Amongst patients who are discharged home from hospital on the same day as their elective Primary Total Hip Arthroplasty, the Investigators seek to quantify the incidence of return to hospital within 30 days of surgery for assessment &/or treatment of surgical related problems or complications. This incidence rate will be compared to a cohort of patients who are not discharged on the same day as their Primary Total Hip Arthroplasty. The Investigators wish to know if the incidence of 30 day return to hospital is significantly different between these two groups of patients.

At UBC Hospital, a program to facilitate same day discharge of elective Primary Total Hip Arthroplasty patients was developed in 2017/18. The program is called the "Short Term Accelerated Recovery" (STAR) program, and patients within the program are called "STAR Patients." The first patient in the program had their surgery on Oct 15, 2018, and the program has been running ever since.

The STAR process begins by the attending surgeon (there are 5 Arthroplasty Surgeons at UBC involved in this program) earmarking a patient as a potential same day discharge candidate based on their assessment of the patient. Following this, the patient is assessed by both Physiotherapy and Anesthesia to either confirm or reject their STAR eligibility.

STAR eligibility criteria can be divided into both Social and Clinical requirements. The Social requirements are for the patient to live within an hour's drive of the Vancouver General Hospital (VGH) Emergency Room, and that they have a support person (either family or friend) that will stay with them in their home for at least the first 24 hours following surgery and can be called upon at any time subsequent to help in caring for the patient or facilitating their return to hospital if needed.

Strict Clinical Requirements to be STAR Eligible were established by the Dept of Anesthesia based on best evidence and expert opinion. These criteria were used to establish a "Check-List" of items to ensure all eligibility criteria are met. Items on this Checklist included the correct Surgical Procedure, patient age ≤ 75, Pre-Anestheic Risk Assessment, and Lab Result Reviews.

Patients initially enrolled in the STAR Program by their Orthopedic Surgeon at the time of surgical booking [presently a total of 87 patients] could end up in one of three possible cohorts following their surgery:

1. The patient was deemed STAR eligible preoperatively, had their hip replacement surgery and went home the same day as their surgery [presently 24 patients].
2. The patient was deemed STAR eligible preoperatively, had their hip replacement surgery but were NOT sent home same day as their surgery for failing to meet criteria for safe discharge and thus staying a minimum of one overnight in hospital [presently 24 patients].
3. The patient was deemed NOT eligible for STAR prior to their surgery, and therefore stayed at least one night in hospital following their surgery [presently 39 patients].

Thus far, the STAR program has failed to adequately assess the incidence of 30 day post-surgical complications. Despite an infrastructure to attain this quality assessment being in place by way of a postoperative survey sent to patients via Email, return of these surveys has been minimal thus far. As a result, the Investigators are seeking a more robust and comprehensive search of postoperative hospital encounters for surgically related problems amongst these patients by way of chart review.

This project is a retrospective cohort quality assurance chart review study. Given that the criteria for enrollment in STAR is site specific and has not been established before, this project is designed to be both a preliminary safety assessment and also able to inform future prospective studies on the program's safety for potential sample sizes needed for such assessments. As well, the study would also expose the potential for a higher than expected return to hospital for same day discharge patients which may not otherwise have been known.

A log of all patients initially enrolled as potentially "STAR Eligible" by their surgeon has been maintained by the PI. Using this list of patients, the following sequence of events will occur to assess each for hospital encounters for surgical related problems, inquiries or complications during the 30 days immediately following surgery:

1. All patient's charts, both paper records at VGH and UBC Hospital, as well as electronic charts within the BC Care Connect network that can show encounters at hospitals throughout the province of British Columbia, will be retained by Research Personnel.

2. Charts will be perused for any hospital encounters during the 30 days immediately post the date of surgery.

3. If encounters are found, the specific nature of the encounter will be ascertained.

4. Study personnel will decide, based on the clinical presentation and documentation available on the patient's chart, whether the encounter may be considered a "surgically related problem, inquiry or complication".

   Examples of surgically related problems include (but are not limited to) wound or surgical site infection, deep vein thrombosis, pneumonia, urinary tract infection, pain issues as a result of having surgery, failure or concerns for the function of the new prosthesis, trauma or falls as a result of reduced mobility following surgery.

5. Some encounters may be obvious as surgically related problems - eg. concerns for a possible wound infection at the surgical site. Others may be less obviously surgically related depending on the presentation - eg. sepsis or organ failure. It will be left to the PI to invigilate and decide whether the reasons for hospital encounter are or are not obviously surgical in nature. For those deemed not obviously surgical, opinion will be sought from 2 independent specialists in Perioperative Internal Medicine on whether they feel the encounters to be related to the patient's hip arthroplasty. Reviewers will be blinded to each other's opinions. If both Reviewers agree that the encounter was for a surgically related problem then it will be tallied as such. If there is disagreement or both believe the problem to not be surgically related then it will not be considered a surgically related hospital encounter.

6. If a hospital encounter is found amongst the patient's records, but no documentation about the nature of the encounter is available, then the Patient's Orthopedic Surgeon will be contacted to see if they retain any record of postoperative up to 30 day encounters and what the nature of the encounter was. Patients will NOT be contacted for the purpose of this QA study.

Approval for this study has been attained from the following:

1. University of British Columbia Research Ethics Board.
2. Vancouver Coastal Health Research Institute.

Study Personnel who will be retaining and invigilating patient charts will be the PI - a staff Anesthesiologist, a Resident in the UBC Anesthesiology Post-Graduate Program, and a UBC Medical Student.

It is anticipated that between 100 and 150 patients will have been through the STAR process at the time retrospective chart review begins.

Inclusion Criteria:

• Surgical Team submits patient as potentially eligible for Same Day Discharge at the time of surgical booking.

Exclusion Criteria:

• Excluded if the patient never has a surgical procedure despite surgical booking and preoperative assessment. All patients must undergo surgery to be included.

Patients with hip joint pathology being booked for elective joint replacement by Orthopedics and earmarked by the surgeon as potentially Same Day Discharge eligible at the time of surgical booking.