Aims. We compared the clinical outcomes of curved intertrochanteric varus osteotomy (CVO) with bone impaction grafting (BIG) with CVO alone for the treatment of osteonecrosis of the femoral head (ONFH). Methods. This retrospective comparative study included 81 patients with ONFH; 37 patients (40 hips) underwent CVO with BIG (BIG group) and 44 patients (47 hips) underwent CVO alone (CVO group). Patients in the BIG group were followed-up for a mean of 12.2 years (10.0 to 16.5). Patients in the CVO group were followed-up for a mean of 14.5 years (10.0 to 21.0). Assessment parameters included the Harris Hip Score (HHS), Oxford Hip Score (OHS), Japanese Orthopaedic Association Hip-Disease Evaluation Questionnaire (JHEQ), complication rates, and survival rates, with conversion to total hip arthroplasty (THA) and radiological failure as the endpoints. Results. There were no significant differences in preoperative and postoperative HHS or postoperative OHS and JHEQ between the BIG group and the CVO group. Complication rates were comparable between groups. Ten-year survival rates with conversion to THA and radiological failure as the endpoints were not significantly different between groups. Successful CVO (postoperative coverage ratio of more than one-third) exhibited better ten-year survival rates with radiological failure as the endpoint in the BIG group (91.4%) than in the CVO group (77.7%), but this difference was not significant (p = 0.079). Conclusion. Long-term outcomes of CVO with BIG were favourable when proper patient selection and accurate surgery are performed. However, this study did not show improvements in treatment results with the concomitant use of BIG. Cite this article: Bone Joint J 2021;103-B(4):665–671

Aims. This single-centre observational study aimed to describe the results of extensive bone impaction grafting of the whole acetabular cavity in combination with an uncemented component in acetabular revisions performed in a standardized manner since 1993. Methods. Between 1993 and 2013, 370 patients with a median age of 72 years (interquartile range (IQR) 63 to 79 years) underwent acetabular revision surgery. Of these, 229 were more than ten years following surgery and 137 were more than 15 years. All revisions were performed with extensive use of morcellized allograft firmly impacted into the entire acetabular cavity, followed by insertion of an uncemented component with supplementary screw fixation. All types of reoperation were captured using review of radiographs and medical charts, combined with data from the local surgical register and the Swedish Hip Arthroplasty Register. Results. Among patients with possible follow-up of ten and 15 years, 152 and 72 patients remained alive without revision of the acetabular component. The number of deaths was 61 and 50, respectively. Of those who died, six patients in each group had a reoperation performed before death. The number of patients with a reoperation was 22 for those with ten-year follow-up and 21 for those with 15 years of follow-up. The Kaplan-Meier implant survival rate for aseptic loosening among all 370 patients in the cohort was 96.3% (95% confidence interval (CI) 94.1 to 98.5) after ten years and 92.8% (95% CI 89.2 to 96.6) after 15 years. Conclusion. Extensive bone impaction grafting combined with uncemented revision components appears to be a reliable method with favourable long-term survival. This technique offers the advantage of bone stock restoration and disputes the long-standing perception that uncemented components require > 50% of host bone contact for successful implant survival. Cite this article: Bone Joint J 2020;102-B(2):198–204

