We studied 217 patients with an unstable trochanteric or subtrochanteric fracture who had been randomly allocated to treatment by either internal fixation with a standard Gamma nail (SGN) or a Medoff sliding plate (MSP, biaxial dynamisation mode). Their mean age was 84 years (65 to 99) and they were reviewed at four and 12 months after surgery. Assessments of outcome included general complications, technical failures, revision surgery, activities of daily living (ADL), hip function (Charnley score) and the health-related quality of life (HRQOL, EQ-5D).The rate of technical failure in patients with unstable trochanteric fractures was 6.5% (6/ 93) (including intra-operative femoral fractures) in the SGN group and 5.2% (5/96) in the MSP group. In patients with subtrochanteric fractures, there were no failures in the SGN group (n = 16) and two in the MSP group (n = 12). In the SGN group, there were intraoperative femoral fractures in 2.8% (3/109) and no post-operative fractures. There was a reduced need for revision surgery in the SGN group compared with the MSP group (8.3%; 9/108; p = 0.072). The SGN group also showed a lower incidence of severe general complications (p < 0.05) and a trend towards a lower incidence of wound infections (p = 0.05). There were no differences between the groups regarding the outcome of ADL, hip function or the HRQOL. The reduction in the HRQOL (EQ-5D index score) was significant in both groups compared with that before the fracture (p < 0.005).Our findings indicate that the SGN showed good results in both trochanteric and subtrochanteric fractures. The limited number of intra-operative femoral fractures did not influence the outcome or the need for revision surgery. Moreover, the SGN group had a reduced number of serious general complications and wound infections compared with the MSP group. The MSP in the biaxial dynamisation mode had a low rate of failure in trochanteric fractures but an unacceptably high rate when used in the biaxial dynamisation mode in subtrochanteric fractures.The negative influence of an unstable trochanteric or subtrochanteric fracture on the quality of life was significant regardless of the surgical method.The treatment of stable trochanteric fractures of type 1 or type 2 according to the classification of Jensen and Michaelsen (J-M) 1 is uncontroversial and good results can be expected with various implants. 2 Most authors favour the sliding hip screw (SHS) and recent studies on this method have shown rates of failure below 2%. 3,4 In the case of unstable trochanteric fractures (J-M type 3 to 5) 1 and subtrochanteric fractures, 5 the treatment is more controversial and the rate of failure for the SHS in these fractures is considerably higher, ranging from 4% to 15%. 3,4,[6][7][8][9] The Medoff sliding plate (MSP) evolved from the SHS and gives axial compression along both the femoral neck (optional) and the femoral shaft. It has produced remarkably good results in prospective trials in both unstable trochanteric and subtrochanteric fractures with a rate of fa...