The “ banana foot”

So, you see at foot that looks like this and what do you think? What are some of the biomechanical characteristics of people with the foot that when, you bisect the calcaneus, the line passing forward passes lateral to the second metatarsal or a line between the second and third?

This condition can be congenital, in conditions like forefoot adductus or compensatory.

The first thing that springs to mind when we see deformities like this is “things usually occur in threes“. So we would expect to see other anatomical and/or genetic abnormalities. An adducted forefoot, like you see here, often occurs as the result of lack of internal rotation of the hip on that side so therefore will often be present with conditions like internal tibial torsion and femoral retrotorsion, which we often, but not always, see together. Because of the increased gait and foot progression angle in these individuals, the forefoot compensates and adducts to bring the center of gravity more to midline.

Feet like this are often, but not always, cavus and rigid. If it remains in relative supination (plantarflexion, abduction and inversion) it is an excellent level but poor shock absorber.

Forefoot adduction can also be a compensation pattern if an individual is unable to get the head of their first ray completely down to the ground. It could be a true forefoot varus or more commonly, a forefoot supinatus; either results in an inability to get the first ray down. This often causes the foot to adduct in compensation, and, due to the tarsal articulations, often raises the base of the first metatarsal increasing the inclination angle of the first ray. This frequently leads to limited dorsiflexion of the first metatarsophalangeal articulation.

So what is a clinician to do?

Ensure that the mechanics of the foot are clean through manipulation and mobilization

Make sure there are appropriate flexors/extensor ratios of skill, endurance, and strength of the foot musculature both intrinsically and extrinsically. This means making sure that the long flexors and extensors are in some degree of balance.

Work on balance and coordination of the lower extremity. This can be impeded if they’re unable to get ahead of the first right down to the ground. Exercises for the peroneus longus, extensor hallucis brevis and short flexors of the foot will often help with this.

“Banana foot”. Coming to your clinic, or a clinic near you. Maybe today…

Dr. Ivo Waerlop, one of The Gait Guys.

#forefootadductus #bananafoot #supination #thegaitguys

Asymmetries can make all the difference…

Take a good look at these pictures of this gentleman’s feet. Can you see any differences from side to side?

If you look closely, you’ll notice that his right foot is in and abducted position (4 foot adductus) and relatively normal. Asymmetries can make all the difference…

Take a good look at these pictures of this gentleman‘s feet. Can you see any differences from side to side?

If you look closely, you will notice that his right foot is in an adducted position (forefoot adductus) and the left one relatively normal. If you bisect the heel, it should pass through the second or between the second and third metatarsal in his clearly falls laterally.

So what you say?

Well, putting a foot in relative supination with respect to the other causes certain biomechanical sequela. This forefoot adductus often leads to a forefoot supinatus, so he’s unable to get the head of his first ray down to the ground. Think that might make a difference in his gait cycle?

Think about all the extra internal rotation that will have to occur in that lower extremity during a normal gait cycle. Now combine that with something like external tibial torsion or a leg length discrepancy and things can really stack up and make a big difference.

Lastly, think about the asymmetrical mechanoreceptor input from the joint mechanoreceptors and muscle spindles traveling up the neuraxis. Do you think over time that that may cause some cortical remodeling and ultimately change the way he activates muscles?

Look for asymmetries, they really do matter

Dr Ivo Waerlop, one of The Gait Guys

#asymmetriesmatter #gaitanalysis #thegaitguys #forefootadductus

Things seem to come in 3's...

Things tend to occur in threes. This includes congenital abnormalities. Take a look this gentleman who came in to see us with lower back pain.

Highlights with pictures below:

• bilateral femoral retrotorsion

• bilateral internal tibial torsion

• forefoot (metatarsus) adductus

So why LBP? Our theory is the lack of internal rotation of the lower extremities forces that motion to occur somewhere; the next mobile area just north is the lumbar spine, where there is limited rotation available, usually about 5 degrees.

Dr Ivo Waerlop, one of The Gait Guys.

