- See:
-
forces acting on hip joint
-
proximal femoral shaft fractures:
- Discussion:
-
definition:
- between lesser trochanter and 5 cm distal, even as far as center of isthmus of the femoral shaft;
- technically starts below the lesser tuberosity;
- medial and posteromedial cortex is a site of high compressive forces, while the lateral cortex experiences high tensile stresses;
-
anatomy and factors in healing:
-
mechanism and displacing forces:
- high trauma (young pts)
- minor fall (older pts)
- pathologic frx second to metastatic disease (older pts);
- usually direct trauma; fall in elderly, or trauma in young;
- may appear independently of or w/ intertrochanteric frx;
- subtroch frxs are displaced by muscle forces attached to ea frx frag;
- thigh muscles produce shortening and varus;
-
psoas attachment pulls lesser troch proximally & anteriorly;
-
classifaction and frx stability:
- internal fixation for proximal femur frx counteracts deforming forces;
- successful treatment restores medial cortex by secondary bone healing w/ callus, by exact reduction of frx fragments followed by secure
healing, or by medial bone grafting w/ subsequent consolidation;
- when the medial cortex is reconstituted, a lateral plate acts as tension band and is subjected to a bending load;
- Treatment Options:
-
sliding screw fixation in subtroch frx:
-
AO 95 deg condylar screw / blade plate:
-
intramedullary nailing for subtrochanteric frx:
- positioning:
- if the reduction looks challenging, then consider the lateral position over the fracture table;
- the lateral position allows free motion of the thigh and knee joint which is often required for anatomic reduction, and
the lateral position facilitates posterior exposure of the femur (which is often necessary);
- reduction:
- ask the anesthesiologist for absolute muscle relaxation (paralysis), and remember that much higher doses of paralytic are
required to relax the larger muscles (gluteus maximus) as compared to the hand intrinsics (which are often used to
determine if paralysis is present);
- determine if fracture fragments are amenable to lag screw fixation prior to plate application;
- this may convert a complex mult-part frx to a more simple 2 or 3 part frx;
- if
lesser troch is still attached to proximal fragment,
psoas becomes deforming force causing flexion and external rotation of proximal fragment;
- 90 to 90 position aligns distal fragment;
- abduction of distal fragment may be needed to compensate for hip abductor force on the proximal frag;
- indications for bone grafting:
- see:
bone graft harvest technique:
- frx w/o anatomic reduction & w/ medial gap;
- frxs treated by closed
IM Nailing w/ locked nail are not bone grafted thru an open incision;
- bone grafting is performed by packing reamings of femoral canal thru chest tube inserted over guide wire down to the level of fracture is done in all such cases;
- Postoperative Care:
- initiation of wt bearing to soon postoperatively to be one of major causes of fracture healing complications;
- frxs w/ medial or segmental comminution must be protected, regardless of device used, for at least 6-8 weeks until early
healing is radiographically evident;
- only touch down wt bearing is allowed for 6-8 weeks when compression hip screw is used; (w/ sig comminution upto 12 wks
of non wt bearing may be required);
- full wt bearing is allowed when there is x-ray evidence of healing;
- when the Zickel Nail or IM Nail is used, partial wt bearing on crutches is allowed when muscular control of the limb is present;
- progression to full wt bearing is allowed w/in limits of pain;
References for Subtrochanteric Frx:
Treatment of unstable intertrochanteric and subtrochanteric fractures in elderly patients. Primary bipolar arthroplasty compared with internal fixation.
Early versus delayed stabilization of femoral fractures. A prospective randomized study.
Postoperative improvement of walking capacity in patients with trochanteric hip fracture: a prospective analysis 3 and 6 months after surgery.
Unstable intertrochanteric/subtrochanteric fractures of the femur.
Trochanteric fractures. Mobility, complications, and mortality in 607 cases treated with the sliding-screw technique.
Complications of Ender-pin fixation in basicervical, intertrochanteric, and subtrochanteric fractures of the hip.
Low-energy subtrochanteric fractures in elderly patients: results of fixation with the sliding screw plate.
Biologic plating versus intramedullary nailing for comminuted subtrochanteric fractures in young adults: a prospective, randomized study of 66 cases.
