Introduction: There has been a proliferation of newer fluted tapered grit-blasted titanium stems in hip revision arthroplasty. However, only a limited number of clinical series have so far been reported in the literature. Moreover, all reports have only a short-term clinical and radiographical follow-up (< 5 years). Medium-term and long-term follow-up studies are lacking. Therefore, the aim of this study was to review a series of a cementless modular tapered revision femoral component (MP Link hip reconstruction prosthesis) with a minimum 5 year follow-up. Patients and Methods: This study includes 90 consecutive cases (87 patients) with the MP stem. We documented the Harris hip score (HHS) and the Visual analogue scale (VAS) was used to assess pain at rest and movement. Survivorship was calculated using Kaplan-Meier survival analysis. The 95% confidence intervals (CI) for the cumulative 5 year survival were calculated. Radiographs made immediately after the index operation were compared with those at follow-up examination in order to classify the restoration of femoral bone and vertical migration of the implant. Results: Of the original 90 cases, 24 (27%) died prior to clinical and radiographical review, 2 (2%) had a stem revision and 1 (1%) was lost to follow-up. Patients who died and were lost to follow-up were included in the survival analysis. For those patients, all data concerning complications and revisions were extracted from journal files and the Swedish Hip Register which collects all information on reoperations after hip revision surgery. The median follow-up time was 6 (5–11) years. The median VAS for pain for the affected hip was 0 (0–5) at rest and 0 (0–9) at movement. The median HHS at follow-up was 78 (16–100) points. 17 (19%) patients dislocated their hips during follow-up. A prosthesis head size of 22 mm was present in 6/17 (35%) patients with dislocation and in 11/73 (15%) patients without dislocation (P = 0.055). The cumulative 5 year survival rate was 98% (95% CI: 94–100%) with stem removal and 90% (95% CI: 85–96%) with any reoperation as the endpoint. At follow-up, we noted subjectively that 17% of the cases had evidence of proximal bone restoration, whereas 44% had constant defects. In 39% the quality of the proximal bone appeared to be declining. If present, this was mostly seen around the lesser trochanter. The median vertical stem migration was 2.7 (0–30) mm. Discussion: This is the first report with a clinical and radiographical medium-term follow-up of patients with a cementless modular tapered distally fixated hip revision stem. In our study, we found a discrepancy between a high implant survivorship and good pain relief on one hand and a high dislocation rate on the other hand

Xenografts of bovine bone were used successfully for years with a minimum acceptable rate of side effects in total hip revision arthroplasty for filling large bone defects. The great majority of them was withdrawn from the market when any biological product of bovine origin was considered as a potential carrier of prions infection. However, current EEC regulations permit their surgical therapeutic use if obtained from cattle under 6 months of age, which are supposed to be not at risk of prion transmission. Lubboc, a purified trabecular bone matrix containing only type-1 collagen and hydroxyapatite, fulfils this requirement. From 2001 to 2003 we used this product in fragments (chips) to fill bone defects of the acetabulum before screwing the acetabular rings in 37 patients. No massive grafts were implanted. Minimum follow-up was 12 months, maximum 27 months. Four subjects were lost to follow-up. The fate of the grafts was evaluated for evidence of union, remodelling, resorption, migration of the rings or fracture of the newly formed bone. No significant adverse events were registered. If the risk of transmitting infectious agents is excluded or minimised according to the present legislation, it seems unjustified to remove xenografts from the options available to orthopaedic surgeons, considering the problems of bone stock deficiency and reconstruction in hip arthroplasty revision surgery

This study aimed to verify the hypothesis that an antibiotic loaded hydrogel, defensive antimicrobial coating (DAC), reduces overall complication and infection rates when used for high-risk primary and revision total hip arthroplasty (THA).

This was a retrospective study matched cohort study of 238 patients, treated with cementless implants with and without DAC. A sub-group analysis of patients undergoing 2nd stage revision THA for prosthetic joint infection (PJI) was also conducted. Re-infection rates within 2 years, complications necessitating surgical intervention and radiographic analysis for aseptic loosening was assessed.

