1 Principles topenlarge
Sequence of reduction
- Reduce and fix the tuberosity to the humeral head (thereby converting the 3-part fracture into a 2-part situation).
- Reduce the proximal humeral segment to the shaft with the nail and fix it.
Suture fixation of the lesser tuberosity
Sutures in the subscapularis tendon insertion aid both reduction and fixation of the lesser tuberosity. Once reduced, lesser tuberosity sutures are tied to a similar suture in the infraspinatus tendon for provisional fixation. Ultimately, these sutures contribute significantly to primary stability of the lesser tuberosity.
Lesser tuberosity reduction
Proper reduction of the lesser tuberosity is difficult. Its position is hard to visualize with intraoperative image intensification.
Medial displacement of the lesser tuberosity (A) produces an intraarticular anterior step which can compromise internal rotation.
Lateral displacement of the lesser tuberosity (B) obstructs the bicipital groove and may compromise the bicipital tendon. If possible, correct reconstruction of the bicipital groove is desirable to allow sliding of the tendon. An alternative would be tenodesis of the long head of the biceps.
Reduction of the metaphyseal fracture component
If the entry point has been chosen correctly, insertion of the nail will help reduce the fracture.
Correct nail entrance point
A proper and precise entrance point of the humeral nail is crucial. An incorrect entry site results in malreduction of the metaphyseal fracture.
Preliminary reduction of the fracture helps with identification of the correct nail entry site. K-wire “joy-sticks” (as illustrated) or sutures through the rotator cuff insertions aid with reduction.
Risk of axillary nerve injury
The main structure at risk is the axillary nerve. The axillary nerve should be protected by limiting the incision to less than 5 cm distal to the acromial edge, by palpating the nerve, and by avoiding maneuvers that stretch the nerve during reduction and fixation.
Remember the course of the nerve when placing the distal screws.
Tension band sutures in addition to nail
Sutures placed through the insertions of each rotator cuff tendon increase stability, and should be used as well as the nail and screws, particularly for more comminuted and/or osteoporotic fractures. With osteoporotic bone, the tendon insertion is often stronger than the bone itself, so that sutures placed through the insertional fibers of the tendon may hold better than screws or sutures placed through bone.
These additional sutures are typically the last step of fixation.
2 Reduction and preliminary fixation topenlarge
B1.2 fractures involve the surgical neck of the humerus and the lesser tuberosity.
Sequence of repair:
- Reduce and fix the lesser tuberosity to the humeral head (thereby converting the 3-part fracture into a 2-part situation)
- Reduce the proximal humeral fragment to the shaft and fix it.
If needed, fix the lesser tuberosity with an additional (cannulated) lag screw.
Place rotator cuff sutures
Subscapularis and supraspinatus tendon
Begin by inserting sutures into the subscapularis tendon (1) and the supraspinatus tendon (2). Place these sutures just superficial to the tendon’s bony insertions. These provide anchors for reduction, and temporary fixation of the greater and lesser tuberosities.
Next, place a suture into the infraspinatus tendon insertion (3). This can be demanding, and may be easier with traction on the previously placed sutures, with properly placed retractors, and/or repositioning the arm.
Use of stay sutures
Anterior traction on the supraspinatus tendon helps expose the greater tuberosity and infraspinatus tendon.
Insert a preliminary traction suture into the visible part of the posterior rotator cuff …
… and pull it anteriorly. This will expose the proper location for a suture in the infraspinatus tendon insertion. Then the initial traction suture is removed.
Pearl: larger needles
A stout sharp needle facilitates placing a suture through the tendon insertion.
Reduction of thelesser tuberosity
Direct reduction of the lesser tuberosity fragment is performed by pulling the sutures or, …
… with instruments (eg, elevator) applied either through the incision (as illustrated) or through a separate stab incision.
Preliminary fix the lesser tuberosity
Tighten and tie the transverse sutures in order to preliminarily fix the lesser tuberosity fragment. Thereby, the 3-part fracture is converted into a 2-part situation.
Reduction of the head fragment
Distal traction, perhaps augmented with increased angulation, will help to reduce the fracture.
Use of an elevator
Sometimes, the incision allows insertion of an elevator to disimpact the humeral head, or to help to correct inclination/torsion and to restore a normal relationship of the medial fracture surface. The proximal fragment should be reduced anatomically to the shaft.
The actual process of reduction is done with image intensifier control.
3 Determination of entry point and opening of the canal topenlarge
Determination of entry point
The nail insertion site lies on the axis of the humeral shaft. It is located at the bone-cartilage junction of the humeral head. It is not more lateral on the greater tuberosity. Therefore, a supraspinatus split is necessary.
It is slightly anterior to the center of the greater tuberosity.
Be aware, that the correct entry point depends on the type and design of nail used.
Note: For simplicity, the following illustrations are shown without sutures inserted at the margins of the supraspinatus split.
