Amol Saxena, DPM provides an outline for the current treatment of lower extremity stress fractures below the knee. Diagnostic and therapeutic modalities, including the indications for bone stimulation are reviewed. Difficult to heal injuries such as navicular and proximal lateral lesser metatarsal stress fractures are explained in detail. The listener should be able to definitively diagnose and treat these injuries after completing this session.
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Amol Saxena, DPM
Department of Sports Medicine
Palo Alto Medical Foundation
Palo Alto, CA
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STRESS FRACTURES OF THE FOOT, ANKLE, AND LEG
Hi, my name is Amol Saxena and I am a podiatrist at the Palo Alto Medical Foundation, Department of Sports Medicine at Palo Alto, California. We are going to talk about stress fractures of foot, ankle, and leg because it is very common for the podiatrist to have these type of pathologies presenting to them and there is not a lot of information on the specific treatment.
Stress fractures are cracks or pathological insufficiency fractures of bones. Stress fractures very commonly have pain that increases with activity. It is often very localized with throbbing and swelling. They can occur acutely. Some people think that they happen just in chronic situation but actually but many patients have no inkling that they are developing a stress fracture and have spontaneous intense acute pain. The patient is on anti��'inflammatories, actually seems to be more predisposes. Anti-inflammatories actually decrease bone mineralization, so patients prone to stress fracture or who may have one, should actually avoid anti-inflammatories. They should however take the minerals, calcium, and zinc, which seem to help with bone metabolism.
Nattiv and colleagues presented a study at the 2000 American College of Sports Medicine Meeting and if you view the findings that were significant for having a stress fracture versus other items that were not significant, it is actually quite surprising, particularly the biomechanical factors were not significant nor was menstrual status. This is a relatively small study and I believe never got published, however it does have some significant findings, particularly if the physician is dealing with track athletes.
Electrical bone stimulation has been shown to help slow healing bone, mineralize and create bony callus. They have been very-very _______ on how this occurs and part of the study was to see if bone stimulation would help stress fractures heal at an even faster rate.
For the stress fractures that are notoriously poorly healing, such as John’s fractures, use of electrical magnetic fields has been shown to be helpful.
The theory behind PEMF or pulse electrical magnetic fields is to stimulate vascularity and calcification of fibrocartilage, converting fibrocartilage into bony callus.
A review of the literature will show you the typical healing time of the stress fractures that are common in a podiatrist’s practice, particularly sports medicine. I think it is important to try to retrieve these studies and review them. It is also complete review of stress fractures and foot and ankle cordelle summer 2000 issue, an article written by myself.
In 1996, EBI helped support a study on the healing times of stress fractures. What I did was essentially just add electrical bone stimulation to the same treatment protocol for any type of stress fracture also treated during that time. So the treatment, otherwise was exactly the same. The only variable was application of a PEMF unit. This graph shows us controlled group and a typical healing time for the typical stress fractures that they encountered.
This graph shows the stress fractures that were treated with PEMF and the healing times and this was compared to the control group. We would like to thank EBI for supporting this study because they do not add that many units for these patients.
This is the preferred treatment for stress fractures below the knee, essentially all lower extremities stress fractures prior to retreat and again this can be reviewed in the summer issue 2000 of foot and ankle cordelle.
This is an x-ray of the patient who is training for the marathon at the Olympic trials and sustained a stress fracture and actually is what propagated the study because she had a typical treatment for a metatarsal stress fracture anomaly and a comminuted cut or pad, but the addition was an electronic bone stimulator and in 16 days an x-ray showed complete healing of her bony callus. Though resolution is not ideal, this does show the stress fracture had completely callused over. She was able to return to training or at least appear in the Olympic trials.
Stress fractures are common among the second and third metatarsals. Sometimes stress fractures continue to break down and essentially become a complete fracture as in this x-ray where the second metatarsal has bi-cortical break. This patient also sustained the stress fracture of the third metatarsal and this cortical break is just in the lateral aspect of the third metatarsal. Treatment typically in this situation when the fracture has become bi cortical is to use cast boot or a hi-top boot and then follow up with an accommodative orthosis.
Proximal fourth and fifth metatarsal stress fractures and fractures are very slow at healing. This shows an adducted forefoot and actually a group radiologist in 1999 determined that the adducted forefoot seems to be associated with proximal fifth and fourth metatarsal stress fractures.
This is a bone scan of the same patient of the previous x-ray and you can see intense increased uptake in the proximal fifth metatarsal consistent with a proximal fifth metatarsal stress fracture.
