Revision Risk After Primary Adult Spinal Deformity Surgery: A Nationwide Study With Two-Year Follow-up.

STUDY DESIGN: Cohort study. OBJECTIVES: To report the two-year revision risk following primary adult spinal deformity (ASD) surgery, describe reasons for revisions, and assess risk factors for revision surgery. SUMMARY OF BACKGROUND DATA: Revision risk following primary ASD surgery has been reported to vary between 7% and 26%, but with loss to follow-up as a considerable challenge. METHODS: Patients ≥18 years of age undergoing primary instrumented surgery for ASD in Denmark during 2006-2014 were identified by procedure and diagnosis codes in the Danish National Patient Registry (DNPR). Complete two-year follow-up on revision surgery for each patient was achieved. Medical records were reviewed to determine reasons for revisions. Overall comorbidity was summarized using the Charlson Comorbidity Index (CCI) based on DNPR data; low comorbidity (CCI 0); medium comorbidity (CCI 1-2); and high comorbidity (CCI ≥3). Risk factors for revision were assessed in a Cox regression model. RESULTS: A total of 553 patients were identified. Of these, 19.9% were revised within the two-year follow-up and 7.2% of patients were revised more than once. Median time to revision was 308 days (interquartile range 105-508). The most common reason for revision was implant failure (38.2%) followed by infection (11.8%). Increased age (hazard ratio [HR] = 1.13, 95% confidence interval [CI] 1.01-1.26, per 10 years increment) and high comorbidity burden (HR = 2.10, 95% CI 1.16-3.79) were associated with increased revision risk. Risk of revision increased from 2006 to 2014; hence, year of primary surgery (with 2006 as reference) was associated with increased revision risk (HR = 1.09, 95% CI 1.01-1.18). CONCLUSIONS: The revision risk within 2 years after primary ASD surgery was 19.9% nationwide in Denmark, and implant failure was the most common reason for revision. Increased comorbidity and age were separately associated with increased risk of revision. LEVEL OF EVIDENCE: Level II.

Readmissions, Length of Stay, and Mortality After Primary Surgery for Adult Spinal Deformity: A 10-Year Danish Nationwide Cohort Study.

STUDY DESIGN: Cohort study. OBJECTIVE: To report outcome after primary surgery for adult spinal deformity (ASD), and assess risk factors for extended length of stay (extLOS) and readmission within 90 days. SUMMARY OF BACKGROUND DATA: Complications after ASD surgery have been reported in 20% to 50% of patients. A few studies have focused on detailed information concerning postoperative morbidity. METHODS: Patients >18 years undergoing primary instrumented surgery for ASD in Denmark in the period 2006 to 2016 were included. Patients were identified in the Danish National Patient Registry (DNPR) using procedure codes for instrumented spine surgery combined with diagnosis of spinal deformity. Information on length of stay (LOS), readmissions, and mortality were retrieved from the DNPR. Medical records were reviewed for causes of extLOS (LOS >10 days) and readmission within 90 days after surgery. Charlson Comorbidity Index (CCI) was calculated for all patients based on DNPR. RESULTS: We included 892 patients. Median LOS was 8 days (interquartile range, IQR, 7-11). A total of 175 (28.0%) patients had extLOS; 81% because of "medically" related complications. Most common medically related reason (>50%) for extLOS was pain/mobilization difficulties. The 90-days readmission risk was 13.8%; 74.5% of readmissions were "medically" related, primarily opioid related side effects (18.2%), and pain/mobilization issues (15.2%); 25.5% of readmissions were "surgically" related and 16.7% of patients required revision surgery. Ninety-days mortality was 0.9%. Age groups 61 to 70 years, >70 years, CCI score 1 to 2 and CCI score ≥3 were associated with increased risk of extLOS (odds ratio, OR = 1.79, 2.01, 1.81, and 2.49, respectively). Age group >70 years and CCI score 1 to 2 were associated with increased risk of readmission (OR = 2.21 and 1.83). CONCLUSION: Increasing age and comorbidity were associated with increased risk extLOS and readmission. Pain/mobilization difficulties were the most common postoperative complications. A future focus on early mobilization and pain management may improve outcome of ASD patients. LEVEL OF EVIDENCE: 3.

Microbiological diagnosis in revision of infected knee arthroplasties in Denmark.

