Ascension Radial Head Fixation System surgical technique ...€¦ · supination and pronation for isolated fractures of the radial head and neck without ligament injury. This usually

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Ascension® Radial Head Fixation System

surgical technique

table of contents System Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1RADFx K-wire Fixation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2RADFx Compression Screw Technique . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2RADFx Radial Head Plating Technique . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3Modular Radial Head Implant Technique . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5Component Dimensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8Implant & Instrumentation Catalog Numbers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9

radial head fixation systeminstrumentation

MRH LongBroach

MRH Broaches

MRHTrials

MRH HeadImpactor

Starter Awl

MRH StemHolder

MRH Stem Impactor

Resection Guide

Back TableAssembly Pad

CannulatedDrivers

Pick-ups

TissueProtector

K-wires

RADFx CompressionScrews

Non-CannulatedDrivers

Depth Gauge

Pick-ups

Plate Benders

Drill GuideHandle

Drill Guides

RADFx Plates

RADFx Plate Screws

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The Ascension® Radial Head Fixation System combines the features of the RADFx® with our Modular Radial Head and is designed to give the surgeon all the fracture fixation, arthroplasty implants and instruments necessary for radial head fractures. The system is flexible and laid out in a fashion to make it easy to use and understand by the operating room staff.

The Ascension® Modular Radial Head (MRH) system unites flexibility with simplicity – head shape, stem design and size combinations address a broad range of patient anatomy.

The RADFx system includes 0.9mm and 1.2mm K-wires as well as 1.5mm and 2.0mm cannulated compression screws designed to capture bone fragments. The unique cannulated drill and K-wire make the RADFx® compression screw placement accurate and simple. The screws and K-wires can be used in conjunction with the plating system.

The RADFx plate is designed to give the surgeon greater flexibility by providing a fixed angle locking or a non-locking screw. The plate is pre- contoured to approximately match the radius of the proximal radius. Exact match is not necessary with a fixed angle locking plate. When needed, plate benders and drill guides are included to assist with recontouring the plate for improved anatomical fit. The plate comes in two sizes, standard and long. Screws come in lengths of 10-26mm in 2mm increments. All plates and screws are made of titanium alloy.

The RADFx instrumentation is an easy-to-use system which provides surgeons with the tools necessary for open reduction and internal fixation of radial head fractures.

radial head fixation system overview

Plate-bending Irons & Drill Guides

Functional system components:1. K-wires for fracture fixation

and placement of plates.

2. 1.5 and 2.0mm diameter cannulated compression screws.

3. Standard and long radial head fixed-angle locking plates.

4. Radial head implants with 4 stems and 6 head sizes.

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IN CASES OF MASON TYPE 1 OR 2:

Incision and Exposure:Expose the radial capitellar joint using either a posterior or the lateral Kocher approach through the interval between the anconeus and extensor carpi ulnaris muscles. Make a 6-7 cm incision centered on the radial head. Care must be taken to avoid vessels and nerves that pass around the radial neck.

Radiographs will provide for an initial assessment of the fracture. Surgical exposure will indicate the full extent of the fracture and lead to final determination of the surgical approach. The RADFx system provides four modalities of fracture repair or arthroplasty. This surgical technique outlines each modality that can be used individually or in conjunction with each other.

RADFx K-wIRE FIxATION:The RADFx system provides 0.9mm and 1.2mm K-wires for fragment fixation. The K-wires can be delivered using a standard powered wire driver. FIGURE 1.

RADFx COMPRESSION SCREwS:The compression screw system can be used in conjunction with the plating system or on its own. Each compression screw is designed with a variable pitch thread that compresses the fracture fragments together, providing fixation and compression. The mini 1.5mm compression screw should be used for smaller fragments and the high 2.0mm compression screw should be used for larger fragments. Each of these screws is headless and final placement should be slightly below the surface of the bone.

STEP 1: K-wire PlacementUsing a powered driver, advance the 0.9mm K-wire under fluoroscopy, past the fracture line but not through the opposite cortex. FIGURE 1.

