Subtrochanteric Fracture Stability

- Discussion:
    - classifaction and fracture stability
    - frx stability is based on presence or absence of posteromedial butress;
    - farther down shaft of femur primary frx is located, greater incidence of delayed union and implant failure;
    - forces acting on hip joint
           - most compression stresses are located 1-3 inches distal to lesser troch;

- Stable Frx:
    - those frx in which it is possible to reestablish bone to bone contact of the medial and post femoral cortex;
    - when not possible: internal fixation device will act as tension band on lateral femoral cortex, & impaction & wt bearing can occur directly thru the medial cortex;

- Unstable Frx:
    - w/ unstable frx, comminution results in loss of medial cortical continuity, and presents a high rate of healing complications and implant failure;
    - medial cortical opposition is not obtained 2nd to comminution &/or fracture obliquity;
           - in this situation, medial cortical support is inadequate;
           - lateral plates or IM devices are subject to bending stress, and loads concentrate in one area of the implant;
           - this results in implant failure or loss of fixation;
    - in frxs distal to lesser troch, stability can be restored by osteotomy or medial displacement, as
    - above all avoid treating unstable fractures like stable ones; (i.e., avoid the following);

             

- Seinsheimer's IIIA and IV:
     - account for almost all of implant failures and non unions;
     - in both types there is frequent medial cortical comminution that results in lack of stability after internal fixation;
           - farther down femoral shaft frx is located, greater incidence of delayed union and implant failure



Original Text by Clifford R. Wheeless, III, MD.

Last updated by Data Trace Staff on Wednesday, September 19, 2012 11:20 am