Aims

Post-traumatic periprosthetic acetabular fractures are rare but serious. Few studies carried out on small cohorts have reported them in the literature. The aim of this work is to describe the specific characteristics of post-traumatic periprosthetic acetabular fractures, and the outcome of their surgical treatment in terms of function and complications.

Aims

The main aims were to identify risk factors predictive of a radiolucent line (RLL) around the acetabular component with an interface bioactive bone cement (IBBC) technique in the first year after THA, and evaluate whether these risk factors influence the development of RLLs at five and ten years after THA.

Aims. The purpose of this retrospective study was to evaluate the minimum five-year outcome of revision total hip arthroplasty (THA) using the Kerboull acetabular reinforcement device (KARD) in patients with Paprosky type III acetabular defects and destruction of the inferior margin of the acetabulum. Patients and Methods. We identified 36 patients (37 hips) who underwent revision THA under these circumstances using the KARD, fresh frozen allograft femoral heads, and reconstruction of the inferior margin of the acetabulum. The Merle d’Aubigné system was used for clinical assessment. Serial anteroposterior pelvic radiographs were used to assess migration of the acetabular component. Results. At a mean follow-up of 8.2 years (5 to 19.3), the mean Merle d’Aubigné score increased from 12.5 (5 to 18) preoperatively to 16.5 (10 to 18) (p < 0.0001). The survival rate at ten years was 95.3% (. sd. 4.5; 95% confidence interval (CI) 86.4 to 100) and 76.5% (. sd. 9.9, 95% CI 57.0 to 95.9) using aseptic loosening and radiological loosening as the endpoints, respectively. Conclusion. These results show that the use of the KARD with reconstruction of the inferior margin of the acetabulum in revision THA is associated with acceptable clinical results and survival at mid-term follow-up with, however, a high rate of migration of the acetabular component of 21.6%. Cite this article: Bone Joint J 2018;100-B:725–32

Introduction. Acetabular reconstruction of a total hip arthroplasty (THA) for a case with severe bone loss is most challenging for surgeon. Relatively high rate of failure after the reconstruction surgery have been reported. We have used Kerboull-type acetabular reinforcement devices with morsellised or bulk bone allografts for these cases. The purpose of this study was to examine the midterm results of revision THA using Kerboull-type acetabular reinforcement devices. Patients and methods. We retrospectively reviewed 20 hips of revision THA (20 patients) between February 2002 and August 2010. The mean age of the patients at the time of surgery was 67.4 years (range 45–78). All of the cases were female. The mean duration of follow-up was 6.5 years (range 2.1–10.4). The reasons of revision surgeries were aseptic loosening in 10 hips, migration of bipolar hemiarthroplasty in 8 hips, and rheumatoid arthritis in 2 hips. We classified acetabular bone defects according to the American Academy of Orthopaedic Surgeons (AAOS) classification; we found two cases of Type II and eighteen cases of Type III. In terms of bone graft, we performed both bulk and morsellised bone grafts in 6 hips and morsellised bone grafts only in 14 hips. We assessed cup alignment using postoperative computed tomography (CT) and The post-operative and final follow-up radiographs were compared to assess migration of the implant. We measured the following three parameters: the angle of inclination of the acetabular device (Fig. 1); the horizontal migration (Fig. 2a); and vertical migration (Fig. 2b). Substantial migration was defined as a change in the angle of inclination of more than 3 degrees or migration of more than 3 mm. The pre- and postoperative hip functions were evaluated using the Japanese Orthopaedic Association (JOA) hip score. Results. The mean cup inclination and anteversion were 38.4 degrees and 10.6 degrees, respectively. The mean change in the angle was 1.9 degrees in inclination of the device. The average horizontal migration was 1.0 mm, and the vertical migration was 2.0 mm. Only one hip showed substantial migration with breakage of the device. This failure case represented a large amount of posterior pelvic tilt in standing position postoperatively. The mean JOA hip score was increased from 46.7 to 74.8. Discussion. Poor outcome using Kerboull-type reinforcement plate with morsellised bone graft only has been demonstrated by many reports. In these literatures, bulk bone graft was recommended particularly in the case of large bone defect such as larger than half of the rounded plate of the device or more than 2 cm of thickness. In our case series, acetabular reconstruction using a Kerboull- type acetabular reinforcement device and bone graft gives satisfactory mid-term results even with morsellized bone graft only. One possible interpretation is that most of our cases had relatively small bone defect according to the staging of severity of the superior segmental bone loss made by Kawanabe et al. We suggest that the progressive posterior pelvic tilt should be considered to be a risk of poor outcome of the acetabular reconstruction using this device. To view tables/figures, please contact authors directly

