Stress fractures are common in a sporting population, accounting for over 20% of all fractures in collegiate athletes [
1]. In cricket, fast bowlers are at risk of stress fractures of the pars interarticularis [
1,
2] related to incorrect technique, overuse, and poor preparation, but, to our knowledge, stress fracture of the clavicle has never been reported in cricketers.
Stress fracture of the clavicle has been reported, following radical neck dissection [
3], in a Catalan, human tower builder who had other team members standing on his shoulders [
4], and a 'cable-maker' who spent his day lifting a heavy drum on his shoulder whilst tightening bolts several hundred times a day [
5]. There are also reported cases in sports including a gymnast [
6], a diver using an open hand water entry technique [
7], a light weight sculler [
8], a baseball 3rd base man [
9], and a weight lifter [
10], but none from cricket.
A stress fracture is a fatigue failure of bone and, as such, can result from repeated unusual, unopposed or uncoordinated loading. It can be proposed that the unopposed action of muscles acting at the lateral clavicle following radical neck dissection predisposed this patient to stress fracture. Repetitive direct loading of the bone in the cable maker and the tower builder as well as the repetitive torsional loading experienced by the diver indicate the possible aetiology in these cases. In the other cases, there are multiple factors that may have resulted in bone failure, for example, the intensity and nature of training and issues with technique and execution of their sport's specific activity.
There are several factors that may have contributed to the development of this injury in our patient, notably the intensity of net training and the increased level of upper body gym work that he was undertaking. There was muscle imbalance around his shoulder girdle that was addressed during rehabilitation, and though technical issues with his bowling were not directly considered, he underwent formal technical analysis on returning to his team.
It is possible to propose a mechanism for the development of this injury. It possibly relates to the activity of the anterior deltoid and pectoralis major on the inferior aspect of the clavicle, counteracted by the action of the trapezius and sternocleidomastoid acting isometrically. This is the mechanism hypothesised to have caused this injury in the rower. Alternatively, it could be the strut effect of the clavicle supporting the shoulder being heavily axially loaded during the overhead phase of the bowling action when it is almost vertical. This could then result in a bending force, leading to eventual failure.