Femoral head infarction: a case-control study of a rare complication

Background To determine the prevalence of the femoral head infarction (FHI) following hip arthroscopy, explore potential contributing factors, and assess its influence on clinical outcomes. Methods We evaluated consecutive patients who underwent hip arthroscopy in our hospital between May 2014 and May 2023 retrospectively. Patients underwent MRI at least one year after surgery. FHI was identified as large scale edema signal at the junction of the femoral head and neck in postoperative MRI. FHI were matched in a 1:3 cohort to the normal group based on sex, age, and body mass index (BMI). Preoperative patient-reported outcomes (PROs) and PROs at least one year after surgery were obtained. Results A total of 372 patients were finally included in this study. In the MRI follow-up, it was discovered that ten patients (2.7%) had FHI. Patients in FHI group had significantly lower BMI than patients without FHI ( P = 0.008). Patients in the FHI group did not show significant improvements in postoperative mHHS, iHOT-12, or VAS scores ( P > 0.05). Patients in the FHI group demonstrated significantly lower postoperative mHHS and iHOT-12 scores, along with higher VAS scores ( P < 0.05). In the FHI group, only 3 patients (30%) surpassed the MCID and achieved the PASS for mHHS, while no patients surpassed the MCID or achieved the PASS for iHOT-12. The proportion of patients who achieved the MCID or the PASS in the normal group was significantly higher than that in the FHI group ( P < 0.05). Conclusion Our study demonstrated that FHI could be a rare complication following hip arthroscopy. Patients with lower BMI are at a higher risk of developing postoperative FHI. The clinical outcomes for patients with FHI are poor, with no significant improvement in patient-reported outcomes observed.