A Matched Case-Control Comparison of Hospital Costs and Outcomes for Knee Replacement Patients Admitted Postoperatively to Acute versus Subacute Care

The Perioperative Surgical Home (PSH) is designed to provide a coordinated, patient-centered approach to surgical care. At one university-affiliated Veterans Affairs (VA) hospital with a PSH, we established an alternate... [ view full abstract ]

The Perioperative Surgical Home (PSH) is designed to provide a coordinated, patient-centered approach to surgical care. At one university-affiliated Veterans Affairs (VA) hospital with a PSH, we established an alternate pathway in which total knee arthroplasty (TKA) patients who met medical and logistical criteria (bed availability, ASA 3 or lower, no sleep apnea, and no chronic pain or opioid use history) could be directly admitted from postoperative recovery to an on-campus subacute rehabilitation center instead of the acute care surgical ward. In this retrospective study, we examined whether this “fast track” pathway was associated with lower costs and improved patient outcomes.

We examined the medical records of consecutive patients who underwent unilateral primary TKA from July 1, 2015, through September 30, 2016. We initially collected the following data for all patients: 1) postoperative admission unit; 2) age; 3) sex; 4) height; 5) weight; 6) body mass index; and 7) ASA physical status. After including cases admitted to subacute rehabilitation, each case was matched with a control admitted to the surgical ward using baseline variables. The primary outcome was estimated total cost of hospitalization (length of stay multiplied by the average cost per day provided by the VA Managerial Cost Accounting Program for fiscal years 2015-16). Secondary outcomes were hospital length of stay (days); pain scores (0-10 numeric pain rating scale), opioid consumption (mg morphine equivalents), and maximum ambulatory distance (meters) on postoperative days 1 and 2; 30-day morbidity and mortality; and 30-day readmission rate.

There were 262 TKA patients during the study period; 14 were admitted directly to rehabilitation. These cases were matched to 14 unique patients admitted to the surgical ward. The estimated total hospitalization cost [median (10th-90th percentiles)] was $30,755 ($23,066-$38,444) for ward patients compared to $17,620 ($13,215-$33,918) for rehabilitation patients (p=0.006). This difference [mean (95%CI)] was $10,143 ($2,174-$18,112). There was no difference in length of stay or other outcomes between groups. In the postoperative period, 1 ward patient required a rapid response for suspected anaphylaxis; 2 rehabilitation patients had presyncopal or syncopal episodes (p>0.999). Within 30 days, 1 ward patient visited the emergency room for pain management without reoperation while 1 rehabilitation patient required manipulation under anesthesia (p>0.999). There were no other cases of major morbidity or death in either group at 30 days postoperatively.

For eligible patients, direct postoperative admission to a subacute rehabilitation ward may be less costly than admission to an acute care surgical ward following TKA and may not negatively affect length of stay, pain control, functional achievement, or other outcomes within 30 days of surgery. Compared with outpatient TKA, on-campus rehabilitation still allows physicians to monitor patients for complications and respond quickly although at lower cost than traditional hospitalization.