Introduction

Failure of acetabular components has been reported to lead to large bone defects, which determine outcome and management after revision total hip arthroplasty (THA). Although Kerboull-type (KT) plate (KYOCERA Medical Corporation, Kyoto, Japan) has been used for compensating large bone loss, few studies have identified the critical risk factors for failure of revision THA using a KT plate. Therefore, the aim of this study is to evaluate the relationship between survival rates for radiological loosening and the results according to bone defect or type of graft.

Between 1993 and 2003, 67 consecutive revision total hip arthroplasties were performed in 65 patients, including 52 women and 13 men, using hydroxyapatite (HA) granules supported by a Kerboull-type reinforcement acetabular device. The average age at the time of index surgery was 68.6 years. The Acetabular bone loss according to the American Academy of Orthopaedic Surgeons (AAOS) system was type II for 7 hips, type III for 58 hips, and type IV for one hip. The Kerboull-type acetabular reinforcement device used was Kerboull Cross Plate in 18 hips and KT Plate in 49 hips. HA granules of sizes 0.9 to1.2 mm (G4) and 3.0–5.0 mm (G6) were mixed in a ratio of 1:1. Autografts were used to reconstruct the major segmental defects in 7 hips. At the time of this study 30 hips were lost of follow-up. Among 30 hips 22 hips were lost of follow-up because of the death of the patients. The remaining 37 hips were examined clinically and radiologically. The mean follow-up period of the series was 12.8 years. Complications were examined and clinical evaluation was done using Japanese Orthopaedic Association (JOA) hip score. The criterion for loosening of the acetabular component was cup migration exceeding 3 mm or angular rotation exceeding 3 degrees or breakage of the device. Among the entire series of 67 hips postoperative complications included dislocation in 3 hips, infection in 2 hips and revision in 4 hips. Two hips were revised for loosening and the other two hips were revised for infection. The JOA hip score increased from a mean value of 48.0 preoperatively to 76.8 at the last follow-up. Radiologically 5 hips were loose. Two hips among them were revised. Survival rate of the acetabular component at 10 years was 97.1% using acetabular revision for loosening as the end point and 90.6% using radiological loosening as the end point. Acetabular reconstruction with HA granules and a Kerboull-type acetabular device provided satisfactory clinical and radiographic results at 12.8 post-operative years

Introduction. For the total hip cases with severe bone defect, using acetabular reinforcement plate is one of effective method. But the shape of every defect is different. So it is very important to make it into proper shape. It would be not only time consuming but also the procedure requires many times trial insertion through the muscle which can be a cause big damage on it. To reduce the time and the damage, we have manufactured a chemical wood model for each case and shaped each acetabular reinforce plates. Materials and Methods. Three total hip cases, one primary case of rheumatoid arthritis with big bone absorption and 2 revision cases with big bone absorption were operated with acetabular reinforcement plate (LIMA Italy) shaped on their pelvic chemical wood model. Using Mimics®, CAT scan DICOM data were transferred STL CAD data. Then using Magics® chemical wood model was designed and manufactured by a compact CNC machine. Then each plate was bent and fitted for each defect 3-Dimensionally. Results. In all three cases, the acetabular reinforcement plates were inserted without any more shape modification. Discussion. It is very difficult to estimate how long the surgical time was saved and how much soft tissue damage was reduced. However, every preoperative shaping took more than 15 min even we can use not only plate benders but also vise and other tools. We had to check the plate fitting to the model at leased 10 times. Therefore, this procedure could be said that it has save at least 15 min and muscle damage for 10 times trial. For better estimation, we are going to record how long we need for the preoperative shaping and how many times we need to check fitting on the model

