E-CENTRIX. Ulnar Head Replacement SURGICAL TECHNIQUE

Transcription

1 E-CENTRIX Ulnar Head Replacement SURGICAL TECHNIQUE

2 E-CENTRIX ulnar head REPLACEMENT surgical technique as described by GRAHAM KING, MD University of Western Ontario London, Ontario, Canada

3 E-CENTRIX ulnar head REPLACEMENT as described by Graham King, MD, London, Ontario, Canada general PRECAUTIONS introduction Proper surgical procedures and techniques are the responsibility of the medical professional. Each surgeon must evaluate the appropriateness of the procedure used based on personal medical training and experience. Wright Medical Technology, Inc. cannot recommend a particular surgical technique suitable for all patients. The E-CENTRIX Ulnar Head is designed for primary and revision replacement of a diseased or damaged ulnar head. The eccentric head design provides for accurate restoration of soft tissue tension and hence stability of the DRUJ (distal radial ulnar joint) throughout pronation and supination. Choice of either a 1.5º or 3.0º offset head also allows for improved cosmesis relative to ulnar head excision The roughened head surface encourages soft tissue attachment to stabilize the DRUJ Multiple suture holes can be used to reattach the DRUJ stabilizers at the isometric location on the ulnar head Cobalt chrome heads for optimal wear properties Bone-friendly titanium stems promote ingrowth 20mm stem extender for revision length resection general INDICATIONS benefits Replacement of the distal ulnar head for disorders of the distal radioulnar joint in rheumatoid, degenerative and post traumatic arthritis presenting with the following findings: Pain and weakness of the distal radioulnar joint (not improved by nonoperative treatment) Instability of the ulnar head with radiographic evidence of dislocation or erosive changes of the distal radiolunar joint Failed ulnar head resection (e.g. Darrach resection) Primary replacement after fracture of the ulnar head or neck Revision following failed ulnar head arthroplasty Pain relief of radioulnar impingement and radioulnar instability Restores normal wrist appearance Head made of Colbalt Chrome and stem of Titanium Eccentric anatomical design of the head avoids over-stuffing the joint and restores kinematics Superior stable suture attachment options for TFCC and joint capsule More stem options for better press-fit and revision applications one

4 E-CENTRIX ULNAR HEAD REPLACEMENT SURGICAL TECHNIQUE STEP 1 With the forearm in pronation, an incision is made along the dorsoulnar aspect of the wrist centered over the distal radioulnar joint FIGURE 1. Alternatively a midline dorsal wrist incision can be employed if a concomitant carpal procedure such as a wrist fusion is to be performed or if there is a pre-existing midline incision. Protection of the dorsal cutaneous branch of the ulnar nerve is critical. FIGURE 1 STEP 2 The extensor retinaculum of the fifth extensor compartment is opened to expose the extensor digiti minimi quinti(edmq) which is retracted. The dorsal radioulnar capsule, which lies beneath the EDMQ, is divided exposing the radioulnar joint, while leaving a capsular cuff on the radius for later repair FIGURE 2. STEP 3 The extensor carpi ulnaris(ecu) subsheath and ECU tendon are elevated subperiosteally in a radial to ulnar direction as a capsular flap for later repair. The triangular fibrocartilage(tfc) and ulnar collateral ligament are divided off the distal ulna but remain in continuity with the ECU subsheath. The capsular flap, TFC and collateral ligament form a pocket to support the ulnar head implant. FIGURE 3. FIGURE 2 NOTE The extensor retinaculum should remain intact. The ECU subsheath should not be violated with dissection of the capsule and subperiosteum. Repairs to the ECU subsheath and TFC should be undertaken if there is a defect in the soft tissues. FIGURE 3 STEP 4 Once the ulna head is exposed, elevate the ulnar head dorsally with Hohman retractors carefully placed around the distal ulnar shaft FIGURE 4. FIGURE 4 two

