Validation of a prospective mortality prediction score for hip fracture patients.

PURPOSE: Although mortality prediction tools are the subject of significant interest as components of comprehensive hip fracture protocols, few have been applied or validated to prospectively inform ongoing patient management. Five regional hospitals are currently generating real-time mortality risk scores for all adults at the time of admission using available laboratory and comorbidity data (Cowen et al. J Hosp Med 9(11):720-726, 2014). Although results for aggregated conditions have been published, the primary aim of this study is to determine how well prospectively calculated scores predict mortality for hip fracture patients specifically. METHODS: Using a five-hospital database, 1376 patients who were prospectively scored on admission were identified from January 2013 to April 2017, cross-referencing ICD9/10 diagnosis and procedure codes for AO/OTA 31A1 through 31B3 fractures. Prospective mortality scores have been previously divided into 5 risk categories to facilitate ease of clinical use. Vital status was determined from hospital data, Social Security and Michigan Death Indices. RESULTS: Prospective scores demonstrated good mortality prediction, with AUCs of 0.80, 0.73, 0.74 and 0.74 for in hospital, 30-, 60- and 90-day mortality, respectively. Patients in the top 2 mortality risk categories represented 30% (410/1376) of the cohort and accounted for 78% (25/32) of the inpatient and 59% (57/97) of the 30 day deaths. CONCLUSIONS: Implementation of this real-time mortality risk tool is feasible and valid for the prediction of short- to medium-term mortality risk for hip fracture patients, and potentially offers valuable information to guide ongoing patient management decisions such as admitting service or level of care.

Review of Therapeutic Options for the Prevention of VTE in Total Joint Arthroplasty.

Hip and knee arthroplasty patients are at high risk of perioperative venous thromboembolic events (VTE). VTE has been well studied in this population and it is recommended that total joint arthroplasty recipients receive chemoprophylactic anticoagulation due to risk factors inherent to the surgical intervention. There are few concise resources for the orthopedic surgeon that summarize data regarding post-operative anticoagulation in the context of currently available therapeutic options and perioperative standards of practice. The periodic reexamination of literature is essential as conclusions drawn from studies predating perioperative protocols that include early mobilization and sequential compression devices as standards of practice in total joint arthroplasty are no longer generalizable to modern-day practice. We reviewed a large number of recently published research studies related to post-operative anticoagulation in total joint arthroplasty populations that received a high Level of Evidence grade. Current literature supports the use of oral aspirin regimens in place of more aggressive anticoagulants, particularly among low risk patients. Oral aspirin regimens appear to have the additional benefit of lower rates of bleeding and wound complications. Less consensus exists among high risk patients and more potent anticoagulants may be indicated. However, available evidence does not demonstrate clear superiority among current options, all of which may place patients at a higher risk of bleeding and wound complications. In this situation, chemoprophylactic selection should reflect specific patient needs and characteristics.

Age and dressing type as independent predictors of post-operative infection in patients with acute compartment syndrome of the lower leg.

PURPOSE: The purpose of this study was to determine independent factors, including timing of fasciotomy, that confer an increased risk of post-operative surgical site infection (SSI) in patients presenting with acute compartment syndrome (ACS) of the lower extremity. METHODS: A retrospective analysis was performed on a consecutive cohort of 53 adult patients requiring fasciotomy for lower-extremity fractures complicated by ACS presenting to a single Level I trauma center over a seven-year study period. The primary outcome measure was the incidence of SSI (as defined by the CDC) occurring within 12 months of fasciotomy. Explanatory variables including site of ACS, time of injury, time of fasciotomy, operative findings, and requirement for additional soft tissue coverage procedures were recorded for all patients. Multivariate regression was used to determine independent predictors of post-operative SSI. RESULTS: post-operative SSI was detected in 16 (30.2%) patients. Compared to infection-free patients, patients with post-operative SSI had a significantly higher median age (52.0 vs. 37.0 years, p = 0.010), frequency of intra-operative myonecrosis at time of fasciotomy (31.2% vs. 5.4%, p = 0.021), and requirement for negative-pressure wound therapy [NPWT] (93.7% vs. 45.9%, p = 0.002). Multivariate logistic regression analysis confirmed that requirement for NPWT (odds ratio [OR], 17.10; 95% confidence interval [CI], 1.78-164.0; p = 0.014) and increasing age (OR, 1.07; 95% CI, 1.01-1.14; p = 0.037) were independent predictors of post-operative SSI. Timing of fasciotomy following injury was not independently related to the risk of SSI. CONCLUSIONS: ACS occurs on a spectrum of disease severity that evolves variably over time. Increasing age of the patient and requirement for NPWT following fasciotomy are independent predictors of post-operative SSI following emergent fasciotomy for ACS. Further studies are required to inform optimal treatment strategies in such patients. LEVEL OF EVIDENCE: Therapeutic, Level III.

Rotational alignment of the knee is different in osteological specimens with and without a large cam deformity of the proximal femur.

