Lag-screw fixation for Oblique extraarticular fracture of the proximal end segment

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Diagnosis
Indications
Treatment

Long oblique/spiral fracture

Treatment of long oblique and spiral fractures is similar. The difference is in the screw insertion in relation to the fracture plane, which is strictly single in the long oblique fractures. In spiral fractures, the fracture plane is helical; therefore, each screw is inserted in a slightly different direction.

Indirect reduction is achieved by traction and digital manipulation. Usually, these fractures are unstable.

In a long fracture, fixation with two or more lag screws is usually sufficient, and a neutralization plate is not necessary.

$Lag screw fixation with two or more screws of long oblique and spiral proximal phalangeal hand fracture$

Short oblique fracture

A short oblique fracture may be stabilized with a lag screw protected with a neutralization plate, ie, condylar or T-plate.

For details, see the dedicated treatment option.

$An oblique proximal phalangeal hand fracture stabilized with a lag screw and protected by a neutralization plate.$

Percutaneous vs open reduction and fixation

For spiral fractures, percutaneous treatment is not an option.

Percutaneous reduction and fixation may be performed with acute oblique fractures.

The advantages of percutaneous reduction and fixation are:

Shorter operation time
Less soft-tissue damage
Faster mobilization

This treatment option needs some skills and experience and special reduction forceps to avoid impingement of swollen soft tissue (atraumatic technique).

If a percutaneous reduction is not achievable, the treatment can be changed to open surgery.

Open reduction and fixation may be used in acute and delayed cases. The addition of a neutralization plate also requires open surgery.

Fracture plane

Obliquity of the fracture is possible either in the plane visible in the AP view or the lateral view. Always confirm the fracture configuration with views in both planes.

$AP and lateral views of oblique extraarticular fractures of the proximal phalanx - hand$

Place the patient supine with the arm on a radiolucent hand table.

Patient positioned supine with the arm on a radiolucent hand table

Fracture obliqueness visible on AP view (in the sagittal plane): A lateral approach is used.

Fracture obliqueness visible on lateral view (in the coronal plane): A dorsal approach is used.

Reduction can be achieved by traction and lateral pressure exerted at the site of maximal displacement.

Confirm reduction clinically and with an image intensifier. If there is shortening of the finger, then there is often malrotation of the fracture.

If the fracture appears stable after reduction, nonoperative treatment can be considered. Confirming reduction with an image intensifier is then essential.

$Traction and lateral pressure exerted at the site of maximal displacement to achieve reduction of a proximal phalangeal hand fracture.$

Hold the reduction with reduction forceps designed for a percutaneous technique. Impingement of soft tissues should be avoided.

$Reduction of an oblique proximal phalangeal hand fracture with reduction forceps.$

If closed reduction is not successful or in a nonacute case, proceed with an open reduction.

When indirect reduction is not possible, this is usually due to interposition of parts of the extensor apparatus.

Fracture visualization

Rotate the finger and open the fracture for good direct visualization.

Determine the exact geometry of the fracture. This is very important for later screw placement.

$Rotation of finger for direct visualization of an oblique proximal phalangeal hand fracture$

Direct reduction

Gently use pointed reduction forceps to reduce the fracture anatomically.

Pitfall: Excessive pressure may cause fracture comminution.

$Application of pointed reduction forceps to reduce and hold an oblique proximal phalangeal hand fracture$

Confirm reduction visually and with an image intensifier.

It is mandatory to confirm that the apex of each fracture fragment has been properly reduced; otherwise, malrotation may result.

$Visual confirmation of the reduction of by checking the apex of the fracture$

Preliminary fixation

Provisionally hold the reduction with either two K-wires or one K-wire and reduction forceps. Be careful to place them in such a way that they will not conflict with later screw placement.

$Two K-wires inserted to provisionally hold reduction of an oblique proximal phalangeal hand fracture$

Identifying malrotation

At this stage, it is advisable to check the alignment and rotational correction by moving the finger through a range of motion.

Rotational alignment can only be judged with flexed metacarpophalangeal (MCP) joints. The fingertips should all point to the scaphoid.

Malrotation may manifest by an overlap of the flexed finger over its neighbor. Subtle rotational malalignments can often be judged by a tilt of the leading edge of the fingernail when the fingers are viewed end-on.

If the patient is conscious and the regional anesthesia still allows active movement, the patient can be asked to extend and flex the finger.

Any malrotation is corrected by direct manipulation and later fixed.

Using the tenodesis effect when under anesthesia

Under general anesthesia, the tenodesis effect is used, with the surgeon fully flexing the wrist to produce extension of the fingers and fully extending the wrist to cause flexion of the fingers.