Conventional cemented acetabular components are reported to have a high rate of failure when implanted into previously irradiated bone. We recommend the use of a cemented reconstruction with the addition of an acetabular reinforcement cross to improve fixation. We reviewed a cohort of 45 patients (49 hips) who had undergone irradiation of the pelvis and a cemented total hip arthroplasty (THA) with an acetabular reinforcement cross. All hips had received a minimum dose of 30 Gray (Gy) to treat a primary nearby tumour or metastasis. The median dose of radiation was 50 Gy (Q1 to Q3: 45 to 60; mean: 49.57, 32 to 72). . The mean follow-up after THA was 51 months (17 to 137). The cumulative probability of revision of the acetabular component for a mechanical reason was 0% (0 to 0%) at 24 months, 2.9% (0.2 to 13.3%) at 60 months and 2.9% (0.2% to 13.3%) at 120 months, respectively. One hip was revised for mechanical failure and three for infection. Cemented acetabular components with a reinforcement cross provide good medium-term fixation after pelvic irradiation. These patients are at a higher risk of developing infection of their THA. . Cite this article: Bone Joint J 2015;97-B:177–84

Introduction. Massive defect of the acetabular bone is one of the severe situation in the hip arthroplasty. Installation of cup supporter or acetabular reinforcement device is one of the important method as well as big cup and bone graft etc. Preparing the device to be suitable shape is very important and installing it at the very position where the shaping was intended is also very important to obtain a stable condition for the arthroplasty. When we use navigation system, the device must be programmed in. But it is impossible to programme a device we have bended by ourselves into the system. If we can use a navigation system for such devices for those cases, we can expect better installation. We can fit the device on the patient's bone during the surgery of course; which is the ordinary procedure fot it; but it requires much time and tissue damage maybe with less accurate fitting. Materials and Methods. Two primary and three revision total hip arthroplasty cases with severe acetabular bone defect were treated with this method. First we have made chemical wood model for each case and bended the cup supporter on it. (Fig. 1) Then CAT scan of the model and the bended device on it were taken. Then the coordinate system of DICOM data set of the patient's original pelvis and the second DICOM data set i.e. the bended prosthesis were unified using MIMICS (Materialize, Belgium.) An STL format geometry data file of the bended device was extracted and merged into original DICOM dataset. Thus we could obtain a DICOM data set we call “predicted post-op DICOM.” During the surgery, a navigation system was used based on the predicted DICOM data. Result. Before installation of the device, navigation system could indicate pointer tip is expected to be device or not. After installation, touching the device by the pointer the system could tell if the device is in correct position or not. (Fig. 2) Using image merge of preoperative DICOM on post operative DICOM. The accuracy was very good. (Fig. 3)

Introduction. In the case of bipolar hemiarthroplasty, surgeons are often faced with only migration of outer head and severe osteolysis in acetabulum without loosening of femoral component. There has been much debate regarding the merits of removing or retaining stable femoral components in such cases. The purpose of this study was to determine whether revision of an isolated acetabular component without the removal of a well-fixed femoral component [Fig. 1] could be successfully performed. Materials and methods. Thirty-four hips of 33 patients who were followed up for a minimum of 1 year were examined. There were 29 women and 4 men. The average time from primary operation to revision surgery was 12.5 years (range, 0.0 to 17.9 years), and the average follow-up time after revision was 5 years (range, 1.1 to 15.2 years). The average age of the patients at the time of the index revision was sixty-four years (range, thirty-two to seventy-eight years). The reason for acetabular revision was migration of outer head in twenty-eight hips, disassembly of bipolar cup in four hips and recurrent dislocation in two hips. Of the thirty-four femoral components, twenty-seven were cementless and seven were cemented. In nine hips, we performed bone grafting to osteolysis of the proximal femur around the stem. Acetabular components were revised to an acetabular reinforcement ring with a cemented cup in 26 hips, to cementless acetabular components in 8 hips, and to cemented cup in 1 hip. Results. The average Japan Orthopaedic Association hip score improved from 50.7 to 86.1 points after revision surgery. One femoral component (3%) was revised because of periprosthetic fracture, three years after the index acetabular revision and eighteen years after the initial bipolar hemiarthroplasty. Radiographic evaluation of the thirty-three femoral components that were not revised demonstrated no evidence of loosening or subsidence. There were no dislocation or deep infection. Thirty-three (97%) of the acetabular components were judged to be stable at the final follow-up. A nonprogressive radiolucent line of less than 2 mm was observed in one case. Conclusion. We recommend that isolated acetabular revision be considered in cases of failed bipolar hemiarthroplasty with a well-fixed femoral component

