Surgical Procedures
10.1 Overview
Uncomplicated fracture healing after open reduction and internal fixation requires stable fixation. Only then does the advantage of operative therapy become apparent, namely, early active motion stability.
Secondary fracture healing is achieved with closed reduction and fixation using percutaneous operation methods, which usually require additional temporary postoperative external immobilization or an external fixator.
The following are commonly employed operation methods:
Wire suture
Tension band wiring
Lag screw(s)
Lag screw plus neutralization plate
Percutaneous lag screw
Plate fixation:
Standard plate
Dynamic compression plate
Hybrid plate
Fixed-angle locking plate
Condylar plate
Intraosseous compression:
Intraosseous screw, headless bone screw (HBS)
Intraosseous compression wire
Intramedullary Kirschner wire or pin
External fixator
Adaptive fixation:
Percutaneous Kirschner wire fixation
Hooked wire
Plugging method
Retrograde wire drilling
Ishiguro operation / extension-block pinning
Transfixation
Temporary joint transfixation
Dynamic distraction external fixation
Pull-out barbed wire suture / Lengemann
Hooked plate
Absorbable pins
10.2 Wire Suture
10.2.1 Procedure
Drill two holes, approximately 1 cm proximal and 1 cm distal to the fracture gap, transverse to the shaft axis (Fig. 10.1a)
The drill holes should be dorsal to the long midlateral axis ( ▶ Fig. 10.1b) with a diameter of 1 mm.
Thread two wires (diameter 0.8 mm) through the holes.
Twist the wires together at the level of the fracture ( ▶ Fig. 10.1d), tightening them equally on both sides.
Practical Tip
Pass a size no. 1 needle through the drill hole and introduce the 0.8-mm wire into the tip of the needle. Advance the wire and withdraw the needle ( ▶ Fig. 10.1c)
Fig. 10.1 Wire suture. (a) Two holes are drilled transversely to the shaft axis, 1 cm proximal and 1 cm distal to the fracture. (b) The drill holes are dorsal to the long axis of the bone. (c) A sufficiently large needle is pushed into the hole, the wire is pushed through the needle, and the needle is removed. The procedure is repeated in the second hole. (d) The two wires are twisted together at the level of the fracture by pulling evenly on both at the same time.
10.3 Tension Band Wiring
Principle When fractures are located in the area of bending forces, tension band wiring can generate interfragmental compression on loading. The fixation material must be placed on the side exposed to tensile forces. Compression is then produced on the bending side. By means of this interfragmental compression, the fracture usually heals.
Application Tension band wiring—applied to the extensor side in the middle third—is effective for transverse fractures of the metacarpals. Tension banding is also useful for avulsion and traction fractures. In this case, the fixation neutralizes the pull of the tendons on the avulsed fragment. The method is used most frequently for intra-articular avulsion fractures such as the type III Busch fracture of the proximal end of the distal phalanx and intra-articular fracture of the base of the fifth metacarpal.
10.3.1 Shaft Fractures
Drill two holes transversely, approximately 1 cm proximal and 1 cm distal to the fracture gap ( ▶ Fig. 10.2a).
The drill holes are palmar to the long midlateral axis, diameter 1 mm ( ▶ Fig. 10.2b).
Thread two wires (diameter 0.8 mm) through the holes using a size no. 1 needle.
Draw one of the wires along the extensor side of the bone on the periosteum palmar to the extensor tendon to the contralateral hole located beyond the fracture ( ▶ Fig. 10.2c).
Caution
Handle the extensor tendon gently.
Cross the two halves of the wire over the extensor surface of the phalanx on the periosteum palmar to the extensor tendon; exert steady tension on the ends of the wires until they lie flat on the bone ( ▶ Fig. 10.2d).
The ends of the first wire are twisted together with the ends of the second wire with steady tension distal or proximal to the fracture gap ( ▶ Fig. 10.2e).
For additional fracture stabilization, a Kirschner wire may be inserted obliquely, diameter 1 mm ( ▶ Fig. 10.2f), but only after completing the tension band wiring. This is usually not necessary, however.
