[Clinical analysis of full-repair strategy under small incision for closed Lauge-Hansen pronation-external rotation type Ⅳ ankle fracture].

OBJECTIVE: To investigate the safety, feasibility, and efficacy of full repair strategy under small incision in the treatment of closed Lauge-Hansen pronation-external rotation type Ⅳ ankle fracture.
METHODS: The clinical data of 57 patients with closed Lauge-Hansen pronation-external rotation type Ⅳ ankle fracture treated by full repair strategy (fracture, ligament, and cartilage repair) under small incision between January 2012 and January 2017 were retrospectively analyzed. There were 31 males and 26 females, with an average age of 41.1 years (range, 21-65 years). The causes of injury included traffic accident injury in 33 cases and falling injury in 24 cases. All of them were closed fractures, including 20 cases of medial malleolus fracture, 37 cases of complete medial malleolus but deep and shallow rupture of deltoid ligament. The average time from injury to admission was 9.6 hours (range, 3-34 hours). The quality of reduction of distal tibial articular surface (based on Ketz-Sanders standard), the reduction of tibiofibular syndesmosis (the anterior and posterior distances of distal tibiofibular syndesmosis and the lateral ankle twist angle measured by CT scan at 10 mm above the ankle joint line), and the fracture healing were evaluated. The medial clear space (MCS), tibiofibular clear space (TFCS), and distal fibular tip to lateral process of talus (DFTL) were measured on the X-ray films of ankle points. Before and after operation, the pain and functional improvement of ankle joint were evaluated by visual analogue scale (VAS) score and American Orthopedic Foot and Ankle Association (AOFAS) score, and the activities of ankle dorsiflexion and plantar flexion were measured.
RESULTS: Three cases with osteochondral lesions of the talus were found during operation and all were treated with microfracture techniques. Tournament paralysis occurred in 2 cases after anesthesia. The surgical incisions healed by first intention in all patients. All the 57 patients were followed up 24-84 months, with an average of 38.6 months. All patients achieved bone healing without bone nonunion and malunion at 12 months after operation. The reduction quality of distal tibial articular surface was excellent in 56 cases and good in 1 case at 3 months after operation, the excellent and good rate was 100%. There was no significant difference in the MCS, TFCS, DFTL, anterior distance of distal tibiofibular syndesmosis, posterior distance of distal tibiofibular syndesmosis, and lateral ankle twist angle between the affected and healthy sides at 12 months after operation ( P>0.05). At last follow-up, the VAS score, AOFAS score, ankle dorsiflexion and plantar flexion activities of the affected side were significantly improved when compared with preoperative ones ( P<0.05). Compared with the healthy side, there was no significant difference in ankle dorsiflexion and plantar flexion activities ( P>0.05).
CONCLUSION: Full-repair strategy under small incisions for the treatment of Lauge-Hansen pronation-external rotation type Ⅳ ankle fracture is effective and safe. It can not only reduce wound complications, but also improve the quality of joint reduction of the ankle joint and distal tibiofibular syndesmosis. Full repair of ligaments and cartilage can improve the internal fixation strength and joint stability of the ankle joint.