Introduction. Total hip arthroplasties (THAs) in young patients are associated with high failure rates. We always use cemented total hip implants, however, in cases with acetabular bone stock loss we perform bone impaction grafting. Our purpose was to evaluate the outcome of 69 consecutive primary cemented total hips in patients younger than 30 years followed between 2 to 18 years. Methods. Between 1988 and 2004, 69 consecutive primary cemented THAs (mainly Exeters) were performed in 48 patients (32 women, 16 men) younger than thirty years. Average age at time of operation was 25 years (range, 16 to 29 years). Twenty-nine hips (42%) underwent acetabular bone impaction grafting because of acetabular bone loss. Mean follow-up was 10 years (range, 2 to 18 years). Revisions were determined, Harris Hip Score (HHS), and Oxford Hip Questionnaire Score (OHQS) were obtained and radiographs were analyzed. Survival was calculated using the Kaplan-Meier method. Results. No patients were lost to follow-up, but 3 patients (4 hips) died during follow-up, none of whom had underwent revision. Eight revisions were performed: 3 septic loosenings (6, 7, and 8 years post-operative) and 5 aseptic cup loosenings (2, 3, 4, 5, and 9 years post-operative). No stems were loose. The average HHS and OHQS at follow-up were 89 points (range, 55 to 100 points) and 19 points (range, 12 to 42 points), respectively. Using Kaplan-Meier analysis, the cumulative survival with revision for any reason as end point was 83% (95% CI, 69 - 92%) at 10 years. Excluding the infections, the survival rate was 90% (95% CI, 77 - 96%) with revision for aseptic loosening. The outcome of the patients who underwent acetabular bone impaction grafting was comparable to the primary cemented hips with a survival of 89% (95% CI, 62 - 97%) with revision for any reason as an end point. Excluding the infections, the survival rate was 95% (95% confidence interval, 72 - 99%) at ten years with revision for aseptic loosening as the end point. Conclusion. Primary cemented total hip arthroplasties in very young patients show satisfactory medium-term results, however, in cases with acetabular bone stock loss, a reconstruction with bone impaction grafting is advisable

Introduction. Especially in young patients, total hip implants with proven long-term follow-up data should be used. Despite this, almost all patients under 30 years old will face a revision of their hip prosthesis during their life time because of their life expectancy. Therefore, all the used implants should be revisable with reliable outcome. Although, several studies have evaluated the outcome of different THA implants in patients under 30, only few report the long term follow-up of 10 years or more. None of them present the outcome of the revised total hips. Methods. We retrospectively reviewed prospectively collected data of 48 consecutive patients (69 hips), all received a cemented implant and in case of acetabular bone stock deficiency (29 hips), a reconstruction with bone impaction grafting (BIG) was performed. Mean age at surgery was 24.6 years (range, 16.0–29.0 years). Two patients were lost to follow-up. As far as we know, no revisions are performed in these two patients and their data are included in the study up to their last radiographic control. All failed hips were revised with again cemented implants and, if needed, bone impaction grafting. For the primary THA Kaplan-Meier survival curves at 10- and 15-year endpoint revision for any reason and revision for aseptic loosening were calculated. Separate survival rates at 10- and 15- year were calculated for the BIG group versus the non-BIG group. The outcome of the revised hips was studied and reported with re-revision as the endpoint. Results. Mean follow-up of all 69 hips was 11.5 years (range 2–23.4 years). During follow-up 13 revisions were performed. No stem revisions occurred, except in 3 septic failures. The 10- and 15-year survival rates with endpoint revision for any reason were 86% (95%-CI: 74–92%) and 75% (95%-CI:59-86%), the same endpoints revision for aseptic loosening were 90% (95%-CI: 79–96%) and 82% (95%-CI: 65–92%), respectively. The 10- and 15-year survival rates with endpoint revision for any reason in the BIG group were 93% (95%-CI: 74–98%) and 83% (95%-CI:49-95%), whereas for the non-BIG group the rates were 81% (95%-CI: 69–91%) and 71% (95%-CI:50-84%). None of the 13 revisions needed a re-revision within 10 years after re-implantation, although one cup failed after 13 years. Conclusion. This study shows that cemented primary total hip implants in patients under 30 years have acceptable outcomes at 10 and 15 years after surgery. Remarkably, the outcomes of the bone impaction grafting technique are superior to non BIG hips, the BIG-group shows a higher survival percentage as the non-BIG group. However, the most interesting part of the study is that the revised hips, all again re-cemented and, if needed, reconstructed with bone impaction grafting were performing well with no re-revisions within 10 years after surgery

