Factors Affecting The Stability After Total Hip Arthroplasty And Analysis Of Typical Clinical Cases

Since the technology of total hip arthroplasty developed, it has became the mosteffective method to treat the severe hip diseases, such as osteonecrosis of the femeralhead, osteoarthritis of hip, developmental dysplasia of the hip, ankylosing spondylitisand so on. The quantity of patients’ life can be obviously improved through THA.Even someone mentioned whether the athletes can go back to the field after THA, butthere was no clinical evidence to support this, it may increase the risk of fracture anddislocation, and have bad effect of long term fellow-up. THA also has manycomplications, an unstable hip for both patients and doctors is a disaster. Thedislocation rate of primary total hip arthroplasty can range from1.1%to12.1%, and itmay increase to39%for recurrent dislocation, however it has decreased to about2%due to the improvement of surgical techniques and prosthesis. The dislocation rate ishigher in revision, especially for those only revised acetabulum, and it also increasedwith the times of revision. Joint instability and aseptic loosening of the patients whoreceived revision in5years after primary THA accounted for70%in the study ofMelvin JS’s. Causes of instability are various, this article will make a summary of therelated factors in unstable hips after total hip arthroplasty through the search of CNKIand PubMed database, use the words such as “THA、THR、dislocation、head size、approach、soft tissue、rehabilitation、prosthesis、acetabular、capsule、femur neckfracture、DDH” to search articles, and analyzed with the typicalcases of ourdepartment. Conclusion: The factors related to unstable hip after THA are varied inmany aspects：1、patient’s own factors: patients with old age, low muscle strengthorfemur neck fracture are at high risk;2、prosthesis’s factors: metal on metal surfacemay produce more fabrics, ceramic on ceramic surface seems to be more durable, butit may cause ceramic’s fracture, acetabulum should be put into safe zone, and bigdiameters head could decrease dislocation;3、the skill of operation: the approach of surgery can influence dislocation, The posterolateral approach is more easy todislocate,but combined with soft tissue reconstruction and the use of big head coulddecrease the risk.4、rehabilitation; it should be exclusive to different patients, topractice early may be helpful, and avoid some actions like excessive flexion, internalrotation, adduction. The dislocation has been clearly decreased since the developmentof surgical skills and prosthesis. Most of dislocation can’t be attribute to one factor,they interact with each other. What we should do is to ensure every step to be correctas possible in order to guarantee the success of surgery.