GEMINUS ® Surgical Approach

GEMINUS ® Surgical Approach

  • 1. EXPOSURE
    Make an incision ~ 8cm long
    over the course of the Flexor
    Carpi Radialis (FCR) tendon.
    NOTE: The incision should start distally
    at the level of the trapezial
    ridge★, then cross the wrist
    flexion creases in a zigzag
    fashion.

  • 2. RELEASE THE FCR TENDON SHEATH
    Open the sheath of the
    FCR tendon and dissect
    distally past the level of the
    superficial radial artery.

  • 3. CROSSING THE DEEP FASCIA
    Retract the FCR tendon
    ulnarly while protecting the
    median nerve.
    Incise through the floor of the
    FCR tendon sheath distally to
    the level of the trapezium.

  • 4. MID-LEVEL DISSECTION
    Develop widely the
    subtendinous space of
    Parona and expose the
    Pronator Quadratus (PQ)
    muscle.

  • 5. IDENTIFYING THE WATERSHED LINE
    Identify and mark the
    location of the watershed
    line; it is best found by
    palpating for the
    volar rim of the lunate fossa.
    Note:
    The Transitional Fibrous
    Zone (TFZ) is a 1cm wide
    band of fibrous tissue
    located between the
    watershed line and the PQ
    muscle.
    The TFZ must be elevated
    to properly expose the
    radius and for proper plate
    placement.

  • 6. ELEVATING THE PQ MUSCLE
    Incise and elevate the TFZ
    using a scalpel. If necessary,
    develop as an ulnar based
    flap.
    The PQ muscle is frequently
    avulsed from its distal
    attachment to the TFZ. Use
    a periosteal elevator to lift
    the PQ muscle from the
    radius.
    Note:
    The origin of the Flexor
    Pollicis Longus (FPL) muscle
    can be partially released for
    added exposure.

  • 7. THE RADIAL SEPTUM
    The radial septum is a
    complex fascial structure
    formed by the first extensor
    compartment, the insertion
    of the brachioradialis and
    the distal part of the FCR
    tendon sheath.

  • 8. 1st EXTENSOR COMPARTMENT
    Dissect radially to expose
    and release the first extensor
    compartment, then retract
    the abductor pollicis longus
    and extensor pollicis brevis
    tendons.
    Note:
    Protect the radial artery
    and sensory nerve.

  • 9. RELEASE OF THE BRACHIORADIALIS
    Release the insertion of the
    brachioradialis using a step
    cut tenotomy.
    Note:
    The brachioradialis is the
    prime deforming force of
    the distal radius fracture.

  • 10. INTRA-FOCAL EXPOSURE
    Using bone-holding forceps,
    rotate the proximal fragment
    into pronation.
    Note:
    This provides ample
    exposure of the fracture,
    allowing for a thorough
    debridement and provides
    access to articular fracture
    fragments.

  • 11. DEBRIDING THE FRACTURE SITE
    It is necessary to remove
    clot, fibrous tissue and callus
    to achieve a proper
    reduction for complex
    articular or partially healed
    fractures.
    Note:
    Preserve the soft tissue
    attachments to the
    medial aspect of the
    proximal fragment. Here,
    perforators from the anterior
    interosseous artery feed the
    radial shaft.

  • 12. RELEASING THE DORSAL PERIOSTEUM
    In some fractures, it may
    be necessary to release or
    excise the dorsal periosteum
    to achieve a proper
    reduction.

  • 13. INITIAL FRACTURE REDUCTION
    Supinate the proximal radius
    back into place and reduce
    the volar cortex.
    Note:
    Providing traction to the
    hand facilitates in the
    reduction.

  • 14. PROXIMAL PLATE FIXATION
    Position the lunate head
    of the GEMINUS Plate just
    proximal to the volar rim of
    the lunate fossa (watershed
    line).
    Align the proximal portion of
    the plate to the radial shaft,
    then drill through the center
    of the gliding hole using the
    2.5mm bit.
    Measure, and then insert a
    3.5mm compression screw
    (Non Locking Cortical Screw).
    NOTE:
    To avoid contact with flexor
    tendons, the plate must be
    applied just proximal to and
    below the watershed line.

  • 15. PRE-LOADING K-WIRE A.I.M.ING GUIDES
    Select two A.I.M.ing Guides
    and thread them into the
    pre-loaded drill guides at the
    proximal ulnar hole (A) of
    the lunate head, and at the
    most radial hole (B) of the
    scaphoid head.
    NOTE:
    Each A.I.M.ing Guide
    positions the K-wire in the
    axis of the corresponding
    peg.

  • 16. FINAL FRACTURE REDUCTION
    Using the GEMINUS plate
    as a template, apply
    longitudinal traction and
    direct pressure over the
    dorsal aspect of the radius
    to reduce the fracture.
    It is important that the distal
    edge of the plate is flush to
    the surface of the radius.