The difficult to heal fifth metatarsal stress fracture that are proximal, simple weight bearing is not effective at all. This patient was told he had a stress fracture and was able to walk on. You can see a significant nonunion.
In this type of situation where a proximal fifth metatarsal stress fractures occur, and it is fractured to the cortex, intramedullary screw fixation is the preferred treatment.
Some patients that have intramedullary screw fixation can re-fracture or breakdown. In this particular patient, he had twisted his foot about 3 months post ORIF for the 4.0 screw sustained a 6.5 screw with a bi-cortical apertures and autologous bone graft.
For proximal fifth metatarsal stress fractures, DeLee has shown very quick healing times as soon as 8 weeks with intramedullary screw fixation. Clapper show that ORIF was faster for the non-operative patients. Half of them ended up having surgery at any rate, therefore, an athletic patient’s surgery is definitely the best option.
What we started noticing in our clinic is that the proximal fourth metatarsals have delayed union similar to the fifth metatarsal John’s fractures. I found the association of the adducted forefoot and this treatment then was modified for these type of injuries to be very similar to the fifth metatarsal stress fractures, namely non-weight bearing.
This is a patient with a proximal fourth metatarsal stress fracture who has an adducted forefoot and medullary sclerosis.
This is another patient that has similar type of fracture in the proximal fourth metatarsal and went on to delayed union and eventually resolved with immobilization for 3 months and also a post electronic magnetic field unit.
In this case of 14-year-old soccer player, he had a fourth metatarsal stress fracture. X-ray fairly non-conclusive. No significant periosteal elevation.
On his MRI, he had intense signal change, particularly in the lower MRI T2 section with the entire bone being lit up and the top views are T1, which shows decreased signal in the medullary shaft. When you have a situation like this in a young patient, should also rule out Ewing sarcoma.
Therefore, in this 14��"year-old boy, a CT scan was ordered to rule out that, which was negative. So he essentially had a proximal fourth metatarsal stress fracture. He eventually was asymptomatic after about six months.
Therefore, proximal fourth metatarsal stress fractures are significantly slow healing injuries. They are in close proximity to the cuboid area and that may be why some of these patients are misdiagnosed as having cuboid syndrome. We report to keep them nonweightbearing for at least three weeks in a cast boot and protect it for at least two months, possibly longer. This paper was published in Foot and Ankle International in 2001 by myself and my colleagues Tom _______ and Sonia Erickson.
The patients with multiple stress fractures should be evaluated for metabolic pathologies and etiologies. One of my colleagues, Randy Linde and Day Feldman, both endocrinologists had a patient that had hypophosphatemic rickets with multiple stress fractures. Published this paper in journal Foot and Ankle Surgery in 2001 as well. A 51-year-old female had multiple forefoot stress fractures and had a low phosphate level. She was treated with calcium and phosphate supplementation.
Stress fractures can occur in the calcaneus, quite common in metabolic etiologies such as osteopenia postpartum. The patients have decreased calcium density. This is a patient who sustained bilateral calcaneal stress fracture after resuming a jogging program on hard surface with old running shoes.
These are the axial views of the same patient.
Calcaneal stress fractures can also occur due to plantar fasciitis due to the constant traction and the tug of the plantar fascia and these patients typically have plantar fasciitis symptoms that include throbbing, swelling, pain with side-to-side pressure and they tend to get worse with activity. Treatment involves below-knee cast boot with nonweightbearing for the first 3 weeks and weightbearing for additional 3 weeks.
A bone scan is often helpful in these type of patients but often the patients get an MRI, which also can show the same diagnostic pathology, namely a calcaneal stress fracture due to plantar fasciitis. Again, they would have pain with side-to-side pressure and pain getting worse with activity, swelling, and throbbing and the treatment is in a cast boot for nonweightbearing 3 weeks and additional 3 weeks, namely 6 weeks of immobilization. Sometimes, these take even longer to reduce the pathology.
Speaking of plantar fasciitis, some patients continue to have symptoms and walk on the lateral aspect of the foot. In this bone scan, the patient has findings consistent with plantar fasciitis but not intense enough for a stress fracture because the entire calcaneal tuberosity posteriorly does not lie down; however, has uptake in the lateral aspect of the cuboid and this is from lateralization due to compensation for the plantar fasciitis. This type of situation, the patient treats similarly as a calcaneal stress fracture, namely to utilize the cast boot for 6 weeks.
There is very little information particularly in podiatric literature on navicular stress fractures. So, my colleagues Brian Fullem, David Hannaford, and I collected our cases and published in the paper in 2000 journal, Foot and Ankle Surgery on navicular stress fractures. We wanted to see what the return to activity time was but also found an interesting pattern with these type of stress fractures on CT scan, hence reproduced a classification system and we find this useful in predicting the outcome and also proposed treatment.