Purpose. Complete wear-out of Polyethylene (PE) liner results in severe metallosis following articulation of the artificial head with the acetabular metal shell. We postulated that an adverse response can be led to surrounding bone tissue and new implant after revision surgery because the amount of PE wear particle is substantial and the metal particles are infiltrated in this catastrophic condition. We evaluated clinical characteristics and the survival rate of revision total hip arthroplasty (THA) performed in patients with severe metallosis following failure of PE liner. Materials and Methods. Between January 1996 and August 2004, severe metallosis following complete wear-out of PE liner were identified during revision THA in 28 hips of 28 patients. One patient had died at 7 days after surgery and 3 patients could not be reached at 5 year follow-up. Twenty-four hips of 24 patients (average age, 47.5 years) were followed for at least 6.5 years (average, 11.3 years; range, 6.5–15.9 years) and were evaluated. The mean time interval between prior surgery and the index revision surgery was 9.6 years (range, 4.0–14.3 years). The indications for revision surgery were osteolysis around well-fixed cup and stem in 22 hips and osteolysis with aseptic loosening of the cup in 2 hips. Bubble sign was observed on preoperative radiograph in 10 hips. Total revision, cup revision, and solitary bearing change were performed in 13, 10, and one hip respectively. A cementless implant was used in 23 hips and acetabular reinforcement ring was used in one. Clinical evaluation was performed using Harris hip scores and Kaplan-Meier survival analysis was performed. Multivariate analysis was performed with age, gender, BMI, bone defect type, existence of bubble sign and type of revision surgery as variables to evaluate the association with osteolysis or loosening. Results. One patient who had died from an unrelated medical condition at 6.5 years had hip that were functioning well at the time of death. Average Harris hip score improved from 64.5 points preoperatively to 81.9 points at the last follow-up. Wear and osteolysis were detected at average 8.9 years (3.1–13.5 years) after revision in 14 hips. Acetabular cup was loosened in 9 hips. Re-revision of cup was performed in 5 hips and re-revision of both cup and stem was done in 2 hips. In another hip, cup removal and artificial neck cutting was performed due to severe bone loss following two times of cup re-revision. With radiographic evidence of osteolysis as the end point, the 15-year survival rate was 35.3% (95% confidence interval [CI], 11.6%–59.0%). With radiographic loosening of any implant as the end point, the 15-year survival rate was 54.0% (95% CI, 27.9%–80.1%). Multivariate analysis revealed no variable that had a significant association with osteolysis or loosening. Conclusion. The survival rate of revision THA in patients with metallosis following a failure of a PE liner was low. Substantial amount of PE wear debris and the infiltration of metallic wear particles in the periprosthetic tissues might lead to progressive bone loss and implant loosening after revision THA

