| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 4050428 | Clinical Biomechanics | 2014 | 7 Pages |
•Proper implant orientation is essential for avoiding edge-loading and prosthesis impingement in total hip arthroplasty.•We simulated appropriate implant orientation for avoiding those risks, even with a change in pelvic tilt after surgery.•We assumed that hip range of motion shifted in the extension direction along with posterior pelvic tilt long after surgery.•Edge-loading and impingement can be prevented by performing appropriate surgery in most realistic cases.•It may also be important to pay attention to spinal conditions to ensure that pelvic tilting is not extreme.
BackgroundProper implant orientation is essential for avoiding edge-loading and prosthesis impingement in total hip arthroplasty. Although cup orientation is affected by a change in pelvic tilt after surgery, it has been unclear whether surgeons can prevent impingement and edge-loading by proper positioning by taking into account any change in pelvic alignment associated with alteration of hip range of motion.MethodsWe simulated implant orientation without edge-loading and prosthesis impingement, even with a change in pelvic tilt and associated change in hip range of motion after surgery, by collision detection using implant models created with computer-aided design.FindingsIf posterior pelvic tilting with a corresponding hyperextension change in hip range of motion after surgery remains within 10°, as occurs in 90% of cases, surgeons can avoid edge-loading and impingement by correctly orienting the implant, even when using a conventional prosthesis. However, if a 20° change occurs after surgery, it may be difficult to avoid those risks.InterpretationAlthough edge-loading and impingement can be prevented by performing appropriate surgery in most cases, even when taking into account postoperative changes in pelvic tilt, it may also be important to pay attention to spinal conditions to ensure that pelvic tilting is not extreme because of increasing kyphosis.