We classify these injuries to type I, II, and III. Basically, type I is a cortical break in dorsal aspect navicular. Type II is a breakthrough in the navicular body. Type III is complete cortical break, both dorsal and the _______ propagating inferior or lateral.
A bone scan is a helpful test to help diagnose a navicular stress fracture. Often, it is an initial test after an x-ray but not necessarily the most conclusive.
We are going to show the use of some samples of these types of navicular fractures. So, again type I is a dorsal cortical break. This is an example of a feild hockey player who has an injury at the top of his foot and essentially the fracture became assist and on MRI sequence you can see the cystic change in the navicular, so this patient was treated with bone grafting and went on to a successful healing. This is the earliest type of stress fracture.
This is example of a healing type I navicular stress fracture that was treated with nonsurgical treatment. Often, these are cordelle and tend to heal with nonweightbearing and no surgery is needed.
Type II navicular stress fracture on CT is a fracture that extends into the body of the navicular. The S modifier shows that there is sclerosis or that this fracture is an older type and these often need surgical treatment including bone grafting and often a compression screw is inserted as well.
Here is another example of a type II S stress fractures. This patient was immobilized and kept nonweightbearing for 6 weeks, cast boot for 12 weeks but within about 6 months after starting running, he started getting symptoms again and that is the situation with these type of injuries as they often refracture or never completely go on to union. This usually requires treatment with bone graft and nonweightbearing.
Here is a example of a patient that had a bone graft for treatment of type II avascular necrosis or A type of injury and. Three years postop he is asymptomatic competing in sports and does not exhibit any degenerative changes at talonavicular joint, which is the area that often breaks down if these injuries go untreated.
Type III stress fracture on CT is a complete fracture from cortex to cortex. This makes the CT scan imperative. Multiple views are needed to fully assess the extent of the fracture. On the sagittal view of this patient, the CT scan shows a complete fracture to the navicular, whereas on the frontal plane image on the left, the fracture appears incomplete. He is recommended 1.5 mm axial CT slices.
This patient had a navicular fracture to the below-knee cast twice within a 2 year span during high school and her later teens. She still has symptomatology and developed not only nonunion but sclerosis and cystic changes.
This is the previous patient’s described CT scan and again you see the nonunion and a cystic changes. They are reverent and that essentially what happen these type of injury that are completely fractures. If they are not treated with surgical reduction and bone graft they end up nonunited or fibrous union and then they refracture and often can develop degenerative changes at the talonavicular or even cuneonavicular joints.
In 2000, we describe the surgical treatment and the results of _______ navicular stress fractures. Typical incision is lateral to the neurovascular bundle and the screw is usually placed from lateral to medial. In fact, this drawing depicts it incorrectly, the screw head should be oriented lateral and the screw shaft is driven towards the navicular tuberosity. Often bone graft is needed, the patients need to be nonweightbearing for 6 weeks postoperatively and below knee cast boot for additional 4-6 weeks.
This is the patient that had ORIF of the navicular with autogenous calcaneal bone graft. Screws rarely need to be removed.
This is another patient that had ORIF for complete navicular fracture with autogenous bone graft in a 4.0 screw. Again the screws oriented from lateral-to-medial.
This is another example of a type II or incomplete navicular stress fracture with sclerosis or an S type and again the CT scan is imperative that showing the amount of fracture and the severity. MRI is not helpful at determining the fracture pattern and severity.
Navicular stress fracture, ORIF. Again the incisions lateral to the neurovascular bundle and screw is oriented from lateral-to-medial. The patient is kept nonweightbearing for 6 weeks in the below-knee cast for cast boot and the cast boot till 10 to 12 weeks postoperatively. It is very helpful to get the exact fracture pattern with a CT scan utilizing 1.5 mm axial cuts.
This is an example of the patient undergoing ORIF for navicular stress fracture at type IIS, shows the incision on the dorsum of the foot again lateral to neurovascular bundle, which is palpated prior to inflation of tourniquet. Usually tourniquet is not inflated until dissection is carried down through periosteal region then the tourniquet can be inflated. The fracture was exposed and able to turn this based on the CT scan. Usually the fracture propagates from the high point of navicular.
Again a 4.0 screw is oriented from lateral-to-medial. The ___ can be placed first and finger palpate in navicular tuberosity, essentially aiming for the navicular tuberosity. Tip of the screw length is 26 mm to 34 mm and the screw size is partially threaded 4.0 mm screw. Bone graft is attempt in the place prior to final compression.
