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How to treat subtrochanteric fractures
Our Chief Medical Editor asks 4 Questions of Douglas W. Lundy, MD, FACS, about the diagnosis and treatment of these difficult fractures.
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Subtrochanteric fractures of the femur can challenge even the experienced surgeon and preoperative assessment and understanding are key to optimal results. I have turned to Douglas W. Lundy, MD, FACS, to help clarify definition considerations and special surgical challenges related to these special fractures of the femur. I am pleased to share his succinct responses to my questions.
Douglas W. Jackson, MD
Chief Medical Editor
Douglas W. Jackson, MD: What criteria constitute a subtrochanteric fracture?
Douglas W. Lundy, MD, FACS: Unfortunately, the definition of subtrochanteric femoral fractures is an area where there is not great precision or clarity of common language. The developers of the AO classification, Müller et al., used the subtrochanteric language only for proximal shaft fractures, but many surgeons in the United States have incorporated other proximal femoral fracture patterns into this grouping, including the reverse obliquity intertrochanteric fracture.
The common vernacular used in the United States includes many femoral fractures involving the lesser trochanter that extend proximally or distally, and the definition is not restricted to femoral fractures that only involve the shaft distal to the lesser trochanter. The Russell-Taylor classification system, noted in their 1992 textbook, illustrates this distinction by having a binary point that considers extension of the fracture into the piriformis fossa.
The issues with deformity, biomechanics and resuscitation are similar whether the definition is restricted to proximal femoral shaft fractures or if the pertrochanteric fractures are included. The commonly used definition of a subtrochanteric femoral fracture includes a spectrum of injury to the proximal femur.
The surgeon should endeavor to distinguish the subtrochanteric femoral fracture from the intertrochanteric fracture since the 135· screw-plate cannot adequately stabilize many subtrochanteric-type fractures.
Jackson: What special surgical techniques are needed to obtain adequate fixation of these fractures?
Lundy: Fixation of these fractures may be difficult due to the relatively small size of the proximal fragment, comminution of the fracture, poor bone quality due to osteoporosis, and the significant forces that cause fracture deformity.
The stability problems associated with the small size of the proximal fragment and poor bone quality can be overcome by the advanced fixation options that are currently commercially available.
Trochanteric starting-point nails with blades or multiple screws directed into the femoral head can produce a strong construct that maintains fracture reduction through the healing period. Proximal femoral plates with locking screw options also produce very stable fixation of these injuries.
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Certain fracture patterns can be well stabilized using the time-tested 95° plates. The 135° compression screw-plate is inappropriate for stabilization of subtrochanteric femoral fractures since they are not designed to resist the forces present in these fracture patterns.
The comminuted fragments often present in these fracture patterns may be fixed with interfragmentary screws that can be placed in bone corridors away from the nail or plate. The forces causing fracture deformity must be adequately addressed, or the fracture may be fixed in a malreduced position. The abducted position of the proximal fragment will cause a varus malreduction if not attended to, and the distal fragment must be aligned with the flexed position of the proximal fragment to avoid a flexion deformity in the fracture.
Jackson: What can be done to minimize the need for bone grafting?
Lundy: The surgeon should strive for a fracture reduction that is as perfect as possible. Certainly, a perfect reduction is not always possible nor practical when there is significant comminution present or if reduction maneuvers will damage the vascularity of the fragments. Indirect reduction techniques are preferable when stabilizing these injuries. The surgeon can utilize traction through a fracture table or by an assistant with the patient on the radiolucent table. The universal distractor can also be employed to apply reduction forces that will improve fracture reduction through the effects of the soft tissue envelope. The 1989 study by Kinast et al demonstrated that the use of indirect reduction techniques will reduce the need for bone grafting.
When the surgeon is treating a closed fracture that is extremely comminuted, such that there are obvious voids in the bone, immediate bone grafting may be advisable if this can be done through a technique that is atraumatic to the vascular supply to the proximal femur.
Iliac crest bone is a consistently excellent source for bone graft, but the use of bone graft substitutes and allograft bone is acceptable as well. The surgeon may want to consider improving the osteoinduction of the bone graft substitute by adding demineralized matrix.
Jackson: What can be done to minimize the loss of fixation and/or malunion?
Lundy: Careful attention to fracture reduction and fixation principles will lessen the incidence of loss of fixation and malunion. The surgeon should employ the fracture reduction techniques listed above and ensure that the fixation implants selected are capable of stabilizing the fracture.
When using intramedullary nails, the surgeon must remember that the fracture must be reduced while reaming. If the fracture is reamed in a malreduced position, it will be very difficult to obtain an acceptable reduction with the intramedullary nail.
Restricted weight-bearing after the surgery may be advantageous if there are concerns about the stability of the construct.
It is absolutely paramount that the surgeon search for and recognize problems in the post-operative period. If the fixation is demonstrating signs of failure, the surgeon should address this concern to the patient and formulate an appropriate plan. Returning to the operating suite for revision surgery may be indicated, but there may be times when this is inadvisable. The fracture may have been stabilized as well as possible, and there are times that fracture reduction may be impossible requiring an arthroplasty. The patient will often respect the surgeon for referring them on to a fracture specialist when post-operative issues arise if this referral is appropriate.
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Images: Lundy D |
For more information:
- Douglas W. Lundy, MD, FACS, is an orthopedic trauma surgeon, he can be reached at Resurgens Orthopaedics, Suite 1100, 61 Witcher, Marietta, GA 30060; 770-422-3290. e-mail: LundyDW@resurgens.com.
References:
- Kinast C, Bolhofner BR, Mast JW, Ganz R. Subtrochanteric fractures of the femur. Results of treatment with the 95 degrees condylar blade-plate. Clin Orthop Relat Res 1989;238:122-130.
- Müller ME, Nazarian S, Koch P, et al. The Comprehensive Classification of Fractures of Long Bones. Berlin, Germany: Springer-Verlag, 1990.
- Russell TA, Taylor JC. Subtrochanteric fractures of the femur, in Browner BD, Jupiter JB, Levine AM, Trafton PG (eds): Skeletal Trauma, Philadelphia, PA: Saunders, 1992.