Principles in Foot and Ankle Pathology
Which concepts give you the best frame of reference for understanding foot and ankle pathology?
Inversion vs Eversion
Varus vs Valgus
Flat foot vs Cavus Foot
Order of Correction
Muscle Balance
Soft Tissue Management
Rockers
Bony procedures
Osteotomy vs Arthrodesis
Gastrocnemius recesion
1 Inversion vs Eversion (subtalar motion)
The subtalar Joint has a
complex 3D movement. It represents the movement of the Talus above the calcaneus and the Midfoot rotating around the head of the talus (Acetabulum Pedis)
Thinking about this complex anatomy serve us to understand how the foot changes from a solid structure when the 3erd rocker arrives (to better initiate the propulsion of the body) and being loose and adaptable to the ground when the foot is first contacting with the grownd
2 Varus vs Valgus
Varus and Valgus Hindfoot are asociated with different pathologies, Varus feet are very common but a few degrees are badly tolerated. Varus locks the subtalar joint in supination and makes a rigid foot that is not able to adapt to irregularities in the terrain.
Valgus flatfoot are better tolerated but associated with medial arch colapse in extreme cases. 5º of valgus is considered normal in the hindfoot view
Exploring the flexibility of the foot is another important step in the systematic exploration of the foot (single heel rise and Fonseca test need to be explored in every flatfoot and coleman’s block test need to be performed in every cavus varus foot)
There are rare cases of Varus hindfoot + pes planus, as is in the Muller weis syndrome. (But that is a talk for another time)
3 Flat foot vs Cavus Foot
PesPlanus are associated with Hallux Valgus, hallux Rigidus, Tibial posterior tendinopathy, sinus tarsi impingment, deltoid ligament and spring ligament ruptures, and subperoneal impingment.
CavoVarus feets (pronated) are associated with rigidity, ankle instability, peroneal tendonitis, lateral ligament sprains, metatarsalgia, claw toes, and dificulty when traversing irregular terrain.
4 Surgical Order of Correction
First Correct Hip > Knee > Ankle
Hindfoot > Midfoot > Forefoot
Many of the common problems associated with insatisfaction in patients with otherwise technically correct surgery may be attributed to malalignment of the extremity proximal to the Foot.
For complex deformities like Genu Valgus + cavus foot, it is better to correct first the knee rather than the ankle, so no problems arise down the line
Moreover, operating the a complex deformated foot like a Neurologic Cavus varus deformity needs to be planned and operated following the order of PROXIMAL to DISTAL
Correct Equinus deformity
Achilles lengthening
Posterior Capsulotomy
Correct Rearfoot Varus/Valgus
Correct Midfoot Deformity
Abduction / Adduction
Supination / pronation
Correct Forefoot
Flexed or extended first ray
Correct Toes
Claw toes
5 Muscle Balance
There are Muscles that oppose each other, knowledge of the anatomy and function may help in the treatment of some of the conditions
For example in Charcot-Marie-Tooth (CMT) there is an hyperactivation of Peroneus longus (Flexed 1st Ray) and a weak peroneus brevis (loss of eversion)
That is the cause of the Cavus (first ray plantarflexed) and Inverted foot. It also informs us of what tendons need to be transfered where to substitute a deficient function.
6 Soft Tissue Management
The foot is a bony structure with little to no fat and soft tissue coverage. The vascularization is really tenuous as the majority of the arteries are terminal with little anastomosis.
Being really careful with dissection, making only one plane and preserving the subcutaneous without much crushing will lead to better outcomes
In our patients there are many risk factors that worsen the prognosis such us:
older patients
smokers (Need to stop smoking at least in the months before and after surgery)
diabetics (HB1Ac needs to be ordered and followed as a sign of DM control)
atherothrombosis disease (Sometimes Vascular surgeons need to be contacted to evaluate a patient)
Thinking about angiosomes in every approach saves you from one of the most feared complications, wound infection and skin necrosis.
