1 Introduction

The incidence and prevalence of hip fractures has been increasing globally over the past three decades, particularly among patient populations above the age of 55.¹ Falls remain the leading cause of hip fractures,² and osteoporotic patients present with a higher mortality risk.³ Surgical intervention remains the standard approach for managing these fractures, with closed reduction percutaneous pinning (CRPP) and hemiarthroplasty as common surgical options for treatment of femoral neck fractures.⁴ There remains a clinical debate in the selection between CRPP and hemiarthroplasty due to variances in patient comorbidities, complication rates, and postoperative recovery trajectories associated with each procedure.^4–8

Hemiarthroplasty is often favored for its lower failure and consequently lower reoperation rates and improved postoperative functional scoring and mobilization, particularly in elderly patients.^4,7 However, hemiarthroplasties have been reported to have increased surgical morbidity and a trend toward increased mortality in elderly patient populations.⁴ Comparatively, CRPP is preferred for nondisplaced fractures.⁹ Given its less invasive nature, CRPP is associated with shorter operative times, decreased blood loss, and shorter hospital length of stay,^4,7 but the procedure is associated with higher rates of reoperation – particularly in patients presenting with displaced hip fractures.¹⁰

The literature is inconclusive regarding patient outcome differences between hemiarthroplasty and CRPP, particularly regarding mortality and postoperative complications. For example, Dolatowski et al., concluded that in certain elderly patients with nondisplaced femoral neck fractures, hemiarthroplasty was not superior to internal fixation in reestablishing hip function but given the improved mobility and lower reoperation risk, hemiarthroplasty may be preferred to screw fixation.⁶ Lu et al., noted no difference in hip function between CRPP and hemiarthroplasty.¹¹ Furthermore, numerous studies reported no difference in mortality risk between hemiarthroplasty and CRPP.^4–6,11 Yet, other studies have reported a statistically significant higher mortality risk with hemiarthroplasty compared to CRPP.^12–14

To our knowledge, there is a lack of a single study that compares multiple complications and patient outcomes for CRPP versus hip hemiarthroplasty via a large multicenter database. Considering this and the contradictory literature surrounding hemiarthroplasty versus CRPP, a representative comparative analysis is essential to guide surgical decision-making and optimize patient-centered outcomes. The purpose of this study is to compare complication rates and patient outcomes – including mortality risk – between adult patients undergoing CRPP vs adult patients undergoing hip hemiarthroplasty, in a large, nationally representative patient population. We hypothesize that patients undergoing CRPP will have fewer perioperative/postoperative complications and lower mortality risk compared to patients undergoing hemiarthroplasty. We also hypothesize that hemiarthroplasty will have lower rates of complications necessitating return to the OR. We are optimistic that our findings will shed light on the nuances of procedure selection.

2 Methods

3 Results

4 Discussion

Hip fractures, particularly femoral neck fractures, represent a significant source of morbidity and mortality among elderly patients.¹⁸ Consequently, the surgical utilization of hemiarthroplasty and CRPP continues to increase, especially with an aging population and subsequent higher prevalence of hip fractures.^19,20 Given that hemiarthroplasty and CRPP are both associated with respective risks and postoperative complications, optimal procedure selection is critical in order to minimize adverse patient outcomes, particularly for vulnerable or elderly populations.^4,9

Patients undergoing hemiarthroplasty had a significantly higher risk of transfusion at both 30 days post-op and 90 days post-op compared to those receiving CRPP. Given that hemiarthroplasty is a more invasive procedure than CRPP,^4,21 this finding is consistent with our hypothesis and previous literature. Multiple studies have concluded that compared to CRPP, arthroplasty procedures result in greater blood loss.^8,22 Bhandari et al., surveyed an international cohort of surgeons and reported a preference towards arthroplasty in regards to expected functional outcome after surgical management of femoral neck fractures, although surgeons preferred CRPP when considering complications such as increased blood loss and surgical time.²² Our analysis is further supported by Guo et al., who concluded that hip hemiarthroplasty leads to a larger amount of blood loss than is observed during the operative period due to hidden blood loss comprising a significant portion of total blood loss.²³ This finding also helps explain our finding of significantly higher risk of blood loss anemia in hemiarthroplasty patients. Specifically, Konda et al., stated that fixation with CRPP can be safely performed as a substitute to hemiarthroplasty to stabilize displaced femoral neck fracture in those unable to tolerate anesthesia or the sequelae of major surgery. Moreover, incidence of acute blood loss anemia was less commonly observed in CRPP patients than hemiarthroplasty patients.²⁴

