A Novel Method Facilitating the Simple and Low-Cost Preparation of Human Osteochondral Slice Explants for Large-Scale Native Tissue Analysis.

For in vitro modeling of human joints, osteochondral explants represent an acceptable compromise between conventional cell culture and animal models. However, the scarcity of native human joint tissue poses a challenge for experiments requiring high numbers of samples and makes the method rather unsuitable for toxicity analyses and dosing studies. To scale their application, we developed a novel method that allows the preparation of up to 100 explant cultures from a single human sample with a simple setup. Explants were cultured for 21 days, stimulated with TNF-α or TGF-ß3, and analyzed for cell viability, gene expression and histological changes. Tissue cell viability remained stable at >90% for three weeks. Proteoglycan levels and gene expression of COL2A1, ACAN and COMP were maintained for 14 days before decreasing. TNF-α and TGF-ß3 caused dose-dependent changes in cartilage marker gene expression as early as 7 days. Histologically, cultures under TNF-α stimulation showed a 32% reduction in proteoglycans, detachment of collagen fibers and cell swelling after 7 days. In conclusion, thin osteochondral slice cultures behaved analogously to conventional punch explants despite cell stress exerted during fabrication. In pharmacological testing, both the shorter diffusion distance and the lack of need for serum in the culture suggest a positive effect on sensitivity. The ease of fabrication and the scalability of the sample number make this manufacturing method a promising platform for large-scale preclinical testing in joint research.

Open Versus Arthroscopic Mosaicplasty of the Knee: A Cadaveric Assessment of Accuracy of Graft Placement Using Navigation.

PURPOSE: The purpose of this study was to compare an open freehand mosaicplasty technique with an arthroscopic technique for the treatment of osteochondral lesions by measuring the instrument deviation, quantifying this deviation, and providing numerical information on the difference in the outcomes of these techniques. METHODS: Four cadaveric knees were used. Reference markers were attached to the femur, tibia, and donor/recipient site guides. A total of 10 osteochondral grafts were harvested and inserted into recipient sites arthroscopically and 10 similar grafts were inserted freehand. The angles of graft removal and placement were calculated for each of the surgical groups compared. Ostensibly, a navigation system was used as an aid, to measure the graft placement parameters. RESULTS: Statistical analysis revealed that there was no statistically significant difference between the arthroscopic method and the freehand method regarding the angle of graft removal at the donor site (P = .162), recipient site plug removal angle (P = .731), and recipient site graft placement angle (P = .630). In the freehand group, the mean angle of graft removal at the donor site was 12°, the mean angle of recipient site plug removal was 10.7°, and the mean angle of recipient site plug placement was 10.6°. Using the arthroscopic technique, the mean angle of graft removal at the donor site was 17.14°, the mean angle of recipient site plug removal was 12.0°, and the mean angle of recipient site graft placement was 10.14°. CONCLUSIONS: Our study revealed there was no statistically significant difference regarding precision and accuracy during harvesting, recipient site preparation, and plug placement between the 2 techniques. CLINICAL RELEVANCE: Controversy exists whether an open or arthroscopic osteoarticular transfer system (OATS) technique provides superior accuracy. According to our results, there is no statistically significant difference regarding better visualization, precision, and accuracy between the freehand and arthroscopic techniques. However, larger number of specimens are required for study.

Peri-prosthetic hip infections: in favour of one-stage.

Although it does offer certain obvious advantages, the one-staged revision approach in infected THA remains rare in the field of orthopaedics. Besides the reduced number of surgical interventions for patients, it is associated with a decreased inpatient hospital stay and quicker mobilisation. Furthermore, it might be the more cost-effective approach and enables a reduced duration of post-operative systemic antibiotics, usually less than 14 days in our setting. Technically speaking, the presence of a positive culture of a pre-operative aspiration and respective antibiogram are mandatory requirements. A general cemented implant fixation using topical antibiotics is the treatment of choice for single-staged procedures. The key to surgical success is based on the well-defined and detailed intra-hospital infrastructure, including a meticulous pre-operative hip aspiration regime, pre-operative planning and an aggressive intra-operative surgical approach.

Critical review of the current practice for computer-assisted navigation in total knee replacement surgery: cost-effectiveness and clinical outcome.

In this article, we present a review of the current practice regarding computer-assisted navigation in total knee replacement together with the bearing on cost-effectiveness and clinical outcome.

Comparative study of different intraoperative 3-D image intensifiers in orthopedic trauma care.