Fig. 10.2 Tension band wiring of a shaft fracture. (a) Two holes are drilled transversely to the shaft axis, approximately 1 cm proximal and 1 cm distal to the fracture. (b) The drill holes are located palmar to the long axis of the bone. (c) Two wires are threaded through the drill holes (see tip in Chapter ▶ 10.2.1). (d) One tension band wire is pulled through in a cruciate pattern to the contralateral drill hole, dorsal to the fracture but palmar to the extensor tendon and lying directly on the periosteum. (e) The ends of the wires are twisted together proximal or distal to the fracture under steady traction. (f) If the tension banding is not stable enough, a Kirschner wire can be inserted obliquely to bridge the fracture.
10.3.2 Intra-articular Avulsion or Traction Fractures
Make a Y-shaped skin incision over the dorsum of the distal interphalangeal joint ( ▶ Fig. 9.2).
Expose the dorsal intra-articular fracture of the base of the distal phalanx and clean the fracture gap.
Expose the shaft of the distal phalanx bilaterally, if possible as far laterally as the midlateral line. Drill transversely through the distal phalanx shaft ( ▶ Fig. 10.3a).
Exchange the drill for a needle with a sufficiently large lumen.
Insert a tension band wire through the needle and withdraw the needle. The wire remains in the shaft of the distal phalanx with the ends projecting on both sides ( ▶ Fig. 10.3b).
The fracture is reduced and fixed by parallel Kirschner wires in the opposite palmar cortex.
Wire loops are placed proximally around the two Kirschner wires ( ▶ Fig. 10.3c); alternatively, a needle can be advanced transversely palmar to the extensor tendon insertion directly at the base of the dorsal rim/avulsion fragment of the distal phalanx ( ▶ Fig. 10.3d).
After placing the distal tension band wire ends in a figure of 8, they are twisted evenly with the proximal tension band wire on either side to compress the fracture ( ▶ Fig. 10.3e).
The projecting Kirschner wires are bent and shortened so that they can be buried subcutaneously. The skin is sutured.
Note
The tension band wires must be tightened symmetrically with care so as to avoid fracturing the avulsion fragment.
Fig. 10.3 Tension band wiring of an avulsion fracture. (a) After a Y-shaped incision over the dorsum of the distal interphalangeal joint, the fracture is exposed and cleaned. The shaft of the distal phalanx is exposed bilaterally as far as the palmar/dorsal midline. The distal phalanx shaft is drilled transversely. (b) The drill is exchanged for a needle with an internal diameter greater than the outer diameter of the tension band wire. The wire is pulled through the needle and removed by drawing it over the wire. The wire must project sufficiently on both sides. (c) The fracture is reduced and fixed by two parallel Kirschner wires, which are fixed in the opposite cortex. A second tension band wire is placed proximally around the Kirschner wires over the extensor tendon. (d) Alternatively, a needle can be pushed transversely close to the dorsal bony edge of the base of the distal phalanx. The needle is passed palmar to the extensor tendon insertion. A second tension band wire is threaded through and the needle is withdrawn, leaving the wire in place. (e) The distal tension band wire is placed in a figure-of-8 so that it crosses on the dorsum of the shaft of the distal phalanx. It is twisted with the proximal wire bilaterally, producing interfragmental compression in the fracture. The two Kirschner wires are bent, shortened, and compressed, and the ends are buried subcutaneously by suturing the skin.
10.4 Lag Screw
Internal fixation with a lag screw is an effective method for obtaining functional stable fixation of oblique and torsional fractures. Moreover, lag screws are used for fixation of avulsion fractures and intra-articular metaphyseal fractures. The joint surface is restored without a step-off through interfragmental compression.
In addition a neutralization plate is usually necessary to absorb external forces acting on the fracture in order to achieve, at least, relative stability (see Chapter ▶ 10.5.1).
Percutaneous lag screw fixation through stab incisions is possible with special instruments, which helps to minimize soft tissue trauma (see Chapter ▶ 10.6). Closed anatomical reduction of the fracture by traction and pressure is a prerequisite, but this cannot always be achieved. Often, this method can only provide reduction fixation (adaptive fixation).
10.4.1 Procedure
A gliding hole with the same size as the screw diameter is drilled in the ipsilateral cortex, extending no further than the fracture gap ( ▶ Fig. 10.4a).
