TIBIAL PILON FRACTURES- An Update
Siddharth Sharma, Hitesh Gopalan U
HISTORY
· ‘Pilon’ is a french word meaning ‘pestle’ and this term was coined by Etienne Destot in 1911 to describe fractures occurring within 5 cm of the ankle joint.
· ‘Plafond’ means ‘ceiling’. This term was coined by Bonnin in 1950, in allusion to the tibio-talar articular cartilage injury that occurs with these injuries.
DEFINITION & RELEVANT ANATOMY
Although the common feature of all tibial pilon fractures is involvement of the distal tibial articular surface, two distinct injury patterns can be identified:
| SNo. | FEATURE | AXIAL LOAD INJURIES | ROTATIONAL INJURIES |
| 1 | Mode of injury | High velocity trauma with axial compression | Low velocity rotational forces |
| 2 | Tibial fracture pattern | Variable comminution and impaction of the distal tibial articular surface and metaphysis | Minimal or no comminution, no impaction and no metaphyseal involvement. |
| 3 | Fibular fracture pattern | Variable | Variable |
| 4 | Displacement of talus | Proximal displacement | Lateral displacement |
| 5 | Soft tissue injury | Severe | Minimal |
| 6 | Prognosis | Less favourable | More favourable |
Rotational injuries involving the tibial pilon can be regarded as being a continuum of ankle fractures and are managed as per the principles that guide ankle fracture fixation.
EPIDEMIOLOGY
1. INCIDENCE
a. Account for less than 10% of all lower extremity fractures.
b. Incidence is increasing owing to the use of seatbelts and airbags, which have decreased the incidence of fatal chest and abdominal injuries in high velocity motor vehicle accidents.
2. AGE: average age is 35 – 40 years.
3. SEX: males are more commonly involved.
CLASSIFICATIONS
1. REUDI – ALLGOWER CLASSIFICATION
| CATEGORY | DISPLACEMENT | COMMINUTION |
| TYPE I | Undisplaced | Cleavage fracture, no comminution |
| TYPE II | Displaced | Minimally comminuted |
| TYPE III | Displaced | Highly comminuted |
2. AO/OTA CLASSIFICATION OF TIBIAL PILON FRACTURES
| TYPE A – EXTRA ARTICULAR FRACTURES |
| A1 | Metaphyseal Simple |
| A2 | Metaphyseal Wedge |
| A3 | Metaphyseal Complex |
| TYPE B – PARTIAL ARTICLUAR FRACTURES |
| B1 | Pure Split |
| B2 | Split Depression |
| B3 | Multifragmentary Depression |
| TYPE C – TOTAL ARTICULAR FRACTURES |
| C1 | Articular Simple, Metaphyseal Simple |
| C2 | Articular Simple, Metaphyseal Multifragmentary |
| C3 | Articular Multifragmentary |
Inter – rater reliability is better with the AO/OTA classification.
3. TSCHERNE & GOETZEN CLASSIFICATION OF SOFT TISSUE INJURY
| GRADE | SKIN INJURY | MUSCLE INJURY |
| GRADE 0 | None | None |
| GRADE 1 | Significant abrasion or contusion | None |
| GRADE 2 | Deep abrasion with local contusion | Mild |
| GRADE 3 (Includes compartment syndrome and arterial injuries) | Extensive contusion or crushing with subcutaneous avulsion | Severe |
CLINICAL FEATURES
1. MODE OF INJURY:
a. Axial compression injuries: are high velocity injuries and occur with motor vehicle accidents. There is rapid loading of the bone and release of large amount of energy at failure, which gets disseminated to the soft tissues.
b. Rotational injuries: occur as a result of torsional forces applied to the ankle. Loading in these cases is slow and less amount of energy is released at failure, therefore there is minimal soft tissue disruption.
2. ASSOCIATED INJURIES
a. Incidence of concomitant injuries: 27 – 51%
b. Incidence of bilateral tibial pilon fractures: 0 – 8%
c. Ipsilateral talus and calcaneal fractures: extremely uncommon with axial loading fracture patterns. This is because most of the energy gets absorbed in the distal tibia and this protects the talus and calcaneum.
3. SOFT TISSUE INJURY
a. Severe soft tissue injury occurs with axial loading fracture patterns.
b. Tense soft tissue swelling is palpable and may also be appreciated by absence of wrinkles; conversely the re-appearance of wrinkles indicates healing of the tissues (wrinkle test).
c. Blisters indicate soft tissue injury and can be categorized as:
i. Clear fluid filled blisters
ii. Blood filled blisters
Although both types are caused by separations at the dermo – epidermal junction, blood filled blisters indicate severe soft tissue injury.
4. NEUROVASCULAR INJURIES
a. CT angiography demonstrated vascular injury in 52% of cases in a recent study.
b. Tibialis anterior artery is the most commonly involved .
DIAGNOSIS
1. RADIOGRAPHS: obtain Antero-posterior, Lateral and Mortise views (AP radiograph with the ankle in 15 degrees internal rotation) in all cases, full leg radiographs to rule out proximal extension, contralateral ankle radiograph as template for preoperative planning.
