Midaxial approach to the middle phalanx

The midaxial, also known as lateral, approach gives access to the midaxial ligaments, the proximal phalanx, and the proximal and distal end segments.

For management of articular fractures of the head, the incision may need to be enlarged distally.

$Illustration showing midaxial approach to the middle phalanx, accessing midaxial ligaments, proximal phalanx, and proximal and distal end segments. Incision may need to be enlarged distally for articular fractures of the head.$

This approach is indicated for oblique, spiral, comminuted, or transverse fractures of the diaphysis and metaphysis of the middle phalanx.

$Illustration showing midaxial approach to the middle phalanx, indicated for various fractures of the diaphysis and metaphysis.$

AO teaching video

Finger, middle phalanx, lateral approach

Nerve identification

Identify and protect the dorsal sensory branches of the radial and ulnar nerves in the thin subcutaneous tissue.

Illustration of dorsal approaches to the PIP joint, showing identification and protection of dorsal sensory branches of radial and ulnar nerves in thin subcutaneous tissue.

Vein identification

The dorsal venous system of the fingers has longitudinal and transverse branches. Be careful to preserve the longitudinal branches. For better exposure, the transverse branches may be ligated or cauterized but preserve as many dorsal veins as possible to avoid congestion and swelling, with consequent fibrosis and stiffness.

Illustration of dorsal approaches to the PIP joint, showing preservation of longitudinal branches and careful handling of transverse branches to avoid congestion and swelling.

Digital artery and nerve

The digital artery and digital nerve lie palmar to the midaxial line in collateral relation with the flexor tendon sheath.

Preservation of soft-tissue structures

The oblique 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.

Illustration showing midaxial approach to the middle phalanx, preserving or carefully repairing the oblique retinacular ligament of Landsmeer to avoid mallet deformity.

To plan the line of the incision, fully flex the finger as shown and mark the dorsal ends of the flexor creases with dots.

Illustration showing midaxial approach to the middle phalanx, fully flexing the finger and marking dorsal ends of flexor creases with dots.

Extend the finger and connect the dots in a line.

The resulting line is safe for a midaxial skin incision. The digital artery and digital nerve will lie palmar to this line.

Illustration showing midaxial approach to the middle phalanx, extending the finger and connecting dots for a safe midaxial skin incision, with digital artery and nerve palmar to the line.

Make a skin incision from A to B. For further exposure, the incision can be extended proximally.

Illustration showing midaxial approach to the middle phalanx, making a skin incision from A to B, with possible proximal extension for further exposure.

Blunt dissection

Elevate the thin subcutaneous tissues by blunt dissection. Identify and protect the digital vessels and nerve on the palmar aspect, and gently retract them.

The transverse retinacular ligament (TRL) is now exposed.

Illustration showing midaxial approach to the middle phalanx, elevating subcutaneous tissues, protecting digital vessels and nerve, and exposing the transverse retinacular ligament (TRL).

Division of the transverse retinacular ligament

Divide the TRL, using a dental pick inserted between it and the collateral ligament, to avoid accidentally cutting the collateral ligament.

Midaxial approach to middle phalanx, divide TRL with dental pick between it and collateral ligament to avoid cutting ligament.

Exposure of the fracture

Elevate the dorsal fringe of the TRL dorsally with the lateral band to expose the collateral ligament. Retract the palmar remainder of the TRL in a palmar direction, using two fine sutures.

This exposes the fracture extraperiosteally. Elevate the periosteum only immediately adjacent to the fracture line(s).

$Midaxial approach to middle phalanx, elevate dorsal fringe of TRL with lateral band to expose collateral ligament. Retract palmar TRL with sutures to expose fracture extraperiosteally. Elevate periosteum near fracture line.$

Regardless of the chosen approach, all tendon incisions must be repaired with nonabsorbable monofilament sutures with an atraumatic needle prior to wound closure.

Repair the TRL with multiple fine mattress sutures prior to skin closure.

The following suture dimension should be used: