Scheker DRUJ Prosthesis
Surgical Demonstration
Images From Two
Cases for Clarity
Demonstrating unstable DRUJ
Demonstrating unstable DRUJ
Demonstrating unstable DRUJ
Forearm in full pronation, 8-9 cm long hockey stick incision along ulnar
border of distal forearm, turning radially just distal to the head of the
ulna for additional 2 cm.
Ioban steridrape or comparable alternative is recommended
to reduce contact between the skin and implant.
Dissection between subcutaneous tissue and the forearm fascia.
Barrier flap design of soft tissue incorporating both fascia and
proximal retinaculum based ulnarward & extending radially to
the second compartment.
Flap elevated from radial to ulnar, incorporating the capsule
present over the head of the ulna for extra cushion.
The ECU Tendon Sheath is Released to Its Distal Origin
The ECU is elevated and it’s tendon sheath is released to it’s distal insertion. This
prevents possible tethering of the tendon against the prosthesis.
The ECU is elevated and it’s tendon sheath is released to it’s distal insertion. This
prevents possible tethering of the tendon against the prosthesis.
EDQM and EIP are elevated from the ulna and interosseous membrane. Extensor
mass is elevated to expose the interosseous crest of radius. The distal posterior
interosseous nerve is divided to prevent avulsion from the extensor mass.
Neck of the ulna is being prepared for osteotomy after the interosseous
membrane is released.
Arthritic Ulnar Head
Interosseous membrane is divided from the crest of the radius.
An elevator is placed volar to the radius and the ulna is levered
volarly to allow exposure of the entire ulnar side of the radius.
The Area of the Sigmoid Notch is Identified
and Any Osteophytes in the area are excised
Volar Lip often requires
contouring for proper
radial plate placement
Improper Dorsally
Angulated Position
Proper Position
Reducing volar lip of radius by means of a saw blade
A Burr can also be used to Contour the Radius for the Radial Plate Trial
The Radial Plate Trial is Positioned on the Ulnar border of the Radius in the Area
of the Sigmoid Notch. Its Volar Facing Edge is aligned with the Volar Surface of
the Radius. Using .045” K-wires the Trial is temporarily fixed to the Radius
The Volar Surface of the Radius is Visualized to Ensure Proper Placement of
the Radial Plate Trial
The Trial’s position is checked using an image intensifer. The PA view
confirms distal clearance and general alignment. The lateral view
ensures the plate is neither dorsally or volarly angulated
The center oval guide hole is drilled first to allow optional final adjustments. Care
is taken to ensure the hole passes transversely through the radius without
violating the dorsal or volar cortex.
The Hole is then Tapped Prior to Introduction of a 3.5 mm Cortical Bone Screw Self
Tapping Screws are NOT used to Allow the Interchanging of Screws if Necessary
With the center screw in place and proper positioning confirmed, the radial peg
drill bit can be passed through the trials distal guide hole. The bit is typically
inserted until its stopping plate contacts the trial. Care should be taken to ensure
the peg bit Does Not violate the dorsal or volar cortex or pass through the radius.
The proximal k-wire is removed and radiographic confirmation used to confirm
final positioning. The profile of the trial with the radial peg bit in place will mimic
what should be seen when it is replaced by the actual prosthesis.
Trial alignment, screw direction - length, radial peg
bit direction and depth are confirmed. If the dorsal
or volar cortex is violated by the peg or screws they
should be removed and redirected.
The Radial Plate is Introduced by first inserting the Radial Plate Peg into the predrilled hole. Care is taken to ensure no tissues are trapped between the plate the
the radius.
A Plastic Impactor is provided to protect the
Radial Plate when using a mallet for insertion
The screw for the oval hole is first applied
followed by up to 4 additional fixation screws
Radial plate positioning checked. Excessive screw length should be
avoided as well as contact between the peg and the distal screw.
The forearm is placed in full pronation (radius at its shortest relative length),
and the ulnar resection guide is inserted along the ulna and into the hemisocket of the radial plate. The ulna is then juxtaposed against the guide.
With the forearm in full pronation, the proximal edge of metal lip below the ball
indicates the appropriate level of resection for a standard length ulnar stem.
Should additional ulna be missing, the resection guide is marked in 1 cm
increments allowing the selection of the appropriate extended ulnar stem.
The osteotomy is made transversely through the ulna
2 mm guide wire is inserted into the ulna’s medullary
canal to act as a centralizing guide.
A cannulated drill bit is inserted over the guide wire, the medullary canal is
drilled to a depth of 11 cm from the distal end of ulna. Care should be taken
to ensure the bit remains within the medullary canal. This is regardless of
the ulnar stem length selected.
A reamer, rounded proximally to prevent misdirection, is
inserted into the canal to cut a Bevel in the distal ulna.
The Reamer is inserted until its Stopping Plate contacts the Distal Ulna
Reaming Complete
Contact with the Ulnar Stem is kept to a minimum during Its insertion
During insertion the ulnar stem will meet resistance as the
plasma spray engages the ulna. A plastic impactor is then used
to protect the distal polished peg of the ulnar stem
Periodically the impactor should be removed and the relationship
between the radial plate and the ulnar stem checked.
Care should be taken not to over insert the Ulna Stem. Regardless of the Ulnar
Stem length used, the distal end of stem should be no more proximal than the distal
end of the Radial Plate. This relationship will provide full support of the UHMWP ball.
The distal Radial Plate and
the distal Ulnar Stem should
be at the same level when
the stem is fully inserted
Standard Length Ulnar Stem
1 cm Extended Length Ulnar Stem
The UHMWP ball is placed over the Distal Peg of Ulnar Stem affectively
replacing the function of the articular surface of the Ulna Head
Demonstrating Range Of Motion
Placement of the Radial Plate Cover, ensuring the mating surfaces are free of
any interposing material and securing it with two small screws completes the
Prosthesis. Care should be taken to firmly secure the screws with out stripping
them. If there is any doubt, replace with new screws. The secured cover
stabilizes the artificial Joint as would an intact TFC in regards to a normal DRUJ.
Adequacy of overall positioning and Screw Length is Confirmed
The Fascial-Retinacular Flap dissected during the approach is identified. This flap
is to be positioned under the ECU and used as a barrier between the prosthesis
and the ECU.
The Fascial-Retinacular Flap under the ECU and over the
prosthesis provides a cushioning barrier for the tendon.
Barrier Flap sutured into position under the
ECU tendon and the EDQM.
With the implant rigidly in place, the skin is closed in a normal
manner, bulky soft tissue dressings are used. Should any doubt exist
as to the implants fixation, a short arm splint should be applied.