Description of patient (type of occupation, indication of age, intensity of sport):
A 26 years old male with no risk factors for nonunion.
History and previous treatment:
Patient presented with a low energy external rotation injury to his ankle resulting in near dislocation of the ankle joint. The ankle was realigned under conscious sedation and immobilized in a back slab. Plain radiographs revealed a Maisonneuve fracture with diastasis of the syndesmosis.
At 8 days following injury the ankle was examined under anesthesia together with arthroscopic evaluation and debridement of the syndesmosis and medial interposed soft tissue. The syndesmosis was reduced and stabilized using two anteriorly directed Tightropes (Arthrex, Naples, FL) (Figure 1). Postoperatively the ankle was immobilized in a synthetic cast, maintained initially non weightbearing for two weeks, and followed by partial weightbearing for a further 4 weeks.
At 6 weeks postoperatively he commenced physiotherapy consisting of range of movement exercises, proprioception and peroneal strengthening progressing to functional rehabilitation.
Current complaints:
By 6 months following stabilization he still complained of some tightness at the front of the ankle with discomfort on going downstairs. He described a severe band like pain around the mid-calf, which worsened with exercise.
Physical examination:
The arthroscopy and lateral wounds had healed. There was tenderness around the fracture site and syndesmosis. The ankle had reduced a range of motion.
Radiology:
X-ray
[Picture 1]
Plain radiograph showing the unstable syndesmosis was stabilised using two anteriorly directed Tightropes.
Additional investigation (CT/MRI):
CT images confirming the fibula nonunion and sclerosis of the bone ends.
[Picture 2]
Axial MRI revealing the reduced syndesmosis and healing of the anterior inferior tibiofibular ligament (AITFL).
[Picture 3]
Intra-operative photograph after debridement of the nonunion site including drilling of the sclerotic bone ends.
[Picture 4]
Remarks:
At 9 months following injury, the fibula nonunion was explored. Fibrous tissue was removed from the fracture site with drilling of sclerotic bone. The fracture was then stabilized using a 7-hole locking compression plate (Synthes, Solothurn, Switzerland) and synthetic Stimulan bone graft (Biocomposites, Keele, UK) was applied.
By 3 months following fixation the patient reported complete alleviation of pain in the calf and improving function to the ankle (AOFAS = 91) and radiographs confirmed union.
[Picture 5]
Plain radiograph at 3 months following internal fixation of the fibula revealing healing of the fracture.
Images:
Case summary:
A 26 years old male sustained a Maisonneuve fracture with diastasis of the syndesmosis. The syndesmosis was reduced and stabilized using two anteriorly directed suture button Tightropes. At 6-month follow-up he had significant pain around the mid-calf, and also ankle pain and stiffness. Plain radiographs and CT scan revealed a fibula nonunion. At 9 months following the initial injury, the fracture was surgically debrided and stabilised using a locking compression plate, and synthetic bone graft applied. By 3 months following fixation he reported alleviation of pain and improving ankle function. Plain radiographs confirmed union. This is the first reported case of a Maisonneuve fracture treated by syndesmosis suture button stabilisation resulting in fibula nonunion. The increased stability of the syndesmosis from two anteriorly directed Tightropes may have predisposed to nonunion. We recommend that when using two suture buttons, one should be directed anteriorly and the second in a transmalleolar direction.
Question(s) to this case:
What are the experts opinion on this case?
Expert:
For maisonneuve fractures tighrope is not the ideal implant since it does not control upward movement of the fibula.
In case of a maisonneuve fracture the fibula moved into a proximal direction (by muscletraction) Before stabilizing it with a positioning screw or tightrope the fibula must be brought back to its anatomical position =distalised. A positioning screw will hold the fibula into this distalised position. However a tightrope will allow the fibula to migrate upwards again. This still does not explain the pseudarthrosis, but is ment as a general remark against tightrope for maisonneuve fractures.