- Classification into "Stiff" and "Lax" Pseudoarthrosis:
    - stiff pseudoarthrosis:
         - bone ends are hypertrophic
         - hypertrophic non union should first be compressed for 2-3 weeks, followed by gradual distraction;

- Lax Non Union:
    - lax nonunion of tibia is often equated w/ synovial pseudoarthrosis;
    - type I:
         - pseudoarthrosis with osteopenia at bone ends;
         - after resection of lax pseudoarthrosis iniate compression for 2 weeks, & then follow w/ gradual distraction osteogenesis;
    - type II:
         - pseudoarthrosis w/ bone ends that are sclerotic for 1-2 cm
         - w/ sclerotic bone ends, then osteogenic reparative process, is impaired;
         - sclerotic bone ends will defy attempts of healing w/ compression and distraction osteogenesis;

- Treatment:
    - synovial pseudoarthrosis should not be treated w/ electrical current to stimulate osteogenesis;
    - should be treated w/ resection of pseudoarthrosis, bone grafting,  & rigid internal or exernal fixation;
    - if skin coverage is poor, a local soft tissue flap or vascularized free flap may be necessary to achieve union;
    - if frx is in good alignment w/ stable fibrous union, autogenous cancellous bone grafting packed around frx site in vascular soft tissue bed may obtain union;
    - w/ Ilizarov, pseudoarthrosis may be treated w/ compression for 2 to 3 weeks which creates stability and crushes fibrous and fibrocartilaginous tissues between the bone ends;
          - consider resecting tibial non union & then beginning compression-distraction;
                - compression of non union site is done simultaneously as distraction of the corticotomy site;
          - once bone contact is obtained, compression of the non union is performed;
          - if there is less than 2 cm of shortening after synovial pseudoarthrosis, then begin compression for 2 to 3 weeks, followed by gradual distraction;
          - need for stability:
                - w/ insufficient stability tissues may fail to ossify & will rather go thru a cartilagenous stage;
                - w/ addition of rings and tranfixation wires, stability is enhanced which tends to enhance ossifcation