Insert a drill guide ( ▶ Fig. 10.4b).
Always drill the threaded hole through a guide: otherwise, axial deviations may occur in the threaded hole and these can lead to fracture of the cortex when the lag screw is tightened ( ▶ Fig. 10.4c).
Drill a threaded hole in the contralateral cortex through the drill guide, with the diameter of the screw core ( ▶ Fig. 10.4d).
Measure the screw lengths using a gage ( ▶ Fig. 10.4e).
When measuring the screw length, measure the shorter length by rotating the hook on the gage. If the self-tapping screw is too long, soft tissue injury may occur, involving the flexor tendons, for example ( ▶ Fig. 10.4f).
Introduce a self-tapping screw of the correct length and diameter ( ▶ Fig. 10.4g).
Practical Tips
If a Kirschner wire was inserted for temporary fracture fixation, this must be removed before the screw is finally tightened to produce interfragmental compression so that locking is avoided.
If there is a risk for the screw head to sink in (e.g., because of poor cortical quality or in the metaphyseal region), use a washer ( ▶ Fig. 10.5a).
When using small-diameter screws, drill only the ipsilateral cortex to obtain adequate purchase over a longer part of the small thread ( ▶ Fig. 10.5b).
Whenever possible, drill and insert the screw from the smaller fragment to the bigger one ( ▶ Fig. 10.5c).
The optimal angle for the lag screw is one half of the angle between the cortex and fracture line ( ▶ Fig. 10.5d).
On transverse section through the bone, the lag screws should be as far as possible perpendicular to the fracture plane ( ▶ Fig. 10.5e).
Several screws of smaller diameter achieve better compression and greater stability than one screw with a larger diameter ( ▶ Fig. 10.5f).
If the lag screw is located in the area covered by the plate because of the course of the fracture, pass the lag screw through the plate ( ▶ Fig. 10.5g).
Ensure that the hole is drilled at a sufficient distance from the apex of the fracture. Otherwise there is a risk of longitudinal fracture of the tip of the fragment when a gliding hole is drilled and when compression is produced by the lag screw ( ▶ Fig. 10.5h).
Fig. 10.4 Lag screw fixation. (a) A gliding hole with the diameter of the screw is drilled in the near cortex. Distance “a” should be as long as possible; see ▶ Fig. 10.5h; for the drilling direction, see ▶ Fig. 10.5d. (b) A drill guide is introduced into the gliding hole.
(c) The threaded hole should always be drilled only through the drill guide in the gliding hole. If drilling is not guided (1), axial deviation can occur in the threaded hole (2), which may result in fracture of the cortex when the lag screw is tightened. See also ▶ Fig. 10.5h. (d) Drill a threaded hole with the diameter of the screw core through the far cortex. See ▶ Fig. 10.5h. (e) Measure the screw length with a gage. (f) Measure the shorter screw length by rotating the hook of the gage; otherwise, the inserted screw will project beyond the far cortex with a risk of soft tissue damage, e.g., flexor tendon injury. (g) Introduce a self-tapping lag screw. See ▶ Fig. 10.5h.
Fig. 10.5 Tips for lag screw fixation. (a) If the cortex is damaged and fragile, e.g., because of osteoporosis, and in the metaphyseal region, use a washer to prevent collapse of the lag screw. (b) When using a thin screw diameter, drill only the near cortex so as to achieve better traction of the lag screw.
(c) When drilling a small fracture fragment, always drill from the smaller to the larger fragment. Otherwise there is a risk that drilling will cause dislocation. (d) The ideal direction for drilling is one-half of the angle between a perpendicular to the fracture plane and a perpendicular to the plane of the cortex. € Whenever possible, drill perpendicularly to the fracture plane and avoid acute angles, especially to the fracture plane. (f) Interfragmental compression is safer and provides greater stability if two lag screws of smaller diameter are used rather than one lag screw of greater diameter. (g) Depending on the course of the fracture, a lag screw can also pass through a plate. The other screws in the plate can be fixed-angle locking and standard cortical types. (h) When the ends of the fracture are tapered, there is a risk of longitudinal fracture due to drilling of a gliding hole or compression of the lag screw.
