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27 y/o triathlete who competed in a duathlon 5/52 ago. the following day symptoms of pain on weightbearing and localised swelling and bruising at proximal end of 5th metatarsal left foot. Sports physician used bone scan proved negative for stress fracture, however "little bit of extra metabolism in the periosteum". Initially, pain after heel lift, and when pushing off wall (swimming), No pain now as not running. Wears Nike "gel cushion" (only 8/12 before injury) but thinking of switching back to Asics, her normal footwear of choice. Any general recommendations for biomechanical interventions please.
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Hi Mark

I would suggest you increase the lateral arch of the device.

It could be the peroneus brevis is working too hard and causing boney stress.

Also get the patient to look at their cycle biomechanics especially the position of the knees. I get a lateral 5th met pain when out cycling and my knees are not tracking properly also get the patient to check the saddle height if too high can lead to similar pains

__________________
Mike Weber.



Crazy Mary

Have you thought of using Ethyl Chloride and manipulating the soft tissue as you would a sprained ankle?

Mark:

There are a few structures that commonly become injured at the proximal 5th metatarsal base in runners. First of all, the peroneus brevis tendon is commonly injured at it's insertion site onto the styloid process and this injury is caused by excessive external subtalar joint (STJ) supination moments. The most likely mechanism is that the central nervous system (CNS) senses excessive external STJ supination moments and then, with increased efferent activity to the peroneus brevis and peroneus longus, causes increased contractile activity of the peroneals to increase the internal STJ pronation moments to prevent an inversion ankle sprain and/or STJ inversion instability. Using valgus rearfoot and forefoot wedge works quite nicely for these injuries with the goal being to move the center of pressure more laterally and increase the external STJ pronation moments. You could try a lateral heel skive in the heel cup of the orthosis and add extra filler plantar to the lateral longitudinal arch of the existing orthosis to stiffen the lateral longitudinal arch of the orthosis. You will definitely want to add a valgus forefoot extension to the orthosis, to the sulcus, since the 4th and 5th metatarsal heads have the longest STJ pronation moment arms of any other significant plantar weightbearing structures of the foot.

The bone scan result of "increased metabolism" or, as most of us would say, "increased uptake" may however indicate a stress-reaction (i.e. pre-stress fracture) of the 5th metatarsal base. Stress reactions of the long bones of the foot and lower extremity will be much more clear on an MRI scan where increased bone marrow edema (i.e. increased water content of the bone marrow) will be noted indicating an impending stress fracture. This condition is caused by increased bending moments at the 5th metatarsal proximal shaft and can also be successfully treated by the orthosis adjustments noted above but with more attention directed toward supporting firmly plantar to the proximal 5th metatarsal shaft to stiffen the lateral longtiduninal arch of the orthosis and decrease the 5th metatarsal bending moments.

The other injury in the area of the styloid process that can occur in runners, and which is much less common, is what I call "lateral plantar fasciitis" where the lateral component of the plantar aponeurosis can become inflamed at its insertion into the plantar base of the 5th metatarsal. The lateral component of the plantar aponeurosis is present in only about 75% of the population (if my memory serves me correctly) but it can very inflamed, especially in marathoners and ultramarathoners. Using an orthosis with firm lateral support under the lateral arch, icing and cortisone injections generally work nicely for these patients.

It is valuable to know your anatomy and how to palpate/muscle test for each of these injuries since this will help make you a much more valuable clinician for your runner-patients.

Hope this helps.

__________________
Sincerely,

Kevin

**************************************************
Kevin A. Kirby, DPM
Adjunct Associate Professor
Department of Applied Biomechanics
California School of Podiatric Medicine at Samuel Merritt College

e-mail: kevinakirby@comcast.net

Private Practice:
107 Scripps Drive, Suite 200
Sacramento, CA 95825 USA
My location

Voice: (916) 925-8111 Fax: (916) 925-8136
**************************************************

Thanks Michael, mgeiger?, and Kevin for replying.
Kevin, having read your posts (and messrs Spooner, Fuller and some great other contributions) for 4-5 years now, I was thinking along those recommendations already, but the "sports physician" had prescribed OTC 'gel' insoles so I wanted a bit of reassurance before I gave this young lady, a physiotherapist whom I work with, any advice. I have informed her of your input (letting her know how valued your opinion is).
Thanks again, mark

In addition to Kevin's and Michael's comments (Which were very similar in advice, but very different in format.) I would like to add check the location of the STJ axis and the amount of eversion available in static stance. A laterally deivated axis would theoretically cause more peroneus brevis pull. A lack of eversion available, also known as a rearfoot or forefoot varus, would cause increased bending moments. Also look at the sock liner of the shoe. Is there a greater impression under the 1st met and hallux from peroneal activity or is there a worn area under the styloid from lack of eversion?

Cheers,

Eric

A discussion with the pt regarding foot strike as well. I think a lot of tri coaches are really encouraging forefoot strike patterns, and when not a natural action, and fatigue towards the end of race, will increase eccentric activity through p. brevis.

Could this also be caused by excessive/prolonged pronation - in turn not allowing a proper recovery period for overworking peroneals?