Bone graft is taken from the lateral aspect of the calcaneus, cortical window can be maintained and placed back into the region after the bone graft is harvested. We like to use autologous bone, not cadaveric bone, because of the lack of osteogenic potential. Bone stimulation has been found to be somewhat helpful in these type injuries as well.
Sometime it is difficult to assess the healing with radiographic studies. CT scan often can show false negatives. Tomogram actually is quite helpful. We also just base of this on clinic signs and symptoms including lack of pain and palpation on the area, lack of pain with activity.
Again the article that we published was in journal Foot and Ankle Surgery 2000, I highly recommend to read that because there are very little articles published on navicular injuries. As far as case series and case studies, there are very few that are even close to this largest series. The paper we published was largest in the United States. I have also collected additional data on more patients and look forward to publishing a future paper.
The additional data includes 9 more surgeries. Again this involves primarily type II and type III or the more severe fractures. We feel that the type I injures usually are treated successfully with nonoperative treatment. However, the type II and III injuries usually necessitate surgical treatment with bone grafting.
I will talk about stress fractures in the leg, fibular stress fractures are quite common, seem to be more common in females. This bone scan shows a midshaft fibular stress fracture and these are often treated with air cast type of leg braces and protection for 6 weeks. The braces can be maintained while they continue the sports for the next several weeks.
The type of leg pain is tibial periostitis. Supposedly this is a precursative development stress fracture. Believe it or not it was found to be always the case. Bone scan will have diffused uptake. It is supposed with a localized uptake with a stress fracture. Also, keep in mind, the stress fractures usually are locally tender as swelling, throbbing, and the pain increases with activity. With periostitis, the pain does not necessarily increase activity, in fact often it gets better. After activity, they will have diffused tenderness. We treat this symptomatically with an air cast and also evaluation of the foot type for consideration of foot orthoses.
Medial malleolar stress fractures are notoriously slow in healing. They can be picked up from bone scan, often difficult to see on plain x-ray. These have a pedal action for slow healing. In fact, all I have talked about his case studies for 5 months or more for return to activity. We use to keep the patients nonweightbearing for at least 3 to 6 weeks and could consider an ORIF to get the patients back to activities including sports sooner. Usually, it takes at least 6-12 weeks with the period of nonweightbearing and a below-knee cast or air cast type of brace.
Distal tibial metaphyseal stress fractures often have a fairly successful healing course if the patients are kept nonweightbearing. This x-ray shows the sclerosis 4 weeks later. We treat this with nonweightbearing and an air cast for at least 4 to 6 weeks.
Medial tibial stress fractures of the classic posterior medial tibial shin pain, you know always need a bone scan or MRI to depict radiographic changes. John Durkin has described an external oblique view of the leg, which you can see the posterior medial tibial crest that exposes any periosteal bone inflammation, which is helpful in diagnosing stress fractures. The various bowing of the legs are also critical and apparently implicated in development of stress fractures. Because of the tibial bending or bowing, there will be more compression and pedal action for stress fractures with a varus tibia. These are often treated with long leg air casts for at least 6 weeks. Often, this takes at least 6 to 12 weeks to allow the patient to return to sports. Again, we can evaluate the foot type and consider foot orthoses as well.
Medial tibial stress fractures occur with overuse and stress injuries. The successful treatment includes an early foot orthoses, with lower extremity strengthening and long leg or air cast type of functional bracing.
Anterior tibial stress fractures are very difficult situations for patients and athletes. The dreaded black line which shows essentially a non-united anterior cortex is a bad sign. This often means that these patients will necessitate electronic bone stimulation and prolonged immobilization. This delayed union is not uncommon and these injuries usually takes 6 or more months to heal. Clanton even recommended surgery, which included bone grafting and possibility of an intermedullary nail. Again, these injuries can take more than a half a year to recover from.
The stress fractures of the lower leg were mentioned in the air cast type of leg braces. They make a long leg variety, and for anterior tibial stress fractures, they have an anterior panel. This anterior panel fits between the two medial and lateral stirrups. Pneumatic leg brace functions to deviate the leg and take the stress off the leg bones and very helpful for tibial and fibular injuries.
CONCLUSION: There are many types of stress fractures below the knee that are commonly encountered by podiatrists, particularly those in treating athletic patients. There is not a lot of literature on successful treatment other than rest and immobilization. Further studies needed to see if other items such as foot orthoses, surgery, pulse electronic magnetic fields and bracing are all significant. But I believe that they are all part of the treatment for these various different injuries and I encourage further research and reading in this region. Thank you.