Cartilage Restoration for Tibiofemoral Bipolar Lesions Results in Promising Failure Rates: A Systematic Review.

Purpose: The purpose of the present study is to systematically review the available literature for management of bipolar lesions within the tibiofemoral joint and determine whether tibiofemoral cartilage restoration is an effective treatment modality.

Methods: PubMed and MEDLINE databases were queried between 2000 and 2020 using the following keywords: "osteochondral" and "knee" and "microfracture," "autologous chondrocyte implantation (ACI)," or "transplantation." Articles were reviewed for the presence of a bipolar or "kissing" tibiofemoral lesion and reported lesion size, concomitant procedures, failure rates, and time to failure.

Cartilage Restoration of Bipolar Lesions Within the Patellofemoral Joint Delays Need for Arthroplasty: A Systematic Review of Rates of Failure.

Purpose: The purpose of the present review is to systematically review the available literature for failure rates and complications of cartilage restoration of bipolar chondral defects in the patellofemoral (PF) joint to assess the ability to treat these lesions without arthroplasty.

Methods: PubMed and MEDLINE databases were queried between 2000 to 2020 using the keywords "osteochondral" and "knee" and "microfracture," "autologous chondrocyte implantation (ACI)," or "transplantation." Patient selection included patients with bipolar chondral lesions of the patellofemoral joint that were treated with cartilage restoration procedures.

Role of the Hypoxia-Inducible Factor Pathway in Normal and Osteoarthritic Meniscus and in Mice after Destabilization of the Medial Meniscus.

Objective: Meniscus injury and the hypoxia-inducible factor (HIF) pathway are independently linked to osteoarthritis pathogenesis, but the role of the meniscus HIF pathway remains unclear. We sought to identify and evaluate HIF pathway response in normal and osteoarthritic meniscus and to examine the effects of Epas1 (HIF-2α) insufficiency in mice on early osteoarthritis development.

Methods: Normal and osteoarthritic human meniscus specimens were obtained and used for immunohistochemical evaluation and cell culture studies for the HIF pathway.

Effects of tissue culture on the biomechanical properties of porcine meniscus explants.

Background: The meniscus is critical for the normal functioning of the knee joint. The specific aim of this study was to validate an in vitro culture model of meniscus explants for testing the impact of culture conditions on meniscus biomechanical properties. We hypothesized that culturing menisci in the presence of intermediate and high concentration of serum would have a positive effect on the compressive stiffness of the meniscus.

Impact of Clinical Presentation on Imaging Evaluation to Direct Effective Treatment Strategies.

A multitude of musculoskeletal disorders of the knee are commonly encountered in clinical practice. Ensuring an accurate diagnosis can be challenging. It is critical to establish a thoughtful and systematic approach to assessing the patient using history and physical exam followed by appropriate imaging studies.

Variability in Patellofemoral Alignment Measurements on MRI: Influence of Knee Position.

Objective: The purpose of this study was to determine the variability of distances between four distinct anatomic landmarks used for the evaluation of patellofemoral alignment while implementing controlled changes in patient positioning during MRI.

Materials And Methods: Limited MRI was performed of 12 knees in healthy volunteers (10 men, two women; mean age, 28 years) with the knees in four different positions. The four landmarks used were TT (the most anterior point of the osseous tibial tubercle), TG (the nadir of the cartilaginous trochlear groove), PT (the center of the patellar tendon insertion on the tibia), and PCL (the medial border of the posterior cruciate ligament at its insertion along the posterior tibia).

Disease progression and phasic changes in gene expression in a mouse model of osteoarthritis.

Osteoarthritis (OA) is the most common form of arthritis and has multiple risk factors including joint injury. The purpose of this study was to characterize the histologic development of OA in a mouse model where OA is induced by destabilization of the medial meniscus (DMM model) and to identify genes regulated during different stages of the disease, using RNA isolated from the joint "organ" and analyzed using microarrays. Histologic changes seen in OA, including articular cartilage lesions and osteophytes, were present in the medial tibial plateaus of the DMM knees beginning at the earliest (2 week) time point and became progressively more severe by 16 weeks.

