Session III - Femur
*Expandable Intramedullary Nailing for Long Bone Fractures: Analysis of Results and Complications
Wade R. Smith, MD1 (d-Discotech Technologies); Bruce H. Ziran, MD2 (d-Discotech Technologies); Steven J. Morgan, MD1; Zachary Lahti1; Scott Lowe, MD3; Todd Vanderhagen3; Jacqueline J. Krumrey, MD1;
Introduction: Recent reports regarding the efficacy of expandable intramedullary nails in long bone fractures have emphasized the advantages to the patient and the surgeon of this novel technology. Because the nail inflates to fit the isthmus of the bone, there is an extensive interference fit, obviating the need for interlocking screws. Theoretically, operative time, blood loss, and incisions are reduced. Loss of reduction supposedly does not occur because of the inter-digitation of the external ribbing of the nail with the endosteum. Very little equipment is required for insertion, and inventory is significantly less than for standard nails because one size of nail can be inflated to fit a variety of canal diameters.
Hypothesis: Expandable nails would have a higher complication rate than reported for standard nails when used in lengthy unstable fractures and in fractures at the limits of the isthmus.
Methods: This prospective cohort series was conducted at two level I academic trauma centers. Additionally, we included all expandable nail procedures (FIXION, Disc Orthopedic Technologies) performed by local community orthopaedic surgeons during the study period. A designated senior traumatologist at each trauma center performed the nail procedures with resident staff. Initial demographic and intraoperative performance data were recorded. Patients were observed prospectively as outpatients. The primary outcome measures were the presence or absence of complications and time to healing.
Results: Seventy consecutive long bone fractures were treated with an expandable nail. Nails were inserted according to the manufacturer's suggested technique and inflated to 64 to 80 psi under fluoroscopic control. All fractures of the isthmus were included except OTA type C3. There were 23 femoral fractures, 27 tibial fractures, and 20 humeral fractures; 14 fractures were comminuted and considered of an unstable length. There were 13 open fractures and 57 closed fractures. Surgical time averaged 44 minutes for the femur, 36 minutes for the tibia, and 37 minutes for the humerus. Intraoperative fluoroscopic time averaged 1.6 minutes. Percutaneous entry incisions of less than 3 cm were used in all cases. External blood loss was minimal. Reaming was used in all cases except one femur and one tibia. Healing occurred in 55 (79%) patients without additional interventions. The overall union rate within 6 months was 96%. There were three nonunions and four delayed unions (three tibia fractures, one humerus). The average time to healing, excluding nonunion, was 15 weeks for the tibia, 13 weeks for the femur, and 16 weeks for the humerus. Nonunion occurred in two patients with a humeral fracture and one with a tibial fracture. Early hardware failure occurred as shortening greater than 2 cm in 12 cases (17%), significant nail deformation after a fall in 2 cases (3%), and occurred in length unstable fractures. Of the shortening cases, six were tibial fractures, four occurred in the femur, and two were humeri. Shortening occurred in a proportionately higher number of fractures of the proximal or distal third of the bone as opposed to the isthmus. In some cases, shortening occurred when length stable fractures became unstable due to fracture propagation and increased comminution. Such propagated fractures were not seen at the initial procedure and appear to have been due to nail expansion with the creation of occult cracks near the fracture site. Re-operation was required in 33% of the community hospital cases and 17% of the academic center cases. Overall, the expandable nail necessitated unplanned re-operation in 15 cases (21%).
Discussion: Expandable nailing is an attractive technology in that it does not require interlocking and allows for faster operations with less inventory. Advocates of expandable nails recommend their use primarily in length stable fractures of the isthmus. Additionally, placement of the nail is a simple and fast technique. The absence of interlocks and the ability to place a large diameter nail without reaming makes this technique particularly attractive to surgeons who perform a low volume of intramedullary nailing. However, we believe that, for a new technology to be useful, it should perform comparably to the current and well-published gold standard of reamed interlocked nailing. We placed nails in length unstable fractures as well as fractures at the limits of the isthmus in the femur, tibia, and humerus. We found that use of the expandable nail in this setting led to a high complication rate (21%), compared with previously published reports of standard nailing. Although expandable nails may work well in transverse or short oblique fractures of the isthmus, they should not be used in more comminuted patterns or for fractures extending beyond the isthmus. Furthermore, although fracture propagation has been described for conventional nails, their consequence is minor because with conventional nails, static interlocking is possible. In an expandable nail without interlocking capability, such fracture propagation cannot be adequately treated. This results in an unacceptable rate of failure and need for secondary procedures. Consequently, we determined that expandable nail technology without interlocking screws is not a replacement for standard nailing techniques at this time.
* If noted, the author indicates something of value received. The codes are identified as a-research or institutional support; b-miscellaneous funding; c-royalties; d-stock options and e-consultant or employee.