Note: If the ratchet mechanism of the Tibial Proximal Guide does not operate freely, it may be necessary to disassemble, clean, and reassemble the mechanism. If the ratchet mechanism becomes inoperative, it may be removed. The assembly will still function; however, the Locking Bolt may loosen during the procedure.
Verify proper alignment by inserting the 8.0mm Tibial Screw Bushing, the 3.7mm Tibial/Humeral Drill Bushing, and the 3.7mm Drill (Table II) into the appropriate hole of the Tibial Proximal Guide. When the device is properly aligned, the drill will pass through one of the proximal holes and will not contact the nail (Fig.15).
Screw the Threaded Driver or Slaphammer into position on the Locking Bolt. Insert the nail over the Smooth Guide Wire and into the tibia. Begin seating the nail using bentle impaction with the mallet(Fig.16). The nail must advance with each blow of the mallet. If it does not, remove the nail and ream again. While impacting the nail, use the Tibial Proximal Guide to maintain the proper rotation.
Be careful when crossing the fracture site. Visualize the fracture in two planes with image intensification to assure proper passage of the nail into the distal fragment (Fig.17). The conical tip and the bevel of the nail will help guide it off the posterior cortex and maintain its position in the center of the canal (Fig.18). Reduce the force of impaction as the proximal end of the nail approaches the tibial tubercle.
Prior to inserting the nail past the guide wire exit hole, REMOVE THE GUIDE WIRE so it does not get trapped in the bone. Finish seating the nail after the guide wire is removed.
The M/DN Tibial Nail has four proximal locking holes. The two superior holes are angled for fixation in very proximal fracture situations.
The middle hole is a mediolateral dynamic slot to help achieve dynamization. The most inferior mediolateral hole is for static locking. If static locking is preferred, but there is a potential need for later dynamization, insert screws in both mediolateral locking holes. The locking screw in the static hole can then be removed to achieve later dynamization.
If oblique fixation is desired, attach the Tibial Oblique Hole Adaptor to the Tibial Proximal Guide (Fig. 19) so the appropriate''Right''or''Left''indication is up. Secure the adaptor with a set screw, and tighten the screw with the Pin Wrench.
The adaptor has four holes. Two holes are for the left tibia, and two holes are for the right tibia. Use the two top holes. One hole is for anterolateral to posteromedial screw insertion. The other hole is for anteromedial to posterolateral screw insertion.
Tibial Proximal Guide
Tibial Oblique Hole Adaptor
Insert the 8.0mm Tibial/Humeral Screw Bushing through the appropriate hole of the Tibial Proximal Guide or the Tibial Oblique Hole Adaptor until contact is made with the skin. Insert the 3.7mm Tibial/Humeral Drill Bushing (Color Code: Blue), which screws into the Tibial/Humeral Screw Bushing.
Make a small stab wound, then advance the nested bushings through the incision until they contact the medial aspect of the bone (Fig.20). Insert the 3.7mm Drill (Color Code: Blue).
Drill through both cortices (Fig.21). The drill is calibrated to measure the hole depth and determine the appropriate screw length. If desired, the Proximal Screw Depth Gauge can also be used to determine the screw length (Fig.22). Remove the drill and drill bushing.
The 4.2 or 4.5mm screw (Color Code: Blue) is used proximally on all tibial nails. Select the appropriate screw length to ensure that the screw will engage the far cortex.
Use the T-Handle Screwdriver to insert the appropriate length 4.2 or 4.5mm screw until the reference line marked″Tib/Hum″is flush with the bushing (Fig.23&inset). Then use the C-arm to check the position of the screw and tighten it appropriately. Remove the T-Handle Screwdriver and Tibial/Humeral Screw Bushing.
If a second proximal screw will be used, repeat the procedure for the second screw.
Take A/P and lateral C-arm views to check for correct positioning. Disengage the ratchet mechanism, then loosen and remove the Locking Bolt and Tibial Proximal Guide.
END CAP PLACEMENT
Insert an M/DN End Cap of the appropriate length (0mm, 5mm, 10mm ,or 15mm) in the proximal nail. These caps help protect the internal threads of the nail, facilitate future extraction, and allow the surgeon to adjust the length of the nail.
Technique for Using the Free-Hand Targeting Device
The distal locking screws are inserted with a free-hand technique using the Free-Hand Targeting Device. The M/DN Tibial Nail has three distal holes. Two are located for locking in the mediolateral plane, and one is located between the mediolateral holes for locking in the anteroposterior plane.
Note: 6mm tibial nails do not have locking holes distally. 7mm and 8mm nails use 3.7mm screws distally which require a 3.2mm Drill or Trocar (Color Code: Yellow). 9mm-15mm tibial nails use 4.2 or 4.5mm screws distally which require a 3.7mm Drill or Trocar (Color Code: Blue).
Insert the appropriate size Trocar into the Targeting Device and finger tighten (Fig.24). It is very important to properly place the C-arm. Position the C-arm so the locking hole of the nail appears perfectly round on the monitor (Fig.25).
Make a 1cm incision on the lower extremity over the appropriate locking hole. When using the anteroposte-rior hole, be careful to avoid the tendon of the tibialis anterior muscle. Insert the Trocar until it contacts the tibia. Use the C-arm view to center the tip of the Trocar over the locking hole (Fig.26). Then use the C-arm to align the Trocar in the proper axis (Fig.27). Use a small mallet to drive the Trocar into the tibia and through the hole in the nail in line with the x-ray beam. Do not penetrate the far cortex.
Use the Distal Screwdriver to insert the screw through the hole (Fig.31).
Insert the second and third distal locking screws in the same manner (Fig.32). Check the position of all screws with the C-arm in the A/P and lateral planes (Fig.33).
Bushings are available that can be used with the Free Hand Targeting Device. A separate radiolucent Bushing Insert is available to accommodate the bushings.
CLOSURE AND POSTOPERATIVE CARE
After irrigating the wounds, close the proximal wound in layers. Then apply a soft compression dressing.
A short leg splint is used until pain and sweling are decreased. Then early range-of-motion exercises of the knee and ankle are encouraged. Allow toe-touch weight bearing to progress to full weight bearing as fracture callus increases on x-ray films, usually six to eight weeks.
Should extraction of the nail become necessary, attach the Threaded Extraction Adaptor to the end of the nail and use the Slaphammer to extract the nail (Fig.34).
The cannulated Locking Bolt should not be used for nail removal. Extraction of the nail should be accomplished by using the Threaded Extraction Adaptor.
Note: Please refer to the package insert for complete product information, including contraindications, warnings, precautions, and adverse events.