10.5 Lag Screw plus Neutralization Plate
10.5.1 Procedure
Insert a lag screw to produce interfragmental compression ( ▶ Fig. 10.6a; see Chapter ▶ 10.4.1).
Match the shape of the plate (size and design) to the anatomy and place it in position.
Place a standard cortical screw in the proximal plate hole, especially when using T- and L-plates (drill, measure, insert the screw). Before fully tightening the screw, align the axis of the plate correctly with the shaft of the bone ( ▶ Fig. 10.6b).
Only then, place the second screw in the short limb of the plate ( ▶ Fig. 10.6c).
Place screws in the remaining plate holes; fixed-angle locking screws may be used for better stability ( ▶ Fig. 10.6d).
Drilling for screws in the head of H-, L-, and T-plates should diverge from proximal to distal to avoid the screws colliding intraosseously ( ▶ Fig. 10.6e).
Practical Tip
Press the plate onto the bone by means of a standard cortical screw and then insert fixed-angle locking screws in the other holes.
Practical tip
If the plate is fixed exclusively with fixed-angle locking screws, it must be contoured and placed exactly anatomically as otherwise there is a risk of too great a gap between plate and bone.
Fig. 10.6 Lag screw plus neutralization plate. (a) The fracture is first fixed with a lag screw to generate interfragmental compression in the gap (see Chapter ▶ 10.4.1 and note Fig. 10.5h). As sufficient stability from this measure cannot be expected, a plate is applied in addition, which neutralizes the forces acting from without (neutralization plate). (b) When an L-shaped plate is used for neutralization, it is first shaped anatomically. A standard cortical screw is placed in the hole in the long axis. The plate is aligned correctly with the shaft before it is finally tightened. (c) After fixing the plate to the bone in the correct axis, a screw is placed in the second hole of the short limb. This ensures the longitudinal alignment of the plate. (d) Fixed-angle locking screws can be placed in the remaining holes to provide what is known as a hybrid plate. (e) When H-, L-, or T-plates are used, it must be ensured that the positions of the screws diverge to avoid screw collisions.
10.6 Percutaneous Lag Screw
Percutaneous lag screw fixation has become established in line with minimization of operation trauma and technical developments. It can be used for
juxta-articular fractures and
spiral and oblique phalangeal fractures.
Prerequisites and advantages A special instrument—the lag screw target bow / reduction forceps—for lag screws, is required. The fracture is reduced and fixed with this multifunctional instrument under image intensification, percutaneously or subcutaneously (using a different target bow). At the same time, this special reduction instrument acts as a drill guide and gage for measuring lag screw length ( ▶ Fig. 10.7).
Fig. 10.7 Lag screw target bow/reduction forceps devices are all based on the same principle, with drill guides and screw guide sleeves that can be exchanged. The lag screw target bow/reduction forceps can be placed beyond the fracture, both percutaneously or after exposure of the bone. (a) Drill guide for screw core diameter (fixation hole). (b) Drill guide for screw diameter (gliding hole). (c) Screw guide sleeve. (d) Percutaneous application of the target bow on the other side of the fracture.
The advantage is the minimally invasive approach, which leads to less soft tissue damage. This method is a sophisticated technique that requires experience. It must be possible to reduce the fracture exactly; both reduction and fixation are possible only under image intensifier control.
If adequate compression of the fracture is achieved with the multifunctional instrument, it may be possible to replace the typical lag screw by a fixation screw or screws, thereby reducing the risk of a longitudinal fracture (see also ▶ Fig. 10.5h).
10.6.1 Procedure
The incision is followed by minimal soft tissue dissection at the level of the fracture.
The appropriate target bow / reduction forceps for the lag screw to be used (percutaneous or subcutaneous) is placed on either side of the fracture.
The toothed end of the lag screw target bow is placed directly on the bone through the minimally invasive tissue opening according to the line of the fracture.
Interfragmental compression and fixation of the fracture are obtained by closing the multifunctional instrument ( ▶ Fig. 10.8a).
X-rays are taken in two planes and rotation is checked by flexing the fingers.
The appropriate drill guide is introduced, initially with the diameter of the screw core.
Drill through both cortices ( ▶ Fig. 10.8a).
Exchange the drill and its guide for drilling the gliding hole (lag screw diameter).
