metatarsophalangeal joint and further progresses to arthritis. Though a rare condition, necrosis (tissue death) due to infarction of the second metatarsal is one of the most common osteochondrosis.
What Are the Causes?
Osteochondrosis is a collective term that refers to a number of disorders that affect the growing skeleton. The exact cause of osteochondrosis is not known but includes a number of factors like repetitive trauma, genetic etiology, vascular anomalies, hormonal imbalances, and mechanical factors. Freiberg's infarction is one of the most common types of osteochondrosis. It is the only osteochondrosis that is prevalent more in females than males, with a relative ratio of 5:1.
It is commonly seen in adolescent girls who are dancers, athletes, or ballet performers. There is no dominance in the prevalence of the condition on one side compared to the other. But the condition affected both sides and was reported in less than 10 percent of the cases. The condition is most commonly seen between the ages of 11 and 17. The commonest anatomical location is the second metatarsal (68 percent of cases), followed by the third metatarsal (27 percent of cases), and then the fourth metatarsal (3 percent of cases). The fifth metatarsal is the least affected.
What Is the Anatomy?
The metatarsals (long bones of the forefoot region that lead to the toes) have two centers of ossification (bone formation). The primary ossification center is in the metatarsal shaft region, and the epiphyseal ossification center is in the lesser metatarsal head. The distal ossification regions develop by three to four years of age and fuse with the shaft region by the age of 17 to 20 years. Two arterial sources supply the metatarsal heads; the plantar and dorsal metatarsal arteries. Repetitive trauma can lead to a disrupted blood supply and necrosis in this region.
What Are the Symptoms?
The signs and symptoms include:
- Swelling and pain about the affected metatarsal head region of the forefoot.
- Symptoms worsen while walking, especially while wearing high heels or walking barefoot.
- There are often complaints of the sensation of walking on something hard, like stone.
- Physical evaluation reveals a swollen appearance in the metatarsophalangeal joint region.
- Sometimes presents with dorsiflexion (elevation of the toes).
- In advanced stages, malalignments like hammertoes are seen.
How Is the Condition Diagnosed?
The diagnosis is made based on clinical examination and radiographs. The initial radiographic finding shows a widening of the metatarsophalangeal joint space and joint effusion (an increase in intraarticular fluid accumulation). These findings are seen for three to six weeks after the appearance of symptoms. In the advanced stages, necrosis, sclerosis, and metatarsal head flattening are seen.
The classification system described by Smillie in 1957 is as follows:
- Stage 1 - A fissure fracture through the epiphysis. The absence of blood supply to the epiphysis is seen.
- Stage 2 - Cancellous bone absorption in the proximal region. A central depression is seen, but plantar cartilage remains intact.
- Stage 3 - The absorption continues, and central depression deepens while the plantar cartilage remains intact.
- Stage 4 - Restoration of normal anatomy is not possible at this stage. The central depression deepens, and plantar cartilage gets affected.
- Stage 5 - Flattening the metatarsal head and arthrosis (degenerative arthritis resulting in joint breakdown). The metatarsal shaft becomes dense and thicker.
In cases where radiographs are normal, MRI (magnetic resonance imaging) is used for evaluation. Nuclear medicine bone scans are also used in such cases. In the initial stages, bone scans show signs of early avascular necrosis.
What Are the Treatment Options?
The primary treatment goal for Freiberg's infraction treatment is pain reduction and the maintenance of a functional, non-pathologic gait. The secondary goal is the reduction or stoppage of progressive joint destruction.
1. Conservative Management:
- Conservative treatment options are ineffective if the condition has progressed to stage 4 or if loose bodies are found in the radiographs.
- Even then, conservative treatment options are trialed, and surgical treatment is only done in cases of failure.
- Conservative treatment options include:
- Weight-bearing restriction.
- Ultrasound therapy.
- Shoe gear modification.
- Padding.
- Orthotics.
- Anti-inflammatory medications.
- Steroid injections.
- The two phases of conservative treatment are protected mobilization and slowly returning to activity.
- Protected mobilization is done for two to six weeks or until symptoms subside.
- The protected mobilization methods include surgical shoes or removable walking boots, cast immobilization, or instructions on non-weight bearing.
- Most patients in stages 1 to 3 of the condition respond to conservative management, and long-term success is seen.
2. Surgical Management:
- Mostly indicated in stages 4 and 5 of the condition or in cases where conservative options fail.
- The surgical options aim to restore arthritic sequelae or alter the abnormal physiology. The procedures that are aimed at restoring arthritic sequelae include:
- Osteotomy.
- Grafting.
- Arthroplasty.
- Debridement.
- The procedures that are aimed at correcting abnormal physiology are:
- Corrective osteotomies.
- Core decompression.
What Is the Prognosis?
Most patients in stages 1 to 3 improve with conservative treatment options. But in advanced stages, surgical procedures are needed. The complication associated with Freiberg's infarction is that it can progress to an advanced stage of arthritis, increasing pain and limiting the range of motion.
What Is the Differential Diagnosis?
Based on clinical symptoms, the differential diagnosis includes:
- Gout (a painful form of arthritis due to the accumulation of urate crystals within the joint).
- Neuroma (nerve tissue tumor).
- Stress fracture.
- Rheumatoid arthritis (an autoimmune, painful inflammatory condition resulting in swelling, pain, and joint stiffness).
- Plantar plate tear.
Conclusion
Freiberg's infraction is a disorder that affects the growing skeleton. The second metatarsal is the commonest site. The symptoms include pain, swelling, dorsiflexion, and aggravation when walking. The diagnosis is mostly based on clinical and radiologic evaluations. Treatment options include conservative management and surgical interventions.