  • 17. LUNATE FOSSA – PROVISIONAL FIXATION
    First, reduce the lunate
    fossa fragment(s) to the
    lunate head of the GEMINUS
    plate using a 1.5mm K-wire
    through the A.I.M.ing Guide.
    Confirm the proper
    placement of the K-wire at
    the dorsal ulnar corner using
    fluoroscopy.

  • 18. SCAPHOID FOSSA – PROVISIONAL FIXATION
    If present, reduce the
    scaphoid fossa fragment to
    the already reduced lunate
    fossa fragment(s).
    Confirm final fracture
    reduction and placement
    of the K-wires using a 20º
    elevated lateral fluoroscopic
    view.
    Note:
    K-wires also aid in centering
    the plate to the distal
    fragments.

  • 19. PILOT HOLE PREPARATION
    Bend the K-wires out of the
    way to facilitate drill insertion.
    Using the 2.0mm bit, drill
    through the pre-loaded drill
    guide of the medial distal
    hole of the lunate head (A).
    Measure the peg length
    using the Depth Gauge
    taking note of the
    appropriate scale.
    Caution:
    Prevent excessive peg length
    as this can potentially cause
    soft tissue irritation.
    NOTE:
    Each hole must be prepared
    sequentially.
    The Depth Gauge has a scale to reflect measurements either through the pre-loaded drill guides (top scale) or through the Geminus plate (bottom scale).

  • 20. PLATE COMPRESSION
    Remove the pre-loaded drill
    guide using the Peg Driver.
    Insert a Non Locking
    Threaded Peg to compress
    the plate down to the bone.

  • 21. PEG PREPARATION
    Prepare all remaining
    available peg holes and
    insert locking pegs or screws.
    Now remove the K-wires
    and A.I.M.ing guides and
    complete the holes.
    WARNING:
    Use only one High
    Compression Locking Peg or
    Threaded Non Locking Peg
    per head.
    NOTE:
    High Compression Locking
    Pegs help to reduce and
    stabilize dorsal fragments.

  • 22. POLYAXIAL LOCKING SCREW OPTION
    In situations where a peg is
    not optimally positioned, the
    Polyaxial Locking Screw (PLS)
    allows you to insert a screw in
    a desired trajectory different
    to the one determined by the
    plate.
    Please refer to the “Polyaxial
    Locking Screw Surgical Steps”
    section located at the end
    of this surgical technique
    to review the steps and
    instrumentation.
    WARNING:
    Do not use a PLS in the most
    distal hole(s) of the lunate
    head. Use only one PLS per
    head.

  • 23. FINAL DISTAL FRAGMENT FIXATION
    Remove the Threaded Non
    Locking Peg and replace it
    with the appropriate length
    locking peg or screw.
    WARNING:
    Remove ALL pre-loaded drill
    guides and A.I.M.ing Guides.

  • 24. HOOK PLATE EXTENSION OPTION
    The GEMINUS® Volar Plating
    System includes a Hook Plate
    Extension (HPE) to provide
    increased buttressing support
    for Volar Marginal Fragments
    (VMF).
    After the fracture has been
    reduced and fixed with the
    GEMINUS plate, a remaining
    VMF may be noted.
    Please refer to the “Hook
    Plate Extension Surgical
    Steps” section located at the
    end of this surgical technique
    to review the steps and
    instrumentation.

  • 25. PROXIMAL PLATE FIXATION
    Drill through the pre-loaded
    drill guides using the 2.5mm
    bit.
    Measure the screw length using
    the Depth Gauge taking
    note of the correct scale.
    Remove the pre-loaded drill
    guide using the T-10 driver
    and insert the appropriate
    length 3.5mm Cortical
    Locking or compression
    screw (Non Locking Cortical
    Screw).
    Repeat for all remaining screw holes.

  • 26. FINAL RADIOGRAPHS
    Confirm reduction and
    proper peg placement 2mm
    proximal to the subchondral
    plate using a 20º-30º
    elevated lateral fluoroscopic
    view.
    Also confirm that peg and
    screw lengths are correct
    by rotating the wrist under
    fluoroscopy.

  • 27. FINAL APPEARANCE
    Be sure that ALL pegs and
    screws have been fully
    tightened prior to wound
    closure.

  • 28. BRACHIORADIALIS REPAIR
    Repair the brachioradialis
    in a side-to-side fashion to
    serve as an attachment
    point for the PQ muscle.

  • 29. TRANSITIONAL FIBROUS ZONE REPAIR
    Repair the TFZ in order to
    cover the distal edge of the
    GEMINUS plate. This serves
    to further protect the flexor
    tendons.

  • 30. PRONATOR QUADRATUS REPAIR
    Now suture the PQ muscle to
    the repaired brachioradialis
    and TFZ.

  • 31. FCR TENDON REPOSITIONING
    Suture the FCR tendon back
    to its sheath to support the
    distal pole of the scaphoid.

  • 32. WOUND CLOSURE
    Close the incision in your
    normal fashion.

