Foot & Ankle Flashcards
Name and describe 2 classifications for charcot foot
Eichenholtz:
Stage 0: joint edema, x-rays negative
Stage 1: fragmentation
- Local edema
- osseous fragmentation with joint dislocation
Stage 2: coalescence:
- decreased local edema
- x-rays show coalescence of fragments and absorption of fine bone debris
Stage 3: Reconstruction
- no local edema
- x-rays show consolidation and remodeling of fracture fragments
Brodsky
Type 1: (midfoot)
- TMT and naviculocuneiform joints (60%)
Type 2 (Hindfoot):
- subtalar, TN, CC joints
Type 3: Ankle of calcaneus
- A: tibiotalar joint
- B: Follows fracture of calcaneal tuberosity
Type 4: Combination of areas
Type 5: solely in forefoot
How many people get subtalar arthritis 10 years post tibiotalar arthrodesis?
50%
Syndesmosis screw technique
Be specific
2 x 3.5 or 4.5mm syndesmotic screws
Through 3-4 cortices
2-5cm above plafond
Screw material:
No difference between types of metal or bioabsorbable
Cortices:
No difference between 3-4
Number of screws:
2 is better
Position of foot
Recent studies challenge the principle of holding the ankle in maximal dorsiflexion to avoid over tightening
Post-operative care:
Typically non-weight bearing 6-12 weeks
May prolong if screw breakage is a concern
Name 3 gait advantages of total ankle replacement vs. arthrodesis
Increased stride length
Improved cadence
Increased stride velocity
4 common technical errors in Total ankle arthroplasty
Prosthesis is too lateral
Prosthesis is too small - will subside
Failing to solve preoperative varus/valgus malalignment
Attempting to replace an ankle that is too anteriorly subluxed
os trigonum syndrome is associated with pathology in what structure?
FHL
What are Scarf and Ludloff osteotomies used for? Differentiate them in one sentence.
Promixal metatarsal osteotomies for the treatment of moderate hallux valgus, usually in combination with a modified McBride distally.
See picture for differences.
Recalcitrant forefoot plantar ulcers
What is an important aspect of treatment
TAL vs. gastrocs lengthening
Decreaes plantarflexion and decreases pressure on forefoot
Neuropathic joint
Technetium bone scan will be
Indium WBC scan will be
Tc: ± positive in charcot (positive for OM)
indium WBC scan: negative in charcot (+OM)
Sectioning of which collateral ligament leads to more instability?
Accessory
B/c it attaches directly to the plantar plate
(vs. proper collateral, attaches to the proximal aspect of the phalanx)
Three differentials for posterior ankle pain not involving the Achilles.
- Os Trigonum Syndrome
- Posterior impingement
- FHL Tendonitis
Describe ankle arthroscopy portals
Anteromedial
- Primary viewing portal
- Established 1st
- medial to tib ant & lateral to medial malleolus
- Danger: saphenous nerve & vein
Anterolateral:
- Primary viewing portal
- Lateral to peroneus tertius & superficial peroneal nerve & medial to lateral malleolus
- Danger: Dorsal cutaneous branch of SPN
Anterocentral
- Anterior viewing portal
- Medial to EDC and lateral to EHL
- Not commonly used due to risk to DP artery
Posterolateral
- Posterior viewing portal
- 2cm proximal to tip of lateral malleolus
- Between peroneal tendons and achilles tendon
- Danger: sural nerve and small saphenous vein
Posteromedial
- posterior viewing portal
- just medial to achilles
- Risks: posterior tibial artery
Diagnosis & Treatment (chronic)
Ankle synovitis
Arthroscopy and synovectomy
What are 2 associated conditions of anterior ankle impingement?
Ankle instability (up to 35% will continue to have pain after stabilization procedure)
OCD
(Technically NOT OA, b/c this is pre-OA)
Best predictor of post-op ROM with TAA
Pre-op ROM
Differenes of Juvenile HV vs. Adult:
Juvenile is:
- Often bilateral
- Often familial
- Pain is not the primary complaint
- varus 1st MT with widened IMA usually present
- DMAA usually increased
- often associated with flexible flatfoot
In os trigonum syndome, in the absence of an obvious os trigonum, what may be another cause?
scar tissue behind posterior talus (where the os should be)
Found on MRI
4 pathologic conditions secondary to cavus foot
(what does cavus foot cause, NOT what causes cavus foot)
Lateral column stress fractures
Lateral ligament injury
peroneal tendon injury
Lateral column overload
1st step in lisfranc ORIF?
