First, it is important to reiterate that there is a lot of theoretical knowledge about lower extremity biomechanics, a great deal of information that is very academic and has little to no relevance to real life and, more importantly, biomechanical abnormalities that are encountered almost daily in our comprehensive healthcare clinics.
I am well aware that someone reading this book will list many areas that should be covered. With the purpose of this book in mind, I decided to primarily explore the clinical application of orthopedic therapy, discussing the prescription, evaluation, and treatment of a combination of ICB orthopedic inserts and supportive therapies. For my part, there is a great concern to start with the basics and make lower extremity biomechanics and orthopaedic therapy as easy to understand as possible. Therefore, we need to start at the beginning, unaware of the basic platform that supports the superstructure.
We all know that the foot consists of 26 bones and 2 seed bones (located below the first metatarsophalangeal joint), all of which work in concert to maintain the support and stability of the superstructure. If the base is unstable, then the entire structure will be affected and the soft tissues will usually try to “compensate” for the base abnormality. You will notice that the foot is triangular in shape and divided into 3 distinct parts: the hindfoot, midfoot and forefoot. The hindfoot consists of the heel bone and the talus, which together form the subtalar joint.
The midfoot consists of the cuneus, bone and navicular bone which lock together to support the weight of the entire body during mid-standing and when the center of gravity falls into this area.
Finally, the forefoot is composed of the phalanges and metatarsals (metatarsal bodies). As you can see from the diagram, the weight is distributed between the heel bone to the metatarsal body and the joints.
The body applies all of its weight in a load-bearing position on the navicular, cuneiform and dice bones (NCC), which become the cornerstones of the supporting structure.
Just as the medial structure is designed to be the “cornerstone” for supporting the arch indoors or outdoors, the NCC also supports the foot, creating a dynamic and strong base structure – this is the center of gravity (COG).
The most important joint in the foot is the subtalar joint, which is a three-plane joint that includes.
Plantarflexion and dorsiflexion are sagittal plane movements
adduction and abduction are transverse plane movements
Internal and external rotation are frontal plane movements
This element of triplanar motion is the basis for the use of orthopedic therapy, as both the anterior and posterior rotational elements arise around this concept.
Pre-rotation includes three movements.
1, abduction
2, dorsiflexion
3. valgus
Post-rotation consists of three movements.
1, abduction
2.Plantarflexion
3.Internal rotation
We seem to have discussed a lot about pronation because almost all pronation seems to be over-pronation, i.e., exceeding the acceptable 4-degree compensatory pronation angle needed to provide vibration absorption during the gait cycle. It is estimated that more than 80% of Western societies have problems with excess spin front.
However, Michaud 1997 states that either anterior or posterior rotation results in the same amount of inward or outward rotation of the tibial body, which in turn has a direct effect on the knee joint.
From my observations in the clinic, problems that occur in the hip usually affect the knee, and likewise the foot (base) affects the knee.
Usually we focus on the pain center, but do not link it to other causative factors. Let’s not only, just treat the pain, but also focus on the underlying factors that cause the pain. This is especially relevant when we look at non-trauma related pain.
As far as I know, anterior and posterior rotation will directly affect pain in the foot, leg and knee, and if the foot is over rotated anteriorly, this will cause the pelvis to tilt forward and cause pressure on the lower back area.
When evaluating a patient, special attention should be paid to the “location of pain” because medial and lateral collateral ligament knee pain can be directly related to excessive anterior or posterior rotation creating too much pressure and stretching these ligaments.
As mentioned earlier, bilateral anterior rotation will cause the pelvis to tilt forward, placing the lower back region in an anteriorly convex position and putting pressure on Ll- L5.
During forward rotation of the pelvis, this may become a contributing factor to vertebral slippage in the L5-S1 region. As the body activates compensatory mechanisms, tension may be felt in the thoracic region, creating a kyphotic curve where the rhomboids begin to tighten and the kidneys pull the body back to the center of gravity in an attempt to reduce the “bending effect” on the upper body. Can you understand that deeper “digging” is necessary in the diagnostic process and that these “domino” effects should be addressed in a comprehensive treatment plan using adjuncts.
The ICB concept is that we need to reduce the excessive movement around the subtalar joint and therefore reduce the negative structural effects of anterior or posterior rotation. The way we do this is to try to control the foot in a neutral position at the stagger angle and then use an ICB product (which limits but does not eliminate the 4 degrees of compensatory pronation), which would allow the foot structure to act as a body damper from mid-stance to toe-off phase.
I believe that the three primary locations in the foot proposed by Dr. Root and others do exist. Those are posterior rotation, anterior rotation, and neutral position (where the foot is neither anterior nor posteriorly rotated).
When the foot is rotated anteriorly, the talar bone is pronated, the sole is flexed (lowering the longitudinal arch), the navicular bone descends next to the dice bone, widening and lengthening the transverse distance of the foot tone BoTD II
Anterior view: when rotating forward the talus head and navicular talonavicular joint) joint, anterior heel bone joint to the dice bone (heel bone interdice bone joint. Note the low angle of the heel bone when rotating anteriorly i.e. <42 degrees, when rotating posteriorly, the talar head is abducted and dorsiflexed, the talar head exceeds the heel bone, compressing and shortening the foot structure. Anterior view: In posterior rotation, the talar head and navicular bone (giant navicular joint of the foot)
joint, anterior heel bone joint to dice bone (heel dice interosseous joint).
Note the high angle of the heel bone during posterior rotation i.e. >42 degrees
Note: The lateral distance increases and the vertical distance decreases when rotating forward. While in posterior rotation, the lateral distance (or foot width) is shortened and the vertical distance is increased.
So when the foot is in neutral position, the lateral and vertical distances are the same, which can be achieved before the foot hits the ground. We recognize that we cannot hold the foot rigidly in this position. What we are doing is eliminating the extra motion and limiting the negative effects of anterior and posterior rotation.
In “Biomechanical Examination of the Foot,” Vol. 1, 1971, Dr. Merton Root expressed the opinion that the “ideal” position of the subtalar joint is at an angle of approximately 420 to the transverse plane. If the heel angle is below 420, the foot is flat and in my experience, the following conditions are evident: cysts, plantar fasciitis, heel spurs, tarsal osteochondritis, metatarsalgia, Morton’s neuroma, internal shin splints, and medial knee pain.
Dr. Root also elaborated that a high arch will show a high inclination of the heel bone (over 420). I believe the following conditions can occur: high forefoot valgus, inversion sprain syndrome, external shin splints, lateral knee grip, lateral displacement of the fibular head, lateral hip pain, and due to the rigid nature of the foot, the patient will experience a lot of superstructural incongruity.
From 18 years of practice, I knew that placing the foot in the neutral position of the subtalar joint would be effective. Therefore, I have devised a simple and effective way to establish this neutral position that has been very useful in many situations, including.
1. placing a shaped orthotic insole in the patient’s shoe
2. performing plaster or foam box molding in order to establish a neutral position, measuring forefoot abnormalities in the patient’s supine position.
I developed this method in 1996, called the “anterior line method” (or “modified talar approach”) which was extended to counteract what I call “pseudo talar head syndrome” (the creation of a bony mass on the lateral aspect of the foot, making it difficult to determine the consistency of the talonavicular joint and the neutral position of the heel in stance). I have found the anterior approach to be very effective in finding neutral position and can be used in patients in a weight-bearing standing position, semi-weight-bearing or supine position.