  • 33. OPTIONAL WASHERS
    By using a washer, the
    2.7mm fully Threaded
    Non Locking Peg can be
    used to lag bone fragments
    when necessary.

  • POLYAXIAL LOCKING SCREW (PLS) SURGICAL STEPS
    1. PLATE PREPARATION
    The PLS is designed to be
    inserted over a guide wire to
    assure accuracy.
    Remove the respective
    pre-loaded drill guide from
    the plate.

  • 2. ESTABLISHING DESIRED TRAJECTORY
    Insert the gold end of
    the .9mm K-wire through
    the plate in the desired
    trajectory until the far cortex
    is reached, then confirm the
    desired placement using
    fluoroscopy.
    NOTE:
    The maximum angulation of
    the PLS should not exceed
    10° from the trajectory of the
    respective hole.

  • 3. MEASURING SCREW LENGTH
    Option 1
    Slide the PLS Depth Gauge
    over the K-wire until flush
    against the plate to measure
    screw length.
    Option 2
    The GEMINUS system’s Depth
    Gauge can also be used;
    however, the 0.9mm k-wire
    must first be removed then
    reinserted and confirmed
    for proper placement using
    fluoroscopy.

  • 4. PILOT HOLE PREPARATION
    Drill over the K-wire using
    the 2.0mm Cannulated
    Drill until the far cortex is
    reached, then remove the
    Cannulated Drill, leaving the
    K-wire in place.

  • 5. SCREW INSERTION
    Using the cannulated Initial
    Driver, insert the appropriate
    PLS over the guide-wire and
    into the desired trajectory
    until the head of the PLS
    engages the plate.

  • 6. K-WIRE REMOVAL
    Remove the Initial Driver and
    K-wire

  • 7. LOCKING THE SCREW
    Using the stonger non-cannulated PLS Final Driver, be sure to fully seat and lock the PLS into the plate.

  • 8. FINAL RADIOGRAPHS
    Confirm the proper
    placement of the PLS using
    fluoroscopy.
    Refer to Step 27 for final
    plate fixation and wound
    closure.

  • HOOK PLATE EXTENSION (HPE) SURGICAL STEPS
    1. GUIDE WIRE PLACEMENT
    Advance a 1.5mm K-wire
    through the central HPE
    screw hole (A) located
    on the lunate head of the
    GEMINUS volar plate.
    Cut the K-wire approximately
    1cm above the plate. This
    K-wire helps to position
    the Reduction Tool when
    reducing the volar marginal
    fragment.

  • 2. REDUCING THE VMF
    Slide the slot of the
    Reduction Tool over the
    K-wire.
    Use the hooked tip of the
    Reduction Tool to reduce
    the VMF to the plate.
    NOTE:
    When properly positioned,
    the base of the Reduction
    Tool should be flush to the
    plate with the handle parallel
    to the radial shaft.

  • 3. PILOT HOLE PREPARATION
    While maintaining the
    reduction, drill a 1.5mm
    K-wire through both holes
    of the Reduction Tool.
    Leave the K-wire in place
    within the second drilled
    hole.

  • 4. CONFIRMING REDUCTION
    Using fluoroscopy, confirm
    the reduction, and proper
    placement of the K-wire
    1 – 2mm proximal to the
    subchondral plate.
    NOTE:
    To avoid contact with flexor
    tendons, the HPE must be
    applied proximal to and
    below the watershed line.

  • 5. REDUCTION TOOL REMOVAL
    Remove the cut K-wire from
    the plate.
    While maintaining the
    position of the reduced VMF,
    remove the Reduction Tool
    by sliding it off of the K-wire.
    NOTE:
    Take care not to remove the
    K-wire, as this will allow VMF
    displacement.
    You can mark the pre-drilled
    hole to ease visualization.

  • 6. HPE PREPARATION
    Using a pin cutter, trim
    the distal half of the HPE
    leg that corresponds to
    the remaining K-wire.
    NOTE:
    Cut the leg at an angle to
    facilitate insertion.

  • 7. INITIAL HPE INSERTION
    Use a needle holder to grip
    the HPE by the breakaway
    handling tab.
    Insert the long leg into the
    first pre-drilled hole of the
    VMF.

  • 8. FINAL HPE INSERTION
    Remove the remaining
    K-wire, then insert the short
    leg into the now vacant
    hole.

  • 9. LOCKING THE HPE
    Lock the HPE to the GEMINUS
    plate using the Square Tip
    Driver and an HPE Screw.
    NOTE:
    Ensure that the HPE Screw is
    fully tightened to the
    GEMINUS plate

  • 10. HANDLING TAB REMOVAL
    Now remove the breakaway
    handling tab by lowering
    it toward the radius and
    separating it from the HPE.

  • 11. FINAL FLUOROSCOPIC CONFIRMATION
    Confirm proper placement
    of the HPE using fluoroscopy.
    It should capture the VMF
    with its legs positioned just
    beneath the subchondral
    bone.
    Refer to Step 28 for soft tissue
    repairs and wound closure.