Are the Cumulated Ambulation Score and Risk Assessment and Prediction Tool useful for predicting discharge destination and length of stay following total knee arthroplasty?

Postoperative management of patients undergoing total knee arthroplasty (TKA) is continually changing. Costs related to TKA are driven by implant cost, operating room cost, hospital length of stay (LOS), and rehabilitation approach. Discharges to rehabilitation centers have declined significantly in recent years. We evaluated the usefulness of the Cumulated Ambulation Score (CAS) and Risk Assessment and Prediction Tool (RAPT) to predict discharge destination and estimate hospital LOS of patients undergoing TKA. Prospective cohort study. University hospital inpatients. Patients undergoing elective primary TKA. Consecutive patients were prospectively evaluated. Outcome measures were discharge destination and LOS dichotomized at the median (LOS<8 versus LOS≥8). Patients completed five outcome questionnaires and knee range of motion was measured preoperatively. RAPT was considered continuous, and also dichotomized (RAPT≤9 versus RAPT>9; RAPT9). CAS was dichotomized (CAS<11 versus CAS≥11; CAS11). Surgical technique and aftercare were similar for all patients. Sixty-four patients (37 females), mean age 69.3±10.2 years were evaluated. CAS11 and discharge destination were strongly associated: 75.9% of patients with CAS≥11 were discharged home; 85.7% of patients with CAS<11 were discharged to a rehabilitation center (P<0.001). 80.7% of patients with RAPT≤9 were discharged to a rehabilitation center, versus 36.4% of patients with RAPT>9 (P=0.002). Odds ratios for discharge home were 18.9 (CAS11) and 7.3 (RAPT). CAS11 and RAPT were not related to LOS. The CAS and RAPT can assist clinicians in estimating the discharge destination and developing patient care plans following TKA. However, predicting LOS with such tools alone was inaccurate. Use of the CAS and RAPT can inform discharge destination and patient care plans following TKA and has the potential to optimise resources and costs. However, due to social and organizational constraints on discharge, predicting LOS with such tools alone revealed to be inaccurate