The risk of acute renal failure was significantly greater in the hemiarthroplasty group at 30 days and persisted at 90 days. This is in congruence with previous literature. It is well known that acute kidney injury (AKI) is a common complication of hip fracture surgery.²⁵ Jameson et al., reported that older patients – specifically patients aged ≥85 years –who were admitted for femoral neck fractures exhibited a greater incidence of acute events, such as AKI, following hemiarthroplasty.²⁶ The average age of our hemiarthroplasty cohort was 72.3 ± 17.8 and, although lower than our CRPP cohort, classifies as elderly. Additionally, hemiarthroplasty is a more invasive procedure than CRPP⁴ and in response to surgical stress, the body increases systemic inflammation predisposing these patients to organ failure and sepsis.^24,27 Another study noted significant correlations between peak levels of pro-inflammatory cytokine interleukin-6 and C-reactive protein and estimated complication rate after hip arthroplasty.²⁸ This study also helps to explain our finding that hemiarthroplasty patients were at a higher risk for wound dehiscence at both 30 days and 90 days. Therefore, the greater risk of acute renal failure and wound dehiscence for hemiarthroplasty may reflect the heightened physiological stress and inflammatory response associated with the more invasive nature and larger surgical exposure required for hemiarthroplasty.

Periprosthetic joint infection (PJI) rates were notably higher following hemiarthroplasty at 30 days and 90 days. These findings are consistent with previous literature. Sumi et al., studied risk factors of PJI after hemiarthroplasty for displaced femoral neck fractures and concluded that blood transfusion and hematoma were significantly related to an increased risk of PJI.²⁹ We found higher rates of blood transfusion in our hemiarthroplasty cohort, supporting the observed increased risk of PJI in the same cohort. Interestingly, we found that hemiarthroplasty and CRPP patient cohorts had similar rates of hematoma. Furthermore, a 2019 study in the Journal of Arthroplasty reported that the risk of PJI increased by 25 % for every additional 20 min of operative time. Also, individuals who had operations longer than 90 min had a twofold increased risk of having SSI.³⁰ Although we did not find increased rates of SSI in hemiarthroplasty patients, prolonged surgical times of hemiarthroplasty could explain our observed higher rates of PJI.

We also observed a higher risk for pulmonary embolism (PE) in the hemiarthroplasty cohort at 30 days and 90 days. Hemiarthroplasty has been previously established as an independent risk factor for symptomatic PE.³¹ Wu et al., concluded that PE risk is high in hemiarthroplasty secondary to its invasive nature and greater disruption of tissues and blood vessels in the hip area. This disruption can increase the release of thrombogenic substances and promote venous stasis, contributing to PE.³² Additionally, blood transfusions have independent associations with increased thromboembolism and consequent PE risk.³³ Hence, our finding of increased blood transfusion risk in hemiarthroplasty patients can help explain the increased PE risk compared to CRPP cohort. Lastly, the shorter hospital stays associated with CRPP⁴ support our observed lower rates of PE as hospital length of stay is associated with increased likelihood thromboembolism.³⁴

We found a higher risk of short-term and long-term mortality in hemiarthroplasty patients compared to CRPP patients. This disagrees with some previous literature. Griffin et al., found no significant difference between CRPP and hemiarthroplasty in regard to mortality within the 60s and 70s age groups.⁴ Two meta-analyses both concluded that mortality rates were not different between patients undergoing arthroplasty vs internal fixation.^5,7 However, there is literature that supports both hypotheses: no difference in mortality between CRPP and hemiarthroplasty, as well as lower mortality with CRPP.⁴ Our findings can be explained by previously mentioned more severe surgical trauma, intraoperative blood loss, and increased PJI risk associated with hemiarthroplasty.^23,35 For example, PJI was associated with significantly higher 1-year mortality.³⁵ Furthermore, PE complications could have contributed to mortality.³⁴ Additional research is warranted to understand the mechanisms behind the mortality risk of hemiarthroplasty.

