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  2. Skeleton
  3. Diagnosis
  4. Indications
  5. Treatment

Authors of section


Martin Jaeger, Frankie Leung, Wilson Li

Executive Editors

Peter Trafton

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Nailing (bent nail)

1. Bent vs straight nails

Interference with the rotator cuff footprint

The entry point for a bent nail may go through the bony attachment of the rotator cuff. This bony defect in the footprint cannot be reconstructed later.

The entry point for a straight nail lies under the rotator cuff so the nail is inserted through the rotator cuff. This requires an incision, which should be made in the line of the tendon fibers which can then be closed effectively by a side to side suture.

nailing straight nail

Fixation in osteoporotic bone, fifth anchoring point

Due to the bone density in osteopenic bone straight nails provide a better fixation in the proximal humerus in the region of their entry point. Bent nails run through the greater tuberosity which has a lower bone density compared to the superior humeral head.

nailing straight nail

Interference with fracture lines

In proximal humeral fractures which consist of a fracture of the greater tuberosity the trajectory of bent nails often passes through the fracture line between the greater tuberosity and the humeral head whereas straight nails penetrate the humeral head medial to the fracture line.

nailing straight nail

Fixation pattern of screws

Straight nails run more medial in the axis of the medullary cavity. Therefore, it is possible to perform a direct fixation of the lesser tuberosity through the nail.

nailing straight nail

2. Principles

Correct nail entry point

A precise entry point of the humeral nail is crucial. An incorrect entry site results in malreduction of the metaphyseal fracture.

nailing bent nail

It might be difficult or even not possible to access the correct entry point if the humeral head is displaced severely into a varus position. Therefore, it is strongly recommended to expose the entry point by manipulating the humeral head. K-wire “joy-sticks” (as illustrated) or sutures through the rotator cuff insertions can be used to achieve this.

nailing straight nail

Reduction of the metaphyseal fracture component

If the entry point has been chosen correctly, insertion of the nail will help reduce the fracture.

nailing bent nail

Protection of axillary nerve

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.

In addition, any suspicious screw trajectory should be made to the bone with blunt dissection and checked with finger palpation if necessary.

nailing straight nail

Remember the course of the nerve when placing the distal screws.

nailing bent nail

3. Patient preparation and approach

Patient preparation

This procedure is normally performed with the patient in a beach chair position.



An anterolateral incision is recommended for nailing of proximal humeral fractures. The need for additional access depends upon fracture type. Small separate stab incisions may be used for these fractures.

nailing straight nail

4. Reduction of humeral head

Before opening the humeral entry point reduce the humeral head. A “joy-stick” technique, as illustrated, is helpful.

nailing straight nail

Alternatively, or in addition one can use stay sutures through the tendon of the rotator cuff to manipulate the humeral head.

nailing straight nail

5. Determination of entry point and opening of the canal

Determination of entry point

The nail insertion site is located at the bone-cartilage junction of the humeral head. It is not lateral to the greater tuberosity. 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.

A supraspinatus split may be necessary.

nailing bent nail

Insert a K-wire through the correct entry point and confirm proper placement by image intensification.

nailing bent nail

Open the humerus

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.

nailing bent nail

6. Nail insertion

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 from the insertion handle.

nailing bent nail

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.

nailing bent nail

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.

Depending upon the selected humeral nail, different preoperative planning is necessary for its locking devices.

nailing bent nail

Retrotorsion of locking device

In order to lock the nail in the correct trajectory, mount the aiming arm and swivel it approximately 25° anteriorly in order to follow the retroverted axis of the humeral head. (Due to the physiological retrotorsion of the humeral head, the axis of the humeral head is directed approximately 25° posteriorly to the condylar plane of the distal humerus.)

nailing bent nail

To obtain a true AP view of the proximal humerus, the forearm has to be rotated approximately 25° externally relative to the sagittal plane.

nailing bent nail

Within the humeral head, the spiral blade should be placed at the transition of the middle to the lower third, slightly below the equator.

nailing bent nail

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.

nailing bent nail

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 should be checked under image intensification.

Take care not to perforate the humeral head in order not to insert a too long spiral blade.

nailing bent nail

Determine length of spiral blade

Determine the correct length of the spiral blade with the appropriate depth gauge.

nailing bent nail

Open the lateral cortex

Perforate the lateral cortex with the appropriate cannulated drill.

nailing bent nail

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°.

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.

nailing bent nail

Check position of spiral blade

Check the position of the spiral blade by image intensification.