2. CT SCAN: helps in determining the degree of articular involvement, impaction and comminution and is also a useful adjunct to assess the quality of reduction.
GOALS OF TREATMENT
1. To obtain an anatomical articular reduction.
2. Restoration of axial alignment.
3. Maintenance of joint stability.
4. Achieve fracture union.
5. Regain functional and pain-free weight bearing and motion
6. Avoiding infections and wound complications.
It may be impossible to achieve all these goals in all cases and therefore treatment should be individualised.
EMERGENCY MANAGEMENT
1. Stabilize the patient as per the Advanced Trauma Life Support (ATLS®) protocols as most of these injuries are high velocity motor vehicle accidents.
2. Life threatening head, abdominal, chest or other injuries take precedence in management.
3. Talus should be reduced immediately and the ankle should be immobilized in a bivalved cast or slab and elevated.
4. If the talus cannot be reduced, a calcaneal Steinmann pin can be used to deliver 10 pounds (approx. 4.5 kgs) of traction over a Bohler frame.
5. Alternatively, a joint spanning external fixator can be used to achieve and maintain provisional reduction of the fracture as well as talus.
INDICATIONS OF CONSERVATIVE TREATMENT
The overwhelming majority of Pilon fractures need operative treatment. Indications of conservative management are limited and include:
1. Minimally displaced ‘A’ or ‘C1’ fractures.
2. Moribund and medically unfit patients.
TIMING OF ORIF
Open reduction and internal fixation of Pilon fractures should be delayed for several reasons:
1. It has been shown that the trans-cutaneous oxygen concentration at the fracture site drops after injury and remains low up to 10 days after injury.
2. Incisions that are placed through compromised soft tissue envelopes may end up in wound dehiscence, necrosis and infection.
3. Soft tissue swelling may preclude closure of the surgical wound and tightly applied sutures can worsen the soft tissue compromise.
SURGICAL APPROACHES FOR PILON FRACTURES
| APPROACH | TECHNIQUE | ADVANTAGE | DISADVANTAGE |
| ANTEROMEDIAL & LATERAL(CLASSICAL) | Separate incisions for tibial and fibula | Good visualization of fracture site | Wound breakdown, hardware prominence |
| DIRECT LATERAL | Both tibia & fibula approached through a single incision centred over posterolateral border of fibula | · Excellent exposure with fewer wound complications. · Minimal risk of injury to superficial peroneal nerve | · Difficult to address fractures of the posterior aspect of the tibial pilon · Difficult to address medial comminution |
| ANTEROLATERAL | Both tibia and fibula can be approached by skin incision centred over anterior border of fibula | Excellent exposure with fewer wound complications | · Iatrogenic damage to superficial peroneal nerve and anterior perforating peroneal artery. · Difficult to address medial comminution |
| POSTEROLATERAL | Utilizes the interval between peroneal tendons and flexor hallucis longus | · Provides good exposure for fractures that have posterior displacement & comminution · Also useful when skin condition rules out anterior approaches | · Difficult to address anterior displacement or comminution · Incidence of wound complications is same as with other approaches. |
| MINIMALLY INVASIVE PLATE OSTEOSYNTHESIS (MIPO) | Limited incisions, indirect reduction techniques, bridge plating principle used | Minimizes further damage to the compromised bone & soft tissues | Articular comminution is difficult to address |
The choice of surgical approach is dictated by the soft tissue status, fracture displacement and the location of articular comminution.
INITIAL MANAGEMENT
It is aimed at reduction of gross displacement of the talus and elevation of the limb. This can be accomplished by:
1. Plaster slab or bivalved cast.
2. Calcaneal pin traction and elevation on a Bohler frame.
3. Spanning external fixator.
CHOICE OF OPERATIVE PROCEDURES
1. SINGLE STAGE MANAGEMENT
It is preferred for displaced fractures with minimal, closed, soft tissue injury.
2. MULTIPLE STAGE MANAGEMENT
Majority of Pilon fractures have moderate – severe soft tissue injury, with or without compounding and are best managed by staged treatment protocol, as follows:
· Stage 1: Closed reduction and external fixation: This may be accomplished by any of the following methods:
o Ankle spanning External Fixator:
§ Utilizes pins placed in the tibia and in the calcaneum & /or talus.
§ Advantages: zone of injury is spanned, quick and easy to apply, holds out to talus to length, no further injury to soft tissues and does not preclude other treatments.
§ Disadvantage: ankle joint movements are lost, although this may not have much bearing on the final outcome.
o Non-spanning External Fixator:
§ Pin fixators, Ilizarov fixators and hybrid fixators (employing pins and wire constructs)
§ Advantage: ankle movements are preserved
§ Disadvantage: at least 2 cm of the distal tibia must be intact to allow such a fixation, safe corridors for the distal tibia are limited and higher incidence of pin, wire and wound complications as the fixation passes through the zone of injury.
o Articulated (Hinged) ankle spanning External Fixators:
§ Utilizes a hinge that connects the tibial pins with the hindfoot pins.