Microarray analysis reveals age-related differences in gene expression during the development of osteoarthritis in mice.

Objective: To better understand the contribution of age to the development of osteoarthritis (OA).

Methods: Surgical destabilization of the medial meniscus (DMM) was used to model OA in 12-week-old and 12-month-old male C57BL/6 mice. OA severity was evaluated histologically.

A Comprehensive Histological Assessment of Osteoarthritis Lesions in Mice.

Objective: Accurate histological assessment of osteoarthritis (OA) is critical in studies evaluating the effects of interventions on disease severity. The purpose of the present study was to develop a histological grading scheme that comprehensively and quantitatively assesses changes in multiple tissues that are associated with OA of the stifle joint in mice.

Design: Two representative midcoronal sections from 158 stifle joints, including naturally occurring and surgically induced OA, were stained with H&E and Safranin-O stains.

The female athlete.

Over time, women have become more extensively involved in athletic programs. The female athlete presents a unique challenge to sports medicine in general. Although specific types of injuries are the same as in the male athlete, the female athlete is at higher risk for some of these injuries.

An acellular, allograft-derived meniscus scaffold in an ovine model.

Purpose: The purpose of this study was to develop a meniscus scaffold that has increased porosity and maintains the native meniscus extracellular matrix in an ovine model.

Methods: The medial menisci of skeletally mature ovine (n = 16) were harvested; half were made into meniscus scaffolds (n = 8), and half remained intact (n = 8). Intact and scaffold meniscus tissues were compared by use of histology, DNA content analysis, in vitro cellular biocompatibility assays, and ultrastructural analysis.

Osteochondritis dissecans of the humeral head.

Osteochondritis dissecans (OCD), although common in other regions, is exceptional in the shoulder. We present a rare case of OCD of the humeral head in a young patient that remained undiagnosed for a 3-year period.

Freeze-dried allografts for anterior cruciate ligament reconstruction.

Freeze-dried allografts represent a viable and functional alternative to fresh-frozen allograft and autograft constructs. Compared with fresh-frozen allograft constructs, freeze-dried soft tissue allograft constructs have many advantages including limited immunogenicity, ease of graft storage, comparable mechanical properties of soft tissue constructs, and the potential for improved biologic incorporation. This article reviews the fundamental processing of freeze-dried allografts and summarizes the clinical and basic science studies supporting the safe and effective use of freeze-dried allograft constructs for anterior cruciate ligament reconstruction.

Surgical treatment of chronic posteromedial instability using capsular procedures.

Patients with posteromedial corner injuries of the knee present a significant problem to the clinician. Often the symptoms of anteromedial rotatory instability may be overlooked due to concurrent anterior cruciate ligament and/or posterior cruciate ligament injuries. When addressing concurrent ligamentous injuries to the knee, the clinician may fail to isolate anteromedial rotatory instability on physical examination and imaging studies may not specifically identify damage to posteromedial corner structures.

Future treatment of osteoarthritis.

Osteoarthritis represents an advanced stage of disease progression caused in part by injury, loss of cartilage structure and function, and an imbalance in inflammatory and noninflammatory pathways. The burden of this disease will increase in direct proportion to the increase in the older adult population. Research on current and experimental treatment protocols are reviewed, including the effect of hyaluronic acid in both in vitro and in vivo studies, autologous chondrocyte and osteochondral plug implantation, and gene therapy.

Transforming growth factor-beta1 induced alteration of skeletal morphogenesis in vivo.

Transforming growth factor beta (TGF-beta) is expressed in the growth plate and is an important regulator of chondrocyte maturation. Loss of function results in premature chondrocyte maturation both in vitro and in vivo. While TGF-beta inhibits chondrocyte maturation in cell cultures, the effect of increased TGF-beta has not been well characterized in an in vivo development model.

A role for the BMP antagonist chordin in endochondral ossification.

Bone morphogenetic proteins (BMPs) are ubiquitous regulators of cellular growth and differentiation. A variety of processes modulate BMP activity, including negative regulation by several distinct binding proteins. One such BMP antagonist chordin has a role in axis determination and neural induction in the early embryo.