Diagnostic Accuracy of Dual-energy CT for Bone Marrow Edema in Patients with Acute Knee Injuries: A Systematic Review and Meta-analysis

Background: The prevalence of knee injury is high and early diagnosis is significant to guide clinical treatment. MRI is recognized as the gold standard for detecting bone marrow edema (BME) in patients with acute knee injury, but limitations still exist. Dual-energy CT (DECT) is investigated as a promising alternative.Methods: We systematically retrieved studies from EMBASE, Scopus, PUBMED, and the Cochrane Library and collected gray literatures. According to PRISMA-DTA guidelines, a systematic review was performed from inception to July 31, 2021, assessing the diagnostic accuracy of DECT for detecting BME in at least 10 adult patients with acute knee injuries and with an MRI reference standard. Study details were independently extracted by two reviewers. Meta-analysis was performed using a bivariate mixed-effects regression model with subgroup analysis performed to evaluate for sources of variability. Results: Nine studies evaluating 290 patients between the ages of 23–53 with acute knee injuries undergoing DECT and MRI were included in analysis. Summary sensitivity, specificity, and AUC values for BME were 85% (95% confidence interval (CI) 77–90%), 96% (95% CI 93–97%), and 0.97 (95% CI 0.95–0.98), respectively. There were no statistically significant differences in specificity and sensitivity amongst comparative subgroups to account for presumed variability amongst studies.Conclusion: DECT is accurate for detecting BME in patients with acute knee injuries and can be used as an alternative to MRI, particularly when MRI is contraindicated or unavailable.

Role of the Popliteal Fossa in Knee Problems: Theoretical Considerations and Practical Implications

The popliteal fossa is located at the back of the knee joint and it is an area where blood vessels and nerves and also lymph nodes pass. Popliteal fossa injuries includes nearly 2% of acute knee injuries. The treatment of chronic injuries are always more difficult than acute ones, because its diagnosis would depend on careful interpretation of specific clinical exams. In this review, we describe our current understanding of role of popliteal fossa in knee problems, and summarize the anatomy and functional role of popliteal fossa and popliteomeniscal fibers, and mechanism of popliteomeniscal fibers injuries, and discuss strategies for diagnosis of popliteomeniscal fibers lesions, differential diagnosis, and treatment of the posterolateral corner injuries.

Validity of Ottawa Knee Rules at a Teaching Hospital of Eastern Nepal

Introduction: Knee injuries are encountered frequently in Orthopedic emergency and Outpatient departments. Radiographs are routinely ordered in them, but not all of them demonstrate clear fractures. The decision for radiography based on subjective evaluation can help to reduce cost, decrease waiting time, and unnecessary radiation exposure. We lack this information in our context. Objective: The objective of this study was to find the validity of the Ottawa knee rule (OKR) in patients presenting with acute knee injuries at a teaching hospital in eastern Nepal. Methodology: A cross-sectional study was conducted from March 2018 to February 2019 including 210 cases of acute knee injuries. The patients were evaluated as per OKR and their X-rays were evaluated too. Collected data were entered in MS Excel and analyzed by SPSS for validity. Results: Out of the total of 210 eligible patients (122 males and 88 females) with a mean age of 43.97 years, the radiography rate was 100% but the yield rate was only 10.5%. Overall 69% of patients presented to the hospital within 24 hours of the injury and direct hit/trauma was the commonest mode of injury. Patella fractures were commonest followed by proximal tibia fractures. There was a high sensitivity of 100% and a specificity of 42.02%. The rule yielded a Positive and Negative Predictive value of 16.79% and 100%, respectively. The OKR, if applied correctly, could result in radiography rate reduction by 37.61%. The Fisher exact test result was significant at p<0.05. Conclusion: OKRs is a valid tool to predict fractures in patients who has a history of acute knee injuries without chances of missing fractures. This rule can reduce unnecessary radiography in our setup as well.

Patella dislocation: an overview

Patella dislocation is one of the most common knee injuries, accounting for 3% of acute knee injuries. Despite its prevalence, patella dislocation is often missed, with a haemarthrosis often the only sign, albeit a non-specific one. A thorough history and examination are necessary to identify patella dislocation and its potential causes. Investigations should include cross-sectional imaging to evaluate both osseous and soft tissue structures in order to guide management. Management in the acute setting is normally non-operative, but damage to structural supports, osteochondral defects or recurrent dislocation should prompt consideration of operative treatment. Operative treatment should address the soft tissue stabilisers and/or osseus deformities that predispose to, or occur secondary to, patella dislocation.

Physeal injury in a skeletally immature male athlete

A 12-year-old skeletally immature male athlete presented for evaluation with acute bilateral knee pain. Initial radiographs revealed subtle lucency of the medial proximal tibial physis and MRI was recommended. On MRI, broad-based intravasation of the physis into the proximal femoral and tibial physes was observed. This represented physeal widening, a phenomenon that has been observed in skeletally immature athletes presenting for acute knee pain. While such changes to the physis may be quite prominent on MRI, conventional radiographic findings may be much more subtle. As many causes of chronic knee pain in this population are managed with active rehabilitation, a high index of suspicion for this diagnosis in the presence of physeal abnormalities may warrant evaluation with MRI. The literature suggests this pathology will resolve with rest, but, if weight-bearing activities are continued, there is a risk for significant growth abnormalities.