§ Advantages: Allows reduction of the displaced talus and also permits limited ankle movements while bridging the zone of injury.
§ Disadvantages: Needs precise pin placement; the hindfoot clamp straddles the neurovascular bundle and the subtalar joint and the calcaneal pin can injure the medial calcaneal branch of the tibial nerve.
· Stage 2 - Definitive Treatment: is begun when soft tissues have healed and there is no evidence of infection in case of open fractures. The different treatment options include:
o Plate Fixation of Tibia:
§ The articular fragments must be reduced under vision anatomically and rigidly fixed with interfragmentary screws.
§ The metaphyseal fractures are dealt with by bridging fixation. Minimal soft tissue dissection, indirect reduction techniques and maintenance of length, alignment and rotation are the goals of treatment.
§ Choice of implants: low profile plates that are contoured to the distal tibia are preferred. The use of precontoured angle stable plates (distal tibial locking compression plates) offers several advantages in complex fractures and osteoporotic bone.
o External Fixation as a definitive modality of treatment:
§ The most important step is to reduce the articular fracture anatomically and if needed, this can be accomplished by limited open reduction and interfragmentary screw fixation.
§ External fixators can be in the form of Ilizarov fixators, tubular external fixators or modular fixators.
o Fibular fixation:
§ Most authors recommend that this should be done at the time of the initial operation.
§ If the fibular fracture pattern is simple, it is fixed first. This permits easy reduction of the tibial fracture. However, in comminuted fibular fracture patterns, the tibia is fixed first.
§ Fixation can be accomplished with one third tubular plates, reconstruction plates or 3.5 mm dynamic compression plates depending on the size of fibula.
Surgical Approaches:
· Although historically a single “utilitarian” approach was popular in the reconstruction of the tibial plafond, a variety of surgical approaches are currently used to treat these fractures.
· Less dissection and soft tissue retraction, as well as optimal implant placement, is possible using more direct approaches.
· As with other complex injuries, the selection of an approach should be based on the personality of fracture and location of major fracture fragments.
· These more customized approaches should adhere to the following principles:
- Effective soft tissue handling
- Maintenance of a reasonable skin bridge between incisions (especially if these incisions are long or extensile)
· Placing skin incisions directly over bone should be avoided if possible. Thus, if skin problems occur, resultant tissue defects can be reconstructed with a simple skin graft or fasciocutaneous flap as opposed to a free soft tissue transfer.
· Howard et al recently reported a series of 46 plafond fractures in 42 patients in which 106 skin incisions were used, creating 60 skin bridges. The mean skin bridge size was 5.9 cm; only 16% were greater than 7 cm.
· All incisions other than two healed uneventfully, and no deep infections or skin bridge compromises were recorded.
COMPLICATIONS
1. WOUND DEHISCENCE & INFECTION
i. Incidence was found to be higher in fractures that are managed by single stage open reduction and internal fixation (67% in one series).
ii. With the use of staged protocol, this complication occurs in < 10% of all cases.
2. DELAYED UNION & NON UNION
i. Incidence is 5% regardless of the modality of treatment used.
ii. High energy comminuted fractures, presence of severe soft tissue injury, aggressive soft tissue dissection and infection predispose to these complications.
3. MALUNION
i. Some amount of malunion is expected to occur after high energy comminuted fracture patterns.
ii. Reported rates in recent series: 4 – 25%
iii. Angular malunion is most common and incidence is higher in cases treated with external fixation and those where fibula was not fixed.
4. ANKLE ARTHROSIS
i. Precise incidence not known, rates up to 50% have been reported.
ii. It is thought that the damage to articular cartilage at the time of trauma is the main determinant of arthrosis, although joint incongruity also plays an important role.
iii. Avascular necrosis of talus and infection are less common causes of arthrosis.
iv. Significant arthrosis develops within 1-2 years of injury and its clinical severity does not correlate with the radiological appearance.
REFERENCES
1) Canale ST, Beaty JH. Fractures of the lower extremity. In Campbell's Operative Orthopedics. 11th ed. Philadelphia: Elsevier; 2007. p. 3193 - 217.
2) Reid JS. Pilon fractures update. Current Orthopaedic Practice2009;20(5):527-33
3) Wade AM, Crist BD, Khazzam M, Della Rocca GJ, Calhoun JH. Pilon fractures. Current Orthopaedic Practice2008;19(3):242-8
4) LeBus GF, Collinge C. Vascular abnormalities as assessed with CT angiography in high-energy tibial plafond fractures. J Orthop Trauma. 2008; 22:16–22.
5) Barei DP. Pilon fractures. In: Buchholz RW, Heckman JD, Court-Brown CM, Tornetta P editors. Rockwood and Green’s Fractures in Adults. 7th ed. Philadelphia: Lippincott Williams & Wilkins; 2010. p. 1928-71.
6) Howard JL, Agel J, Barei D, et al. Challenging the dogma of the 7-cm rule: a prospective study
evaluating incision placement and wound healing for tibial plafond fractures. Orthopaedic Trauma Association annual meeting, Phoenix, AZ, October 5-7, 2006
