Corticosteroids are the most common etiological factor in nontraumatic avascular necrosis (AVN) of bone, accounting for about 10% of arthroplasties performed annually in the United States. Evidence is conflicting on the relative importance of peak dose, daily dose, or cumulative dose, and most likely all three represent "high dose" corticosteroid administration and play a role in AVN. The etiology may be multifactorial with corticosteroids superimposed on genetic or pathological predispositions. Joint preservation depends upon early diagnosis and treatment before fracture of the subchondral trabeculae and joint incongruity. Early intervention depends upon identifying at-risk patients and quantifying their risk by understanding clinical and pathophysiological contributions to that risk. Our data and that of others suggest that a screening MRI of at-risk populations will permit detection of AVN at a prefracture stage when preservation of the joint is possible.

DCE-MRI can quantitatively assess subchondral bone perfusion kinetics in human OA and identify heterogeneous regions of perfusion deficits. The results are consistent with venous stasis in OA, reflecting venous outflow obstruction, and can affect intraosseous pressure, reduce arterial inflow, reduce oxygen content, and may contribute to altered cell signaling in, and the pathophysiology of, OA.

The role of arthroscopic partial meniscectomy (APM) in reducing pain and improving function in patients with meniscal tears remains controversial. Five recent high-quality randomized controlled trials (RCTs) compared non-operative management of meniscal tears to APM, with four showing no difference and one demonstrating superiority of APM. In this review, we examined the strengths and weaknesses of each of these RCTs, with particular attention to the occurrence of inadvertent biases. We also completed a quantitative analysis that compares treatment successes in each treatment arm, considering crossovers as treatment failures. Our analysis revealed that each study was an excellent attempt to compare APM with non-surgical treatment but suffered from selection, performance, detection, and/or transfer biases that reduce confidence in its conclusions. While the RCT remains the methodological gold standard for establishing treatment efficacy, the use of an RCT design does not in itself ensure internal or external validity. Furthermore, under our alternative analysis of treatment successes, two studies had significantly more treatment successes in the APM arm than the non-operative arm although original intention-to-treat analyses showed no difference between these two groups. Crossovers remain an important problem in surgical trials with no perfect analytical solution. With the studies available at present, no conclusion can be drawn concerning the optimal treatment modality for meniscal tears. Further work that minimizes significant biases and crossovers and incorporates sub-group and cost-benefit analyses may clarify therapeutic indications.