Intercuneiform reduction and fixation
Name & Describe classic tendon transfer for foot drop
Bridle Procedure
- Classically PTT, TA & PL transfer & tritendon anastomosis
Tib post:
- transferred to middle/lateral cuneiform
- THROUGH split in tib ant
Tib Ant
- Anastomosed to Tib post
Peroneus Longus
- PL: cut 5cm above fibula
- Proximal end sewn to PB
- distal end is anastomosed to newly transferred PTT
Effect
- As tib post pulls, it will also pull on PL and TA, causing dorsiflexion & eversion (motion lost with peroneal nerve injury)
Classification of Hallux Rigidus:
Coughlin & Shurnas Classification
Grade 0:
- Stiffness with normal x-ray
Grade 1:
- mild pain at extreme range of motion
- X-rays show mild dorsal osteophyte and normal joint space
Grade 2:
- Moderate pain with range of motion
- Moderate dorsal osteotomy
- <50% joint space narrowing
Grade 3:
- Significant stiffness and pain at extreme ROM. No midrange pain
- Xrays show severe dorsal osteophyte >50% joint space nrrowing
Grade 4:
- significant stiffness and pain at extreme ROM AND pain at mid-range
- x-rays: same as grade 3
List some differentials for failed treatment of ankle sprain (i.e. missed concommitant injuries/pathology)
- injury to the anterior process of calcaneus
- injury to the lateral or posterior process of the talus
- injury to the base of the 5th metatarsal
- osteochondral lesion
- injuries to the peroneal tendons
- injury to the syndesmosis
- tarsal coalition
- impingement syndromes
Indications for 1st MTP arthrodesis in HV:
CP
Down’s
Ehler-Danlos
RA
Gout
Severe DJD
What is the mechanism for injury to the superior peroneal retinaculum?
Dorsiflexion & inversion
During reflexive contraction of the peroneal muscles
4 medications you can use in Charcot Foot
bisphosphonates
neuropathic pain meds
antidepressants
topical anesthetics
Isolated fusion of the calcaneocuboid, subtalar, and talonavicular joint arthrodeses result in how much limitation in motion?
limit hindfoot motion by approximately 25% (CC), 40% (ST), and 90% (TN)
Name 2 anatomic risks for peroneal tendon instabiliy or rupture
Low lying peroneus brevis muscle
Presence of peroneus quartus muscle
Most common foot position after CVA or TBI
equinovarus
Risks of failure in isolated subtalar arthrodesis (5)
smoking
the presence of more than two millimeters of avascular bone at the arthrodesis site
failure of a previous subtalar arthrodesis
Use of structural allograft (should use autografto)
Adjacent ankle arthrodesis
What nerve can cause a painful neruoma if damaged during medial capsular imbrication for HV?
Medial branch of dorsal cutaneous nerve (SPN)
What must you do after IM screw of 5th MT base fracture (post-op care)
wait until clinical AND radiographic healing before return to sports
Post talar neck fracture, patient comes back with this (see picture)
best Management
TTC
?TAR?
5 radiographic changes of charcot neuropathy
obliteration of joint spaces
fragmentation of articular surface of a joint leading to subluxation/dislocation
Scattered “chunks” of bone in fibrous tissue
Surrounding soft tissue edema
Joint distension by fluid
HO
Which 1st toe sesamoid is larger?
Tibial (medial)
Medial supramalleolar osteotomy done usually for what?
Usually opening wedge for
varus ankle alignment & medial joint space narrowing
What is this deformity?
Hammer Toe
(Boutiennier of the foot)
Patient 3 months after TBI and has equinovarus foot
Surgical plan?
WAIT
Takes:
6-18 months post CVA for full extent of recovery
1-2 years (or several) post TBI for full extent of recovery
wait until after these times for surgery
What is removed with a cheilectomy?
Resection of dorsal osteophyte and 25% of the dorsal aspect of the metatarsal head.
(Hallux rigidus)
Cause and deformity of Hammer toe?
Overpull of the EDL
Causes Flexion of PIP and extension of DIP
Hallux valgus obviously involves valgus. What is the secondary deformity and what causes it?
Pronation.
This is caused by abductor hallicus as it migrates plantarly and medially.
What amount of dorsiflexion is requried for normal gait?
