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Editorial - American Journal of Preventive Medicine and Public Health (2021)
Predisposes arthroplasty challenge in abnormal spinopelvic motion
Srinivas M*Srinivas M, Department of Orthopedics, Harvard Medical School Clinical Research Training, Egypt, Email: Srinivasmutthi@gmail.com
Published: 28-May-2021
Abstract
Total hip arthroplasty (THA) late dislocation is a main challenge. It is still an area of a research gap. Defining the late dislocation period is also a point of controversy, Charnely et.al define the period as more than five years, other authors define it as 1 to 2 years after primary THA
For simplicity, three different pattern of spinopelvic unbalance are descried. (1) fixed posterior pelvic tilt during standing with diminished spinopelvic motion which seen in lumbar spine degenerative diseases, it requires femoral hyperextension to stand, so it predisposes to a posterior impingement and a THA anterior dislocation. (2) fixed anterior pelvic tilt during setting with spinopelvic stiffness, which seen after lumbar spine fusion, this require femoral flexion in setting, so it predisposes to anterior impingement and a posterior hip dislocation. The third pattern has a decreased spinopelvic motion <100 between standing and sitting. Spinopelvic imbalance alters the functional position of the acetabulum which determined by the spinopelvic coordinated movement, adding a major risk factor for dislocation.
From a cohort of 9784 patients undergone a total hip arthroplasty following the established guidelines for a safe total hip procedure, 206 patients dislocated with 58% were correctly following the Lewinnek safe zone criteria for positioning the acetabulum component. Esposito et al in another 7040 patients cohort having total hip arthroplsaty, 147 hips dislocation reported, representing a 2.1% .After analyzing the matched data between dislocators and non dislocators, no difference was founded between the acetabulum components positions between the two groups. They concluded that we have to reconsider our concept of the factors affecting hip stability. phan D et al categorize the spinopelvic motion regarding lumbar spine pathology into four types; flexible and balanced, rigid and balanced, flexible and unbalanced, rigid and unbalanced. The last three abnormal motions leading to different types of hip impingement and consequent hip dislocation. The same study suggested different acetabular cup position for each type to improve the THA stability and reduce the dislocation rate. The Recent research focusing on total hip arthroplasty dislocation risk factors concluded that we should reconsider our established parameters for what we think is a safe total hip procedure.