Pitfall: If the nail has locking screws that might pass through the bicipital groove, be careful that they do not trap the biceps tendon.

nailing bent nail

Insertion of additional head screw

If necessary, an additional 4.0 mm screw can be inserted in the inferior quarter of the humeral head.

nailing bent nail

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.

nailing bent nail

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.

nailing bent nail

Repair rotator cuff

Suture the supraspinatus split.

extraarticular 2 part surgical neck impaction

7. Overview of rehabilitation

The shoulder is perhaps the most challenging joint to rehabilitate both postoperatively and after conservative treatment. Early passive motion according to pain tolerance can usually be started after the first postoperative day - even following major reconstruction or prosthetic replacement. The program of rehabilitation has to be adjusted to the ability and expectations of the patient and the quality and stability of the repair. Poor purchase of screws in osteoporotic bone, concern about soft-tissue healing (eg tendons or ligaments) or other special conditions (eg percutaneous cannulated screw fixation without tension-absorbing sutures) may enforce delay in beginning passive motion, often performed by a physiotherapist.

The full exercise program progresses to protected active and then self-assisted exercises. The stretching and strengthening phases follow. The ultimate goal is to regain strength and full function.

Postoperative physiotherapy must be carefully supervised. Some surgeons choose to manage their patient’s rehabilitation without a separate therapist, but still recognize the importance of carefully instructing and monitoring their patient’s recovery.

Activities of daily living can generally be resumed while avoiding certain stresses on the shoulder. Mild pain and some restriction of movement should not interfere with this. The more severe the initial displacement of a fracture, and the older the patient, the greater will be the likelihood of some residual loss of motion.

Progress of physiotherapy and callus formation should be monitored regularly. If weakness is greater than expected or fails to improve, the possibility of a nerve injury or a rotator cuff tear must be considered.

With regard to loss of motion, closed manipulation of the joint under anesthesia, may be indicated, once healing is sufficiently advanced. However, the danger of fixation loosening, or of a new fracture, especially in elderly patients, should be kept in mind. Arthroscopic lysis of adhesions or even open release and manipulation may be considered under certain circumstances, especially in younger individuals.

Progressive exercises

Mechanical support should be provided until the patient is sufficiently comfortable to begin shoulder use, and/or the fracture is sufficiently consolidated that displacement is unlikely.

Once these goals have been achieved, rehabilitative exercises can begin to restore range of motion, strength, and function.
The three phases of nonoperative treatment are thus:

  1. Immobilization
  2. Passive/assisted range of motion
  3. Progressive resistance exercises

Immobilization should be maintained as short as possible and as long as necessary. Usually, immobilization is recommended for 2-3 weeks, followed by gentle range of motion exercises. Resistance exercises can generally be started at 6 weeks. Isometric exercises may begin earlier, depending upon the injury and its repair. If greater or lesser tuberosity fractures have been repaired, it is important not to stress the rotator cuff muscles until the tendon insertions are securely healed.


Special considerations

Glenohumeral dislocation: Use of a sling or sling-and-swath device, at least intermittently, is more comfortable for patients who have had an associated glenohumeral dislocation. Particularly during sleep, this may help avoid a redislocation.

Weight bearing: Neither weight bearing nor heavy lifting are recommended for the injured limb until healing is secure.

Implant removal: Implant removal is generally not necessary unless loosening or impingement occurs. Implant removal can be combined with a shoulder arthrolysis, if necessary.

Shoulder rehabilitation protocol

Generally, shoulder rehabilitation protocols can be divided into three phases. Gentle range of motion can often begin early without stressing fixation or soft-tissue repair. Gentle assisted motion can frequently begin within a few weeks, the exact time and restriction depends on the injury and the patient. Resistance exercises to build strength and endurance should be delayed until bone and soft-tissue healing is secure. The schedule may need to be adjusted for each patient.

Phase 1 (approximately first 3 weeks)

  • Immobilization and/or support for 2-3 weeks
  • Pendulum exercises
  • Gently assisted motion
  • Avoid external rotation for first 6 weeks

Phase 2 (approximately weeks 3-9)

If there is clinical evidence of healing and fragments move as a unit, and no displacement is visible on the x-ray, then:

  • Active-assisted forward flexion and abduction
  • Gentle functional use week 3-6 (no abduction against resistance)
  • Gradually reduce assistance during motion from week 6 on

Phase 3 (approximately after week 9)

  • Add isotonic, concentric, and eccentric strengthening exercises
  • If there is bone healing but joint stiffness, then add passive stretching by physiotherapist