Does Knowledge of Implant Cost Affect Fixation Method Choice in the Management of Stable Intertrochanteric Hip Fractures?

Reclassification resulted in more A2.1 fractures (42.0% vs 37.0%) and fewer A1.3 fractures (10.1% vs 16.0%). About the same numbers of fractures were classified A1.1 (21.0% vs 21.8%) and A1.2 (26.9% vs 25.2%). SHS was favored for A1.1 fractures (92.0%) and A1.2 fractures (65.6%). SGN was favored for A1.3 fractures (75.0%). Gamma nails of both sizes were favored for A2.1 fractures (88.0%).

Discussion

Comparisons of SHS/plate and CMN constructs in the management of stable intertrochanteric hip fractures have long been discussed in the orthopedic literature. The major concern with CMNs (vs SHSs) is a statistically significantly higher rate of revision surgery, most often for peri-implant fracture. Rates of previous revision surgery for peri- implant fracture have ranged from 2.4% to 6% for CMNs and from 0.6% to 4% for SHSs.^5-7,9 In a Cochrane review of 22 studies (3749 patients), Parker and Handoll¹² compared CMN and SHS outcomes in 23 categories and found a statistically significant difference only in postoperative fracture rate. However, in a meta-analysis of studies conducted between 2000 and 2005, Bhandari and colleagues⁸ found no statistically significant difference in risk of femoral shaft fracture between CMNs (0.6%) and SHSs (0.1%). In addition, Utrilla and colleagues¹⁰ reported no postoperative fractures with use of Gamma3 CMNs. These recent studies may indicate that newer CMN designs can reduce the incidence of postoperative peri-implant fracture.^8,10 Other outcome measures, such as 1-year mortality, functional outcome, and medical complication rate, have shown no statistically significant differences between the 2 implants.^10-12 Ultimately, the current recommendation for fixation of stable intertrochanteric hip fractures is either SHS or CMN.^13,14

Of our study patients, 78.9% (before group) and 64.6% (after group) were female, and 49.3% (before group) and 47.9% (after group) were between 80 and 89 years of age. Similarly, a review of hip fracture Medicare claims made between 1999 and 2002 revealed that >75% of the patients were females and 48% to 49% were octogenarians.^4,18 However, our rates of different fracture types differed from those of Adams and colleagues.⁵ In a 1-year single-institution study, they found that, for both CMNs and SHSs, the most common stable intertrochanteric fractures were 31-A1.1 fractures; in our study’s before and after groups, more than one-third of injuries were 31-A2.1 fractures. Least common were 31-A1.3 fractures, both in the study by Adams and colleagues⁵ and in our before (16.9%) and after (14.6%) groups. Although our fracture rates differ from those of previous studies, all 4 classification categories fall under the umbrella of stable intertrochanteric hip fracture, which is the sole focus of this study.¹⁴ 

We hypothesized that cost would be a significant driver of implant choice in the management of these injuries. Given that SHS costs $1186.91 less than SGN and $1625.88 less than LGN at our institution, we expected that the before- discussion group’s overall SHS use rate of 38.0% would increase after discussion. Instead, SGN became the favored implant, with use in almost half of all fractures in the after group. Although the change in overall implant use rate was notable, these findings were not statistically significant. Examination of individual fracture patterns revealed 2 areas of interest. First, SHS was assumed to be the implant of choice in the management of the relatively simple 31-A1.1 fractures. Although this assumption was verified in the before group (SHS use in 43.8% of fractures), SGN was used in almost every case (90%) in the after group. However, when surgeons were asked 1 year later to recommend an implant for A1.1 fractures, 92% suggested SHS. The more cost-effective SHS construct may be the most amenable for use in these injury types given all intertrochanteric hip fracture patterns, though this has not been studied.

