SLR - May 2022 - Elie Touma, DPM
Reference: Rikken QGH, Hagemeijer NC, De Bruijn J, Kaiser P, Kerkhoffs GMMJ, DiGiovanni CW, Guss D. Novel Values in The Radiographic Diagnosis of Ligamentous Lisfranc Injuries. 2022 Feb 22:S0020-1383(22)00150-4. doi: 10.1016/j.injury.2022.02.044. Epub ahead of print. PMID: 35279293.Level of Evidence: Level 3
Scientific Literature Review
Reviewed By: Elie Touma, DPM
Residency Program: HCA Florida Northwest Hospital – Margate, FL
Podiatric Relevance: Patients who present to the emergency room with midfoot pain are often screened for possible Lisfranc injury. The gold standard to determine Lisfranc instability are bilateral weight bearing radiographs to evaluate the joint space widening between the medial cuneiform and the second metatarsal base. A diastasis of >2 millimeters (mm) relative to the contralateral foot is indicative of an instability. Subtle Lisfranc instabilities can be challenging and have the potential for misdiagnosis. A missed diagnosis can have dire consequences such as midfoot instability, chronic pain, and degenerative joint diseases. The authors wanted to evaluate the ideal cut off radiographic values for diagnosis of Lisfranc instability among patient who had a confirmed ligamentous injury. Furthermore, the study aimed to see if the same measurement for detecting instability can also be used with patients with Hallux Valgus (HV) and if this would affect the result.
Methods: The study is a retrospective cohort study of patients surgically confirmed and treated for ligamentous Lisfranc instability with a separate cohort of patients with preexisting hallux valgus from 1991 to 2018. Patients were excluded if they were younger than 16, did not have preoperative bilateral weightbearing radiographs, chronic injuries associated with midfoot fractures or history of midfoot injury of fracture dislocations. Similar exclusion criteria were given to the patients with HV. The parameters to diagnose instability were the diastasis (mm) between medial cuneiform and the second metatarsal, diastasis(mm) first intermetatarsal, alignment(mm) of second metatarsal cuneiform joint and surface area(mm^2) of medial cuneiform /2nd metatarsal radiographically. A Receiver Operator Correlation (ROC) was used to determine the cut off values. Interclass Correlation (ICC) was utilized to also determine the reliability of the surface area measurements.
Results: A total of 47 patients met the inclusion criteria and 25 patients met in the HV group. The Lisfranc group showed an increased diastasis between the second and first metatarsal and intermetatarsal. The surface area was also larger on the injured side. At the second metatarsal cuneiform malignment, second metatarsal step off and arch height showed significant differences between the injured and uninjured side. In the HV group there was no statistical significance in all criteria that were evaluated between both injured and uninjured feet. It was found that sensitivity and specificity were low between the first and second metatarsal.
Conclusions: Authors determined that clinician should focus on the alignment between the second metatarsal cuneiform joint and that a threshold 0.3 mm had a high sensitivity. A diastasis of 2.1 mm between the medial aspect of the second metatarsal base relative to the medial cuneiform provided a high level of specificity. Limitations were that the reviewers of the images were not blinded and no standardized weightbearing or foot pressure protocol were utilized. The study provides a model for radiographic measurements that clinicians can use to help to determine if an instability is present. The consequences of Lisfranc injuries can be life changing. As foot and ankle surgeons, we should be able to have radiographic protocols to ensure no misdiagnosis occurs.