Total hip arthroplasty for developmental dysplasia of the hip (DDH) remains a difficult and challenging problem. How to reconstruct acetabular deficiencies has become increasingly important. One of the major causes inducing loosening of acetabular reinforcement ring with hook (Ganz ring) is insufficient initial stability. In this study, three-dimensional finite element models of the pelvis with different degrees of bone defect and acetabular components were developed to investigate the effects of the number of screws, screw insert position (Fig. 1), and bone graf quality on the initial stability under the peak load during normal walking. The size of pelvic bone defect, the number of screws and the position of screws were varied, according to clinical experience, to assess the change of initial stability of the Ganz ring. The Ganz ring was placed in the true acetabulum and the acetabular cup was cemented into the Ganz ring with 45 degrees abduction and 15 degrees of screws. The Insert position, nodes on the sacroiliac joint and the pubic symphysis were fixed in all degrees of freedom as the boundary condition. The peak load during normal walking condition was applied to the center of the femoral head (Fig. 2). According to the Crowe classification, as the degree of acetabular dysplasia was increased, the relative micromotion between the Ganz ring and pelvis was also increased. The peak micromotion increased as the stiffness of bone graft decreased. Increasing the numbers of screws, the relative micromotion tended to be reduced and varied the screw insertion position that affects the relative micromotion in the Ganz ring-pelvic interface (Fig. 3). This study showed that increasing the number of inserted screws can reduce the relative micromotion. Both the insert position and graft bone property affect the stability of the Ganz ring while the insert position has a greater impact. The current study is designed to lay the foundation for a biomechanical rationale that will support the choice of treatment

INTRODUCTION. Progressive polyethylene wear is associated with the occurrence of osteolysis, which can lead to component loosening and subsequent revision. Massive wear of the polyethylene liner may result in the penetration of the femoral head through the metal shell. Although metallosis after total hip arthroplasty has been well documented in the literature, extensive metallosis with polyethylene wear-through has been only sparsely described. The purpose of the present study was to assess clinical findings and the results of revision total hip arthroplasty in these cases. METHODS. We evaluated seven hips in five patients who underwent revision total hip arthroplasty because of metallosis with polyethylene wear-through. The average age of the patients at the time of hip revision was 70.1 years. There were granulomatous cysts surrounding the hip joint and osteolysis in the greater trochanter or in the acetabulum. Eroded metal shells with worn-through polyethylene were exchanged. Kerboull-type acetabular reinforcement device were used in five hips and GAP cup in two. Distal interlocking femoral stems were used in four hips and extensively porous-coated stems in two. All cases with osteolysis were in addition treated with bulk or morselized allograft bone. The mean duration of follow-up was 3 years. RESULTS. At the time of final follow-up evaluation, none of the hips showed osteolysis. Stable fixation of femoral and acetabular components was achieved in all cases. Bulk allograft bone was resorbed in two cases, but in all other cases grafted bones were united and improve bone stock. CONCLUSIONS. Metallosis with polyethylene wear-through caused severe synovitis and massive osteolysis. Although debridement of the surrounding metallic stained tissue could not be completely done, the clinical result of revision surgery was favorable

Introduction. This study was performed to evaluate the minimum 5-year clinical and radiological results of liner cementation into a stable acetabular shell using a metal-inlay, polyethylene liner during revision total hip arthroplasty (THA). Methods. Sixty-six hips (63 patients) that underwent revision THA using a metal-inlay polyethylene liner cementation were included. The causes of revision were; polyethylene wear in 37 cases, femoral stem loosening in 20 cases, ceramic head fracture in 4 cases, and recurrent dislocation in 5 cases. Clinical results were graded at final follow-up using Harris hip scores, and radiographs were evaluated to determine acetabular component inclination, the stabilities of acetabular and femoral components, correction of hip centers, and the progression of osteolysis. Results. The average follow-up was 87.3 months (range 60.1∼134.3). Mean Harris hip scores improved from 64 preoperatively to 87.6 at final follow-up. Seven cases (10.6%) of dislocations occurred after revision surgery and 2 cases (3.0%) underwent acetabular revision or soft tissue augmentation. One cemented liner (1.5%) was dislodged and acetabular revision was performed using an acetabular reinforcement ring and a morselized bone graft. Two cases (3.0%) developed an infection and both underwent debridement and prosthesis with antibiotic-loaded acrylic cement (PROSTALAC) and intravenous antibiotics. Radiographic evaluations revealed osteolytic progression in the acetabular cup in 3 cases and osteolytic progression at the femoral stem in 7 cases, but none of these 10 cases underwent revision of the acetabular or femoral component. No cases of metallosis, metallic hypersensitivity, or cancer were encountered. Conclusion. This study shows that liner cementation into a stable metal shell provides relatively good clinical results. This technique offers lower surgical morbidity, a short operation time, and rapid patient recovery. Summary. Good clinical and radiologic outcomes were obtained at more than 5-years after liner cementation into a stable acetabular shell using a metal-inlay polyethylene liner during revision THA

