The use of uncemented stems in femoral neck fractures in elderly patients: A comparative study of 671 cases.

INTRODUCTION: The use of cemented stems in elderly patients is associated with the risk of intraoperative embolic complications. Uncemented stems eliminate this risk, but their use is controversial because of the risk of mechanical complications, with estimated subsidence between 3.6 and 30% and periprosthetic fractures between 2.1 and 11% at 6 weeks. A retrospective multicenter comparative study was conducted using a propensity score analysis to evaluate mechanical performances of uncemented stems in femoral neck fractures in elderly patients to (1) compare the risk of mechanical complications and (2) assess the use of metaphyseal-anchored stems for this indication. HYPOTHESIS: There is no difference in the risk of mechanical complications, intraoperatively or postoperatively, between these stems. MATERIALS AND METHODS: We conducted a multicenter retrospective comparative study including 358 uncemented and 313 cemented stems. The mean age was 84.5 years [83.9-85.1]. The inclusion criteria were patients 70 years and older and a follow-up of at least 6 weeks. The primary endpoint was a composite endpoint comprised of stem subsidence≥2mm or periprosthetic fracture (up to 3 months postoperatively). The secondary endpoints were infection, stem subsidence≥2mm, and operative time. These endpoints were analyzed using a propensity score to control confounding factors. A secondary analysis used the same endpoints to compare metaphyseal-anchored (short stems) versus Corail-like stems. RESULTS: After adjusting for the propensity score, we found 11.17% mechanical complications in the uncemented group (n=40, 5.59% subsidence, and 5.59% fractures) versus 13.42% for the cemented group (n=42, 7.99% subsidence, and 5.43% fractures). There was no statistically significant difference between the 2 values (Odds Ratio [OR]=0.64 [95% Confidence Interval [CI]: 0.14-2.85] [p=0.7]). The mortality rate due to cement embolism was 1%. There was no difference in the rate of subsidence (OR=0.55 [95% CI: 0.02-12.5] [p=0.7]), periprosthetic fracture (OR=0.65 [95% CI: 0.13-3.12] [p=0.7]) or infection (OR=0.71 [95% CI: 0.32-1.55] [p=0.4]). However, the operative times were longer in the cemented group (p=0.03 for hemiarthroplasties [mean additional time 16minutes] and p=0.02 for total hip arthroplasties [mean additional time 22minutes]). No difference was observed between the metaphyseal-anchored (short stems) and Corail-like stems regarding operative time, rate of infection, and rate of stem subsidence or periprosthetic fractures. DISCUSSION: This is one of the first studies to highlight cemented stem subsidence when used for femoral neck fractures in elderly patients. Using uncemented stems in this indication is still warranted, especially since they do not bring about more mechanical complications in the first few months. Metaphyseal-anchored short stems seem to give the same results as "standard" stems. However, these findings need to be assessed in the longer term. LEVEL OF EVIDENCE: III; retrospective comparative study.

Subcostal TAP block: one or two sequential injections? A cadaveric study.

BACKGROUND AND OBJECTIVES: The subcostal transversus abdominis plane block (scTAPB) provides analgesia to the anterior abdominal wall but analgesic spread following a single injection remains modest and variable. The oblique scTAPB, which is performed with a continuous injection during needle progression into the TAP along the oblique subcostal line, may extend the block to the whole anterior abdominal wall but needle progression by hydrodissection may be difficult, explaining why this block is not widely used. This study investigated if two sequential scTAPB injections (2scTAPI) may reach more nerves than a single scTAPB (1scTAPI). METHODS: After institutional approval and under ultrasound guidance, a single injection of 20 mL of blue dye was performed in 16 cadaveric subjects into the TAP along the costal margin and lateral to the semilunaris line (1scTAPI). On the opposite side, a 20 mL of green solution was split into two injections (2scTAPI), using one injection medial and one lateral to the semilunaris line. Dye spread was assessed via gross anatomical dissection using an indirect method to quantify the involvement of the anterior cutaneous branches of the intercostal nerves with each technique. A nerve was considered stained if the dye was observed in the TAP, reaching the costal margin aligned with the bony extremity of its corresponding rib. RESULTS: According to the spread to the costal margin, the estimated median number of consecutive nerves reached by dye after 2scTAPI was 5 (IQR 5-6) vs 3 (IQR 3-4) for 1scTAPI (p=0.00001). Spread after 2scTAPI suggested coverage of nerves originating from T8 to T12 in 85% of the subjects, and from T7 to T12 in 5 out of 17 cases. Spread following the 1scTAPI suggested coverage of nerves from T9 to T11 in most cases. CONCLUSIONS: In a cadaveric model, a larger spread at the costal margin was obtained after 2scTAPI, suggesting a greater coverage of anterior branches of abdominal wall nerves compared with 1scTAPI. Clinical studies are needed to confirm these results.

