Arthroscopic Subspine Decompression Is Commonly Reported in a Heterogenous Patient Population With Concomitant Procedures: A Systematic Review.

Purpose: To systematically review the evaluation, management, and surgical outcomes of arthroscopic subspine decompression in conjunction with other intra-articular hip preservation procedures.

Methods: Two databases (PubMed and Embase) were searched from 2010 to 2021, in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, for articles investigating arthroscopic subspine decompression using the key words: "subspine impingement", "AIIS impingement", and "extra-articular impingement." Exclusion criteria included diagnostic studies, failure to report postoperative outcomes, and case series of less than 10 hips. Studies were assessed for patient demographics, diagnostic criteria, clinical findings, concomitant procedures, outcomes, and postoperative complications. The quality of the studies was analyzed by 2 independent reviewers (A.J.C. and A.E.J.) using the Methodological Index for Non-randomized Studies (MINORS).

Results: Ten studies consisting of 438 patients (460 hips, 48.6% female) met the inclusion criteria, with average ages and follow-up ranging from 24.9 to 34.7 years and 6.0 to 44.4 months, respectively. There was 1 Level II study, 3 Level III studies, and 6 Level IV studies. The MINORS criteria yielded an average quality assessment of 13.0 (range: 7-22), with 3 methodological domains demonstrating mean scores of less than 1: unbiased assessment of the study endpoint (.25), loss of follow up less than 5% (.25), and prospective calculation of the study size (.7). The most common exam maneuver used was the subspine impingement test (9 studies). Most subspine decompressions were performed in addition to traditional femoroacetabular impingement syndrome (FAIS) procedures, with only one study (33 hips) reporting solely on isolated subspine osteoplasty. Average preoperative and postoperative modified Harris Hip Score (mHHS) values ranged from 44.93 to 75.7 and 79.5 to 98.0, respectively. Three studies noted improved hip flexion in the postoperative period. Five surgical complications were reported.

Conclusions: Arthroscopic subspine decompression is commonly reported in a heterogenous patient population with intra-articular hip pathology. A combination of the subspine impingement test and anterior inferior iliac spine (AIIS) morphology on imaging is frequently used for diagnosis. While improved patient-reported outcomes (PROs) are consistently observed following arthroscopic decompression, conclusions are limited by study methodology and concurrent procedures performed at the time of surgery.

Level Of Evidence: IV, systematic review of Level II through Level IV studies.