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Split Compression Frx (Type II Frx)


- Discussion: Split Compression /  Type II Fractures:
    - split fragment from articular surface along w/ depressed area similar to that of local compression frx;
    - lateral wedge frx is combined w/ varying deg of depression of adjacent remaining wt bearing portion of lateral tibial plateau;
    - depression is usually located anteriorly or centrally;
    - wedge frx may vary from a small rim fracture to a frx involving upto 1/3 of the articular surface;
    - displacement of frx consists of widening of joint w/ spreading apart of wedge, in combination w/ central depression of lateral plateau;
    - mechanism: valgus stress and axial compression forces that 1st cause frx of split fragment & then cause  depression frx of part of remaining surface;
    - associated injuries:
          - look for fracture of fibular head and neck
          - most often S.C.F. involves lateral plateau;
          - ligament injuries are found in 19% of split compression frx;
                  - look for widening of medial cartilage space of knee &
                  - avulsion of bone from medial femoral condyle;


- Radiographs:
    - CT scan accurately defines anatomy;
    - 20% of SCF have a collat ligament injury;
           - look for widening of medial cartilage space;
           - avulsion of bone from medial femoral condyle;
           - gentle valgus stress may produce deformity of 20 to 25 deg;
    - grade depression by measuring vertical distance between lowest point on medial plateau
                 & lowest depressed frag of lateral plateau;
         - depression > 4 mm is sig. & if left untreated results in joint incongruity, valgus deformity,
                 and a sense of instability;
          
         

- Non Operative Rx:
    - indicated for frx w/ < 6 mm of articular depression assumming that split fragment is restored to its anatomic position w/ traction;
          - split fragments assoc. w/ articular depression of > 6 mm can almost always be reduced, however, articular incongruity will remain &
                    there will be insufficient support for femoral condyle;
    - Traction:
         - even if traction fails to yeild an accetable reduction, pt will note pain relief & will be able to begin early ROM;

- Indications for Operative Treatment:
    - joint surface is depressed  > 1 cm (4 mm in young patients)
    - valgus is > than 10 deg;
    - closed reduction of split fragment is not maintained;
    - associated posterior wedge requires fixation since this significes significant posterior instability;

- Percutaneous Fixation:
    - type II frx may often not be amenable to percutaneous fixation because an acceptable reduction of the depressed fragment can be difficult to obtain;
    - part of the difficult lies in the fact that the depressed fragment is buried  w/ in the plateau and is obsured by the frx lines of split fragment;
    - hence the patient should be forewarned about the need for open reduction;
    - reduction:
           - if the split fragment is depressed, it can be brought out to length with use of a femoral distraction;
           - once the fracture fragment has been elevated w/ ligamentotaxis, then the medial or lateral displacement can be corrected;
           - reduction is achieved w/ percutaneous applied reduction forceps w/ flourscopic assistance;
           - consider applying the reduction forceps eccentrically, and then torque reduction forceps to achieve reduction;
           - adequate reduction implies less than 1-2 mm step off;
           - depressed fragments: make a small window in the metaphyseal cortex and elevate depressed fragment with a bone tamp;
    - fixation:
          - percutaneous screws:
                 - wedge of type I frx of lateral plateau can usually be fixed w/ only cancellous percutaneous lag screws and washers;
                 - consider 6.5 mm cancellous screws (over washers) which are placed in a triangular position;
          - anti-glide screw:
                 - antiglide screws are typically placed after 1-2 percutaneous lag screws are placed thru the frx fragment;
                 - antigluide screws (over washers) are placed just distal to the frx edge to prevent distal displacement;
                         - 4.5 mm cortical screws over washers are typically used;
    - references:
          - [Comparison study on effectiveness between arthroscopy assisted percutaneous internal fixation and open reduction and internal fixation for Schatzker types II and III tibial plateau fractures].
          - Balloon Tibioplasty: A Useful Tool for Reduction of Tibial Plateau Depression Fractures
          - Percutaneous Screw Fixation of Tibial Plateau Fractures.
          - Closed reduction and percutaneous screw fixation for tibial plateau fractures
          - Indirect reduction and percutaneous screw fixation of displaced tibial plateau fractures.

- Open Surgical Treatment: (Synthes Products)
  - PreOp Planning
         - most important step in reconstruction of any intra articular frx, is to expose the fracture w/o devasclarizing the fragments;
  - Treatment Plan:
         - open reduction;
         - elevation of the depressed plateau;
         - bone grafting of metaphysis;
         - fixation of the fracture with cancellous screws
         - butress plating of the lateral cortex;
  - Position:
         - for optimal exposure, consider supine position, w/ a bolster under thigh, & table broken so that the knee is flexed 90 deg;
         - this position allows increased exposure submeniscally;
  - Surgical Approach:
         - consider a longitudinal lateral parapatellar approach;
         - elevate anterior compartment muscles off proximal tibia, exposing tibial flare and split frx;
         - trace frx is to joint line and enter joint thru transverse sub-meniscal interval;
              - if needed, transect attachment of anterior horn of meniscus;
              - elevate meniscus superiorly to expose intra-articular frx segment;
  - Exposure of Depressed Segment:
         - split frx is hinged open anteriorly to expose depressed joint surface;
              - this surface is elevated to appropriate level & defect is filled w/ or local cancellous bone or allografts;
         - apply small impactor from below to disimpact and elevate depressed segment;
         - apply bone graft from below;
         - elevated segment may be supported w/ K wires (consider biodegradable);
         - ref: Inside out rafting K-wire technique for tibial plateau fractures 
  - Reduction:
         - consider use of tenaculum or pelvic reduction clamp across both plateau to generate compression;
  - Implants: (Synthes Products)
         - at this point, the frx has essentially been turned into a type I frx;
         - w/ minimal comminuation and good bone stock, consider 6.5 mm cancellous screws w/ or w/o washers;
         - if cannulated screws are used, these are inserted over K wires;
         - if split fragment is not comminuted, 2 or 3 cancellous screws are  inserted parallel to & > 1 cm distal to articular surface;
               - an additional, cortical anti-glide scrw w/ washer is inserted distally;
         - in older patients, w/ osteoporotic bone, lag screws alone cannot prevent redisplacement of fragments; (need butress plate);
         - a comminuted frx, requires an L or T shaped buttress plate; another indication, for butress plating is assoc subcondylar frx;

               

- Post Operative Care and Compications:
    - Loss of Reduction of split frag is main complication of Rx in split compression frx;
           - this is found more commonly with closed treatment;
    - w/ percutaneous IF, a cast brace is used until frx healing is complete;
    - w/ use of a butress plate to assure rigid fixation, external support  is not required postoperatively


Indirect Reduction and Percutaneous Screw Fixation of Displaced Tibial Plateau Fractures.

Split depression tibial plateau fractures: a biomechanical study.

Combined Arthroscopic Treatment of Tibial Plateau and Intercondylar Eminence Avulsion Fractures

Outcomes of Schatzker II Tibial Plateau Fracture Open Reduction Internal Fixation Using Structural Bone Grafts