Introduction: While an increasing number of authors have reported on the long-term results of primary alumina total hip arthroplasty (THA) [. 1. ], strategies for revising a ceramic-on-ceramic THA are debated in the literature. According to some authors [. 2. ], the reimplantation of a ceramic head on a well-fixed femoral stem is inadvisable, as it may lead to a fracture of the newly implanted head. The aim of the present study was to evaluate the incidence of this specific issue, and to report on the clinical and radiological results of the revised hips. Methods: Between January 1977 and December 2005, 138 consecutive alumina-alumina revision hip arthroplasties were performed in 127 patients. There were 79 women (62.2%) and 48 men (37.8%), with an average age of 67 years (range, 32–91 years). Among these, an isolated acetabular revision was performed in 108 cases. The reason for revision was aseptic loosening of the acetabular component in 98 hips, pain in 7, fracture of an alumina liner in 2, and recurrent dislocation in 1. The revised socket was a cemented alumina in 56 hips, a threaded screw-in titanium with an alumina core in 34, a pressfit titanium with an alumina core in 11, and bulk alumina in 7. Acetabular bone stock losses were classified according to the AAOS system. Most of the hips had a contained type II defect (86%). In all cases, the femoral stem was left in place and the acetabular component alone was revised. At the time of revision surgery, an aluminaalumina combination was implanted in 27 hips, an aluminapolyethylene combination in 56, a metal-poly-ethylene combination in 15, and a zirconia-polyethylene in 10. Overall, a ceramic head was reimplanted on a used femoral taper in 59 cases. Acetabular reconstruction with allografts supported with the Kerboull acetabular reinforcement device was performed in 31% of the hips. Results: The mean follow-up period was 78 ± 37 months. Thirteen patients (15 hips) died a mean 37 months after surgery. Sixteen patients were lost to follow-up. Postoperatively, five hips had a recurrent dislocation, 2 a deep infection, 9 a trochanteric nonunion (21,3%), 6 a transient nerve palsy. 18 hips required a re-revision surgery, 12 of which for aseptic loosening of the acetabular component. Among the 59 ceramic heads implanted on a well-fixed stem, no fracture of the head occurred at a mean 81 months follow-up. Of the original 108 hips, 77 were available for clinical evaluation and 75 for radiological evaluation at least 2 years after surgery. The mean Merle d’Aubigné score increased from 10.1 ± 2.1 to 16.7 ± 1.1 at the latest follow-up (p< 0.001). Forty-five hips were graded excellent or very good (60%), 26 good (34,6%), 3 fair (4%), and 1 poor (1.3%). When revision for aseptic loosening was considered as a failure, the overall survival rate at 8 years was 96.3 ± 1.8%. Discussion & Conclusions: In the present study, aseptic loosening of the acetabular component was the main reason for revision surgery. Osteolysis around ceramic implants was moderate and was related to the migration of the socket. Among the ceramic heads implanted on a used titanium trunnion, no fracture was observed. This approach is possible, in so far as careful inspection does not show any major imperfection of the morse taper [. 3. ]. As for other bearing surfaces, the management of aseptic loosening of al-al prostheses is based on the amount of osteolysis around the loosened socket

