Objective Supply-demand mismatch of medial femoral condyle (MFC) osteochondral allografts (OCAs) remains a rate-limiting factor in the treatment of osteochondral defects of the femoral condyle. Surface contour mapping was used to determine whether a contralateral lateral femoral condyle (LFC) versus ipsilateral MFC OCA differs in the alignment of donor:native subchondral bone for large osteochondral defects of the MFC. Design Thirty fresh-frozen human femoral condyles were matched by tibial width into 10 groups of 3 condyles (MFC recipient, MFC donor, and LFC donor) each for 3 cartilage surgeons (90 condyles). The recipient MFC was imaged using nano-computed tomography scan. Donor oval grafts were harvested from each matched condyle and transplanted into a 17 mm × 36 mm defect created in the recipient condyle. Following the first transplant, the recipient condyle was imaged and superimposed on the native condyle nano-CT scan. The donor plug was removed and the process repeated for the other donor. Surface height deviation and circumferential step-off height deviation were compared between native and donor subchondral bone surfaces for each transplant. Results There was no statistically significant difference in mean subchondral bone surface deviation (LFC = 0.87 mm, MFC = 0.76 mm, P = 0.07) nor circumferential step-off height (LFC = 0.93 mm, MFC = 0.85 mm, P = 0.09) between the LFC and MFC plugs. There were no significant differences in outcomes between surgeons. Conclusions There were no significant differences in subchondral bone circumferential step-off or surface deviation between ipsilateral MFC and contralateral LFC oval-shaped OCAs for 17 mm × 36 mm defects of the MFC.

The most common means of sternal closure after sternotomy is stainless steel wire cerclage. These wires, while inexpensive and simple in design, are known to be associated with low strength and sternal dehiscence. In this biomechanical analysis, we compare single sternal wires, double sternal wires, and a novel sternal closure device we have designed to mitigate sternal dehiscence. The device uses polymer grommets at the sternal interfaces to distribute load over a large surface area of bone. Samples of each closure device were installed in a bone model and distracted at a rate of 10 mm/min while tensile forces were continuously measured and compared. Single wires generated the lowest stiffness and strength values, followed by the double wires. The novel device demonstrated significantly higher stiffness and strength at all displacements compared with the single and double wires. Clinical use of this device may result in meaningful reduction in complications associated with the use of standard sternal wires such as sternal separation and fracture.

Osteoporosis is a major public health threat with significant physical, psychosocial, and financial consequences. The calcaneus bone has been used as a measurement site for risk prediction of osteoporosis by noninvasive quantitative ultrasound (QUS). By adding optical contrast to QUS, our previous studies indicate that a combination of photoacoustic (PA) and QUS, that is, PAQUS, provides a novel opportunity to assess the health of human calcaneus. Calibration of the PAQUS system is crucial to realize quantitative and repeatable measurements of the calcaneus. Therefore, a phantom which simulates the optical, ultrasound, and architectural properties of the human calcaneus, for PAQUS system calibration, is required. Additionally, a controllable phantom offers researchers a versatile framework for developing versatile structures, allowing more controlled assessment of how varying bone structures cause defined alterations in PA and QUS signals. In this work, we present the first semi-anthropomorphic calcaneus phantom for PAQUS. The phantom was developed based on nano computed-tomography (nano-CT) and stereolithography 3D printing, aiming to maximize accuracy in the approximation of both trabecular and cortical bone microstructures. Compared with the original digital input calcaneus model from a human cadaveric donor, the printed model achieved accuracies of 71.15% in total structure and 87.21% in bone volume fraction. Inorganic materials including synthetic blood, mineral oil, intralipid, and agar gel were used to model the substitutes of bone marrow and soft tissue, filling and covering the calcaneus phantom. The ultrasound and optical properties of this phantom were measured, and the results were consistent with those measured by a commercialized device and from previous in vivo studies. In addition, a short-term stability test was conducted for this phantom, demonstrating that the optical and ultrasound properties of the phantom were stable without significant variation over 1 month. This semi-anthropomorphic calcaneus phantom shows structural, ultrasound, and optical properties similar to those from a human calcaneus in vivo and, thereby, can serve as an effective source for equipment calibration and the comprehensive study of human patients.

