Complexe voetletsels worden tijdens de acute presentatie vaak gemist met als gevolg uitgestelde behandelingen en slechtere uitkomst. De mogelijkheden en toepassing van verschillende diagnostische modaliteiten is vaak per ziekenhuis verschillend. Het is onduidelijk wat de beste diagnostiek is om in te zetten en wat de indicaties hiervoor zijn. Hierbij kan men denken aan een CT of MRI scan maar ook aan een aanvullende belaste voetfoto die niet in alle ziekenhuizen standaard gemaakt worden.

Eight studies were found that compared diagnoses based on (primary) radiographs with diagnoses based on CT or MRI. As there was no comparison with surgical findings (reference), these studies did not comply with the PICRO. However, the guideline development group evaluated these studies to be relevant for answering the question: What is the diagnostic accuracy of an additional CT/MRI, compared to a (non-weightbearing) foot x-ray only in patients with suspected traumatic foot injuries (talus, calcaneus, Chopart or Lisfranc)?

Description of studies and results

Chopart injuries

Almeida (2018) retrospectively reviewed the radiology database to assess the sensitivity of weight bearing (WB) and non-WB radiographs for Chopart fractures, and to assess the sensitivity of radiographs (WB and non-WB) to detect additional fractures. The radiology database was queried for radiology reports on Chopart fractures. Inclusion criteria were: diagnosis of Chopart fracture and imaging work-up including at least one radiograph (WB or non-WB) and subsequent cross-sectional image (CT or MRI). In total, radiographs of 108 patients met the inclusion criteria. Mean age of these patients was 46.4 years, and 67.6% was male. High energy trauma mechanisms were reported in 55.6% of the patients. Chopart injury diagnoses that were made based on the WB and non-WB radiographs (index test) were compared to diagnoses based upon the CT or MRI (reference test). The indications for either a WB or non-WB radiograph were not reported. A diagnosis of Chopart fracture was based on the following criteria: presence of a radiology report (radiograph, CT, or MRI) showing a midfoot fracture extending to the calcaneocuboid or talonavicular joints and documentation of conservative or surgical treatment. The number of correct Chopart fracture diagnoses by radiography were reported. Additionally, the number of additional fractures detected by either radiography or CT/MRI were compared. Patients were treated conservatively or surgically.

Hirschman (2018) performed a retrospective analysis to assess the frequency of concomitant injuries at the calcaneocuboid and talonavicular joint (indicating advanced Chopart injury) using radiography and MRI and to correlate these findings with radiologic and clinical diagnoses. A hospital database search was performed to identify adult patients (> 18 years), with both radiographs and MRI of the ankle and foot. Inclusion criteria were: patients with evidence of fractures in the anterior process of calcaneus on radiographs, MRI or both; a time interval up to 8 weeks between radiography and MRI and imaging within 8 weeks of acute ankle injury. The study population consisted of 21 patients, mean age 51.7 ± 13 years, 19% male. Radiographs (index test) and MRI (reference test) were compared. Indications for both radiography and MRI were twisting ankle injuries from missing a step (n = 7), nonspecific ankle injury (n = 6), sports-related ankle injury (n = 5) and ankle injury after a fall (n = 3). All radiographs and MRI’s were retrospectively reviewed in consensus by two musculoskeletal radiologists. An injury was defined on radiographs as an avulsion fracture and om MR images as bone marrow edema, avulsion fracture or ligamentous sprain. The term ‘equivocal’ was used when both consensus readers were unsure whether an injury was present. All patients were treated conservatively.

Almeida (2018) and Hirschmann (2018) presented the following data on Chopart injuries detected by (primary) radiographs, when compared with CT and/or MRI, see Table 1. The data should be interpreted carefully due the retrospective nature of the studies and the lack of data on patients not undergoing CT and/or MRI (true negatives and false positives).

