Cemented vs Uncemented Bipolar Hemiarthroplasty for Intracapsular Fractures

Abstract

Background: Although there have been many comparisons done regarding Bipolar Hemiarthroplasty (BHA), which is often used for elderly patients with displaced intracapsular femoral neck fractures, there has still been considerable debate about the benefits of using cemented or press-fit femoral stems in this population. Cemented fixation provides the surgeon with the advantage of providing the strongest possible mechanical stability immediately after surgery, as well as decreasing post-operative pain; whereas, uncemented fixation avoids the use of cement, and therefore, decreases the risk of cement related cardiopulmonary complications. Therefore, we conducted a comparison of the clinical outcomes, functional scores and complications that occur when using either cemented versus uncemented BHA in an elderly population.

Materials and Methods: We completed a retrospective cohort study of elderly patients (age ≥ 60 years) who suffered from displaced intracapsular femoral neck fractures and underwent bipolar hemiarthroplasty between 2018 - 2020. The patients were grouped into two categories based on the type of femoral stem they received (cemented versus uncemented). There were no statistically significant differences in preoperative data collected (age, gender, ASA score, type of fracture) between the two groups. Primary outcomes studied included operative time, amount of blood lost during surgery, length of hospital stay, postoperative Harris Hip Scores (HHS), pain, and complications. Secondary outcomes studied included functional outcome, which was measured using the HHS at six months post-operatively, and complications (infection, dislocation, deep vein thrombosis (DVT), periprosthetic fracture, reoperation, and death) that occurred postoperatively. A two-sample t-test was utilized to compare continuous variables between the two groups, and a chi-squared test was utilized to assess differences in categorical variables between the two groups. Differences between the two groups were deemed to be statistically significant if the p-value associated with each statistical test was < .05. Institutional review board (IRB) approval and patient informed consent were both obtained prior to the completion of the study.

Results: There were fifty patients in each treatment group (mean age ~79 years, ~70% females). Statistically significant differences in the preoperative data collected (Table 1, p > .1) were observed between the two treatment groups. The patients that underwent cemented BHA experienced a longer operative time (120 ± 20 minutes) and greater blood loss (400 ± 100 ml) during their surgeries than the patients that underwent uncemented BHA (operative time = 90 ± 15 minutes, blood loss = 300 ± 80 ml, Table 2). However, the length of hospital stay for patients that underwent cemented BHA (5.5 ± 1.2 days) was not statistically significantly longer than the length of hospital stay for patients that underwent uncemented BHA (5.0 ± 1.0 days). At six months post-operatively, the mean HHS was statistically significantly higher for patients that underwent cemented BHA (85 ± 10) than it was for patients that underwent uncemented BHA (80 ± 12, Table 2). Additionally, patients that underwent cemented BHA reported a statistically significantly lower resting pain level (VAS = 1.5) than patients that underwent uncemented BHA (VAS = 2.0). The rate of surgical infections that occurred in patients that underwent cemented BHA (1/50) was statistically significantly lower than the rate of surgical infections that occurred in patients that underwent uncemented BHA (4/50, Table 3). The rates of dislocation and DVT that occurred in patients that underwent cemented BHA were statistically equivalent to the rates of dislocation and DVT that occurred in patients that underwent uncemented BHA. Furthermore, the rate of reoperations that occurred in patients that underwent cemented BHA (4%) was statistically equivalent to the rate of reoperations that occurred in patients that underwent uncemented BHA (10%). Finally, the rate of mortality at final follow-up for patients that underwent cemented BHA (4%) was statistically equivalent to the rate of mortality at final follow-up for patients that underwent uncemented BHA (6%).

Conclusion: In conclusion, our study demonstrated that cemented BHA yields slightly better mid-term function and lower pain levels with fewer infections and complications at the cost of longer surgeries and increased blood loss. Our results are consistent with those previously published randomized trials and meta-analyses that demonstrate that cemented femoral stems yield modestly superior hip function and less residual pain without increasing long-term mortality. Overall, both cemented and uncemented BHA produce acceptable outcomes for elderly patients with displaced intracapsular femoral neck fractures. However, because cemented fixation produces immediate strong mechanical stability, it may be preferred in patients with osteoporotic bone. Future prospective studies and long-term registries will continue to help provide recommendations for choosing the best implants for treating displaced intracapsular femoral neck fractures in the elderly.