5 E-CENTRIX ULNAR HEAD REPLACEMENT RESECTION External Guide In a primary situation, use the external cutting guide (part # ) to mark the level of head resection. Place the guide end on top of the ulnar head and mark the resection with either a marking pen or bovie. Use a microsaggital saw to resect the ulnar head perpendicular to the ulnar shaft FIGURE 5. FIGURE 5 In a revision procedure or previously removed ulnar head, place the end of the cutting guide at the distal edge of the radial sigmoid notch and using the proximal guide notch, mark the appropriate level of resection for the revision implant FIGURE mm Intramedullary(IM) Guide Using a pointed awl, (part # ) start a hole in the ulnar head fovea near the base of the ulnar styloid. Enter the medullary canal with the starting drill on the handle and manually drill (part # ) to the depth of the mark. Slide the IM cutting guide (part # ) over the drill until it rests on the ulnar head. Use a microsaggital saw to cut a single cortex through the resection slot (primary-distal, revisionproximal) to mark the appropriate level of ulnar head resection FIGURES 7A - 7D. FIGURE 6 FIGURE 7A Revision resection Remove the IM drill and guide to complete the resection of the ulna with a micro saggital saw. FIGURE 7B FIGURE 7C FIGURE 7D three

6 E-CENTRIX ULNAR HEAD REPLACEMENT STEP 5 Using the templating block FIGURE 8, (part # ) measure the head diameter and offset for the correct implant head size. Either the 1.5 or 3.0 mm offset may be chosen FIGURE 9. In the setting of a previous ulner-head excision or a comminuted fracture, radiographic templates of the contralateral ulner-head should be performed. STEP 6 Prepare the ulnar canal with the reamers (part # , , , ) until a tight fit is determined FIGURE 10. FIGURE 8 NOTE If cementing of the stem is planned, use an implant stem one size smaller than measured. 1.5 or 3.0mm Offset STEP 7 Using the stem inserter, (part # ) impact the trial stem lining it up with the mark on the inserter on the ulnar side of the ulna. Assemble the trial head with the appropriate diameter and offset onto the trial stem. With the forearm in full pronation, the marker lines on the trial head should align in a anteroposterior direction to ensure the head is placed in the correct rotation. Ensure the ulnar head articulates at the appropriate height with the sigmoid notch. Revise the level of the ulnar resection if required. A mini-c arm may be used to confirm correct positioning of the trial implant relative to the radius and carpus FIGURES 11 & 12. FIGURE 9 FIGURE 10 FIGURE 11 FIGURE 12 four

7 STEP 8 If the trial reduction is acceptable, the definitive implant stem is impacted into the ulnar canal ensuring a tight fit and the correct rotation using the mark on the ulnar aspect of the stem inserter FIGURE 13. The two suture holes in the stem are also oriented ulnarly. Place the implant head in correct alignment by hand FIGURE 14. The roughened surface of the head is oriented volarly and the articulating surface dorsally with the forearm in full pronation. Firmly impact the head onto stem using head impactor (part # ) and mallet to ensure locking of the morse taper FIGURE15. Implant shown with 20mm extender FIGURE 16. FIGURE 13 FIGURE 14 NOTE In the setting of severe osteopenia or a poor press fit, the stem should be cemented using a standard cementing techniques. A cement restrictor is recommended. Prior to wound closure, the forearm should be rotated through full pronation and supination to ensure accurate positioning of the implant and stability. FIGURE 15 STEP 9 The triangular fibrocartilage complex and ECU subsheath is repaired to the implant stem using non-absorbable (#2-0) sutures FIGURE 17. The stem represents the approximate axis of rotation, facilitating an isometric ligament repair. The dorsal capsule is repaired using non-absorbable(#2-0) sutures and the skin is closed in layers. The repair should permit full supination and pronation, with no instability. Motion that is unobtainable at this time, will not be regained later with physical therapy FIGURE 18. FIGURE 16 Suture Holes STEP 10 The forearm is immobilized in supination post-operatively for three weeks. Active range of motion exercises are then initiated with splinting in supination between exercises for a further three weeks. Passive stretching for terminal rotation begins at 6 weeks and light strengthening exercises are commenced at 8 weeks. Static progressive splinting may be helpful in regaining forearm rotation in those patients who do not demonstrate adequate progress. FIGURE 17 FIGURE 18

