Ankle arthroscopy for diagnosis and treatment of Danis-Weber type B ankle fracture associated with injury to the distal tibiofibular syndesmosis

Abstract

Objective To evaluate the clinical value of ankle arthroscopy in diagnosis and treatment of Danis-Weber type B ankle fracture associated with injury to the distal tibiofibular syndesmosis. Methods A retrospective study was conducted of the 35 patients who had been treated at Department of Orthopaedics, Ruijin Hospital North for Danis-Weber type B ankle fracture from February 2014 to December 2016. They were 23 males and 12 females, with an average age of 43.1 years (from 18 to 65 years). Each of them underwent 4 examinations to detect whether injury to the distal tibiofibular syndesmosis was complicated or not: preoperative CT and MRI, C-arm roentgenography and ankle arthroscopy before and after internal fixation of the ankle. The diagnostic rates of the complicated injury by the 4 examinations were compared. The patients complicated with injury to the distal tibiofibular syndesmosis received surgical repair of the injury using TightRope in addition to internal fixation of the ankle, and injury to the deltoid ligament was repaired simultaneously using 3.5 mm anchor nails in case the injury was concomitant. The repair and stability of the distal tibiofibular syndesmosis were observed using ankle arthroscopy again. Results The Cotton and external rotation tests under C-arm roentgenography before surgery and after internal fixation of the ankle demonstrated that 13 cases were complicated with injury to the distal tibiofibular syndesmosis. Of the other 22 patients who had not been diagnosed with the injury by C-arm roentgenography, 6, 13 and 11 were diagnosed with the injury respectively by CT, MRI and ankle arthroscopy. The diagnostic rates of Danis-Weber type B ankle fracture associated with injury to the distal tibiofibular syndesmosis were 37.1% (13/35), 54.3% (19/35), 74.3% (26/35) and 68.6% (24/35) respectively by C-arm roentgenography, CT, MRI and ankle arthroscopy. In the sensitivity to the injury, MRI > ankle arthroscopy > CT > C-arm roentgenography, with significant differences between them (P<0.05). The ankle arthroscopy confirmed the repair efficacy in the 24 patients complicated with injury to the distal tibiofibular syndesmosis and negative results of Cotton and external rotation tests in them. Additionally, ankle arthroscopy revealed 16 cases of injury to the deltoid ligament at the medial ankle. Conclusions Ankle arthroscopy can provide evidence for correct diagnosis and treatment of Type B ankle fracture complicated with injury to the distal tibiofibular syndesmosis, because it allows direct observation of the medial deltoid ligament of the ankle and the distal tibiofibular syndesmosis. It can be also used to assess the stability of the tibiofibular syndesmosis after repair of the injury. Key words: Ankle joint; Fractures, bone; Diagnosis; Ankle arthroscopy; Distal tibiofibular syndesmosis injury