Introduction The results of THA in patients with post-traumatic arthritis are inferior to those in nontraumatic arthritis, both after cemented and noncemented THA. This increased failure rate is caused by the bone stock loss and the abnormal anatomy. We studied the outcome of acetabular bone impaction grafting and a cemented cup in 20 cases at 3 to 18 years follow-up. Materials and Methods Between January 1984 and January 2000 in 20 consecutive patients bone impaction grafting was used for arthritis after previous acetabular fracture, grafting was done in all for bone stock loss. There were 14 men and 6 women. The average age at THA was 53.3 years (range, 35 to 75 years). Defects were classified according to the AAOS acetabular defect classification (3 type I defects, 10 type II defects, 5 type III defects and 2 type V). Metal meshes were used in 6 medial wall and in 3 peripheral wall defects. In 15 cases autograft bone chips were used, in 5 both auto- and allograft was used. Grafts were impacted using impactors and a hammer and a PE cup was cemented. At review in January 2003 no patient was lost. Results Two patients died during follow up after 3 and 4 years respectively, deaths were not related to surgery and data are included. The mean follow up was 9.5 years (range, 3 to 18 years). The pre-operative Harris hip score was 44 (32–61). During follow up a cup revision was performed in two cases; one for a culture proven septic loosening 14.5 years after surgery and the other for aseptic loosening at 15.3 years after surgery. Both revised cups were radiologically loose at revision. At review the 16 surviving hips had an aver. Harris hip score of 93 points (range, 62 to 100 points). Fourteen hips were free of pain, one patient had slight and one had mild pain. Radiologically, none of these 16 cups was loose. However, two of the cups migrated more than 5 mm (e.g. 6 and 8 mm) relative to the initial post-operative X-ray. At review, both patients were symptom free. The Kaplan-Meier survival rate of the cup with endpoint revision for any reason was 100% at ten years and 80% (95% CI, 62–98%) after 15 years; with endpoint cup revision for aseptic loosening the survival was 100% both at 10 and 15 years. Conclusion The acetabular bone impaction grafting technique with a cemented cup is a biologically attractive technique to reconstruct the bone stock loss after posttraumatic arthritis with good long-term survival, even after long follow-up

Introduction. The different types of treatment for osteonecrosis of the femoral head have not led to a consensus about which treatment is best for the different stages. Particularly in the later stages of osteonecrosis, the disease still progresses to destruction of the femoral dome. The purpose of our study was to check the outcome of bone impaction grafting used for the head-preserving treatment of severe femoral head osteonecrosis. In order to preserve the femoral head, the sphericity and mechanical properties of the femoral dome must be contained and further collapse prevented. Methods. In this prospective study, we included 28 hips in 27 patients who had severe complaints of pain due to an extensive osteonecrotic lesion. The mean age of the patients was 33 years with a mean follow up time of 42 months. Results. Eight patients (29%) underwent a conversion to a total hip arthroplasty. The pre-operative Harris hip score for all cases was 55 points and the post-operative score was 79 points. Fifty-four percent of all cases showed a radiological and sixty-four percent a clinical success. The clinical success rate of Stage 2 was 73%, of early Stage 3, 67%, and late Stage 3, 45%. Conclusion. In conclusion, we can state that the bone impaction grafting technique shows promising results and is an excellent addition for the treatment arsenal for osteonecrosis of the femoral head