Drill a gliding hole in the near cortex through the appropriate new drill guide ( ▶ Fig. 10.8b) and measure the length.
Insert the screw guide sleeve.
Screw in the self-tapping lag screw ( ▶ Fig. 10.8c).
Repeat this procedure if a second lag screw is placed (long oblique fracture / spiral fracture) ( ▶ Fig. 10.8d).
Remove the lag screw target bow and suture the skin.
An alternative technique, after closing the multifunctional instrument and taking a check X-ray, is to introduce a guide wire and place a self-tapping headless bone screw / cannulated fixation screw of appropriate length.
Fig. 10.8 Percutaneous lag screw fixation. (a) Following incision, the soft tissues are dissected bluntly, the bone is exposed minimally, and the lag screw target bow/reduction forceps device is applied. The fracture is reduced under X-ray control and the fracture is compressed by closing the multifunctional instrument. A fixation hole is first drilled through both cortices with the drill guide for the screw core diameter. (b) The drill guide is exchanged for the gliding hole (screw diameter) and the gliding hole is drilled as far as the fracture gap. (c) The screw length is determined by a gage and a self-tapping standard cortical screw is inserted using the screw guide sleeve. (d) In long oblique or spiral fractures, two lag screws can also be inserted.
10.7 Plate Fixation
Various materials and principles are possible when plates are used for internal fixation. At least stable fixation of the fracture is usually achieved. Commonly used plates include:
Standard/classic plates
Condylar plates
Dynamic compression plates
Fixed-angle locking plates—internal fixator
Hybrid plates
Holes Plates with holes suitable exclusively for standard cortical screws are supplied by the industry:
Rotation hole
Compression hole
Oval compression hole
In addition, there are plates with holes that accept both standard cortical screws and locking screws:
Locking hole
Combination hole
Round hole
Standard/classic plates The stability of a fracture that is managed by fixation with a standard plate and standard cortical screws is produced by the friction between the underside of the plate and the surface of the bone. This requires that the screws be placed firmly in the bone, which is usually ensured by screwing them through both cortices. The disadvantage is that the compression between plate and bone interferes with periosteal perfusion.
Internal fixation with a condylar plate is based on the same principle. Their use is limited to the metaphyses of the fingers.
Locking plates See Chapter ▶ 10.8.
Hybrid plates Plates with locking holes or combination holes can be fixed both with standard cortical screws and with fixed-angle locking screws. When these plates are combined with the two types of screws, they are called hybrid plates (hybrid screw construct).
This type of fixation is preferred for metaphyseal and epiphyseal fractures. The standard cortical screw generally acts as an interfragmental compression or lag screw to restore a smooth joint surface in the case of intra-articular fractures. Fixed-angle locking screws are placed in the shaft to provide axial and rotational stability.
10.7.1 Interfragmental Compression
The stability of plate fixation can be increased by interfragmental compression. However, interfragmental compression with a plate can only be achieved in a few extra-articular fractures of the shaft:
Transverse fractures
Short oblique fractures
Interfragmental compression by means of a lag screw (or screws) is possible in:
Avulsion fractures
Long oblique fractures
Certain intra-articular mono- and bicondylar fractures
There are different methods of achieving interfragmental compression in the region of a fracture (or osteotomy) with a plate:
Dynamic axial compression by eccentric drilling (spherical gliding principle)
By tension device
By central bending of the plate
Interfragmental Compression According to the Spherical Gliding Principle
By drilling eccentrically in an oval plate hole away from the fracture (or less often in a round hole), a thrust on the plate is created when the standard cortical screw is tightened, due to the round shape of the underside of the screw head. The bone fragment is pressed against the opposite side in the region of the fracture. The interplay of the screw hole shape and the eccentric placement of the screw in the hole of the plate creates axial compression.
Select a plate of size and design appropriate to the anatomy and fracture type.
Place a plate with oval holes (combination holes), shaped to match the anatomy as precisely as possible, on the bone, usually on the tension band side.
Carefully reduce the fracture, ensuring correct rotation and axes in both planes.
