Operative Fixation of Osteoporotic Fractures

Julie A. Switzer, M.D.
Assistant Professor, University of Minnesota
Director of Geriatric Trauma
Department of Orthopaedic Surgery

Although other aspects of the geriatric orthopaedic trauma patient, such as dementia, inadequate nutrition, and a reduced capacity for rehabilitation are important, none affects our ability to provide excellent care to this vulnerable population as much as the diminished bone quality of osteoporosis. Good fracture reduction and adequate implant fixation in osteoporotic bone, present profound challenges to our surgical skills.

Attention to detail is the rule during the approach and exposure. Surgery should be delayed until the soft tissue envelope is no longer compromised by edema, blisters, or broken skin. Handle fragile skin and soft tissues with care and keep periosteal stripping to a minimum. Use fingertraps and traction, for example, in dorsally angulated distal radius fractures before performing a reduction maneuver. Often, a reduction maneuver in these patients results in tearing of the tissue-paper like skin. Therefore, try the fingertraps with traction and/or an interfocal pinning technique prior to attempting to reduce the fracture with excessive force on the skin.

Try not to use self-retaining retractors; these can damage skin and soft tissue even though this may not be apparent until later on. Instead, have an assistant retract at the surgical site. Thus, when you are focusing on one area of the surgical field, the retraction and tension on the skin in the other areas can be relieved. Also, when employing forceps to hold the skin, use only the tine on the forceps inside the wound. The other tine that might normally be used on the skin should not be used to grip the fragile skin in these patients.

Prepare simple reduction tools, such as cylindrical rolls of drapery of various sizes or foam that has been formed to accommodate a limb. In a periprosthetic distal femur fracture, for example, the use of a roll at the fracture site can reduce the fracture and provide flexion at the otherwise extended fracture. Ask the scrub tech to create for you, using towels and Coban, three rolls one with a six inch diameter, another with an eight inch diameter and a third with a ten inch diameter. These can be changed during the procedure, depending on the degree of flexion necessary to reduce the fracture. Employing these simple measures outside the limb can eliminate the need for invasive reduction tools or excessive pressure on the skin and soft tissues.

When using bone reduction clamps, use ones that provide less penetration. A footed clamp or a pointed reduction clamp in concert with a small tubular plate that acts as a surface against which the force of the clamp is dispersed are nice instruments to use in a manner that reduce but do not crush osteoporotic bone (Figures 1 and 2).
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Figure 1
Footed bone reduction clamp.


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Figure 2
Footed bone reduction clamp with 1/3 tubular plate to disperse the pointed pressure from the clamp.

Highly comminuted osteoporotic fracture fragments should usually be spanned, as opposed to directly reduced. One method for fracture reduction in comminuted, osteoporotic distal fibula fractures, is as follows: fix the distal aspect of the plate to the distal fibula; expose the fibular periosteum proximal to the most proximal aspect of the plate; place a 3.5mm screw at this position; use a medium sized lamina spreader between the plate and the screw to distract at the fracture site; employ C-arm fluoroscopy to determine fibular length and degree of distraction necessary at the fracture; once adequate length has been restored, the proximal aspect of the plate is fixed to the bone.

Choice of implants is extremely important in osteoporotic fracture fixation. Few orthopaedic implant innovations have been as significant for a given population as locking plates have been in the geriatric population (Figure 3). Use of these implants, once fracture reduction has been achieved, will provide improved purchase and stability in osteoporotic bone1.

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Figures 3a & 3b
Healed periprosthetic distal femur fracture, fixed with a LISS locking plate. Note the unicortical screws proximally. With the exception of the most proximal screw, most locking screws in osteoporotic bone should actually be bicortical whenever possible.

Bicortical fixation with locking screws has been shown to improve purchase in osteoporotic bone2. Therefore, even though unicortical locking screws can be employed, in osteoporotic bone, bicortical locking screws should be the screw type of choice. The exception to this rule applies to the screw at the end of the plate to reduce the stress riser effect at the end of the plate, a unicortical locking screw should generally be placed through this last screw hole.

The use of intramedullary devices in osteoporotic bone allows load sharing in this population that does better with early mobilization. Although nails are commonly employed as singular devices, stacked K-wires or K-wires that create a cage-like construct, as described by Koval in fibula fractures, may provide intramedullary augmentation to plate fixation3. Additionally, using multiple K-wires, as opposed, for example to just two in standard medial malleolus fixation, provides for improved purchase (Figure 4).

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Figure 4
In this patient, various methods of fixation that can be especially helpful in osteoporotic bone were employed: multiple K-wires in the medial malleolus; K-wire plate augmentation in the fibula; syndesmotic fixation in the setting of osteoporosis rather than syndesmotic disruption; and tension band wiring of the medial malleolus.

Finally, innovation is important. Employing techniques or methods of fracture fixation not usually applied in a given setting might be just right in the osteoporotic fracture. One example of this is the use of syndesmotic screws in comminuted lateral malleoli fractures in the elderly. These screws, placed proximal to the comminuted fibular segment, may augment stability and prevent loss of plate fixation of the fracture.

Another example of innovation in osteoporotic bone fixation is the use of a tension band construct in regions not characteristically considered for this method of fixation. As seen in Figure 4, 18 gauge wire has been placed as a tension band capturing the end of a fan of K-wires placed through the medial malleolus fragment and capturing a metadiaphyseal screw. This gives support to the most medial cortex and prevents loss of the axial K-wire fixation. In two-part proximal humerus fractures in the elderly, instead of performing open reduction and internal fixation with any of the newer locking plates or even tension band wiring with metal implants, Banco et al. have shown good results with the following techniques: trim the lateral cortex of the humeral shaft; intussuscept the shaft into the head; position the humeral head in slight valgus; and provide fixation with Dacron tape. This can result in impressive outcomes in these difficult fractures4 (Figures 5 and 6).

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Figures 5 & 6
Reprinted with permission from JBJS from Banco et al: The Parachute Technique: Valgus Impacted Osteotomy for Two-Part Fractures of the Surgical Neck of the Humerus.

Fracture pattern in osteoporotic bone is often similar to fracture in normal, young bone. The quality of osteoporotic bone, however, presents challenges to our surgical skill, our choice of implant, and, most of all, to our attention to detail.

References

1) Wagner M. Injury. 2003 Nov;34 Suppl 2:B31-42.
2) Dougherty P.J., Kim D., Meisterling S., Yeni Y. 2005 OTA poster.
3) Koval K.J., Petraco D.M., Kummer F.J., Bharam S. J Orthop Trauma. 1997 Jan; 11(1):28-33.
4) Banco S.P., Andrisani D., Ramsey M., Frieman B., Fenlin J.M. Jr. J Bone Joint Surg Am. 2001; 83-A Suppl 2(Pt 1):38-42.

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