BACKGROUND: Revision of infected knee arthroplasties is associated with high failure rates (30-40%). An understanding of the microbiology is important to optimize treatment and outcome. We describe microbiological diagnostic practice and diagnosis in revision of infected knee arthroplasties. METHODS: One hundred and two partial revisions (open debridement and exchange of tibial insert) and 213 two-stage procedures performed due to infection in 275 patients from 1 July 2011 to 30 June 2013 were included and analysed by linkage to data from a nationwide registry on microbiological test results. RESULTS: 78 (24.8%) revisions were culture negative, 192 (60.9%) showed monomicrobial growth and 43 (14.3%) polymicrobial growth. Staphylococcus aureus was the most frequent isolate in mono-culture in 70 (22.2%) revisions and in polymicrobial culture in 15 revisions with a total frequency of 27.0%. Only one case (1.4%) of methicillin-resistance was registered. Coagulase-negative staphylococci (CoNS) were frequent, sole pathogen in 65 revisions and in polymicrobial cultures in 28 revisions with a total frequency of 29.5%. A pre-operative knee aspiration was performed in 50% and preoperative blood cultures were performed in 22% of cases. In 73% of the preoperative knee-aspirations bacteriological findings were fully or partially in accordance with intraoperative cultures. In 54% of the later re-revisions due to infection (treatment-failures) the cultured species differed from or was not detected at index revision surgery. CONCLUSIONS: The 25% culture negative cases in combination with only 50% preoperative knee aspirations and prevailing high failure rates confirm the need for improvement of diagnostic practice and treatment of infected knee arthroplasties.

Postoperative Morbidity and Discharge Destinations After Fast-Track Hip and Knee Arthroplasty in Patients Older Than 85 Years.

BACKGROUND: Elderly patients are at risk of increased length of hospital stay (LOS), postoperative complications, readmission, and discharge to destinations other than home after elective total hip arthroplasty (THA) and total knee arthroplasty (TKA). Recent studies have found that enhanced recovery protocols or fast-track surgery can be safe for elderly patients undergoing these procedures and may result in reduced LOS. However, detailed studies on preoperative comorbidity and differentiation between medical and surgical postoperative morbidity in elderly patients are scarce. The aim of this study was to provide detailed information on postoperative morbidity resulting in LOS >4 days or readmissions <90 days after fast-track THA and TKA in patients ≥85 years. METHODS: This is a descriptive, observational study in consecutive unselected patients ≥85 years undergoing fast-track THA/TKA. The primary outcome was the causes of postoperative morbidity leading to an LOS of >4 days. Secondary outcomes were 90-day surgically related readmissions, discharge destination, 90-day mortality, and role of disposing factors for LOS >4 days and 90-day readmissions. Data on preoperative characteristics were prospectively gathered using patient-reported questionnaires. Data on all admissions were collected using the Danish National Health Registry, ensuring complete follow-up. Any cases of LOS >4 days or readmissions were investigated through review of discharge forms or medical records. Backward stepwise logistic regression was used for analysis of association between disposing factors and LOS >4 days and 90-day readmission. RESULTS: Of 13,775 procedures, 549 were performed in 522 patients ≥85 years. Median age was 87 years (interquartile range, 85-88) and median LOS of 3 days (interquartile range, 2-5). In 27.3% procedures, LOS was >4 days, with 82.7% due to medical causes, most often related to anemia requiring blood transfusion and mobilization issues. Use of walking aids was associated with LOS >4 days (odds ratio [OR], 1.99; 95% confidence interval [CI], 1.26-3.15; P = 0.003), whereas preoperative anemia showed borderline significance (OR, 1.52; 95% CI, 0.99-2.32; P = 0.057). Thirty-eight patients (6.9%) were not discharged directly home, of which 68.4% had LOS >4 days. Readmission rates were 14.2% and 17.9% within 30 and 90 days, respectively, and 75.5% of readmissions within 90 days were medical, mainly due to falls and suspected but disproved venous thromboembolic events. Preoperative anemia was associated with increased (OR, 1.81; 95% CI, 1.13-2.91; P = 0.014) and living alone with decreased (OR, 0.50; 95% CI, 0.31-0.80; P = 0.004) risk of 90-day readmissions. Ninety-day mortality was 2.0%, with 1.0% occurring during primary admission. CONCLUSIONS: Fast-track THA and TKA with an LOS of median 3 days and discharge to home are feasible in most patients ≥85 years. However, further attention to pre- and postoperative anemia and the pathogenesis of medical complications is needed to improve postoperative outcomes and reduce readmissions.