Introduction

Revision Total Hip Arthroplasties (THA) have a significantly higher failure rate than primary THA's and the most common cause is aseptic loosening of the cup. To reduce this incidence of loosening various porous metal implants with a rough surface and a porous architecture have been developed which are said to increase early osteointegration. However, for successful osteointegration a minimal micromotion between the implant and the host bone (primary stability) is beneficial. It has not been previously determined if the primary stability for the new Gription® titanium cup differs from that of the old Porocoat® titanium cup.

Managing severe acetabular bone defects during primary and revision total hip arthroplasty is a challenging problem. Standard treatment options for this cases is using of acetabular reconstruction type-Burch-Schneider rings. Unfortunately, the possibility of osseointegration of these implants with surrounding bone has always remained a contentious issue. The emergence in recent years of new designs of trabecular titanium, representing a symbiosis of acetabular reconstructive plates and modular cup helped to solve this problem on a completely new level. The aim of this prospective study is to evaluate the short and mid-term clinical and radiographic outcomes of different types of acetabular revision cups - old and new design. From 2006 to 2015, we performed 48 acetabular reconstruction with reconstruction rings CONTUR Smith and Nephew(group 1) and 34 operations with Delta TT Lima Revision system (group 2). The mean age of patients was 59.2 years (range 30–79). Indications for operations included fractures in acetabular region (10 pat – 12,2 %), acetabular nonunions with bone defects (14 pat – 17,1%), aseptic loosening with multiple dislocation of the primary implants in 38 cases (46,3%) and second stage of infection treatment in 20 cases (24.4%). Clinical and functional outcomes were evaluated by Harris Hip Score (HHS). Bone density in Charnley's zones was measured by dual-energy x-ray absorptiometry. With CONTUR reconstruction rings were used 3 different types of bearing surface articulation (22 metal/polyethylene, 10 ceramic/polyethylene, and 16 oxinium/polyethylenel). With Delta TT Revision system were used metal/poly couples in 22 cases, ceramic/poly in 6 cases, and ceramic/ceramic couple in 4 cases. In two patients with high risk of dislocations were used double mobility system. In all operations with CONTUR rings was used bone impaction grafting to fill cavitary defects (Paprosky 2B-3A), with Delta TT Revision system in 14 cases (41,2%) additionally TT augments were used. In group 1 were 3 dislocations (6,3 %), 2 deep infections (4,2 %) and 4 aceptic loosenings with secondary instability of implants (8,3 %). In group 2 Trabecular Titanium showed a high capacity of osseointegration, providing good results in short-term follow-up. We registered only 2 dislocations (5,8 %) and 1 aceptic loosening (2,9 %). The mean HHS increased from 39.7 (range 23–62) preoperatively to 86.5 (range 68–98) at the last follow-up examination. The implanted cups were radiographically stable at the last follow-up visit (1 and 2 years) without radiolucent lines or periprosthetic osteolysis. Conclusions. Delta Revision TT is a good solution for acetabular reconstruction even when there are cavitary and segmental bone defects. Modularity of this system make it possible to correct inlay position, center of hip rotation and minimising the risk of dislocation

INTRODUCTION. Trabecular Titanium is an open-cell regular structure composed by hexagonal cells of controlled pore, manufactured by Electron Beam Melting (EBM) technology, that allows moulding of cellular solid structures. The Lima Delta TT revision cups are One and Revision, which is characterized by a caudal hook and fins. Both allow internal modularity and cranial TT augments. The aim of this prospective study is to evaluate the short to medium-term clinical and radiographic outcomes of acetabular revision cups in TT. METHODS. Between December 2008 and March 2013 we performed 60 cup revisions, 33 with the Revision cup and 27 with the One cup. The bone defect was classified according to Paprosky acetabular classification: type IIb and IIc presenting continent anterior and posterior acetabular wall were treated by Delta One TT; type IIIa and IIIb were treated with Delta TT Revision. In 20 cases (3.3%) stem revision was associated. Causes of revision were: aseptic loosening in 48 cases, periprosthetic acetabular fractures in 5 cases, recurrent dislocation in 5 cases, infection in 2 cases. In 52 cases bone grafts were used to fill cavitary defects (AIR 1–4). Hemispheric TT augments were used in 13 cases with the same aim. Internal modules were used in 39 cases to restore correct offset. The mean age of patients was 69.6 years (range 29–90). The average follow-up was 39 months (range 19–70). RESULTS. Mean Harris Hip Score (HHS) was 39.9 preoperatively and 82.7 at last follow-up. We had no intraoperative complications. We had 2 cases of superficial infection, one of which required revision of the surgical wound. 4 patients suffered dislocation episodes (1 recurrent); none of them required revision. We had 1 case of asymptomatic aseptic loosening, which did not require intervention. In the remaining cases no radiographic evidence of radiolucent lines was noticed at follow up, neither any evidence of aseptic loosening. The graft was considered to be integrated in all cases. DISCUSSION AND CONCLUSION. Trabecular Titanium revision cups showed high capacity of osseointegration, providing good results in short to medium-term follow-up. Further studies are necessary to assess long-term survivorship

