Context:Stress fractures are common injuries in athletes, often difficult to diagnose. A stress fracture is a fatigue-induced fracture of bone caused by repeated applications of stress over time.Evidence Acquisition:PubMed articles published from 1974 to January 2012.Results:Intrinsic and extrinsic factors may predict the risk of stress fractures in athletes, including bone health, training, nutrition, and biomechanical factors. Based on their location, stress fractures may be categorized as low- or high-risk, depending on the likelihood of the injury developing into a complete fracture. Treatment for these injuries varies substantially and must account for the risk level of the fractured bone, the stage of fracture development, and the needs of the patient. High-risk fractures include the anterior tibia, lateral femoral neck, patella, medial malleolus, and femoral head. Low-risk fractures include the posteromedial tibia, fibula, medial femoral shaft, and pelvis. Magnetic resonance is the imaging test of choice for diagnosis.Conclusions:These injuries can lead to substantial lost time from participation. Treatment will vary by fracture location, but most stress fractures will heal with rest and modified weightbearing. Some may require more aggressive intervention, such as prolonged nonweightbearing movement or surgery. Contributing factors should also be addressed prior to return to sports.

Background: Sarcopenia, an age-related loss of muscle mass and function, has been previously linked to an increased risk of morbidity, mortality, and infection after a variety of surgical procedures. This study is the first to evaluate the impact of the psoas-lumbar vertebral index (PLVI), a validated marker for central sarcopenia, on determining post-arthroplasty infection status. Methods: This is a case-control, retrospective review of 30 patients with prosthetic joint infection (PJI) diagnosed by the Musculoskeletal Infection Society criteria compared to 69 control patients who underwent a total hip or knee arthroplasty. All patients had a recent computed tomography scan of the abdomen/pelvis to calculate the PLVI. PLVI was evaluated alongside age, gender, body mass index, Charlson Comorbidity Index, American Society of Anesthesiologists score, and smoking status to determine the predictive value for infection. Results: Notably, the infected group had a large, significant difference in their average PLVI (0.736 vs 0.963, P < .001). The patient's PLVI was a predictor of infection status, with a higher PLVI being protective against infection (odds ratio [OR] 0.28, 95% confidence interval [CI] 0.109-0.715, P ¼ .008). Additional predictors of infection status were higher American Society of Anesthesiologists score (OR 10.634, 95% CI 3.112-36.345, P < .001) and Charlson Comorbidity Index (OR 1.438, 95% CI 1.155-1.791, P ¼ .001). Multivariate, binary logistic regression analysis confirmed that PLVI was a significant independent predictor of infection status (B ¼ À0.685, P ¼ .039). Conclusion: PLVI, a marker for central sarcopenia, was demonstrated to be a risk factor for PJI. Further research and consideration of sarcopenia as a screening and optimizable risk factor for total joint arthroplasty must be explored.

Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.