This article is guest blogged by Amol Saxena, a Podiatrist at the Palo Alto Medical Foundation near Stanford. Visit Dr. Saxena’s website at www.amolsaxena.com
Navicular stress fractures by Amol Saxena, DPM
Until recently, little has been known about these injuries. Unfortunately they often get mis-diagnosed as arch pain, plantar fasciitis and various strains, or arthritis (which, if untreated can end up arthritic). The classic symptoms are pain on the top of the foot right where it joins the ankle, on the center point of the Navicular (arch) bone. This is known as the “N-spot”. Pain increases with activity, particularly with sprinting, bounding or being “en pointe” (on your toes). Sometimes symptoms come about gradually and other times it can occur acutely; an ankle sprain can precipitate a stress “riser” to the top of the foot. There is generally little swelling or bruising but there is often a dull ache, throbbing; sharp pain can occur with intense activity or when the stress fracture breaks completely.
There is confusion about the best test to show a Navicular stress fracture (NSF), but there should not be. It is true that plain X-rays can miss the injury, but bone scans are always positive, however they do not localize the fracture detail. Similarly, MRI scans can show a NSF almost always but they do not show bony detail. Saxena et al reported on a NSF classification system that was correlated with healing time and severity using CAT scans. It is important to get a CAT for Navicular stress fractures. Sometimes there is concern about radiation but modern CAT scans have such short scanning time, this ends up the same radiation as a X-ray. A Type I NSF is a crack in the top of the Navicular bone. If caught early (within 6 wks) these often can heal non-surgically, however, patients need to be in a cast boot for 6 weeks, non-weightbearing, and an additional 4-6 weeks weightbearing in the boot (until pain-free). Type II NSF have the fracture line extending deeper into the Navicular bone. Non-surgical treatment is an option, but many athletes elect to have surgical treatment, as re-fracture, arthritis or giving up on sports is common. Type III injuries are fractures that go from the top of the Navicular bone, through it, and out another side (complete fracture). These can be treated non-surgically but have even higher incidence of all the bad things that can also happen with Type II NSF. In fact in a paper by Saxena and Fullem, they found many patients they ended up operating on already had failed non-surgical treatment at least once with Type II and III injuries.
Surgery usually requires general anesthesia and involves placing one or two screws across the fracture to compress it and allow for healing. (Rarely do the screws need to be removed, though with some sports such as soccer, removal may be beneficial.) Bone graft from your own body may be used particularly for older injuries. Bone stimulators can be used (and even for non-surgical treatment) but it is important to have proper non-weightbearing and protection in a cast or boot for several weeks. Patients can ride stationary bikes with the boot on, swim at some point, but return to sport is usually 12 or more weeks. Saxena and Fullem have reported on the largest number of cases of NSF in North America, and most athletes who have surgery are able to resume sports. Some authors claim all NSF should be treated non-surgically first, however the data from experienced authors who have long-term follow-up does strongly favor immediate surgical intervention at least for Type II and II injuries. Many other studies do not report whether athletes eventually go elsewhere for surgery, give up their sport, nor do they reveal about arthritis, etc. Follow-up CAT scans are sometime needed to assess healing. MRIs are inconclusive. Fullem and Saxena recently reported on a less severe Navicular injury (termed Type 0.5) which there is dorsal pain, a positive bone scan and MRI but a negative CAT scan). These can be treated with a shorter period of non-weightbearing (3 weeks) and a boot (4-6 weeks) with a faster return to activity (RTA). It is difficult to say exactly what causes them as both high- and low-arched feet are associated, though high intensity training often precipitates them. Navicular stress fractures are usually season ending injuries, however, if evaluated, staged, and treated properly initially, they do not have to be career ending.
About the Author:
Dr Saxena is also:
- Fellow, American College of Foot & Ankle Surgeons
- Board Certified, Foot, Reconstructive Rearfoot & Ankle Surgery
- Chief, Division of Podiatric Surgery, Stanford Hospital
- Consultant, USA Track & Field
1.Burne, Sg, Mahoney CM, Forster BB, Koehle MS, Taunton JE, Khan KM. Tarsal Navicular Stress Injury Long-term Outcome and Clinico-radiological Correlation Using Both Computed Tomography and Magnetic Resonance Imaging. Am J Sports med. 2005;33(12):1875-1881
2. Haverstock BD. Stress Fracture of the Foot and Ankle. Clin Podiatr Med Surg 2001;18 (2):273-84.
3. Lee S, Anderson RB. Stress Fractures of the Tarsal Navicular. Foot Ankle Clin. 2004 Mar;9(1):85-104.
4. Saxena A, Fullem B, Hannaford D. Results of Treatment of 22 Navicular Stress Fractures and a New Proposed Radiographic Classification System J. Foot Ankle Surg. 2000;39 (2):96-103
5. Saxena A, Fullem B. Navicular Stress Fracture: A Prospective Study on Athletes. Foot Ankle Int. 2006;27(11):917-921.
6. Saxena A, Fullem B. Comment on Torg et al “Management of tarsal Navicular stress fractures: conservative versus surgical treatment”. Am J Sports Med 2010 38(10); 3-5