Renal function after elective total hip replacement: Incidence of acute kidney injury and prevalence of chronic kidney disease

Background and purpose — Acute kidney injury (AKI) is associated with increased short-term and long-term mortality in intensive care populations and in several surgical specialties, but there are very few data concerning orthopedic populations. We have studied the incidence of AKI and the prevalence of chronic kidney disease (CKD) in an elective population of orthopedic patients undergoing primary total hip replacement, hypothesizing that chronic kidney disease predisposes to AKI. Patients and methods — This was a single-center, population-based, retrospective, registry-based cohort study involving all primary elective total hip replacements performed from January 2003 through December 2012. Patient demographics and creatinine values were registered. We evaluated the presence of CKD and AKI according to the international guidelines for kidney disease (KDIGO Acute Kidney Injury Workgroup ). Results — 3,416 patients were included (2,064 females (60%)). AKI (according to KDIGO criteria) was seen in 75 patients (2.2%, 95% CI: 1.7–2.7) in the course of primary total hip replacement. Of these, 26 had pre-existing CKD of class 3–5. Pre-existing CKD of class 3–5, indicating moderately to severely reduced kidney function, was seen in 374 individuals (11%). Interpretation — Development of acute kidney injury appears to be a substantial problem compared to other complications related to elective total hip arthroplasty, i.e. luxation and infection. Patients with pre-existing chronic kidney disease may be especially vulnerable. The clinical impact of acute kidney injury in an elective orthopedic population remains to be elucidated

Preoperative BMD does not influence femoral stem subsidence of uncemented THA when the femoral T-score is > –2.5

Background and purpose — It is believed that in uncemented primary total hip arthroplasty (THA) the anchorage of the stem is dependent on the level of bone mineral density (BMD) of the femoral bone. This is one of the reasons for the widely accepted agreement that a cemented solution should be selected for people with osteoporosis or age > 75 years. We evaluated whether preoperative BMD of the femur bone is related to femoral stem migration in uncemented THA. Patients and methods — We enrolled 62 patients (mean age 64 years (range 49–74), 34 males) scheduled for an uncemented THA. Before surgery we undertook DEXA scans of the proximal femur including calculation of the T- and Z-scores for the femoral neck. Evaluation of stem migration by radiostereometric analysis (RSA) was performed with 24 months of follow-up. In 56 patients both preoperative DEXA data and RSA data were available with 24 months of follow-up. Results — None of the patients had a T-score below –2.5. We found no statistically significant relationship between preoperative BMD and femoral stem subsidence after 3 or 24 months. When comparing the average femoral stem subsidence between 2 groups with T-score > –1 and T-score ≤ –1, respectively, we found no statistically significant difference after either 3 or 24 months when measured with RSA. Interpretation — In a cohort of people ≤ 75 years of age and with local femur T-score > –2.5 we found no relationship between preoperative BMD and postoperative femoral stem subsidence of a cementless THA