Monday, May 01, 2006

Fractures and soccer boots: over use or poor design ?

The latest soccer player to fall foul of a metatarsal fracture is Wayne Rooney who has notched up his second fracture on his right foot. The star striker is likely to miss the beginning of the FIFA World Cup Germany 2006. Of all the small bones in the bone the metatarsals are quite difficult to break despite this quite an impressive list of soccer elite have done so in the last few years. The list includes David Beckham, Michael Owen, Steven Gerrard, Danny Murphy and Scott Parker. This has led to much speculation about the absence of protection afforded to the small bones by the current boot design which concentrates upon lightness and grip. Despite calls to return to the good old days (or was it the bad old days?) with heavier footwear because to the uninitiated fractures of the metatarsals were less frequently reported is almost certainly ill founded. The current style of soccer slipper is probably the epitome of the sport shoe which allows the elite athlete to compete at optimal efficiency. However one problem with this technological match of man and boot is the oppressive desire by clubs to train and play the athlete until burnout.
The cause of metatarsal fractures vary but overwhelmingly fractures of the middle metatarsals (i.e. 2,3 and 4) relate to fatigue caused by longitudinal rotation in the midfoot as the heel swings between supination and pronation. This action is perfectly normal but when repeated incessantly creates the potential for a hair line fracture. During the Second World War the condition was described as a March fractures and reported in epidemic proportion in new recruits undergoing based training which involved “square bashing” (repeated marching on hard ungiving surfaces). Many novice players will experience this and it reponds to rest. When elite athletes are reporting fatigue fractures this indicates gross overuse and unlike a hair line crack can present as a full fracture or if compounded with an impact injury a compound fracture (more rarely reported). Repeated incidents of metatarsal fractures are consistent with weakness in the small bone to cope with prolonged longitudinal rotation of the midfoot. Fractures of the lateral (5th) metatarsal have more to do with over pull of the peronei muscles from the lateral column of the leg. The foot is controlled by a stirrup action controlled by the interaction between the tibialis anterior muscle which is inserted in the medial side of the foot and the peroneii which are inserted into the lateral column. Violent overpull of the peronei brevis muscle can cause the base of the fifth metatarsal to detach and this is the type of fracture reported in the case of Michael Owen. Wood’s fracture can be caused by going over on the ankle or when the foot is aggressively twisted as might arise when the foot is off the ground and the player is poised to control the ball with a twisted foot and just at the critical moment the foot is traumatized by contact with the ground or the boot of another player. Failing that event over use and fatigues can predispose to Wood’s fractures and no boot design can prevent these events. Fractures of the large metatarsal are relatively rare and commonly caused by serendipitous trauma. Longitudinal rotation of the large metatarsal caused by the foot adjusting to the ground surface will frequently show on the distal end at the metatarsal head presenting as sesamoiditis (inflammation of the sesamoids) or more likely osteoarthritis of the big toe joint. This is the most common foot injury of football players. So the dilemma which faces the English squad again has more to do with accumulated abuse of key players in their club training and playing schedules than deficits in boot design.

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