Pre-Operative Planning. Positioning of the Patient

Transcription

1 Surgical Technique

2 Pre-Operative Planning Decide upon the size and angle of the barrel plate to be used from measuring the x-rays. To maximise the sliding action when using shorter lag screws, the Short Barrel plate (25mm) should be considered. In femoral neck fractures the lag screw should rest on the calcar femorale arch with the tip sited in the distal half of the femoral head. In trochanteric fractures the lag screw is placed centrally in the femoral neck and the tip sited in the distal half of the femoral head. With femoral neck fractures a 2 or 3 hole plate will normally suffice. With comminuted trochanteric fractures a 4 hole plate is normally sufficient as longer plate lengths do not add mechanical stability to the fixation of the fracture. Positioning of the Patient The patient should be placed on a fracture table in the supine position. The thighs of both legs should be parallel to the floor, with the healthy limb maintained in abduction. No incision should be made until satisfactory reduction is accomplished with verification by A/P and M/L x-rays using an image intensifier or bi-planar x-ray equipment. The M/L view should show complete correction of external rotation. Complete anatomical reduction or slightly over - corrected (valgus) reduction should be visible in the A/P view. In comminuted fractures reduction of the main fragments of the femoral neck and shaft is attempted along with correct rotation of the limb. The operative site is then prepared in the usual manner with sterile solutions and drapes. The incision is made from the posterior/inferior lip of the greater trochanter and extends distally along the posterior edge of the vastus lateralis. The fascia lata is cut at the posterior edge of the vastus lateralis, which is then elevated anteriorly, and away from the proximal femur. 2

3 Step 1 Using an osteotome, mark on the lateral cortex of the femur the required point of entry for the guide pin. Step 2 A stabilising pin may be placed to prevent rotation of the femoral head fragment in femoral neck fractures. If required, this should be inserted first, and in a parallel plane approximately 12mm superior to the required position of the lag screw guide pin. In the M/L view the tip of the guide pin should be placed in the posterior half of the femoral head. Using the appropriate fixed angle guide, insert the guide pin through the angle guide in the soft tissue anterior to and parallel with the femoral arch. When correct position is achieved on the A/P radiogram, the guide pin is driven into the edge of the femoral head using a power drill. Advance the guide pin to the edge of the subchondral bone. Remove the angle guide. Note: Accurate positioning and insertion of the guide pins is of utmost importance to facilitate this surgical procedure, particularly with the higher angle barrel plates. Check the correct position of the intraosseus guide pin by bi-planar radiograms as this is crucial to the technical results. 3

4 Step 3 The lag screw length is determined by placing the lag screw direct measuring device onto the guide pin ensuring the tip is tight up against the femur. a) If no compression of the fracture is indicated, the required lag screw length will correspond to the reading. b) If compression of the fracture is indicated, the required lag screw length will be the reading minus 5mm in femoral neck fractures, but can be shorter in comminuted trochanteric fractures. Select the required lag screw and place to one side. Step 4 Assemble the calibrated triple reamer to the required depth setting as read from the direct measuring device. Advance the triple reamer over the guide pin until the inferior edge of the hole in the lateral cortex has been countersunk and the drill stop touches the lateral cortex. (The countersink allows the barrel plate to sit tight against the lateral cortex of the femur.) Remove the calibrated triple reamer taking care not to displace the guide pin. 4

5 Step 5 For hard, dense cancellous bone it may be necessary to cut the screw thread with a tap. The small centering sleeve can be mounted on the tap from the side and locked on the shaft of the tap by turning the knurled inner sleeve through 90 degrees. Advance the tap over the guide pin and tap the thread to the same depth as the lag screw. when the full depth has been reached, carefully remove the bone tap without displacing the guide pin. See Steps A - E on Pages 7 & 8 for Optional Technique, which can be used in place of Steps 6-7 below. Step 6 Using the combined plate and lag screw introducer ( & ) both the lag screw and the plate can be manipulated in one step. Insert the introducer coupling screw (470014) into the T handle of the plate/ lag screw introducer (470013). Slide the previously chosen Hiploc barrel plate onto the introducer and then attach the selected Hiploc lag screw into the lugs on the end of the introducer and secure by screwing the introducer screw firmly into the lag screw. The small centering sleeve can then be mounted onto the introducer from the side and secured with the knurled inner sleeve.the whole assembly can then be passed over the guide wire and the lag screw driven home. The lag screw should be advanced until the 0 mark on the wrench reaches the knurled end of the centering sleeve. The lag screw should now be at the lateral cortex. 5

6 Step 7 The T handle of the introducer should be manipulated such that it lies in the same plane as the shaft of the femur. At this point the small centering sleeve should be removed from the shaft of the introducer and the Hiploc barrel plate can be mounted onto the lag screw. The long impactor (470016) should be used to impact the Hiploc plate onto the lateral cortex of the femur. The fracture can now be impacted at this point. To remove the instruments loosen the coupling screw (470014) and remove both the introducer and screw together. The guide wire can now be withdrawn from the lag screw. Step 8 The Hiploc barrel plate should now be attached to the lateral cortex with the appropriate length 4.5mm cortical screws. The 3.2mm drill guide (456460) should be used to drill holes in the neutral position through the plate holes and the depth gauge ( ) employed to ascertain the length of screws needed. 6