Insert a K-wire through the correct entry point and confirm proper placement by image intensification.
Open the humerus
The nail entry track passes through or close to the tuberosity fracture plane. Take care not to displace the tuberosity fracture during passage of awl or drill. Ensure that sufficient bone is removed to allow the nail to pass through the reduced fracture. Confirm this at the end of nailing.
A cannulated awl is recommended for opening the proximal humerus. This awl can be inserted over the previously placed guide wire. It should be advanced into the proximal medullary canal.
Pitfall: hidden entry point
If the humeral head is abducted or externally rotated, the entry point is under the acromion. This is typical with varus malaligned fractures.
One has to reduce the humeral head before opening the humeral entry point. A joy-stick technique, as illustrated, is helpful. Alternatively, sutures though the rotor cuff can be used in order to manipulate the humeral head.
4 Nail insertion topenlarge
Mount nail on insertion handle
The humeral nail is mounted on an insertion handle. The nail must be rotated correctly relative to the insertion handle.
If an angled nail is used (as illustrated) ensure that the apex of the nail curvature points away form the insertion handle.
Insert nail and reduce fracture
Insert the nail with slightly rotating movements down to the metaphyseal fracture line. Pass the fracture zone under image intensification and make sure that the nail enters the distal fragment properly.
Make sure the proximal end of the nail is placed beneath the bony surface of the humeral head.
No protrusion of the nail may be tolerated. Confirm with appropriately oriented C-arm images that the nail is below the bone.
The nail illustrated has a transverse spiral blade. At the recommended depth, the spiral blade should lie between the middle and lower third of the humeral head. Depending upon the selected humeral nail, different preoperative planning is necessary for its locking devices.
Be careful not to displace tuberosity fractures when inserting proximal locking components.
Retrotorsion of spiral blade/screw
In order to lock the spiral blade, mount the aiming arm and swivel it approximately 25° anteriorly in order to follow the retroverted axis of the humeral head. (The humeral head axis is directed approximately 25° posteriorly to the condylar plane of the distal humerus.)
Within the humeral head, the spiral blade should be placed at the transition of the middle to the lower third, slightly below the equator.
Mount aiming device and insert trocar combination
Mount the aiming device in the insertion handle. Confirm that the retroversion angle is correct. Make a skin incision for the aiming device, dissect the muscles bluntly down to the bone, and fully insert the trocar.
Insert guide wire
Check once more the retrotorsion of the handle.
Remove the central trocar and drill the guide wire for the spiral blade onto the medial cortex of the humeral head.
The position of the guide wire can be checked under image intensification.
Be aware not to perforate the humeral head in order not to insert a too long spiral blade.
Determine length of spiral blade
Determine the correct length of the spiral blade with the appropriate depth gauge.
Open the lateral cortex
Perforate the lateral cortex with the appropriate cannulated drill.
Insert spiral blade
Attach the spiral blade to the inserter and introduce both over the guide wire.
Align the handle of the inserter parallel to the aiming arm.
The initial rotation of the T-handle of the spiral blade inserter relative to the aiming arm depends on patient anatomy. If the distance from the lateral cortex to the nail is less than 10 mm, start the inserter slightly clockwise from parallel. If the distance from the lateral cortex to the nail is more than 10 mm, start the T-handle slightly counter-clockwise from parallel.
By applying light controlled hammer blows to the connecting screw, advance the spiral blade to the desired depth. This causes the handle to rotate 90°.
Pearl: tension band sutures for the rotator cuff
Place these in the base plate of the spiral blade before the blade is fully inserted.
Monitor the depth of the spiral blade with image intensification. If attaching sutures to the spiral blade, pause when the spiral blade is approximately 1.5 cm to 2.0 cm short of its intended position so that the suture ends can be placed through the appropriate holes in the base blade.
Check position of spiral blade
Check the position of the spiral blade by image intensification.
Pitfall: captured bicipital tendon
If the chosen nail has locking screws that might pass through the bicipital groove, be careful that they do not trap the bicipital tendon.
Drill and determine length of locking screw
For distal locking, insert the two-piece trocar combination (aiming arm). Through an appropriately placed trocar, drill through both humeral cortices until the bit just breaks through the medial cortex, and read the depth from the drill bit. Alternatively, a depth gauge can be used.
Insert a locking screw through the trocar. A second screw is recommended, especially in osteoporotic bone.
Pearl: make one incision large enough to allow palpation of the axillary nerve.
Insert the end cap
The end cap prevents tissue from plugging the inner thread of the nail. Furthermore it offers the option of angular stability, by compressing the spiral blade.
End caps are available in different sizes and can, if necessary, be used to extend the nail. The top of the end cap must not protrude above the surface of the bone.
Supplementary rotator cuff tendon sutures
Rotator cuff tension band sutures are placed using the sutures previously placed in the spiral blade base plate.
Repair rotator cuff
Suture the supraspinatus split.