Introduction

Studies have compared outcomes of first metatarsophalangeal joint (MTPJ1) implant hemiarthroplasty and arthrodesis, but there is a paucity of data on the influence of patient factors on outcomes. We evaluated data from a prospective, RCT of MTPJ1 implant hemiarthroplasty (Cartiva) and arthrodesis to determine the association between patient factors and clinical outcomes.

Introduction: We state that preserving the hip might be optimum in treatment of patients with dislocated femoral fractures presuming that the fractures unite. In order to be able to choose the right treatment for the patient with a dislocated femoral neck fracture, we have hypothesized that lack of blood flow and development of ischemia might have influence on outcome of the osteosynthesis. In this study we have established microdialysis and laser Doppler measurements in patients with a dislocated femoral neck fractures.

Methods and materials: 14 patients with dislocated fractures of the femoral neck were osteosynthezised by using 2 cannulated screws. During the operation blood flow was measured with laser Doppler in order to detect pulsatile flow, and microdialysis was performed to detect ischemia. Both measurements were made in the femoral head and with the greater trochanter as control. The parameters measured were lactate, pyruvate, glycerol and glucose concentrations. Lactate/pyruvate ratio was calculated in order to estimate ischemia defined as a value over 25. Measurements were done after the fracture was reduced, and during osteosynthesis. Data are presented as mean with standard deviation (SD) in brackets.

Results: In all but one patient laser Doppler showed pulsatile flow in the greater trochanter, whereas 8 patients had flow in the femoral head. In the greater trochanter the mean lactate/pyruvate ratio was 11 (7.55), in the femoral heads the mean ratio was 27.99 (21.24) although 4 heads did not show ischemia (p=0.0004). The values for glucose in the trochanter and the femoral head are 2.47 mM(1.92) and 1.53 mM(1.37) respectively, and for glycerol 0.16 mM(0.09) and 0.25 mM(0.22). During the observation period two patients were reoperated, one with hemiarthroplasty 3 months after the osteosynthesis due to failure of the osteosynthesis; the patient had flow measured by laser Doppler and ischemia with microdialysis. One had a resection arthroplasty due to infection.

Conclusion: To our knowledge it is the first time that laser Doppler and microdialysis has been established in patients with dislocated femoral neck fractures. Further studies will have to evaluate whether laser Doppler and microdialysis in combination with fracture related parameters can predict failure of the osteosynthesis. This might enable us to establish a treatment algorithm to be used in the daily clinic.