AJSM - 2026-08-18 - Journal Article
Higher Rates of PASS and SCB After Arthroscopic Subspine Decompression Are Associated With a Positive Diagnostic AIIS Injection: A Propensity Score-Matched Cohort Study.
Duan YP, Yang F, Liu RG, Sun H, Huang H, Xu Y, Ju XD, Wang JQ
Topics
Key Takeaway
Patients with injection-confirmed subspine impingement achieved PASS rates approximately 15–20 percentage points higher across all PRO measures compared to CT-morphology-only selection after arthroscopic subspine decompression at minimum 2-year follow-up.
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Summary
This study compared outcomes of arthroscopic subspine decompression in FAIS patients with type II/III AIIS morphology selected by CT alone versus CT plus positive ultrasound-guided AIIS injection. At minimum 2-year follow-up, the injection-confirmed group had significantly better mHHS (90.8 vs 84.2), HOS-ADL (88.4 vs 82.4), HOS-SS (71.9 vs 64.1), and iHOT-12 (83.9 vs 76.1), all P<0.001. PASS and SCB rates were significantly higher in the injection group across all PRO measures, while MCID rates were high in both groups and revision rates did not differ.
Key Limitation
The threshold and volume for a 'positive' diagnostic injection were not standardized, making the injection protocol difficult to reproduce and potentially introducing misclassification bias in the injection group.
Original Abstract
BACKGROUND
Hip arthroscopy effectively treats femoroacetabular impingement syndrome (FAIS), but persistent pain may be related to concomitant extra-articular pathology such as subspine impingement syndrome (SSI). Standard diagnosis of SSI often relies on 3-dimensional computed tomography (3D-CT) morphology (Hetsroni type II/III), although this morphology is common in individuals who are asymptomatic and correlates poorly with symptoms.
PURPOSE
To compare minimum 2-year clinical outcomes after arthroscopic subspine decompression in patients with concurrent FAIS and type II/III anterior inferior iliac spine (AIIS) morphology, stratified by diagnostic method: 3D-CT morphology alone versus 3D-CT morphology plus a positive ultrasound-guided diagnostic injection.
STUDY DESIGN
Cohort study; Level of evidence, 3.
METHODS
This study included patients aged 18 to 55 years with type II/III AIIS morphology who underwent primary hip arthroscopy for FAIS and SSI between January 2021 and November 2023 and had minimum 2-year follow-up. Patients diagnosed by CT morphology alone (CT classification group) were propensity score matched 1:1 to patients with a positive ultrasound-guided AIIS injection (injection group), with 57 patients per group. Matching variables were age, sex, body mass index, lateral center-edge angle, alpha angle, Tönnis grade, and Beighton score. All patients underwent arthroscopic subspine decompression. Patient-reported outcomes and rates of achieving the minimal clinically important difference, Patient Acceptable Symptom State (PASS), and substantial clinical benefit (SCB) were compared.
RESULTS
Preoperative patient-reported outcome scores were similar between groups (all P > .05). At minimum 2-year follow-up, the injection group had significantly better scores on the modified Harris Hip Score (90.8 vs 84.2), Hip Outcome Score-Activities of Daily Living (88.4 vs 82.4), Hip Outcome Score-Sports Subscale (71.9 vs 64.1), 12-item International Hip Outcome Tool (83.9 vs 76.1), and visual analog scale for pain (1.2 vs 2.0) (all P < .001). Minimal clinically important difference rates were high in both groups, with higher rates in the injection group for modified Harris Hip Score (93% vs 77%; P = .033) and Hip Outcome Score-Activities of Daily Living (91% vs 75%; P = .042). PASS and SCB rates were significantly higher in the injection group across all patient-reported outcome measures (all P < .05). Revision and complication rates were low and did not differ significantly between groups.
CONCLUSION
Both groups improved significantly after arthroscopic subspine decompression. However, patients with a positive ultrasound-guided diagnostic AIIS injection achieved higher PASS and SCB rates than those selected by CT morphology alone, suggesting that injection-confirmed SSI may improve patient selection for subspine decompression.