Bone impaction grafting (BIG) is a surgical technique for the restoration of bone stock loss with impaction of autograft or allograft bone particles (BoP). The goal of a series in-vitro and in-vivo experiments was to assess the suitability of deformable pure Ti (titanium) particles (TiP, FONDEL MEDICAL BV, Rotterdam, The Netherlands) for application as a full bone graft substitute in cemented revision total hip arthroplasty. TiP are highly porous (interconnective porosity before impaction 85 to 90%). In-vitro acetabular reconstructions were made in Sawbones (SAWBONES EUROPE, Malmö, Sweden) to evaluate migration by roentgen stereo photogrammetric analysis and shear force resistance by a lever out experiment. In-vitro femoral TiP reconstructions (SAWBONES, Malmö, Sweden) were used to evaluate micro-particle release and subsidence. Mature Dutch milk goats were used for two in-vivo experiments. A non-loaded femoral defect model was used to compare osteoconduction of bioceramic coated TiP with BoP and ceramic particles (CeP). Acetabular defects (AAOS type 3) were reconstructed in 10 goats using a metal mesh with impacted TiP acting as a full bone graft substitute in combination with a cemented polyethylene cup and a downsized cemented Exeter femoral stem (STRYKER BENOIST, Girard, France). Blood samples were taken for toxicological analysis. In-vitro: TiP were as deformable as BoP and created an entangled graft layer (porosity after impaction 70 to 75%). Acetabular TiP reconstructions were more stable and resistant to subsidence and shear force than BoP reconstructions (lever-out moment 56 ± 12 Nm respectively 12 ± 4 Nm, p < 0.001). After initial setting, femoral subsidence rates were smaller than seen in femoral bone impaction grafting (0.45 ± 0.04 mm after 300 000 loading cycles). Impaction generated 1.3 mg particles/g TiP (particle Ø 0.7–2 000 μm, tri-modal size distribution). In-vivo: Bioceramic coated (10 −40 μm) TiP showed bone ingrowth rates comparable to BoP and CeP. Reconstructed acetabular defects showed rapid bone ingrowth into the layer of TiP. Serum titanium concentrations slowly increased from 0.60 ± 0.28 parts per billion (ppb) preoperatively to 1.06 ± 0.70 ppb at fifteen weeks postoperatively (p = 0.04). Mechanical studies showed very good initial mechanical properties of TiP reconstructed defects. The in-vitro study showed micro-particle generation, but in the short-term goat studies, histology showed very few particles and no negative biological effects were found. The in-vivo acetabular study showed very favorable bone ingrowth characteristics into the TiP layer and a much thinner interface with the cement layer compared to similar defects reconstructed with BoP or mixtures of BoP with CeP. Further analysis in a human pilot study should proof that TiP is an attractive and safe alternative for allograft bone in impaction grafting revision arthroplasty

Background. These days, total hip arthroplasties (THA) are more implanted in young patients. Due to the expected lifespan of a THA and the life expectancy of young patients, a future revision is inevitable. Indirectly increasing the number of revisions in these patients. Therefore we evaluated the results of revision THA in patients under the age of 60 years. However, we used a unique protocol in which we used in all cases of acetabular and/or femoral bone deficiencies reconstruction with bone impaction grafting. Methods. To determine the mid- to longterm results of cemented revision total hip arthroplasties in patients under the age of 60, all clinical data and radiographs were analyzed of patients operated between 1992 and 2005. Patients with multiple previous revisions were also included. Only cemented components were used. During this period 146 consecutive revision total hip arthroplasties were implanted in 129 patients. This included 124 cup and 106 stem revisions. The average age at index surgery was 47 years. No case was lost. Mean follow-up was 7.6 (range, 2.0–16.7) years. Results. Outcome of clinical questionnaires improved significantly after revision THA. During follow-up 19% (28 hips) needed a repeat revision (aseptic loosening 13, septic loosening 10, recurrent dislocations 2, traumatic loosening 2, and abductor contracture 1). Seven of 146 cases (4.8%) ended finally in a permanent Girdlestone. Seventeen (14%) of the 124 cups were radiographically loose, 11 were revised. Four (4%) of the 106 stems were radiographically loose, 2 were revised. The 10-years survival was 78% with endpoint revision for any reason and 87% with endpoint revision for aseptic loosening. 28 hips needed repeat revision after the index revision. No significant differences in survival were found looking at the different indications for revision. Conclusions. The survival of cemented revision THA in patients under the age of 60 is satisfying. Reconstruction of acetabular and femoral bone deficiencies with bone impaction grafting is a promising and biological attractive technique in this young and high demanding population and enhances the revisability of a THA

