J Bone Joint Surg Am. 2019 Dec 4; 101(23): 2141–2151.

Hip Joint Capsular Anatomy, Mechanics, and Surgical Management

K.C. Geoffrey Ng, PhD,1 Jonathan R.T. Jeffers, PhD,2 and Paul E. Beaulé, MD, FRCSCcorresponding author3

Hip

Hip joint capsular ligaments (iliofemoral, ischiofemoral, and pubofemoral) play a predominant role in functional mobility and joint stability.
➤ The zona orbicularis resists joint distraction (during neutral positions), and its aperture mechanism stabilizes the hip from adverse edge-loading (during extreme hip flexion-extension).
➤ To preserve joint function and stability, it is important to minimize capsulotomy size and avoid disrupting the zona orbicularis, preserve the femoral head size and neck length, and only repair when or as necessary without altering capsular tensions.
➤ It is not fully understood what the role of capsular tightness is in patients who have cam femoroacetabular impingement and if partial capsular release could be beneficial and/or therapeutic.
➤ During arthroplasty surgery, a femoral head implant that is nearly equivalent to the native head size with an optimal neck-length offset can optimize capsular tension and decrease dislocation risk where an intact posterior hip capsule plays a critical role in maintaining hip stability.