The aim of this study is to analyse the radiological outcomes and predictors of avascular necrosis following 2-hole DHS in Garden I and II neck of femur fractures in patients more than 60 years with a minimum follow up of one year.

We retrospectively reviewed 51 consecutive patients aged more than 60 years who underwent DHS fixation for Garden I and II fractures. Demographics, fracture classification, time to surgery, pre-operative AMTS, preoperative posterior tilt angle, quality of reduction, pre and post-operative haemoglobin(hb), creatinine and comorbidities were analysed for correlation with AVN using Chi-Square test, Independent Sample and paired t test.

There were 40 (78.4%) females and the mean age of the cohort was 77 years. 28 and 23 were Garden I and II NOF fractures respectively. Union was observed in all our patients except one(kappa =1). 12/51(23.5%) developed AVN of the femoral head. Statistically significant higher incidence of AVN was noted in patients with a pre-op tilt angle > 200 (p = 0.006). The mean drop in Hb was higher in patients who developed AVN (21.5 g/L) versus the non-AVN group (15.9 g/L) (p = 0.001). There was no difference in AVN rates with respect to laterality, mean time to surgery, pre-op AMTS and Charlson comorbidity index. 4/52 (7.6%) had re-operations (one hardware prominence, two conversions to arthroplasty, one fixation failure during the immediate post-op period). The 30-day and one year mortality rates were 1.9 % and 11.7 % respectively.

2-hole DHS fixation in undisplaced NOF fractures has excellent union rates. A pre-operative posterior tilt angle of >200 and a greater difference in pre and post operative haemoglobin were found to correlate positively with the progression to AVN . No correlation was observed between AVN and time to surgery, laterality, quality of reduction and comorbidities.

Abstract