Background. Because of the long life expectancy of young total hip arthroplasty (THA) patients and the limited durability of prosthetic implants in young patients, surgeon's always must take into account that the primary THA will be revised in the future. Therefore, not only the survival of the primary total hip in young patients is important, but we would also like to accentuate the revisability of a primary THA in this specific and high demanding patient population. Methods. Based on our philosophy, we always use cemented hip in young patients, if needed with acetabular bone impaction grafting. 343 consecutive cemented THA in 270 patients under the age of 50 years were evaluated, all implanted between 1988 and 2006. We also assessed the results of the revised THA (n=53) within the same population. Clinical, radiographical and survival of primary and revision THA were evaluated. Outcome. Survival analysis of all 343 hips with endpoint revision for any reason of either component showed a survival of 86% after 10 years. Survival of the stem and cup with endpoint aseptic loosening 93% after 10 years. Remarkably, the THA in which the cemented cup was combined with acetabular bone impaction grafting had a survival of 90% (SE 2.8) in contrast to a survival of 82% (SE 3.4) of the cups without an acetabular revision with endpoint revision for any reason of the whole prostheses(log-rank test, p=0.156) at 10 years. With no patient lost during follow-up, 53 primary hips were revised after a mean follow-up of 8.9 (range 2.0–19.3) years. The average follow-up of the revision THA was 4.2 (range 0.1–14.8) years. Three hips of this revision cohort needed a repeat revision, two had a reinfection after a septic revision and one revised cup failed 12 years after revision. The survival of the revised cohort with endpoint revision for any reason was 91% after 5 years, with endpoint aseptic loosening the survival at 5 years was 100 %. As well after primary as revision THA good clinical outcome scores were measured. Interpretation. Cemented implants in young patients showed satisfying results in primary as well as after revision THA with very acceptable survival and clinical outcomes. Keeping in mind that the young patient will outlive their primary THA, the primary hip has to be revisable and the results of the revision THA must be as good as the primary THA. Bone defects both in primary and revision THA can be successful managed with impacted bone grafts, without the need for augments, cages or larger implants

Introduction: Loosening of acetabular components often lead to excessive bone defects. Managing severe acetabular bone loss in revision arthroplasty is a serious or sometimes even an impossible challenge. Several authors even have published disappointing results. The purpose of this study was to evaluate the long term clinical and radiographic results of acetabular reconstruction with the use of bone impaction grafting and a cemented cup in cases with very large acetabular defects. Methods: In this historical prospective study, 27 hips (25 patients) with large acetabular defects (AAOS type III and IV, Paprosky type 2B to 3B) were reviewed. In all cases an extensive reconstruction with the use of bone impaction grafting and a large rim wire mesh (Stryker Howmedica, Newbury, UK) was performed. All patients have had a six week bed rest period or 3 weeks of bed rest with 3 weeks of non-weight bearing mobilization. No patient was lost to follow-up. Three patients died during follow-up, the cause of death was in all cases not related to the surgery. All medical files and radiographs were analyzed. Results: After a mean follow-up of 8.8 years (range 4 to 14.1), 3 hips needed repeat revision and another 2 hips were considered radiographic loose. Reasons for repeat revision were: septic loosening after 4.7 years, aseptic/traumatic loosening after 5.8 years and a broken-out reconstruction after 5 weeks because lack of compliance of the patient. Kaplan-Meier analysis showed a ten-year survival rate of 87% (95%C.I. 73.1–100%) with end point acetabular revision for any reason and 95% (95%C.I. 86.2–100%) with end point acetabular revision because of aseptic loosening. The mean preoperative HHS was 55 points and improved to 72 points postoperative. Conclusion: Acetabular reconstruction using impaction bone grafting and a cemented cup can produce favorable long-term results in patients with massive acetabular bone-stock defects. It is the only revision technique which restores massive acetabular bone stock loss. However, in these extensive defects it is a technical demanding procedure and should only be used by surgeons with extensive experience with this technique

