75 - Tarsal Coalition Flashcards
Tarsal coalition
- Tarsal coalition exists when a union causes restricted motion or absence of motion between two or more tarsal bones
- Bars vs. Bridges
Bar coalition
- Extraarticular coalition that occurs outside a normal joint
- Example: Calcaneonavicular Bar
Bridge coalition
- Intraarticular coalition that occurs at a normal joint site
- Example: Talocalcaneal Bridge
Division of tarsal coalitions into extraarticular and intraarticular coalitions
Extraarticular coalitions (BARS)
o Calcaneonavicular
o Cubonavicular
Intraarticular coalitions (BRIDGES) o Talocalcaneal (middle, posterior, anterior, combination) o Talonavicular o Calcaneocuboid o Naviculocuneiform
History
- Pre-Columbian Indian skeleton 1000AD
- Buffon 1769 – First written description
- Sir Robert Jones 1897 – Peroneal Spastic Flatfoot: Did not associate it with tarsal coalition
- Kirmission 1898 – First radiographic description
Classifications
- Etiology
- Anatomic
- Tissue Type
- Articular Involvement
Etiology
- Congenital = Most common cause of tarsal coalition in pediatric patients
- Acquired = Most common cause of tarsal coalition in adult patients
Congenital etiologies
- Pfitzner theory
- Leboucq theory
Pfitzner
o Incorporation of accessory ossicles into the normal tarsal bones on either side of a joint or in close approximation with one another
Leboucq
o Failure of differentiation and segmentation of primitive mesenchyme
o Heritable defect (autosomal dominant)
o Insult is detected in first trimester
o THIS IS THE PREVAILING THEORY = AUTOSOMAL DOMINANT
o If something is something is autosomal dominant, it should show up in 75% of offspring
Aqcuired etiologies
- Arthritis
- Infection
- Trauma
- Neoplasm
Tissue type classification
- Syndesmosis: Fibrous union = Incomplete union with motion
- Synchondrosis: Cartilaginous union = Incomplete union with motion
- Synostosis: Osseous union = Complete union without motion
Articular involvement (Downey Classification) – KNOW THIS***
- Juvenile (Osseous Immaturity)
- Adult (Osseous Maturity)
Juvenile (Osseous Immaturity)
Type I: Extraarticular Coalition
A: No Secondary Arthritis
B: Secondary Arthritis
Type II: Intraarticular Coalition
A: No Secondary Arthritis
B: Secondary Arthritis
Adult (Osseous Maturity)
Type I: Extraarticular Coalition
A: No Secondary Arthritis
B: Secondary Arthritis
Type II: Intraarticular Coalition
A: No Secondary Arthritis
B: Secondary Arthritis
SAME AS JUVENILE
Incidence – KNOW THIS
- 0.04% - 1.4% in overall population
- No racial preference
- 50% Bilateral
- 4:1 male/female? – These could just be bad studies, so not confident on this
- Talocalcaneal Coalition – 48.1% = HIGHEST INCIDENCE
- ***Calcaneonavicular Coalition – 43.6%
- ***Other – 8.3%
Clinical Findings
- Pain
- Limitation of motion and rigid flatfoot – most likely cause of unilateral pediatric flatfoot
- Muscle spasm
- No symptoms in 22% of patients – Patients often mistreated for ankle sprains and sinus tarsi syndrome
Pain
- Deep aching pain in area of coalition
- Often localized to sinus tarsi or entire rearfoot
- Pain with walking over rough uneven terrain (this is something that can cause pain initially)
- May occur with secondary arthritis (a lot of times a complication of a surgical fusion is arthritis in neighboring joints – these patients have congenital fusion leading to the same thing)
- Onset is insidious after activity or trauma and relieved with rest
- May begin with ossification, rarely neuritic
**Ossification ** KNOW THIS
- Talonavicular Coalition: 3-5 years
- Calcaneonavicular Coalition: 8-12 years
- Talocalcaneal Coalition: 12-16 years
Limitation of motion of STJ & MTJ
- Most obvious clinical finding
- STJ exhibits limited inversion - As ossification increases, motion decreases
- Hubscher Maneuver
Hubscher maneuver
o Dorsiflexion of the hallux with patient standing
o Medial band of plantar fascia is tightened
o If deformity is FLEXIBLE – Arch height will increase and rearfoot will supinate
o If deformity is RIGID – No change in arch height
Muscle spasm
- Tonic muscle spasm of the peroneal tendon – Not clonic (neurological)
- Due to painful subtalar joint motion, the peroneal tendons guard to restrict motion and immobilize the joint
o It hurts to invert so peroneals over-fire to prevent inversion, so eventually they spasm
o Comfortable foot position is in valgus (EVERTED)
o Common peroneal nerve block – May need to do this with lidocaine in order to check ROM if the peroneals are spastic - Peroneal spastic flatfoot does NOT always develop in a tarsal coalition
- NOTE: there are other etiologies of peroneal spasm, so it is not always tarsal coalitions
Radiographic evaluation – Calcaneonavicular bar
Demonstrated on an oblique radiograph
o Comma sign or Anteater sign
Osseous easier to diagnose
o Soft tissue coalitions
o Close proximity of Calcaneus and Navicular
o Irregular lateral Navicular cortical surface
o Flattening of Navicular laterally
o Hypoplasia of head of Talus
Radiographic evaluation of talocalcaneal coalition
Demonstrated on a lateral radiograph
o Diminished posterior or middle facet
o Halo sign (sclerosis of sustentaculum tali)
o Narrowing of posterior facet
o Talonavicular beaking (secondary arthritic change)
o Flattening of lateral talar process
Calcaneal Axial (Ski-jump, Harris and Beath view)
o Looking for facet obliquity
o Parallel or less than 25 degrees
