Age and Preoperative Anterior Hip Capsule Thickness May Affect Capsule Healing in Patients With Femoroacetabular Impingement Syndrome Undergoing Arthroscopic Surgery Without Capsule Repair

The capacity of an unrepaired joint capsule to heal after primary hip arthroscopic surgery in patients with femoroacetabular impingement syndrome (FAIS) remains uncertain. The factors that may contribute to nonhealing of the joint capsule are yet to be elucidated.

To report the healing rate of the unrepaired joint capsule after primary hip arthroscopic surgery and to identify factors that may contribute to nonhealing.

Case-control study; Level of evidence, 3.

Data collected between August 2015 and October 2023 were reviewed. Patients with FAIS aged 18 to 65 years who underwent hip arthroscopic surgery without capsule repair and had a minimum 6-month follow-up were included. Patient demographic data were collected including age at the time of surgery, sex, body mass index, laterality of the affected hip, follow-up duration, FAIS type, and intraoperative procedures. Capsule thickness was measured on preoperative magnetic resonance imaging. The status of capsule healing was evaluated on magnetic resonance imaging at least 6 months after surgery. The correlation between an unhealed capsule and various clinical factors was also evaluated.

A total of 64 patients (66 hips) were included for analysis (48 hips in the healed group and 18 hips in the unhealed group). Age (44.50 ± 11.36 vs 38.44 ± 10.52 years, respectively; P = .045) and preoperative anterior capsule thickness (3.02 ± 0.87 vs 3.64 ± 1.01 mm, respectively; P = .025) were significantly different between the unhealed and healed groups. Other patient characteristics did not significantly differ between the groups. Higher age (ρ = -0.247; P = .045) and thinner anterior capsule (ρ = 0.276; P = .025) were associated with unhealed capsules. Receiver operating characteristic curve analysis showed that the optimal cut-off value for anterior capsule thickness to discriminate between healed and unhealed capsules was 3.35 mm, with a sensitivity and specificity of 0.667 and 0.667, respectively. The optimal cut-off value for age was 43 years, with a sensitivity and specificity of 0.667 and 0.604, respectively.

At a minimum 6-month follow-up, 27.2% of patients with FAIS who underwent primary arthroscopic surgery had unhealed anterior hip capsules. Both higher age and lower preoperative anterior hip capsule thickness may affect capsule healing in patients with FAIS who undergo primary arthroscopic surgery without capsule repair.