#tibialtorsion #femoraltorsion #femoralretrotorsion #lowbackpain #thegaitguys #gaitproblem

this is his left hip in full internal rotation. note that he does go past zero.

full internal rotation of the right hip; note he does not go past zero

note the internal tibial torsion. a line dropped from the tibial tuberosity should go through the 2nd metatarsal or between the 2nd and 3rd.

ditto for the keft

a line bisecting the calcaneus should pass between the 2nd and 3rd metatarsal shafts. If talar tosion was present, the rearfoot would appear more adducted

less adductus but still present

look at that long flexor response in compensation. What can you say about the quadratus plantae? NO bueno…

Ditto!

Metatarsus Adductus: The Basics

Metatarsus Adductus: The Basics

A few points to remember:

• Metatarsus adductus deformity is a forefoot which is adducted in the transverse plane with the apex of the deformity at LisFranc’s (tarso-metatarsal) joint. The fifth metatarsal base will be prominent and the lateral border of the foot which is convex in shape . The medial foot border is concave with a deep vertical skin crease located at the first metatarso cuneiform joint level. The hallux (great toe) may be widely separated from the second digit and the lesser digits will usually be adducted at their bases (se below). ln some cases the abductor hallucis tendon may be palpably taut just proximal to its insertion into the inferomedial aspect of the proximal phalanx (1)
• To measure the deviation of the metatarsals, the midline of the foot correspondingto bisecting the heel is used as a reference. This is the line that divides the heel pad into equal parts and, when extended, runs through the second toe or the second web space. In mild deformities, the midline of the foot runs through the third toe. In moderate adductus deformities, it falls between the third and fourth toes. In severe deformities the line is lateral to the third web space.(2)
• If detected early, stretching is a common and effective treatment for mild and some moderate cases. The heel is steadied with one hand while the forefoot is abducted in relation to the hind foot. This is done for 5 reps, 5-7 times per day. (2)
• 85% will resolve spontaneously, is caused by intrauterine position, is flexible & resolves spontaneously in more than 90 % of children. (3)
• Though often used interchangeably, the term "metatarsus adductus" is usually reserved for milder cases, where the forefoot is adducted on the hindfoot at the tarso-metatarsal articulation. Metatarsus varus is often reserved for conditions where the matatrsals are actually curved AND the forefoot is adducted on the hindfoot. (4) The term "Metatarsus primus varus" is reserved for feet which have the same neutral or valgus hindfoot and varus forefoot but, in addition, increased divergence of the first and second metatarsals. (5)
• It is interesting to note that along with forefoot adductus, hip dysplasia and internal tibial torsion are common (6) and this patient has the latter
• Gait abnormalities seen with this deformity include a decreased progression angle, in toed gait, excessive supination of the feet with low gear push off from the lesser metatarsals. 

1.  Bleck E: Metatarsus adductus: classification and relationship to outcomes of treatment. J Pediatric Orthop 3:2-9,1983.

2. Bohne W. Metatarsus adductus. Bulletin of the New York Academy of Medicine. 1987;63(9):835-838.  link to FREE full text: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1629274/

3. http://www.wheelessonline.com/ortho/metatarsus_adductus

4. Peabody, C.W. and Muro, F.: Congenital metatarsus varus. J. Bone Joint Surg. 15:171-89, 1933.

5. Truslow, W.: Metatarsus primus varus or hallux valgus? J. Bone Joint Surg.23:98-108, 1925.

6. Jacobs J: Metatarsus varus and hip dysplasia. C/inO rth o p 16:203-212, 1960

additional references:

Kane R. Metatarsus varus. Bulletin of the New York Academy of Medicine. 1987;63(9):828-834. link to FREE full text: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1629282/

Wynne-Davies R, Littlejohn A, Gormley J. Aetiology and interrelationship of some common skeletal deformities. (Talipes equinovarus and calcaneovalgus, metatarsus varus, congenital dislocation of the hip, and infantile idiopathic scoliosis). Journal of Medical Genetics. 1982;19(5):321-328. link to FREE full text: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1048914/