Tibial subchondral trabecular bone micromechanical and microarchitectural properties are affected by alignment and osteoarthritis stage.

At advanced knee osteoarthritis (OA) stages subchondral trabecular bone (STB) is altered. Lower limb alignment plays a role in OA progression and modify the macroscopic loading of the medial and lateral condyles of the tibial plateau. How the properties of the STB relate to alignment and OA stage is not well defined. OA stage (KL scores 2-4) and alignment (HKA from 17° Varus to 8° Valgus) of 30 patients were measured and their tibial plateau were collected after total knee arthroplasty. STB tissue elastic modulus, bone volume fraction (BV/TV) and trabecula thickness (Tb.Th) were evaluated with nanoindentation and µCT scans (8.1 µm voxel-size) of medial and lateral samples of each plateau. HKA and KL scores were statistically significantly associated with STB elastic modulus, BV/TV and Tb.Th. Medial to lateral BV/TV ratio correlated with HKA angle (R = -0.53, p = 0.016), revealing a higher ratio for varus than valgus subjects. STB properties showed lower values for KL stage 4 patients. Tissue elastic modulus ratios and BV.TV ratios were strongly correlated (R = 0.81, p < 0.001). Results showed that both micromechanical and microarchitectural properties of STB are affected by macroscopic loading at late stage knee OA. For the first time, a strong association between tissue stiffness and quantity of OA STB was demonstrated.

Identification of the retrotalar pulley of the Flexor Hallucis Longus tendon.

Functional Hallux Limitus is the expression of the gliding restraint of the Flexor Hallucis Longus (Fhl) tendon, resulting in several painful syndromes. This impingement is located along the tract of the Fhl tendon at the level of its retrotalar tunnel sealed posteriorly by a fibrous pulley. This pulley, although poorly anatomically characterized, has been arthroscopically proven that its presence or resection plays a pivotal clinical role in the biomechanics of the lower leg, being the main restraint to the physiological movement of the Fhl tendon. The aim of our study was to identify and characterize this anatomical structure. Eleven cadaveric lower legs were initially assessed by computer tomography (CT) imaging, subsequently plastinated, dissected and histologically evaluated by use of Mayer's and Hematoxylin stain. We have shown that the retrotalar pulley of the Fhl shares the same histological characteristics with the retinaculum of the long fibularis muscle and the retinaculum of flexor digitorum muscle, thus it constitutes a different entity than the adjacent formations.

Upper Femur Anatomy Depends on Age and Gender: A Three-Dimensional Computed Tomography Comparative Bone Morphometric Analysis of 628 Healthy Patients' Hips.

BACKGROUND: The knowledge of proximal femur geometry is essential in the understanding and treatment of hip pathologies. Our aim is to evaluate the range of "normal anatomical values of the proximal femur" and their relationship to age, gender, and ethnicity in a cohort of healthy population, using a 3-dimensional computed tomography automated software. METHODS: The pelvis and bilateral femora of 628 healthy individuals (394 males/234 females, mean age 61.5 ± 16.5 years, mean body mass index [BMI] 26.9 ± 5.2 kg/m2) including 2 ethnicities (226 Asians and 406 Caucasians) were assessed with a 3-dimensional computed tomography scan-based system using algorithm-calculated landmarks. The demographic parameters recorded were age, gender, BMI, and ethnicity. The femoral neck-shaft angle (NSA), femoral neck version, femoral offset (FO), and femoral canal flare index (fCFI) were calculated for each individual. Analyses were performed using SPSS version 22. P-values <.05 were considered to indicate statistical significance. RESULTS: Overall, the mean NSA was 124.7° (standard deviation [SD] 6.2), mean femoral neck version was 14.5° (SD 8.1), mean FO was 42.9 mm (SD 6.8), and mean fCFI was 3.4 (SD 0.5). Gender was associated with all parameters, with the females presenting more valgus and anteverted hips. Multivariate analysis revealed a lower NSA and fCFI and a higher FO for older individuals. Ethnicity and BMI were not associated with any parameters. CONCLUSION: Our results showed that there is a direct relationship of age and gender to the variations in the investigated proximal femur anatomical parameters in a large cohort of healthy individuals. Those important gender-based and age-based differences might advocate for more varus and lateralized component to reproduce preoperative anatomy of male and patients older than 50 years.

Systemic inflammatory response after extremity or truncal fracture operations.

BACKGROUND: The purpose of this study was to assess proinflammatory markers in blunt trauma patients regarding the relationship of these and blood loss and duration of surgery in different fracture locations. DESIGN: Prospective, multicenter, nonrandomized cohort study. SETTING: Three level I trauma centers. PATIENTS: Sixty-eight blunt trauma patients, who did not require emergency operations and had sustained truncal or extremity fractures, were included. In two index patient groups, patients with spinal fractures (group SF, n = 24) and pelvic and acetabular fractures (group PAF, n = 21) underwent fixation of their fractures and were compared with a group of patients with isolated fractures (group FF, n = 28). Ten healthy volunteers served as controls. INTERVENTION: Internal fixation of pelvic, acetabular and spinal fractures, intramedullary nailing of femoral fractures, measurement of proinflammatory cytokines. MAIN OUTCOME MEASURES: From serially sampled central venous blood, the perioperative concentrations of interleukin-6 (IL-6) and IL-8 were evaluated during a 24-hour period and set into relation with the duration of surgery and the degree of blood loss. RESULTS: Intramedullary instrumentation for isolated PAF caused a significant perioperative increase in the concentrations of IL-6 (preoperative: 16 pg/mL +/- 12 pg/mL, 7 hours: 89 pg/mL +/- 15 pg/mL, and 24 hours: 107 pg/mL +/- 27 pg/mL, p < 0.05). This increase was comparable with the isolated femoral fracture (group FF: IL-6 preoperative, 52 pg/mL +/- 12 pg/mL; 7 hours, 78 pg/mL +/- 14 pg/mL; and 24 hours, 120 pg/mL +/- 23 pg/mL, p = 0.02). The changes observed after spinal fracture fixations (group SF) were considerably lower (IL-6 preoperative: 11 pg/mL +/- 6 pg/mL, 7 hours: 16 pg/mL +/- 11 pg/mL, and 24 hours: 56 pg/mL +/- 19 pg/mL). The percent change of baseline IL-6 and IL-8 concentrations, and the blood loss in group PAF at 24 hours were positively correlated (IL-6 r = 0.72, p < 0.03, IL-8 0.67, p = 004) after insertion. No correlation with the duration of surgery was found. CONCLUSIONS: The release of proinflammatory cytokines was higher in patients when their pelvic fractures were operated than in patients with spine fracture fixations, and was associated with the degree of blood loss. A higher increase in cytokine levels occurred when they were performed early (day 1-2) across all patient groups. The level of the released markers seems to be related to the magnitude of surgery, rather than to the duration of the procedure. This study supports the value of immunologic markers in determining subclinical changes during and after orthopedic surgical procedures.