INTRODUCTION: Recently, isocentric C-arm fluoroscopy (Iso-C 3D) has been introduced as a precise imaging modality for intraoperative evaluation and management of fractures and osteosyntheses. The Siemens Iso-C 3D collects multiple fluoroscopic images during a 190-degree arc of rotation around the anatomic region of interest and reconstructs them into sagittal, axial, and coronal planes. Like the Iso-C 3D, the new Ziehm Vario 3D imaging system reconstructs images in multiple planes, but only requires a 136-degree arc of rotation. The purpose of this study was to compare the image quality and range of applicability of these two imaging systems. METHODS: All the tests were performed on a human cadaver. In the first part of the experiment, different bones and joints were scanned in their native condition using both the Iso-C 3D and Vario 3D. In the second part of the experiment, scans were performed in the same anatomic regions after simulated fractures and subsequent fixation. In some cases, suboptimal placement of hardware was intentionally undertaken. Direct visualization of the fracture construct and in certain cases computed tomographic (CT) imaging served as the gold standard. The scans from both imaging systems were analyzed using a DICOM viewer by five orthopedic trauma surgeons randomized and blinded to the study. The evaluation was based on the overall image quality, delineation of cancellous and cortical bone, delineation of joint surfaces, presence of artifacts, visualization quality of intra-articular incongruities, quality of reduction and implant positioning, and clinical applicability of the scan. These items were rated using a visual analog scale and a points system. A total of 55 3D scans were made and evaluated. RESULTS: There was no significant difference between the two imaging systems in terms of the overall image quality, delineation of cancellous and cortical bone, and the presence of artifacts. The delineation of joint surfaces was significantly better visualized with the Iso-C 3D. Furthermore, Iso-C 3D scans demonstrated a higher overall clinical applicability than Vario 3D images. However, the Vario 3D was able to provide superior quality with scans of the shoulder joint and the adipose tissue. There was no significant difference in the visualization of intra-articular incongruities, quality of reduction, and implant positioning. CONCLUSION: Although the Iso-C 3D imaging system was superior in delineating the joint surfaces, the image quality, and the overall clinical applicability, the study revealed that both devices provided 3D images with sufficient quality to the surgeon to assess clinically relevant questions, including the quality of fracture reduction and implant positioning. On the other hand, the Ziehm Vario 3D is capable of doing scans of the shoulder area, which could not be taken with the Siemens Iso-C 3D because of the isocentric design.

Ligament tension in the ACL-deficient knee: assessment of medial and lateral gaps.

Obtaining symmetric and balanced gaps under equilateral loads is a common goal in posterior cruciate ligament (PCL)-retaining and -sacrificing TKAs. Owing to limitations in existing surgical tensors, however, tensing knee ligaments with standardized and symmetric loads has been possible only with the patella subluxated or everted. We therefore determined the influences of (1) patellar eversion versus complete reduction, (2) PCL resection, and (3) load magnitude on gap symmetry and balance in the anterior cruciate ligament (ACL)-deficient knee. We used a novel computer-controlled tensioner to measure gaps in 10 cadavers with an applied force of 50 N, 75 N, and 100 N per side. Gap data were acquired at 0 masculine, 30 masculine, 60 masculine, 90 masculine, and 120 masculine flexion with the patella reduced and everted and with the PCL intact and resected. Everting the patella tightened the medial and lateral flexion gaps between 90 masculine and 120 masculine by 0.7 mm to 2.7 mm. PCL resection increased gaps from 30 degrees to 120 degrees by 1 mm to 3 mm. Increasing the force from 50 N to 100 N increased the mean gap by 0.5 mm. Everting the patella and resecting the PCL influenced gap balance and symmetry. Surgeons should be aware of how these conditions affect gaps during assessment and balancing.

The accuracy and precision of computer assisted surgery in the assessment of frontal plane deviations of the lower extremity: a femoral fracture model.

OBJECTIVES: Mechanical axis deviation of the lower extremity as a result of malreduction or malunion of fractures plays an important role in the development of arthritis. Therefore it is crucial to restore the limb alignment as accurate as possible. The purpose of this study was to evaluate the accuracy and precision of navigation in assessing isolated frontal plane (varus/valgus) deviations of the lower limb in a simulated fracture model of the femur. MATERIALS AND METHODS: Three fracture models with ten specimens in each were created in femoral synthetic composite bones to simulate a subtrochanteric (AO/OTA 31-A1), mid-diaphyseal (AO/OTA 32-A3), and supracondylar (AO/OTA 33-A1) femur fracture. Each specimen was mounted on a custom holding device and registered with the navigation system. Eight custom-made aluminum wedges of varying angles (5 degrees -26 degrees ) were used to create varus/valgus angulations at the fracture site. After wedge placement, the frontal plane deformity was recorded and registered by the navigation system. The means and standard deviations for each navigated wedge angle were calculated and compared to the actual wedge angle using a one sample t test. A single factor ANOVA test was subsequently performed to see if the differences between the navigated mean angles in each fracture group were statistically significant. The level of significance was defined as P < 0.05. RESULTS: None of the navigated mean angles were found to be significantly different from the actual wedge angles (P = 0.05-1.00). More specifically, the differences between the navigated mean angles and the actual wedge angles ranged from 0 degrees to 0.7 degrees . Furthermore, the differences between the navigated mean angles in each angle group were found to be statistically insignificant (P = 0.53-0.99). CONCLUSION: The high accuracy and precision of navigation systems in determining frontal plane deformities of long bones can make them an invaluable tool for the exact reduction and realignment of lower extremity fractures.