NATIONAL UTILISATION TRENDS AND PERI-OPERATIVE OUTCOMES FOR TOTAL HIP ARTHROPLASTY VERSUS HEMIARTHROPLASTY FOR FEMORAL NECK FRACTURES

Summary Statement Total hip arthroplasty and hemi-arthroplasty are becoming increasingly popular in the treatment of femoral neck fractures in the United States. Both appear to be safe and effective treatment options, with rare acute adverse events and low mortality. Introduction Femoral neck fractures are one of the most frequent orthopaedic injuries seen in the United States (US). Total hip arthroplasty (THA) and hemiarthroplasty (HA) are commonly used to treat displaced intra-capsular femoral neck fractures, but controversy currently exists regarding the preferred modality. The purpose of this study was to assess recent national trends in THA and HA performed for femoral neck fracture and to evaluate perioperative outcomes for each treatment group. Methods International Classification of Disease - 9th Revision (ICD-9) diagnosis codes were used to search the National Hospital Discharge Survey (NHDS) for all patients admitted to US hospitals after femoral neck fracture for each year between 2001 and 2010. ICD-9 procedure codes were then used to identify patients from this fracture population who underwent THA or HA. Data regarding patient demographics, hospitalization length, discharge disposition, in-hospital adverse events (pulmonary embolus, deep vein thrombosis, blood transfusion, mortality) and hospital size/location were gathered from the NHDS. Trends were evaluated by linear regression with Pearson's correlation coefficient (r) and statistical comparisons were made using Student's t-test, z-test for proportions, and chi-square analysis with a significance level of 0.05. Results 12,757 patients with a femoral neck fracture were identified. 582 (4.6%) were treated with THA and 6,697 (52.5%) received HA. After adjusting for fluctuations in annual fracture incidence, the use of THA to treat femoral neck fractures demonstrated a strong positive correlation with time (r=0.91), significantly increasing from an average rate of 4.2% between 2001–2005 to 5.0% between 2006–2010 (p=0.04). Similarly, the use of HA demonstrated a strong positive correlation with time (r=0.89) and significantly increased from an average rate of 51.0% to 54.7% (p<0.01). The frequency of THA use also demonstrated significant (p=0.01) differences based on US region, with a rate of 3.3% in the West region and 5.2% in the South. No regional differences were seen for HA (p=0.07). Hospital size significantly impacted HA use, with the lowest rate seen in hospitals under 100 beds (47.4%) and the highest rate in those with 200–299 beds (56.0%, p<0.01). No size differences were seen for THA (p=0.10). The THA group had a mean patient age of 76.9 years and included 164 men and 418 women. The HA group had a mean patient age that was significantly higher at 81.1 years (p<0.01) and included 1744 men and 4953 women. Gender was not significantly different (p=0.27) between the groups. Average hospitalization length was significantly longer for THA (7.8 days, range 1–312) compared to HA (6.7 days, range 1–118, p<0.01). Discharge disposition also varied by treatment group, with 23.2% of THA patients able to go directly home compared to only 11.6% of HA patients (p<0.01). Blood transfusion rate was significantly higher for THA (30.4%) compared to HA (25.7%, p=0.02). No significant difference was noted between THA and HA in regards to rate of PE (0.5% versus 0.7%, p=0.52), rate of DVT (1.2% versus 0.8%, p=0.50) or mortality (1.8% versus 2.9%, p=0.09). Discussion/Conclusion This study demonstrates that the use of THA and HA in the treatment of femoral neck fractures are rising and that both are safe and effective treatment options, with equally rare acute adverse events and low mortality. Interestingly, treatment choice demonstrated variability based on hospital region and size. The reasons for this are not immediately clear, but may be related to differences in regional training and availability of trauma/reconstruction subspecialists.