Closed Reduction and percutaneous Pinning - Proximal humerus

Indication

Displaced Proximal humeral fractures.

Anatomy

Axillary nerve.

The axillary nerve runs deep to the deltoid about 6 cm from the acromion and it may lie in the line of approach required for placing screws or wires to secure the greater tuberosity.

It can be avoided by one or all of three methods:
1. The nerve gives off its terminal branches at the level of the lateral end of the acromion. Where the line of fracture permits, the screws or wires should be placed from an anterolateral direction with the arm held in internal rotation.

2. If an approach which avoids the main part of the nerve cannot be avoided, the trocar sheath with the blunt trocar is advanced in a craniomedial direction until bone is met and then slid distally down the bone. The sheath will keep the axillary nerve out of harm’s way.

3. Washers are not used with screws to avoid possible entrapment of the nerve.

Considerations

Considerations for all fractures:

The anaesthesia equipment should be moved to the foot end to allow the c-arm to enter the operative field from superior with the plane of the c-arm parallel to the table's edge.
2 - 2.5mm Terminally threaded K wires/ pins are used for fixation, cut beneath the skin and suture wounds.

Supplementary small fragment (2.7 - 4.0 mm) cannulated screws are used.

Positioning

Beach chair or semi beach chair back elevated 30° to 45°.

Radiolucent table or get arm laterally off table.

Ensure biplanar fluoroscopy possible (II from head end able to do AP and axillary view).

Consider placing patient supine on long bean bag that can be contoured around the scapula, allowing the patient to be moved sufficiently laterally for c-arm visualization.

Confirm imaging and ability to perform closed reduction.

2 Part

In the two-part surgical neck fracture, the pectoralis major acts as a deforming force and displaces the shaft medially and anteriorly, creating an apex anterior angulation.

The arm should first be placed along the patient's side to relax the pectoralis major. If the fragments are impacted, axial traction is performed to disimpact the fracture.

Next, a gentle posteriorly and laterally directed force is applied as the shaft is flexed and brought underneath the head.

Once the reduction is confirmed, the arm is prepared in a sterile fashion and fixation pins are placed under image-intensification control.
Once the fracture has been reduced, a pin is held in front of the shoulder and an image in the anteroposterior plane confirms proper orientation.

A small stab incision is then made, and a straight clamp is used to spread the soft tissue down to the lateral humeral cortex. Two pins are then inserted, from inferior and lateral up into the articular fragment, and biplanar confirmation of proper pin placement is performed.

Next, a third pin is placed from a more anterior and distal orientation.

A fourth pin or cannulated screw may be placed from the greater tuberosity into the shaft especially if there is an undisplaced fracture of the greater tuberosity.

Post operatively 2 part

Patient wears shoulder immobilizer four to six weeks.

Begin pendulum exercises immediately.

When a proximal pin was used to secure a greater tuberosity fragment, no motion is begun until three weeks after the surgery, at which time the proximal pins are removed and pendulum exercises are begun.

Weekly follow up for first two weeks with x rays to ensure pins not prominent as soft tissue swelling subsides and ensure pins not migrating.

Remove pins three to four weeks after surgery.

After the pins have been removed, active motion is commenced.

3 and 4 part

Percutaneous reduction is performed with the help of a pointed hook retractor, an elevator and if necessary a 4 mm Steinmann pin.

In this fracture the head of the humerus may be displaced in internal rotation with anterior and sometimes medial angulation due to the pull of the pectoralis major muscle. The subcapital fracture is reduced with the arm in adduction and internal rotation and, with simultaneous traction applied to the arm, the surgeon uses his thumb to apply counter-pressure posterolaterally in the area of the fracture. The position is then secured by means of three 2 mm K-wires drilled from below through the fragment of the humeral shaft, using threaded pins in elderly osteoporotic patients. The arm is then returned carefully to the neutral position and the greater tuberosity reduced by means of the pointed hook retractor which is inserted into the subacromial space. The greater tuberosity is engaged at the insertion of the supraspinatus tendon and moved anteroinferiorly into the correct position. After temporary fixation with a K-wire the position of the tuberosity is checked by maximum external and internal rotation of the arm, and then fixed by two cannulated titanium screws. When there is pronounced rotational displacement, a Steinmann pin is drilled into the humeral head and used to achieve derotation. When the head is displaced medially and inferiorly, a blunt elevator is advanced from the anterior aspect, following the bone as far as the anatomical neck, and the head segment is then raised. The sliding action along the bone without losing contact presents no threat to the neurovascular structures.

Postoperatively 3 and 4 part

The arm is bandaged lightly against the body for three weeks.

Depending on the degree of stability achieved, passive exercises in the plane of the scapula without rotation begin on the first day after operation.

Remove the pins at three to four weeks.

Rotation and active movement start in the fourth week.

Valgus-impacted 4-part fractures.

Limit surgical exposure as much as possible to preserve blood supply.

However if percutaneous reduction is not possible limited open reduction should be undertaken.

Open reduction is indicated in sub acute fractures and most fractures more than 10 days old.

