Alternatives In Fixation For Osteoporotic Bone
Given the decreased bone mineral density and poorer bone healing potential in people with osteoporosis, achieving adequate fixation can be challenging for osteotomies or arthrodesis procedures in this patient population. Accordingly, these authors review the literature and assess a range of fixation options including traditional plate fixation, cannulated screws and locking compression plates.
Today’s foot and ankle surgeons have at their disposal an abundance of osseous fixation methods and devices. Each of these various techniques offers both advantages and disadvantages depending upon the surgical scenario.
Patients with osteoporotic bone specifically represent an inherently challenging surgical experience. Surgeons must consider this pathology when selecting the type of fixation they will utilize. In addition to this being a consideration for osteotomy/arthrodesis fixation as patients with osteoporotic bone are by default more likely to develop fractures, one must take into account fixation techniques. Another factor to keep in mind is the possibility of osteoporotic fractures. Although osteoporotic fractures classically occur in the vertebra, hip, and wrist, they can also occur in the more distal lower extremity.1,2
Current estimates suggest that approximately 10 million Americans have osteoporosis while another 33.6 million have low bone density. However, these estimates may be low.3,4 Traditionally, when one thinks of a patient presenting with osteoporosis, a thin, older female patient profile comes to mind. However, in addition to gender and age, a number of social factors such as poor diet, smoking, lack of physical activity and immobilization can predispose a patient to decreased bone mineral density and poorer bone healing potential.5 Furthermore, various metabolic and hormonal changes can also increase the risk of bony changes, and all of these factors can affect both men and women of any age.3
Osteoporosis is defined as a decrease in bone mass and strength with deterioration of bone tissue and subsequent changes in bony architecture. These factors cause an increased risk of fracture or poor bony healing outcomes. One can clinically diagnose osteoporosis when the bone mineral density of the hip or spine is less than or equal to 2.5 standard deviations below the normal mean. Osteopenia, on the other hand, is defined as 1 to 2.5 standard deviations below the normal bone density mean. Typically, the calcaneus is the indicator of bone mineral density for the entire foot.6
Individuals with osteoporotic bone are inherently at a high risk of developing fractures and historically have demonstrated poorer outcomes with conservative management of these fractures.7 Generally, conservative care requires immobilization and limited activity, both of which may be detrimental for long-term outcomes for the patient.
Keys To Successful Fixation Of Fractures
The utilization of plates and screws for osseous fixation is a classic and successful technique. However, using fixation with plates and screws involves an additional insult to the local osseous blood supply of the fracture/osteotomy and arthrodesis fragments. These disruptions to the local blood supply increase the risks of delayed union and infection.8 Patients with osteoporotic bone undergoing reconstructive and trauma procedures of the foot and ankle present unique challenges for foot and ankle surgeons.
Adequate reduction and utilization of stable fixation are key elements for the successful fixation of fractures. In particular for those patients with poor bone stock, researchers have determined that an early return to activity postoperatively results in improved outcomes.9 Researchers have also linked longer periods of non-weightbearing to additional decreases in bone mineral density. Conversely, research has shown that an earlier return to weightbearing with load-bearing exercise improves bone density.6