Clinical cartilage restoration is evolving, with established and emerging technologies. Randomized, prospective studies with adequate power comparing the myriad of surgical techniques used to treat chondral injuries are still lacking and it remains a challenge for the surgeon treating patients to make evidence-based decisions.
Full-thickness chondral defects and early osteoarthritis continue to present major challenges for the patient and the orthopaedic surgeon as a result of the limited healing potential of articular cartilage. The use of bioactive growth factors is under consideration as a potential therapy to enhance healing of chondral injuries and modify the arthritic disease process.
The best strategy for delivering growth factors to cells for the purpose of cartilage tissue engineering remains an unmet challenge. Tethering biotinylated insulin-like growth factor-1 (bIGF-1) to the self-assembling peptide scaffold (RADA)effectively delivers bioactive bIGF-1 to cardiac tissue.
Photopolymerizable poly(ethylene glycol) (PEG) hydrogels offer a platform to deliver cells in vivo and support three-dimensional cell culture but should be designed to degrade in sync with neotissue development and endure the physiologic environment.
Soluble factors released from chondrocytes can both enhance and induce chondrocyte-like behavior in cocultured dedifferentiated cells. The ability to similarly prime and modulate biosynthetic activity of differentiated cells encapsulated in a three-dimensional environment is unknown.
Cartilage Matrix Formation by Bovine Mesenchymal Stem Cells in Three-dimensional Culture Is Age-dependent
Cartilage degeneration is common in the aged, and aged chondrocytes are inferior to juvenile chondrocytes in producing cartilage-specific extracellular matrix. Mesenchymal stem cells (MSCs) are an alternative cell type that can differentiate toward the chondrocyte phenotype. Aging may influence MSC chondrogenesis but remains less well studied, particularly in the bovine system.
Bioactive Glass 13-93 as a Subchondral Substrate for Tissue-engineered Osteochondral Constructs: A Pilot Study
Replacement of diseased areas of the joint with tissue-engineered osteochondral grafts has shown potential in the treatment of osteoarthritis. Bioactive glasses are candidates for the osseous analog of these grafts.
Mechanical stimuli are of crucial importance for the development and maintenance of articular cartilage. For conditioning of cartilaginous tissues, various bioreactor systems have been developed that have mainly aimed to produce cartilaginous grafts for tissue engineering applications. Emphasis has been on in vitro preconditioning, whereas the same devices could be used to attempt to predict the response of the cells in vivo or as a prescreening method before animal studies. As a result of the complexity of the load and motion patterns within an articulating joint, no bioreactor can completely recreate the in vivo situation.
Because the injured joint has an actively inflammatory environment, the survival and repair potential of cartilage grafts may be influenced by inflammatory processes. Understanding the interactions of those processes with the graft may lead to concepts for pharmacologic or surgical solutions allowing improved cartilage repair.
We developed a tissue-engineered biphasic cartilage bone substitute construct which has been shown to integrate with host cartilage and differs from autologous osteochondral transfer in which integration with host cartilage does not occur.
Stereologic Analysis of Tibial-Plateau Cartilage and Femoral Cancellous Bone in Guinea Pigs With Spontaneous Osteoarthritis
Two strains of guinea pig develop spontaneous osteoarthritis of the knee. Although the disease evolves at different rates in the two strains, it is not known whether these differences are reflected in the structure of the cartilage and cancellous bone.
Avascular meniscal injuries are largely incapable of healing; the most common treatment remains partial meniscectomy despite the risk of subsequent osteoarthritis. Meniscal responses to injury are partially mediated through synovial activity and strategies have been investigated to encourage healing through stimulating or transplanting adjacent synovial lining. However, with their potential for chondrogenesis, synovial fibroblast-like stem cells hold promise for meniscal cartilage tissue engineering.
Frictional Properties of the Meniscus Improve After Scaffold-augmented Repair of Partial Meniscectomy: A Pilot Study
To prevent further degeneration, it is desirable to fill a meniscal defect with a supportive scaffold that mimics the mechanics of native tissue. Degradable porous scaffolds have been used, but it is unclear whether the tissue that fills the site of implantation is mechanically adequate, particularly with respect to frictional performance.
Infections after shoulder surgery are potentially devastating complications. Propionibacterium acnes is recognized as a causal agent in shoulder infections. The clinical presentation is usually insidious and nonspecific, but a P. acnes infection could be an occult cause of postoperative shoulder pain.
Limited experimental research has been performed on the treatment of avascular necrosis (AVN) by vascularized bone grafting.
The Presence of an Ossific Nucleus Does Not Protect Against Osteonecrosis After Treatment of Developmental Dysplasia of the Hip
Osteonecrosis (ON) is a major complication after treatment of developmental dysplasia of the hip (DDH). Several studies have explored the absence of the femoral head ossific nucleus at the time of hip reduction as a risk factor for the development of ON, but findings have been inconsistent.
A Quantitative Method to Assess Focal Acetabular Overcoverage Resulting From Pincer Deformity Using CT Data
Current assessment techniques for focal acetabular overcoverage are neither consistent nor quantitatively accurate.
