Accuracy and Measurement Error of the Medial Clear Space of the Ankle

Metitiri, Ogheneochuko; Ghorbanhoseini, Mohammad; Zurakowski, David; Hochman, Mary G.; Nazarian, Ara; Kwon, John Y.

doi:10.1177/1071100716681140

Cited by 25 publications

(23 citation statements)

References 29 publications

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“…Gougoulias and Sakellariou 8 proposed a theory, based on the anatomy and biomechanical properties of the deltoid ligament, that the deep layer plays a crucial role in fracture stability. Nonetheless, treatment decisions are determined by differences of as little as 1 to 2 mm, and Metitiri et al 17 highlighted the high degree of error and poor accuracy of MCS measurements and suggested that measuring the MCS can be difficult because it relies on the quality of the radiograph and ankle position.…”

Section: Discussionmentioning

confidence: 99%

Ultrasonographic Assessment of Deltoid Ligament Integrity in Ankle Fractures

et al. 2019

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Background: Regardless of fibular status, the presence of a superficial deltoid ligament disruption or a combination of deep and superficial deltoid ligament disruption is central to the decision-making process in treating ankle fractures. The aims of the present study were to test whether ultrasonography can assess deltoid ligament integrity and to determine its validity and reliability by comparing it with gravity stress radiography. Methods: A consecutive series of 81 eligible patients with a nondisplaced or minimally displaced fibula fracture identified on a standard radiograph were prospectively enrolled. All patients underwent gravity stress radiography and ultrasonography. Image analysis included the layer type, integrity, and tear site of the deltoid ligament. Ultrasound validity and intra- and interobserver reliability were assessed by the interpretations of the first author and an independent observer who were blinded to the results. Results: Of all patients, 64 (79.0%) had a deltoid ligament disruption; most of the tears were of both the superficial and deep layers, partial and proximal attachment tears, and only 8 (12.5%) were complete tears. Patients with an intact deltoid ligament had a mean medial clear space (MCS) value of 2.7 ± 0.5 mm, and those with deltoid ligament tears had a mean MCS value of 5.9 ± 3.4 mm ( P < .001). In a comparison between ultrasonography and gravity radiography, we found a sensitivity of 100% versus 97%, a specificity of 90% versus 100%, a positive predictive value of 97% versus 100%, and a negative predictive value of 100% versus 90%, respectively. The intra- and interobserver reliability was evaluated as almost perfect in all conditions. In a comparison between ultrasonography and gravity radiography, we found a sensitivity of 100% versus 97%, a specificity of 90% versus 100%, a positive predictive value of 97% versus 100%, and a negative predictive value of 100% versus 90%, respectively. Conclusion: Ultrasonography proved to be an accurate tool, allowing the identification of deltoid ligament disruption and the involved components in a more dynamic fashion. Its relative ease of use and lack of ionizing radiation make it a useful and confident technique that can be performed by an orthopedist. Level of Evidence: Level II, prospective comparative study.

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Section: Discussionmentioning

confidence: 99%

Ultrasonographic Assessment of Deltoid Ligament Integrity in Ankle Fractures

et al. 2019

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“…They also showed a mean difference in MCS between paired ankles of 0.6 ± 0.6 mm and thereby recommended routine contralateral radiographic comparison of MCS to assess for pathologic widening in the setting of known anatomic variation and to avoid the potential for false-positives. 45 Further support for the cautious use of an absolute measurement was provided by Metitiri et al 38 Using 3 normal ankle cadaver specimens, the authors transected the deltoid/syndesmotic ligaments and artificially widened the mortise using resin blocks to a defined distance of 4 and 6 mm (the third specimen was left intact). Radiographs were obtained of each cadaver at varying degrees of rotation, and orthopedic providers were asked to measure the MCS using a standardized technique.…”

Section: What Defines An Anatomic Mortise?mentioning

confidence: 99%

Evaluation and Significance of Mortise Instability in Supination External Rotation Fibula Fractures: A Review Article

et al. 2018

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“…While previous works have demonstrated near perfect intra-/interobserver agreement when measuring MCS, others have demonstrated poor interobserver agreement. 7,15,17 Furthermore, many previously published studies did not analyze the reliability of measurement or perform any blinding, with the resultant conclusions deemed valid and appropriately clinically relevant. Taking this into consideration, using a single experienced reviewer eliminated potential interobserver discrepancies while relying on previous investigations that appear to obviate the need for intraobserver analysis.…”

Section: Discussionmentioning

confidence: 99%

Effect of Muscle Activation on the Gravity Stress View in Unstable Weber B Ankle Fractures

et al. 2020

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Background: In the setting of apparently isolated distal fibula fractures, the gravity stress view (GSV) is a validated method to determine mortise stability. There is currently no published data evaluating whether dynamic muscle activation can reduce an unstable mortise. If patients with instability can overcome gravity, resultant images could yield false-negative results. The goal of this investigation was to determine if patient effort can influence medial clear space (MCS) measurements in proven unstable bimalleolar-equivalent ankle fractures. Methods: Patients presenting with Weber B fibula fractures were assessed for mortise stability using the GSV. If the GSV demonstrated instability based on MCS widening >4 mm, 3 additional views were performed: GSV with an assistant maintaining the ankle in a neutral position; GSV with the patient actively dorsiflexing to neutral; and GSV with the patient actively dorsiflexing and supinating the foot. Twenty-four consecutive patients met inclusion criteria, with a mean age of 48.7 (range, 22-85) years. Fifteen patients (62.5%) were female and 9 (37.5%) were male. The laterality was evenly divided. Results: The mean MCS was 5.8 ± 2.0 6.0 ± 2.6, and 6.2 ± 2.7 mm for the manual assist, active dorsiflexion, and active supination radiograph measurement groups, respectively ( P = .434). Only 5 of 24 subjects had any measurable decrease in their MCS with active supination, with a maximum change of 1.2 mm. The remainder of the patients had an increase in MCS ranging from 0.1 to 4.0 mm. Conclusion: There was no significant difference between measurement states indicating that muscle activation is unlikely to yield a false-negative result on GSV. Mortise instability, secondary to deep deltoid injury in the presence of gravity stress, is unlikely to be actively overcome by dynamic stabilizers, supporting the validity and specificity of the GSV. Level of Evidence: Level III, prospective study.

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Accuracy and Measurement Error of the Medial Clear Space of the Ankle

Abstract: This high degree of measurement error and lack of precision should be considered when deciding treatment options based on MCS measurements.

Cited by 25 publications

References 29 publications

Ultrasonographic Assessment of Deltoid Ligament Integrity in Ankle Fractures

Ultrasonographic Assessment of Deltoid Ligament Integrity in Ankle Fractures

Evaluation and Significance of Mortise Instability in Supination External Rotation Fibula Fractures: A Review Article

Effect of Muscle Activation on the Gravity Stress View in Unstable Weber B Ankle Fractures

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