On the other hand, for 31-A2.1 fractures, perhaps the most complicated of the stable patterns, LGN became the implant of choice (42.1%). Despite surgeons’ awareness of the cost differences, management of these fractures shifted in the after group to the most expensive implant, indicative of surgeon concern about eventual loss of reduction with SHS and surgeon comfort with a particular procedure. This trend held when surgeons were asked to reclassify fractures 1 year later, as CMNs were recommended for 88% of 31-A2.1 fractures. Although both SHS and CMN were acceptable in 97% of the fractures included in this study, SGNs or LGNs were preferred for almost every fracture pattern involving the lesser trochanter. All 9 attending surgeons described involvement of the lesser trochanter as an indicator of posteromedial calcar injury. Surgeons became particularly concerned when this fracture pattern occurred in patients with significant osteopenia; SHS fixation, in their opinion, would be poor in the setting of a combination of greater posteromedial instability and poor bone quality. In a level I prospective, randomized trial, Barton and colleagues⁷ found no difference in outcomes between LGN and SHS fixation for 31-A2 proximal femur fractures and recommended SHS implants for the cost savings. In the clinical experience of this group, however, A1.3 and A2.1 fractures were at especially high risk for failure with SHS use, which necessitated greater implant stability through CMN fixation. On the other hand, for simpler fracture patterns, most surgeons suggested SHS implants. In their opinion, SGN and LGN implants offered no additional benefit of stability without evidence of posteromedial injury, even in the setting of osteopenia. For A1.2 fractures, posteromedial involvement was judged on the basis of size of the inferomedial spike or the extent of the inferomedial fracture line. Two surgeons preferred CMN for simple fractures, one because of the increased comfort with the implants and the other because of the minimally invasive surgical technique. Overall, our results indicate that knowledge of implant cost is not a strong enough factor to change surgeon behavior in selecting fixation for uncomplicated stable intertrochanteric hip fractures in previously ambulatory elderly patients. 

The lack of effect could be a consequence of surgeons’ training and comfort with various implants, especially among younger attending surgeons. Most of the attendings in the practice are under age 50 years, which correlates with a preference for CMN fixation.¹⁹ Case loads of >80 intertrochanteric hip fractures per calendar year, as in the after group, also correlates with more CMN use.¹⁹ However, the before group had more intertrochanteric hip fractures, and yet SHS was the implant of choice. Resident physician experience and comfort with various implants may play a role too, as teaching hospitals with resident assistance also correlate with CMN use.¹⁹ However, no major change in resident physician involvement was undertaken during this period. The institution studied is near a major metropolis in the Northeast, a region that has disfavored SHS in recent years.¹⁸ The change from before to after fits an overall trend in changing implant use. Anglen and colleagues¹⁵ found a significant decrease in SHS use, from 97% in 1999 to 33% in 2006, for intertrochanteric fracture fixation. Simultaneously, CMN use increased from 3% to 67%.

This study had several limitations. First, its overall sample size was small, and therefore any data fluctuations may be exaggerated. Furthermore, changes in utilization rates were compared over 2 years, which may not be long enough to show a changing trend in implant selection. Post hoc analysis of the sample size determined a power of 0.76 for an α of 0.05 and an effect size of 0.50. Second, radiologic classification was performed in a retrospective review, not officially by the operative surgeon. Fractures that we considered stable may have been considered unstable by the operative surgeon, influencing implant selection. Third, patients were selected from only one hospital, and orthopedic surgeons from other institutions may be more sensitive to cost considerations, changing implant selection more quickly. Fourth, initial selection of patients by CPT code might not have captured all those who satisfied the inclusion criteria. Fifth, only a single intervention was used, and follow-up meetings certainly could have increased the effectiveness of the intervention. Last, this and other retrospective studies are inherently weaker because of possible bias.

Conclusion

Our study results showed that implant cost is not a significant factor in implant selection for uncomplicated stable intertrochanteric hip fractures in previously ambulatory elderly patients. By itself, knowledge of implant cost may not be a strong enough force to change surgeon behavior or preference secondary to consequences of failure or comfort with particular implants. In an economic climate in which healthcare is scrutinized for both its medical effectiveness and cost-effectiveness, further study of forces that could influence orthopedic surgeons to select a more cost-effective implant is warranted.