Flexor Tendon Injuries Flashcards
Blood Supply of Hand
The hand is supplied with blood from both ulnar and radial arteries (not great blood supply)
Ulnar and Radial arteries join in 2 arches:
- Superficial Palmar Arch = superficial to flexor tendons
- Deep Palmar Arch = deep to flexor tendons
People have anatomical variations = deep arch can be a little more proximal, surgeon can accidentally hit deep palmar arch = hand will be black and blue
Prefer mini open procedure b/c you know they did a good release
Allen’s test confirms the blood supply integrity
Finger Blood Supply
Neuromuscular bundles
- Contain digital arteries, vein, and nerve
- 2 Bundles: one radial and the other ulnar
Lacerations usually gets vascular bundle
Tendon Nutrition
How does tendon get blood flow, oxygen and other nutrition?
2 Sources:
- Intrinsic: Vascular perfusion (blood supply)
- Extrinsic: Diffusion from synovial fluid (helps them glide freely)
Intrinsic Tendon Nutrition: Vinculi
Vinculi = how tendons and fingers (flexor tendons) get blood
Artery supplies Vinculi and that is how blood is provided to tendons
Also includes thumb (APL and EPB)
Branch off the common digital artery
There is a short vinculum (vinculum brevis) and a long vinculum (vinculum longus) for each FDS and FDP tendon
The vascular supply is mainly on the dorsal side of the tendons
VBP, VLP, VBS, VLS
Extrinsic Tendon Nutrition: Synovial Fluid
Flexor tendons have a synovial sheath in addition of going through a pulley system
Extrinsic nutrition is provided by synovial fluid diffusion = diffusion is accomplished through MOTION
The flexor tendon sheath is a double-walled fibro-osseous tunnel that is sealed at both ends
Synovial fluid bathes the tendon, which provides nutrition and lubrication for low friction glide
Diffusion occurs as the synovial fluid gets pumped into the tendon fibers during flexion and extension of the fingers (hence, movement is important for tendon healing)
*** Tendons are normally immobilized after procedures, this DOES NOT work with hands (kids may be an exception b/c can’t comply)
Immobilization is NOT good for adults and those who can comply (10 and older) b/c it can create adhesions, patients would eventually start to move and tendons would snap
Hand Pulley System
Annular Pulley System:
* 5 Annular pulleys (A1-A5) that hold the tendons close to the bone
If A2 and A4 aren’t there, can’t keep tendon flesh up against the bone
Pulleys improve the biomechanics efficiency of the flexor tendon system
Key pulleys are A2 and A4
Impairment to the pulley system can cause bowstringing
Bowstringing can contribute to reduction in AROM due to changes in the lever arm of the tendon.
Need to know if pulleys are out b/c you will need to support them
Need to know if they have a nerve injury, if so they will need more flexion
New Surgery = WALENT (wide awake surgery on tendons)
allows surgeon to test glide of tendon and teaches AROM b/c it is super strong
CTR = don’t need flexor tendon retinaculum, can cut and won’t bowstring
Thumb Pulley System
3 Thumb Pulleys:
- A1: located at the level of MP joint
- Oblique: located over the middle of the proximal phalanx MOST IMPORTANT PULLEY
- A2: located at the level of IP joint
Camper’s Chiasm
Adhesions can occur here, where FDP comes through FDS
This is in Zone 2
Gliding affect
5 Flexor Tendon Zones
Zone 1
Zone 1: extends from fingertip to mid portion of middle phalanx
FDP is involved thus can’t bend the tip of the finger
Any injury in this area is known as Jersey finger
Can occur during tackle football
Hx of failure to grab an object
Ring finger commonly involved
Painful swollen finger especially of the solar DIP jt
Inability to bend/flex the tip (distal phalanx)
- X-ray (AP, lateral, oblique) to assess for tendinous rupture or bony avulsion fracture
- Surgical repair required
- Swan position dorsal splint and splint inside
- Immobilization 3-4 weeks for younger for younger
- Rosalyn Evans or Indiana Flexor tendon protocol for adults. Surgical repair should be strong
(4-6 strand core stitch)
Flexor Tendon Zone 2
Extends from the mid portion of the middle phalanx (FDS insertion) to the distal palmar crease
Adhesions reduce excursion and results in a stiff finger
Most common area of flexor tendon laceration
Worst prognosis
Area tends to get cut chopping veggies, carving pumpkin, broken glass (lots of chefs)
Terrible results b/c of Camper’s Chiasm
Gliding of these tendons distal, proximal and against each other is imperative to hand function
It can include just FDS or both FDP and FDS depends on how deep it went
Flexor Tendon Zone 3
Extends from the distal palmar crease to the distal portion of the transverse carpal ligament
Not as much scarring in this area
We don’t see a lot of, it is more in traumatic injuries
Flexor Tendon Zone 4
Overlies the transverse carpal ligament
Area does not scar too bad, more tissue there
Flexor Tendon Zone 5
Extends from the wrist crease to the level of the musculotendinous junction of the flexor tendons
Also known as Spaghetti Wrist
Lots of things in zone 5
suicide attempts
have Nn and big arteries
blood flow and nerve fx big issue
Surgical Tendon Repairs
Incisions: Z plasty
Prone to scarring b/c not a lot of tissue
zig-zag preserves length of tissue, will do anytime there is a crease
Primary Repair = best results, less chance for scarring
within the first 2 weeks of tendon
laceration
the optimal time for tendon repair of flexor tendons is within 24 hours of injury but definitely within 2 weeks the longer the severed tendons have to develop adhesions and scar tissue, the less the possibility of restoring full fx atrophy or tendon shortening occurs
Secondary Repair = for lacerations that were not repaired
soon enough
have a worse prognosis b/c the tendon ends and tendon sheath become scarred the musculotendinous units retract requires tendon graft or 2 stage repair using Huntington rods
The ideal repair is reliable, does not impair healing and is strong
Can’t do passive extension on a repaired tendon
Repair Strength
The strength of the flexor tendon repair is proportional to the number of core suture strands crossing the repair site
Core sutures bring ends together
Epitendinous suture completes the tendon repair - it helps prevent adhesion formation and triggering by sewing up sheath
Type of suture and type of material used contributes to its strength
6-8 strand core sutures doing well and allow for early active motion inside protective dorsal shell splint
2 strands = 0 wks (2500/ 5.5lbs) 6 wks (2700/5.95lbs)
4 strands = 0 wks (4300/9.5lbs) 6 wks (5200/11.5lbs)
6 strands = 0 wks (6000/13lbs) 6wks (7200/15.8lbs)
*** Repair site loses 50% of its strength at end of week one and then starts rebuilding, 33% @ 3 wks and back up by 6 wks
Patient vulnerable btwn wk 1-3
Most ruptures occur btwn day 10-12
Immobilized tendon is 50% weaker day 5-10 than at day one of repair
Ends of a repaired tendon take about 21 days to stick together
Body breaks down suture material unless it is Kevlar and then it starts to heal