Steps for percutaneous reduction and internal fixation:

• Percutaneous reduction of the articular segment

• Fixation of the head

• Reduction and fixation of the greater tuberosity

• Reduction and fixation of the lesser tuberosity

Percutaneous reduction of the articular segment

Use a small Cobb periosteal elevator to reduce the humeral head on the shaft through a small incision in the skin.

With the arm held in 20° to 30° of abduction and neutral rotation, (Resch suggests adduction) the level of the intertubercular fracture is identified with fluoroscopy. Generally this is at the junction between the anterior and middle thirds of the head. A 1.5 to 2.0-cm incision is made on the anterolateral surface of the arm over the fracture. Using the image intensifier, advance the elevator towards the impacted articular segment.

The line of fracture between the two tuberosities, which usually lies about 5 mm posterolateral to the intertubercular groove, is located by gently sliding the tip of the elevator over the bone anteriorly and posteriorly.

Pass the elevator between the tuberosities under the lateral portion of the humeral head. 

Elevate/ reduce the head with a superiorly directed force on  the undersurface of the head.

This manoeuvre should be done carefully to avoid over reduction or translation of the humeral head.

In acute fractures, the head usually reduces very easily and stays in the reduced position after the elevator is removed.

Fixation of the head

Once the head fragment is reduced, it is fixed in that position with percutaneously placed 2.5-mm terminally threaded pins. Two retrograde anterolateral pins are usually sufficient. The first pin is placed on the skin, its relationship to the humerus is visualized radiographically, and the entry site is located. The pin enters the arm midway between the anterior and lateral surfaces. After the skin incision is made, a haemostat is used to spread the soft tissues bluntly until the bone is identified. This lessens the risk of injury to the axillary nerve. The pin is placed on the anterolateral surface of the humerus and advanced to within 1 cm of the subchondral surface of the head under fluoroscopic guidance. Accurate pin placement typically requires angling of the pin 45° medially and 30° posteriorly. A second pin is placed parallel and slightly superior or inferior to the first one. At least 1 cm should separate the pins at their site of entry into the bone. Accurate placement of the pins and the quality of the reduction are evaluated by rotating the humerus in a 90° arc of motion while continuously visualizing the humerus under fluoroscopy.
 

Reduction and fixation is not always required for both tuberosities.

This decision is made after reduction and fixation of the head.
 

Reduction and fixation of the greater tuberosity

The greater tuberosity is often found to be anatomically reduced after the head has been reduced. It is held inferiorly by the residual periosteum and superiorly by the rotator cuff. If the tuberosity is anatomically reduced and is stable with motion (as assessed fluoroscopically), it should not need additional fixation. If reduction and fixation of the greater tuberosity is required, a 5-mm incision is made at the midpart of the acromion, approximately 2 to 3 cm distal to the lateral acromial border. A reduction hook or a small elevator is placed through this incision, through the deltoid, and down to the tuberosity surface. The tuberosity is reduced by pulling it forward and slightly distally. A guide-wire from a small (4mm) cannulated-screw set is then placed percutaneously through the greater tuberosity approximately 1 cm inferior to its most superior edge. The guide-wire is then passed across the humerus and into the subchondral bone of the humeral head at an approximately 90° angle with the shaft. Accurate placement of the guide-wire is verified radiographically in two planes (by rotating the humerus). After measurement of the length of the screw, an appropriately sized cannulated screw is placed. A second, parallel screw is placed in a similar fashion approximately 1.5 cm distal to the first. Accurate screw placement is verified fluoroscopically. Beware of the axillary nerve see above.

Reduction and fixation of the lesser tuberosity

The lesser tuberosity is visualized by rotating the c-arm, without moving the humerus. Residual displacement of the lesser tuberosity is better tolerated than is residual displacement of the greater tuberosity; therefore, it is important to visualize these relationships accurately. A nonanatomic relationship between the lesser tuberosity and the articular surface may be misinterpreted as displacement of the tuberosity rather than residual displacement of the head. If the problem is residual displacement of the head, the relationship between the shaft and the lesser tuberosity will be normal, despite displacement between the head and the lesser tuberosity.

Under these circumstances, it is probably better to accept a small (0.5 to 1.0-cm) amount of residual head displacement than to redo the previously placed fixation.

If there is residual displacement of the lesser tuberosity, reduction is achieved with a reduction hook.

The arm is held in 70° of abduction, and the image intensifier aligned for an axial view. A small incision is made and the hook retractor advanced towards the lesser tuberosity, which is then pulled laterally until it is restored to its normal position, that is until the articular incongruity disappears.

Temporary fixation is provided with a K-wire, and one or two cannulated screws are placed anteroposteriorly.

Finally, the K-wires which were initially drilled into the head are cut off under the skin and wounds closed.

Post operatively 4 part valgus impacted

Begin pendulum exercises immediately.

Passive flexion and external rotation with the patient supine are begun during the third postoperative week.

Remove the pins at three to four weeks.

More aggressive passive stretching and strengthening are instituted at six weeks.

References

H. Resch, P. Povacz, R. Fröhlich, and M. Wambacher; PERCUTANEOUS FIXATION OF THREE- AND FOUR-PART FRACTURES OF THE PROXIMAL HUMERUS; J Bone Joint Surg Br, Mar 1997; 79-B: 295 - 300.

Page created by:Lee Van Rensburg

Last updated 11/09/2015