OP1.2 Parameter Optimization for Best Visualization and Complication Reduction in Hip Arthroscopy for Femoroacetabular Impingement Syndrome

Introduction: Success of technically challenging hip arthroscopy for femoroacetabular impingement syndrome (FAIS) with demanding (steep) learning curve and increased risk of complications critically depends on optimal intraoperative visualization. Studies on optimization of surgeon-controllable parameters do not exist. Thus, impact of systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial pressure (MAP), pump pressure (Ppump), intraarticular pressure (Preal), and irrigation fluid flow rate (Flow) on visibility and typical intra-/postoperative complications (fluid extravasation, pain) was assessed, also in the context of arthrosis.

Methods: Two hip arthroscopists (Expert/Advanced) evaluated visualization conditions (1-2 good/3-5 poor) at 10 typical surgical steps central/peripheral during supine FAIS arthroscopy (prospective consecutive monocentric single-surgeon cohort level 2 study, 211 patients). Influence of SBP, DBP, MAP, Ppump (inflow/outflow-system, DualWave Arthrex), Preal, Flow, arthrosis (Tönnis) on visualization, fluid extravasation (thigh circumference/swelling, linear regression) and pain (VAS, logistic regression) were analyzed. 11,403 perioperative measurements. Quantitative characteristics: Median and 1st/3rd quartile (Q1-Q3), Mann-Whitney U-test. Qualitative characteristics: Spearman’s rank correlation coefficient (ρ), 95% confidence interval = [CI]. ROC curves [95% CI]. A priori power analysis. Significance level α=0.05, Software R 4.2.2.

Results: Cut-off values/discriminatory ability (AUC [95% CI]) for good visualization across all time points (p<0.001): SBP 104mmHg/AUC 0.89 [0.87-0.91], DBP 56mmHg/AUC 0.76 [0.72-0.80], MAP 78mmHg/AUC 0.85 [0.82-0.88], Ppump 47mmHg/AUC 0.58 [0.54-0.62], Preal 44mmHg/AUC 0.71 [0.68-0.75], Flow 199ml/min/AUC 0.71 [0.67-0.75]. Blood pressure visualization excellent (grade 1): 91(87-95)/50(46-54)/68(65-72) mmHg vs. poor (grade 5): 127(119-137)/70(65-79)/94(89-98) mmHg. Preal visualization excellent: 53(46-60) mmHg vs. poor: 39(27-52) mmHg. Strong correlation (p<0.001) between visualization and fluid extravasation (ρ 0.59 [0.50-0.67] and pain (ρ 0.60 [0.50-0.68]). Significant increase of complications (p<0.001) with higher SBP/MAP/Flow (fluid extravasation) and SBP/MAP (pain). SBP in fluid extravasation low 94(89-103) mmHg vs. high 106(98-115) mmHg. SBP in pain low 94(89-102) mmHg vs. moderate to high 105(96-113) mmHg. Strong association (p<0.005) between grade of arthrosis and visualization (OR 2.37 [1.30-4.38]), fluid extravasation (OR 2.54 [1.44-4.50]) and pain (OR 2.95 [1.67-5.28]). Mean Difference Preal/Ppump 12mmHg.

Conclusion: Blood pressure (especially SBP) followed by Preal/Flow and by Ppump demonstrate significant influence on visualization at all stages of hip arthroscopy. Ideal cut-off values appear to be blood pressure 104/56/78mmHg, intraarticular pressure 44mmHg, flow 199ml/min, pump pressure 47mmHg. Good visualization and low blood pressure/flow significantly reduce complication rate. Arthrosis > Tönnis 1-2 is associated with reduced visualization and increased complications. Optimal parameters in hip arthroscopy should be prioritized for patient well-being, complication-free outcomes, outpatient feasibility, and shortening the learning curve. Intelligent interactive arthroscopy towers using such data may follow.