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BACKGROUND: Bone defects are widely seen in patients with development dysplasia of hip or revision, thus resulting in a difficulty in acetabular treatment. High placement technique has been suggested to ensure the appropriate bone-prosthesis contact and simplify the surgery. Because biomechanics is involved, it has aroused many concerns,even its curative efficacy.OBJECTIVE: To summarize the research and progress of high placement technique applied in total hip arthroplasty (THA).METHODS: A computer-based online research was conducted for articles published until December 2016 in PubMed and CNKI databases using the keywords of proximal placement, superior placement, high placement, high hip center,elevated hip center, total hip arthroplasty, revision total hip arthroplasty, dysplasia of developmental hip in English and Chinese, respectively. Totally 67 literatures were retrieved, and finally 45 eligible articles were enrolled in accordance with the inclusion criteria.RESULTS AND CONCLUSION: (1) High placement technique is feasible for acetabular bone defects in THA, especially can simplify THA with complicated conditions. (2) Seemingly it goes against the principle of restoring anatomic hip center,but THA with high placement can obtain initial stability based on enough bone contact through adjusting the reconstruction position properly, interface improvement, appropriate prosthesis, as well as developed operations and conception, meanwhile, exposes no effect on biomechanics of hip. (3) Notably, the definition and term of high placement are chaotic in Chinese and English literatures, which need to be standardized further.
RESUMO
Objective@#To investigate the methods and short-time clinical results of reconstruction of Paprosky type Ⅲ acetabulum bone defects by using tantalum augments.@*Methods@#A total of 17 patients (17 hips) with Paprosky type Ⅲ acetabulum bone defects, treated with tantalum augments in revision of total hip arthroplasty at Department of Orthopedics Surgery in General Hospital of Chinese People′s Liberation Army were retrospectively analyzed from March 2014 to May 2016.There were 6 males and 11 females aged from 23 to 74 years with an average of (50.2±16.3) years. Tantalum augments or TM-Cup augment (the cup-on-cup technique) were used to reconstruct the defects.The TM-Cup augment was the tantalum revision cup which was removed titanium ring. The cup-on-cup technique combined TM-Cup augment and biological acetabulum cup. Augments were served as the nonresorptive structural allograft in revision of total hip arthroplasty. Harris hip score was used to evaluate clinical effects. The vertical position of the rotation center was measured and analyzed. Radiographic assessments of the acetabular components were performed by DeLee-Charnley and the Anderson criteria and recorded postoperative complications.@*Results@#All the patients were followed up from 3 to 29 months with an average of (16.2±5.4) months, tantalum augments and biological acetabulum cup were used in 13 patients, the TM-Cup augment and biological acetabulum cup were used in 4 patients. At the time of the latest follow-up, the mean Harris hip score increased compared to preoperatively (86.8±8.3 vs. 30.0±12.0) (t=12.78, P<0.01), the average vertical location of the center of rotation was decreased ((25.3±9.8) mm vs.(47.6±10.5)) mm (t=4.95, P<0.01). All the tantalum augments and biological acetabulum cups were stable, there were no infection, dislocation and other complications.@*Conclusions@#The use of tantalum augments could be considered as an effective management of Paprosky type Ⅲ defects providing good clinical and radiographic outcomes in the short term.The cup-on-cup technique which was used in reconstruction of severe superior-invagination acetabular bone defects and restoration relatively normal center of rotation had special application value.