[Early complications associated with total hip arthroplasty due to femoral neck fracture].

Purpose Of The Study: Fractures of the femoral neck have been serious health and social issues of the recent decades. Although up-to-date implants and perioperative care are now available, the treatment is still associated with an increased risk of postoperative complications. The aim of this study was to specify early postoperative complications and to ascertain which factors, if any, can predict them.

Material And Methods: Between October 2005 and February 2007, a total of 155 patients were treated for femoral neck fractures in our department. The group of elderly patients (n = 82) who underwent elective total hip arthroplasty for osteoarthritis served as controls. The selected pre-, peri- and post-operative characteristics were prospectively collected. Each patient was followed- up for at least one month after surgery. The data were first compared by univariate analysis and then, for statistically significant factors, their predictors were identified by the logistic regression.

Results: The average age of the patients with femoral neck fracture was 77 years and that of the control patients was 75 years. The ratio of men to women was similar in both groups; the groups differed in body height, weight, preoperative morbidity, ASA score, lymphocyte counts, severity of brain atherosclerosis, independence in walking, and self-sufficient living. The number of complications in the hip-fracture group was 87 while, in the control group, it was only 15 (p = 0.0002). The hip- fracture group showed significantly higher occurrence of postoperative delirium (34 versus 4; p = 0.001) and prosthesis dis- location (12 versus 0; p = 0.009). The subsequent multifactorial analysis showed that the risk of postoperative delirium was associated with preoperative lack of self-sufficiency (odds ratio, OR = 4.814; 95 % CI, 1.551-14.942) and the length of operative time (OR = 0.970; 95% CI, 0.951-0.989). Prosthesis dislocation was predicted by an increased height of the patient (OR = 1.087 per each cm; 95% CI 1.001-1.159). An interval between injury and surgery longer than 48 hours was not associated with higher mortality.

Discussion: Postoperative delirium is a complication found in up to 60% of the patients with surgery for femoral neck fracture. The frequency of this complication depends on the instruments used to identify cognitive dysfunction - with a more sensitive instrument cognitive dysfunction is probably detected in more patients.The higher occurrence of dislocation in the hip-fracture group is also in agreement with the literature data. On the other hand, its association with patient height should not be overestimated, because a coincidence of several other factors may have been involved in the mechanism of dislocation. Displacement can be prevented by the use of offset acetabular components and 36-mm femoral heads for primary implantation in such patients.

Conclusions: A significantly higher frequency of prosthesis dislocation and postoperative delirium was found in the patients undergoing total hip arthroplasty for traumatic indication than in the patients after elective surgery. A subsequent multifactorial analysis revealed a potential association of prosthesis dislocation with the patient's height and that of postoperative delirium with the duration of operative time and the degree of preoperative self-sufficiency.