PATIENT POSITIONING AND RADIOGRAPHIC CONTROL

Place the patient in the "beach chair" position with the operative shoulder slightly over the edge of the operative table (Fig. 2). The back should be angled at 45 degrees. Flex the patient at the hip with the foot lowered 20 degrees. Slide the patient to the side of the table so that the shoulder overhangs the table at the level of the scapula. Place a small sandbag beneath the shoulder for elevation.

Place the image intensifier above the arm so that, with the arm abducted, a clear anteroposterior and lateral view of the fracture can be obtained by rotating the image intensifier and the patient's arm. The proximal humerus should also be visible on the image intensifier.

REDUCTION

It is important to reduce the fracture before beginning the surgical procedure.

INCISION AND EXPOSURE

Begin the incision at the anterolateral aspect of the shoulder at the level of the acromion and extend it about 3cm distally (Fig. 3). Carry the dissection sharply down through the skin and subcutaneous tissue to the border of the acromion. Continue to the lateral aspect of the acromion in its anterior third. Expose the edge of the acromion and split the deltoid. Adduct the arm across the chest to expose the greater tuberosity. Palpate the greater tuberosity and make an incision in the rotator cuff at the insertion of the rotator cuff longitudinally approximately 2cm. This should expose the superior aspect of the articular cartilage of the humerus and the insertion of the rotator cuff in the greater tuberosity.

CREATING THE ENTRY PORTAL

Place the Femoral or Tibial Awl at the junction of the articular cartilage and the greater tuberosity (Fig. 4).

Check the position with A/P and lateral views. When the correct position is achieved, rotate the awl to create an entry portal for the Bulb-tipped Guide Wire.

GUIDE WIRE PLACEMENT AND REAMING

Attach the 3.0mm Bulb-tipped Guide Wire to the Wire-Grip T-Handle (Fig. 5) and tighten.

To aid in manipulation, bend the tip of the guide wire at about a 10°-15° angle 2cm from the end (or use a pre-bent guide wire).

Insert the guide wire through the entry hole and manipulate it down the proximal humerus.

Advance it to the edge of the proximal aspect of the fracture site and use the C-arm to assure proper placement.

Optional Technique: The 2.4mm bulb-tipped guide wire in 70cm length can be used as an alternative to the standard 3.0mm guide wire (100cm length).

Position the arm to the side of the patient and place traction on the arm to align the humeral shaft. Manipulate the guide wire into the distal fragment under C-arm control (Fig. 6). Then advance the guide wire into the center of the epicondylar region of the humerus (Fig. 7). Remove the Wire-Grip T-Handle.

Determine the proper nail length by placing a second guide wire of equal length at the point where the first guide wire enters the proximal humerus. The length of the wire that is not overlapping is the correct nail length required (Fig. 8).

An alternative method is to place a clamp on the calibrated bulb-tipped Guide Wire at the point where the wire enters the proximal tibia and read the length from the calibration marks.

Place the Skin Protector in the wound. Then place an intramedullary reamer over the guide wire and ream the humeral canal. Continue reaming in 1/2 millimeter increments until contact is made with the cortical wall. Ream the humeral canal an additional 1mm larger. The diameter of the humeral nail selected should be 1mm less than the largest reamer used. Humeral nails from 6mm to 10mm have an 11mm proximal body. Overream to 12mm for these nails (approximately 50mm in length).

Caution: In a comminuted shaft fracture, do not ream across the area of comminution. Ream only in the solid aspect of the shaft. Avoid reaming when there is injury to the radial nerve.

When the  reaming is complete and the final measurements are made, insert the plastic Exchange Tube over the Bulb-tipped Guide Wire.

Remove the Bulb-tipped Guide Wire and insert the 2.4mm Humeral Smooth Guide Wire (Fig. 9).

Note: 6mm and 7mm nails are solid and, therefore, the  guide wire must be removed before nail insertion. You must use a 2.4mm Guide Wire with all Humeral Nails.