We wanted to evaluate the clinical and radiological results of acetabular revision using the acetabular reinforcement ring and allograft impaction in patients with severe acetabular bony defect. 41 hips revision arthroplasty using reinforcement ring were performed between April 1997 and October 2005 and were followed up for more than two years. The cause of primary arthroplasty was AVN in 18 cases, secondary osteoarthritis (OA) in 17 cases, fracture in cases and primary OA in 1 case. The cause of revision arthroplasty was acetabular cup loosening in 20 cases, massive osteolysis in 14 cases, infection in 4 cases, liner dissociation in 2 cases, and recurrent dislocation in 1 case. The average period between primary and revision arthroplasty was 11.4 years (range 0.6 to 29.1 years). Acetabular defects were classified based on the AAOS classification and Paprosky classification system. All were treated with autografts or allografts. Muller ring was used in 18 cases, Burch-Schneider ring was used in 14 cases, and Ganz ring in 9 cases. Clinical evaluations were performed according to the Harris hip score (HHS), and the radiographic results were evaluated by progression of acetabular component loosening, union of bone grafts, periacetabular osteolysis, and migration of the hip center. The mean preoperative Harris hip score of 64.9 was improved to 91.8 points at the latest follow-up. There were 39 cases of type 3 defect, 2 cases of type 4 defect according to the AAOS classification and 8 cases of type 2B defect, 3 cases of type 2C defect, 28 cases of type 3A defect, and 2 cases of type 3B defect according to Paprosky classification. Radiographically, the bone grafts were well united except one case. The mean preoperative hip center of rotation which was vertically 32.3mm, horizontally 33.2 mm migrated to vertically 26 mm, horizontally 33.2 mm postoperatively and it was statistically significant. The mean preoperative abductor lever arm of 41.7 mm changed to 45 mm postoperatively which was statistically insignificant. However the mean preoperatiave body lever arm of 89.4 mm changed to 96.9 mm postoperatively which was statistically significant. Postoperative complications were cup loosening in 1 case, dislocation in 2 cases, and recurrence of deep infection in 1 case. Clinically and radiographically, acetabular reconstruction using reinforcement ring showed very promising short term result. We conclude that reinforcement ring can provide stable support for grafted bone in severe bone defect. But meticulous surgical technique to get initial firm stability of ring and optimal indication in mandactory for the successful result

The purpose of this study was to define immediate post-operative ‘quality’ in total hip replacements and to study prospectively the occurrence of failure based on these definitions of quality. The evaluation and assessment of failure were based on ten radiological and clinical criteria. The cumulative summation (CUSUM) test was used to study 200 procedures over a one-year period. Technical criteria defined failure in 17 cases (8.5%), those related to the femoral component in nine (4.5%), the acetabular component in 32 (16%) and those relating to discharge from hospital in five (2.5%). Overall, the procedure was considered to have failed in 57 of the 200 total hip replacements (28.5%). The use of a new design of acetabular component was associated with more failures. For the CUSUM test, the level of adequate performance was set at a rate of failure of 20% and the level of inadequate performance set at a failure rate of 40%; no alarm was raised by the test, indicating that there was no evidence of inadequate performance.

The use of a continuous monitoring statistical method is useful to ensure that the quality of total hip replacement is maintained, especially as newer implants are introduced.

We retrospectively reviewed 40 hips in 36 patients who had undergone acetabular reconstruction using a titanium Kerboull-type acetabular reinforcement device with bone allografts between May 2001 and April 2006. Impacted bone allografts were used for the management of American Academy of Orthopaedic Surgeons Type II defects in 17 hips, and bulk bone allografts together with impacted allografts were used for the management of Type III defects in 23 hips. A total of five hips showed radiological failure at a mean follow-up of 6.7 years (4.5 to 9.3), two of which were infected. The mean pre-operative Merle d’Aubigné score was 10 (5 to 15) vs 13.6 (9 to 18) at the latest follow-up. The Kaplan-Meier survival rate at ten years, calculated using radiological failure or revision of the acetabular component for any reason as the endpoint, was 87% (95% confidence interval 76.3 to 97.7). A separate experimental analysis of the mechanical properties of the device and the load-displacement properties of bone grafts showed that a structurally hard allograft resected from femoral heads of patients with osteoarthritis should be preferentially used in any type of defect. If impacted bone allografts were used, a bone graft thickness of < 25 mm was acceptable in Type II defects. This clinical study indicates that revision total hip replacement using the Kerboull-type acetabular reinforcement device with bone allografts yielded satisfactory mid-term results

