Cellular senescence refers to a stress response aiming to preserve cellular and, therefore, organismal homeostasis. Importantly, deregulation of mitochondrial homeostatic mechanisms, manifested as impaired mitochondrial biogenesis, metabolism and dynamics, has emerged as a hallmark of cellular senescence. On the other hand, impaired mitostasis has been suggested to induce cellular senescence. This review aims to provide an overview of homeostatic mechanisms operating within mitochondria and a comprehensive insight into the interplay between cellular senescence and mitochondrial dysfunction.

Many surgeons tend to believe that MRI is an accurate, non invasive diagnostic method, enough to lead to decisions for conservative treatment and save a patient from unnecessary arthroscopy. We conducted a retrospective study to investigate the accuracy of the MRI of the knee for the detection of injuries of the meniscus, cruciate ligaments and articular cartilage, in comparison with the preoperative clinical examination and intraoperative findings. Between May 2005 and February 2006 102 patients after clinical examination were diagnosed with meniscal or cruciate injury and underwent definitive treatment with arthroscopy. 46 of these patients fulfilled the inclusion criteria. The accuracy, sensitivity, specificity, negative and positive predictive values of the MRI findings were correlated with the lesions identified during arthroscopy. The diagnostic performance of the initial clinical examination was also calculated for the meniscal and cruciate ligament injuries.

Background: A number of clinical trials have been published assessing the role of iliac crest bone grafting for the management of recurrent anterior instability with glenoid bone loss in contemporary practice. We therefore performed a systematic review of contemporary literature to examine the effect of iliac crest bone grafting on postoperative outcomes of these patients. Our hypothesis is that contemporary iliac crest bone block techniques are associated with low reoperation and complication rates combined with satisfactory functional results. Methods: The US National Library of Medicine (PubMed/MEDLINE), the Cochrane Database of Systematic Reviews, and EMBASE were searched between January 2008 and December 2019 for relevant publications. Results: Following the application of the inclusion-exclusion criteria, nine articles were found eligible for our analysis. In total, 261 patients (mean age range, 25.5–37.5 years; mean follow-up range, 20.6–42 months) were included in the studies of the current review. The mean modified Coleman score was 48.6 (range 37–65), indicating an overall low-to-moderate methodological quality. In the short term, the overall all-cause reoperation rate was 6.1%, while the rate of recurrent instability was 4.8%. The graft non-union rate was 2.2%, while the rate of osteolysis, graft fracture, and infection was 0.4%, 0.9%, and 1.7%, respectively. Finally, hardware-related complications, such as screw breakage or symptomatic mechanical irritation around the screw insertion, occurred in 3.9% of the patients. Conclusions: Iliac crest bone block techniques in contemporary practice are safe and effective in the short-term (< 4 years) follow-up for the management of anterior shoulder instability with substantial glenoid bone deficiency. However, further studies of higher quality and longer follow-up are required to establish the therapeutic value of these techniques as well as to clarify whether there are differences in the outcomes of arthroscopic and open iliac crest bone block procedures.

While arthroscopic complete repair of massive rotator cuff tears (MRCT) back to their anatomic footprint is preferential, there are cases where this type of repair is not applicable due to the contraction of the torn tendons. In such cases, a non-anatomic incomplete or partial repair can be performed. A number of clinical studies have investigated the clinical and functional outcomes of arthroscopic partial repair for irreparable MRCT. To our knowledge, no systematic review has been published yet to synthetically evaluate these results. Two reviewers independently conducted the search in a PRISMA-compliant systematic way using the MEDLINE/PubMed database and the Cochrane Database of Systematic Reviews. These databases were queried with the terms “arthroscopy”[MeSH Terms] OR arthroscopic surgical procedure [Text Word (tw)] AND massive rotator cuff tears [tw] AND arthroscopic partial repair [tw]. From the 55 initial studies, we finally chose 11 clinical studies which were eligible to our inclusion-exclusion criteria. The mean modified methodology Coleman score was 58/100, whereas it ranged from 41/100 to 78/100. In total, 643 patients were included in this review. All postoperative mean clinical and functional subjective scores, as well as muscle strength of patients treated with arthroscopic partial repair, were found significantly improved, when compared with the respective mean preoperative values. The rate of structural failure of the partial repair, as it was estimated by postoperative imaging modalities, was 48.9%. The overall reoperations’ rate was 2.9% regarding the patients who were treated with partial repair. Arthroscopic partial repair might be a safe and effective alternative treatment for irreparable contracted MRCT, where a complete repair cannot be performed. The methodological quality of the relevant, available literature is low to moderate; therefore, further studies of higher quality are required to confirm these results.

Osteoarthritis is a degenerative joint disease affecting middle-aged and elderly patients. It mainly involves weight-bearing joints such as the hip, knee and spine as well as the basilar joint of the thumb, causing dysfunction and painful symptoms. Often, joint arthritis is accompanied by cartilage defects, joint space narrowing, osteophytes, bone sclerosis and subchondral bone cysts (SBC). The aim of the present study was to explore the pathophysiology responsible for the development of SBCs as well as the association between SBCs and disease progress, the level of clinical symptoms and their impact on postoperative outcomes and risk of possible complications following joint replacements if left untreated. A literature review on PubMed articles was conducted to retrieve and evaluate all available evidence related to the main objective mentioned above. A few theories have been put forth to explain the formation process of SBCs. These involve MMPs secretion, angiogenesis, and enhanced bone turnover as a biological response to abnormal mechanical loads causing repeated injuries on cartilage and subchondral tissue during the development of arthritis. However, the application of novel therapeutics, celecoxib-coated microspheres, local administration of IGF-1 and activated chondrocytes following surgical debridement of SBCs hinders the expansion of SBCs and prevents the progression of osteoarthritis.

Neurofibromatosis type 1 (NF1), which is the most common phacomatoses, is an autosomal dominant disorder characterized by clinical presentations in various tissues and organs, such as the skin, eyes and nervous and skeletal systems. The musculoskeletal implications of NF1 include a variety of deformities, including scoliosis, kyphoscoliosis, spondylolistheses, congenital bony bowing, pseudarthrosis and bone dysplasia. Scoliosis is the most common skeletal problem, affecting 10–30% of NF1 patients. Although the pathophysiology of spinal deformities has not been elucidated yet, defects in bone metabolism have been implicated in the progression of scoliotic curves. Measurements of Bone Mineral Density (BMD) in the lumbar spine by using dual energy absorptiometry (DXA) and quantitative computer tomography (QCT) have demonstrated a marked reduction in Z-score and osteoporosis. Additionally, serum bone metabolic markers, such as vitamin D, calcium, phosphorus, osteocalcin and alkaline phosphatase, have been found to be abnormal. Intraoperative and histological vertebral analysis confirmed that alterations of the trabecular microarchitecture are associated with inadequate bone turnover, indicating generalized bone metabolic defects. At the molecular level, loss of function of neurofibromin dysregulates Ras and Transforming Growth factor-β1 (TGF-β1) signaling and leads to altered osteoclastic proliferation, osteoblastic activity and collagen production. Correlation between clinical characteristics and molecular pathways may provide targets for novel therapeutic approaches in NF1.