Metaphyseal burst sign: A secondary sign on MRI of subchondral insufficiency fracture of the knee

Subchondral insufficiency fractures: overview of MRI findings from hip to ankle joint

Subchondral insufficiency fracture (SIF) represents a potentially severe condition that can advance to osteoarthritis, with collapse of the articular surface. SIF manifests as a fracture in bone weakened by non-tumorous disease, precipitated by repetitive physiological stress, without a clear history of major trauma. It is observed along the central weight-bearing region of the femoral condyle, with a higher incidence in the medial femoral condyle, but also in other large weight-bearing synovial joints, such as the femoral head, tibial plateau, or talus.A review of the literature from the past six years was performed by searching PubMed and ScienceDirect databases, using the keywords "subchondral insufficiency fracture" and "spontaneous osteonecrosis of the knee". The inclusion criteria were scientific papers presented in the English language that reported on the magnetic resonance imaging (MRI) aspects of SIF of the lower limb.Detecting SIF at the level of the hip, knee, and ankle may present challenges both clinically and radiologically. The MRI appearance is dominated by a bone marrow edema-like signal and subchondral bone changes that can sometimes be subtle. Subchondral abnormalities are more specific than the pattern of bone marrow edema-like signal and are best shown on T2-weighted and proton-density-weighted MR images. MRI plays an important role in accurately depicting even subtle subchondral fractures at the onset of the disease and proves valuable in follow-up, prognosis, and the differentiation of SIF from other conditions. · Subchondral insufficiency fractures may affect the hip, knee, and ankle.. · Subchondral insufficiency fractures may heal spontaneously or progress to collapse.. · MRI is important for the detection, follow-up, and prognosis of subchondral insufficiency fractures.. · Differential diagnosis may include transient osteoporosis and osteonecrosis of systemic origin.. · Buturoiu MM, Ghiea S, Weber M. Subchondral insufficiency fractures: overview of MRI findings from hip to ankle joint. Fortschr Röntgenstr 2024; DOI 10.1055/a-2344-5337.

Magnetic resonance imaging of subchondral insufficiency fractures in the knee (literature review)

Stress fractures are an actual problem of modern medicine. A fracture associated with insufficiency of the bone tissue of the knee condyles is a new type of stress fracture that occurs in people aged 50–55 years in response to a normal daily activity, but with damage to the weakened subchondral bone tissue of the joint caused by various reasons. This literature review is mainly based on data from foreign medical sources, since there is very little information on this type of fracture in Russian sources. This is primarily due to the fact that initially the world and Russian medical communities designated this type of fracture as a spontaneous osteonecrosis of the knee (SONK). In recent years, this term has been revised abroad and replaced by a more suitable one – subchondral insufficiency fracture of the knee (SIF/SIFK). According to modern concepts, it is necessary to clearly distinguish among the concepts of osteonecrosis and subchondral insufficiency fracture of the knee. The reason for this is not only differences in the pathogenesis of these pathologies, but also fundamentally different approaches to managing these patients. Thus, taking into account the fundamental differences in the treatment of patients with stress fracture associated with bone insufficiency and patients with osteonecrosis, and also the relevance of stress fracture of the knee condyles, we state the following aim – to study the available literature on this problem.

Treatment options for secondary osteonecrosis of the knee

Knee osteonecrosis is a debilitating progressive degenerative disease characterized by subchondral bone ischemia. It can lead to localized necrosis, tissue death, and progressive joint destruction. For this reason, it is essential to diagnose and treat this disease early to avoid subchondral collapse, chondral damage, and end-stage osteoarthritis, where the only solution is total knee arthroplasty. Three types of knee osteonecrosis have been documented in the literature: spontaneous or primitive, secondary, and post arthroscopy. Spontaneous osteonecrosis is the most common type studied in the literature. Secondary osteonecrosis of the knee is a rare disease and, unlike the spontaneous one, involves patients younger than 50 years. It presents a particular set of pathological, clinical, imaging, and progression features. The management of secondary osteonecrosis is determined by the stage of the disorder, the clinical manifestation, the size and location of the lesions, whether the involvement is unilateral or bilateral, the patient's age, level of activity, general health, and life expectancy. This review aims to present the recent evidence on treatment options for secondary osteonecrosis of the knee, including conservative treatment, joint preserving surgery, and knee replacement.