Miscellaneous Flashcards
Etiologies of hammer toes
- Flexor stabilization
- Flexor substitution
- Extensor substitution
Flexor stabilization
MOST COMMON
o Pronation of STJ leads to unlocked/hypermobile foot and therefore excessive “gripping”
o Flexors (FDL, FDB) fire earlier and stay contracted longer to stabilize the foot, but end up overpowering the interosseous muscles
o STJ pronation also leads to forefoot abduction making the QP muscle weak, allowing adductovarus rotation of 5th digit
Flexor substitution
LEAST COMMON
o Supinated foot type with weak gastro-soleal complex (Achilles rupture, Achilles surgery)
o Flexors gain advantage over interosseous due to weak gastro-soleal complex, they try to “substitute” for the weak muscle group
o Deep posterior and lateral muscles attempt to make up for weak gastro-soleal complex
Extensor substitution
o Pes cavus, neuromuscular contracture, equinus (these need to be corrected as well)
o Extensor digitorum longus gains advantage over the lumbricals, bowstringing of EDL
o Initially only swing phase hammering which will partially resolve during weight bearing
o Orthotics will not work due to the deformity predominating during swing phase
Virchow’s triad
Three factors that are commonly associated with the formation of thrombi
- Stasis
- Blood vessel injury
- Hypercoagulability
Stasis
Reasons for stasis
- Arrhythmias
- MI
- CHF
- Heart failure
- Immobilization
- Obesity
- Varicose veins
- Dehydration
Blood vessel injury
Reasons for blood vessel injury
- Trauma
- Fracture
- IV
Hypercoagulability
Reasons for hypercoagulability
- Neoplasm
- Oral contraceptives
- Pregnancy
- Surgery
- Polycythemia
Calculate ABI
- Determine brachial systolic pressure
- Determine ankle systolic pressure
- Ankle pressure divided by brachial pressure
Ranges of ABIs
1 = normal 0.5-0.8 = intermittent claudication <0.5 = rest pain, ulcers
Toe pressures in diabetics
> 55 mmHg = healing
45-55 mmHg = uncertain healing
<45 = no healing
At least 30 mmHg required for healing a wound on the digits
Seddon classification for nerve injury
- Neurapraxia
- Axonotmesis
- Neurotmesis
Neurapraxia
Bruised nerve - results in numbness that is reversible
Axonotmesis
Injury to axon that results in Wallerian degeneration, will regenerate over several months as long as gap is not too big
Neurotmesis
Complete severance of the nerve resulting in irreversible numbness
Sunderland’s classification for nerve injury
- First degree
- Second degree
- Third degree
- Fourth degree
- Fifth degree
First degree
A conduction deficit without axonal destruction
Second degree
Axon is severed without reaching the neural tube. Wallerian degeneration with regeneration. Regeneration is likely (axonotmesis)
Third degree
Degeneration of axon with destruction of fascicle with irregular regeneration
Fourth degree
Destruction of axon and fascicle and no destruction of nerve trunk, but a neuroma-in-continuity exists
Fifth degree
Complete loss - neuroma is likely and spontaneous nerve recovery is rare
Sullivan’s sign
Toes adjacent to Morton’s neuroma splay apart on weight bearing
Joplin’s neuroma
Similar to Morton’s neuroma but affecting the medial plantar digital nerve on the medial aspect of the first MPJ of the hallux
Similar symptoms to Morton’s neuroma - paresthesia and burning with pain at point of entrapment
Biomechanical etiology - caused by pronation or hallux limitus
Another name for flexor retinaculum
Lacinate ligament
This is the tarsal tunnel (where tarsal tunnel syndrome exists)
Types of anemia
- Microcytic
- Normocytic
- Macrocytic
Mnemonic to remember types of anemia
Microcytic: “I SAT”
Normocytic: “IN A HAM”
Macrocytic: “DAMN”
Microcytic
I = iron deficiency
S = sideroblastic anemia A = anemia of chronic disease T = thalassemia
Normocytic
I = infiltrative bone marrow disorder N = nutritional anemia
A = anemia of chronic disorder
H = hemolytic anemia A = anemia of renal insufficiency M = myelodysplastic anemia
Macrocytic
D = drugs (metformin) A = alcohol M = malabsorption syndromes N = nutritional anemias
Concepts of skin plasty
- Stress
- Strain
- Creep
- Stress relaxation
Stress
The force on the skin per cross sectional area
Strain
The change in length divided by the original length of the given tissue to which a force is applied
Creep
The increase in strain seen when skin is under constant stress
This occurs in a matter of minutes and is due to an extrusion of fluid from the dermis and a breakdown of the dermal framework
Stress relaxation
The decrease in stress when the skin is held in tension at a constant strain for a given time
This occurs over a matter of days to weeks and is due to an increase in skin cellularity and the permanent stretching of skin components
What concentration of phenol is most commonly used?
89%
Thick vs thin skin graft
- The thinner the graft the better the take
- The thicker the graft the better the function
Full thickness skin grafts
- Epidermis and all of the dermis
- Take is not as good
- Infection rate is higher
- Grafts do not shrink or change color
- Hair follicles preserved
Partial thickness (split thickness) grafts
- Epidermis and varying amount of dermis
- The thinner the graft, the more likely it will take because a higher number of blood vessels are transected and there is more opportunity for revascularization
- Grafts tend to shrink 50-70% and become hyperpigmented
Graft meshing
- A process by which multiple staggered rows of full thickness incisions are placed in a graft before application to the recipient site
Advantages of meshing
- Expands tissue allowing smaller graft to cover larger site
- Allows drainage of hematoma/seroma through graft
- Allows graft to drape well around irregular surfaces
Disadvantages of meshing
- Inferior aesthetic appearance after healing
- Graft becomes very delicate
- Easily torn
Graft donor site
Full thickness
- Flexor surface, especially groin
- Close primarily with 3:1 ratio
Partial-thickness
- Anterior/lateral thigh, upper inner arm, gluteal region, dorsum of foot
- Heal by secondary intention, control bleeding with thrombin/epinephrine/cautery and dress with tegaderm
Reasons for graft failure
- Hematoma (most common)
- Infection (second most common)
- Seroma
- Shearing forces
- Improper preparation of recipient site
Z plasty
- Angles permissible for Z-plasties are 45-60 degrees
- 60 degrees gives the greatest lengthening
- Angles less than 45 degrees result in impaired blood flow to the flaps and angles greater than 60 result in severe tension
- Particularly useful in treating linear scar contractures
V-Y plasty
- Skin lengthening technique
- The apex of the “V” can point distally or proximally
Derotational skin plasty for 5th digits
- Done in conjunction with an arthroplasty
- Acts to correct for the varus (frontal) and hammering (sagittal) of the digit
- Incision made from distal medial to proximal lateral
Most common sources of metastatic tumors
- Breast
- Lung
- Prostate
- Kidney
- Multiple myeloma
Most common benign primary bone tumor
Osteochondroma
Most common malignant primary bone tumor
Multiple myeloma
Malignant bone tumors
- Osteosarcoma
- Chondrosarcoma
- Fibrosarcoma
- Ewing’s sarcoma
- Multiple myeloma
Benign bone tumors
- Osteoma
- Osteochondroma
- Enchondroma
- Chondroblastoma
- Chondromyxoid fibroma
- Osteoid osteoma
- Osteoblastoma
- Non-ossifying fibroma
- Intraosseous lipoma
- Giant cell tumor (locally malignant)
- Unicameral bone cyst
- Enostosis
- Ossifying fibroma
- Aneurysmal bone cyst
- Chondroblastoma