INTRODUCTION. Managing severe periacetabular bone loss during revision total hip arthroplasty (THA) is a challenging task. Multiple treatment options have been described. Delta Revision Trabecular Titanium™ (TT) cup is manufactured by Electron Beam Melting (EBM) technology that allows modulating cellular solid structures with an highly porous structure were conceived to rich the goals of high bone ingrowth and physiological load transfer. The caudal hook and fins ensure additional stability and the modular system allows the surgeon to treat bone defects in the most complex revisions. Entirely modular, the system can meet all intra-operative needs thanks to a customized implant construction. The aim of this prospective study is to evaluate the short to mid-term clinical and radiographic outcomes of this acetabular revision cups. MATERIALS AND METHODS. We prospectively assessed clinical and radiographic results of 31 cases of acetabular revisions that were performed from June 2007 and March 2012 by Delta TT Lima Revision system. The mean age of patients was 69.5 years (range 29–90). The causes of revision were aseptic loosening in 22 cases (71.0%), periprosthetic acetabular fractures in 4 cases (13.0%), multiple dislocation of the primary implant in 3 cases (9.6%) and outcome of infection in 2 cases (6.4%). Stem revision was performed in 11 cases (35,4%). In 24 cases bone impaction grafting was used to fill cavitary defects (Paprosky 2B-3A); in 7 cases TT augments were used with the same aim. The average follow-up was 32 months (range 12–69). RESULTS AND CONCLUSIONS. No major complications were observed. The mean HHS significantly increased from 39.9 (range 17–60) preoperatively to 86.5 (range 65–100) at the last follow-up examination. The implanted cups were radiographically stable at the last follow-up visit without radiolucent lines or periprosthetic osteolysis. Trabecular Titanium showed a high capacity of osseointegration, providing excellent results in short to mid-term follow-up. The impaction grafting has demonstrated effective restoration of bone stock and no radiographic evidence bone resorption (Fig. 1). DISCUSSION. Delta Revision TT is a good solution for acetabular revision surgery even when there are cavitary and segmental bone defects. It is possible to restore muscle tension and correct anatomical impairments, while enhancing implant stability and minimising the risk of dislocation

