The capsular closure debate: Is hip stability phenotype the missing variable?

Despite 14 systematic reviews and meta-analyses published between 2018 and 2026, the role of capsular closure after hip arthroscopy for femoroacetabular impingement syndrome remains controversial. While several studies report superior outcomes following capsular repair, others demonstrate little or no clinically meaningful benefit. This persistent inconsistency raises the possibility that current meta-analyses may be addressing the wrong question. Most published studies compare different capsular management strategies, including non-closure, partial (T-capsule) repair and complete capsular closure, across highly heterogeneous patient populations while largely ignoring baseline hip stability characteristics. Patients with BDDH, generalized ligamentous laxity, increased femoral version, and other manifestations of microinstability are frequently analysed together with mechanically stable hips. Consequently, pooled estimates may represent averages across fundamentally different biomechanical phenotypes. The common hidden thread running through all the studies might simply be that capsular closure is likely dependent on the underlying stability profile of the hip rather than being universally beneficial or universally unnecessary. Future studies and meta-analyses should move beyond simple comparisons of closure versus non-closure and instead focus on stability phenotype-based analyses. The key question may no longer be whether capsular closure works, but rather in which hips capsular closure matters.