A navicular stress fracture is a common overuse injury in active athletes. We see this injury in runners, basketballers, track and field athletes, and soccer players. Male athletes are more at risk. In many cases, the diagnosis is late. So, how do you diagnose and treat a navicular bone stress fracture?
Why Does a Navicular Stress Fracture Occur?
There are several reasons why the navicular bone is susceptible to bone stress.
First, the bone is positioned in the mid-foot, which means high forces are applied to it during a foot strike. Second, the blood supply to the central portion of the bone is poor, which means that healing is compromised if not treated correctly. Finally, as the pain is mild in the early stages, most athletes push on with activity, leading to a greater chance of bone stress progression.
Risk factors for a navicular stress fracture include abnormal foot biomechanics such as high arches or flat feet, a sudden increase in training volume or intensity, relative energy deficiency syndrome (RED-S) and Vitamin D deficiency. A recent study found that more than 50% of patients with a stress fracture had Vitamin D deficiency.
Symptoms
Usually, pain is vague and not specific to any one point. Athletes often point to the ankle, mid-foot, or inside arch of the foot. Generally, pain is worse with training and improves with rest. Athletes usually keep training as the pain is not as bad as other stress fractures. As a result, this leads to a delay in diagnosis.
We suspect a navicular stress fracture if there is tenderness in the body of the navicular bone. In 80% of cases, people are tender at the ‘N’ spot. Sometimes, there is stiffness in the ankle and mild focal swelling in the mid-foot.
Usually, X-rays do not detect navicular stress fractures. Often, we need an MRI scan to see swelling and a break in the navicular bone. A CT scan is helpful to grade the fracture (1-3 grades), including whether it has the potential to heal or needs surgery. Sclerosis at the fracture sites signifies poor healing potential. Also, repeat CT can be used to monitor healing.
Treatment of a navicular stress fracture
We treat most cases of navicular bone stress without surgery. However, treating this fracture right the first time is essential, as healing is poor.
Indications for conservative management include:
- Stress reaction of the navicular without a fracture line
- A grade 1 navicular stress fracture
We recommend a cast or boot with crutches for six weeks. Then, transitioning from a walking boot to a shoe should take another 2-4 weeks. At this time, intensive therapy is essential to returning movement and strength to the ankle and calf. Balance exercises are crucial. Also, proper shoes and orthotics can help reduce the load on the navicular. We monitor bone healing with a repeat MRI and/or CT scan. If healing progresses well, the athlete returns to running and sports gradually over another 6 weeks. The total time to return to sport is approximately four months.
Other treatments that help bone healing include optimising Vitamin D and calcium intake, focused shockwave therapy, and LIPUS therapy. Further investigations, such as blood or a bone density test, are sometimes needed to assess bone health.
Navicular stress fracture surgery
Indications for surgery include:
- Non-union with conservative management
- A grade 2 or 3 navicular stress fracture
Usually, surgeons perform surgery with a screw to fix the fracture, followed by non-weight bearing in a boot for at least six weeks. Sometimes, surgeons use a bone graft to help with bony union.
A recent review compared conservative management to surgical fixation. The authors found that operative management provides a higher success rate (99% vs 73%) and lower non-union rate than conservative management. However, the time to return to play was similar in both groups (4-5 months).
Other frequently asked questions about navicular stress fracture:
What are other causes of pain near the navicular bone?
Other possible causes of mid-foot pain include tibialis posterior tendonitis, mid-foot arthritis, accessory navicular syndrome, deltoid ligament injury and tarsal coalition.
Can a navicular stress fracture be treated successfully with rest from sport without a boot?
We think not. One study found that only 10% of patients with a navicular stress fracture treated with partial weight-bearing rest returned to sport after a year. These results indicate that partial or full weight-bearing treatment is inadequate for these injuries. Non-weight-bearing treatment is more successful and the preferred conservative treatment.
What other treatments help bone healing with a navicular stress fracture?
LIPUS, or low-pulsed ultrasound, has shown potential in healing complex stress fractures. It needs to be used every day for at least two months. Also, high-dose Vitamin D supplementation may help accelerate healing in people with low Vitamin D levels.
Final word from Sportdoctorlondon about a navicular stress fracture
Consider a navicular stress fracture in a runner or athlete with medial ankle or mid-foot pain. Early diagnosis means a better outlook and quicker recovery.
Leave A Comment