6) Tarsal Coalition Flashcards
Tarsal coalition
- Condition in which 2 or more bones in midfoot or rearfoot are joined (complete/incomplete osseous coalition)
- Fibrous/Cartilaginous coalition
- Patients usually present in adolescence with recurrent sprains, pain in midfoot with spastic for fixed flatfoot
Coalition proposed etiology (LeBouq)
- LeBouq’s theory of failure of differentiation of embryonic mesenchymal tissue
- Autosomal dominant inheritance
- First trimester insult
Coalition proposed etiology (Pfitzner)
- Pfitzner theory of ossification of accessory bones into adjacent tarsal bones
- Disproved by Harris finding coalitions in fetus
Acquired tarsal coalition etiologies
- Arthritis
- Infection
- Trauma
- Neoplasms
Congenital tarsal coalition
- Accessory ossicle incorporation
- Genetic mutation to an autosomal gene, resulting in failure of differentiation and segmentation of primitive mesenchyme
Coalition causes restriction or absence of
- Motion between two or more tarsal bones
- Can produce dramatic symptom complex, ultimately resulting in rigid peroneal spastic flatfoot
Tarsal coalition incidence
- 0.04% (24 cases in 60,000 young military personnel)
- 0.9% (11 in 1,232 children clinic)
- 1.4% (28 in 2,000 army personnel)
- On average < 1% of the general population
- 50-80% Bilateral
Tarsal coalition types/occurrence
- 90% Talocalcaneal (TC)
- Calcaneonavicular (CN)
- Talonavicular (3rd most common, <50 cases reported in literature)
- Calcaneocuboid
- Cubonavicular
- Naviculocuneiform
Tarsal coalition associated abnormalities
- Symphalangism (hands and feet)
- Metatarsal fusions
- Vertebral fusions
- Sacroiliac fusions
Tarsal coalition pathophysiology
- Normal STJ motion involves rotation and gliding
- During stance, STJ rotates from a position of 4 degrees external-valgus to 6 degrees of internal-varus
When the internal rotation is restricted by coalition, the tarsal joints have to compensate with
- Flattening of the foot and loss of longitudinal arch
- Leads to an adaptive shortening of the peroneal tendons, reactive peroneal spasm, and so-called peroneal spastic flatfoot
- Prolonged restriction of motion eventually may lead to posterior facet arthrosis of the subtalar joint
Subtalar joint gliding motion is lost during foot dorsiflexion.
Gliding motion replaced with hinge motion instead
- Widening at the plantar aspect of the midtarsal joints, narrowing at the dorsal surfaces, and overriding of the navicular on the talar head at maximum dorsiflexion
- Creating traction effect on the ligaments and capsule of the talonavicular joint resulting in talar beaking seen in many radiographs of tarsal coalitio
Pain symptoms associated with tarsal coalitions
- May therefore be attributed to ligament sprain, peroneal muscle spasm, sinus tarsi irritation, subtalar joint irritation, and arthritic changes
- The variability of the symptoms in different patients may be due to the variability of subtalar restriction of the different coalitions
Classification of tarsal coalition based on
- Etiology type
- Anatomic type
- Tissue type
- Articular involvement
Tachdjian’s classification
- Descriptive classification that suggest the importance of assessing other areas of the foot and the remainder of the body
Juvenile (osseous immaturity) articular classification system
- Type I - Extra-articular coalition
A- No secondary arthritis
B- Secondary arthritis
- Type II - Intra-articular coalition
A- No secondary arthritis
B- Secondary arthritisAdult (osseous maturity) articular classification system
- Type I - Extra-articular coalition
A- No secondary arthritis
B- Secondary arthritis
- Type II - Intra-articular coalition
A- No secondary arthritis
B- Secondary arthritisTypes of coalitions (osseous vs. non)
- Synostosis - osseous union
- Synchondrosis - cartilaginous union
- Syndesmosis - fibrous union
- Combo
Bars vs. bridges
- BARS = Extra-articular coalitions occur outside a normal joint
- BRIDGES = Intra-articular coalitions occurring at normal joint sites
Ossification/sympotmatic presentation
- Talonavicular 3-5 y/o
- Calcaneonavicular 8-12 y/o
- Talocalcaneal 12-16 y/o
- Pain secondary to mechanical stress arising from periosteum
Biomoechanical findings
- Middle facet talocalcaneal coalitions are associated with the greatest loss of subtalar motion and are the most likely to generate valgus
