Etiopathology and treatment-related aspects of hip fracture

Hip fracture is a trauma with serious consequences, especially in the elderly. Etiological factors should be known better than nowadays to recognize the individuals at high risk. Also, the treatment of displaced femoral neck fractures has been controversial, and the factors leading to a functional outcome are not known well. The true impact of deep infection on the outcome after hip fracture surgery has also been insufficiently examined. The thesis is based on two etiological studies. In the first study, the geometrical parameters of the upper femur and pelvis in postmenopausal women with hip fracture were (n = 70) compared to ageadjusted controls (n = 40). Measurements were made from position-standardized and calibrated pelvic plain x-rays. The differences between the two different types of hip fracture, femoral neck fractures (n = 46) and trochanteric fractures (n = 24) were also defined. High femoral neck/shaft angle (NSA), thin femoral cortices, low femoral shaft diameter (FSD) and trochanter width and the pelvic dimensions associate strongly with the hip fracture risk in postmenopausal women. Greater NSA, smallest outer pelvic diameter and acetabular width, narrower FSD and smaller femoral neck/ shaft cortex ratio were associated with femoral neck fracture rather than trochanteric fracture in postmenopausal women. In the second study, lifetime factors, some bone metabolism markers and bone mineral density were analyzed from postmenopausal women (n = 74; 49 with femoral neck fracture, 25 with trochanteric fracture) and age-adjusted controls (n = 40). Impaired functional ability, use of loop diuretics, antidiabetic, antidepressant and neuroleptic drugs, some concurrent diseases, such as stroke, diabetes, malignancy, cardiovascular diseases, low bone mineral density of the upper femur, low serum calcium, low serum 25-hydroxyvitamin D and high serum calcitonin, seem to be related to the risk of hip fracture, while low bone mineral density and low serum calcitonin are related to the trochanteric type of fracture in postmenopausal women. The treatment of displaced femoral fractures included two prospective case-control studies, and the first of these involved a comparison (357 matched pairs) of patients with osteosynthesis (OS) with two pins in Lund and patients with uncemented hemiarthroplasty (HA) in Oulu. The patients treated with OS had 4 months after fracture better ambulatory capacity, used walking aids less often and had less pain than the patients treated with HA. The other comparison (84 matched pairs) was made between OS with three screws and uncemented HA, and it revealed no significant differences between HA and OS in the short-term functional outcome. Both studies revealed a higher re-operation rate in OS patients than uncemented HA patients. The case-control study with 29 matched pairs showed that deep infection after a hip fracture operation impairs the short-term functional outcome and slightly increases mortality, with an attributable mortality rate of 10 %. In conclusion, this thesis suggests that the geometry of the upper femur and pelvis, the aforesaid lifetime factors, the aforesaid metabolism markers and bone mineral density are associated with the etiopathology and type of hip fracture in postmenopausal women. The short-term functional outcome was better in OS patients treated with two pins compared to uncemented HA, but the higher re-operation rate should be considered among the OS patients. Deep infection is a serious complication of hip fracture surgery, which impairs function and increases mortality.