Poster 191: Does Ischemic Preconditioning of the Operative Limb Reduce Pain after Hip Arthroscopy? A Prospective, Single Blind, Randomized Controlled Trial
Authors: Orner Caitlin , Usoro Andrew , Bergeron Brooke , Banffy Michael 
Published: August 2024

Objectives:

Improving pain control after hip arthroscopy is an important concern for surgeons and for optimizing the patient experience. Many surgeons use multimodal protocols including peripheral nerve blocks, oral medication, and intra-articular or local anesthetic. Identifying additional preoperative modalities for pain management is a promising way to improve pain and potentially decrease narcotic use. Ischemic preconditioning (IPC) involves the exposure of brief periods of circulatory occlusion and reperfusion which has protective effects on muscular and organ tissues. In addition, studies on the use of IPC prior to knee surgery have shown improvements in postoperative pain and decreased opioid consumption. The purpose of this study was to determine whether preoperative IPC of the operative limb affects postoperative pain scores or opioid consumption after hip arthroscopy.

Methods:

This is a prospective, single blind, randomized controlled trial. Patients were enrolled between October 2021 and April 2023. Inclusion criteria were patients age ≥ 18 years old undergoing hip arthroscopy by a single surgeon for hip pain in the setting of femoroacetabular impingement or labral tear. Exclusion criteria were history of venous thromboembolism or patients on medications known to increase the risk of blood clots. Following informed consent, patients were randomized to the IPC or control group and were blinded to their treatment group. Limb preconditioning was performed within 24 hours prior to surgery using the Delphi Personalized Tourniquet System (PTS) with the cuff placed on the proximal thigh of the operative limb. Patients in the IPC group received a 30-minute treatment consisting of 3 rounds of 5 minutes at limb occlusion pressure (LOP) alternating with 5 minutes of reperfusion. Patients in the control group received the same protocol at 20% LOP. Hip arthroscopy was then performed according to standard of care. All patients received a standardized preoperative and postoperative pain control regimen. Surveys were administered through RedCap daily from day of surgery through postoperative day 7. Patients were asked to rate their pain 0-10 according to the visual analog scale (VAS) for pain and to record pain medication utilization. Charts were reviewed for baseline characteristics and surgical procedures. Chi-square, independent t tests and paired t tests were used for statistical analysis.

Results:

A total of 64 patients (31 in the IPC group, 33 in the Control group) were enrolled. Demographics (age, sex, and body mass index) were similar between the IPC and Control groups. There was no significant difference in surgical procedures performed. Survey compliance was higher in the IPC group compared to the control group, 6.1 ± 2.8 days vs. 3.7 ± 3.4 days, respectively (p < 0.05). Both groups reported significant reductions in their VAS for pain scores from day of surgery to postoperative day 6 or 7 (p < 0.05). There was no significant difference between the IPC and control groups in VAS for pain scores at any of the time points from day of surgery to postoperative day 7 (Figure 1). There was also no significant difference between the groups in mean daily opioid consumption (expressed as morphine milligram equivalents) or in acetaminophen consumption at any time point. There were no early complications (within first 7 days postoperatively).

Conclusions:

Limb IPC does not appear to decrease pain or medication utilization after hip arthroscopy. It is possible that the pain modulating effects of IPC are not as effective when the surgical site is proximal to the site of occlusion. Other factors may have contributed to variability in the reported VAS scores, including differences in fluid extravasation, personal pain tolerances, and utilization of pain control regimen. [Figure: see text]