AOAO BOARD REVIEW FOOT/ANKLE SECTION

2020

William E. Saar, D.O.

TriRivers Musculoskeletal Centers – UPMC

Faculty – UPMC Foot/Ankle Fellowship Program

Common Ft/Ankle Topics Covered

• Posterior Tibial Tendon Dysfunction

• Hallux Valgus

• Diabetic Foot Disorders

• Trauma

• Hallux Rigidus / Arthritis

• Talar (OLT) Lesions

• Achilles Conditions

• Lesser Toe Deformities

• Foot/Ankle Biomechanics-Gait

Posterior Tibial Tendon Dysfunction

• Etiology

• Early (Hypovascularity)

• Late (Primary dynamic support lost)

• Female:Male (3:1); Avg. Age 50-60

• Presentation/Exam/Studies

• “Too many toes” Sign (Forefoot abduction)

• Hindfoot valgus (Rigid/Flexible)

• Single heel rise pain/inability

• Xray

• Lateral Talo-1st MT Angle (Meary) – TN ‘Sag’

• AP – Talar Head Uncoverage

Posterior Tibial Tendon Dysfunction

Posterior Tibial Tendon Dysfunction

Hallux Valgus Deformity

• Pathoanatomy

– Plantarlateral of AbH pronates Phalanx

– Lateral Deviation of EHL/FHL causes valgus progression/pronation

– 1st MT Head moves medially off sesamoids

– Lateral Capsular contracture / Medial Capsular attenuation

• Radiographic Features/Measurements

– HVA / IMA / HVI / DMAA (Congruency??)

• Treatment

– Based on: 1) Angular Measurements; and 2) Clinical Scenario

Hallux Valgus Deformity

Hallux Valgus Deformity

Diabetic Foot Disorders

• Pathoanatomy

– Neuropathy

• SW 5.07 Monofilament depicts protective sensation

• Motor neuropathy MC involves Common Peroneal Nerve – Tib Ant

weakness and Footdrop

– Angiopathy (Healing potential reduced with)

• Total Protein < 6 g/dL

• Total Lymphocytes (WBC) < 1,500

• Albumin Level < 2.5 g/dL

• TCOM < 40 mmHg

• Absolute Toe Pressure < 40

• ABI < 0.5

Diabetic Foot Disorders

• Diabetic Wound Classification (Wagner)

• If Ulcer probes to bone, 67% chance of osteomyelitis (often polymicrobial)

– Equinus Contracture / Level of Amputation

Diabetic Foot Disorders (Charcot)

• Neurotraumatic: Repetitive microtrauma due to lack of protective sensation

• Neurovascular: Autonomic dysfunction increasing blood flow leading to bone resorption and weakening

Diabetic Foot Disorders (Charcot)

• Charcot Classification (Eichenholtz)

Foot/Ankle Trauma – Calcaneus Fracture

• Intra-articular

– Sanders Classification - based on fx pattern through posterior facet

– Lateral wall blowout – subfibular impingement and peronealtendon encroachment

– Indications: facet displacment >2-3mm; Bohler’s angle flattening; tuberosity varus

– Improved Surgical Clinical Outcomes: Age<29; women; non WC cases; significant displacement and flatter Bohler’s angle

• Extra-articular

– Tongue type fracture: displacement places posterior soft tissue at risk; requires urgent reduction/fixation

Foot/Ankle Trauma – Talus Fractures

• Blood Supply

– Provided by: posterior tibial, dorsalis pedis, and perforating peroneal;

artery of tarsal canal-talar body

• Hawkins Classification (see next slide)

• Radiographic Signs

– Hawkins Sign: Subchondral linear lucency of talar dome (indicative of talar

revascularization)

– Sclerosis: Does NOT guarantee that AVN has occurred, but it is suggestive

– Canale View

• Lateral Talar Process (Snowboarder’s Fracture)

Foot/AnkleTrauma – Talus Fractures

• Hawkins Classification

Foot/Ankle Trauma – Lisfranc Injury

• Second MT base is ‘keystone’ of arch

• Ligament b/w medial cuneiform and 2nd MT Base

• Weightbearing views; Evaluate for ‘Fleck Sign’

– Know anatomic landmarks

• Treatment

– Nonsurgical for nondisplaced injuries

– Surgical: Anatomic ORIF vs Primary Arthrodesis

• Based on extent of ligamentous / bony injury (comminution)

Foot/Ankle Trauma – Lisfranc Injury

Foot/Ankle Trauma – 5th MT Fractures

Foot/Ankle Trauma – 5th MT Fractures

• Treatment

– Conservative: Immobilization; NWB (Zone 2)