STEP 2: Compression Screw PreparationUsing a tissue protector, place the cannulated drill over the 0.9mm K-wire. Advance the drill past the fracture line and check placement under fluoroscopy. Visualize the measurement markings on the drill to determine appropriate screw length. FIGURE 2. These markings are in millimeters. Remove drill and tissue protector, leaving K-wire in place.

Kocher Approach RADFx fixation surgical technique

FIGURE 1

FIGURE 2

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STEP 3: Screw Selection and PlacementUsing the self-retaining cannulated hex driver, select the appropriately sized RADFx compression screw from the compression screw caddy. The screw length is confirmed in the measurement gauge on the compression screw caddy. Insert the compression screw onto the K-wire and advance the screw until the proximal tip is flush with the bone. FIGURES 3, 4. X-ray verifi cation should be performed at this time to confirm proper placement and to ensure the screw has not advanced into the joint space. Remove the screwdriver and K-wire.

RADFx RADIAL HEAD PLATING:STEP 1: Access and Plate SelectionAfter gaining access to the radial head fracture, select the appropriate length plate. The standard plate should address most fractures. The long plate would address distal radial neck or shaft fractures.

STEP 2: Plate PositioningPlace the correct size plate against the head and position plate with two K-wires. FIGURE 5. The plate is positioned opposite the radial ulnar joint and directly lateral with the arm in the neutral position. This position corresponds with the safe zone region to avoid contact with the articulating portion of the proximal radial ulnar joint. The RADFx plate is pre- contoured. Modifications can be made with the Plate Benders to match specific patient anatomy. The attachment of drill guides onto proximal and/or distal screw holes is recommended when plate-bending irons are used. INSET, FIGURE 5.

STEP 3: Fracture Reduction Bone fragments may be reduced in situ with K-wires or RADFx compression screws prior to fixation of plate. FIGURE 6. If fragments cannot be stabilized, they may be assembled on the back table assembly pad using compression screws, K-wires, and the RADFx plate. The reassembled radial head can then be positioned and secured to the radial shaft. FIGURE 7.

STEP 4: Screw PreparationThe three proximal joint line screw holes can accept a fixed-angle or a non-locking screw option. When selecting a locking screw, properly place the drill guide into the first screw hole to be drilled. The locking screws have a fixed

Long Standard

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FIGURE 4

FIGURE 5

FIGURE 6

FIGURE 7

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angle, and care should be taken to avoid screw impinge-ment. FIGURE 8. Using drill guides, drill to the opposite cortex. FIGURE 9. Avoid drilling through the opposing cortex. Remove drill guides and measure the depth of each hole using the depth gauge. FIGURE 10.

STEP 5: Screw Selection and PlacementUsing the standard hex driver, select the appropriately sized screw in the RADFx plate caddy. Screw length is confirmed with the measurement gauge on the screw caddy. Deliver the screw to the corresponding hole. FIGURE 11.

STEP 6: Shaft Screw PlacementRepeat Steps 4-5 for the shaft screws. The oval screw hole should be placed first to allow for reduction and compression of the radial head fracture. This is a non-locking screw.

NOTE: Achieve reduction and compression prior to locking screws.

STEP 7: Final Fixation and AssessmentSecure fragments that cannot be managed by the plate with RADFx compression screws. It is important to fully seat compression screw heads beneath the articular surface to avoid impingement. Assess final range of motion. Confirm proper hardware placement with X-ray. FIGURE 12.

STEP 8: ClosureIrrigate wound prior to closure. Proper care should be taken to repair ligament and soft tissue. Standard closure of the incision should be employed depending on approach taken.

Post-Operative GuidelinesEarly motion can begin in flexion and extension as well as supination and pronation for isolated fractures of the radial head and neck without ligament injury. This usually begins 1-2 days post-operatively. Ligament disruption or further de-stabilization should be handled more conservatively under the guidance of a trained and experienced therapist with specific protocols to address any LCL instability.