Summary Statement. We analysed impaction bone grafting used together with cemented or uncemented fixation in acetabular revision surgery. The overall risk for re-revision did not differ between the cemented and uncemented group. However, aseptic loosening was more common in the cemented group. Background. Several surgical techniques address bone defects in cup revision surgery. Bone impaction grafting, introduced more than thirty years ago, is a biologically and mechanically appealing method. The primary aim of this study was to evaluate the effect of bone impaction grafting when used with uncemented and cemented fixation in cup revision surgery. Uncemented cups resting on more than 50% host bone were used as controls. Patient and Methods. Cup fixation was studied in ninety hips (eighty-two patients), revised due to loosening between 1993 and 1997. There were fifty-three isolated cup and thirty-seven total revisions. Patients were followed for thirteen years using conventional radiography, radiostereometry (RSA), Harris Hip score and a pain questionnaire. Peroperatively the surgeon assessed the acetabular bone bed vitality. In hips where the cup was judged to rest on > 50% vital bone (group I, n=43), an uncemented cup was used. If the cup was resting on ≤ 50% living bone, uncemented (group IIa, n=21,) or cemented (group IIb, n=26) technique was chosen, according to the surgeon's preference. The mean age of patients at index revision was 61±12 years, 56% were females. The most common index diagnosis was primary osteoarthritis (n=45) followed by rheumatoid arthritis (n=10). Results. At thirteen years, acetabular component failure had necessitated a second revision in 6/7/8 hips in Groups I/IIa/IIb respectively. These re-revisions were performed 1–10 (mean 7.1) years after index revision. Moreover four cup / liner revisions were performed in hips with femoral loosening, not allowing further RSA measurements. These twenty-five hips were followed until re-revision. Deceased patients (n=21) and patients with deteriorating medical condition, not able to attend the follow-up (n=7), were censored in the survival statistics. Aseptic loosening was the most common reason of re-revision. However, in the uncemented groups (I/IIa), four cups were re-revised due to liner wear, osteolysis or instability. In the total study population, and up to two years, the median proximal migration was lowest in Group I followed by Group IIa and Group IIb (p≤0,006). At thirteen years the mean proximal migration was highest in Group IIb 1.29 mm (SD 1.23) followed by Group I 0.30 mm (SD 0.40) and Group IIa 0.22 mm (SD 0.22), p = 0.05. In cases subsequently re-revised because of loosening or with radiographically loose cups at the last follow-up, a higher proximal migration was observed compared to the non-revised and radiographically well-fixed group (up to seven years: p < 0.001; thirteen years: p=0.04). Discussion/Conclusion. We found an increased risk for rerevision in cases with less than 50% host bone-implant contact. These cups showed high early proximal migration, measured by RSA, indicating poor initial fixation. Rate of re-revision due to any reason did not differ between cemented and uncemented cups. The cemented group (IIb) had a higher risk of being re-revised due to aseptic loosening. Poor bone stock, use of small bone chips, inferior impaction technique, and no or restricted contact with living bone are probable reasons for failures when extensive bone grafting is needed

Aims. The aim of this study was to compare the incidence of aseptic loosening after the use of a cemented acetabular component and a Trabecular Metal (TM) acetabular component (Zimmer Inc., Warsaw, Indiana) at acetabular revision with bone impaction grafting. Patients and Methods. A total of 42 patients were included in the study. Patients were randomised to receive an all- polyethylene cemented acetabular component (n = 19) or a TM component (n = 23). Radiostereometric analysis and conventional radiographic examinations were performed regularly up to two years post-operatively or until further revision. Results. The proximal migration was significantly higher in the cemented group. At two years, the median proximal migration was 1.45 mm and 0.25 mm in the cemented and TM groups, respectively (p = 0.02). One cemented component was revised due to dislocation. There were no revisions in the TM group. Conclusion. Lower proximal migration in the TM group suggests that this design might be associated with a lower risk of aseptic loosening in the long term compared with an all polyethylene cemented component. Longer follow-up is required to confirm the clinical advantages of using this component at acetabular revision. Cite this article: Bone Joint J 2017;99-B:880–6