– Surgical: ORIF (Intramedullary/Plate-Screw)

Arthritis – Hallux Rigidus

• Pathoanatomy: Unknown; Anatomic/Genetic Predisposition, and Repetitive Trauma• Grading

Treatment

Grade 0/1: NSAIDs; Activity Mod.; Orthotic (Morton’s Ext)

Grade ½: Dorsal Cheilectomy

Grade ¾: Arthrodesis (vs. Arthroplasty)

Arthritis – Tibiotalar

• Mostly Post-traumatic in origin

• Commonly results from non-anatomic fracture healing – altering

joint contact forces and load bearing

• Tibiotalar (Ankle) Arthrodesis

– Reliable relief of pain: Young laborers/less active elderly

patients

– Up to 50% subtalar arthritis at 10 year F/U

– Position: Neutral DF (90°); 0-5° Valgus; 5-10° Ext Rotn

Arthritis – Ankle Replacement

• Indicated in posttraumatic, elderly, inflammatory arthritis

• Contraindications: Bone Loss, Severe Deformity, AVN, Obesity, Infection, Charcot, Instability

• TAA has shown the best outcome in patients with Osteoarthritis

Talar (OLT) Lesions

• Lateral Lesions

– Traumatic; often symptomatic/displaced

– More anterior/central; usually shallow/wafer shaped

• Medial Lesions

– More common; Atraumatic

– Larger; More posterior; Cup shaped and deeper

• Treatment

– Nondisplaced/Incomplete: Protected WB Cast x 6 weeks

– < 1 cm.: Arthroscopic removal with/without microfracture

– > 1 cm. with intact cap: Retrograde Drilling

– >0.5 cm. and displaced: ORIF vs. OATS vs. Restorative Procedures

Talar (OLT) Lesions

Achilles Conditions

• Non-insertional Tendonitis/Tendinopathy

– Pathophysiology: Abnormal vascularity 2-6 cm. proximal

to insertion with overuse, microscopic tearing of tendon

• Treatment

– Activity modification; Heel Lifts; NSAIDs; PT

– Open Excision with tubularization/repair

• Tendon Transfter (>50% degeneration)

Achilles Conditions

• Insertional Tendonitis (Haglunds/Spur/RC Bursitis)

Pathophysiology: Repetitive trauma and insertional/bursal inflammation

– Treatment

• Activity Modification; Heel Lifts; NSAIDs; PT

• U/S Guided Bursal Injection

• Sx – Bursal Excision / Resection Haglunds-Spur / Tendon Augmentation (FHL) if

> 50% degeneration

Achilles Conditions

• Achilles Rupture– Risk Factors: Weekend warriors, Fluoroquinolones, Steroid

Injections

– Eccentric Achilles contraction with rupture 4-6 cm above insertion

– Treatment• Non-Op: Functional Rehab; Decreased Op Complications;

Possible Increased Re-rupture• Open Repair• Percutaneous Repair: Less wound issues; Sural Neuropraxia• Reconstruction with V-Y Advancement for defects 2-5 cm.

with/without FHL Transfer

Lesser Toe Deformities

• Pathoanatomy: Typically results from tendon imbalance, resulting in synovitis and MTP pain due to deformity

Lesser Toe Deformities

• Treatment

– Non-operative: Shoe modification (Wide/Deep Toe Box);

Foam/Silicone Sleeves; Budin Splints

– Operative

• Tendon Transfers (usually FDL to EDL)

• Tenotomies

• PIP Joint Resection/Fusion for rigid deformities

(High rate of nonunion)

• Osteotomies (Weil, etc…)

Lesser Toe Deformities

Biomechanics/Gait• Hindfoot

– Subtalar joint responsible for inversion/eversion

– Transverse Tarsal Joints (TN/CC)

• Inversion LOCKS the TT Joints in toe off

• Eversion UNLOCKS the TT Joints to accommodate heel strike

• Midfoot (Naviculocuneiform and TMT Joints)

– 3 Columns: Medial; Middle (Keystone); Lateral (flexible)

– Ligamentous Support: Interosseous (Lisfranc); Plantar; Dorsal

• Forefoot

– Transverse MT Ligament holds Hallux sesamoids in place

– Plantar Plates: Weakest at MT Neck origin, when attenuated can be deformed by EDL and increase dorsal translation of Proximal Phalanx

Biomechanics/Gait

• Windlass Mechanism: Tightening of the Plantar Fascia (medial calcaneal tuberosity to MT bases) during toe off to increase arch height/support