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HWN Suggests

How To Confidently Rule Out Traumatic Arthrotomy of the Knee

Traditionally, the saline loading test (SLT) has been a staple of investigation for possible traumatic arthrotomy. First described in the orthopedic literature in 1978, this test involves challenging the knee joint by injecting a significant amount of sterile saline into the joint space and observing for extrusion of saline from the wound(s).

Given the limitations of the saline loading test, are there additional diagnostic options? There is a small body of literature indicating that computerized tomography (CT) scanning of the knee joint may have a significant role in ruling out traumatic arthrotomies. One study found that CT scanning of the joint had superior performance to saline…

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Articles of Interest

Core EM

Mechanisms that should raise suspicion for violation of the joint capsule include penetrating trauma (knives, sharp objects, gunshot), falls, or other high energy injuries

Does the saline load test still have a role in the orthopaedic world? A systematic review of the literature

Several studies have demonstrated the utility of the SLT as a diagnostic modality for penetrating joint injuries. However, the literature analyzed in this study was inconclusive and more studies are required to make definitive recommendations.

Episode 80: Traumatic Arthrotomy

CT shows promise in diagnosing TA of the knee but not other joints. The saline load test (SLT) can be a sensitive test for identifying TA. However, it requires a significant volume of injected saline and is painful. Methylene blue is not necessary.

Open Breaks - Initial Management

Joint spaces may also be violated in open fractures, predisposing the patient to a septic joint. Traumatic arthrotomy should be considered when there is evidence of skin disruption near a joint. Large wounds in which the joint space is clearly visible virtually guarantees traumatic arthrotomy and requires emergent orthopedic consult.

Snap, Crackle, POP! Open joint: ED evaluation and management

Have a high index of suspicion for open joint injuries, especially near the knee which is the most common site. Saline load testing and methylene blue injection are no longer recommended for open joint evaluation. CT has highest sensitivity and specificity for open joint injury; look for air within the joint space.

Take a Knee…

But don’t I need to inject that blue stuff? A single study comparing injection of normal saline alone vs. methylene blue in patients undergoing routine knee arthroscopy showed instillation of methylene blue did not improve sensitivity in diagnosis of arthrotom

Traumatic Arthrotomy

Traumatic arthrotomy is defined as a soft tissue injury over a joint that penetrates the joint space. Violation of the joint capsule exposes the sterile intra-articular space to the environment which can result in a deep infection and sepsis. The morbidity associated with septic arthritis is high, so it is important that providers have a high index of suspicion when evaluating wounds over joint surfaces. The knee joint is the most common joint to be affected, followed by the ankle. Penetrating injuries have a higher rate of capsule violation so a history of knives or bullets should raise suspicion, though MVCs, falls, motorcycle accidents can also result in a deep injury. The capsule has little protection lateral to the patella, so even if the laceration does not appear deep there is potential that it penetrates the joint space.

Traumatic Arthrotomy with Pneumarthrosis on Plain Radiograph of the Knee

Even innocuous-looking lacerations adjacent to or overlying superficial joints can lead to a traumatic arthrotomy. Plain radiographs should be obtained and a high suspicion for intra-articular extension maintained. For lacerations around superficial joints there should be a low threshold for exploring and washing these wounds out in the operating room rather than closing primarily in the ED.