Resistance to Axial Traction Decreases Over Time Following Repaired Periportal Capsulotomies During Hip Arthroscopy.

PURPOSE: To determine if distraction distance changes on an axial traction examination between the time zero capsular repair state and a later follow-up traction examination in patients with staged bilateral hip arthroscopies for femoroacetabular impingement syndrome.

METHODS

Patients between September 2022 and February 2025 who underwent staged, primary bilateral hip arthroscopies for femoroacetabular impingement syndrome with a closed periportal capsulotomy were included. Patients were excluded if they had prior hip surgery or had acetabular pathology beyond a labral tear. Fluoroscopic images were obtained at 0 and 100 pounds of axial traction force (lbf) at multiple time points: preinstrumentation, postcapsulotomy, postcapsular repair, and at follow-up during contralateral hip surgery. Linear regression assessed the change in distraction distance over time between time zero repair and the follow-up distraction distance, whereas logistic regression evaluated factors associated with substantial distraction increase, defined by the minimal detectable change.

RESULTS

Forty-one patients (41 hips, mean age 25.7 ± 11.4 years, 66% female) were included. Mean lateral center edge angle was 28.5 ± 5.0° and mean alpha angle was 59.7 ± 7.4°. Mean time between surgeries was 248 ± 191 days [range 43-833]. Compared with the native state, a repaired periportal showed greater resistance to axial traction at 100 lbf (8.50 ± 2.35 mm vs 6.37 ± 2.67 mm; P = .01). Regression analysis showed a significant relationship between time since surgery and increase in distractibility (β = 0.003, 95% confidence interval [0.001-0.006], P = .01). Logistic regression identified female sex (β = 1.74, 95% confidence interval [1.02-31.9], P = .04) as a predictor of a substantial postoperative increases in distractibility (minimal detectable change ≥1.2 mm).

CONCLUSIONS

A repaired periportal capsulotomy shows increased resistance to axial traction compared with the native state at time zero; however, this resistance progressively decreases over time and returns to the native state on follow-up testing.

LEVEL OF EVIDENCE: Level IV, retrospective case series.