BackgroundPatients discharged to non-home facilities (NHD) after total hip arthroplasty (THA) and total knee (TKA) arthroplasty experience higher rates of adverse events and may require more aggressive venous thromboembolism (VTE) chemoprophylaxis. Our aim was to compare the rates of VTE in NHD patients and those discharged home (HD) after THA/TKA. Our secondary aim was to determine VTE rates within HD and NHD groups when stratified by chemoprophylactic regimen.MethodsA retrospective cohort of primary THA and TKA patients were stratified into HD and NHD, then allocated into groups by chemoprophylactic regimen on discharge: aspirin alone (AA), more aggressive (MA) chemoprophylaxis, and other regimens (other). The primary outcome was VTE. Rates of VTE in HD and NHD patients, as well as AA and MA regimens, were analyzed using a generalized linear regression model.ResultsSix thousand three hundred seventy-nine patients were included with 1.03% experiencing VTE. HD had lower rates of VTE compared to NHD (0.83% vs 2.17%, P < .001). AA had similar rates of VTE compared to MA (0.99% vs 1.08%, P = .82). NHD patients had a lower VTE rate with MA vs AA prophylaxis (1.47% vs 3.83%, P = .016). HD patients treated with AA vs MA had no difference in VTE rates (0.76% vs 0.96%, P = .761).ConclusionsNHD patients have higher rates of VTE than HD patients. However, NHD patients have significantly lower rates of VTE on MA chemoprophylaxis compared to those on AA. Providers should consider prescribing MA VTE chemoprophylaxis for NHD patients. Prospective, randomized studies are necessary to confirm these recommendations.

Background: The goal of this study was to use nano-computed tomography to describe the intraosseous vascularity and structural characteristics of commonly used distal radius vascularized bone grafts for treatment of scaphoid nonunion. Methods: We obtained 8 fresh frozen human cadaver forearm specimens for infusion of barium contrast. Specimens were scanned and segmented to quantify the vascular volume and trabecular density within 3 common graft regions, including 1, 2 intercompartmental supraretinacular artery (1,2 ICSRA), fourth extensor compartment artery (4 ECA), and volar carpal artery (VCA), as well as thirds of the scaphoid. Outcomes also included mean and maximum cortical thickness and number of cortical perforators. Single-specimen analyses were also performed comparing vascularity and trabecular density of each graft with scaphoid regions of a single specimen. Statistical analysis was performed using analysis of variance with post hoc Tukey testing when P value was less than .05. Results: There was no significant difference between groups in the mean percent vascularity ( P = .76). The ratio of trabecular bone in each graft to scaphoid thirds was less than 1. The mean cortical thickness (0.79 mm, 95% confidence interval [CI], 0.66-0.93 mm) and maximum cortical thickness (1.45 mm, 95% CI, 1.27-1.63 mm) of VCA grafts were both significantly greater than those of 4 ECA and 1,2 ICSRA ( P < .001). Conclusions: There were no differences between vascular density of the 3 grafts and the scaphoid. Pedicled distal radius bone grafts have similar vascularity but morphometric differences such as cortical thickness and trabecular density which have unclear clinical implications.

The long-term objective of the program is to develop a highly innovative platform to measure the health of human calcaneus in vivo by using our recently invented photoacoustic techniques. To better calibrate the platform and investigate the bone properties, a phantom which simulates the optical, ultrasound and architectural properties of human calcaneus is required. In this work, a semi-anthropomorphic photoacoustic calcaneus phantom is developed based on micro-CT and SLA 3D printing techniques. The measured microarchitectural, optical and ultrasound properties of the phantom are all consistent with those in human calcaneus in vivo.