➤ Although multiple theories have been proposed, no one pathophysiologic mechanism has been identified as the etiology for the development of osteonecrosis of the femoral head. However, the basic mechanism involves impaired circulation to a specific area that ultimately becomes necrotic.➤ A variety of nonoperative treatment regimens have been evaluated for the treatment of precollapse disease, with varying success. Prospective, multicenter, randomized trials are needed to evaluate the efficacy of these regimens in altering the natural history of the disease.➤ Joint-preserving procedures are indicated in the treatment of precollapse disease, with several studies showing successful outcomes at mid-term and long-term follow-up.➤ Studies of total joint arthroplasty, once femoral head collapse is present, have described excellent outcomes at greater than ten years of follow-up, which is a major advance and has led to a paradigm shift in treating these patients.➤ The results of hemiresurfacing and total resurfacing arthroplasty have been suboptimal, and these procedures have restricted indications in patients with osteonecrosis of the femoral head.

Fournier's gangrene (FG) is a rare but life threatening disease. Although originally thought to be an idiopathic process, FG has been shown to have a predilection for patients with diabetes as well as long term alcohol misuse; however, it can also affect patients with non-obvious immune compromise. The nidus is usually located in the genitourinary tract, lower gastrointestinal tract, or skin. FG is a mixed infection caused by both aerobic and anaerobic bacterial flora. The development and progression of the gangrene is often fulminating and can rapidly cause multiple organ failure and death. Because of potential complications, it is important to diagnose the disease process as early as possible Although antibiotics and aggressive debridement have been broadly accepted as the standard treatment, the death rate remains high.

Successful total knee arthroplasty (TKA) has often been based on the restoration of the knee to neutral alignment postoperatively. Numerous reports have linked malaligned TKA components to increased wear, poor functional outcomes, and failure. There have been many different alignment philosophies and surgical techniques that have been established to attain the goal of proper alignment, which includes such techniques as computerized navigation, and custom cutting guides. In addition, these methods could potentially have the added benefit of leading to improved functional outcomes following total knee arthroplasty. In this report, we have reviewed and analyzed recent reports concerning mechanical, anatomic, and kinematic axis/alignment schemes used in total knee arthroplasty.

Background Aseptic loosening is the most common cause for revisions after lower-extremity total joint arthroplasties, however studies differ regarding the degree to which host factors influence loosening. Questions/purpose We performed a systematic review to determine which host factors play a role in the development of clinical and/or radiographic failure from aseptic loosening after (1) THA and (2) TKA. Methods Two searches on THA and TKA, respectively, using four electronic databases (EMBASE, CINAHL Plus, PubMed, and Scopus) were conducted. We identified a total of 209 reports that encompassed nine potential host factors affecting aseptic loosening. Inclusion criteria for consideration of scientific clinical reports were that 20 or more patients were involved, with more than 1-year followup, with at least three studies pertaining to each factor, and at least six of the Methodological Index for Non-randomized Studies criteria met, and with raw data for odds ratio (OR) calculations. Twenty-one studies (16 THA studies with 45,779 hips and five TKA studies with 288 knees, respectively) were used to calculate weighted OR and CIs (using the random effects theory) and study heterogeneity for four different host factors in THAs (male sex, high activity level, obesity defined as BMI C 30 kg/m 2 , and current or former tobacco use) and one factor in TKA (BMI C 30 kg/m 2 ), which were placed in a forest plot. Results For THA, male sex (OR, 1.39; 95% CI, 1.22-1.58; p = 0.001) and high activity level (University of California Los Angeles [UCLA] activity score C 8 points; OR, 4.24; 95% CI, 2.46-7.31; p = 0.001) were associated with aseptic loosening. However, obesity (OR, 1.01; 95% CI, 0.73-1.40; p = 0.96), and tobacco use (OR, 1.96; 95% CI, 0.43-8.97; p = 0.39) were not associated with an increased risk of aseptic loosening after THA with the numbers available. For TKA, we found no host factors associated with loosening. In particular, obesity (BMI C 30 kg/m 2

Rehabilitation following total knee arthroplasty (TKA) continues to pose a challenge for both patients and providers. In addition, guidelines vary considerably between institutions, which often leave therapy regimens to the discretion of the provider. The lack of clear guidelines for rehabilitation may contribute to inadequate recovery of strength and range-of-motion, resulting in less optimal functional outcomes. Therefore, the aim of this review was to highlight and discuss a variety of post-TKA rehabilitative modalities currently available and to provide evidence regarding efficacy and practicality. Specifically, we assessed the role of and evidence for exercise therapy, aquatic therapy, balance training, continuous passive motion, cold therapy and compression, neuromuscular electrical stimulation, transcutaneous electrical nerve stimulation, and instrument-assisted soft-tissue therapy. Additionally, we proposed general recommendations for rehabilitation after TKA, and as we specifically described active and obese patients, we have included guidelines for these subsets as well. Our review examines the various rehabilitative modalities to offer suggestions for recovery of strength and range-of-motion after TKA, with a focus on the early incorporation of exercise therapy, balance training, aquatic therapy, cryopneumatic therapy, neuromuscular electrical stimulation, and transcutaneous electrical nerve stimulation. Dedication and commitment to rehabilitation may help patients attain and exceed their preoperative activity levels.