Tendon Injuries and Finger Deformities Flashcards
Apply the concave-convex rule to the MCP/PIP/DIP
Concave distal portion on convex proximal portion = joint surface and bone shaft moving in the same direction.
What type of joint is the DIP?
Hinge type, does flexion and extension
What structures at the digits connect to the Distal Phalanx?
Flexor Digitorum Profundus & Terminal Tendon of the Dorsal Apparatus
What happens anatomically to cause a mallet finger deformity?
Avulsion or laceration of the terminal tendon insertion of the dorsal apparatus.
What would you notice clinically? with Mallet finger
A droop of the distal phalanx of the finger and an inability to extend it.
What is the conservative treatment option? for Mallet finger
Splinting with the DIP in full extension or slight hyperextension x 6 weeks.
What is the non-conservative treatment option? for Mallet finger
Surgical reattachment of the terminal tendon or bony avulsion.
What is the difference between a tendon avulsion and a bony avulsion?
Tendon avulsion involves only the tendon pulley away from or detaching from the bone, versus a bony avulsion when the tendon pulls a chunk of bone away with it. A bony avulsion increases the likelihood that surgery will be needed.
What is something that should be checked at the distal digit with splinting so that further injury is prevented?
Tissue perfusion at the distal digit - make sure blood supply is not being cut off.
Where anatomically does a Boutonniere Deformity occur and what structures are damaged to cause this?
At the DIP joint, causing it to go into hyperextension. This is caused by avulsion or laceration of the central slip of the dorsal apparatus, which in turn causes the lateral bands to slip in a volar direction, eventually pulling the PIP into flexion. A closed avulsion can sometimes take 2-3 weeks to present with the deformity.
What would you notice clinically with Boutonniere Deformity?
Flexion of the PIP with an inability to actively extend it, and hyperextension at the DIP.
What is the Specialty Test for this called
Elson’s Test - Hang fingers off the table and ask the client to extend them at the PIP joint. An inability to do so is a positive test indicating a Boutonniere Injury.
What are the three pathways that a Swan Neck Deformity can occur?
(describe anatomical progression of each)
Untreated or poorly treated Mallet Finger Deformity - laceration or lengthened/lag of terminal tendon causes a laxity of the lateral bands so that they slip dorsally and pull the PIP into hyperextension while the DIP droops into flexion.
Traumatic rupture of the volar plate at the PIP allows the joint to hyperextend and the lateral bands become lax so that the DIP droops into flexion.
Rheumatoid Arthritis erodes the joints in the fingers, enlarging them until the volar plate ruptures causing hyperextension of the PIP and beginning the process listed above.
What would Swan Neck Deformity look like?
DIP flexion and PIP hyperextension.
What is one of the primary treatment concerns after a flexor tendon laceration in the hand?
Adhesions within the flexor sheath is the primary concern.
Anatomically, how do the flexor tendons travel from the forearm to their insertion sites?
Through the carpal tunnel and under the palmar fascia within a synovial sheath, and then into each digit through the flexor tendon sheath within a series of pulleys.
What is bowstringing and what would cause this?
Bowstringing is a pulling away of the flexor tendons from the bones and this is caused by damage to or laceration of the A2 and/or A4 pulleys primarily.
How could an open laceration occur?
Cutting an avocado and trying to take the pit out, the knife could slip and cut the palmar side of the fingers and into the sheath and tendons.