Stress fracture describes either a partial or complete fracture of the bone. There are two types of stress fractures:
Fatigue fracture represents up to 20% of all sports-related injuries. Due to the mechanism of this injury, stress fractures are more commonly found in weight-bearing limbs such as your tibia (shin bone), metatarsals (foot) and fibula (next to your shin bone). The location of stress fracture also varies by the type of sports you do. For example, track athletes typically get stress fractures in the foot/ shin.
Insufficiency fractures can occur in any bone with abnormal bone mineral density (BMD).
Today, we will talk about what bone is made of, how stress fracture occurs in sports and management approach and return to play.
Figure 1. Bone with multi-layers (compact and cancellous bone)
Bones and fractures
Your bones are made up of connective tissue in multiple layers (refer to figure 1). These connective tissues are reinforced with calcium and specialised bone cells. Your body is in constant homeostasis between microcrack creation and repair, meaning that the bone cells are constantly remodeling the skeleton by building up new bone tissue (osteoblast cells) and breaking down old ones (osteoclast cells) as required.
Crack initiation – typically occurs at the site of stress concentration during bone loading
Crack propagation – when abnormal force continued to apply to the bone, disrupting the homeostasis at which the rate of new bone laying down and microcracks repair is below the rate of stress applied
Complete fracture – when continued and increased load is not met with increased reparative process reaching a point of structural failure and partial and complete fractures occur.
In a sports setting, fatigue fracture is often seen as a gradual onset of pain without any traumatic events. It is common especially with a recent increase in training intensity or volume and inadequate resting period. The overall pain level can progress from training only to affecting activities of daily living. The pain usually eases with rest and cessation of aggravating activities.
Insufficiency fracture is typically due to abnormal bone health. Healthy bone needs a balanced diet and regular weight-bearing exercise to maintain its density and strength. Thus, people who is affected by eating disorder, thyroid dysfunction may experience increased difficulty to retain a good BMD. BMD is a measure of the amount of minerals (calcium and phosphorous) contained in a certain volume of bone. Generally, BMD peaks roughly at age 25 and is maintained throughout the middle age of 35. Then it depletes gradually by 0.3-0.5% per year as part of the aging process.
Estrogen is important in maintaining BMD in women, thus, amenorrhea and post-menopausal women often experience increased risk of osteoporosis. BMD can deplete up to 2 to 4% yearly.
When bone density decreases past a certain level, a person is more likely to suffer osteopenia and osteoporosis. Osteopenia is when bone density is below the average for your age group. On the other hand, osteoporosis is a more severe case of bone loss that weakens the bones and increase the risk of fractures. Thus, people who suffer from osteopenia or osteoporosis are more prone to insufficiency fractures. A common example of this is a person fractured his / her foot from simply hopping off the bus.
Diagnosis
Physiotherapists can generally provide a provisional diagnosis based on your history and mechanism of injury. It is not until the condition has worsened over time that further investigation is carried out. Further investigation can include X-ray, bone scan, MRI and CT scan to confirm the diagnosis. Radiological imaging can be vital in determining whether a surgical approach is required in cases where healing is impaired and non-union is present.
Early physio management
The majority of stress fractures can be conservatively managed, incorporating 6-8 weeks of rest, depending on severity.
Your physio may ask you to modify, reduce or cease the activities or training you're currently doing during this period. Depending on severity, weight-bearing may also need to be reduced, protected or completely stopped in the worst case scenario.
Your physio may also give you extra padding or orthotics to deload the stress on the painful body part (e.g. CAM or moon boot).
If pain subsided after 6-8 weeks period, it is generally advisable to gradually ease into your training program in terms of load, intensity and volume. A sudden increase in these parameters can aggravate your stress fracture if not implemented gradually.
Below are the common types of stress fractures and some general management approaches.
Return to training / sports
After you are cleared of stress fracture and symptoms have subsided, your physio will recommend to gradually ease into your training program in terms of load, intensity and volume.
Periodisation in your program becomes useful here as you are likely to focus on control and strength early on, with progressive loading from using light to heavier weights. Then after 4-6 weeks, rehabilitation can start to include power and dynamic balance.
If pain persists after 6-8 weeks, it is advisable for you to seek help from a doctor for further investigation and consider further imaging to determine whether surgical intervention is required.
Suspect you may have a stress fracture? We'd be happy to help. Book online or call us on 3061 7128.