Surgeon fully flexing the wrist to produce extension of the fingers and fully extending the wrist to cause flexion of the fingers

Alternatively, the surgeon can exert pressure against the muscle bellies of the proximal forearm to cause passive flexion of the fingers.

Surgeon exerting pressure against the muscle bellies of the proximal forearm to cause passive flexion of the fingers

Planning for screw insertion

Each lag screw must be inserted perpendicularly to the fracture plane.

In spiral fractures, the result is that the screws follow a helical disposition.

$Lag screws inserted perpendicularly to the fracture plane for fixation of an oblique proximal phalangeal hand fracture$

If possible, three lag screws should be inserted. Generally, they should be inserted at equal intervals.

$Fixation of an oblique proximal phalangeal hand fracture with two lag screws$

Screw size selection

The exact size of the diameter of the screws used will be determined by the fragment size and the fracture configuration.

The various gliding and thread hole drill sizes for different screws are illustrated here.

Screw sizes of the diameters and thread hole drill sizes

Pearl: smaller peripheral screws

In case a peripheral screw has to be inserted close to the apex of a fragment, use 1.3 mm screws. Keep in mind that the minimal distance to the fracture line must be equal to the diameter of the screw head.

$Peripheral screw insertion with minimal distance to the fracture line must be equal to the diameter of the screw head for an oblique proximal phalangeal hand fracture$

Pitfall: countersinking

Countersinking in the diaphysis should be performed with care as it risks iatrogenic fractures.

Do not countersink the screws in the metaphysis, as its cortex is very thin. If countersinking is attempted, all purchase and compression may be lost due to screw breakthrough.

Countersinking can be performed in the diaphysis not the metaphysis

Screw length pitfalls

Ensure that a screw of the correct length is used.

Too short screws do not have enough threads to engage the cortex properly. This problem increases when self-tapping screws are used due to the geometry of their tip.
Too long screws endanger the soft tissues, especially tendons and neurovascular structures. With self-tapping screws, the cutting flutes are especially dangerous, and great care has to be taken that the flutes do not protrude beyond the cortical surface.

$Correct screw length for fracture fixation means screws should not be too long or too short.$

Pitfall: screw too close to the fracture

Do not insert screws too close to the fracture apex. A minimal distance from the fracture line, equal to the screw head diameter, must be observed.

$Screw placement not close to the fracture apex and with minimal distance to the fracture line equal to the diameter of the screw head$

Pitfall: beware of fissure lines

Often there are short fissure lines that are not apparent on the x-rays. Check for these under direct vision and ensure the screws are not inserted through these fissure lines.

Screws inserted to avoid passing through short fissures

Screw insertion

Insert both screws before fully tightening them.

Cortical lag-screw insertion

Insert them as perpendicularly as possible to the fracture plane.

It is important to tighten the two screws alternately not to displace the fragment.

$Two equally spaced lag screws inserted perpendicularly and tightened alternately in an oblique proximal phalangeal hand fracture$

Final lag-screw fixation with spiral and oblique fracture.

$Final fixation with two lag-screws of a spiral and an oblique proximal phalangeal hand fracture$

Confirm reduction and fixation with an image intensifier.

Postoperative phases

The aftercare can be divided into four phases of healing:

Inflammatory phase (week 1–3)
Early repair phase (week 4–6)
Late repair and early tissue remodeling phase (week 7–12)
Remodeling and reintegration phase (week 13 onwards)

Full details on each phase can be found here.

Postoperative treatment

If there is swelling, the hand is supported with a dorsal splint for a week. This would allow for finger movement and help with pain and edema control. The arm should be actively elevated to help reduce the swelling.

The hand should be splinted in an intrinsic plus (Edinburgh) position:

Neutral wrist position or up to 15° extension
MCP joint in 90° flexion
PIP joint in extension

Dorsal splint to treat a dislocation of the proximal interphalangeal joint

The reason for splinting the MCP joint in flexion is to maintain its collateral ligament at maximal length, avoiding scar contraction.

PIP joint extension in this position also maintains the length of the volar plate.

After subsided swelling, protect the digit with buddy strapping to a neighboring finger to neutralize lateral forces on the finger.

Buddy strapping avoiding direct skin contact with adjacent fingers as conservative treatment

Functional exercises

To prevent joint stiffness, the patient should be instructed to begin active motion (flexion and extension) immediately after surgery.

Follow-up

See the patient after 5 and 10 days of surgery.

Implant removal

The implants may need to be removed in cases of soft-tissue irritation.

In case of joint stiffness or tendon adhesion restricting finger movement, arthrolysis or tenolysis may become necessary. In these circumstances, the implants can be removed at the same time.