Ankle Flashcards
The superficial deltoid ligament and deep deltoid ligaments role
superficial resists hindfoot eversion
Deep: medial stabilizer of ankle; restraint to external rotation fo the talus
how does the talus shape affect the ankle motion
Talus is wider anteriorly and narrower posteriorly, ankle rotates into more plantarflexion, thus the talus translate slightly anterior, unlocking itself from the omrtise.
with progressive plantarflexion or extreme dorsiflexion, dislocoation can occur
fixed bearing vs mobile bearing implants
fixed bearing, the polyethylene spacer is fixed to either the tibial or talar implant component
mobile bearing: have polyethylene spacer that is NOT attached to either the talar or tibial component and floats between the two . allows for some varus/valgus tilt and axial rotation
what does the agility device require for their TAR
arthrodesis of the distal tibiofibular syndesmosis
advantage for Hintegra
relies on minimal bone resection for placement in cancellous subchondral bone
Ankle/foot positioning for STJ arthrodesis
0-5 deg valgus, 10-15 deg external rotation of foot so 2nd ray aligns with tibial crest
pantalar position for fusion
The ideal position for a tibiocalcaneal or pantalararthrodesis fusion is 90 degrees of the foot relative to the leg, with slight ankle and/or hindfoot valgus, and approximately 10-12 degrees of pes abductus.
Indication when considering total ankle arthroplasty with ankle valgus as a result of malleolar malunion
fibular lengthening osteotomy
Indication when considering total ankle arthroplasty for ankle varus , as a result of chronic ankle instability
a medial malleolus lengthening osteotomy would be indicated
contraindications for TAR
- severe osteoporosis
- history of osteomyelitis
- diffuse osteonecrosis
- significant bone defect on the tibial and/or talar site.
- Charcot
- Non-manageable hindfoot malalignment Massive joint laxity (eg, patients with Marfan disease) Highly compromised periarticular soft tissues (eg, in patients with posttraumatic OA who underwent several previous surgeries) Severe sensomotoric dysfunction of foot/ankle Active soft-tissue or bony infection Additionally, TAR should not be considered as the first-choice therapy in patients with a high level of functional demand (eg, contact sports).
relative contraindications for TAR:
-heavy physical work, medium level of sports activities (eg, tennis, jogging, and downhill ski), high body mass index, diabetes, and smoking
-Significant preoperative varus or valgus deformity (>10°)
which TAR implant goes from a medial or lateral approach via a malleolar osteotomy
Eclipse Total ankle
which TAR implant goes from lateral malleolar osteotomy
Trabecular metal total ankle (zimmer/biomet)
which TAR has tibial surface covered with polyethylene flat that fits congruent surface of talar component with a sulcus that allows varus and valgus motion
salto talaris
for CBPS, what are the OCD tx
cast immobilization OATs subchondroplasty subchondral drilling debridement of ostechondral defect
CBPS: OCD dx
OCD; osteochondritis disseca
talar dome lesions
FDA approved TARs
Agility Salto Tolaris Eclipse Star Infinity Inbone Trabecular Metal total ankle
which TAR is approved without using cement
STAR
which two TARs uses the fibular osteotomy apporach
Eclipse and Trabecular Metal
post op protocol for TAR
immobilize for 6 weeks, and then protective weight bearing–> physical therapy
What’s a reason to keep the fibula during ankle fusion?
Fibula is required if you want to change ankle arthrodesis to TAR
Coronal deformity of __________ would be contraindicated for TAR
> 20 deg
What is the most appropriate shoe modification for a patient who has undergone a well-aligned ankle arthrodesis?
rocker sole shoes
common complications of TAR
Delayed wound healing (most common), subsidence ( gradual caving in or sinking of implant into bone), loosening, and malleolar fx
indications for supramalleolar osteotomies
distal tibial malalignment
Physeal disturbances
Degeneratie arthritis
malpositioned ankle arthritis
does not correct hindfoot deformities
what can increase risk for tibial component loosening on a TAR esp for Agility
syndesmotic nonunion
What is the most appropriate shoe modification for a patient who has undergone a well-aligned ankle arthrodesis?
rocker sole shoe
For any fibular osteotomy, where is the osteotomy typically performed? and what type of osteotomy?
3-5 cm above ankle joint: this area has somewhat meaphyseal and better healing potential
transverse osteotomy ideal
what is the most important part of the surgical technique for fibular lengthening
establishing good mobilization of syndesmosis to successfully lengthen and have fibula rotated into proper position
Tx for Berndt and Harty I-IV
Stage I and II, III medial lesions- conservative treatement: I: reduced activity, limited ankle motion
II/III:casting, patellar brace, ankle corsets, arch supports
III lateral/chronic ocd/stage IV:
removal of loose bodies and chronic lesions, drilling and curettage of defect, reductions with fixation of large fragments in acute injuries
-two K wires
- (absorbable) polyglycolic acid rod
-screws (1.5 or 2.0)
-Fibrin sealant (physiologic glue containing freeze dried human fibrinogen, bovine aprotinin, calcium chloride, and bovine thrombine)–granulation tissue replace this overtime; fibrin adhesive lasts only for 1 week
-mosaicplasty
ORIF-for displaced fragment; usually early injury of stage IV. chronic lesions more difficult for chronic lesion because of fibrous tissue that forms on cancellous bone
When are the collateral ligaments typically ruptured to some degree for OCD lesions
Grade II-Stage IV
Superficial peroneal nerve emerges from the crural fascia approximately
The superficial peroneal nerve is often encountered and emerges from the crural fascia 10-12 cm from the distal tip of the fibula.
What is the bosworth dislocation and what prevents it from being able to reduce?
rare fracture-dislocation of the ankle where the fibula becomes entrapped behind the tibia and becomes irreducible
posterolateral ridge of the distal tibia hinders reduction of the fibula
What is the ankle fusion technique that is indicated in a child to preserve the potential for growth of the distal tibial and fibular physis?
distraction-compression fusion
increased medial clear space in ankle indicates what stability
syndesmotic instability
