TABLE 1: STRESS FRACTURE RISK FACTORS: POSSIBLE MECHANISMS AND INTERRELATIONSHIPS

Risk factor Training

Variables

n Type n Volume n Intensity n Surface n Changes in training

Footwear Figure 5: MRI scan showing bone

marrow oedema and fracture line of the navicular

periosteal, muscle, or bone marrow oedema with or without an actual fracture line (fig 5). A positive bone scan or MRI scan

can be followed up by a CT scan to differentiate between a stress fracture and a stress reaction (1), and will demonstrate the precise position and severity of the fracture (fig 6).

Risk factors

Along with the history, risk factors that can be detected on physical examination should be identified (table 1) and modified to reduce the load applied to the bone in question.

Classification

Stress fractures should be classified as either high or low risk based on the fracture location as this determines the predominant mode of loading i.e. tension or compression. Fractures that are predominantly loaded in tension are high risk and often have a poor natural history compared with low risk stress fractures which are loaded in compression and have a much better natural history (12). For example the anterior tibia is under tension due to bowing and is a high risk fracture whereas the medial border is compressed and is a low risk fracture. The management approach differs between the two because in the former the risks and complications of non-union exceed those of aggressive treatment. Therefore depending on radiographic findings high risk stress fractures may require prompt operative management or a period of strict non-weight bearing, with close follow up and a monitored rehabilitation. High risk fractures need to have healed with a normal examination and painless functional activity before being released into full play. Table 2 lists the location of

24 Figure 6: CT scan demonstrating

precise position and severity of a navicular stress fracture

common lower limb high, medium and low risk stress fractures.

MANAGEMENT Treatment is determined by the fracture site, the length of symptoms and the severity of the lesion. The vast majority of stress fractures have a brief history and can be treated non-operatively without complication by avoiding stressing activity and grading the return to training over a 4-8 week period (12, 13).

TIP: Surgical treatment is only recommended for delayed union, failed conservative management or high risk problematic fracture sites which require additional treatment (Table 3).

Treatment can be divided into two

different phases; modification of activity in phase 1 and a graded reintroduction in phase 2 (3, 11).

Phase 1

As soon as a stress fracture is suspected the player must be removed from training and rested from the aggravating activity which is the cornerstone of treatment. Pain relief is an early priority best controlled with simple analgesics and ice as it

n Type n Age of shoe n Use of insoles

Lower limb alignment n Foot type n Tibial torsion n Knee varus/valgus n Femoral anteversion n Leg length

Muscle function

Muscle length and joint range

Menstrual status

n Strength n Endurance (particularly calf muscles)

n Flexibility of calf, hamstrings, hip flexors

n Range of ankle dorsiflexion, hip internal/external rotation

n Current and past menstrual patterns

n Use of the oral contraceptive pill

n Sex hormone levels if irregular

Bone density – dual

energy x-ray absorptiometry (DXA)

Dietary intake

n If amenorrheic or multiple stress fracture history

n Calcium n Energy n Other nutrients influencing absorption of calcium or bone health e.g. protein, fibre n Presence of eating disorder

is seldom severe (11). NSAIDs are to be avoided as there is speculation that they hinder the repair process (3). If the player is experiencing pain

TABLE 2: CLASSIFICATION OF CRITICAL AND LESS CRITICAL STRESS FRACTURES High risk

Femoral neck

Anterior mid tibia Navicular

Body of the talus

Proximal 2nd metatarsal Sesamoids

Pars interarticularis sportEX medicine 2010;43(Jan):22-27

Medium risk Femoral shaft

Posterior or medial tibia Medial malleolus

Proximal 5th metatarsals

Less risk Fibula

Lateral malleolus Calcaneus Cuboid

Cuneiform Distal metatarsals, 2,3,4, and 5