Specific anatomic differences are believed to account for gender-specific function and health-related quality of life after TKA. However, there are conflicting data in the literature regarding these gender-specific outcomes, especially as woman appear to have surgery later in the course of the disease compared with men.
Although the severity of knee osteoarthritis (OA) usually is assessed using different measures of joint structure, function, and pain, the relationships between these measures are unclear.
Tranexamic Acid Reduces Blood Loss and Blood Transfusion after TKA: A Prospective Randomized Controlled Trial
TKA may be associated with considerable blood loss, and transfusion carries substantial risk of immunologic reaction and disease transmission. Blood transfusion also involves additional cost, therefore a reduction in its use is important. Several methods reportedly reduce postoperative blood loss and avoid homologous blood transfusion with traditional TKA approaches, but it is unclear these reductions apply to a minimally invasive technique.
Diffusion-weighted MRI Reveals Epiphyseal and Metaphyseal Abnormalities in Legg-Calvé-Perthes Disease: A Pilot Study
Legg-Calvé-Perthes disease (LCP) is thought to be associated with ischemic events in the femoral head. However, the types and patterns of reperfusion after these ischemic events are unclear.
Perioperative Infection Rate in Patients with Osteosarcomas Treated with Resection and Prosthetic Reconstruction
The incidence of perioperative infection after segmental tumor endoprosthetic replacement in previous reports varies from a high of 7.4% to a low of 2.6%. Appropriate antibiotic use for this group is unknown and controversial, whereas the relationship of antibiotic use and perioperative infection is unclear.
Osteosarcomas are the most common solid malignant bone tumors, but little is known of their origin. The embryonal rest hypothesis views cancer cells as arising from committed progenitor stem cells in each tissue. Adult tissue contains primitive stem cells that retain the ability to differentiate across dermal lines, raising the possibility that the stem cell of origin of cancers may be from a more primitive stem cell than a progenitor.
Surgical Technique: Extraarticular Knee Resection with Prosthesis–Proximal Tibia-extensor Apparatus Allograft for Tumors Invading the Knee
Intraarticular extension of a tumor requires a conventional extraarticular resection with en bloc removal of the entire knee, including extensor apparatus. Knee arthrodesis usually has been performed as a reconstruction. To avoid the functional loss derived from the resection of the extensor apparatus, a modified technique, saving the continuity of the extensor apparatus, has been proposed, but at the expense of achieving wide margins. In tumors involving the joint cavity, the entire joint complex including the distal femur, proximal tibia, the full extensor apparatus, and the whole inviolated joint capsule must be excised. We propose a novel reconstructive technique to restore knee function after a true extrarticular resection.
Growth differentiation factor-5 (GDF-5) is a key regulator of skeletogenesis and bone repair and induces bone formation in spinal fusions and nonunion applications by enhancing chondrocytic and osteocytic differentiation and stimulating angiogenesis. Elucidating the contribution of GDF-5 to fracture repair may support its clinical application in complex fractures.
Stress fractures commonly affect military recruits during basic training. Several lines of evidence suggest genetic factors are involved in stress fracture predisposition. As gender steroid hormone levels and activity have been implicated in affecting bone strength, one of the candidate genes likely to be involved is the androgen receptor gene.
Do Higher Hospital-wide Nurse Staffing Levels Reduce In-hospital Mortality in Elderly Patients with Hip Fractures: A Pilot Study
There is increasing recognition that lower nurse staffing levels are associated with higher morbidity and mortality among medical and surgical patients. The degree to which this applies to elderly patients with hip fractures is unclear.
Intraarticular injections of corticosteroids combined with local anesthetics are commonly used for management of chronic pain symptoms associated with degenerative joint diseases and after arthroscopic procedures. Several studies suggest chondrotoxicity of local anesthetics whereas others report chondroprotective and cytotoxic effects of corticosteroids on cartilage. Given the frequency of use of these agents, it is important to know whether they are in fact toxic.
Infection after ACL reconstruction is uncommon but catastrophic. Prophylactic graft saturation in vancomycin reportedly reduces infection rates.
The 2011 ABJS Nicolas Andry Award: ‘Lab’-in-a-Knee: In Vivo Knee Forces, Kinematics, and Contact Analysis
Tibiofemoral forces are important in the design and clinical outcomes of TKA. We developed a tibial tray with force transducers and a telemetry system to directly measure tibiofemoral compressive forces in vivo. Knee forces and kinematics traditionally have been measured under laboratory conditions. Although this approach is useful for quantitative measurements and experimental studies, the extrapolation of results to clinical conditions may not always be valid.
Emerging Ideas: Evaluation of Stem Cells Genetically Modified with Scleraxis to Improve Rotator Cuff Healing
Rotator cuffs heal with an interposed layer of scar tissue that makes repairs prone to failure. Cell-based biologic therapies have the potential to augment this healing process. Scleraxis (Scx) is a transcription factor that is involved in tendon development during embryogenesis, and may help drive stem cells toward tenocyte differentiation in adults.