Key Points
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Essex-Lopresti injuries are frequently missed, therefore every proximal radius fracture requires at least a clinical and radiological examination of the elbow, forearm and wrist.
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In case of a clinical suspect Essex-Lopresti injury the recommended diagnostic tools to find or rule out an intraosseous membrane (IOM) rupture are either MRI or ultrasound (US).
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During proximal radius fracture surgery, forearm stability should always be examined by a combination of the radius push/pull test and Joystick test.
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An Essex-Lopresti injury should be preferably treated in the acute phase (< 4 weeks).
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Treatment of a chronic Essex-Lopresti injury should be assessed on a case-to-case basis.
Importance of the Problem
An ELI is a pattern injury that consist of a fracture of the proximal radius, disruption of the distal radial ulnar joint, and a rupture of the interosseous membrane (IOM) of the forearm. ELIs are rare and due to the predominant symptoms of a proximal radius fracture they are regularly missed or poorly treated. Most case series show a missed diagnosis frequency that exceeds 60%. In some cases longitudinal forearm instability due to a rupture of the interosseous membrane can be diagnosed acutely (< 4 weeks); however, it is more common that the interosseous membrane is partly ruptured causing progressing forearm instability over time.
A late treatment of an ELI is associated with a worse outcome for the patient. Patients who were treated in the acute phase showed an 80% success rate, well 80% of the patients treated for a chronic ELI demonstrated failure. Therefore it is crucial to know how to diagnose and treat ELIs in the acute phase.
Main Question
How can an Essex-Lopresti injury be diagnosed and what is the most effective management in the acute and chronic phase?
Current Opinion
ELI should be part of the differential diagnosis in every radial head fracture. Therefore, every radial head fracture requires a full radiological assessment of the elbow, forearm, and wrist. To diagnose subluxation or dislocation of the distal radioulnar joint (DRUJ) it is crucial to perform both a true posterior anterior as well as a true lateral view radiographs in neutral position. An additional radiograph of the wrist on the uninjured side enables assessment of the normal DRUJ variance. However, earlier studies found that radiographs alone are not reliable to either diagnose or rule out an ELI. Therefore, clinical examination is the most important indicator to decide if further investigation is required. A painful wrist and pain trough the forearm during clinical examination is the most important reason to perform additional radiologic examination. In the acute phase it is possible to detect an IOM injury by ultrasound (US) or magnetic resonance imaging (MRI). Furthermore, intraoperative examination can be performed to diagnose an IOM injury.
The IOM is known for having a low healing potential. Therefore, the golden standard treatment for acute or chronic ELIs has become surgical treatment. The treatment is focusing on restoring the radio-ulnar length and stabilizing the forearm. The acute treatment typically consists of either a replacement or fixation of the radial head in combination with pinning of the DRUJ. Depending on the grade of the distal instability, a TFCC repair could be considered. However, adding a TFCC repair to the procedure is more invasive and expensive compared to DRUJ pinning and should therefore be considered carefully. Chronic ELIs are treated by restoring the longitudinal stability between radius and ulna by reconstructive surgery. However, it is not clear what diagnostic tool and surgical technique is best to use to diagnose and treat an acute or chronic ELI.
Finding the Evidence
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Cochrane database: “Essex-Lopresti” 0; “Longitudinal forearm instability” 0; “Distal radio ulnar dislocation” 0; “Interosseous membrane” 0; “Interosseous ligament” 0.
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Pubmed (systematic review): “Essex-Lopresti” 1; “Longitudinal forearm instability” 0; “Distal radio ulnar dislocation” 0, “Interosseous membrane” 1; “Interosseous ligament” 2.
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Pubmed: “Essex-Lopresti” 231; “Longitudinal forearm instability” 62; “Distal radio ulnar dislocation” 152; interosseous membrane 594; Interosseous ligament 842.
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Articles that were not in English, French, or German were excluded.
