Orthopedics

High risk and low prevalence diseases: Traumatic arthrotomy

a b s t r a c t

Introduction: Traumatic arthrotomy (TA) is a rare but Serious condition associated with a high morbidity and mortality that can be mitigated with Prompt diagnosis and appropriate management.

Objective: This review highlights the pearls and pitfalls of the emergency department (ED) evaluation of TA, including Diagnostic procedures, imaging, and management based on current evidence.

Discussion: Traumatic arthrotomy occurs when the joint capsule is disrupted during a penetrating injury. This ex- poses the intra-articular contents to contamination and poses a serious risk for development of Septic arthritis. All periarticular injuries should prompt evaluation for TA, as missing this diagnosis can lead to significant morbidity and possibly mortality. ED evaluation options include plain radiographs, computerized tomography, and the sa- line load test. Each of these diagnostic modalities has unique limitations, and as such it is difficult to determine optimal practice or a standard of care. This is further complicated by the limited number of studies evaluating joints other than the knee. ED management includes orthopedic surgery consultation, wound care including irrigation, tetanus prophylaxis, and antibiotic administration.

Conclusions: An understanding of an evidenced-based approach to TA can assist emergency clinicians in diagnosing and managing this challenging clinical presentation.

Published by Elsevier Inc.

Introduction

This article series addresses high risk and low prevalence diseases that are encountered in the emergency department (ED). Much of the primary literature evaluating these conditions is not emergency medi- cine focused. By their very nature, many of these Disease states and clin- ical presentations have little useful evidence available to guide the emergency physician in diagnosis and management. The format of each article defines the disease or clinical presentation to be reviewed, provides an overview of the extent of what we currently understand, and finally discusses pearls and pitfalls using a question-and-answer format. This article will discuss traumatic arthrotomy. This condition’s low prevalence but high morbidity and mortality, as well as its variable atypical Patient presentations and challenging diagnosis, makes it a high risk and low prevalence disease.

1. Definition

Traumatic arthrotomy (TA) occurs when a periarticular laceration disrupts the joint capsule and exposes the intra-articular surface to

* Corresponding author at: 3841 Roger Brooke Dr, Fort Sam Houston, TX 78234, USA.

E-mail addresses: [email protected] (H.G. Colmer), [email protected] (B. Long).

contamination (Fig. 1). TA occurs most commonly in mid twenty- to early thirty-year-old men [1-3]. The mechanism of injury is variable with motor vehicle accidents and gunshot wounds accounting for the majority of presentations. The knee is the most commonly affected joint accounting for 53 to 91% of all TA presenta- tions, but TA can occur at any joint including the shoulder, elbow, wrist, hip, and ankle, as well as the smaller joints of the hands and feet [1-3].

TA places the patient at risk for development of septic arthritis and is considered an emergent surgical condition [3,4]. Septic arthri- tis has a reported mortality rate as high as 15% and an irreversible decrease in joint function rate between 25 and 50% [5]. With con- tinued improvements in the approach to the diagnosis and treat- ment of TA, rates of septic arthritis have improved from 100% in the earliest reports to less than 5% in more recent studies [4,6-9]. functional outcomes are most closely correlated with the extent of soft tissue and osseous injury, with one study also reporting an as- sociation between delayed debridement and worse pain, limp, range of motion, Joint instability, and crepitus [1,3,10]. Periarticular lacera- tions that have not violated the joint capsule can be managed with standard wound care by an emergency clinician; however, failure to appropriately recognize TA can result in significant morbidity and mortality.

https://doi.org/10.1016/j.ajem.2022.01.013 0735-6757/Published by Elsevier Inc.