Fix the plate close to the fracture with a standard cortical screw and neutral, noneccentric drilling: drill, measure screw length, and insert the screw ( ▶ Fig. 10.9a), firstly, if possible, in the fragment nearer to the joint
Then drill eccentrically away from the fracture in the hole next to the fracture in the further-away fragment opposite the already fixed fragment: measure the screw length and insert a standard cortical screw ( ▶ Fig. 10.9b).
When the screw is tightened, the fragment will be pushed toward the fracture site. This generates axial compression on the fracture ( ▶ Fig. 10.9c, ▶ Fig. 10.9d, ▶ Fig. 10.9e).
Compression can be increased by placing a second supplementary screw eccentrically in the adjacent hole ( ▶ Fig. 10.9f).
Practical Tip
Before finally tightening the third screw, the second screw must be loosened a little ▶ Fig. 10.9f. The stability of the screw core must not be strained when it is tightened (because of the risk of the screw head breaking).
Then place cortical screws or fixed-angle locking screws in the other holes of the plate, as necessary.
In the case of oblique fractures, interfragmental compression can be further increased by a lag screw introduced through the plate ( ▶ Fig. 10.9g).
Practical Tips
To avoid axial deviation and rotation errors when T- and L-plates are used, the following should be noted:
The plate must be curved exactly to fit the anatomy of the bone.
Drill the first hole in the smaller fragment in the long axis of the bone shaft ( ▶ Fig. 10.10a).
Fix the plate with the first screw in the smaller fragment ( ▶ Fig. 10.10a).
Reduce the longer fragment in the correct axis and check the rotation. Fix it temporarily with a plate reduction forceps ( ▶ Fig. 10.10a).
If necessary, correct the reduction by bending, rotating, or twisting the plate.
Place the second screw in the smaller fragment ( ▶ Fig. 10.10b).
Again check the axis and rotation and correct if necessary by bending, rotating, or twisting the plate.
Drill in the larger fragment eccentrically, as described above ( ▶ Fig. 10.10c).
Tighten the screw to obtain interfragmental compression ( ▶ Fig. 10.10d).
Only when the plate is placed correctly and the fracture is in anatomical position, place cortical screws or fixed-angle locking screws in the rest of the holes in the larger fragment.
Fig. 10.9 Interfragmental compression using the spherical gliding principle. (a) To obtain compression of the fracture by means of the spherical gliding principle, the plate must first be secured through a hole close to the fracture by neutral drilling and standard cortical screw fixation. (b) Drill non-neutrally and asymmetrically in the plate hole away from the fracture, i.e., in the oval compression hole, at the side of the hole further away from the fracture. (c) When the standard cortical screw is tightened, the rounded underside of the screw head collides with the “lopsided” underside of the plate hole. (d) When it is tightened further, the plate moves on the bone surface and the screw head slips into the neutral position of the plate hole. (e) This interplay produces compression of the fracture. (f) Increased fracture compression can be achieved by double use of the spherical gliding principle but the already-placed second screw must be loosened somewhat before the third screw, placed the other side of the fracture, is finally tightened. (g) With oblique fractures, the interfragmental compression can be increased or stabilized by an additional lag screw.
Fig. 10.10 Avoidance of axial deviation and rotation errors during interfragmental compression according to the spherical gliding principle.
(a) For fractures in the metaphyseal region, the L- or T-plates must first be fixed in the smaller fragment next to the joint with a neutrally drilled screw in the long axis of the bigger shaft fragment. After aligning the plate in the correct axis, rotation is checked and the bigger fragment is fixed temporarily with the plate using a reduction forceps.
(b) The second plate hole in the smaller fragment next to the joint is also fixed neutrally with a diverging screw.
(c) As described above ( ▶ Fig. 10.9b), an asymmetric hole is drilled away from the fracture (view from above).
(d) Fracture compression is produced by tightening the screw (see ▶ Fig. 10.9e) (lateral view).
Interfragmental Compression by Tension Device
Select a plate of size and design appropriate to the fracture type.
Contour and adjust it to the anatomy.
Reduce the fracture exactly, ensuring correct rotation and axes in both planes.
Fix the plate close to the fracture, if possible on the tension band side and, if possible, in the smaller fragment, usually close to the joint.
Note
When fixed-angle locking screws or a fixed-angle locking plate is used, the plate must be contoured precisely to the anatomy.