Quality of Evidence
Level III:
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Systematic reviews of case series: 2
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Cadaveric case-control studies: 8
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Cohort studies: 7
Findings
Results for Diagnostic Tests
There were nine studies evaluating MRI, US, or intraoperative testing. Only two studies were comparative studies including one systematic review and one cadaveric study. Rodriguez-Martin and colleagues performed a systematic review of available publications and compared MRI with US. They concluded that, both US and MRI are equivalent in their capacity to diagnose IOM pathology. This is in line with the remaining four cadaveric studies that are evaluating US or MRI. These studies indicate sensitivities from 87.5% to 100%, specificity from 89% to 100%, and accuracy from 94% to 100% ( Table 1 ). Furthermore, one study found that a muscular herniation during dynamic US is a valuable predicter for a partial lesion of the IOM. According to these studies both MRI and US are reliable techniques to identify an IOM injury. As these studies were all performed using the interpretation of experienced musculoskeletal specialized radiologists, an experience bias should be considered for the interpretation of the results. To our best knowledge, there are no studies published focusing on the less specialized and experienced radiologists.
| Author | Imaging Modility | Specimens | Examiners | Sensitivity | Specificity | Accuracy | PPV | NPV | IOA |
|---|---|---|---|---|---|---|---|---|---|
| Fester | MRI | 38 | 3 | 93 | 100 | 96 | 91 | 100 | 1.0–0.79 |
| US | 19 | 3 | 100 | 89 | 94 | 89 | 91 | NA | |
| McGinley | MRI | 16 | 1 | 87.5 | 100 | 94 | 100 | 89 | NA |
| Jaakkola | US | 18 | 3 | NA | NA | 95 | NA | NA | NA |
| Soubeyrand | US a | 12 | 2 | 100 | 100 | 100 | 100 | 100 | 1.0 |
| Smith | Intraoperative b | 13 | NA | 83 | 83 | 83 | 83 | 83 | NA |
| Kachooei | Intraoperative c | 12 | 2 | 70 | 70 | 70 | 70 | 70 | 0.37 |
| Soubeyrand | Intraoperative d | 20 | 2 | 100 | 88 | 94 | 90 | 100 | 0.97 |
| Kachooei | Intraoperative d | 10 | 1 | 100 | 90 | NA | NA | NA | NA |
a Ultrasound with muscle herniation as a predictor.
b Using the push/pull test with longitudinal displacement of more than 3 mm.
c Using the Joystick test with increased lateral displacement without a cut off value.
d Using the Joystick test with lateral displacement with lateral displacement of more than 5.5 mm.
Another technique that is used to identify a possible lesion of the IOM is the intraoperative radial push/pull test or the Joystick test. The radial push/pull test focuses on the longitudinal displacement of the radius and the Joystick test is focusing on the lateral displacement of the radius in reference to the ulna. Four cadaveric studies reported on the intraoperative proximal radius push/pulling test. Most studies stated that a longitudinal displacement of the radius during the testing of > 3 mm during the radial push/pull test and a lateral displacement of the radius of more than 5.5 mm during the Joystick test is suggestive for an IOM rupture. Kachooei and colleagues found that the most reliable way to perform the Joystick test is by flexion the elbow in 90 degrees and maximal supination. However, the outcomes of these studies were varying a lot, possibly due to the difference in examining technique, examiner experience and cadaveric preparation ( Table 2 ).
| Author | Surgical Technique | Patients | Follow-Up (Months) | MEPS | MEWS | DASH | Morrey Score | Ext./Flex. (Wrist) | Ext./Flex. (Elbow) | Pron./Supin. | Complications |
|---|---|---|---|---|---|---|---|---|---|---|---|
| Grassmann | RHP + DRUJ pinning | 12 | 59 | 86.7 | 88.4 | 20.5 | NA | 50/50 | 8/138 | 75/81 | 4 × degeneration + heterotropic ossification |
| Trousdale | RHF | 1 | 120 | NA | NA | NA | Excellent | 60/60 | 30/125 | 40/80 | None |
| RHP + Darrach resection | 1 | 50 | NA | NA | NA | Good | 60/50 | 10/135 | 45/30 | None | |
| Edwards | RHF | 2 | 17 | NA | NA | NA | Excellent | NA | NA | NA | None |
| RHE | 1 | 30 | NA | NA | NA | Poor | NA | NA | NA | None | |
| RHP | 2 | 13 | NA | NA | NA | Excellent/good | NA | NA | NA | None | |
| Schnetzke | RHP + DRUJ pinning | 15 | 64 | 91.3 | 81.3 | 12.5 | NA | 54/63 | 11/130 | 68/68 | 2 × nerve palsy |
| Fontana | RHP | 1 | 16 | 83 | 88 | NA | NA | NA | NA | NA | Persistent wrist pain |
| RHP + IOMR | 1 | 15 | 95 | 95 | NA | NA | NA | NA | NA | None | |
| RHP + TFCC | 1 | 14 | 90 | 92 | NA | NA | NA | NA | NA | None | |
| RHP + IOMR + TFCC | 2 | 20 | 96 | 89.5 | NA | NA | NA | NA | NA | None | |
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