Follow-up Research Of Primary Total Hip Arthroplasty With An Uncemented Proximal Modular Femoral Stem

Objective To evaluate the clinical and radiographical results of primary total hiparthroplasties(THA) using uncemented proximal modular femoral stems（Sivash-Range ofMotion）with short term follow-up.Methods36patients(38hips) accepted primary THA using S-ROM stem fromJanurary2009to September2009.2patients(2hips) were lost in the follow-up,theremaining34patients(36hips) finished the final follow-up and formed the basis of thisstudy.In this cohort,there were17male patients and17female patients with mean age of50.9±11.8(range,20~75years).The diagnosis before the surgery were femoral head necrosisin18hips,osteoarthrisis in7hips,developmental dysplasia of hip in9hips and ankylosingspondylitis in2hips.The head-liner combinations were ceramic-on-ceramic in8hips,metal-on-metal in25hips,ceramic-on-metal in2hips and ceramic-on-polyethylene in1hip.The clinical results of the hip in surgery were matched between the pre-andpost-operational.Meanwhile,the radiographic signs around the implant were observed andanalysed in each follow-up.Results There was no incidence of infection,dislocation and nerve or vascularinjuries in our group.Minor fracture of femoral calcar occurred during the process offemoral stem insertion.The average lower limb discrepancy was corrected into0.5cmbetter than2cm before the surgery.Slight thigh pain occurred in4patients after operation,while3of which responded the disappearence of the pain in1-year follow-upand the remaining one felt the relief of pain after taking anti-osteoporosis medicine.Afteran average follow-up of38months(36-44months),the mean Harris score increased frompreoperational (47.8±13.6) points to postoperational （91.4±4.2）points.Radiologically,27hips(75%) obtained bone ingrowth fixation in27hips(75%) while9hips(25%) showedevidence of fibrous stable fixation.Some degree of disuse atrophy in femur metaphysisappeared in all hips.Implant subsidence and periprosthetic osteolysis were not found.Norevisions were executed until the final follow-up for aseptic loosening or other reasons.Conclusion Noncemented proximal modular stem can provide optimal initialstability and long term fixation in primary THA.Short term follow-up results wereexcellent.