Check before placing the second screw:
Is the plate lying exactly on the bone?
Is there any rotational error?
Place the second screw in the smaller fragment, usually the one closer to the joint; in this way, the plate is stabilized in the fragment with the rotation and axis correct ( ▶ Fig. 10.11a); usually it is not necessary to use fixed-angle locking screws in the smaller metaphyseal fragment.
The anatomically reduced fracture is fixed temporarily using a plate reduction forceps:
A hole is drilled through the cortex outside and in extension of the plate, large enough for one pointed jaw of a reduction forceps to be seated securely; the hole must be drilled at a slight angle from dorsal further from the plate to palmar closer to the plate.
The second jaw of the reduction forceps is inserted in one of the holes of the plate already fixed ( ▶ Fig. 10.11b).
Interfragmental compression is produced by closing the reduction forceps ( ▶ Fig. 10.11c).
After checking the axis and rotation, screws are inserted in the free holes, using standard cortical screws or fixed-angle locking screws
Note
Insert the screws in diverging direction to avoid intraosseous screw collision ( ▶ Fig. 10.11d)!
Fig. 10.11 Interfragmental compression with an tension device. (a) The plate is fixed neutrally, usually in the smaller fragment first. When L-, T- or H-plates are used, the fracture is reduced anatomically and rotation checked. A neutral screw is placed in the smaller fragment in the second plate hole. If fixed-angle locking screws are used, the plate must fit the bone very precisely. (b) A hole is drilled outside the plate in the long axis of the plate obliquely angled toward the plate. The diameter must admit one pointed jaw of a reduction forceps. The other jaw of the reduction forceps is inserted in a plate hole of the already-fixed plate. (c) The fragment is compressed by closing the forceps. (d) After checking the axis and rotation, screws are inserted in the remaining plate holes to maintain interfragmental compression, ensuring that the screws are in diverging positions.
Interfragmental Compression by Bending the Center of the Plate
This procedure should be regarded only as a reserve measure, as it has not been proven effective when plates are used in the hand. It can be employed only with standard cortical screws.
The plate is bent beforehand so that the ends sit on the bone and there is a gap between the plate and the bone at the level of the fracture.
The plate is first fixed at the two outer holes ( ▶ Fig. 10.12a).
The other holes are then filled from outward to the center, alternating the two sides ( ▶ Fig. 10.12b).
Compression in the fracture region is produced by pushing the fragments toward each other, “pulling” the bone toward the plate ( ▶ Fig. 10.12c).
Fig. 10.12 Interfragmental compression by prior bending of the center of the plate. This method has not become accepted in the hand. It should only be used as an alternative in an emergency. It can be done only with standard cortical screws. (a) The ends of a plate bent in the center are fixed. (b) The free holes are then filled, moving from the outer ends to the center, alternating the two sides. (c) Final appearance with compression of the fracture.
10.8 Fixed-Angle Locking Plate—Internal Fixator
10.8.1 Principles
The unidirectional locking screw requires that drilling through the plate hole and bone is in a precisely defined direction. The locking screws can be inserted in a multiaxial drill-guide funnel of ± 10° or 20° depending on the manufacturer (see Chapter ▶ 8.2).
As regards stability, internal fixation of a fracture with a plate and locking screws represents an internal fixator. The plate and screws form a stable, rigid unit that is independent of friction between the plate and bone surface and depends mainly on the rigidity of the construction.
Fixation of a fracture with controlled minimal movement in the fracture region is important for fracture healing. Complete rigid fixation without interfragmental compression must be avoided as it leads more often to delayed bone union or even pseudarthrosis. The axis, rotation, and length of the bone should be restored by reduction; in the case of intra-articular fractures, a completely stable joint surface without step-off must be achieved first by interfragmental compression using lag screws.
Bridging fixed-angle locking plates can be used for osteoporotic bone and extensive areas of comminution. In these situations the fixed-angle locking operation technique represents major progress ( ▶ Fig. 10.13).
Fig. 10.13 Management of a shaft fracture with an extensive comminution zone using fixed-angle locking fixation by means of a bridging plate, e.g., using a staggered Z-plate. (a) View from above. (b) Lateral view.
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