Lag-screw fixation for Oblique extraarticular or diaphyseal fracture

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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 the spiral fractures, the fracture plane is helical and, 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 no protection plate is necessary.

$Lag-screw fixation of long oblique shaft fracture, indirect reduction by traction, usually unstable, no plate needed.$

A good rule is the following: The fracture line (B) should be at least twice the length of the diameter of the phalangeal diaphysis (A), ie, B ≥ 2A for interfragmentary lag screws to provide sufficient fixation and stability.

$Lag-screw fixation of long oblique shaft fracture, fracture line should be at least twice the diameter of diaphysis.$

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 advantage of a percutaneous reduction and fixation is:

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 an open surgery.

Open reduction and fixation may be used in acute and delayed cases. Addition of a neutralization plate also requires an 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.

$Lag-screw fixation of long oblique shaft fracture, confirm fracture configuration with AP and lateral views.$

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

If the fracture is visible on AP view a lateral approach is used.

If the fracture is visible on lateral view a dorsal approach is used.

Reduction can be achieved by traction and flexion exerted by the surgeon.

Confirm reduction with an image intensifier.

$Lag-screw fixation of long oblique shaft fracture, reduction by traction and flexion, confirm with image intensifier.$

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

$Lag-screw fixation of long oblique shaft fracture, hold reduction with percutaneous forceps, avoid soft tissue impingement.$

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, open the fracture, and irrigate the fracture zone for good direct visualization.

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

$Lag-screw fixation of middle phalanx fracture; rotate finger, open fracture, irrigate zone, determine fracture geometry.$

Direct reduction

Gently use pointed reduction forceps to reduce the fracture anatomically.

Pitfall: excessive pressure may cause fracture comminution.

Confirm reduction under image intensification.

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

$Lag-screw fixation of middle phalanx fracture; gently reduce fracture with forceps, confirm reduction, avoid malrotation.$

Preliminary fixation

Provisionally hold the reduction with either two K-wires, or one K-wire and a reduction forceps. Avoid the planned screw trajectories.

$Lag-screw fixation of middle phalanx fracture; hold reduction with K-wires or forceps, avoid planned screw paths.$

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 the fingers in a degree of flexion, and never in full extension. Malrotation may manifest itself by overlap of the flexed finger over its neighbor. Subtle rotational malalignments can often be judged by tilting 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.

$Lag-screw fixation of middle phalanx fracture; check alignment and rotation in flexion, correct malrotation if present.$

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.

$Lag-screw fixation of middle phalanx fracture; under anesthesia, flex wrist for finger extension, extend wrist for flexion.$

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

$Lag-screw fixation of middle phalanx fracture; exert pressure on forearm muscles to cause passive finger flexion.$

Two screws should be inserted, equally spaced.

$Lag-screw fixation of middle phalanx fracture; insert two screws, equally spaced.$

Screw size

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.

$Lag-screw fixation of middle phalanx fracture; screw diameter determined by fragment size and fracture configuration.$

Insert both screws before fully tightening them.

Insert them as perpendicular as possible to the fracture plane. In spiral fractures, the result is that the screws follow a helical disposition.

Cortical lag screw insertion

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

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

Tendon ruptures around the PIP joint need to be reconstructed with bone tunneling or suture anchoring.

$Lag-screw fixation of middle phalanx fracture; insert screws perpendicular, tighten alternately, avoid fragment displacement.$

Pitfall: countersinking in the metaphysis

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.

$Lag-screw fixation of middle phalanx fracture; avoid countersinking screws in metaphysis to prevent loss of purchase and compression.$

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.

$Lag-screw fixation of middle phalanx fracture; use correct screw length to avoid improper engagement or soft tissue damage.$

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, should be observed if possible.

$Lag-screw fixation of middle phalanx fracture; avoid inserting screws too close to fracture apex, maintain minimal distance.$

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.

$Lag-screw fixation of middle phalanx fracture; check for fissure lines under direct vision, avoid inserting screws through them.$

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 should allow for movement of the unaffected fingers and help with pain and edema control. The arm should be actively elevated to help reduce the swelling.

The hand should be immobilized 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 of the hand and wrist in an intrinsic plus position

The MCP joint is splinted in flexion to maintain its collateral ligaments at maximal length to avoid contractures.

The PIP joint is splinted in extension to maintain the length of the volar plate.

Collateral ligament and volar plate at maximal length

After swelling has subsided, the finger is protected with buddy strapping to neutralize lateral forces on the finger until full fracture consolidation.

$Lag-screw fixation of middle phalanx fracture; protect finger with buddy strapping to neutralize lateral forces until healed.$

Mobilization

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

Follow-up

The patient is reviewed frequently to ensure progression of hand mobilization.

In the middle phalanx, the fracture line can be visible in the x-ray for up to 6 months. Clinical evaluation (level of pain) is the most important indicator of fracture healing and consolidation.

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.