Indications• Comminuted radial head fractures with good bone stock

and adequate fracture size.• Intra-articular fractures with significant displacement.• Radial neck fracture with significant angulation or

displacement.• Unstable elbow fracture dislocations with lateral and

medial collateral ligament injuries.

Contraindications• Severe comminution with lack of adequate fracture size.• Any active or suspected infection in or around the joint.• Massive soft tissue swelling.• Physiologically or psychologically unsuitable patient.• Known sensitivity to materials used in this device.• Possibility for conservative treatment.4

FIGURE 8

FIGURE 9

FIGURE 10

FIGURE 11

FIGURE 12

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modular radial head surgical techniqueIN CASES OF MASON TYPE 3 OR 4, REvISION OF ExCISION, OR AN INAbILITY TO PLATE:

Incision and ExposureExpose the radial capitellar joint using the Kocher approach through the interval between the anconeus and extensor carpi ulnaris muscles. Make a 6-7cm incision centered on the radial head. FIGURE 13.

Pronate the forearm during exposure to protect the motor branch of the radial nerve that passes around the radial neck. If needed, release the origin of the anconeus subperiostally and retract it posteriorly to permit adequate exposure of the capsule. Continue the dissection to the joint capsule. Divide the annular ligament (AL) and radial collateral ligaments (RCL) longitudinally along the center-line of the radial head. Reflect the lateral capsule anteriorly and posteriorly to expose the radial head. FIGURE 14.

STEP 1: Resecting the Radial HeadThe radial head resection guide has two resection levels. Inspection of the radial head and trauma to the neck will determine if the standard or long radial head implant will be used. Prior templating of the X-ray will also assist in determining which radial head will be used. Use the normal or long Radial Head Resection Guide to mark the level of the resection.

With one edge of the guide resting on the capitellum, use a surgical marker to mark the resection line on the neck of the radius by resting the tip of the marker against the distal side of the guide while rotating the forearm through supination-pronation. The resulting line should mark a plane that is perpendicular to the pronation-supination axis of the forearm. FIGURE 15. Resect the head holding the saw blade perpendicular to the axis of rotation. FIGURE 16. Reinsert the guide between the capitellum and the resection to ensure a perpendicular cut. FIGURE 17. Avoid excessive resection of the radial head as this may preclude implant placement.

STEP 2: Intramedullary Preparation for Radial Head TrialsThe medullary canal is now prepared for insertion of a radial head trial to assess appropriate size and fit. For unstable elbows, varus stress and rotation of the forearm into supina-tion allows improved access to the medullary canal. For stable elbows with inadequate exposure to access the

FIGURE 13

FIGURE 14

FIGURE 16

FIGURE 17

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FIGURE 15

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medullary canal, careful reflection of the origin of the collateral ligament from the lateral epicondyle may be necessary to permit subluxation to the medullary canal. Enter the canal with the starter awl using a twisting motion. FIGURE 18.

The starter awl should be inserted only 2 cm. The radial head trial has an undersized stem to allow insertion without dislocation of the elbow and for maintaining the integrity of the medullary canal for the final press fit.

STEP 3: Trial ReductionSelect the trial closest in size to, but not larger than, the resected head by inserting and estimating the resected head size with the back table assembly plate. Insert the trial stem into the hole created by the Starter Awl. FIGURE 19.

Assess elbow stability and tracking in forearm flexion, extension, and rotation. An osteotomy that is poorly-aligned will cause the trial to be unstable during the assessment. Be sure to coapt or slightly overlap the dissected capsule edges (previously reflected anteriorly and posteriorly) to assess the fit of the AL around the head of the trial. The edges should meet easily. If the AL cannot wrap completely around the trial, a smaller trial and implant are recommended.

STEP 4: broach the CanalOnce the implant size has been determined, remove the trial and broach the canal. FIGURE 20. Broach progressively up to the selected implant size starting with the smallest sized broach. The broach should be aligned with the pronation-supination axis and perpendicular to the resection.

