Rotating hinge knee causes lower bone-implant interface stress compared to constrained condylar knee replacement.

Purpose: To compare the stresses at bone-arthroplasty interface of constrained and semi-constrained knee prostheses, using the finite element (FE) method as a predictor of the survivorship of the implants.

Methods: Three-dimensional FE models of the knee implanted with rotating hinge (RHK) and legacy constrained condylar (LCCK) prostheses were generated to study the loads and stresses for two situations: medial- and lateral collateral ligament deficiencies in full extension.

Results: On average, the shear stress developed at bone-implant interface dropped from 16.

One Dose of Intravenous Tranexamic Acid Is Equivalent to Two Doses in Total Hip and Knee Arthroplasty.

Background: Tranexamic acid (TXA) helps to prevent excessive blood loss during total hip arthroplasty (THA) and total knee arthroplasty (TKA), but the most efficacious dosing protocol has not been ascertained. The purpose of this study was to identify whether 1 dose of intravenous TXA is equivalent to 2 doses for reducing blood loss and transfusion rates following THA and TKA without an increase in complications.

Methods: We identified 1,736 patients who underwent THA (592 who did not receive TXA, 454 who received 1 dose of TXA, and 690 who received 2 doses) and 2,042 patients who underwent TKA (744 who did not receive TXA, 499 who received 1 dose, and 799 who received 2 doses) from 2012 to 2016.

Platelet-derived growth factor-coated decellularized meniscus scaffold for integrative healing of meniscus tears.

Unlabelled: The aim of this study was to examine the potential of platelet-derived growth factor (PDGF)-coated decellularized meniscus scaffold in mediating integrative healing of meniscus tears by inducing endogenous cell migration. Fresh bovine meniscus was chemically decellularized and covalently conjugated with heparin and PDGF-BB. In vitro PDGF release kinetics was measured.

Does Anterior Cruciate Ligament Reconstruction Affect the Outcome of Osteochondral Allograft Transplantation? A Matched Cohort Study With a Mean Follow-up of 6 Years.

Background: Few studies have evaluated the influence of anterior cruciate ligament (ACL) reconstruction on the outcome of cartilage repair. Hypothesis/Purpose: The purpose was to investigate the association between ACL reconstruction and functional outcomes after osteochondral allograft (OCA) transplantation. The hypothesis was that patients treated with OCA transplantation who had a history of ACL reconstruction would have inferior clinical outcomes and lower osteochondral graft survivorship when compared with a matched group of patients undergoing OCA transplantation without a history of ACL reconstruction.

In Vitro and In Vivo Performance of Tissue-Engineered Tendons for Anterior Cruciate Ligament Reconstruction.

Background: Anterior cruciate ligament (ACL) reconstruction is the current standard of care for ACL tears. However, the results are not consistently successful; autografts or allografts have certain disadvantages; and synthetic grafts have had poor clinical results.

Purpose: To determine if recellularization of decellularized tendons combined with mechanical stimulation in a bioreactor could replicate the mechanical properties of the native ACL and be successfully used for ACL reconstruction in vivo.

Second-Generation Electronic Ligament Balancing for Knee Arthroplasty: A Cadaver Study.

Background: Knee instability is emerging as a major complication after total knee arthroplasty (TKA), with ligament laxity and component alignment listed as important contributory factors. Knee balancing remains an art and is largely dependent on the surgeon's subjective "feel." The objectives were to measure the accuracy of an electronic balancing device to document the magnitude of correction in knee balance after soft-tissue releases and measure change in knee laxity after medial release.

Gene expression profiles of the meniscus avascular phenotype: A guide for meniscus tissue engineering.

Avascular (Avas) meniscus regeneration remains a challenge, which is partly a consequence of our limited knowledge of the cells that maintain this tissue region. In this study, we utilized microarrays to characterize gene expression profiles of intact human Avas meniscus tissue and of cells following culture expansion. Using these data, we examined various 3D culture conditions to redifferentiate Avas cells toward the tissue phenotype.

Long-term Follow-up of Revision Osteochondral Allograft Transplantation of the Ankle.

Background: Osteochondral allograft (OCA) transplantation is a useful alternative for treatment of posttraumatic ankle arthritis in young patients but has a relatively high failure rate and further procedures are often required. The purpose of this study was to evaluate outcomes of patients who underwent revision OCA transplantation of the ankle after failed primary OCA transplantation.

Methods: Twenty patients underwent revision OCA transplantation of the ankle between 1988 and 2015.

Fresh Osteochondral Allograft Transplantation for Spontaneous Osteonecrosis of the Knee: A Case Series.

Background: Spontaneous osteonecrosis of the knee (SONK) is a clinical entity identified by acute knee pain usually associated with joint effusion, with radiographic findings of a radiolucent defect on the weightbearing area of the femoral condyle. Conservative treatment is initially undertaken; however, surgical procedures are often necessary. Historically, surgical options have included core decompression, cartilage repair, high tibial osteotomy, or joint arthroplasty.

Meniscal Tissue Engineering Using Aligned Collagen Fibrous Scaffolds: Comparison of Different Human Cell Sources.

Hydrogel and electrospun scaffold materials support cell attachment and neotissue development and can be tuned to structurally and mechanically resemble native extracellular matrix by altering either electrospun fiber or hydrogel properties. In this study, we examined meniscus tissue generation from different human cell sources including meniscus cells derived from vascular and avascular regions, human bone marrow-derived mesenchymal stem cells, synovial cells, and cells from the infrapatellar fat pad (IPFP). All cells were seeded onto aligned electrospun collagen type I scaffolds and were optionally encapsulated in a tricomponent hydrogel.