Introduction: Tibial component loosening is a common mode of failure in modern total knee arthroplasty and is thus a common cause for revision knee surgery. Direct bone ingrowth of press fit knee prosthesis has been deemed an important prerequisite for long-lasting implant fixation and thus clinical success in both primary and revision TKA whether for cemented or uncemented stems. To achieve good long term biological stabilization, initial secure mechanical stability, (i.e. minimising tibial tray and stem motion with respect to the tibia,) is vital. A lack of initial stability can lead to resorption of bone at the implant-tissue interface and can consequently result in loosening and failure of the prosthesis. Obtaining adequate tibial fixation is difficult in revision patients as often there is insufficient bone stock in the proximal tibia. A longer stem is often recommended with revision surgery as a central stem should guide the migration of the tibial component so that it occurs predominantly along the vertical axis, thus minimising the risk of recurrent malalignment and loosening due to tilting of the tibial tray. It is also thought that the presence of a third rigid peg helps to reduce inducible displacements by anchoring the new implant in robust cancellous bone. However there is no consensus on the length of central stem should be to achieve the best load transfer and fixation and although the use of long stems on the tibial component is advocated, in revision TKA involving bone grafting and augmentation. The effect of the tibial stem length in other cases has received contradictory evaluations. This research deals with an experimentally evaluate the effect that central stem lengths on the initial micromotion of the tibial tray in two revision tibial defects. This is being investigated by measurement of the bone-implant interface motion of the tibial stem. Method: Composite bones were resected with an extramedullary jig. Three common revision defects were compared 1) no defect requiring no repair(primary); 2) T1 defect requiring bone impaction grafting; 3) T2A requiring augmentation. Three stem configurations were analysed in conjunction with these defects 1) no stem; 2) short 40mm stem; 3) long 80mm stem. Four LVDTs were positioned anteriorly, posteriorly, medially and laterally around the tray and were used to measure the movement of the tibial tray with respect to the tibia. The bones were potted and subjected to axial loading simulating 1– 6 times body weight for 3500 cycles at 1 Hz. Results: The longer stemmed press fit implants were associated with slightly higher levels of micromotion compared to the “no stem press fit” trays in the primary and T2A defects. This could be due to the fact that cutting errors are accentuated by a longer stem and can cause increased levels of posterior lift off. For bone impaction grafting it seems that a stem sufficiently long to by-pass the defect should be used. The proximal surface cemented trays presented more stable fixation with the inducible displacement between the no stem and stemmed groups being negligible. Subsidence of the tibial tray was reduced marginally by using a longer stem

Aims

The aim of this study was to assess the clinical and radiological results of patients who were revised using a custom-made triflange acetabular component (CTAC) for component loosening and pelvic discontinuity (PD) after previous total hip arthroplasty (THA).

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. Total hip arthroplasties in younger patients often requires revision because these patients frequently have acetabular deficiencies, which hamper proper implantation of the cup essential for good long-term prosthesis survival. For 30 years, we have used a biological acetabular-reconstruction technique with bone-impaction grafting in all patients <50 years with an acetabular deficiency at surgery, always in combination with a cemented total hip implant. Methods. We evaluated all 150 consecutive patients (177 hips) < 50 years with an acetabular reconstruction by bone-impaction grafting surgically-treated from 1978–2004 at our clinic. Mean follow-up was 10.3 (range, 2.0–28.3) years with no patient lost to follow-up. Mean index surgery age was 38.1 (range, 16–49) years. Clinical, radiological, and statistical analysis of all patients was performed. Results. Twenty-eight of 177 hips were revised at a mean of 10.5 years (range, 5 days to 23.2 years). Reasons for revision were: aseptic loosening (n=17), septic loosening (n=3), recurrent dislocations (n=3), traumatic loosening (n=2), neuropathy (n=1), wear (n=1), and fracture (n=1). Ten-year and 15-year survival with endpoint revision of any component for any reason was 91% and 78%. Ten-year survival with endpoint aseptic loosening was 96% for the cup and 97% for the stem. Conclusion. Performing a total hip implant in combination with acetabular bone impaction grafting in younger patients with acetabular bone stock loss seems to be an attractive approach as the long-term results are acceptable and fulfill the NICE-criteria, showing a ten -year survival of more than 90% with endpoint revisions for any reason