Fig. 1. Joint anatomy. Obtained from https://commons.wikimedia.org/wiki/File:907_ Synovial_Joints.jpg

Discussion
1. Emergency department presentation

The presentation of TA can vary significantly involving patients from all stages of life, a variety of traumatic mechanisms, and any joint. How- ever, the most common presentation involves a young male patient who has sustained trauma to the knee after a motor vehicle collision or GSW [1-3]. Based upon the severity of trauma and other Associated injuries, the patient may present with hemodynamic instability. Pa- tients will typically complain of pain at the affected joint; however, distracting injuries may obscure this. Although not commonly used, Col- lins and Temple published a classification system for open joint injuries which ranges from Grade I (a single capsular perforation or laceration without extensive soft-tissue injury) to Grade IV (an open dislocation or associated nerve or Vascular injury requiring repair) [3]. Using this classification system, a Grade IV injury would be readily apparent; how- ever, a Grade I injury could be easily missed and mistaken for a superfi- cial laceration. Much of this article will attempt to provide an approach to a high risk wound where TA is not apparent but cannot be ruled out simply based on inspection of the wound.

1. Emergency department evaluation

A thorough history and physical examination play an important role in the evaluation of TA. Identification of a mechanism that could result in a penetrating injury or an examination that identifies even a small periarticular laceration is the first step in raising the suspicion for TA [4]. The physical examination should first focus on identifying immedi- ate life-threatening injuries. Once stabilized, the neurovascular status of the affected joint should be assessed. Only once the patient is stabilized and the limb does not show signs of neurovascular compromise should the emergency clinician continue with the evaluation for TA. Laboratory testing plays no significant role in the evaluation for TA. Initial imaging should involve plain radiographs of the affected joint. Visualization of a fracture, intra-articular Free air, or radiopaque foreign objects are highly suspicious for TA [4]. Emerging evidence supports the use of computed

tomography (CT) to evaluate for TA of the knee, although this does not appear to be standard of care at this time [8,11,12]. The saline load test (SLT) can also be used to further evaluate the integrity of the joint cap- sule by injecting sterile saline into the joint away from the location of the traumatic wound and observing for fluid efflux from the wound [4,13].

1. Emergency department management

The ED management of TA begins with a complete trauma evalua- tion including primary and secondary surveys with resuscitation efforts then directed primarily to those injuries that are immediately life- threatening. Following stabilization, early orthopedic consultation is recommended for consideration of joint exploration with irrigation and debridement. While awaiting or in conjunction with the orthopedic evaluation, the joint should be immobilized, and the patient should re- ceive tetanus prophylaxis and antibiotics. Focused wound care with irri- gation should be performed for injuries, especially for grossly contaminated wounds.

Pearls and Pitfalls
1. What is the utility, as well as limitations, of the history and examination in a patient with suspected traumatic arthrotomy?

The history can provide valuable information concerning mecha- nism, possible contaminants, and risk factors for development of infec- tion; however, there is no specific historical component that can confirm or exclude the diagnosis. As part of their study comparing the SLT to clinical judgement, Voit et al. reported clinical judgement alone to have a sensitivity of 57% and specificity of 61% in diagnosing TA [14]. The history is limited in the setting of other associated traumatic injuries such as those that cause direct alterations in mental status or a distracting injury. When possible, exploring in detail the mechanism of the injury is important when the laceration is not directly overlying the joint. In such instances, understanding the trajectory of penetrating objects and logical consideration of the possible injured structures is critical to avoid missing a wound with a deep tract leading to the joint [4].

Physical examination can confirm the diagnosis with direct visuali- zation of joint capsule disruption. Findings highly suspicious of TA in- clude fat droplets in the blood and extravasation of synovial fluid at the injury site [4]. A sterile cotton swab can be used after local anesthe- sia is provided to probe the depth of the wound. We recommend using local infiltration of an anesthetic (e.g., lidocaine with or without epi- nephrine) to achieve anesthesia without entering the joint capsule when evaluating wound depth. In the setting of smaller lacerations without any of the above findings, physical examination is limited in confirming or excluding the diagnosis of TA [3,4]. Ultimately, neither history nor physical examination can be used to definitively exclude TA in a high risk wound.

