Osteoarthritis is a heterogeneous disease characterized by variable clinical features, biochemical/genetic characteristics, and responses to treatments. To optimize palliative effects of current treatments and develop efficacious disease-modifying interventions, treatments may need to be tailored to the individual or a subset of osteoarthritic joints. The purpose of this review is to explore the current literature on the clinical and physiological variability in osteoarthritis and potential for stratifying patients. Several stratifications have been reported, including mechanism of onset, stage of disease progression, involved joints, inflammatory levels, and effusion. Most of these methods revealed two to three unique subsets of osteoarthritis. Osteoarthritic joints may be stratified by an array of variables, some transient and others consistent throughout the disease process. Future research needs to continue to explore stratification techniques since these may be the key to optimizing palliative interventions and developing disease-modifying interventions for subsets within this heterogeneous disease.

Although OA prevalence was higher in the surgical treatment group at a mean follow-up of 11.8 years, no definitive evidence supports surgical or nonsurgical treatment after anterior cruciate ligament injury to prevent posttraumatic OA. Current studies have been limited by small sample sizes, low methodologic quality, and a lack of data regarding confounding factors.

Vascular injuries following total hip arthroplasty (THA) are very rare, with pseudoaneurysm being a small subset. We report a case of profunda femoris artery (PFA) pseudoaneurysm in a 61-year-old male following a posterior approach revision left THA. Presentation involved continued blood transfusion requirements several weeks postoperatively. Diagnosis of the pseduoaneurysm was made by contrast CT of the lower extremity, with confirmation via IR angiography. Successful embolization was achieved with selective coiling and Gelfoam. Presenting complaints of such complications are often vague and therefore lead to delayed diagnosis. Causes of such complications are not completely understood, particularly with PFA injuries in THA. Possible mechanisms are discussed in this paper. Vascular complications following THA can be difficult to diagnose. High suspicion in the setting of continued postoperative pain or bleeding may allow prompt diagnosis and avoidance of serious limb-threatening complications.

BackgroundSeveral symptom-relieving interventions have been shown to be efficacious among osteoarthritis (OA) patients with knee effusion; however, not every symptomatic knee OA patient has clinical effusion. Results may be over-generalized since it is unclear if effused knees represent a unique pathological condition or subset compared to knees without effusion. The primary purpose of this study was to determine if biochemical differences existed between OA knees with and without effusion.MethodsThe present cross-sectional study consisted of 22 volunteers (11 with knee effusion, 11 without knee effusion) with confirmed late-stage radiographic knee OA (Kellgren-Lawrence score ≥ 3). Synovial fluid samples were collected and analyzed using a custom multiplex enzyme-linked immunosorbent assay to determine eight specific biomarker concentrations (e.g., catabolic, anabolic).ResultsMatrix metalloproteinase (MMP)-3, tissue inhibitor of MMPs (TIMP)-1, TIMP-2, and interleukin-10 were significantly higher in the knees with effusion than in the knees without effusion.ConclusionsThe biochemical differences that existed between knees with and without effusion provide support that OA subsets may exist, characterized by distinct biochemical characteristics and clinical findings (e.g., effusion).

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IntroductionGlobally, knee osteoarthritis (OA) is among the top 15 causes of disability. A patient with a history of macrotrauma is more than four times as likely to develop knee OA. Macrotrauma initiates a cascade of biochemical and biomechanical changes in the joint that interact and can lead to joint failure. The purpose of this critical review is to present an overview of the early pathophysiological (i.e. biomechanical and biochemical) changes that typically occur after a knee injury and the implications of these changes for early-stage OA interventions.

Context Joint trauma is a risk factor for osteoarthritis (OA), which is becoming an increasingly important orthopedic concern for athletes and nonathletes alike. For advances in OA prevention, diagnosis, and treatment to occur, a greater understanding of the biochemical environment of the affected joint is needed. Objective To demonstrate the potential of a biochemical technique to enhance our understanding of and diagnostic capabilities for osteoarthritis. Design Cross-sectional. Setting Outpatient orthopedic practice. Participants 8 subjects: 4 OA-knee participants (65 ± 6 y of age) and 4 normal-knee participants (54 ± 10 y) with no history of knee OA based on bilateral standing radiographs. Intervention The independent variable was group (OA knee, normal knee). Main Outcome Measures 16 knee synovial-protein concentrations categorized as follows: 4 as pro-inflammatory, or catabolic, cytokines; 5 as anti-inflammatory, or protective, cytokines; 3 as catabolic enzymes; 2 as tissue inhibitors of metalloproteinases [TIMPs]; and 2 as adipokines. Results Two anti-inflammatory cytokines (interleukin [IL]-13 and osteoprotegerin) and a pro-inflammatory cytokine (IL-1β) were significantly lower in the OA knees. Two catabolic enzymes (matrix metalloproteinase [MMP]-2 and MMP-3) were significantly elevated in OA knees. TIMP-2, an inhibitor of MMPs, was significantly elevated in OA knees. Conclusions Six of the 16 synovial-fluid proteins were significantly different between OA knees and normal knees in this study. Future research using a similar multiplex ELISA approach or other proteomic techniques may enable researchers and clinicians to develop more accurate biochemical profiles of synovial fluid to help diagnose OA, identify subsets of OA or individual characteristics, guide clinical decisions, and identify patients at risk for OA after knee injury.

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