Статьи

Пластина тибиальная дистальная с угловой стабильностью

 

5.733.05.jpgThe management of distal fractures of the tibia, particularly those involving the joint surfaces, is demanding. The
implant presented here combines the advantages of a fixator with the principle of an angle-stable plate that
allows internal fixation. The distal tibial plate is available in different lengths and is anatomically preshaped. It is
fixed to the tibia medially.

 The implant is designed in small-fragment dimensions. The distal tab enables fixation of the medial malleolus5.732.05.jpg
with a conventional small-fragment screw. At the distal end of the plate, there are angle-stable screw holes that allow a variation of up to 20° in the angle of the screws. The given radiation of the screws ensures that the screws can achieve angle-stable fixation of all the main fragments of the epiphysis and metaphysis without touching. There are two more screw holes on the anterior plate flange which are used for fragment fixation in the
antero-posterior direction. The plate cross-section is reinforced proximal to the metaphysis. The undercut diminishes the contact surface on the bone and allows the plate shape to be corrected. The implant reproduces
the average anatomy and the shape can be altered with the usual bending instruments. On the proximal limb of
the plate, the surgeon can choose to occupy the screw holes with conventional or angle-stable small-fragment
screws because of the special design (combihole). When inserted as angle-stable screws, the screws diverge
alternately. This diminishes notching stresses in the bone and thus the risk of secondary implant migration.

Indication

The implant was developed for the operative management of fractures of the intra-articular distal tibia and
also extra-articular fractures of the distal tibia.
If a fracture running in the frontal plane is present, (additional) anterior plate stabilisation by a different implant
is necessary.

General remarks on the management of fractures of the distal tibia

The management of distal tibial fractures, especially intra-articular fractures, is demanding and should be reserved
for experienced surgeons. With complex fractures, a two-stage procedure is indicated with primary treatment of the
fibula, minimally invasive reduction of the joint block and fixator assembly. Internal fixation is performed only when
the soft tissues have stabilised. Preoperative imaging includes conventional radiographs of the ankle joint in
3 planes, of the lower leg and knee in 2 planes and a thin-layer CT if the intra-articular distal tibial shaft is involved.
The perfusion of the soft tissues, particularly if there is a concomitant fibular fracture with the need for a second
incision, and existing soft tissue damage by the trauma make high demands in the choice of approach. Immediately
medial incisions should be avoided and the relevant literature should be referred to. Implant coverage must be ensured.
An alternative is coverage with a free flap within 48 hours after internal fixation. The patient is in supine position and
is given perioperative antibiotic prophylaxis; use of a thigh tourniquet is optional.

Advantages

  1. The preshaped anatomical plate design increases the safety of use and reduces the operation time
  2. Use in articular and extra-articular tibial fractures
  3. Use of the small-fragment size alone reduces stock maintenance costs and facilitates tray preparation
  4. The angle-stable course of the screws in the metaphyseal tibial joint block includes all the main fragments of the epiphysis and metaphysis
  5. The anterior angle flange ensures high stability of the fixed posterior bone fragments
  6. Variable angle-stable screw fixation in the metaphyseal part of the plate. Conventional or angle-stable screws placed in the diaphyseal part of the plate
  7. Longer plates on request to treat 2-level fractures

OP-Instruction

When there is an intra-articular tibial fracture, the joint block is first restored and retained temporarily with
wires that will not get in the way of the plate. Select a plate of suitable length for the appropriate
side and position it strictly medially with the flange directed anteriorly until it fits optimally with the
bone. If necessary, shape the plate more with bending instruments. The distal tab must always be bent
also and if it is not needed it can be divided with a strong side cutter. The implant can be inserted
minimally invasively. After screwing the drill sleeves into the most distal screw holes, the direction of the
screws and the level of the plate‘s position relative to the joint can be set with a K-wire parallel to the drill
sleeves. After a radiological check, fix the plate temporarily.

The distal diverging screw holes are first filled with angle-stable screws by screwing on the drill
sleeves, drilling with a 2.5 mm drill and insertion of small-fragment head-locking screws. Use the
given screw directions as standard, particularly in the case of intra-articular fractures, in order to
avoid collisions of the screws. The screws can be inserted in angle-stable mode with up to 20° deviation
from the standard direction. This is usually necessary only with very small or large bones in order to
ensure that the screw runs optimally from medial to lateral close to the cortex. Ensure that there are no
collisions between the screws and consider using smaller cortical locking screws. The medial
malleolus fragment is fixed with a conventional small-fragment screw. Check the outcome of the
internal fixation critically by fluoroscopy. Irritation of the fibula and syndesmosis by screws inserted from
the medial aspect must be avoided and pay special attention to screw length.

After reduction of the restored joint block to the tibial shaft, the proximal plate holes are now filled with
either angle-stable (as described above) or conventional small-fragment cortical screws. Use at least
7 cortical screws and 9 in the case of fractures extending far into the tibial shaft.

After final radiological check and documentation, the wound is closed with a drain and a
wellpadded lower leg splint until the wound has healed.
Postoperative treatment is in accordance with the familiar guidelines. It is limited by the stability of
the internal fixation and patient compliance.