A systemic mechanism of increased transendothelial migration of leukocytes through the blood-brain barrier in hepatic encephalopathy.

BACKGROUND: Hepatic encephalopathy (HE) is a frequent neurological complication of cirrhosis. Evidence suggests a synergic pathophysiological implication of hyperammonemia and systemic inflammation. In addition, the blood-brain barrier (BBB) permeability can be impaired in cirrhotic patients, notably in those displaying HE. We hypothesized that systemic inflammation could trigger leukocytes transendothelial migration (TEM) through the BBB in cirrhotic patients and especially those with HE. METHODS: We studied the effects of patients' plasma on the TEM of the leukocyte U937 cell line in vitro, using a validated BBB model (hCMEC/D3 cell line). We compared TEM of U937 leukocytes across hCMEC/D3 monolayer incubated with the plasma of i) patients with cirrhosis without HE, ii) patients with cirrhosis and HE, iii) healthy controls. RESULTS: We show that the plasma of cirrhotic patients with HE enhances TEM of U937 leukocytes across hCMEC/D3 BBB model. We found a correlation between U937 TEM on the one hand, the West-Haven score and ammonemia on the other one. A trend towards a correlation between U937 TEM and PS-100Beta in plasma, a marker of BBB solute's permeability increase, was also found. CONCLUSION: These findings suggest that circulating factors could increase leukocytes TEM in cirrhotic patients and contribute to the increased BBB permeability that has been described in cirrhotic patients with HE.

Cerebrospinal fluid metabolomics highlights dysregulation of energy metabolism in overt hepatic encephalopathy.

BACKGROUND & AIMS: Hepatic encephalopathy (HE) is a neurological complication observed in patients with liver disease and/or porto-systemic shunt. The proportion of cirrhotic patients developing overt HE is about 20%, and 60-80% of cirrhotic patients exhibit mild cognitive impairment potentially related to minimal HE. However, the pathophysiological mechanisms of HE remain poorly understood. In this context, metabolomics was used to highlight dysfunction of metabolic pathways in cerebrospinal fluid (CSF) samples of patients suffering from HE. METHODS: CSF samples were collected in 27 control patients without any proven neurological disease and 14 patients with symptoms of HE. Plasma samples were obtained from control patients, and from cirrhotic patients with and without HE. Metabolomic analysis was performed using liquid chromatography coupled to high-resolution mass spectrometry. RESULTS: Concentrations of 73 CSF metabolites, including amino acids, acylcarnitines, bile acids and nucleosides, were altered in HE patients. Accumulation of acetylated compounds, which could be due to a defect of the Krebs cycle in HE patients, is reported for the first time. Furthermore, analysis of plasma samples showed that concentrations of metabolites involved in ammonia, amino-acid and energy metabolism are specifically and significantly increased in CSF samples of HE patients. Lastly, several drugs were detected in CSF samples and could partially explain worsening of neurological symptoms for some patients. CONCLUSION: By enabling the simultaneous monitoring of a large set of metabolites in HE patients, CSF metabolomics highlighted alterations of metabolic pathways linked to energy metabolism that were not observed in plasma samples. LAY SUMMARY: CSF metabolomics provides a global picture of altered metabolic pathways in CSF samples of HE patients and highlights alterations of metabolic pathways linked to energy metabolism that are not observed in plasma samples.