Introduction
Hip fractures can be divided into two groups: intra-capsular femoral neck fractures (further localized as subcapital, transcervical or basicervical) and extra-capsular peri-trochanteric fractures, namely the intertrochanteric and subtrochanteric fractures.
See Hip fractures for a general discussion.
Unlike a femoral neck fracture, the intertrochanteric region has good blood supply to cancellous bone, and thus has good healing potential. Unlike a subtrochanteric fracture, it can be (but not always is) inherently stable.
Anatomy
As the name implies, an intertrochanteric fracture is one where the fracture line lies between the greater and lesser trochanters. Muscle attachments must be kept in mind. The abductors and short external rotators attach to the greater trochanter; the iliopsoas to the lesser. The adductors attach to the shaft below the intertrochanteric region, possibly displacing the shaft medial relative to the proximal fragment(s).
Classification
Intertrochanteric fractures can be classified (Evans, 1949) as the following Types:
I non displaced with no comminution
II displaced with no comminution;
III displaced with greater trochanteric (posterolateral) comminution;
IV displaced with lesser trochanteric (posteromedial); and
V reverse obiliquity
A special category is the "reverse obliquity fracture". In reverse obliquity fractures, the fracture line courses laterally as it extends from proximal to distal, running perpendicular to the intertrochanteric line. Even if there is no comminution and even if the fracture line does not reach the subtrochanteric region, this fracture is unstable and prone to displacement with conventional sliding screws, as the fracture line is parallel to the course of the sliding screw and displaces as the screw slides.
The key criterion of any robust classification is whether the fracture can be considered stable or unstable.
Presentation
Intertrochanteric fractures are often seen in frail older people after low energy falls (ie, from a standing height). Although the kinetic energy of such a fall is far more than is needed to break the bone, most falls do not lead to fracture. This gives rise to the conjecture that poor soft tissue padding, poor reflexes and weakness are actually what causes the fracture. This is not so much an academic debate about causality but a warning to clinicians to expect -and seek, if not initially found?medical co-morbidities. Patients with hip fractures are typically sick, but they were sick in the moments preceding the fracture as well, in all likelihood.
Diagnosis
Care must be taken to rule out the more benign isolated fracture of the greater trochanter; an MRI or CT may be needed for that purpose. An isolated fracture of the greater trochanter may occur as an avulsion by the gluteus medius, and needs only symptomatic (palliative) treatment
Occult fractures are rare but not impossible. A patient with hip pain after a fall whose xrays are (apparently) negative needs admission to the hospital and an MRI.
As noted, medical co- morbidities can be expected. These should be identified and optimized as well as can be done without delaying surgery unnecessarily.
Treatment
In any patient who hopes to get out of bed, the treatment of intertrochanteric fractures is surgical.
The traditional treatment in recent decades is the sliding hip screw. This device has a large screw in the femoral head and neck engage a plate fixed to the shaft, with sliding of the screw allowed if and when the fracture impacts.
Intra-medullary devices (cephalomedulary nails) theoretically offer less soft tissue dissection and a shorter moment arm (the vertical device, ie the nail, is closer to the hip center than the plate would be).
Intra-medullary fixation may be preferable for reverse obliquity fractures of those with sub-trochanteric extension. Other options for these types include varus fixed angle devices such as a blade plate or a 95 degree sliding hip screw; or more recently a locked proximal femoral plate. In reverse obliquity fractures, the fracture line courses laterally as it extends from proximal to distal and typically reaches the subtrochanteric region. Because of that geometry, these fractures are more prone to failure when fixed with traditional sliding screws: the shaft displaces medially and the fracture does not compress as the screw "slides". Fractures with sub-trochanteric extension may demand a very long plate, a bigger operation; whereas using a longer nail is not much bigger a case than using a shorter one.
In using implants with a large single lag screw (traditional sliding hip screw or cephalomedulary nail), it is imperative to (1) obtain a reduction of the major fragments and (2) to keep the Tip Apex Distance (TAD) to less than 25mm (Baumgartner, 19XX). The TAD is the sum of the distance from the tip of the lag screw to the femoral head fovea as measured on AP and Lateral views. A distance of greater than 25mm is strongly associated with an increased risk for screw cut out (Baumgartner, 19XX).
Complications
These patients are sick, and many are "pushed over the edge" so to speak from their fractures. The fracture heralds, but does not truly cause, the patient's demise.
Complications from surgery relate mostly to hardware failure or cut out.
DVT is an issue, especially since it is (equally) dangerous to over-thin the blood as well.
Red Flags and Controversies
? Timing of surgery: 'medical optimization' vs 'harmful delay'
? Admit to medicine or ortho?
? Sliding hip screw vs IM device?
? Can we classify accurately?
? What causes the fracture?osteoporosis or medical diseases leading to falls and poor absorption of energy?
Outcomes
Misc.
