Risk Analysis of Restrictive Factors for Fast-Track Knee Arthroplasty-A Retrospective Study of 1,224 Patients

With the implementation of a fast-track principle as an interdisciplinary and multimodal concept, an accelerated convalescence and reduction of postoperative complications and a reduction of hospital stay can be achieved. This has been shown not only to increase patient satisfaction but in reduction of hospital cost as well. However, the concept cannot be successfully implemented in all patients. Patients who require an extended length of stay (LOS) after surgery can profit from optimizations of postoperative care and rehabilitation as well. Therefore, early identification of such patients is desirable. This case control study aimed to identify patient characteristics and patient-independent factors that may affect fast-track programs and lead to extended length of stay in knee arthroplasty.

From October 2007 to May 2013, 1224 patients were treated at the University Hospital Halle (Saale) with a total knee arthroplasty (TKA). A maximum stay of seven days was defined as the target of the "fast-track arthroplasty" concept. There were 164 patients (13%) that did not reach this timeframe and were assigned to the case group (n=164). Each case group patient was compared to a patient with an inpatient stay of seven days or less who was operated on the same day and by the same surgeon. These patients formed the control group (n=164). In addition to causes for extended LOS, metadata (age, sex, body mass index [BMI]), chronic nicotine and alcohol abuse, American Society of Anesthesiology (ASA) score, blood transfusion necessity, and comorbidities were determined. The statistical analysis included two sample t-tests, a chi-square test, and logistic regression analyses. Additionally, 95% confidence intervals were calculated (p<0.05).

Gender distribution in both groups showed no differences (case group: 40.2% male, 59.8% female vs. control group: 32.3% male, 67.7% female). The ø age in the case group was 69.6 ± 8.7 years, significantly higher than that of the control group with 66.5 ± 9.4 years (p=0.002). Another difference between the groups was seen in the need for red blood cell transfusion (case group 51.2%, control group 39.6%, p=0.03). The need for postoperative antibiotic therapy was associated with a 3.741-fold risk of prolonged hospital stay. ASA score and BMI were identical in both groups. For the patients with positive nicotine abuse, the regression analysis showed a 2.465-fold risk of prolonged length of stay. Alcohol abuse did not appear to play a role in length of stay in our patient cohort. For pre-existing conditions, patients from the case group were more likely to have a cardiac burden than those from the control group (p=0.03). The most common causes of prolonged LOS were elevated CRP followed by effusion and delayed wound healing.

The study shows that especially patient age, the presence of cardiac secondary diseases, nicotine consumption, and patient-independent factors like blood loss could have a negative influence on convalescence. Despite constant cost reductions in the healthcare system, the concept of "fast track arthroplasty" should always be adapted to the specifics of each individual patient in view of increasing patient age or critically questioned already preoperatively.