Introduction:. Acetabular revision Jumbo cups are used in revision hip surgeries to allow for large bone to implant contact and stability. However, jumbo cups may also result in hip center elevation and instability. They may also protrude through anterior wall leading to ilopsoas tendinitis. Methods:. The study was conducted using two methods:. Computer simulation study. 265 pelvic CT scans consisting of 158 males and 107 females were converted to virtual 3-dimensional bones. The average native acetabular diameter was 52.0 mm, SD = 4.0 mm (males in 52.4 mm, SD = 2.8 mm and 46.4 mm, SD = 2.6 mm in females). Images were analyzed by custom CT analytical software (SOMA™ V.3.2). 1. and over-sized reaming was simulated. Four distinct points, located in and around the acetabular margins, were used to determine the reamer sphere. Points 1, 2, 3 were located at the inferior and inferior-medial acetabular margins, and Point 4 was located superiorly and posteriorly in the acetabulum to simulate a bony defect in this location, Point 4 was placed at 10%, 20%, 30%, 40%, 50% and 60% of the distance from the superior – posterior margin of the acetabular rim to the sciatic notch to simulate bony defects of increasing size. (Figure 1). Radiographical study. Retrospective chart review of patient records for all cementless acetabular revisions utilizing jumbo cups between January 1, 1998 and March 30, 2012 at UCFS (98 patients with 57 men, 41 women). Jumbo cups: ≥66 mm in males; <62 mm in females. Reaming was directed inferiorly to the level of the obturator foramen to place the inferior edge of the jumbo cup at the inferior acetabulum. To determine the vertical position of the hip center, a circle was first made around both the jumbo and the contralateral acetabular surfaces using Phillips iSite PACS software. The center of this circle was assumed to correspond to the “hip center”. The height of the hip center was estimated by measuring the height of a perpendicular line arising from the interteardrop line (TL) and ending at the hip center. Results:. The computer simulation and radiographic analysis deomonstrated similar results. The computer simulation predicted that the hip center shifted superiorly and anteriorly as the reamer size increased. The hip center shifted 0.27 mm superiorly and 0.02 mm anteriorly for every millimeter in diameter increased for the reaming. (Figure 2) Anterior column bone removal was increased 0.86 mm for every 1 mm of reamer size increase. (Figure 3). Results of radiographical study is shown in Table bellow:. Discussion:. Use of a jumbo cup in revision THA results in elevation of the hip center. Therefore a longer femoral head may be needed to compensate for hip center elevation when a jumbo cup is used. Reaming for a jumbo cup can also result in loss of anterior bone stock and protrusion of the cup anteriorly which may cause iliopsoas tendonitis

We report the use of porous metal acetabular revision shells in the treatment of contained bone loss. The outcomes of 53 patients with ≤ 50% acetabular bleeding host bone contact were compared with a control group of 49 patients with > 50% to 85% bleeding host bone contact. All patients were treated with the same type of trabecular metal acetabular revision shell. The mean age at revision was 62.4 years (42 to 80) and the mean follow-up of both groups was 72.4 months (60 to 102). Clinical, radiological and functional outcomes were assessed. There were four (7.5%) mechanical failures in the ≤ 50% host bone contact group and no failures in the > 50% host bone contact group (p = 0.068). Out of both groups combined there were four infections (3.9%) and five recurrent dislocations (4.9%) with a stable acetabular component construct that were revised to a constrained liner. Given the complexity of the reconstructive challenge, porous metal revision acetabular shells show acceptable failure rates at five to ten years’ follow-up in the setting of significant contained bone defects. This favourable outcome might be due to the improved initial stability achieved by a high coefficient of friction between the acetabular implant and the host bone, and the high porosity, which affords good bone ingrowth.

In acetabular revision press-fit cups usually are used in smaller defects and contact to the host bone should be more than 50 %. Due to the thin wall thickness and the surface design the cementless press-fit cup Allofit S has a specific characteristic during implantation. Therefore this cup was used for revision with greater acetabular defects and analysed in a prospective study. The press-fit in these cases was 4 mm and additional 2 or 3 screws into the Os ilium were used. 64 cups were were followed prospectively for 38.3 months with a minimum of 24 months and examined clinically (Harris-Hip-Score) and radiographically for migration (Method of Nunn et al.) and loosening (Method of Delee and Charnley). Corresponding to Nunn et al. and Blum et al., cup migration was defined to be a change of position greater than 3 mm or referring to Cordero-Ampuero et al. and Dickob et al. a change of inclination greater than 5 degrees. There were 25 revisions of the cup and 39 complete exchanges of the prosthesis due to 54 aseptic and 10 septic loosenings (two-step revision with spacer and cementless reimplantation). There were acetabular defects of type Paprosky 2A in 12 cases, of type 2B in 15 cases, type 2C in 19 cases, type 3A in 16 cases and type 3 B in 2 cases. The average age of the patients was 70.9 ± 8.9 years. The Harris-Hip-Score increased from 45.4 ± 14.9 points preoperatively to 81.8 ± 17.5 points one year and 82.3 ± 17.1 points two years postoperative. There was no loosing or significant migration of the cups. The Allofit S press-fit cup shows good result in cup revisions with greater acetabular defects when using a press-fit of 4 mm and additional 2 or 3 screws. In these cases it seems to be a good and cheeper alternative to specific implants like trabecular metal cups