1. Is a plain radiograph or ultrasound useful in diagnosis, and if so, what are the limitations?

Plain radiographs are routinely ordered in the evaluation of a trau- matic joint injury to evaluate for underlying fracture or dislocation [4]. Sleasman et al. retrospectively evaluated the utility of conventional ra- diographs in the detection of TA of the knee and found a sensitivity of 78.1% and specificity of 90.6% to evaluate for free air within the joint space [15]. Of note, 80% of the knee radiographs that were retrospec- tively identified to have free air were missed on initial radiology inter- pretation. The authors posit that without being primed to evaluate for intra-articular air, this finding is likely to be missed, and they recom- mend communicating the concern for TA to the radiologist prior to obtaining the radiograph [15]. Another study designed to evaluate the

role of CT in detecting TA of the knee found that 47% of TAs could be de- tected on plain radiograph alone [11].

One cadaveric study has evaluated the utility of ultrasound in the de- tection of TA of the knee and found a sensitivity of 65% and specificity of 75% [16]. The authors concluded that this was not sufficient to recom- mend routine use of ultrasound in the evaluation of TA, and further study is warranted.

Based on the current available literature, Plain radiography appears to be helpful when there is intra-articular gas or foreign body, but it is not sufficient to exclude a diagnosis of TA if normal [15]. Ultrasound re- quires further study before being used in the evaluation of TA [16].

1. What are the indications for the saline load test (SLT), how is it com- pleted, and what are the limitations?

The saline load test (SLT) was first described by Patzakis et al. in 1975 and until recently has been considered the gold standard in bedside evaluation for TA [1,4,13]. The SLT involves injection of sterile saline into the joint space at an insertion site distant from the traumatic wound and observing for fluid efflux from the wound [4]. Local anes- thetic (e.g., lidocaine with or without epinephrine) can also be injected into the joint space to assist with pain control when performing the SLT. A 1996 study found that SLT changed management in 40% of pa- tients with TA compared to clinical judgement alone [14]. There are mul- tiple studies supporting its use for various joints, which will be discussed in further detail [17-29]. However, there are significant issues with the SLT including poor patient tolerance due to the high volume of injected fluid required to achieve an adequate sensitivity, risk of “operator error” leading to a false negative result, and the potential role of the much less painful and noninvasive imaging with CT [4,13]. Examples of “operator error” include failure to enter the joint capsule prior to injection of saline, insufficient volume of saline injected, and failure to detect extravasation from the wound when present. Procedural sedation can be considered to facilitate patient tolerance of the required high injection volumes. Pa- tients with significant trauma are often not ideal candidates for proce- dural sedation, which limits the utility of the SLT in these patients.

It has been previously suggested that the addition of Methylene blue to the saline injection solution could increase the sensitivity of SLT. However, two studies found no increase in sensitivity of the SLT with the addition of methylene blue [26,30].

Knee

The knee is the most studied joint for the use of the SLT for diagnosis of TA. Volume of injection appears to play a significant role in the sensi- tivity of the SLT within the knee. Studies where low volumes (50-60 mL) were injected have reported sensitivities of 36% to 46% [22,31]. Studies using higher volumes (75-194 mL) found sensitivities of 94% and 95% [22,25,32]. One study evaluated the effect of dynamic range of motion during the SLT and found an increase in sensitivity from 36% to 43% at volumes of 60 mL [31].

Elbow

There is also a suggestion that higher volumes of injected saline can improve sensitivity at the elbow. Two studies documentED volumes of injections and reported a sensitivity of at least 95% with volumes be- tween 19 and 40 mL [21,24]. Feathers et al. reported a volume of 40 mL to achieve a sensitivity of 95% [24]. Lower volumes at 20 mL only achieved a sensitivity of 72%, but they did find an improvement with dy- namic range of motion to 86% [24].

Wrist

Three studies comment on injection volume for SLT at the wrist [14,17,23]. They reported injection volumes between 2.3 and 7 mL to achieve a sensitivity greater than 95%. Gittings et al. found an increase in sensitivity with increasing volume [23]. There have been no reports on modification with dynamic range of motion.

