The role of roentgen stereophotogrammetric analysis in assessing early migration of femoral implant after total hip arthroplasty with modular prostheses / 中华骨科杂志

ABSTRACT

Objective To investigate the value of roentgen stereophotogrammetric analysis (RSA) in assessing early migration of femoral implant after total hip arthroplasty (THA) with modular prostheses.Methods From May 2009 to April 2010,37 patients underwent THA with modular prostheses inour hospital,including 25 males and 12 females,aged from 58 to 72 years (average,60.23±5.64 years).There were 32 cases of degenerative osteoarthritis,3 cases of femoral neck fracture and 2 cases of developmental dysplasia of the hip.The Harris hip score and RSA were used to assess the clinical results and the migration of femoral implant at 3,6,12,24 months postoperatively,respectively.Results The average Harris hip score improved from preoperative 26.36 ±10.56 to 78.24±12.72,84.51±16.05,86.72±9.34,and 87.55±8.97 at 3,6,12,and 24 months after operation,respectively,and the differences between pre-and post-operative Harris score were significant.There was no prosthetic revision,and slight thigh pain occurred in 3 patients.According to RSA,the degree of initial migration of femoral implant had large individual differences,and the initial migration was higher from 3 to 6 months after operation.Clinical and biological stabilization was achieved in 36 patients,while progressive migration was found in 1 patient.There was a positive correlation between the distal migration and posterior migration within 24 months after operation (r=0.3,P=0.01).The distal migration and posterior migration/rotation mainly occurred within 3 months after operation.There was no correlation between prosthetic size/offset and degree of migration of implant.Conclusion RSA provides an objective reference for assessing the migration of femoral implant after THA with modular prostheses,which is a reliable method to evaluate early implant stability.