Hip pain referral patterns in patients with labral tears: analysis based on intra-articular anesthetic injections, hip arthroscopy, and a new pain "circle" diagram.

BACKGROUND: Fluoroscopically guided intra-articular (FGIA) anesthetic hip joint injections have been used to determine whether the hip joint is the source of a patient's hip pain. However, there have been no reports documenting the efficacy of their use for defining the pain referral patterns (PRPs) of patients with labral tears. The aim of this study was to determine the PRPs of patients with labral tears and evaluate a new pain "circle" diagram (PCD) developed for this analysis.

METHODS: Fifty-two patients were evaluated at our institution who had: 1) a preoperative FGIA anesthetic hip joint injection; 2) completed our PCD and a visual analog pain scale pre- and postinjection; 3) significant (≥ 80%) pain reduction after their FGIA injection; and 4) a labral tear and minimal (≤ grade II) degenerative joint disease, as documented by hip arthroscopy. The PCD had circles in which patients put an "X" in to indicate pain in the following locations: anterior superior spine, lateral peritrochanteric area, central groin, symphysis pubis, proximal inner thigh, anterior thigh, posterior iliac crest, sacroiliac joint, sciatic notch, and ischial tuberosity.

RESULTS: Based on the percentage of patients with significant (≥ 80%) pain reduction after administration of FGIA, 2 areas demonstrated substantially more and consistent presence of pain, which improved after injection. These were the central groin (P < 0.001) and the lateral peritrochanteric area (P = 0.02).

CONCLUSION: The most common locations of pain were the central groin and the lateral peritrochanteric area. The least common were the ischial tuberosity and the anterior thigh, which are 2 areas often associated with osteoarthritis of the hip. The use of the PCD combined with an FGIA anesthetic injection may help physicians reconcile the expectations of those patients with labral tears who believe that hip arthroscopy will treat their multiple areas of "hip" pain.