Unknown
Ranges fro 15-90 degrees
(WHat joint are we talking about? Nothing dorsiflexes 90 degrees)
Muscle imbalance in spastic equinovarus foot
Surgical treamtent
Strong TA (major) and PT, FHL, FDL (minor)
SPLATT, TAL, ± tib post transfer to dorsum of foot
Classification system of Hallux Rigidis
Based on radiographic & exam findings
0:
- exam: Stiffness
- xrays: normal xrays
I:
- exam: mild pain at extreme ROM
- Xrays: mild dorsal osteophyte with normal joint space
II:
- exam: moderate pain with ROM
- x-rays: moderate dorsal osteophyte with
III:
- exam: significant stiffness & pain at extreme ROM. No mid-range pain
- x-rays: severe dorsal osteophyte with >50% joint space narrowing
IV:
- exam: significant stiffness & pain at extreme ROM. (+) mid-range pain
- x-rays: same as III (severe dorsal osteophytes with >50% joint space narrowing)
Surgical approach for total ankle replacement?
Anterior
between EHL & TA
Risk of OM if a diabetic foot ulcer probes to bone?
65%
What are this?
What do you have to do before definitive management
What’s definitive manageent
Digital artery aneurysm
Must see if there is adequate collateral circulation
Treatment
Resection if there is adequate collateral circulation
Graft and repair if there is not adequate circulation
Treatment of midfoot arthritis that failed non-op management
Be specific
Outcomes?
1st ray TMT arthrodesis
2nd/3rd naviculocuneiform/intercuneiform joint arthrodesis
4th/5th ray - don’t fuse as it allows for accomodation of the foot during gait
Can do interpositional arthroplasties of 4th/5th in certain cases
Can fuse b/c non essential
Will lead to good outcomes with near anatomic function of the foot preserved
Contraindications to TCC
Absolute: infection
Relative
marginal arterial supply to area
patients unable to comply with cast care
patient unable to tolerate case (cast claustrophobia)
Patient has viral destruction of anterior horn cells.
Clinically she has motor weakness without sensory changes.
Diagnosis?
Poliomyositis.
*** patients can get post-polio syndrome 20-30 years after initial infection which invovles further brreakdown of nerves.
Tib ant contracts eccentrcialyl during what phase of gait?
Heel strike
Diabetic foot ulcer: Describe classification and treatment by Wagner
Grade 0:
- Skin intact
- “Foot at risk” due to deformities
- Treat with shoe modification & serial exam
Grade 1:
- Superficial ulcer
- Office debridment & TCC
Grade 2:
- Deeper, full thickness ulcer
- Formal operative debridement & TCC
Grade 3:
- Deep abscess or OM
- Formal operative debridement & TCC
Grade 4:
- Partial gangrene of forefoot
- Local vs. larger amputation
Grade 5:
- Extensive gangrene
- Amputation
Provocative test fo Morton’s neuroma (2)
Mulder’s click
bursal click may be elicited by squeezing MT heads together
Webspace compression test
Pain with compression of MT
4 technical risk factors for intraoperative fracture in total ankle arthroplasty
Overextending the plafond cut too medially or laterally
Making a cut too proximal in the tibia
Using an over-sized tibial component
Distraction of the ankle with an ex-fix
Ottawa ankle rule criteria
inability to bear weight
medial or lateral malleolus point tenderness
5MT base tenderness
navicular tenderness
Name 3 surgical options for severe hallux rigidus. Which one would you recommend?
MTP arthrodesis: gold standard
MTP arthroplasty: don’t do this! Long term results lead to osteolysis & synovitis
Keller Resection Arthroplasty: for low demand patients
Most common complication wiht total ankle arthroplasty
2 ways to prevent it
Wound complications
Prevent by:
Long incision to prevent tension on wound
Avoid incising tib ant sheath - prevents bowstringing and wound issues
Treatment algorithm for talar OCD
SLC + NWB x6 weeks:
- Nondisplaced, acute injury
Removal of loose fragment & Microfracture
- displaced small fragment with minimal bone on the osteochondral fragment
- Size <1cm
Retrograde drilling
- Size >1cm with intact cartilage cap
ORIF vs. osteochondral grafting
- Displaced >0.5cm
When do you operate in Charcot foot?
Once inflammation has gone down
so
Coalescence phase
4 muscles causing deformity in hallux valgus
Valgus of 1st toe leads to:
lateralization of sesamoids and respective heads of FHB
Adductor hallucis, attached to fibular sesamoid and lateral proximal phalanx, becomes deforming force
lateral deviation of EHL worsens deformity
Plantar and lateral migration of abductor hallucis casues plantar flexion & pronation
Best shoe modifiaction for reducing risk of plantar apex deformity in Charcot foot?
Double rocker bottom
Normal tibi/fib overlap
>6mm (some say 10mm) on AP
>1mm on mortise
Stance and swing make up how much of the gait cycle?
Stance: 60%
Swing: 40%
Main restraint to proximal migration of the talus?