Heel-tip test
- Examiner supinates the foot of a standing patient by raising the medial border of the forefoot and keeping the heel and lateral border in contact with the floor
- In patients with limited or decreased subtalar motion, compensatory external tibial rotation is decreased, and the patella is not observed to rotate outward as in a person without tarsal coalition
Jack’s test
- Demonstrate the fixed nature of the pes planus and the loss of hindfoot inversion
- Also used for PTTD
Clinical findings
- Incidental finding on routine radiographs
- Onset of pain insidious, developing after trauma or unusual activity
- Pain aggravated by activity and relieved with rest
- Limitation of motion (subtalar and midtarsal), and muscle spasm
- Recurrent ankle sprains
- Sinus tarsi syndrome
Tonic muscle spasm (clinical finding)
- Rigid peroneal spastic flatfoot
- Biomechanical “splinting” of STJ
- Peroneus brevis attempting to restrict painful subtalar joint motion - subconscious effort
- NO neurological pathology (clonic spasticity)
Causes of peroneal spastic flatfoot
- Tarsal coalition
- Arthropathies
- Inflammation
- Infection
- Subchondral fractures
Conservative treatment
- Restriction of subtalar and midtarsal joint motion - shoe modifications, orthoses, padding, casting
- PT, NSAIDs, local steroid injections, prn
Surgical treatment
- Resection or fusion
Radiographic evaluation
- TALOCALCANEAL (middle facet) -LAT
- ”C” Signs – formed from the medial talar dome and posteroinferior border of the sustentaculum tali
- Bony bridge between the talar dome and sustentaculum tali, in combination with a prominent inferior border of the sustentaculum tali
Halo sign
- Middle facet coalition demonstrating radiographic sclerosis of the subtalar joint and the ‘‘halo’’ effect of spherical diffusion of ankle and hindfoot forces
Arthritic changes noted on radiographic evaluation
- Secondary arthritic or adaptive changes
- Functions of supination and pronation assumed by other joint, ie. Ball-and-socket ankle joint in talocalcaneal
Cross-sectional imaging
- CT
- MRI
- Reserved for cases in which radiographs are inconclusive
Talocalcaneal coalition
- Intra-articular coalitions traditionally considered indication for fusion
- Juvenile IIA, if small enough or if incomplete, may consider resection arthroplasty
- Wilde et al found that a valgus greater than 16º and a coalition surface area greater than 50% of the posterior facet on CT were predictors of poor results after resection
- Future arthrodesis may be indicated
Talocalcaenal coalition middle facet arthroplasty
- Linear incision from posterior-inferior medial malleolus to plantar-medial aspect of first cuneiform
- Incision carried deeply between FDL tendon and NV bundle (Tib. Post. and FDL retracted dorsally and NV bundle retracted plantarly)
- Middle facet coalition identified and resected (4-7mm)
- Arthroereisis?
Calcaneonavicular coalition radiographic evaluation
- CALCANEONAVICULAR - MO
- “comma sign” - protrusion of calcaneus toward navicular
- “anteater nose sign”
Calcaneonavicular coalition characteristics
- Extra-articular coalition
- In younger pt. with minimal secondary arthritic changes, resection arthroplasty is procedure of choice - (Juvenile-IA)
Calcaneonavicular coalition surgical treatment
- Lateral curvilinear or Ollier type of incision
- EDB origin reflected off calcaneus, retracted distally
- Must preserve the TN and CC joint ligaments
- Bar is generously resected (1 to 1.5cm)
- EDB muscle belly may be sutured into defect?
Calcaneonavicular coalition post-op
- NWB, below the knee cast for 3-4 weeks
- Cast may be bi-valved and subtalar and midtarsal joint ROM exercises begun
- Begin WB after 4-6 weeks
- Most freq. Post-op complication is recurrent bone growth
- Must consider triple arthrodesis with failure or severe secondary arthritic changes
Talonavicular coalition characteristics
- Intra-articular coalition
- Frequently asymptomatic
- If symptomatic, resection then fusion, as well as fusion of TC and CC joints recommended
Calcaneocuboid coalition
- Rare, intra-articular coalition
- Double arthrodesis of TN and TC joint may indicated
- Extra-articular coalition
- Similar to calcaneonavicular coalition
