Day case ankle arthroplasty: are they safe and cost effective? A single-centre case-control study

Abstract

Background

Most patients who have an ankle replacement in the United Kingdom stay in hospital for 2–4 days. This study looked at the safety & cost-effectiveness of a day case ankle replacement pathway.

Methods

This was a retrospective case-control study looking at day case pathway for ankle replacements set up in collaboration with anaesthetists, nurses and physiotherapists. Patients practiced mobilization with crutches before surgery. Patients were discharged home with enough analgesia, and reviewed within 2–5 days of discharge.

Results

Twenty ankle replacements done between November 2017 and November 2019 were reviewed with a mean follow up of 38.4 months. None of these patients required to be readmitted within the first 28 days. No complications were related to the surgery being done as day case. Except one, all patients described the experience as excellent or good.

Conclusion

Per case the cost savings are estimated to be £880 in comparison to 20 matched inpatient ankle replacements. We conclude that ankle replacements can be safely carried out as day case with appropriate patient selection, pre-operative education and a multi-disciplinary approach.

1. Introduction

Day case or outpatient arthroplasty option is being increasingly offered for all arthroplasty patients including hip and knee. Patient selection and education are key to successful day case arthroplasty protocols and should follow a multi-disciplinary approach. A few articles mostly from the United States^1,2 have confirmed the safety and cost effectiveness of outpatient ankle arthroplasty with good patient satisfaction. However, most of these papers count 23 h stay as outpatient surgery and in NHS (National Health Service, United Kingdom) day case surgery means the patient gets admitted and discharged the same day.³ Recommendations made by GIRFT (Getting It Right First Time) project have been adopted by NHS and this has helped reduce inpatient stay for joint replacements already.⁴ With severe bed shortage, inpatient elective surgery in most NHS hospitals results in last minute cancellations. Average length of inpatient stay after an ankle arthroplasty in the UK is typically between 2 and 4 days.^4,5 We are aware of only one other concurrent study looking at day case ankle arthroplasty in the UK.⁵

Our unit started offering day case ankle replacements to patients in November 2017. Our aim was to assess the safety & cost effectiveness of day case ankle arthroplasty surgeries conducted over a two-year period. Our hypothesis was that the patients undergoing day case ankle arthroplasty would have equivalent short-term outcomes and satisfaction with no readmissions in the first 4 weeks at a significantly lower cost.

2. Methods

This study complies with the local research guidelines and no patient identifiable information has been used in this study. The fellowship trained senior author had been performing ankle replacements since 2011 as inpatients in line with the standard practice. The indication for ankle replacement was end stage ankle arthritis after failed conservative treatment. The alternative option of fusion was discussed in detail with all patients before surgery. The length of stay was 2.2 days before introduction of a day case protocol in 2017. We set up a new day case pathway for ankle arthroplasty in collaboration with all stakeholders including pre-operative assessment nurses, day case ward staff, anaesthetists and physiotherapists. Consensus was reached on inclusion criteria for the day case pathway, anaesthetic techniques, pre-operative and post-operative physiotherapy inputs, post-operative analgesia and safe discharge criteria (Table 1).

Table 1.

Inclusion & Safe Discharge criteria.

Inclusion/Safe Discharge criteria

Exclusion criteria

Responsible adult to stay with overnight Able to mobilize Non-weight bearing Safe Discharge Criteria: Vital signs stable Orientated to time, place, and person Passed urine Able to dress and walk Oral fluids tolerated Minimal pain No bleeding from wound Minimal nausea and vomiting Written and verbal postop instructions Know who to contact in an emergency Follow-up appointment arranged Has take-home medications

Unable to mobilize Non-weight bearing Lives alone After Surgery: Does not meet safe discharge criteria

Since November 2017 patients who met the safe day case discharge criteria were treated as day cases and the rest of them were treated as inpatients (Only 3 patients out of 23 who had ankle arthroplasty during this period were scheduled for inpatient surgery, mostly due to pre-existing mobility issues and hence being unsuitable for safe discharge without further physiotherapy input). The change in protocol included pre-operative assessment by a dedicated pre-operative assessment team who reviewed patients against safe discharge criteria used for all day cases undertaken in the hospital. They were also given written information on day case surgery, pain management and physiotherapy. Patients also had assessment by a physiotherapist before surgery to practice non-weight bearing mobilization using crutches (patients start full weight bearing after their first post-operative visit, usually between 2nd to 5th post-operative days, when they receive a weight bearing scotch cast).

Patients were operated first on the morning operating list to give adequate time for recovery and practicing safe mobilization before discharge from Day case ward. All patients received Hintermann 3 mobile bearing ankle prosthesis (marketed by Vilex currently, this implant was formerly known as Hintegra when marketed by Integra). They received one dose of Teicoplanin and Gentamycin at induction. Tranexamic acid was given intraoperatively, and a suction drain inserted before wound closure. This drain was removed 2 h after the procedure. Patients had plaster of Paris back slab for comfort for the first few days. Patients were given Gabapentin or Tramadol for pain relief in the post-operative period along with Paracetamol/Caffeine combinations. All our patients received low molecular weight heparin (LMWH) for 6 weeks as they were deemed high risk under our local institutional guidelines. Patients were given the option to return to hospital for any issues in the immediate post-operative period including problems with pain control.

