Hand Flashcards
What is the Fowler tenotomy?
For up to 35 degree chronic mallet deformity, dividing the deep attachment of the central slip, but leaving the overall apparatus intact.
What is the expected outcome after collagenase injection per joint?
PIPJ contracture 60% improvement
MCPJ contracture 85% improvement
Avg 1.4 injections
Range 1-4 injections
What is the likelihood of joint subluxation in a bony mallet deformity?
- 42% joint involvement or less: seldom
2. 52% or more joint involvement: consistently seen
Nail growth?
Normally 0.1mm per day
After loss, stunted for 3 weeks, then accelerated for 50 days, then gradual return to normal
Re-growth complete in 2 1/2 to 5 1/2 months (70-160 days)
Name and describe the four most common opponensplasties?
- FDS RF (now usually MF), route around FCU
A. Royal Thompson
B. Bunnell (phone proximal phalanx dorsal Ulnar to Volar radial - EIP (Burhalter), around ulnar wrist, good for high median and ulnar nerve compromise
- ADM (Huber)
- Camitz
What structures constitute the perionychium?
Germinal matrix, sterile matrix, hyponychium, eponychium, paronychium and nail
Describe how ultrasound works in physical therapy.
Continuous ultrasound preferentially heats deep structures, such as tendons without overheating the fat. Penetration is from 1 to 5 cm.
Describe the role of cryotherapy postoperatively.
9°C or 50°F
Applied within 24 hours of surgery it:
- reduces rate of chemical reactions occurring during acute inflammatory phase
- This reduces leukocyte activity
- This in turn reduces endothelial damage which decreases capillary permeability
- equals less interstitial fluid
- Also causes vasoconstriction and reduces prostaglandin production to reduce blood flow
Which type of TFCC tear is the hardest to diagnose on MRI?
Ulnar sided (Palmer IIb) are far harder to diagnose
Longitudinal forearm instability
Presentation (history)? Physical examination? X-ray? Also known as?
Fall from height onto outstretched hand with elbow extended
- Tenderness in mid forearm and DRUJ
- Almost always comminuted radial head fracture
- Essex–Lopresti lesion
Define Essex-Lopresti lesion
Longitudinal forearm instability with radial head fracture, interosseous membrane disruption and DRUJ instability
What percentage of Essex Lopresti lesions are missed initially and how many of those people have good outcomes after treatment?
75%, 20%
Explain the mechanism by which an Essex Lopresti lesion presents in a delayed fashion?
The radial head is excised and the interosseous membrane is only partially injured so the lesion is missed. Over time the partially damaged membrane attenuates and fails.
What is the primary stabilizer of the forearm?
The radial head
Explain how force is transmitted from the wrist through the forearm and ultimately into the elbow?
Normally, 80% of axial forearm load is transmitted via the radius at the wrist, but the central band of the interosseous membrane transmits some of that force to the ulna so that at the elbow 60% of the load is through the ulnohumeral joint.
Describe the anatomy and orientation of the central band of the interosseous membrane in the forearm?
The central band originates 60% of the way from the radial styloid proximally, runs distal and ulnar at 21° angle to the ulna and inserts at the junction of the middle and distal third of the ulna.
Name the structures that constitute the interosseous membrane from proximal to distal?
POC (proximal oblique cord, aids in PRUJ stabilization)
DOAC (dorsal oblique accessory cord), variable
Accessory band (variable)
Central band
Accessory band (variable)
DOB (distal oblique bundle), present in 40%, from ulna, runs distally to insert on radius, accounts for stability of DRUJ after displaced distal radius fracture even with a displaced ulnar styloid base fracture
After radial head resection how much axial load in the forearm is transmitted to the interosseous membrane?
90%
What structures must be disrupted in order to dislocate the DRUJ?
The TFCC and the IOM (especially the distal oblique bundle)
The TFCC is responsible for what percentage of mechanical stiffness of the forearm?
8%
In a cadaver model isolated radial head excision in a normal forearm axis causes how much proximal migration of the radius with axial load?
7 mm
In a cadaver model what happens after sectioning of the interosseous membrane with axial load through the radius?
There is now no transmission of force to the ulna, leading to premature wear of the RC jt
For every 1mm of proximal radial migration how much increase in load occurs at the distal ulna?
10%
What is the sensitivity, specificity and accuracy of MRI in detecting interosseous membrane injury?
93%, 100%, 96%
Describe how ultrasound is used to detect interosseous membrane rupture and it’s accuracy compared to MRI?
Requires an experienced ultrasonographer.
Requires volar to dorsal pressure to cause muscle herniation sign
96% accurate (no difference compared to MRI)
What is the radius pull test?
An intraoperative test in which longitudinal traction on the radius is exerted after radial head excision. More than 3 mm of proximal migration shows the need for replacement of the radial head because of interosseous membrane disruption
What is the radius joystick test?
It is an intraoperative test in which lateral traction is applied to the radial neck with maximal pronation to detect interosseous membrane disruption. This has never been studied in vivo.
What is the acute treatment for an Essex-Lopresti lesion?
- ORIF RH vs replacement
- Consider simultaneous repair or reconstruction of central band. This is controversial.
- Consider repair of TFCC
What is the appropriate treatment for a delayed presentation of an Essex Lopresti lesion?
- Replace radial head (partially restores length)
2 Ulna shortening osteotomy (perform osteotomy proximal to the distal IOM attachment)
- Consider simultaneous reconstruction of the central band (BLB allograft is probably best. Double-stranded FCR graft may also be appropriate)
What is the ultimate salvage procedure after multiple surgical failures to correct an Essex Lopresti lesion?
Creation of a one bone forearm
As opposed to longitudinal forearm instability (Essex Lopresti), describe transverse forearm instability and give three examples?
Transverse forearm instability patterns generally spare the central band of the IOM:
- Galeazzi fracture
- Monteggia fracture
- Isolated DRUJ dislocations
Describe the orientation of the distal oblique bundle of the interosseous membrane, and it’s anatomical attachments?
The distal oblique bundle inserts at the proximal margin of the sigmoid notch (proximal to most distal radius fractures), and originates from the ulna proximately, precisely where the axis of rotation of the forearm intersects the radial surface of the ulna)
What is the normal anesthetic used in a Bier block?
0.5-1% lidocaine, or 0.5% prilocaine
Max safe dose 3mg/kg
Classification of Kienbock’s Disease
I. X-rays normal, MRI positive, bone scan positive
II. Fracture or sclerosis on X-ray
IIIa Collapse of lunate without carpal collapse
IIIb Collapse of lunate with carpal collapse
(Newer addition: >60deg scapholunate angle. Studies show that attempts to salvage the lunate in this instance will not succeed)
Carpal Height Ratio=Carpal Height\Middle finger MC height
VI Generalized arthritis
What is a terrible triad elbow injury?
Radial head fracture (driven posterior to coronoid), coronoid transverse shear fracture (2-3 mm fragment), LUCL tear (occurs in this order)