Interosseous ligament (part of distal tibiofibular syndesmosis)
4 things you must do in tarsal tunnel release
ID the tibial nerve proximally and trace it down
Release Flexor retinaculum
Release Deep investing fascia of lower leg
Release Superficial and deep fascia of abductor hallucis
Surgial indications in Charcot foot
Recurrent ulcers
Instability not controlled by a brace
Where does Baxter’s nerve get entrapped?
Becomes compressed between;
fascia of abductor hallucis longus
&
medial side of quadratus plantae
Define turf toe & give 2 defining features
Hyperextesion injury to plantar plate and sesamoid complex of the 1st MTP
Characteristic features:
- inability to push off
- reduced agility
1st line treatment is conservative
During gait, when do the Quads fires concentrically ?
Midstance
2 options for tendon transfers in CMT?
TP to dorsum of foot
PL to brevis
What is the treatment for juvenile HV and how long should this be done for?
Non-operative until physes close
3 reconstruction options for tibialis anterior ruptures:
Sliding tendon graft
EHL tenodesis/transfer
Free tendon autograft
Allograft
how do you treat the bony deformity assciated with plantar ulcers?
Excise them
Helps prevent recurrence
How much ROM can TAA be expected to add?
None.
Expect no more than the pre-op ROM.
Mueller-Weiss Disease
Adult onset Navicular AVN
vs. Kohler’s disease (paediatric onset)
In ankle fusion, what should you do with the lateral malleolus?
Retain it - leaves the option for total ankle arthroplasty in the future
Treatment options for bunionette
Non-op
- works in up to 90%
Surgical
Type I:
- lateral condelectomy
Type II/III
- Distal MT Medializing osteotomy (if low IMA)
- Oblique diaphyseal rotational osteotomy (if high IMA)
- AVOID proximal osteotomy as poor healing (think Jones)
What clinical test differentiates between high ankle sprain and low ankle sprain?
Compression test
They will use this on the exam stem to differentiate between the two
Approach to foot compartment syndrome fasciotomy
3 incision
2x dorsal
one just lateral to 4th MT
one just medial to 2nd MT
1 medial
start: 4cm anterior to posterior heel & 3cm superior to plantar surface
Cause and deformity of Mallet Toe?
FDL contracture causing DIP hyperflexion
Tarlar OCD location with a traumatic hx?
3 characteristics of this lesion
Lateral talar dome
(medial has atraumtic history)
Less common
More superficial and smaller
Lower incidence of spontaneous healing
More often displaced and symptomatic
More central or anterior
What is the relationship of teh subtalar joint and the transverse tarsal joint?
When is this important?
Inversion of teh subtalar joint locks the transverse tarsal joint
Allows for a stable hindfoot/midfoot during toe-off
Name the foot deformity associated the myelomeningocoele at:
L1
L2
L3
L4
L5
S1
L1-L3: equinovarus
L4: cavovarus
L5: calcaneovalgus
S1: foot deformity only (no ankle)
Most sensitive test for diagnosing OM
MRI
Contrast OCDs of the medial versus lateral talar dome.
medial talar dome
usually no history of trauma
more common
more posterior
larger and deeper than lateral lesions
lateral talar dome
usually have a traumatic history
more superficial and smaller
more central or anterior
lower incidence of spontaneous healing
more often displaced and symptomatic
What is the gold standard to determine whether a diabetic ulcer will heal?
What are 2 things that must be present for an ulcer to heal
Gold standard:
transcutaneous oxygen pressure >30mmHg (or 40 depending on the resource)
To heal an ulcer, you must have:
transcutaneous O2 pressure >30mmHg
ABI >0.45
Foot position in ankle fusion
Neutral plantar/dorsiflexion
5 degrees of hidnfoot valgus
rotation equal to contralateral foot
What is this deformity?
Mallet Toe
List the treatment options in relation to gap present in achilles tendon
0-2 cm: reapproximation
2-5 cm: V-Y Lengthening
5-8/10 cm: Gastrocs turndown +/- FHL augment
>10 cm: allograft
Who gets os trigonum syndrome
What are the main symptoms?
Dancers and soccer players
Posterior ankle pain exacerbated by:
- dancing on pointe or demi-point
- doing pushoff maneuvers
What is the treatment for a failed silicone implant used to treat hallux rigidus?
- Removal of implant and synovectomy
- If there is lesser toe metatarsalgia then fuse the 1st MTP
In isolated MT fracture, what holds the MT in place leading to minimal displacement?
What happens in multiple fractures?
Intermetatarsal ligaments
Displacement b/c of inability of IMT ligaments to hold MT in place