![]() The damage accumulates through cyclic loading when bone remodelling is given insufficient time to repair damage from loading (Warden et al., 2006). ![]() The pathological continuum of navicular stress fractures begins when the ‘microdamage’ exceeds the bone’s threshold (Bennell, Malcolm, Wark, et al., 1996). However, repetitive stress associated with failed bone remodelling can begin the pathological process resulting in stress reaction, stress fracture and subsequent complete fracture of the navicular (McCormick et al., 2011 Warden et al., 2006). Whilst, this is defined as the initial stage of the stress fracture continuum, no current evidence suggests intervention is required as bone has the ability to remodel and repair (Warden et al., 2006). Repetitive stress of a bone is naturally associated with ‘microdamage’ and is a normal phenomenon in humans (Bennell, Malcolm, Wark, & Brukner, 1996 Warden et al., 2006). Through repetitive bouts of mechanical load, potential for bone strain occurs (Warden, Burr, & Brukner, 2006). As a consequence, the maximum shear stresses are exerted through the central third of the navicular body (Gross & Nunley, 2014 Mann & Pedowitz, 2009). During foot-strike initially the navicular accepts force from first and second metatarsocuneiform joints, then medially sharing force with the talar head and finally lateral forces from the second metatarsal and middle cuneiform (Gross & Nunley, 2014). The navicular bone is anatomically located in a unique position that exposes it to various forces and an unusual vascular supply, leaving it vulnerable to overuse injury (Jones & Amendola, 2006 Mann & Pedowitz, 2009). However, we now know navicular stress fractures are one of the most common stress fracture sites in the body (Mann & Pedowitz, 2009), with evidence suggesting they comprise 14% to 25% of all stress fractures (Bennell, Malcolm, Thomas, Wark, & Brukner, 1996 Brukner, Bradshaw, Khan, White, & Crossley, 1996). Navicular stress fractures were first described by Towne and colleagues in 1970 and initially were thought to be rare (Jones & Amendola, 2006). As a result, patients presenting with this injury are classically running athletes (Gross & Nunley, 2014), with one study demonstrating 59% of navicular stress fractures are track and field athletes (Brukner et al., 1996). Navicular stress fractures are an overuse injury characterized by tenderness over the navicular bone which usually results from repetitive impact loading causing a reduction in its load-absorbing properties. ![]() It's awesome to have other like-minded clinicians put time into sharing their knowledge with others and contributing to Rayner & Smale. Recently Josh has been learning about navicular stress fractures, and for this blog, he shares his new knowledge about the causes, risk factors, pathophysiology and management of this condition. Teaching is another great passion of his and in the future Josh's hope is to help educate the next generation of clinicians. Over the past few years Josh has developed a great interest in spinal pathologies, particularly non-specific neck pain and is planning to one day further research for physiotherapists in this area. In 2015, Josh completed the graduate certificate of musculoskeletal physiotherapy at La Trobe University and is currently undertaking the masters program at La Trobe. Josh completed his undergraduate degree at Monash University in 2012 and has since been practicing at Physica. ![]() This week we are joined by Josh Farragher, Physiotherapist at Physica Spinal and Physiotherapy Clinic in Melbourne, Australia.
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