Knee subchondroplasty for management of subchondral bone cysts: a novel treatment method

Knee subchondroplasty (SCP) is one of the most novel minimally invasive methods for treating bone marrow lesions. The literature suggests that it is safe, with few complications and good outcomes. However, no studies have documented its usage for managing large subchondral bone cysts. This article outlines a case report and details the pearls and pitfalls of SCP in treating large subchondral bone cysts. Our patient underwent arthroscopic debridement with medial femoral condyle SCP. Mild posterior extravasation of synthetic bone substitute was observed on Postoperative Day 1, which was immediately rectified on revision arthroscopy. Gradual escalation of weight bearing and good pain relief were subsequently achieved, and the patient has remained complication-free after two years. No further extravasation were observed on repeat radiography. SCP is a feasible temporising measure that may help to delay the need for bone allograft or immediate knee arthroplasty in younger patients while retaining function and delaying loss of productivity.

Bone marrow lesions: etiology and pathogenesis at the hip

Bone marrow lesions (BML) are painful changes in subchondral bone which can be reliably identified on magnetic resonance imaging and have been identified in patients suffering from hip osteoarthritis (OA) and related conditions. Created via repetitive microdamage at the articular surface and dysregulated subchondral healing, BML have been linked to traumatic, inflammatory, degenerative, metabolic and neoplastic processes. While BML are known to be a common pathology throughout the body, BML at the hip have not been extensively studied in comparison to those at the knee. Due to the hip’s unique biomechanical architecture, function and loading, and independent risk factors leading to hip OA, hip BMLs must be independently understood. The identification of BML in the setting of a pre-osteoarthritic condition may provide a target for treatment and prevention of joint degeneration. By continuing to define and refine the relationships between BML, subchondral bone cysts and OA, prevention, diagnosis and treatment of OA could shift, leading to an improved quality of life and increased longevity of individuals’ native hips.

Impact of Size and Shape of Equine Femoral Subchondral Bone Cysts With a Transcondylar Screw on Predicted Bone Formation Area in a Finite Element Model

Equine subchondral bone cysts (SBCs) develop most often in the medial femoral condyle (MFC) of yearlings intended for performance. SBCs often cause lameness and can cause secondary injuries to the meniscus and tibial cartilage. A novel surgical technique using a transcondylar lag screw (TLS) across an MFC SBC has shown success in lameness resolution and radiographic healing of MFC SBC. In a previous study using finite element analysis, our lab showed that a TLS stimulated bone formation on the inner surface of the SBC and altered third principal stress vectors to change the direction of surface compression to align with the screw axis. This work extended the previous study, which was limited by the use of only one idealized SBC. Our objective was to test SBCs of several sizes and shapes in a newly developed equine stifle FEM with a TLS to determine how cyst size affects bone formation stimulation. This study found that a transcondylar screw is most effective in stimulating bone formation in cysts of greater height (proximal-distal). The TLS increases stress stimulus in the bone around the cyst to promote bone apposition and directs compression across the cyst. If full penetration of the screw through the cyst is possible, it is recommended that the transcondylar screw be used to treat subchondral bone cysts. For the treatment of smaller cysts that are not accessible by the current screw surgical approach, future work could study the efficacy of a dual-pitch headless screw that may reach smaller cysts.

Proteome Alterations in Equine Osteochondrotic Chondrocytes

Osteochondrosis is a failure of the endochondral ossification that affects developing joints in humans and several animal species. It is a localized idiopathic joint disorder characterized by focal chondronecrosis and growing cartilage retention, which can lead to the formation of fissures, subchondral bone cysts, or intra-articular fragments. Osteochondrosis is a complex multifactorial disease associated with extracellular matrix alterations and failure in chondrocyte differentiation, mainly due to genetic, biochemical, and nutritional factors, as well as traumas. This study describes the main proteomic alterations occurring in chondrocytes isolated from osteochondrotic cartilage fragments. A comparative analysis performed on equine osteochondrotic and healthy chondrocytes showed 26 protein species as differentially represented. In particular, quantitative changes in the extracellular matrix, cytoskeletal and chaperone proteins, and in cell adhesion and signaling molecules were observed in osteochondrotic cells, compared to healthy controls. Functional group analysis annotated most of these proteins in “growth plate and cartilage development”, while others were included in “glycolysis and gluconeogenesis”, “positive regulation of protein import”, “cell–cell adhesion mediator activity”, and “mitochondrion nucleoid”. These results may help to clarify some chondrocyte functional alterations that may play a significant role in determining the onset and progression of equine osteochondrosis and, being related, of human juvenile osteochondrosis.

Ultrasonography of the stifle

Stifle injuries are increasingly recognised as a major cause of hind limb lameness and commonly affect the soft tissues of the joint in adult horses, making ultrasonography a vital part of diagnostic imaging of this joint. This article aims to provide an introduction to stifle ultrasonography. To ensure comprehensive evaluation of the stifle, a systematic approach is necessary. The ultrasonographic examination is divided into five approaches: initially weight-bearing scans should be obtained of the cranial aspect (for the femoropatellar joint), medial aspect (for the medial femorotibial joint), and lateral aspect (for the lateral femorotibial joint), followed by flexed views from cranial (for the cranial aspect of the femorotibial joints) and, finally, in limited cases because pathology is rarer and the technique more demanding, weight-bearing views of the caudal aspect (for the caudal parts of both femorotibial joints). For the femoropatellar joint, ultrasound can be used to identify bruising (haematoma), injuries to the patellar ligaments, trochlear ridges (including osteochondrosis), and patella and tibial crest fractures. For the femorotibial joints, injuries to the menisci are the most common, but ultrasound can also identify rarer collateral and cruciate ligament injuries. and abnormalities of the weight-bearing surfaces of the femoral condyles, such as cartilage damage and subchondral bone cysts.