Assessing the risk factors in the management of diabetic ankle fractures: can rigid-long segment fixation (RISF) improve outcomes

R. Ahluwalia, F. Rhamen, V. Kavarthapu

Introduction: Diabetes is a poor prognostic indicator after an ankle fracture. Many surgeons avoid operating due to concerns regarding complications.

Method: We performed a retrospective analysis of complication rates for acute ankle fractures in diabetics with a control non-diabetic patient treated by all surgeons in our unit and assessed factors for success including long-segment fixation. Patient records were cross-referenced with departmental databases and a review of all ankle fractures managed in our department was conducted from 2012. All patients subjected to a retrospective-review of their follow-up for at least 6-months. Radiographs were assessed of the ankle before and at completion of treatment being reviewed independently (RA & FR). We identified the HB1Ac (diabetic-control) and systematic co-morbidities. Fractures were classified into unimalleolar, bi malleolar and trimalleolar and surgery grouped into standard or long-segment-rigid fixation. Statistical analysis was conducted using absolute/relative risk (RR); numbers needed to treat (NNT) were calculated. We compared a control-group, a diabetic group managed conservatively, and undergoing surgery; comparing the concept of rigid fixation and prolonged imobilisation in isolation or combined. Further sub-analysis conducted assessing diabetic neuropathy, retinopathy and nephropathy. Ethics approval was granted as per our institutional policy by our governance lead.

Results: We identified 154 diabetic ankle fractures, seventy-six had conservative-treatment; 78 had operative fixation of which 23 had rigid-long-segment-fixation. The diabetic-groups had a higher risk-relative-risk of complication - 3.2 (P< 0.03) being linked to systematic complications of diabetes e.g. neuropathy 5.8 (P< 0.003); HBA1c 4.6 P< 0.004); and neuropathy or retinopathy 6.2 (P< 0.0003). Relative-risk reduction of complications occurred following surgery with prolonged immobilization (0.86) and rigid-fixation (0.65). The Number-Needed-to-Treat required to see a benefit from rigid fixation was 7.

Conclusions: Diabetics have a higher risk for complications, however the risk is not as great as previously reported. We provide evidence of rigid-long-segment-fixation with prolonged-immobilization improving outcomes.