8 ORDERING information ULNAR HEADS 596H H H H H H H H x 1.5mm Offset 16 x 3.0mm Offset 18 x 1.5mm Offset 18 x 3.0mm Offset 20 x 1.5mm Offset 20 x 3.0mm Offset 20 x 1.5mm Offset 22 x 3.0mm Offset 2596KITA - IMPLANT KIT ITEM NUMBER DESCRIPTION DESCRIPTION 2 QTY 596H1615 E-CENTRIX ULNAR HEAD 16 X 1.5MM OFFSET 1 596H1630 E-CENTRIX ULNAR HEAD 16 X 3.0MM OFFSET 1 596H1815 E-CENTRIX ULNAR HEAD 18 X 1.5MM OFFSET 1 596H1830 E-CENTRIX ULNAR HEAD 18 X 3.0MM OFFSET 1 596H2015 E-CENTRIX ULNAR HEAD 20 X 1.5MM OFFSET 1 596H2030 E-CENTRIX ULNAR HEAD 20 X 3.0MM OFFSET 1 596S0055 E-CENTRIX ULNAR STEM 5.5MM X 50MM STD 1 596S0065 E-CENTRIX ULNAR STEM 6.5MM X 50MM STD 1 596S0075 E-CENTRIX ULNAR STEM 7.5MM X 50MM STD 1 596S0085 E-CENTRIX ULNAR STEM 8.5MM X 50MM STD 1 596S0100 E-CENTRIX ULNAR STEM EXTENDER 1 ULNAR STEMS 596S S S S S S mm Standard 6.5mm Standard 7.5mm Standard 8.5mm Standard 9.5mm Standard Ulnar Stem Extender 2596KIT1 - INSTRUMENT KIT ITEM NUMBER DESCRIPTION DESCRIPTION 2 QTY E-CENTRIX ULNAR HEAD BROACH 5.5MM E-CENTRIX ULNAR HEAD BROACH 6.5MM E-CENTRIX ULNAR HEAD BROACH 7.5MM E-CENTRIX ULNAR HEAD BROACH 8.5MM E-CENTRIX STEM INSERTER ULNAR HEAD E-CENTRIX HEAD IMPACTOR ULNAR HEAD E-CENTRIX REMOVAL TOOL ULNAR HEAD E-CENTRIX I/M STARTER DRILL ULNAR HEAD E-CENTRIX ULNAR HEAD TRIAL 16 X 1.5MM E-CENTRIX ULNAR HEAD TRIAL 16 X 3.0MM E-CENTRIX ULNAR HEAD TRIAL 18 X 1.5MM E-CENTRIX ULNAR HEAD TRIAL 18 X 3.0MM E-CENTRIX ULNAR HEAD TRIAL 20 X 1.5MM E-CENTRIX ULNAR HEAD TRIAL 20 X 3.0MM E-CENTRIX ULNAR STEM TRIAL 5.5MM E-CENTRIX ULNAR STEM TRIAL 6.5MM E-CENTRIX ULNAR STEM TRIAL 7.5MM E-CENTRIX ULNAR STEM TRIAL 8.5MM E-CENTRIX TRIAL STEM EXTENDER E-CENTRIX EXTERNAL CUT GUIDE E-CENTRIX I/M CUT GUIDE E-CENTRIX 16MM HEAD SIZER E-CENTRIX 18MM HEAD SIZER E-CENTRIX 20MM HEAD SIZER E-CENTRIX HEAD SIZER PLATE SWANSON INTRAMEDULLARY BROACH 1 Wright Medical Technology, Inc Airline Road Arlington, TN phone toll-free Wright Medical Europe SA Rue Pasteur BP Toulon Cedex 09 France phone TM Trademarks and Registered mark of Wright Medical Technology, Inc Wright Medical Technology, Inc. All Rights Reserved. SO R3.07