The effects of early surgical interventions on hip joint loading

Cam femoroacetabular impingement (FAI) is a common cause of hip injuries, instability, and early joint degeneration. Early surgical intervention attempts to improve hip function, by restoring mobility and alleviating symptoms, but it is unclear how the morphology and capsule influence joint mechanics. This research program examined the contributions of hip preservation surgical stages towards: 1) functional mobility, 2) joint mechanics, and 3) microinstability. Surgical cam resection reduced hip torsional loading by 25% during flexion and internal rotation, but also increased microinstability by 31% during flexion and external rotation. As capsular repair can help restore some mobility in inherently unstable hips, caution must be taken to avoid large amplitudes of hip flexion and external rotation immediately after surgery.