Table 1: studies reporting data on Chopart injuries detected by (primary) radiographs, when compared with CT/MRI

CT = Computer Tomogrpahy, MRI = magnetic resonance imaging, TP = true positives, FN = false negatives, TN = true negatives, FP = false positives, Sens = sensitivity, Spec = specificity

Lisfranc injuries

Haapamaki (2004)-2 performed a retrospective study to assess the acute phase multidetector computed tomography (MDCT) findings of Lisfranc fracture-dislocations. The hospital database of a level-1 trauma centre was reviewed for acute or serious foot or ankle injuries who had MDCT of the foot and ankle. In total, 282 patients were identified, mean age 42 years (range 13 to 89), 73% male. Of these patients, 19 patients had a Lisfranc fracture dislocation. Primary radiographs (index test), when available, were compared with MDCT findings (reference test). Foot and ankle MDCT were requested by emergency room physicians for clinical reasons, mainly to reveal complex fracture anatomy in patients with multiple injuries. In this centre, MDCT was routinely used for screening seriously injured patients. Radiographs of the foot were done routinely on all patients before the foot and ankle MDCT. For two patients a primary film radiograph was not available, as these patients were immediately scanned with MDCT because of multiple injuries to the lower limbs and body. Data of these patients was excluded from the analysis. All patients were treated operatively, except one. This patient was assigned to non-operative treatment because of serious head injury.

Ponkilainen (2019) retrospectively analyzed foot- and ankle scans to assess the diagnostic parameters of non-weight bearing foot radiographs compared with CT in Lisfranc injuries. CT and Cone Beam Computertomography (CBCT) scans acquired due to acute foot trauma at a university hospital and a regional hospital were reviewed. Scans with a diagnosis of Lisfranc Injuries were included. Lisfranc injuries were defined as intra-articular fractures and avulsion fractures around the TMT-joint. Patients with extra-articular metatarsal fractures were excluded. A sample of 100 patients was included, of which 34 patients had no Lisfranc injury (some had distal foot fractures), 33 patients with a non-displaced Lisfranc injury, and 33 patients with a displaced Lisfranc. Mean age of the study population was 40.9 ± 18 years, 55 % male. It was not described what the indications were to perform a CT. CT-scans (reference test) were separately evaluated by two experienced foot surgery experts. The anonymized primary non-weight bearing radiographs (index test) were assessed independently by three orthopaedic surgeons, and three orthopaedic surgery residents, twice at three months. They were asked if, based on the radiographs, there was an injury present in the Lisfranc Joint, and if there were other injuries present. False positive rates were calculated by dividing the false negative cases with the CT-positive cases. False negative rates were calculated by dividing the false positive cases with the CT-negative cases.

Preidler (1999) performed a prospective study to compare the diagnostic capabilities of conventional radiography, CT and MRI imaging in depicting ligamentous and bony changes and joint malalignment in patients after hyperflexion injuries. Patients presenting with acute hyperflexion injuries were included in the study (n = 49). Mean age of the study population was 41 years, 55% male. Conventional and weight bearing radiographs were obtained on the day of the injury. All patients underwent CT examination within 48 hours. Additionally, patients underwent MRI, between 18 hours and 5 days after the trauma. All CT- and MRI- scans were masked before being reviewed. Two radiologists independently reviewed the radiographs, CT- and MRI-scans. Eleven patients who presented with joint malalignment on CT and/or MRI underwent surgery (which was considered the gold standard). Five other patients with joint malalignment on CT and/or MRI refused surgery and underwent conservative treatment. All other patients, without signs of instability, were also treated conservatively. As an outcome it was reviewed whether the radiographs, CT and MRI images showed joint malalignment or not.