NAIL INSERTION

Attach the selected nail to the Humeral Proximal Guide, making sure that the arrows align. A keyway in the proximal end of the nail will help ensure proper alignment (Fig. 10). Lift and turn the ratchet lever 90 degrees to open the ratchet mechanism of the Humeral Proximal Guide. Insert the locking Bolt through the barrel of the guide (Fig. 11). Lift and turn the ratchet lever 90 degrees to close the ratchet mechanism, and use the Pin Wrench to tighten the Locking Bolt into the proximal end of the nail. The ratchet mechanism will prevent the bolt from loosening during insertion of the nail.

Note: If the ratchet mechanism of the Humeral 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.

Note: All humeral nails use 4.2 or 4.5mm screws proximally which require a 3.7mm Drill (Color Code: Blue).

Verify proper alignment by inserting the 8.0mm Tibial/Humeral Screw Bushing, the 3.7mm Tibial/Humeral Drill Bushing (Color Code: Blue),and the 3.7mm Drill (Color Code : Blue) (Table II) into the appropriate hole of the Humeral Proximal Guide. When the device is properly aligned, the drill will pass through one of the proximal holes and will not contact the nail.

Screw the Threaded Driver or Slaphammer into position on the Locking Bolt. Insert the nail over the 2.4mm Smooth Guide Wire and into the humerus.

Begin seating the nail using gentle impaction with the mallet (Fig. 12). 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 Humeral 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 he nail into the distal fragment (Fig. 13). Reduce the force of impaction as the proximal end of the nail approaches the humeral head. Nail should be inserted 5mm below subchondral bone.

When the nail is fully seated, REMOVE THE GUIDE WIRE so it does not get trapped in the bone. Remember, it might be concealed inside the driver of Slaphammer.

PROXIMAL LOCKING

The M/DN Humeral Nail has three oblique locking holes proximally.

Insert the Tibial/Humeral Screw Bushing through the hole of the Humeral Proximal Guide until contact is made with the skin. Insert the 3.7mm Tibial/Humeral Drill Bushing (Color Code: Blue), which screws into the screw bushing. Make a small stab wound, then advance the nested bushings through the incision until they contact the bone (Fig. 14). Insert the 3.7mm Drill (Color Code:Blue). Drill through both cortices (Fig. 15). 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. 16).

Use the T-Handle Screwdriver to insert the appropriate 4.2 or 4.5mm screw (Color Code: Blue) to the correct hash mark (Fig. 17). Insert the screw until the "Tib/Hum" reference line is flush with the bushing. Be careful not to drive the head of the screw through the lateral aspect of the humerus. Remove the T-Handle Screwdriver and Tibial/humeral Screw Bushing.

For more proximal fractures, additional oblique screws may be used. Attach the humeral Oblique Hole Adaptor to the Humeral Proximal Guide (Fig. 18). Secure the adaptor with a set screw, and tighten the screw with the Pin Wrench. The adaptor has two holes. One hole is for anterolateral to posteromedical screw insertion. The other hole is for posterolateral to anteromedial screw insertion.

Insert the 8.0mm Tibial/Humeral Screw Bushing through the appropriate hole of the Humeral Oblique Hole Adaptor until contact is made with the skin. Insert the 3.7mm Drill (Color Code: Blue). Drill through both cortices (Fig. 19). Determine the screw length by using the calibrations on the drill. Select a screw 5mm shorter than measured to avoid penetration of the head. Remove the drill and drill bushing.

Use the T-Handle Screwdriver to insert the appropriate length 4.2 or 4.5mm screw (Color Code: Blue) until the reference line marked "Tib/Hum" is flush with the bushing (Fig. 20). 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 an additional proximal screw will be used, repeat the procedure.

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 Humeral proximal Guide.

Be sure that the humerus has not been distracted during nail insertion and proximal locking. Before locking the nail distally, tap on the elbow or the insertion device to ensure impaction.

The proximal portion of the M/DN Humeral Nail also has three suture holes which allow the use of 1.3mm Cable-Ready^® Cable with needle or suture wire to capture humeral head fragments and the rotator cuff.