Ankle

Four studies comment on injection volume for SLT at the ankle [18,20,26,28]. There is much greater variability among the reported

results compared to other joints, with volumes required to achieve a sensitivity of at least 95% being between 10 mL and 55 mL. Among those studies that reported varying injection volumes, there was a trend towards increased sensitivity with increasing volume [18,20,28]. No study reported using dynamic range of motion.

Shoulder

There is a single study that has evaluated the efficacy of the SLT at the shoulder [29]. This study found an injection volume of 81 mL was necessary to achieve a sensitivity of 95%. Dynamic range of motion was not evaluated, but it found an increase in sensitivity with increasing volume [29].

Hip

There are no studies available that discuss the use of SLT at the hip.

Pediatrics

The pediatric literature is more limited and primarily relies on case reports and extrapolation from the adult literature for the management of TA [33]. One study reports a 47 mL injection volume to achieve a 90% sensitivity in pediatric knees [27]. Additionally, it reported a significant correlation between injection load volume and age, height, weight, and body mass index (BMI) [27]. Given the paucity of high-quality data, it would be prudent for the emergency clinician faced with a possible TA in a child to immobilize the injury and seek consultation early.

Summary

The available evidence supports SLT achieving sensitivities approxi- mating 95% in diagnosing TA of the knee, elbow, wrist, and shoulder in adults. However, to achieve these sensitivities, a large volume of saline must be injected, which may be intolerable for patients [14,17,18,20, 21,23-26,28,29,32]. Rather than targeting a specific injection volume, it is often recommended that a volume of saline sufficient to visibly distend the joint be used and then titrated to patient tolerance [4,13]. However, injection of volumes of fluid sufficient to reach adequate sen- sitivity will almost universally be painful for patients. If the patient is not able to tolerate a large volume of injection, the procedure will be in- conclusive.

Table 1 presents the reported SLT injection volumes to achieve a sen- sitivity of 95%, as well as the volume of fluid that could occupy the space of the typical joint if it were filled. Exceeding these volumes results in joint distension and likely significant pain. It is useful for an emergency clinician to know these volumes when attempting to interpret the result of their SLT relative to the amount of volume they were able to success- fully inject.

The addition of dynamic range of motion during the SLT has not been extensively studied but does have some evidence to support its use [24,31]. In circumstances where the SLT is negative at maximal tolerated injection volume, adding dynamic range of motion may help detect an otherwise occult TA via expression of injected saline from the wound, though more research is necessary prior to formalizing this recommen- dation. There is no evidence supporting the addition of methylene blue [26,30].

1. When should computed tomography be used, and what are the limita- tions of this imaging modality?

CT has been proposed as an alternate and perhaps preferred modal- ity in the evaluation for TA [4,13,15]. Intra-articular air is the primary

Table 1

Average SLT injection volumes to achieve 95% sensitivity [14,17,18,20-26,28,29].

Joint	Average joint volume	SLT injection volume to achieve sensitivity of
	(mL)	95% (mL)
Knee	131 +- 53	155-194
Elbow	35.8 +- 11.36	19-40
Wrist	1.34 +- 0.34	2.3-7
Ankle	20.9 +- 4.9	10-55
Shoulder	21.1 +- 7	81
Hip	33.2 +- 12.58	N/A

studied abnormality on CT suggestive of TA, but the presence of a for- eign body and periarticular fracture are other associated findings [11]. Konda et al. published a series of papers in 2013 describing the efficacy of CT for identifying free air in the knee for the purposes of diagnosing

Table 3

antibiotic recommendations for TA.