LonG Stem broAchInGA long stem option can be used in instances where an oblique fracture, revision of an ORIF or primary replace-ment, or if an irrecoverable bone loss has occured distal to the standard or long osteotomy line. The curved stem design can provide optimal stability via improved centralization into the angled canal of the radius.

NOTE: Correct insertion of the long stem broach into the canal is with the bow toward the tuberosity of the radius and the tip point in the direction of the thumb. FIGURE 21.

FIGURE 18

FIGURE 19

FIGURE 20

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FIGURE 21

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FIGURE 22STEP 5: Assembly and ImplantationThere are two options to assemble the stem-head components.

or bAcK tAbLe ASSembLyUsing the back table assembly plate, place the correct size head on the back table assembly plate. The morse taper of the implant stem is inserted into the implant head taper. Place the stem impactor over the stem. The implant taper is seated by firm impaction with a mallet.

Using finger control, insert the prosthesis stem into the prepared hole. It may be necessary to retract the radius to access the canal and allow the head to clear the capitellum. Retraction of the radius can be facilitated with use of a small bone holding clamp. Using the provided head impactor, impact the implant until the collar abuts the osteotomy. FIGURE 22.

In SItu ASSembLyThe Ascension Modular Radial Head can be assembled in situ. Place the correctly sized stem into the prepared medullary canal of the radius. Place the stem holder instrument around the collar of the stem. Using the head impactor instrument, impact the stem into the canal until it is flush with the osteotomy. FIGURE 23. Place the head component on the morse taper of the stem. FIGURE 24. Seat the implant taper with firm impaction using the head impactor. FIGURE 25. Remove the stem holder and impact the implant until flush with the osteotomy.

STEP 6: ClosureA simple closure is sufficient as long as the collateral ligament is not disrupted. Repair the AL and RCL. FIGURE 26. Repair the fascial interval connecting the anconeus and extensor carpi ulnaris muscles. Close the skin. Splint the elbow at 90° flexion and in neutral to full pronation.

Post-Operative GuidelinestrADItIonAL Kocher APProAch:• Place the operated arm in rest in an upper-arm sling

for a period of 4-5 days.• After 4-5 days, gradual mobilization starts within the

comfort zone.• The sutures would be removed at 2 weeks, and formal

therapy would be undertaken in the form of mobilization.• Delay in recovery is dependent on the amount of damage

to and detachment of the extensor muscle mass needed to insert the implant. Mobilization can be delayed depending on the amount of incision to the annular ligament. If the annular ligament was significantly incised, then rehabilitation should proceed slowly to protect the stability of the radial stump.

• If the elbow is considered stable, passive flexion and extension is allowed at 2 days post-op. Both flexion/extension and pronation/supination arcs are permitted without restriction. Active motion can begin by at 5 days.

FIGURE 23

FIGURE 24

FIGURE 25

FIGURE 26

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MRH Head Dimensions (mm) SIzE A b CATALOG NUMbER

20S 20.0 10.9 MRH-350-20S22S 22.0 12.0 MRH-350-22S24S 24.0 13.0 MRH-350-24S20L 20.0 16.0 MRH-350-20L 22L 22.0 17.1 MRH-350-22L24L 24.0 18.1 MRH-350-24L

MRH Stem Dimensions (mm) SIzE A b CATALOG NUMbER

01 17.0 7.6 MRH-350-0102 18.7 8.4 MRH-350-0203 20.5 9.2 MRH-350-0304 40.9 7.6 MRH-350-04

RADFx Plate Dimensions (mm) PLATESIzE A b THICKNESS CATALOG NUMbER

Standard 28 19.6 1.2 501-009-240Long 36 19.6 1.2 501-009-241

RADFx Compression Screw Dimensions (mm) OvERALL LENGTH HEAD IN 2 MM THREAD-TO-THREAD CORE INNERCANNULATION INCREMENTS DIAMETER (T-T) DIAMETER DIAMETER

High 10-26 3.85 2.0 1.0Mini 10-26 3.15 1.5 1.0

RADFx Plate Screw Dimensions (mm) OvERALL LENGTH IN SCREw 2MM INCREMENTS DIAMETER

Locking 10-26 2.7Lag 10-26 2.7

RADFx Drill bit Dimensions (mm) CANNULATED NON-CANNULATED

Outer Diameter (O.D.) 2.0 2.0Inner Diameter (I.D.) 1.0 N/A

IndicationsThe Ascension Modular Radial Head is intended for replacement of the proximal radius for instances of:

• Primary replacement after complex (comminuted) fracture of the radial head.