Fresh Osteochondral Allograft Transplantation for Fractures of the Knee.

Objective The purpose of this study was to evaluate functional outcomes and allograft survivorship among patients with knee fracture who underwent fresh osteochondral allograft (OCA) transplantation as a salvage treatment option. Design Retrospective analysis of prospectively collected data. Setting Department of Orthopaedic Surgery at one hospital.

Relevance of meniscal cell regional phenotype to tissue engineering.

Purpose: Meniscus contains heterogeneous populations of cells that have not been fully characterized. Cell phenotype is often lost during culture; however, culture expansion is typically required for tissue engineering. We examined and compared cell-surface molecule expression levels on human meniscus cells from the vascular and avascular regions and articular chondrocytes while documenting changes during culture-induced dedifferentiation.

Repair of Avascular Meniscus Tears with Electrospun Collagen Scaffolds Seeded with Human Cells.

The self-healing capacity of an injured meniscus is limited to the vascularized regions and is especially challenging in the inner avascular regions. As such, we investigated the use of human meniscus cell-seeded electrospun (ES) collagen type I scaffolds to produce meniscal tissue and explored whether these cell-seeded scaffolds can be implanted to repair defects created in meniscal avascular tissue explants. Human meniscal cells (derived from vascular and avascular meniscal tissue) were seeded on ES scaffolds and cultured.

Control of Retinal Ganglion Cell Positioning and Neurite Growth: Combining 3D Printing with Radial Electrospun Scaffolds.

Retinal ganglion cells (RGCs) are responsible for the transfer of signals from the retina to the brain. As part of the central nervous system, RGCs are unable to regenerate following injury, and implanted cells have limited capacity to orient and integrate in vivo. During development, secreted guidance molecules along with signals from extracellular matrix and the vasculature guide cell positioning, for example, around the fovea, and axon outgrowth; however, these changes are temporally regulated and are not the same in the adult.

Osteochondral Allograft Transplantation of the Femoral Trochlea.

Background: Osteochondral allograft (OCA) transplantation is a recognized treatment modality for cartilage damage in the knee. Few reports are available on outcomes of OCA in the patellofemoral joint, and there are no reports on lesions isolated to the femoral trochlea.

Purpose: To evaluate graft survivorship and clinical outcomes in patients who had an OCA to the femoral trochlea.

Histopathological analyses of murine menisci: implications for joint aging and osteoarthritis.

Objective: To establish a standardized protocol for histopathological assessment of murine menisci that can be applied to evaluate transgenic, knock-out/in, and surgically induced OA models.

Methods: Knee joints from C57BL/6J mice (6-36 months) as well as from mice with surgically-induced OA were processed and cut into sagittal sections. All sections included the anterior and posterior horns of the menisci and were graded for (1) surface integrity, (2) cellularity, (3) Safranin-O staining distribution and intensity.

Outcomes of anatomic shoulder arthroplasty in primary osteoarthritis in type B glenoids.

Background: Primary glenohumeral osteoarthritis with posterior wear of the glenoid and posterior subluxation of the humerus (Walch type B) presents a challenge to the treating surgeon. Our hypothesis was that glenoids with biconcavity (B2) would be associated with worse outcomes (functional scores and complications) than B1 glenoids.

Materials And Methods: We retrospectively analyzed prospectively collected data on 112 anatomic total shoulder arthroplasties (104 patients) with B glenoids.

Osteochondral Allograft Transplantation for Knee Lesions after Failure of Cartilage Repair Surgery.

Objective: The objective of this study was to assess the outcome of osteochondral allograft (OCA) transplantation as a salvage procedure after various cartilage repair surgeries.

Design: One hundred sixty-four knees in 163 patients (mean age = 32.6 years; range = 11-59 years; 55% males) were treated with OCA transplantation after subchondral marrow stimulation (SMS), osteochondral autograft transplantation (OAT), and autologous chondrocyte implantation (ACI).

Fresh osteochondral allografts in the knee: comparison of primary transplantation versus transplantation after failure of previous subchondral marrow stimulation.

Background: In most treatment algorithms, osteochondral allograft (OCA) transplantation is regarded as an alternative salvage procedure when other, previous reparative treatments have failed.

Purpose: To compare the outcomes of a retrospective matched-pair cohort of (1) primary OCA transplantation and (2) OCA transplantation after failure of previous subchondral marrow stimulation.

Study Design: Cohort study; Level of evidence, 3.

Patient-specific computer model of dynamic squatting after total knee arthroplasty.

Knee forces are highly relevant to performance after total knee arthroplasty especially during high flexion activities such as squatting. We constructed subject-specific models of two patients implanted with instrumented knee prostheses that measured knee forces in vivo. In vivo peak forces ranged from 2.

Effect of microseparation and third-body particles on dual-mobility crosslinked hip liner wear.

Large heads have been recommended to reduce the risk of dislocation after total hip arthroplasty. One of the issues with larger heads is the risk of increased wear and damage in thin polyethylene liners. Dual-mobility liners have been proposed as an alternative to large heads.

Comparative biomechanical analysis of human and caprine knee articular cartilage.

Background: The goat is one of the most commonly used preclinical models for focal defect repair and regeneration. While the biomechanics of the human knee has been studied extensively, less is known about the biomechanics of the caprine knee. Differences between human and caprine knees have not been quantified and their significance is largely unknown.