Consecutive day case ankle replacements from November 2017 were reviewed retrospectively to look at the safety and cost-effectiveness of this protocol. Emphasis was on post-operative pain relief and unplanned readmissions in the first 4 weeks which could be attributed to an early discharge. The patients were asked to simply rate their experience as - Excellent, Good, Fair or Poor. They were also asked whether they would consider the surgery to be carried out in the same manner as day case if they had to go through it again or prefer to stay in hospital for any reason afterwards. This was checked at their most recent or final face to face follow up appointment. This group was compared with a control group of similar number of inpatient ankle replacements performed by the same author in the previous years. These patients were also asked whether they would have preferred to have the surgery done as daycase instead. Patient satisfaction was correlated with age, sex, ASA (American Society of Anaesthesiologists) grade and anaesthetic technique (General or Spinal anaesthesia) using t-test and chi-squared tests with Medcalc software (version 19). A p-value of <0.05 was considered significant.

3. Results

Twenty days case ankle arthroplasties (19 patients, 19 primary and one revision) were included in this study. Thirteen males and 6 females with a mean age 66.9 years (Range 49–81 years). Most patients were ASA Grade 2 (12), 6 were ASA grade 3 and one Grade 1. Twelve out of 19 patients had used at least one stick for mobilization before surgery but went on to using two crutches or a frame during the initial post-operative period. None of the patients scheduled for daycase surgery required conversion to inpatient stay. Mean follow up of 38.4 months (Range 27–51 months) but the study only looked at 28-day readmissions and early complications during this period. One patient developed subluxation of the mobile polyethylene insert at 8th week and underwent liner exchange to a bigger size with lateral ligament reconstruction (this was also performed as a day case).

Thirteen patients described their day case surgery episode was excellent, 6 rated it as good and one rated it as fair. The patient who rated is as fair had issues with pain control as he only received Paracetamol for the first 2 days due to a pharmacy dispending error. He was prescribed Tramadol on his first follow up visit (3rd post-operative day) but he was still happy with the fact that the surgery took place on a day case basis. One patient returned two days after surgery with a tight plaster back slab which was changed by the emergency on call team with instant pain relief. She was still happy with the day case protocol and had no other post-operative complications. Two patients had delayed wound healing taking 5–6 weeks for full healing of the wounds. There were no confirmed cases of superficial or deep wound infection. All patients confirmed that they would undergo a similar procedure again on a day cases basis.

Men reported excellent satisfaction scores more frequently than women (p value 0.0223, chi-squared test). Age did not affect the outcome (p value 0.34, t-test). There was no difference between spinal anaesthesia and general anaesthesia with regards to outcome (p value 1.0, chi-squared test). ASA grade did not affect patient satisfaction (ASA grades 3/4 vs ASA 1/2, p value 1.0, chi squared test).

Twenty matched inpatient ankle replacements done over the previous 4-year period were reviewed to compare patient satisfaction and determine number of bed days saved (Table 2). They were matched for age, sex and ASA grade and hence would have been suitable for day case arthroplasty. Mean age of 68.1 years (Range 44–91 years) with 14 males and 6 females. There were no 28-day readmissions in this group. There was 100% implant survival at 64.2 months mean follow up. Mean hospital stay was 2.2 days (1–12 days range). Cost of surgery was compared between the two groups using historic reference costs published by Department of Health, UK.⁶ Based on this average cost reduction was £880 per patient (£400 × 2.2 days inpatient bed days saved per patient).

Table 2.

Day case versus Inpatient ankle arthroplasty.

Ankle arthroplasty	Day cases	Inpatients
Total number	20	20
Age in years– Mean (Range)	66.9 (49–81)	68.1 (44–91)
Sex- Male: Female	13:7	14:6
Hospital stay in nights	0	2.2
Return to Emergency department	0	0
28-day Readmissions	0	0
Delayed wound healing	2	3
Patient satisfaction Excellent/Good/Fair/Poor	13/6/1/0	14/6/0/0

4. Discussion

There has been a recent surge in the practice of day case hip, knee, and shoulder arthroplasties. Healthcare facilities in general benefit from day-case surgeries as it is less expensive (30%) with similar safety and effectiveness compared with usual admission protocols.⁷ Most elective forefoot surgeries are performed as day cases. However, following hindfoot reconstructions, fusions, and total ankle arthroplasty, patients are often admitted for 1–3 days for pain control, wound checks and physiotherapy. Such admissions come at a significant cost compared to daycase surgery. With proper patient selection, day case surgery can provide similar outcomes at a lower cost. Tedder et al.¹ looked at 66 ankle replacements done on outpatient basis and compared them with their series of inpatients. Their results suggest that both groups showed similar complications and that outpatient procedure was safe and even a superior option for most patients. Gonzalez et al.² analysed 21 patients who underwent outpatient ankle arthroplasties and found that it was a cost-effective and safe alternative with high safety profile & patient satisfaction. They suggested that with proper patient selection, outpatient ankle replacements were beneficial to both patients and the health care system at a lower cost.

