Triplane Fracture : Wheeless' Textbook of Orthopaedics

- Discussion:
    - name derives from the fact that the fracture exists in the frontal, lateral, and transverse planes;
    - frx tends to occur in older children and young adolescents during an 18 month window, prior to physeal closure;
          - lateral portion of epiphysis is the last to close leaving it vulnerable to injury;
    - epiphyseal arrest and angular deformity are uncommon;
- there are 3 types of frxs: two-part, three-part frx, and four part;
          - note that this fracture does not fit well into the Salter-Harris classification and is considered an atypical fractures;
    - mechanism:
      - occurs due to external rotation forces;
      - this injury most commonly occurs just before epiphyseal closure & mechanism of injury is forced external rotation.
      - anterior part of frx begins intra-articularly in saggital plane;
- when frx reaches epiphyseal plate, it courses laterally in horizontal plane, and posterior portion changes direction upward in saggital plane;
    - two part frx: (most common)
          - type of SH type IV frx;
          - occurs when the medial portion of of the distal tibial epiphysis is closed;
          - lateral view: shows Salter type IV frx;
          - posterior plafond fragment extends across epiphyseal plate to involve metaphysis of the tibia;
          - may be comminuted w/ separation of posterior half from lateral three fourths;
          - reference:
                    - The medial triplane fracture: report of an unusual injury.

    - three part frx:
           - combination of SH types II & III frx;
           - occurs when only the middle portion of the distal tibial epiphysis is closed;
           - appears as SH type III frx on AP view & type II on lateral;
           - frx of anterolateral portion of epiphysis of distal tibia (similar to Tillaux frx);
           - frx of large posterior fragment comprised of posterior & medial portions of tibial epiphysis plus a large metaphyseal fragment of variable size;
           - medial one fourth of plafond and medial malleolus are left intact;
           - fibula may also be fractured;

- Radiology:
- three part frx appears as SH type III frx on AP view & type II on lateral;
- look for associated spiral frx of fibula (frx occurs in 50% of patients);
- CT scan:
   - there is usually more deformity of articular surface than would be anticipated from radiographs;
         - tomograms may be useful to determine extent of injury & displacement;
           - references:
                 - Pediatric Triplane Ankle Fractures: Impact of Radiographs and Computed Tomography on Fracture Classification and Treatment Planning

- Non Operative Treatment:
- most indicated for extra-articular fractures;
- most two part triplane frx, can be treated by closed reduction under GEA;
- closed reduction is successful when frxs is displaced < 2 mm & when joint surface is congruous;
- closed reduction is achieved by internal rotation of foot & long leg cast for 4 weeks followed by short leg casting for 2-3 weeks;
- these frxs are often assoc w/ significant soft-tissue swelling, which makes maintenance of reduction w/ cast somewhat difficult;
- it is not unusual for reduction obtained to slip once swelling has subsided;

- Indications for Operative Treatment:
- any significant displacement ( > 3 mm) requires surgical fixation;
- most often, 3 part frx will require ORIF;

- Surgical Technique:
- because of complex frx pattern, adequate reduction may be difficult;
- wide dissection may be necessary to achieve reduction;
- surgical technique depends on whether frx is two part or three part frx
- screws used to provide fixation should not cross growth plate, unless patient is nearing the end of growth.
- technique for three part frx:
- open reduction of both SH type II & type III components is necessary & requires adequate exposure;
- implants:
   - stabilization w/ two screws, placed percutaneously, obliquely through anterolateral epiphyseal fragment, & an AP screw to stabilize
posterior metaphyseal fragment;
- incision: anterolateral incision;
- anterolateral fragment is identified and displaced to allow for visualization of posteromedial fragment;
- reduction of posteromedial fragment is achieved under direct vision thru internal rotation and dorsiflexion of foot;
- posteromedial fragment is fixed w/ K wire or cancellous screws in an AP direction from anterior aspect of distal tibia into posterior fragment;
- associated fibular frx is subsequently reduced and fixed;
- at this point, the frx has been essential converted to a Tillaux frx;
- anterolateral fragment is reduced and fixed w/ K wires or cancellous screw;
          - other surgeons advocate fixing the anterolateralfragment first (through an anterolateralapproach), then fixing the posteromedial
                 fragment (w/ reduction achieved using dorsiflexion and internal rotation of thefoot);
          - controversies: ankle arthroscopy to evaluate for articular incongruity;
                 - reference:
                         - Arthroscopically assisted percutaneous fixation of triplane fracture of the distal tibia.