For example in Calcaneus surgery the classic “Extended Lateral L” approach has more wound complications than other (Sinus tarsi) even when done with the “No touch Technique”. Because it violates the principle of the Angiosome, leaving a triangle with deficient irrigation.
7 Rockers
First Rocker doesn’t have Metatarsalgia
Only Talalgia, a topic for another time.
Second Rocker is associated with Static metatarsalgia
Bony head Height problem
Circular circumscribed callosity
Under the Head
Look in the Lateral Xray or metatarsal view
Third Rocker is associated with propulsive metatarsalgia
Bony head length problem
Diffuse callosity
Distal to the head
XRay - weight bearing Dorsoplantar view - Look for Maestro’s Line
8 Bony procedures
In general, most neurologic foot and big deformities need to start with bony procedures because soft tissue procedures alone are not sufficient for correcting deformity and preventing relapses.
9 Osteotomy vs Arthrodesis (fusion)
As a rule of thumb, first you need to catalogue the foot that you are exploring in valgus or varus rearfoot and then you need to assess the mobility and rigidity of the subtalar joint and other neighbour joints. With those two pieces of information you you can decide if a osteotomy will be the better treatment (flexible nonrigid non arthritic joint) or a fusion (arthritic, rigid foot)
10 Gastrocnemius
Tight Gastrocnemius need to be diagnosed by exploring with the silfverskiold test
Tight heel cord is associated with equinus foot
It has been published in many articles the relationship between a multitude of foot and ankle pathologies with tight medial gastrocnemius. Doing a proximal lengthening of the medial gastrocnemius is a simple procedure that has great value in improving many conditions.
Eccentric exercise being done daily is associated with improvement in pain and gaining mobility and foot dorsiflexion (Example of exercises for plantar fasciitis)
Take Home Message
CavoVarus feets (pronated) are associated with rigidity, ankle instability, peroneal tendonitis, lateral ligament sprains, metatarsalgia, claw toes, and dificulty when traversing irregular terrain.
PesPlanus are associated with Hallux Valgus, hallux Rigidus, Tibial posterior tendinopathy, sinus tarsi impingment, deltoid ligament and spring ligament ruptures, and subperoneal impingment.
Read the callosities and Xray of the foot to understand which problem needs to be treated, longitud or height of the metatarsal head.
Bony procedures are the gold standard and soft tissue procedures are done as an associated technique
Rigid and arthritic foot requires fusion for best results
Always look for tight gastroc with silfverskiold test, prescribe eccentric exercise as the first line.
Quitting smoking and getting under control glycemic levels are associated with improvement in the rate of complications after surgery.
Bibliography
Schepers, T. The sinus tarsi approach in displaced intra-articular calcaneal fractures: a systematic review. International Orthopaedics (SICOT)35, 697–703 (2011). https://doi.org/10.1007/s00264-011-1223-9
Cortina RE, Morris BL, Vopat BG. Gastrocnemius Recession for Metatarsalgia. Foot Ankle Clin. 2018 Mar;23(1):57-68. doi: 10.1016/j.fcl.2017.09.006. PMID: 29362034.
Barouk P, Barouk LS. Clinical diagnosis of gastrocnemius tightness. Foot Ankle Clin. 2014 Dec;19(4):659-67. doi: 10.1016/j.fcl.2014.08.004. Epub 2014 Sep 26. PMID: 25456715.
Sman AD, Hackett D, Fiatarone Singh M, Fornusek C, Menezes MP, Burns J. Systematic review of exercise for Charcot-Marie-Tooth disease. J Peripher Nerv Syst. 2015 Dec;20(4):347-62. doi: 10.1111/jns.12116. PMID: 26010435.
Devos Bevernage B, Leemrijse T. Predictive value of radiographic measurements compared to clinical examination. Foot Ankle Int. 2008 Feb;29(2):142-9. doi: 10.3113/FAI.2008.0142. PMID: 18315968.
