The spiral blade modification of the Dynamic
Hip Screw (DHS) was designed for superior biomechanical fixation
in the osteoporotic femoral head. Our objective was to compare clinical
outcomes and in particular the incidence of loss of fixation. In a series of 197 consecutive patients over the age of 50 years
treated with DHS-blades (blades) and 242 patients treated with conventional
DHS (screw) for AO/OTA 31.A1 or A2 intertrochanteric fractures were
identified from a prospectively compiled database in a level 1 trauma
centre. Using propensity score matching, two groups comprising 177
matched patients were compiled and radiological and clinical outcomes
compared. In each group there were 66 males and 111 females. Mean
age was 83.6 (54 to 100) for the conventional DHS group and 83.8
(52 to 101) for the blade group. Loss of fixation occurred in two blades and 13 DHSs. None of
the blades had observable migration while nine DHSs had gross migration
within the femoral head before the fracture healed. There were two
versus four implant cut-outs respectively and one side plate pull-out
in the DHS group. There was no significant difference in mortality
and eventual walking ability between the groups. Multiple logistic
regression suggested that poor reduction (odds ratio (OR) 11.49,
95% confidence intervals (CI) 1.45 to 90.9, p = 0.021) and fixation
by DHS (OR 15.85, 95%CI 2.50 to 100.3, p = 0.003) were independent
predictors of loss of fixation. The spiral blade design may decrease the risk of implant migration
in the femoral head but does not reduce the incidence of cut-out
and reoperation. Reduction of the fracture is of paramount importance
since poor reduction was an independent predictor for loss of fixation
regardless of the implant being used. Cite this article:
A review of the literature showed a discrepancy between biomechanical and clinical studies on fracture fixation failure in patients with poor bone quality. The objective of the present study is to assess the influence of local bone status on complications after surgical treatment of proximal humerus fractures. A prospective cohort study was initiated in 2007. The inclusion criteria were closed displaced fractures of the proximal humerus, primary fracture treatment with a Philos plate, patients aged 50 to 90, normal pre-trauma function of both shoulders in accordance to age, and monotrauma. There was active follow-up for one year with radiological assessment at clinical centers from four countries. Bone quality at the proximal humerus was determined preoperatively for the contralateral side of the fracture by CT scan, and at the contralateral radius within six weeks post-surgery by DXA. The occurrence of complications was monitored up to one year post-surgery. Independent x-ray evaluation and final classification of all complications will be performed at the end by a study review board using anonymous data and x-rays.Introduction
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