Bone Density by Specific Anatomic Location Using Hounsfield Samples of the Lower Extremity: A Multi-center Retrospective Analysis.

Understanding bone mineral density and its effects on patient outcomes is a useful tool for lower extremity surgeons. Historically, dual-energy X-ray absorptiometry scans have been the gold standard for quantifying bone mineral density. In this study, we look at an indirect way to measure bone mineral density using Hounsfield units on computed tomography. The aim of this study is to establish normal physiological Hounsfield ranges in specific bones of the foot by analyzing Hounsfield unit measurements and determining associated factors. We hypothesize that there will be a difference in density based on age, sex, and anatomic location. Patient data from January 2010 to January 2020 were retrospectively analyzed from 2 institutions. Nine anatomic locations (calcaneus, talar body, talar head, navicular, cuboid, medial cuneiform, head of first and fifth metatarsal, and base of first proximal phalanx) were measured for bone mineral density averages. In total, 137 patients were evaluated (71 males, 66 females) with an average age of 54 years. Significant differences in density were found between the 9 anatomic locations. Age was confirmed to be a significant covariate with inverse relation to Hounsfield units, p < .001. There were no density differences between sexes at any of the locations, except the talar head, p < .001. This is the first study to our knowledge to establish normal physiological ranges of bone density on computed tomography for specific anatomic locations of the foot. This quantitative approach to bone density and the established effect of age, sex, and location is pivotal for diagnostic and preoperative planning.

Clinical Outcomes for Pilon Variant Posterior Malleolar Fractures: A Multicenter Retrospective Analysis.

Currently, there is no consensus on surgical approach for posterior malleolar fracture fragments with significant posteromedial involvement. The Bartonicek type III/Haraguchi type II posterior malleolar morphologies typically involve large posteromedial fragments, behaving like a pilon injury and have been reported as pilon variant fractures. We performed a retrospective chart review at 2 large healthcare institutions, evaluating patients that underwent surgical management of pilon variant posterior malleolar fractures and determining clinical outcomes including: time to union, union rates, soft tissue complications, infection and time to weight bearing. A total of 68 patients were included (51 females, 17 males). A total of 51 direct (19 posterolateral, 31 posteromedial), 6 indirect, and 11 no-fixation approaches were identified. Significantly different time-to-union was found between direct fixation (mean = 85.1 days), indirect fixation (mean = 74 days) and no-fixation (mean = 174.3 days) (p < .001). A posteromedial approach (mean = 63.0 days, SD = 16.6) was associated with significantly shorter time to union when compared to a posterolateral approach (mean = 124.8 days, SD = 59.4; p < .001). Fixation (direct or indirect) was associated with significantly increased likelihood of union of the overall ankle fracture pattern (52/57 = 91%) when compared to no fixation of the posterior malleolar component (9/14 = 64%), p = .01. Patients who underwent direct fixation had significantly lower incidence of neurovascular damage (6%) when compared to patients who underwent indirect fixation (33%) or no-fixation (29%) (p = .02). There was no significant difference between the groups in terms of tendon damage (p = .54), infection rates (p = .45) and time to weight bearing (p = .66). The authors suggest that surgical management and specifically direct approaches have better outcomes in the short-term follow up.

A Systematic Review and Meta-Analysis of the Effectiveness of LRINEC Score for Predicting Upper and Lower Extremity Necrotizing Fasciitis.

This review and meta-analysis aims to assess the prognostic value of the Laboratory Risk Indicator for Necrotizing Fasciitis (LRINEC) score for detecting necrotizing fasciitis in the extremities. The LRINEC score has been validated in multiple studies as a clinical tool for differentiating necrotizing fasciitis from non-necrotizing infections however many studies do not specify the location of infection. As the prevalence of diabetes and diabetic foot infections continues to rise, the utility of LRINEC scores in these populations becomes of increased importance. Four databases were reviewed for citations between January 2010 and December 2020. English, full text articles reporting the diagnostic effects of LRINEC were utilized in the systematic review portion of this paper. Further inclusion of 2 × 2 tables and discussion specific to the extremities were applied for citations implemented in the meta-analysis. Of the 111 results, 12 citations (n = 932) were included in this review. The diagnostic sensitivity of the LRINEC score ranged from 36% to 77% while specificity ranged from 72% to 93%. Cumulative odds ratio for LRINEC ≥6 among the 4 studies assessing extremity necrotizing fasciitis was 4.3 with p value of <.05. Sensitivity, specificity, positive predictive value, and negative predictive value was 49.39%, 83.17%, 34.91%, and 89.99%, respectively. Accuracy, the classification by whether a patient was correctly classified, was 77.95%. LRINEC score is effective at distinguishing necrotizing fasciitis from other soft tissue infections however the LRINEC's score greatest clinical application may be its ability to rule out necrotizing fasciitis while its ability to accurately identify the presence of infection remains suboptimal.

Predicting Nonunions in Ankle Fractures Using Quantitative Tibial Hounsfield Samples From Preoperative Computed Tomography: A Multicenter Matched Case Control Study.

The aim of this study is to use tibial Hounsfield unit measurements from preoperative computed tomography scans of ankle fractures to predict delayed union and nonunion. We hypothesize that patients with lower Hounsfield unit averages, an indirect measure of lower bone mineral density, in the distal tibia are more likely to develop delayed union and nonunion complications after ankle fracture surgery. Patient data from January 2010 to January 2020 were retrospectively analyzed from 2 institutions. Exposure cases of delayed union or nonunion that had preoperative computed tomography were compared to 5 controls matched for sex, age, and classification. 3 measurements were taken from the tibia on axial computed tomography and averaged to create a summative measure for overall bone health. Statistical analysis was used to analyze the relationship between the groups. 19 exposure patients were compared to 95 control patients. There were 16 females and 3 males in the exposure group aged from 30 to 88 years. Average follow-up was 1.6 years. The average exposure and control Hounsfield measurements were 186 (161-210) and 258 (248-269), respectively. Significant differences were found for all measured averages. This is the first study to our knowledge relating preoperative tibial Hounsfield measurements to healing rates of ankle fractures. Measurements taken from any of the 3 sites or the average could be an indicator of overall bone health. Using this technique on preoperative imaging will help surgeons adjust their perioperative planning for patients at higher risk for delayed union and nonunion.