The assessment of acute knee injuries by Senior House Officers in the Accident and Emergency department

Ottawa Knee Rule: Investigating Use and Application in a Tertiary Teaching Hospital

Background

Knee injuries are encountered commonly in the emergency departments (EDs) in Ireland. Validated clinical decision rules such as Ottawa knee rule (OKR) can be used in acute knee injury settings to reduce the number of unnecessary radiography. Clinical judgment can be used to distinguish between suspected fractures and non-fractures in many cases; however, radiography is still routinely requested.

Objectives

We evaluated the OKRs in a high-volume tertiary teaching hospital in Ireland to determine whether the rule could be safely used to decide whether patients with acute blunt knee trauma should undergo radiography.

Methods

This was an observational study conducted in the ED over a three-month period in a tertiary referral hospital. A total of 110 patients with acute knee injuries were examined using OKR. Inclusion criteria included patients with acute knee injuries due to blunt trauma or twisting injury and patients with lacerations or contusions. Open fractures and fractures due to penetrating injury were excluded from the study.

Results

Fractures were seen in 12 (13.2%) of the 110 patents who met the inclusion criteria. The OKR predicted all 12 fractures. Sensitivity was 100%, and specificity was 39%.

Conclusions

The OKR is highly sensitive for fracture in this setting and can be safely used to decide whether patients with acute blunt knee trauma should undergo radiography.

Presentation, examination, investigation and early treatment of acute knee injuries

Acute knee injuries are common presentations that frequently occur during sporting activities and can result in permanent disability. However, they often result in a single visit, seldom receive surgical intervention and, in the main, are cared for entirely by General Practitioners or Emergency Department physicians. Thorough clinical assessment and appropriate early treatment at the primary presentation is vital in order to offer the best chance of maximal functional recovery and to minimize long-term disability. This requires a sound knowledge of basic knee anatomy, careful assessment of the mechanism of injury, detection and consideration of physical ndings and the results of adjunctive investigations. This article aims to give a comprehensive review of the examination, investigation and early treatment of acute knee injuries at the primary presentation. In addition, comments on important epidemiological and aetiological factors and a brief description of basic knee anatomy are also provided.

Can the Ottawa and Pittsburgh rules reduce requests for radiography in patients referred to acute knee clinics?

Our aim was to study the role of the Ottawa and Pittsburgh rules to reduce the unnecessary use of radiographs following knee injury. We prospectively reviewed 106 patients who were referred to our clinic over a 3-month period. The Ottawa and Pittsburgh rules were applied to individual patients to evaluate the need for radiography. One hundred and one patients (95%) had radiography of their knee. Five patients (5%) had a fracture of their knee and in all cases, the Ottawa and Pittsburgh knee rules were fulfilled. Using the Ottawa rules, 27 radiographs (25%) could have been avoided without missing a fracture. Using the Pittsburgh rules, 32 radiographs (30%) could have been avoided. The Ottawa and Pittsburgh rules have a high sensitivity for the detection of knee fractures. Their use can aid efficient clinical evaluation without adverse clinical outcome and may reduce healthcare costs.

The "sliver sign": a specific radiographic sign of acute lateral patellar dislocation

OBJECTIVE

The objective of this work is to assess the prevalence of the sliver sign, defined as an intraarticular linear or curvilinear ossific density, in association with knee effusion in patients with acute knee trauma, as a predictor of recent lateral patellar dislocation (LPD).

MATERIALS AND METHODS

A retrospective radiology database search for the term 'patellar dislocation' on MRI knee exams performed at our institution over a 7-year period identified 216 studies. Of these, 142 exams met true positive gold standard diagnostic criteria for LPD. Imaging findings of both the retrospectively identified radiographs and subsequent MRI were recorded. Accuracy of radiographic interpretation was also analyzed.

RESULTS

After review by an experienced musculoskeletal radiologist, 27 patients (19%) with LPD had knee radiographs demonstrating intraarticular osseous fragments. The majority of these patients had fragments (22/27, 81%) that were linear or curvilinear in configuration. A smaller subset of patients had fragments (5/27, 19%) that were rounded or oblong, felt to most likely represent sequelae of chronic dislocation. The fragments were identified on the patellar view only in eight of 27 patients (30%). These fragments were often initially misinterpreted, with the diagnosis explicitly stated in the report in 2/27 cases (7%). More often, the fractures were described vaguely (13/27, 48%), interpreted incorrectly (6/27, 22%), or missed (6/27, 22%). All 27 patients had moderate or large knee joint effusions.

