Date of Award

January 2019

Document Type


Degree Name

Medical Doctor (MD)



First Advisor

Jonathan N. Grauer


With the recent push for safe reductions in hospital length of stay (LOS) following orthopaedic procedures, increasing aging population, and new surgical technologies, the purposes of this thesis are three-fold. (1) To compare the complication profiles of patients who underwent outpatient versus inpatient total knee arthroplasty. (2) To determine the safety of performing revision total hip arthroplasty in the octogenarian patient population. (3) To establish any clinically meaningful differences between navigated versus conventional single-level instrumented posterior lumbar fusion.

The following methods were used. (1) Patients undergoing outpatient (defined as LOS = 0 days) or inpatient (defined as LOS = 1 – 30 days) total knee arthroplasty were identified from the National Surgical Quality Improvement Program (NSQIP) database and their perioperative outcomes were compared. (2) Patients who underwent aseptic revision total hip arthroplasty were identified from the NSQIP database and stratified into two age groups: <80 and ≥80 years old. Multivariate regressions were used to compare risk for postoperative complications and readmission between the two age groups. (3) Patients who underwent navigated or conventional single-level posterior instrumented lumbar fusions were identified in the NSQIP database. The usage of navigation was characterized. Propensity score matching was done and comparisons were made for operative time, hospital length of stay, postoperative complications, and thirty-day readmissions between the two cohorts.

Findings were as follows. (1) After propensity matching, multivariate analysis revealed a higher rate of post-discharge blood transfusions (p<0.001) in the outpatient total knee arthroplasty cohort. There were no other significant differences in 30-day postoperative individual adverse events or readmissions. (2) Multivariate analysis revealed higher risk for perioperative mortality, pneumonia, urinary tract infection, blood transfusion, and extended length of stay in ≥80 compared to <80 year olds. (3) After propensity matching to control potential confounding factors, statistical analysis revealed no significant difference in operative time and for most adverse events including wound infection, return to the operating room, and readmission. There were significantly lower blood transfusions in the navigated cohort (2.84% versus 7.15%, p<0.001).

Conclusions are as follows. (1) Based on the perioperative outcome measures studied here, outpatient total knee arthroplasty can be appropriately considered in select patients based on rates of overall perioperative adverse events and readmissions. However, higher surveillance of these patients post discharge may be warranted. (2) Even after controlling for patient and procedural characteristics, aseptic revision total hip arthroplasty in ≥80 year olds is associated with greater risks than their younger counterparts. This is important for counseling and highlights the need for medical optimization in this vulnerable patient population. (3) The lack of differences in most perioperative outcomes suggest that the use of navigation should be guided by what the surgeon feels is best in their hands to deliver the best care to their patients, as opposed to objective measures assessed here.


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