Radiographic Prevalence of Symphysis Pubis Abnormalities and Clinical Outcomes in Patients With Femoroacetabular Impingement Syndrome

Background: The decreased hip range of motion seen in femoroacetabular impingement syndrome (FAIS) may lead to compensatory increased motion at the symphysis pubis (SP) with resultant increased stress on the joint, which can subsequently lead to osteitis pubis.

Purpose: To quantify the prevalence of SP abnormalities in patients with FAIS through the use of imaging modalities and to compare outcomes based on the presence of SP abnormalities.

Study design: Cohort study; Level of evidence, 3.

Methods: Radiographs and magnetic resonance imaging (MRI) scans of 1009 consecutive patients who underwent primary hip arthroscopy for FAIS from January 2012 to January 2016 were identified. Exclusion criteria were patients undergoing revision or bilateral surgery, patients with dysplasia, and patients with less than 2-year follow-up. On radiographs, SP joints were reviewed for joint surface erosions, subchondral sclerosis and cysts, and ankylosis. MRI scans were reviewed for marrow edema in the subarticular pubic bone, subchondral sclerosis and cysts, joint surface erosions, and ankylosis. Patients with SP abnormalities were matched 1:2 to patients without SP abnormalities by age and body mass index. Outcomes included the Hip Outcome Score-Activities of Daily Living (HOS-ADL), HOS-Sports Subscale (HOS-SS), modified Harris Hip Score (mHHS), International Hip Outcome Tool-12 (iHOT-12), and visual analog scales (VAS) for pain and satisfaction.

Results: 830 patients were included; 23 (2.8%) demonstrated SP abnormalities. Of the 726 (72%) MRI scans reviewed, 15 (1.8%) showed bone marrow edema, subchondral sclerosis, erosions, or ankylosis. After matching, patients without SP abnormalities had significantly greater HOS-ADL (95.7 vs 83.0; P = .008), HOS-SS (91.6 vs 61.9; P = .003), iHOT-12 (89.5 vs 74.6; P = .046), and VAS satisfaction (91.3 vs 58.8; P = .004) scores, in addition to less postoperative pain (6.3 vs 23.5; P < .001). No significant differences were found in the mHHS (92.5 vs 82.2; P = .08). Patients without SP abnormalities had higher odds of achieving the minimal clinically important difference for the HOS-ADL (odds ratio [OR], 4.5; 95% CI, 1.3-14.1; P = .010), the HOS-SS (OR, 7.2; 95% CI, 1.8-18.5; P = .006), and the mHHS (OR, 14.5; 95% CI, 1.8-24.7; P = .013).

Conclusion: A low prevalence (1.8%-2.6%) of SP joint abnormality is seen on imaging in patients with FAIS. These patients may demonstrate significantly inferior clinical outcomes and persistent postoperative pain after FAIS treatment.