CONCLUSIONS

In the setting of acute knee trauma, knee radiographs demonstrating a joint effusion and an intraarticular sliver-like osseous fragment correlate with recent lateral patellar dislocation. The routine trauma knee radiographic series does not include a patellar view but probably should, especially in young patients.

Management of soft tissue knee injuries in an accident and emergency department: the effect of the introduction of a physiotherapy practitioner

OBJECTIVE

To assess the effect of the introduction of a physiotherapist with an extended scope of practice in the management of acute soft tissue knee injuries in an accident and emergency (A&E) department.

METHODS

The A&E department established an Acute Knee Screening Service (AKSS) in 1998. An experienced physiotherapist was appointed to run the AKSS after additional training. Local guidelines and protocols were developed in conjunction with trauma knee surgeons, radiologists, physiotherapists, and A&E doctors. This study describes 100 consecutive patients managed by the AKSS over a three month period and comparisons are made over a similar period before the introduction of the AKSS.

RESULTS

The initial diagnosis of patients with acute knee injuries referred to the service showed meniscal injuries (38%), cruciate ligament injuries (18%), fractures (2%), patellofemoral joint injuries (10%), and others (32%). Ninety five per cent of patients referred to AKSS were seen within one week. Medical time was saved in both A&E and trauma clinic. Fifty nine per cent of patients were treated and discharged from the service without further medical review. Thirty nine per cent (39) were referred to trauma clinic and of these 44% (17) had MRI scans performed as requested by the physiotherapist. Eighty eight per cent (15) of these scans showed significant abnormality: (nine, anterior cruciate ligament tears, one, posterior cruciate ligament tears, and nine meniscal tears).

CONCLUSIONS

A physiotherapy practitioner working with an extended role is a valuable addition to an A&E department. The AKSS improves the quality of care of acute knee injuries, saves medical time, and fosters cooperation across services within the NHS.

The use of MRI scan of knee injuries in an emergency department

We present a retrospective study of the number of arthroscopically verified total meniscus and cruciate ligament tears seen in our Emergency department one year before, and one year after introducing magnetic resonance imaging (MRI) as a diagnostic tool. The number of total ruptures of the anterior cruciate ligament increased from 34 (1.7% of total 2003 patients) to 67 (2.9% of total 2277). The number of ruptures of the medial meniscus increased from 42 (2.1%) to 87 (3.8%). The number of ruptures of the lateral meniscus remained unchanged. In the first 12 months after introducing MRI we ordered 513 (23%) scans of the total number of 2277 patients with an acute knee condition. Thirty-nine (8%) of these were described with no pathology, 227 (44%) showed total meniscus or cruciate ligament tears. The remaining 247 (48%) were mainly degenerative or partial injuries. The cost per additional new diagnosis was approximately USD 800. The introduction of MRI has enabled us to identify a larger number of patients with meniscus and cruciate ligament injuries.

The clinical indications for plain radiography in acute knee trauma

OBJECTIVES

to assess the key symptoms and physical signs in the acutely injured knee that are significantly associated with fracture and utilise these to develop an algorithm for the use of radiography in acute knee trauma.

DESIGN

retrospective review of all acute knee injuries presenting to the accident and emergency unit at a District General Hospital over a 6-month period in 1998 (over 500 cases). After exclusions, a study group of 370 eligible adults was obtained. These patients were reviewed for the key symptoms and physical signs, and radiological evidence of fracture.

OUTCOME MEASURES

the X-ray films were interpreted by a consultant radiologist. Of those patients on whom radiographs were not performed, follow up was assessed by a review of any re-attendance to the A&E department.

RESULTS

there was a statistically significant correlation, using chi-square (Mantel-Haentzel) and linear regression analysis, between the presence of a fracture and each of the following variables: age, non-weightbearing in the department (p<0.05), haemarthrosis, point bony tenderness, effusion (p<0.001).

CONCLUSION

these key symptoms and physical signs may form the basis of an algorithm for examining knees radiologically, with acceptable positive and negative predictive values. (This is currently being tested prospectively).