Joint-preserving osteotomy of malunited ankle and pilon fractures

Abstract

Malunion and nonunion after ankle and pilon fractures regularly lead to the development of painful functional impairment even in cases of only mild axial deviation or residual joint incongruity. Involvement of the tibial pilon results in rapid progression of posttraumatic ankle arthritis. Corrective osteotomy with joint preservation aims at secondary anatomical reconstruction with functional rehabilitation. This requires a careful preoperative analysis and will be possible in carefully selected cases only. Prerequisites for successful reconstruction are intact cartilage, sufficient bone quality, residual joint function and good patient compliance. Since the works of B. G. Weber, joint-sparing osteotomy is an established treatment option for malunited malleolar fractures with reliable long-term results and low rates of complications and secondary fusions. Key to success is the re-establishment of the length of the distal fibula and repositioning into the tibial incisura in cases of syndesmotic instability. Corrections of the medial malleolus and posterior tibial fragment are less frequent. Corrective intra-articular osteotomies for malunited pilon fractures are rarely feasible because of manifest arthritis at the time of patient presentation in most cases. Besides case reports there is only one series of 14 patients available in the literature. At 5-year follow-up, a good to excellent result was seen in 10 cases and secondary ankle fusion was done in 2 patients with a poor result. Anatomical reconstruction of malunited tibial pilon fractures appears to be a viable treatment option besides arthroplasty and fusion in carefully selected patients.

Early Corrections after Failed Ankle Fracture Fixation

“…The medial malleolus is initially fixed with K wires to act as a medial restraint and finally secured with a wire cerclage, which is anchored in the tibia through a metaphyseal screw. If the cartilage-bone junction of the distal fibula cannot be distinguished radiologically as a spike in the lateral contour because of the fracture anatomy, correction of the lateral joint space must be performed under direct vision [22], though the correct length of the fibula cannot be finally assessed in all cases.…”

“…If the exact extent of the deformity (shortening, rotation, translation) is analysed in the CT scan, correction can be achieved accurately to 1.3 mm and 1.5°even with two-dimensional fluoroscopic control [44]. Kirschner wires, which are inserted exactly in the angle or gap of the diagnosed deformity, facilitate anatomical correction [22]. The anterior tubercle of the distal tibia and that of the distal fibula must be clinically in alignment.…”

“…7). Exact reduction of the fragment is impeded by the pull of the syndesmosis and the ability to check it in situ and under fluoroscopic control is limited especially if internal fixation of the medial and lateral malleolus has already been performed, as the fixation material is then projected over the posterior malleolar fracture [22]. In addition, impacted, intercalary fragments, which are often only identifiable on CT scan, are obstacles to reduction [49].…”

“…Standard fixation meth-ods often lead to failure in these cases. Shortening, malrotation and malpositioning of the distal fibula in the tibial incisura are the most frequent postoperative deformities [18,21,22]. Bony injuries of the anterior and posterior tibial rim play an important part in the latter, which interfere with the integrity of the tibial incisura and are associated with instability of the syndesmosis [23].…”

“…Internal fixation of the medial malleolus, like that of the lateral malleolus, can likewise result in rotational and axial malpositioning [20,22]. Relevant deformities of the medial malleolus (≥ 2 mm step-off or medial translation) should be corrected according to the principles presented above in order to restore congruence of the ankle mortise and the medial joint surface.…”