Deltoid ligament reconstruction in ankle fractures – does it prevent pes planus?

J. Aamir, T. Huxley, M. Clarke, N. Dalal, A. Johnston, D. Rigkos, J. Kutty, C. Gunn, C. Condurache, D. McKeever, A. Gomaa, L. Mason

Introduction: Deltoid ligament reconstruction (DLR) is an important factor in the consideration of pes planus deformity. There is little evidence in the literature determining whether DLR could mitigate the risk of patients acquiring flat foot postoperatively following deltoid ligament injury

Aim: Our objective was to establish if there was a difference in pes planus deformity in patients who underwent DLR during their ankle fracture fixation compared to those who did not.

Methods:  A retrospective analysis of post-operative weight bearing radiographs was performed of patients who underwent ankle fracture fixation. Inclusion criteria were confirmed deltoid instability presurgery without medial malleolar fracture and post operative weightbearing radiographs at least 6 weeks post-fixation. Patients were categorised into no deltoid ligament reconstruction (nDLR) and having DLR. Radiographic pes planus parameters involved Meary’s Angle assessment. Other fracture morphology was classified.

Results: A total 723 ankle fractures were screened. 122 patients were included for further analysis. There were 94 patients in the nDLR group and 28 patients in DLR group. The mean Meary’s Angle was 15.81 (95% CI 14.06, 17.56) degrees in the nDLR group and -.2 (95% CI -3.86, 3.82) in the DLR group. This was statistically significant (p<.001). There was no significant difference in medial clear space measurements (2.90mm v 3.19mm, p = 0.145). There were significantly more pes planus patients in the nDLR than the DLR group (p<.001, 90.5% vs 25%).

Conclusion: In this study there was significantly greater pes planus parameters in patients not undergoing DLR. Patients undergoing DLR had on average normal parameters, whilst those not undergoing DLR had on average severe pes planus. The benefits of DLR are not only maintaining ankle stability but maintaining medial arch integrity, and this should be taken into account in a future study on DLR.