From Northumbria in the United Kingdom, Drake et al.⁵ reported on their series of first 21 day case ankle replacements done from September 2017 onwards and suggested that day case Ankle Replacements are safe but appropriate patient selection is necessary and success often relies on teamwork. We started offering daycase ankle replacements around the same time (November 2017) and we have similar findings. Together these studies confirm that with appropriate patient selection, prompt education before surgery, and a proper clinical pathway, day-case ankle arthroplasty can be safely carried out at any centre currently offering these as inpatient procedures.

For hip and knee day case arthroplasty most authors have selected younger patients under 65–80 years⁸ with a lower body mass index (BMI) of less than 35–40 kg/m2 and without any significant comorbidities. Scoring systems have been proposed for assessment of suitability of patients for outpatient arthroplasty.⁹ Literature suggests that these are better than ASA scores to predict before surgery which patient is likely to go have successful same day discharge. We did not use any scoring system in our study. We chose patients based on their mobility status (those who were able to demonstrate/practice non weight bearing mobilization with physiotherapists before their surgery). Those patients who were unable to do so were asked to stay in as inpatients after surgery for more physiotherapy. All day case ankle arthroplasty patients had their post-operative plaster back-slabs changed to weight bearing scotch-casts within the first 5 days and were allowed to weight bear at that point. We agree with other authors that, it is important to confirm patients have appropriate home support in place to help them recover after surgery.¹⁰ Patient education before surgery has been shown to be key to reducing length of stay in knee replacement patients ¹¹ and is specifically important in those with anxiety about their surgery.¹²

It is controversial whether general anaesthesia or spinal anaesthesia is better choice for day case arthroplasty.¹³ Some studies have shown shorter hospital stay and lower morbidity/mortality with the use of general anaesthesia.¹⁴ Our anaesthetic colleagues felt that spinal anaesthetic delayed patient mobilization and was a deterrent to implementing a day case pathway. Hence most patients in this study (18 out of 20) had a general anaesthetic. Prevention of venous thromboembolism is best accomplished with non-pharmacological measures such as hydration, mobilization, mechanical devices and pharmacological prophylaxis.¹⁵ All our patients received a 6-week course of LMWH and none of the patients in either the day case or inpatient group had a post-operative thromboembolism episode.

Post-operative anaemia is common after hip and knee arthroplasty patients and a deterrent to early discharge. This is usually not seen after ankle arthroplasty. We used a tourniquet during surgery which is line with common practice. Since 2015 we have been using intra-operative tranexamic acid which has been shown to be an effective haemostatic agent reducing blood loss, joint swelling, and the wound complications¹⁶ and continued the practice during the day case pathway. Although the use of suction drainage has been largely abandoned by hip and knee arthroplasty surgeons¹⁷ we continue using a drain but removed it 2 h after surgery to facilitate day case discharge. Most patients drained only about 100–200 ml; however we feel that this reduces risk of hemarthrosis and wound complications which are seen commonly after ankle arthroplasty.¹⁸

Key to successful day-case surgery protocol is obtaining pain control with few side-effects as possible and best achieved with a multimodal analgesic protocol.¹⁹ Pain control after surgery was offered by a combination of oral pain medications. All our patients received either a sciatic nerve block or wound infiltration with local anaesthetic which supplemented pain relief after surgery.

There is no agreement in the literature on safe discharge criteria for day-case arthroplasty. Most discharge patients if they have safely mobilized, with normal vital signs and have adequate pain control medications to take home.²⁰ Our discharge protocol ensured that patients had adequate analgesia following surgery and their pain scores were below 3 out of 10 on visual analogue scale for pain. Most patients received either Gabapentin or Tramadol in the post-operative period which ensured adequate pain control. The only patient who described their day case surgery experience as just “fair” received only Paracetamol as his take home medication due to a dispensing error. This was rectified in his follow-up visit on the 2nd post-operative day and thereafter pain stayed under control with appropriate analgesia.

Day-case arthroplasty also have financial benefits for wider healthcare. At £400 per day⁶ an inpatient bed in NHS is a valuable commodity. By switching to day case ankle arthroplasty average cost reduction was £880 per patient (average inpatient stay of 2.2 days at our hospital before our new day case pathway was introduced).

We feel that the main limitation of this study is being a small series of patients who have undergone day case ankle replacements at a single centre by a single surgeon. However, we feel that similar pathways can be introduced to even major units with multiple ankle arthroplasty surgeons. A discussion with all stakeholders is an essential part in setting up a successful day case arthroplasty pathway.

We conclude that ankle replacements can be safely carried out as day case with appropriate patient selection, pre-operative education and a multi-disciplinary approach. Learning from successful implementation of this pathway, we now perform all elective foot and ankle procedures (ankle/hindfoot fusions, osteotomies and tendon transfers) as day case if safe discharge criteria are met.

Declaration of competing interest

None.