Patient factors Antibiotic recommendation

Standard prophylactic coverage 1st generation cephalosporin (e.g., cefazolin)

TA [8,11,12]. They first reported that CT was able to detect volumes of air as low as 0.1 mL when injected into the knees of cadavers with

Significant soft tissue injury or contamination

Add gram negative coverage (e.g., piperacillin/tazobactam)^a

100% sensitivity and specificity [12]. They reported CT had a sensitivity of 100% in diagnosing TA in patients when they used capsular disruption on surgical evaluation or development of septic arthritis as their end- points [8]. Lastly, they also reported that the addition of CT during the evaluation of knee trauma altered management in 43% of patients dis- covered to have a periarticular fracture [11].

A major limitation in the available evidence supporting the use of CT in diagnosing TA is that it primarily focuses on the knee. A smaller study by Kupchick et al. compared the use of SLT to CT in the diagnosis of TA of the elbow [19]. To accomplish this, they used ten cadavers with surgi- cally generated arthrotomies and found CT to identify 0% of TA in com- parison to SLT which identified 100%. There is also a case report of a patient with traumatic elbow arthrotomy after a motor vehicle accident that was not diagnosed on plain radiograph or CT. This patient returned two weeks later with purulent septic arthritis [34]. No other joints have been evaluated in the literature.

In summary, CT shows promise as an adjunct in the diagnosis of TA especially in relation to evaluation of periarticular knee wounds. Cau- tion is recommended when attempting to apply these findings to other joints until more research has been conducted. There are some unique physiologic circumstances under which CT can produce a false positive due to the appearance of air in the joint; however, these would not be nearly as consequential to the emergency clinician as a false negative test [35,36]. Compared to SLT, CT has the benefit of being less invasive and less dependent on the skill of a proceduralist but comes with the downside of involving radiation and being more costly. As of now CT is most helpful when positive for intra-articular air prompting more aggressive management of suspected TA, but emer- gency clinicians should be cautious in excluding TA based only on a neg- ative CT. It does not appear that CT scan for TA has a role in joints other than the knee at this time.

1. Which antibiotics should be utilized?

There are no studies directly evaluating appropriate antibiotic cover- age for patients with TA. Studies have confirmed that systemic prophy- laxis is appropriate, as antibiotic concentrations closely correlate with synovial concentrations [37,38]. Classical teaching is to provide antibi- otics that cover for streptococci and staphylococci, though no specific antibiotic guidelines have been proposed [4].

Most of the proposed antibiotic regimens are adopted from guide- lines surrounding the management of Open fractures [4,39,40]. Avail- able guidelines recommend determining antibiotic coverage based upon Gustilo-Anderson classification for open fractures (Table 2) [40]. Studies have shown an increased infection rate with more severe Gustilo-Anderson classification grades [41]. As an example, The Eastern Association for the Surgery of Trauma (EAST) trauma guidelines on open fractures recommend gram positive coverage for all Gustilo-

Table 2

Gustilo-Anderson classification [40,41]. Type Characteristics

- 1. Puncture wound <1 cm, minimal contamination and soft tissue damage
  2. Laceration >1 cm but <10 cm, moderate soft tissue damage, adequate bone coverage, minimal comminution

IIIA Laceration >10 cm, extensive soft tissue damage, adequate bone coverage, segmental/severely comminuted fractures or heavily contaminated wounds

IIIB Similar to Gustilo type IIIA injury but with periosteal stripping and bone exposure

IIIC Any open fracture with vascular injury requiring repair

MRSA risk factors Linezolid or vancomycin Seawater contamination Ceftriaxone plus doxycycline

^a gentamicin may be considered.

Anderson Grade I and II fractures and adding gram negative coverage for Grade III fractures [40].

Attributable in part to the use of prophylactic antibiotics, rates of in- fection have declined substantially from the earliest reports describing TA [1,2,4,7,8,11,42]. Given the paucity of data to guide antibiotic selec- tion, Table 3 serves to provide antibiotic recommendations for prophy- laxis in TA.

