Predictors of metalwork failure and non-union after hindfoot Charcot reconstruction

A.A. Najefi, O. Chan, R. Zaidi, T. Hester, V. Kavarthapu

Introduction: Surgical reconstruction of deformed Charcot feet carries high risk of non-union, metalwork failure and deformity recurrence. The primary aim of this study was to identify the factors contributing to these complications following hindfoot Charcot reconstructions.  

Methods: We retrospectively analysed patients who underwent hindfoot Charcot reconstruction with an intramedullary nail between 2007 and 2019 in our unit. Patient demographics, co-morbidities, weightbearing status and post-operative complications were noted. Metalwork breakage, non-union, deformity recurrence, concurrent midfoot reconstruction and the measurements related to intramedullary nail were also recorded.  

Results: There were 70 patients with mean follow up of 50±26 months. Seventy-two percent were fully weightbearing at 1 year post-operatively. The overall union rate was 83%. Age, BMI, HbA1c and peripheral vascular disease did not affect union. The ratio of nail diameter and isthmus was greater in the united compared to the non-united group (0.90±0.06 and 0.86±0.09, respectively;p=0.03). Supplemental compression devices were used for 33% of those in the united compared to 8% in the non-united group (p=0.04). All patients in the non-union group did not have a miss-a-nail screw. Metalwork failure was seen in 13 patients(19%).There was a significantly greater distal screw metalwork failure in those with supplementary bridging of tibia to midfoot (23% vs. 3%;p=0.001). An intact medial malleolus was found more frequently in those with intact metalwork (77% vs. 54%, respectively;p=0.02) and those with union (76% vs. 50%;p=0.02). Broken metalwork occurred more frequently in patients with non-unions (69% vs. 8%;p<0.001) and deformity recurrence (69% vs. 9%;p<0.001).  

Conclusion: Satisfactory clinical and radiographic outcomes occur in over 80% of patients. Union after hindfoot reconstruction occurs more frequently with an isthmic fit of the intramedullary nail, supplementary compression and miss-a-nail screws. An intact medial malleolus is protective against non-union and metalwork failure. Broken metalwork is linked to deformity recurrence and non-union.