Although we did not find differences in our subgroup analysis, given that hemiarthroplasty is associated with more complications and is more invasive in nature, CRPP may be a better option for vulnerable patients.³⁶ However, thorough consideration of patient factors and goals are warranted when deciding between these two procedures. For example, Kahlenberg et al., concluded that even though CRPP is a successful procedure for older patients and individuals with specific comorbidities, its failure rate was significantly higher than the failure rates for arthroplasty in the same demographic. Patients who are being evaluated for CRPP and have femoral neck fractures, therefore, should be advised about the potential for future surgery.⁸

5 Limitations and strengths

The limitations of this study largely stem from its retrospective design and reliance on data sourced from electronic health records (EHRs), which are vulnerable to errors in coding and documentation. The use of the TriNetX database, a voluntary registry, introduces the potential for selection bias due to the overrepresentation of large academic medical centers. Consequently, the findings may not be generalizable to all patient populations worldwide. Additionally, this study could not adjust for key socioeconomic factors such as health insurance status, education level, or income, which we recognize as important contributors to surgical outcomes.

The lack of direct reporting on reoperation rates within TriNetX is a limitation, especially since it is a big factor when selecting between hemiarthroplasty and CRPP. Moreover, we recognize that since there are various types of femoral neck fractures, it is a possibility that many cases in this study may not have initially been indicated for both hemiarthroplasty and CRPP. Also, total hip arthroplasty is a common surgical option for femoral neck fractures¹⁹ – a procedure we did not study, which may have inadvertently reduced our cohort numbers. Given that the dataset includes information from diverse medical practices across the United States, Western Europe, and Canada, it is likely that there was variability in surgical techniques, equipment, complication reporting, and postoperative care protocols. Retrospective studies also depend on the accuracy of data recorded by medical personnel, which may have influenced our results and interpretations. However, the large sample size in this study strengthens its statistical power and allows for more reliable estimation of rare complications. In addition, because the study authors were not involved in the surgical procedures and all patient data were de-identified, the potential for bias in data collection and analysis was minimized, further bolstering the study's reliability.

Despite these limitations, the study has several notable strengths, most prominently the ability to analyze a large, matched cohort of patients undergoing either CRPP or hemiarthroplasty. By accounting for demographic factors and comorbidities, this analysis offers valuable insights into the comparative outcomes of these procedures. To the best of our knowledge, this is the largest known patient cohort comparing CRPP patient outcomes with hemiarthroplasty patient outcomes.

6 Conclusion

This study highlights important differences in clinical outcomes between hemiarthroplasty and closed reduction percutaneous pinning (CRPP) for the treatment of hip fractures. At 30 days following surgery, hemiarthroplasty was associated with a higher risk of transfusion, pulmonary embolism, and periprosthetic joint infection compared to CRPP. At 90 days, hemiarthroplasty patients experienced a greater risk of acute posthemorrhagic anemia, superficial surgical site infections, and periprosthetic dislocation. No significant differences were observed at 30 days or 90 days between hemiarthroplasty and CRPP for MI, hematoma, and pneumonia. No significant differences were observed between hemiarthroplasty and CRPP in the subgroup analysis of dialysis CKD 5 patients. Future studies should examine the complications of hemiarthroplasty and CRPP with other vulnerable patient populations and aim for long-term follow-up and with a large, representative patient population.

CRediT authorship contribution statement

Anubhav Thapaliya: Writing: Data processing, Data curation, Validation, Writing – original draft, Writing – review & editing, Visualization. Paul Gudmundsson: Writing – review & editing. Benjamin Montanez: Writing – review & editing. Varatharaj Mounasamy: Conceptualization, Supervision, Writing – review & editing. Senthil Sambandam: Conceptualization, Methodology, Data curation, Writing – review & editing, Supervision, Project administration.

Disclosures

The authors do not have conflicts of interest to report. This research did not receive any specific grant from funding agencies in the public, commercial or not-for-profit sectors. There are no further acknowledgements. This study was exempt from IRB approval since the data was de-identified and publicly available.

Consent

Our study, Hip Hemiarthroplasty versus Closed Reduction Percutaneous Pinning: A Matched Cohort Analysis of 18,242 Patients, obtained information from a national database where the data is de-identified and publicly available, therefore no consent process was required.

Ethical approval

Regarding ethical committee approval, our study (Hip Hemiarthroplasty versus Closed Reduction Percutaneous Pinning: A Matched Cohort Analysis of 18,242 Patients) was exempt from IRB approval since the data was de-identified and publicly available.

Funding

Our study, Hip Hemiarthroplasty versus Closed Reduction Percutaneous Pinning: A Matched Cohort Analysis of 18,242 Patients, did not have any sources of funding. No funding was received to assist with the preparation of this manuscript.