Rankine (2012) retrospectively analysed hospital data to calculate the diagnostic accuracy of radiographs in the diagnosis of Lisfranc injury using CT and surgical findings as reference standard. A hospital database was searched for patients who underwent CT of the foot for the investigation of acute foot injury. In total, 60 patients were identified, mean age 37 ± 16.7 years, 55% male. Radiographs (index test) and CT (reference test) were compared. If primary radiographs showed evidence of Lisfranc injury or when patients had normal radiographs but with clinical suspicion of significant foot injury, patients underwent additional CT. The initial presenting radiographs were evaluated independently by two experienced consultant radiologists. One of the observers evaluated the CT examination while blinded to the radiographic evaluation. Malalignment of the tarsal-metatarsal joints (using standard criteria), with particular attention paid to the second metatarsal, was evaluated as evidence for Lisfranc Injury. Presence of intraarticular fractures of the bases of the metatarsals involving the tarsal-metatarsal joint was also taken as evidence of Lisfranc injury. Subtle capsular avulsions involving the tarsal-metatarsal joint were taken as evidence of potential Lisfranc Injury. Patients either received conservative treatment with plaster immobilization, examination under anaesthesia without surgical fixation if no instability was found on stress testing and open reduction and internal fixation in the presence of instability.

Haapamaki (2004)-2, Ponkilainen (2019), Preidler (1999) and Rankine (2012), presented the following data on Lisfranc injuries detected by (primary) radiographs, when compared with CT/MRI, see Table 2. The data should be interpreted carefully due the retrospective nature of the studies and the lack of data on patients not undergoing CT and/or MRI (true negatives and false positives).

Table 2: studies reporting data on Lisfranc injuries detected by (primary) radiographs, when compared with CT/MRI

CT = Computer Tomography, MRI = magnetic resonance imaging, TP = true positives, FN = false negatives, TN = true negatives, FP = false positives, Sens = sensitivity, Spec = specificity

Talus fractures

Haapamaki (2004) performed a retrospective study to assess multidetector computed tomography (MDCT) findings and the advantages of MDCT compared with radiography for diagnostic evaluation of acute ankle and foot trauma. The hospital database of a level-1 trauma centre was reviewed for patients with an acute foot or ankle injury and who underwent MDCT. In total, 388 patients with 517 fractures were identified, mean age was 40 years (range 16 – 89), 73% male. Primary radiographs (index test) were compared with MDCT findings (reference test) of the ankle and foot. The diagnosis of acute traumatic ankle or foot fracture was based on MDCT, which was regarded as the gold standard in this study. The ankle and foot MDCT examinations were requested by emergency department physicians mainly to reveal complex fracture anatomy or to rule out a fracture. The radiographs were reevaluated by consensus. Of the 388 eligible patients, primary radiographs and MDCT findings were available for 296 patients with fractures. Based on the MDCT findings, 73 patients were diagnosed with talar fractures and 187 patients were diagnosed with calcaneus fractures. The number of patients treated surgically was 37 (51%) and 107 (57%) respectively. It was reported that 13 patients had luxations of the Chopart joint, however data on the diagnostic accuracy of radiographs for this type of injury was not presented. Data on the diagnostic accuracy of primary radiographs for Lisfranc injury were presented in a separate publication (Haapamaki, 2004-2). There were 44 patients with negative MDCT findings.

Dale (2013) reviewed a level-1 trauma centre database to describe talar fracture patterns and associated injuries using both radiography and CT. Radiology and clinical data of patients diagnosed with acute talar fractures were retrospectively reviewed. In total, 132 fractures were identified (122 patients, 10 with bilateral injuries), of which 120 were imaged with both CT and radiography. Mean age of the study population was 41 years (range 18 – 81 years), 73% of the patients were male. Mean Injury Severity Score (ISS) was 16 (range 4- 57).

In patients who underwent both radiography and CT, the sensitivity of radiography (index test) compared with CT (reference test) for the detection of talar fractures was calculated, CT was considered the gold standard. In this trauma centre, a CT examination with multiplanar reformats is recommended when a talar fracture is suspected on radiographs. 

For each patient, both radiography and CT were reviewed by at least two radiologists. Radiographs were always evaluated before reviewing the CT images to reduce reader bias.

Haapamaki (2004)-2 and Dale (2013), presented the following data on talus fractures detected by (primary) radiographs, when compared with CT, see Table 3. The data should be interpreted carefully due the retrospective nature of the studies and the lack of data on patients not undergoing CT (true negatives and false positives).

