In the selection process, choosing patients with appropriate motivation for early discharge is essential [6, 21, 22]. Lack of awareness and low level of confidence in DCA within the patient cohort populations has been shown to be a barrier to allocate otherwise eligible patients to SDD [23]. Our experience was consistent with these findings, high proportion of potential hip and knee replacement patients were unaware of and reluctant to accept the day case option when seen at pre-operative assessment. For this reason, we only selected those from medically eligible patients for the DCA pathway who showed strong motivation and family support to go home the same day.
The overall SDD rate was 83 % and knee arthroplasties had higher rates (88% for TKA and 89% for UKA) than THAs (76%). Postoperative pain was well controlled in each group and was an uncommon reason of failure to discharge (1 patient only). This observation is somewhat contradictory to previous publications which have reported pain and lack of mobilization to be significant obstruction to early discharge of knee replacements [24, 25]. Potential explanation for this difference may be that these studies did not use adductor (Hunter`s) canal block for knee arthroplasties which was part of our protocol. It resulted in excellent pain control without motor deficit and allowed for early mobilization. The most important medical reason for overnight stays was orthostatic hypotension exclusively in THA group which is a well-documented untoward event during postoperative mobilization of hip arthroplasties. [26, 27]. The lack of this phenomenon in cases of knee arthroplasties may be another factor that explains better SDD rate of knees in our series in contrast to previous studies [8, 28].
Our SDD rates are in line with the published rates of unplanned overnight stays which range from 75% to over 99%. [29–32].
Readmissions comprised 3% of DCAs consistent with recent European studies [16] as well as with reports published on large overseas patient cohorts [4, 17, 33–35]. There was only one readmission (0.6%) due to a serious complication; a TKA patient with partial pulmonary embolism 7 days after index procedure. This patient had been mobilized per protocol, had no preoperative risk factor for VTE and our root cause analysis could not identify association with SDD. Within 24 hours, we had one readmission for wound ooze while the rest of hospitalisations were unrelated to SDD as similar causes, like suspected SSI, commonly warrant repeated admissions with inpatient arthroplasties as well [36].
In addition to low readmission and complication rates, day cases were associated with very high satisfaction rates (98%) which indicates that our outcomes are consistent with the overwhelming majority of reported case series and meta-analysis and support the opinion that DCA is feasible, safe and highly satisfactory option for suitable patient cohorts in both outpatient and inpatient settings [3,12–14,16,32,37,38).
Another affirmative consequence of DCAs treated in the arthroplasty ward was the shortening of LOS over the entire cohort of patients within the traditional inpatient pathway. Shortening of hospital stay with arthroplasties has been a general trend worldwide [39, 40], but the observation of a rapid, simultaneous reduction in LOS with the increase of DCA patient cohort has not been reported before. Prior to introduction of SDD and during the low volume pilot phase, rate of 1-night stays was constantly approximating 15%, with inpatient LOS at 2.3 days. In parallel with the surge of DCA numbers, fast increase of next day discharges to 60% and decrease of LOS to 1.8 days on the inpatient pathway was noticed and maintained during the entire observation period even when day case numbers dropped considerably because of Covid capacity restrictions. (Figs. 1,2 and 3) The strong correlation was verified by Pierson coefficient as well. Outpatient-based arthroplasty has been reported more time efficient, patients spend about 30% less time in the unit compared to day cases treated at an inpatient ward. Apart from differences in comfort conditions and the higher staff-patient ratio, this is generally attributed to attentive teams working fully focused toward early discharge at a separated outpatient department [14, 18]. In our ward set up, we assigned dedicated but non-exclusive staff to treat day cases and eventually our entire ward team became skilled in and confident with the day case rehabilitation protocol. The inevitable split of attention of shared medical and physiotherapy teams may have slightly extended hospital stay of day cases with a few hours but appeared to boost earlier discharges on the inpatient pathway. As the main differences in postoperative rehabilitation were swifter mobilization, more intense and time-sensitive medical observation of day cases, we hypothesize that success of SDD protocol inspired the ward teams to adopt similar practices on the inpatient pathway thus helping medically fit patients achieve discharge criteria earlier. On the other hand, a larger subset of inpatients may have felt empowered to engage with fast-track regime by witnessing first-hand the rapid progression of day cases. It appears that supplementing our physiotherapy and medical team skills with day case management routine has improved their efficacy and contributed to acceleration of inpatient recovery.
We believe that this pleiotropic effect is an important observation as it demonstrates that in addition to significant financial benefits of DCA alone [15], the shortening of inpatient stay may offer further cost savings and capacity relief for hospitals where significant number of beds are reserved for elective arthroplasties.
Strength of our study is that, compared with the European standards, our case numbers are high, thus adding to the literature data regarding safety of SDD arthroplasty. Our study presents a new finding namely, that treating SDD patients mixed with traditional arthroplasties in the same ward may facilitate shorter hospitalisation of inpatients.
This study has weaknesses including lack of matched inpatient group and longer than 6 weeks follow up with validated outcome measures.