Antibiotics play a significant role in the management of TA, and al- though there are no clear guidelines for the timing, dose, or selection of antibiotics, appropriate coverage can be inferred from the current available literature and management of open fractures. For most pa- tients with an identified TA, a first-generation cephalosporin such as cefazolin provides adequate prophylactic coverage for staphylococcal and Streptococcal species [1,7,9,42]. In more severe injuries with exten- sive soft tissue injury, the addition of gram-negative coverage with an extended spectrum penicillin such as piperacillin/tazobactam or genta- micin is recommended [4,7,40]. Additionally, patient and contaminant specific factors should be considered. If the patient has significant risk factors for methicillin resistant Staphylococcus aureus (MRSA), an agent such as linezolid or vancomycin is recommended. Contamination with seawater should prompt consideration of adding a third- generation cephalosporin such as ceftriaxone plus doxycycline to cover against Vibrio vulnificus [43].

Table 4 provides pearls in the evaluation and management of TA.

Conclusions

The evaluation of suspected TA remains a unique challenge facing emergency clinicians. There can be a wide array of presentations rang- ing from a small, isolated periarticular laceration to a hemodynamically unstable patient who presents with polytrauma. Plain radiographs can show intra-articular free air, foreign body, or a periarticular fracture, which are all highly suggestive of TA. The SLT is a bedside procedure that can be performed to further assess for TA; however, achieving reli- able sensitivities requires a significant volume of saline be injected into the joint, which often is not well tolerated by patients. Emerging evi- dence is arising regarding the use of CT to evaluate for intra-articular free air for the diagnosis of TA. While promising in regards to TA of the knee, there is limited or conflicting evidence surrounding its use

Table 4

Traumatic arthropathy pearls.

Traumatic arthrotomy (TA) can lead to significant morbidity and mortality when missed. Discuss the case with orthopedic surgery in patients with high risk wounds.
Plain radiographs can suggest the presence of TA when free air is seen within the joint space. Consider communicating the concern for TA to the radiologist prior to obtaining the radiograph.
The saline load test (SLT) can be a sensitive test for identifying TA; however, it requires a significant volume of injected saline that is often intolerable to patients. There is no evidence to support the addition of methylene blue to the saline injection solution.
Computed tomography (CT) shows promise in diagnosing TA of the knee. Caution should be used when applying CT to other joints.
Antibiotics should be administered to all suspected cases of TA. A first-generation cephalosporin such as cefazolin is reasonable for most presentations. Consider adding gram negative coverage for more severe or contaminated injuries.

with other joints. Regardless of which modality is chosen to evaluate for TA, caution is required in interpreting a negative result. ED management centers around rapid orthopedic surgery consultation, appropriate wound care including irrigation of the wound, tetanus prophylaxis, and administration of antibiotics. An understanding of the utility and limitations of the available diagnostic and management options is es- sential in optimizing patient outcomes. Ultimately, the emergency clini- cian must consider TA when evaluating all periarticular lacerations, as missing this diagnosis can result in significant morbidity and mortality.

CRediT authorship contribution statement

Henry Gerard Colmer: Writing – review & editing, Writing – origi- nal draft, Conceptualization. Matthew Pirotte: Writing – review & editing, Writing – original draft, Supervision. Alex Koyfman: Writing – review & editing, Supervision. Brit Long: Writing – review & editing, Writing – original draft, Supervision.

Declaration of Competing Interest

None.

Acknowledgements

BL, AK, GC, MP conceived the idea for this manuscript and contrib- uted substantially to the writing and editing of the review. This manu- script did not utilize any grants, and it has not been presented in abstract form. This clinical review has not been published, it is not under consideration for publication elsewhere, its publication is approved by all authors and tacitly or explicitly by the responsible authorities where the work was carried out, and that, if accepted, it will not be published elsewhere in the same form, in English or in any other language, includ- ing electronically without the written consent of the copyright-holder. This review does not reflect the views or opinions of the U.S. Govern- ment, Department of Defense, U.S. Army, U.S. Air Force, or SAUSHEC EM Residency Program.

References

AJEM

High risk and low prevalence diseases: Traumatic arthrotomy

a b s t r a c t

Leave a Reply Cancel reply