Table 3: studies reporting data on talus fractures detected by (primary) radiographs, when compared with CT

CT = Computer Tomogrpahy, MRI = magnetic resonance imaging, TP = true positives, FN = false negatives, TN = true negatives, FP = false positives, Sens = sensitivity, Spec = specificity

Calcaneus fractures

Haapamaki (2004). For description of study, see paragraph “talus fractures”.

Haapamaki (2004)-2 presented the following data on calcaneus fractures detected by (primary) radiographs, when compared with CT, see Table 4. The data should be interpreted carefully due the retrospective nature of the studies and the lack of data on patients not undergoing CT (true negatives and false positives).

Table 4: studies reporting data on calcaneus fractures detected by (primary) radiographs, when compared with CT

CT = Computer Tomography, MRI = magnetic resonance imaging, TP = true positives, FN = false negatives, TN = true negatives, FP = false positives, Sens = sensitivity, Spec = specificity

Results

Diagnostic Accuracy

No studies were found reporting the diagnostic accuracy of (primary) radiographs and CT/MRI when compared to surgical findings, in patients with acute traumatic foot injury, suspected of Chopart, Lisfranc, talus or calcaneus fractures.

Clinical management

No studies were found reporting the change in clinical management after a (primary) radiographs or CT/MRI when compared to surgical findings, in patients with acute traumatic foot injury, suspected of Chopart, Lisfranc, talus or calcaneus fractures.

Level of evidence of the literature

The level of evidence for the outcomes diagnostic accuracy and clinical management was not graded as no studies were found that matched the PICRO.

A systematic review of the literature was performed to answer the following question:

What is the diagnostic accuracy of an additional imaging with Computer Tomography (CT) or Magnetic Resonance Imaging (MRI), compared to a (non-weightbearing) foot x-ray only in patients with suspected traumatic foot injuries (talus, calcaneus, Chopart or Lisfranc)?

Relevant outcome measures

The guideline development group considered change in clinical management, sensitivity and false negatives as critical outcome measures for decision making; and specificity and false positives as important outcome measures for decision making.

A priori, the guideline development group did not define the outcome measures listed above but used the definitions used in the studies. 

For the outcome ‘change in clinical management’ the guideline development group considered a RR <0.80 and RR >1.25 (dichotomous outcomes) and a difference of 25% (continuous outcomes) as a minimal clinically (patient) important difference. For diagnostic accuracy (sensitivity, specificity, negative predictive value and positive predictive value), a difference of 10% was considered clinically relevant.

Search and select (Methods)

The databases Medline (via OVID) and Embase (via Embase.com) were searched with relevant search terms until the 11^th of January 2023. The detailed search strategy is depicted under the tab Methods. Relevant search terms were used to search for systematic reviews, RCTs, observational and other studies about diagnosing foot injuries. The search resulted in 1312 unique hits.

Studies were selected based on the following criteria:

• Trials in patients with suspected or diagnosed foot injury
• Trials comparing radiographs and CT/MRI with surgical findings
• Trials reporting diagnostic accuracy of the diagnostic modalities for detecting fractures or additional injuries

Twenty-eight studies were initially selected based on title and abstract screening. After reading the full text, twenty-eight studies were excluded (see the table with reasons for exclusion under the tab Methods), and no studies were found that matched the PICO.

Eight studies were found that compared diagnoses based on (primary) radiographs with diagnoses based on CT or MRI. As there was no comparison with surgical findings (reference), these studies did not comply with the PICRO. However, the guideline development group evaluated these studies to be relevant for answering the question: What is the diagnostic accuracy of an additional CT/MRI, compared to a (non-weightbearing) foot x-ray only in patients with suspected traumatic foot injuries (talus, calcaneus, Chopart or Lisfranc)?

Results

A description of the studies that were considered relevant for answering the research question is presented below. As these studies did not comply with the PICRO, these studies were not graded. The data of these studies is not incorporated in the Evidence tables and risk of bias tables.