The Preoperative Central Joint Space Holds Greater Clinical Significance in Patients Aged 35 and Older Undergoing Primary Hip Arthroscopy.

Background: Hip arthroscopy effectively treats femoroacetabular impingement (FAI) to preserve joint function and alleviate symptoms. Joint space widths (JSWs) and ratios may predict surgical outcomes, especially in older patients.

Purpose: To assess the relationship between the preoperative lateral-to-medial (L/M) ratio, the central-to-medial (C/M) ratio, and postoperative functional scores following arthroscopic treatment for FAI in patients aged ≥35 years.

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

Methods: Patients who had primary hip arthroscopy for FAI between February 5, 2013, and June 1, 2022, with a minimum 2-year follow-up, were included and categorized into 2 age groups (≥35 years and <35 years). Radiographic measurements of JSW on plain anteroposterior pelvic radiographs were used to calculate L/M and C/M ratios. Patient-reported outcomes included the modified Harris Hip Score (mHHS) and visual analog scale for pain. Statistical analysis included chi-square, Mann-Whitney U, and Wilcoxon tests to compare categorical and continuous variables. The receiver operating characteristic (ROC) curve and area under the curve (AUC) assessed threshold values for L/M and C/M ratios predicting the Patient Acceptable Symptom State (PASS) for mHHS at 2 years.

Results: A total of 110 patients (114 hips) were identified, comprising 56 hips from the older group (age ≥35 years) and 58 hips from the younger group (age <35 years). The ROC curve for preoperative C/M effectively distinguished between patients who achieved and did not achieve a second-year PASS value, with an AUC of 0.70 in older patients. Older patients, compared with younger, demonstrated lower postoperative mHHS (89 ± 10 vs 94 ± 8; P = .01) but similar rates of PASS achievement (75% vs 88%; P = .07). The C/M ratio was a significant predictor of functional outcomes in patients aged ≥35. Patients with a preoperative C/M ratio ≥1.08 achieved significantly better outcomes. No significant predictive value was found for L/M ratios in older patients or for L/M and C/M ratios in younger patients.

Conclusion: Our study demonstrated that the central JSW is a sensitive prognostic indicator in older patients undergoing primary hip arthroscopy. A preoperative C/M ratio ≥1.08 correlates with higher rates of achieving PASS. Identifying preoperative predictors, such as the C/M JSW ratio, assists surgeons in determining patients (≥35 years) who are more likely to benefit from hip arthroscopy.