Introduction: Treatment of acetabular defects can be difficult, especially in case of roof destruction. Since 9 years, we use a variant of Paprosky’s technique which consists in rebuilding the roof by structural allograft and acetabular reinforcement ring. The purpose of this study is to present this technique and the follow up results. Patients: This retrospective study concerns 21 patients (23 hips) with severe acetabular bone loss (8 cases of stage 2 and 15 cases of stage 3 of Paprosky): 4 septical and 19 aseptical loosening. Between 1998 and 2005, all patients were operated with the same surgical technique using an allogeneic structural allograft (femoral head or distal femur) and an acetabular reinforcement ring (20 of KERBOULL, 3 of GANZ) associated with a cemented PE cup. Method: Review included a clinical and X-ray evaluation (analysis of the refocusing of the hip, the positioning and the stability of implants and the graft incorporation). Results: Mean duration of follow-up is 3,5 years [1–8,3]. Preoperative PMA score rised from 6,6 [0–12] to 15,8 [12–18] in postoperative. There was no peroperative complication. After surgery, 2 cases of early hip dislocation required PE block; 2 cases of sepsis were treated, one by washing and one by a surgical revision. In 60% of cases, immediate total weight bearing was allowed. The immediate postoperative X-rays showed that the rotation center of the hip was 5,2 mm [0–10] far from the ideal rotation center (26% of cases: 0 mm) and the PE cup was implanted with a lateral inclination of 42,5° [30–55]. In postoperative X-ray follow up, one case of acetabular aseptic loosening was found which didn’t need hip revision. In all other cases no modification of implants position neither of hip rotation center was noted. In 79% of cases, we had total graft incorporation; in 17% of cases, an non evolutive radiolucent area between graft and bone and in 4% of cases (loosening) a graft migration. Conclusion: The use of a structural allograft combined with acetabular reinforcement ring allows hip reconstruction in severe acetabular bone loss with good medium term results

Acetabular components of total hip joint replacement (THJR) in previously irradiated pelvis show high rates of failure. We present a literature review and a retrospective series evaluating the survival of acetabular cages in this difficult situation. Our hypothesis was that cage reinforcement of the acetabulum after previous pelvic irradiation would lead to early failure. A cohort of 11 patients (12 hips) was identified, who had undergone THJR utilising an acetabular cage, after previous pelvic irradiation for malignant tumours. All operations were performed by a single surgeon in Waikato over the period of 1997–2007. Six patients (six hips) died within one year of their operation, the further five patients (six hips) were analysed for survival and radiograpical loosening of the acetabular component. Complications attributed to previous irradiation are also reported. There is a paucity of literature of THJR survivorship after pelvic irradiation. The first series from the 1970’s showed 50% acetabular loosening at 5 years in cemented cups. Two conflicting series are published with 44% vs. 0% failure of uncemented cups. Only one previous series (22 hips) reports the use of acetabular reinforcement rings, and showed a 20% loosening and 10% deep infection rate at 4 years. In our cohort of 12 hips in 11 patients, only five patients survived greater than one year after joint replacement. The average follow up of the remaining six hips is five years (two to ten years). Two out of six of the acetabular cages have catastrophically failed. Of the remaining four cages, one is probably, and three are possibly radiologically loose. Two out of six have raised concerns in regards to deep infection that were not proven microbiologically. Overall of the patients who survived greater than one year after their THJR for pelvic irradiation, only four out of six of the acetabular cages remained insitu, and all had concerns raised in regards to radiographical loosening. We report a high rate of clinical and radiographic failure of cage reconstruction of the acetabulum after previous pelvic irradiation. A superior method of acetabular reconstruction in this difficult situation is yet to emerge. Alternative methods of reconstruction continue to develop, with trabecular metal options a possible consideration