• Symptomatic sequelae after radial resection.• Axial forearm instability.• Failed silicone radial head implant.• Elbow instability associated with radial head fracture

or excision of the radial head.• Replacement of the radial head for degenerative or

post-traumatic disabilities presenting pain, crepitation and decreased motion at the radiohumeral and/or proximal radio-ulnar joint.

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Contraindications• Bone musculature, tendons or adjacent soft tissue

compromised by disease, infection or prior implantation, which cannot provide adequate support or fixation for the prosthesis.

• Any active or suspected infection in or around the joint.

• Skeletal immaturity.

• Physiologically or psychologically unsuitable patient.

• Known sensitivity to materials used in this device.

• Possibility for conservative treatment.

component dimensionsb

A

Diameter

b

A

b

A

b

A

T-T

Core Diameter

Screw Diameter

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radial head fixation systemcatalog numbersrADFx Implants SIzE / COMPONENT CATALOG NUMBER

High Compression Screw, 2.0 x 10 mm 519 010 150









Mini Compression Screw, 1.5 x 10 mm 515 010 070









Radial Head Plate, Standard 501 009 240

Radial Head Plate, Long 501 009 241

Plate Locking Screw, 2.7 x 10 mm 28.25.010









Plate Lag Screw, 2.7 x 10 mm 28.25.110









rADFx Disposables ITEM / DESCRIPTION CATALOG NUMBER

K-wire 0.9 x 105 mm 609 090 105

K-wire 1.2 x 100 mm 605 120 100

Drill Bit 502 015206

rADFx Instruments ITEM / DESCRIPTION CATALOG NUMBER

RADFx Complete Instrument Set INS-RADFX

RADFx Compression Screw Set INS-860-00

Pick-ups 503 004197

Micro Cannula Drill w/Depth Gauge 503 006320

Tissue Protector 503 006343

TX 6 Cannulated Driver 503 004267

TX 8 Cannulated Driver 503 004270

Cannula Mallet Plug (Tap) 503 004331

RADFx Plate Instrument Set INS-870-00

Plate Bending Iron PBI-800-00

Drill Guide Handle 503 004157

Screw-on Drill Guide 503 004170

TX 8 Non-cannulated Driver 503 004268

Depth Gauge for Plate Screws 503 004262

modular radial head (mrh) Implants SIzE / COMPONENT CATALOG NUMBER

20mm standard head MRH-350-20S



20mm long head MRH-350-20L



01 standard stem MRH-350-01



04 long stem MRH-350-04

modular radial head Instruments ITEM / DESCRIPTION CATALOG NUMBER

MRH Instrument Set INS-350-00

MRH Resection Guide OSG-350-01

Starter Awl AWL-100-01

MRH Trial Size 20 Standard TRL-351-20S



MRH Trial Size 20 Long TRL-351-20L



MRH Broach Size 01 BRH-300-20




MRH Back Table Assembly Pad IMP-350-01

MRH Head Impactor IMP-300-00

MRH Stem Holder EXT-350-00

MRH Stem Impactor IMP-350-00

At Ascension Orthopedics, we are dedicated to transforming the surgical experience.

Ascension Orthopedics, Inc.8700 Cameron RoadAustin, Texas 78754

[email protected]

512.836.5001 Ph 877.370.5001 TFP 512.836.6933 Fax 888.508.8081 TFF

Caution: U.S. federal law restricts this device to sale by or on the order of a physician.

LC-04-357-003 rev E©2009

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Ascension Radial Head Fixation System surgical technique ...€¦ · supination and pronation for isolated fractures of the radial head and neck without ligament injury. This usually

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