7 Step 9 For removal of the screw at a later date: The removal coupling screw is passed down the barrel of the cannulated T wrench (401223). This is used to lock the cannulated T wrench onto the back of the impacted lag screw. The lag screw can then be removed. Notes If compression of the fracture is indicated insert the required compression screw into the back end of the lag screw using a 3.5mm hexagon drive screwdriver. Note: In femoral neck fractures compression should not be applied to patients with osteoporotic bone as the threads tapped in the femoral head can be damaged. In cases of damaged threads a 14mm Super lag screw is available to gain additional purchase. In comminuted trochanteric fractures reduction with bone contact between main fragments can be achieved with the compression screw. Before applying compression remember to release the traction on the leg. In the vast majority of cases the compression screw can be removed at the end of surgery so that it does not protrude into the soft tissue as a result of impaction of the fracture. 7

8 Optional Technique Step A Pass the alignment screw down the guide shaft and into the lag screw. Make sure the alignment lugs in the guide shaft mesh correctly with the slots in the lag screw. Step B Slide the larger centering sleeve onto the cannulated T wrench. The lag screw assembly is then inserted into the T wrench making sure that the lag screw is fully seated. This can be verified by observing the bottom of the lag screw through the hole in the T wrench. Slide the T wrench and lag screw assembly over the centering sleeve into the reamed hole. Begin screwing the lag screw into postion 8

9 Step C Screw the lag screw into the femur until the 0 mark on the wrench reaches the end of the centering sleeve. The lag screw should now be at the lateral cortex. This can be verified visually by sighting the back of the lag screw through the hole in the T wrench Step D Remove the cannulated T wrench. Introduce the previously selected barrel plate over the cannulated barrel guide assembly and advance as far as possible. Remove the cannulated barrel guide assembly. Remove the guide pin. Remove the stabilising pin, if used. Step E Using the barrel plate impactor, drive the barrel plate into the counterbored hole until the plate seats firmly against the lateral cortex of the femur. Refer to Step 8 (page 6) for fixation of plate 9

10 Implants Standard 38mm Barrel Plates 130 Stainless Steel Hiploc CHS - 2 hole hole hole hole hole hole Standard 38mm Barrel Plates 135 Stainless Steel Hiploc CHS - 2 hole hole hole hole hole hole hole hole hole hole hole Standard 38mm Barrel Plates 140 Stainless Steel Hiploc CHS - 2 hole hole hole hole hole hole Standard 38mm Barrel Plates 145 Stainless Steel Hiploc CHS - 2 hole hole hole hole hole hole Standard 38mm Barrel Plates 150 Stainless Steel Hiploc CHS - 2 hole hole hole hole hole hole hole hole hole hole hole For use with 4.5mm Cortical Screws Other Plate Lengths are available on a Made to Order basis 10

11 Implants Short 25mm Barrel Plates 135 Stainless Steel Hiploc CHS - 2 hole hole hole hole hole hole hole Short 25mm Barrel Plates 150 Stainless Steel Hiploc CHS - 2 hole hole hole hole hole hole hole For use with 4.5mm Cortical Screws Other Plate Lengths available on a Made to Order basis. Lag Screws (12.5mm dia.) Stainless Steel Hiploc CHS Lag Screw 12.5 dia x 50mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm Made to order mm mm mm mm mm 11

12 Super Lag Screws (14mm dia.) Stainless Steel mm dia x 50mm made to order mm made to order mm made to order mm made to order mm made to order mm made to order mm made to order mm made to order mm made to order mm made to order mm made to order mm made to order mm made to order mm made to order mm made to order mm made to order mm made to order mm made to order mm made to order mm made to order mm made to order 12

13 Instrumentation Instrumentation Tray Hiploc Guide Pin 2.5 dia x 230mm Pk Hiploc Direct Measuring Device Supraloc - 6 hole drill guide Guide Wire 2.5mm mm Supraloc Reamer Cannulated Drill mm Reamer mm Reamer Angle Guide Angle Guide Angle Guide Angle Guide Angle Guide A28 A Wire 2.0mm x 127mm Instrumentation Tray Hiploc Cannulated Bone Tap Hiploc Guide Shaft Hiploc Alignment Screw Hiploc Cannulated T Wrench Hiploc Wrench Centering Sleeve Hiploc Plate Impactor Hiploc Removal Coupling Screw Plate / Lag Screw Introducer Plate / Lag Screw Introducer coupling screw Tap Centering Sleeve (locking type) Plate Impactor (long) 13

14 Instrumentation Tray mm x 100mm Twist Drill with AO QC mm x 195mm Twist Drill with AO QC mm x 145mm Twist Drill with AO QC mm x 145mm Twist Drill with AO QC mm x 195mm Twist Drill with AO QC Bone Clamp Drill Guide 3.2mm (neutral / compr) AO QC Adaptor AO QC T-Wrench mm Screwdriver with AO QC mm Tufnol Handle Screwdriver mm / 3.2mm Drill Guide mm / 6.5mm Drill Guide mm Cortical Tap mm Cortical Tap Screw Depth Gauge Screw Forceps Instrument Set complete with Instruments Instrument Case only Additional Supracondylar Instruments, available separately Supraloc - 12 hole drill guide Supraloc Reamer Assembly 14

15 Notes 15

16 Notes 16

17 Notes 17

18 Biomet UK Ltd Waterton Industrial Estate Bridgend, South Wales CF31 3XA, United Kingdom Tel Fax: FL T 039 / 09.04