Clinical and Pathophysiologic Significance of MRI Identified Bone Marrow Lesions Associated with Knee Osteoarthritis.

Knee osteoarthritis (OA) affects the joint beyond just the articular cartilage. Specifically, magnetic resonance imaging-identified bone marrow lesions (BML) in the subchondral bone have both clinical and pathophysiological significance. Compared to joint space narrowing on traditional radiographs, the presence of BMLs has been better correlated with severity of clinical symptoms as well as clinical deterioration. Presence of a BML increases the likelihood for progression to a total knee arthroplasty by up to nine fold. Histochemical analysis of BMLs has shown increased levels of tumor necrosis factor-alpha, matrix metalloproteinases and substance P, thought to stimulate pain receptors in osteoarthritis. LEVEL OF EVIDENCE: V.

The risk factors and an evidence-based protocol for the management of persistent wound drainage after total hip and knee arthroplasty.

BACKGROUND: Persistent wound drainage (PWD) is one of the major risk factors for periprosthetic joint infections (PJIs), arguably the most dreaded complication after total joint arthroplasty (TJA). The aim of this study was to identify the risk factors for PWD and provide a stepwise management protocol for it. METHODS: A retrospective review of 4873 TJAs was performed. After determining patients with PWD, a logistic regression model was designed to identify the risk factors using Charlson and Elixhauser comorbidity indexes. Finally, the protocol that was instituted for the management of PWD and its success rate was presented. RESULTS: The prevalence of PWD was 6.2% (302 of 4873). Of these, 196 did not require any surgical interventions, and drainage stopped with local wound care. 106 patients required surgical intervention, of which, 64 underwent superficial irrigation and debridement and 42 underwent deep irrigation and debridement with modular components exchange. Patients with PWD had significantly higher rates of PJI (odds ratio [OR]: 16.9; 95% confidence interval [CI]: 9.1-31.6). Risks factors were diabetes (OR: 21.2; 95% CI: 12.8-25.1), morbid obesity (OR: 17.3; 95% CI: 14.7-21.5), rheumatoid arthritis (OR: 14.2; 95% CI: 11.7-16.5), chronic alcohol use (OR: 4.3; 95% CI: 2.3-6.1), hypothyroidism (OR: 2.8; 95% CI: 1.3-4.2), and female gender (OR: 1.9; 95% CI: 1.1-2.2). CONCLUSIONS: Several modifiable risk factors of PWD were identified. Surgeons must be cognizant of these comorbidities and optimize patients' general health before an elective TJA. Our results demonstrated that PWD ceased in about 65% of the patients with local wound care measures alone. Patients with PWD were at substantially higher risk for PJI.