This study describes a modified AMIC technique consisting of perforations according to Pridie, rather than microfractures, and the covering of the focus of the lesion with a biological collagen patch enriched with bone marrow blood drawn through the knee itself. This technique allows advantages of both the Pridie technique and the in situ proliferation of mesenchymal cells beneath a biological collagen membrane, 'augmented', with bone marrow blood. The collagen membrane forms the roof of a 'biological chamber', and serves to protect and contains the stem cells as they differentiate into chondrocytes, which will form a healthy regenerative cartilage.

Arthroscopic surgery for patients with patellar tendinopathy, refractory to nonoperative management, appears to provide significant improvements in symptoms and function, with improvements maintained for at least 3 years. These results suggest that some patients may not be able to achieve their presymptom sporting level; or if they do, they may participate in sports with some degree of residual symptoms. Limited data show that these improvements are maintained for up to 10 years. Early return to sports may also be achieved.

We report a case of bilateral displaced acetabular fractures including both columns fractures with protrusio acetabuli in a female patient, aged 15 years, with osteogenesis imperfecta (OI) (Sillence Type I), epilepsy, blue sclera and bilateral ipoacusia. Since OI is a rare genetic disorder characterized by an increased propensity to osteopenia, intraoperative fracture risks and hemorrhagic diathesis, we opted for the open reduction and internal fixation of the acetabula in two surgical steps and using two different approaches. Although the clinical outcomes are not excellent in this report (HHS 45/100), the authors suggest that chances of a good outcome with reconstruction of the acetabulum must be balanced against the benefits of early or late total hip arthroplasty. The goal was to delay a joint replacement as long as possible due to the patient's young age.Level of evidence: V, case report.

Muscle injuries are the most common trauma in team and individual sports. The muscles most frequently affected are those of the lower limb, and in particular hamstrings, adductors, rectus femoris and calf muscles. Although several scientific studies have tried to propose different rehabilitation protocols, still too often the real rehabilitation process is not based on scientific knowledge, especially in non-elite athletes. Moreover, the growing use of physical and instrumental therapies has made it increasingly difficult to understand what can be truly effective. Therefore, the aim of the present paper is to review proposed therapeutic algorithms for muscle injuries, proposing a concise and practical summary. Following a three-phase rehabilitation protocol, this review aims to describe the conservative treatment of indirect structural muscle injuries, which are the more routinely found and more challenging type. For each phase, until return to training and return to sport are completed, the functional goal, the most appropriate practitioner, and the best possible treatment according to current evidence are expressed. Finally, the last section is focused on the specific exercise rehabilitation for the four main muscle groups with a structured explanatory timetable.

Giant cell tumors of bone (GCTB) are rare sarcomas with a high rate of unpredictable local relapse. Studies suggest that surgical methods affect recurrence, supporting the idea that local disease develops from re-growth of residual cancer cells. To identify early prognostic markers of individual risk of recurrence, we evaluated the effect of post-surgery fluids from a cohort of GCTB patients on growth of primary and established sarcoma cell lines, and mice xenograph. Post-surgery fluids increased cell growth and enhanced expression of CD44++, the principal receptor for the extracellular matrix component hyaluronan and the mesenchymal stem marker CD117+. Cancer cells became highly invasive and tumorigenic, acquiring stemness properties, and activated AKT/mTOR pathway. Prolonged stimulation with post-surgery fluids down-regulated the mesenchymal gene TWIST1 and Vimentin protein, and transdifferentiated cells into tubule-like structures positive to the endothelial markers VE-Cadherin and CD31+. In mice, post-surgery fluids gave rise to larger and more vascularized tumors than control, while in patients AKT/mTOR pathway activation was associated with recurrence by logistic regression (Kaplan-Meier; P<0.001). These findings indicate that post-surgery fluids are an adjuvant in mechanisms of tumor regrowth, increasing stem cell growth and AKT/mTOR activity.