- Dorsal approach to the DIP joint
The dorsal approach to the distal interphalangeal (DIP) joint is indicated
for extensor tendon avulsion fractures of the dorsal base of the distal
phalanx, or intraarticular fractures with palmar dislocation.
It is also indicated for DIP arthrodesis.
Note the crisscross alignment of the fibers within the conjoint extensor tendons, and also within the triangular ligament.
Damage to the nail matrix must be avoided, since it may cause permanent deformity of the nail.
There are three common skin incisions: The H-shaped, the Y-shaped, and the
lazy S-shaped incision.
The H-shaped incision is usually modified by diverging the sides slightly, to improve vascularity.
An alternative incision, designed to reduce potential soft tissue trauma, is a simple transverse incision, which will give enough exposure for osteosynthesis or for joint surface preparation for arthrodesis.
Elevate the skin flaps
Depending on the shape of the skin incision, flaps should be elevated and
held with fine sutures to minimize soft-tissue trauma.
Tiny veins will appear, and should be coagulated with the bipolar forceps, as necessary, to gain exposure of the joint.
Division of the extensor tendon
Divide the terminal extensor tendon with either a transverse tenotomy, a
step cut, or a long oblique cut.
The step cut and the oblique cut facilitate repair.
Preserve the Landsmeer ligament
The retinacular ligament of Landsmeer passes obliquely from the palmar
aspect at the attachment of the A3 pulley to the terminal conjoint extensor
tendon. This ligament must be preserved to avoid a mallet deformity.
If it proves necessary to divide this ligament, it must be repaired carefully.
Expose the joint
Retract the terminal extensor tendon proximally, in order to expose the DIP joint.
Repair the extensor tenotomy with multiple fine nonresorbable mattress sutures.