PURPOSE: We studied a large osteological collection for differences in knee rotation based upon the presence or absence of a large cam deformity of the proximal femur. METHODS: We obtained 357 matched tibiae and femora from the Hamann-Todd Osteological Collection and measured: femoral head-neck alpha angle, anteroposterior axis (or Whiteside's line) at the distal femur relative to the posterior condylar axis, and position of the tibial tubercle with respect to the posterior condylar axis of the proximal tibia. We then divided these specimens into two groups based upon alpha angle <45° (Group 1, n = 73) or alpha angle >60° (Group 2, n = 122) and performed an independent samples t-test to evaluate for differences in measured parameters between groups using this subset of specimens. RESULTS: The mean alpha angles in Group 1 and 2 were 40.9° ± 3.3° and 67.0° ± 5.6°, respectively. Whiteside's line was externally rotated with respect to the posterior femoral condylar axis by a mean of 1.8° ± 6.8° in Group 1, vs. 3.0° ± 3.7° in Group 2 (p = 0.03). The tibial tubercle was externally rotated by a mean of 19.4° ± 6.8° in Group 1, versus 16.6° ± 5.1° in Group 2 (p = 0.003). CONCLUSIONS: Specimens with femoral head-neck alpha angle >60° demonstrated greater external rotation of the distal femur and a more internally-rotated tibial tubercle compared to specimens with an alpha angle <45°. Differences in anatomic characteristics of the knee may play a role in the development of patellofemoral pain in patients with a large cam deformity.

Fatigue and in vivo validation of a peritoneum-lined self-expanding nitinol stent-graft.

PURPOSE: To assess the fatigue and in vivo performance of a new stent-graft incorporating bovine peritoneum lining that is designed for application in peripheral vascular occlusive disease. METHODS: Bovine peritoneum-lined stent-grafts were subjected to accelerated in vitro pulsatile fatigue and axial/torsional fatigue testing designed to simulate 10 years of physiological strain on the devices. At specified times the devices were evaluated for stent fracture, suture failure, or tissue tearing. Seven dogs underwent bilateral common iliac artery (CIA) balloon angioplasty injury with unilateral placement of the peritoneum-lined stent-graft. Angiography and intravascular ultrasound were performed prior to treatment, after treatment, and prior to sacrifice at 30 days. Vessels were perfusion fixed and histologically evaluated at 5 regions: above stent, proximal stent, mid stent, distal stent, and below stent. RESULTS: No evidence of stent, suture, or tissue failure was present during or after pulsatile and axial/torsional fatigue testing. At 30±0.3 days after implantation, all vessels were patent. The average lumen area at explantation across stented vessels was 25.45 mm(2). Lumen areas tended to be reduced above (23.57 mm(2)) and below (24.17 mm(2)) the stent. Lumen areas were consistent across stented regions at explantation (proximal stent 27.80 mm(2), mid stent 25.88 mm(2), and distal stent 25.81 mm(2)). The mean neointimal area in peritoneum-lined stents was 2.02±1.52 mm(2), with a neointima:media ratio of 1.03±0.50. These values were significantly lower in the above and below stent areas than in the stented regions, but there was no difference in either measure within the proximal, mid, or distal stent. CONCLUSION: The custom-designed peritoneum-lined stent-graft is promising for clinical peripheral applications due to its ability to resist relevant long-term physiological stresses and outstanding short-term patency rates in canine implantations.

Macrophage depletion in the murine olfactory epithelium leads to increased neuronal death and decreased neurogenesis.

Apoptosis of olfactory sensory neurons (OSNs) induced by olfactory bulbectomy (OBX) leads to the activation of resident macrophages within the olfactory epithelium (OE). These macrophages phagocytose degenerating OSNs and secrete chemokines, which recruit additional macrophages into the OE, and cytokines/growth factors, which regulate basal cell proliferation and differentiation and maturation of OSNs. In this study we apply for the first time the use of liposome-encapsulated clodronate to selectively deplete macrophages during the OSN degeneration/regeneration cycle in order to elucidate the role(s) of macrophages in regulating cellular mechanisms that lead to apoptosis and neurogenesis. Mice were injected intranasally and intravenously with either liposome-encapsulated clodronate or empty liposomes prior to and after OBX or sham OBX. At 48 hours after surgery the numbers of macrophages in the OE of both sham and OBX clodronate-treated mice were significantly reduced compared to liposome-treated controls (38% and 35%, respectively, P < 0.05). The reduction in macrophage numbers was accompanied by significant decreases in OE thickness (22% and 21%, P < 0.05), the number of mOSNs (1.2- and 1.9-fold, P < 0.05), and basal cell proliferation (7.6- and 3.8-fold, P < 0.005) in sham and OBX mice, respectively, compared to liposome-treated controls. In OBX mice there was also increased immunoreactivity for active caspase-3 in the OE and olfactory nerves of clodronate-treated OBX mice compared to liposome-treated controls. These results indicate that macrophages modulate the OSN population in the normal and target-ablated murine OE by influencing neuronal survival and basal cell proliferation, resulting in neurogenesis and replacement of mature OSNs.