dynamic hip screw

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1. How to do Dynamic Hip Screw Dr. Khadijah Nordin

2. Content Introduction Indication Plate Position Reduction Approach Surgical technique Post op management

3. Introduction DHS Design to provide strong and stable internal fixation of variety of intertrochanteric, subtrochanteric and basilar neck fracture with minimal soft tissue irritation. Strong: made from stainless steel and are cold worked for strength Stable: in view of the number of the screw, dynamic compression plate allow angulation of the cortical screw or axial compression and multiple screw fixation

4. Indication Indicating for fracture of the proximal femur: Intertrochanteric fracture Subtrochanteric fracture Basilar neck fracture Indicated for the stable fracture and unstable fracture in which a stable medial buttress can be reconstructed.

5. Plate Plate selection base on: Barrel length: Standard 38mm length Barrel angle: commonly 135 barrel angle The angle that subtended between the femoral neck and shaft axis

6. Positioning The patient is positioned supine with traction table . The ipsilateral arm is elevated in a sling while the contralateral uninjured leg is placed on a leg holder. This position is well suited for excellent true AP and cross-table lateral x-rays.

7. Image intensification An image intensifier is required for reduction on the traction table. With the patient and fluoroscope properly positioned, obtain AP and lateral images.

8. Closed reduction Reduction is usually achieved by first pulling in the direction of the long axis of the leg in order to distract the fragments and regain length. Next comes internal rotation. The reduction must be checked in both the AP and lateral with an image intensifier. In case the closed reduction should fail, open reduction will be necessary.

9. Lateral approach for closed reduction and fixation Incise the skin For insertion of multiple screws, the incision is centred over the femoral neck axis line, and slightly posterior to the palpable mid line of the trochanter. If the soft tissues are thick, the incision may need to be more distal or longer.

10. Surgical technique Reduced the fracture Determine the anterversion by placing the 2.5mm threaded guide wire anteriorly along the femoral neck, using the appropriate DHS guide. Gently hammer the wire into the femoral head This anterversion wire will later allow correct placement of the central guide wire in the center of the femoral head

11. Insert guide wire Align the appropriate DHS angle guide along the axis of the femoral shaft and place it into the femur. Point the guide tube toward the center of the femoral head Predrilling of the lateral cortex with 2.0mm drill bit is recommended in dense bone Insert the 2.5mm threaded guide wire through the appropriate DHS angle guide, parallel to the anteversion wire and directed toward the center of femoral neck.

12. Confirm placement Confirm placement of the 2.5mm threaded guide wire under the II It must lies along the axis of the femoral neck in both AP and lateral view and parallel to the anterversion wire

13. Determine insertion of the length Slide the direct measuring device over the guide wire to determine wire insertion depth. Calibration on the measuring device provide a direct reading

14. Calculate reaming depth and lag screw length To calculate reaming depth, tapping depth and lag screw length, subtract 10mm from the reading Direct reading 105mm Reamer setting 95 Tapping depth Lag screw length 95mm 95mm

15. Reaming to predetermined depth Assemble the appropriate DHS triple reamer Set the reamer to the correct depth Insert the DHS triple reamer to the drive using large quick coupling attachment Slide the reamer over the guide wire to simultaneously drill the lag screw, ream for the plate barrel, and countersink for the barrel junction to the present of the depth

16. Insert lag screw Select the DHS lag screw and assemble the lag screw insertion. Slide the assembly over the guide wire and into the reamed hole. Seat along the centering sleeve over in the hole to center and stabilize the assembly. Insert the lag screw by turning the handle clockwise, until zero mark on the assembly align with the lateral cortex. The threaded tip of the lag screw lies 10mm from the joint surface. The lag screw inserted 5m in porotic bone to increased holding power and additional controlled collapse

17. Align handle Before removing the assembly, align the handle so it is in the same plane as the femoral shaft( parallel to the femoral shaft axis when viewed laterally) This will allow the proper placement of the DHS plate onto the lag screw

18. Removed wrench Removed DHS wrench and long centering sleeve. Slide the appropriate DHS plate onto the guide shaft lag screw until it contact the lateral cortex Loosen and removed the coupling screw and guide shaft Then withdraw the 2.5mm guide wire

19. Seat plate Gently seat the plate with the DHS impactor . Fix plate to femur Fix the DHS to the femur with 4.5mm cortex screws

20. Insert the compression screw The DHS compression screw may be used in unstable fracture to prevent disengagement of the lag screw from the barrel in NWB patient

21. Postoperative treatment Follow up The first postoperative visit is at 6 weeks. Check the position of the fracture with appropriate x-rays. See the patient at six-week intervals until union of the fracture and then as desired.

22. Thank you