Is Repair of the Superficial Deltoid Ligament Alone Enough to Restore Medial Ankle Stability in Deltoid Ligament Injuries? A Cadaveric Study

CATEGORY: Trauma INTRODUCTION/PURPOSE: Deltoid ligament injuries are controversial in many aspects: the best method to assess the stability of a Weber B fibular fracture, the indications of deltoid repair after lateral side surgical fixation, the best technique of deltoid repair and the efficacy of superficial deltoid repair alone, compared to repair of both deep and superficial deltoid ligaments, to restore medial ankle stability. The last point is specifically important because of the technical difficulty of repairing the deep deltoid ligament, specially if performed after fixation of the fibular fracture and the syndesmosis, which is the common scenario. The aim of the study was to evaluate the ability of superficial deltoid repair without deep deltoid repair to restore medial ankle stability in cases of deltoid ligament injuries. METHODS: Ten fresh frozen ankle cadaveric specimens were used. Anteromedial dissection was performed to expose the ankle joint and to visualize the deltoid ligament. After good exposure, stress valgus and stress external rotation tests were performed with observation of the medial gutter and the medial part of the ankle joint for any widening. In all specimens, the ankle was stable at this point. Then, the superficial deltoid ligament was detached by sharp dissection from the medial malleolus followed by transection of the deep deltoid ligament completely at its midportion. Stress valgus and stress external rotation tests were repeated to demonstrate the gross instability of the ankle joint. Then, the superficial deltoid ligament was repaired using a suture anchor to the medial malleolus without any repair of the deep deltoid ligament. Then, stress valgus and stress external rotation tests were performed again to assess the medial ankle stability. RESULTS: All ankles were stable initially as confirmed by stress valgus and stress external rotation tests. After cutting both components of the deltoid ligament, the ankles were found to be grossly unstable using the same tests. After repair of the superficial deltoid, all ankles were stable again with a medial space equal to the initial status and with negative stress valgus and stress external rotation tests. CONCLUSION: Surgical repair of the superficial deltoid ligament without repair of the deep deltoid ligament in cases of deltoid ligament injury may be sufficient to restore medial ankle stability. Limitations of the study include that all potential secondary restraints are intact in the cadaveric study compared to the actual situation where other structures like the capsular attachments may be injured especially if a fracture dislocation is encountered. Clinical trials are needed to confirm this finding.