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

A cleaning process reduces the contamination risk in bone impaction grafting but also modifies the grain size distribution. The cleaned allograft shows a higher mechanical stability than the untreated group. In revision total hip replacement, bone loss can be managed by impacting porous bone chips. The bone chips have to be compacted to guarantee sufficient mechanical strength. To improve the safety of bone grafts and to reduce the risk of bacterial and viral contamination, cleaning processes are used to remove the organic portion of the tissue while maintaining its mechanical characteristics. A cleaning procedure described by Coraca-Huber et al. was compared to untreated allografts by performing a sieve analysis, followed by an uniaxial compression test. Differences in grain size distribution and weight loss during the cleaning procedure were compared to data from literature. Yield stress limits, flowability coefficients as well as initial density and density at the yield limit of the two groups were determined for each group over 30 measurements. The measurements were taken before and after compression with an impaction apparatus (dropped weight). The cleaning process reduced the initial weight by 56%, which is comparable to the results of McKenna et. al. Cleaned allograft showed a 25% lower weight of bone chips sized > 4 mm compared to data from a previous study. The cleaned bone chips showed a statistically significant (p > 0.01) higher yield limit to a compression force (0.165 ± 0.069 MPa) compared to untreated allograft after compaction (0.117 ± 0.062 MPa). The flowability coefficient was 0.024 for the cleaned allograft and 0.034 for the untreated allograft. Initial density as well as the density at the yield limit was higher for the untreated allografts, as the sample weight was twice as high as in the cleaned group, to compensate for the washout of the organic portion. The cleaned bone grafts showed a higher compaction rate, which was 31%, compared the the untreated group with a compaction rate of 22%. The cleaned allograft showed a higher compaction rate, which means that the gaps between the single grains are filled out with smaller particles, resulting in better interlocking. In the untreated allograft the interlocking mechanism is hindered by the organic elements. This observation is confirmed by a reduced flowabillity and a higher yield stress limit. The loss of weight as well as a higher compaction rate implies that more cleaned graft material is needed to fill bone defects in hip surgery. Sonication may damage the bone structure of the allograft and reduce the size of the particles

Introduction: Even in extensive osteonecrosis of the femoral head, a head-preserving method is preferable in younger patients. This study presents the results of bone impaction grafting for osteonecrosis of the femoral head. Materials and Methods: After a core biopsy and removal of the osteonecrotic area, impacted morsellized bone allografts were used to fill the femoral head to regain sphericity, and to prevent collapse. This prospective, single-surgeon study included 28 consecutive hips in 27 patients with extensive osteonecrotic lesions (ARCO classification Stage 2 (11 hips), Stage 3 (14 hips), and Stage 4 (three hips). Fourteen hips had preoperative collapse. The mean age of the patients was 33 years (range, 15–55 years). Results: At a mean follow-up of 42 months (range, 24–119 months), eight hips (29%) had been converted to a total hip arthroplasty. Of the 20 reconstructions that were in situ, 18 were clinically successful (90%) and 70% were radiologically successful. Patients who were younger than 30 years at surgery had a significantly better radiologic outcome, even when compared to heads with higher stages of osteonecrosis. Patients with preoperative collapse or a continuous use of corticosteroids had disappointing results. Discussion: This method is attractive as a salvage procedure for osteonecrosis of the femoral head. It is relatively simple and quick to perform, and it does not intervene with an eventual future hip arthroplasty

Aims: The effects of bone graft washing and bone graft particle size on initial cup stability in an acetabular model were studied. Methods: From fresh human femoral heads large (8–12 mm) and small (2–4) grafts were produced. Four different groups were tested; large washed, large unwashed, small washed and small unwashed. An AAOS type 3 combined defect was reconstructed in a synthetic acetabular model using a metal mesh and screws. Bone grafts were impacted in a standardized way using a hammer and metal impactors. Cement was pressurized and a PE cup was inserted. Cups were dynamically loaded with 1500 N and 3000 N for 15 minutes using an MTS-device, RSA was used to calculate 3-D cup migrations. Next a lever-out test of the cup was done in a displacement (16¡/minute) controlled test. After testing CT scans of the cups were made to quantify cement layer roughness, as a measurement of cement penetration. Results: Cups reconstructed with large washed bone grafts migrated signiþcantly less during mechanical compression and withstood signiþcantly higher lever-out moments. Washing improved cup stability for both small and large grafts, however only signiþcantly for the larger bone grafts. A signiþcantly higher cement penetration depth was found for all large bone grafts, washing did not inßuence cement penetration depth. Discussion: For acetabular revisions with bone impaction grafting we recommend to use large washed bone grafts