With correct indications, OWHTO is a reliable procedure for medial knee arthritis/overload. The outcomes reported are similar to those from other studies, although the variables related to outcomes are slightly different.

Revision total knee arthroplasty (TKA) is the treatment of choice in patients with periprosthetic joint infection. It may be performed in either a single stage or two stages. In the latter option, between stages, an antibiotic-loaded spacer may be used to maintain a certain amount of joint stability and mobility after the infected implant is removed, adding an intra-articular concentration of antibiotics. There are two types of antibiotic-loaded cement spacers: static and dynamic. Static spacers basically create a temporary arthrodesis with antibiotic-loaded cement and usually are handmade within the surgical field. Dynamic spacers can be created intraoperatively by using different tools or may be prepackaged by the manufacturer; they allow range of motion between stages. In this article, the authors review the indications, surgical techniques, and results for static and dynamic spacers in two-stage revision TKA.

Background The use of allogenic juvenile chondrocytes or autologous chondral fragments has shown promising laboratory results for the repair of chondral lesions. Hypothesis/Purpose The purpose of the study was to evaluate in vitro the extracellular matrix production of mixed adult/juvenile cultures of both chondrocytes (part 1) and minced cartilage fragments (part 2). The authors hypothesized that juvenile chondrocytes would not affect matrix production when mixed with adult chondrocytes or cartilage fragments. Study design Controlled laboratory study. Methods Cartilage sources consisted of three adult and three juvenile (human) donors. In part 1, per each donor, juvenile chondrocytes were mixed with adult chondrocytes in five different proportions: 100, 50, 25, 12.5 and 0 %. Three-dimensional cultures in low melt agarose were performed. At 6 weeks, biochemical and histological analyses were performed. In part 2, isolated adult, isolated juvenile, and mixed three-dimensional cultures (1:1) were performed with chondral fragments (<1mm), both with low melt agarose and a hyaluronic acid scaffold. At 2 and 6 weeks, cultures were evaluated with biochemical and histological analyses. Results Part 1: biochemical and histological analyses showed that isolated juvenile cultures performed significantly better than mixed and isolated adult cultures. No significant differences were noted between mixed cultures (1:1) and isolated adult cultures. Part 2: biochemical and histological results at 6 weeks showed that mixed cartilage fragment cultures performed better than isolated adult cultures in terms of PG/DNA ratio (p=0.014), percentage of safranin-O positive cells (p=0.012), Bern score (p=0.001), and Collagen type II. No statistical difference was noted between juvenile and mixed cultures. Conclusion Extracellular matrix production of juvenile chondrocytes is inhibited by adult chondrocytes. The addition of juvenile cartilage fragments to adult fragments improves matrix production, with a positive interaction between the two sources. Clinical relevance Even if the underlying mechanisms are still unknown, this study describes the behavior of juvenile/adult co-cultures using both chondrocytes and cartilage fragments, with potential for new research and clinical applications.

Outgrowing cells may represent a subset of chondrocytes undergoing a phenotypic shift towards a proliferative state. TGF-β1, and to a greater extent G-CSF, may accelerate this outgrowth. The clinical relevance of this study may involve a potential future clinical application of scaffolds preloaded with growth factors as an additional coating for chondral fragments. Indeed, a controlled delivery of G-CSF, widely employed in various clinical settings, might improve the repair process driven by minced human cartilage fragments during one-stage cartilage repair.

Shoulder stiffness is a condition of painful restriction of the glenohumeral range of motion. Numerous risk factors for primary and postoperative shoulder stiffness have been described. This article summarizes the known aspects of the pathophysiology of shoulder stiffness, with special attention to elements of molecular biology and genetics, which could influence the risk of developing shoulder stiffness. Furthermore, the role of hormonal and metabolic factors, medical disorders, drugs, and of other published risk factors for primary and postoperative shoulder stiffness is reviewed and discussed. Finally, aspects related to shoulder surgery and postoperative rehabilitation protocols, which could influence the development of postoperative stiffness are presented.