The mean age was 68.3±11.5 years, with 39 (32.8%) Macpherson class A, 64 (53.8%) class B and 16 (13.4%) class C patients. 4 (3.4%) patients in the DAC group developed complications including 1 PJI and 1 delayed wound healing, while 13 (10.9%) patients in the control group developed complications including 5 PJIs and 3 delayed wound healing (p=0.032). PJI rates (p=0.136) and delayed wound healing rates (p=0.337) were not statistically significant. For 2nd stage revision THA for PJI there were 86 patients in the DAC group and 45 in the control group. 1 (1.2%) patient in the DAC group developed complications with no recurrences of infection or delayed wound healing, while 10 (22.2%) patients in the control group developed complications including 4 recurrent PJI and 1 delayed wound healing (p=0.003). Recurrent PJI rates were statistically significant (p=0.005) while delayed wound healing rates were not (p=0.165). Patients treated with DAC also had lower rates of aseptic loosening (0% vs 6.7%; p=0.015).

Antibiotic impregnated hydrogel coatings on cementless implants showed decreased complication rates after complex primary or revision THA. In 2nd stage revision THA for PJI, it was associated with reduced risk of re-infection and aseptic loosening.

Introduction

Dual mobility (DM) total hip arthroplasty (THA) prostheses are designed to increase stability. In the setting of primary and revision THA, DM THA are used most frequently for dysplasia and instability diagnoses, respectively. As the use of DM THA continues to increase, with 8,031 cases logged in the American Joint Replacement Registry from 2012–2018, characterizing in vivo damage and clinical failure modes are important to report.

Aims

The aim of this study was to assess the incidence the microbiological spectrum and clinical outcome of hip and knee revision arthroplasties with unexpected-positive-intraoperative-cultures (UPIC) at a single center with minimum follow up of 2 years.

In severe cases of total knee & hip arthroplasty, where off-the-shelf implants are not suitable (i.e., in cases with extended bone defects or periprosthetic fractures), 3D-printed custom-made knee & hip revision implants out of titanium or cobalt-chromium alloy represent one of the few remaining clinical treatment options. Design verification and validation of such custom-made implants is very challenging. Therefore, a methodology was developed to support surgeons and engineers in their decision on whether a developed design is suitable for the specific case. A novel method for the pre-clinical testing of 3D-printed custom-made knee implants has been established, which relies on the biomechanical test and finite element analysis (FEA) of a comparable clinically established reference implant. The method comprises different steps, such as identification of the main potential failure mechanism, reproduction of the biomechanical test of the reference implant via FEA, identification of the maximum value of the corresponding FEA quantity of interest at the required load level, definition of this value as the acceptance criterion for the FEA of the custom-made implant, reproduction of the biomechanical test with the custom-made implant via FEA, decision making for realization or re-design based on the acceptance criterion is fulfilled or not. Exemplary cases of custom-made knee & hip implants were evaluated with this new methodology. The FEA acceptance criterion derived from the reference implants was fulfilled in both custom-made implants and subsequent biomechanical tests verified the FEA results. The suggested method allows a quantitative evaluation of the biomechanical properties of custom-made knee & hip implant without performing physical bench testing. This represents an important contribution to achieve a sustainable patient treatment in complex revision total knee & hip arthroplasty with custom-made 3D printed implants in a safe and timely manner.

We developed an endoscopically controlled device for cement removal out of the femoral canal. This system (Swiss OrthoClast) uses simple ballistic principles to effect mechanical fracturing of the bone cement. A special extraction set facilitates removal of the distal cement layer and of the intramedullary plug. The cement removal procedure, even in the depth of the femur, is controlled with an endoscopical system via monitor. Handling of this device will be demonstrated. We report our clinical results of 45 procedures with this device.

Material and methods: 45 patients (14 male ,31 female, average age at revision 72.9 years) were revised after an average follow-up period of 91.2 months (range 0-252 months) after primary THR due to mechanical loosening (n=38) or infection (n=7). All procedures were analysed and evaluated with a standardized documentation.

Results: 90% of the revisions showed type 1 bone defects according to Paprosky’s classification. In all but three cases cement removal with this method was complete. We saw one case of femoral fissuration in a patient with osteoporosis and one cortical perforation while drilling in the K-wire of the extraction tool. The time for cement removal varied between 5 and 75 minutes with an average of 27.1 minutes in the aseptical and 36.9 minutes in the septical group. Only in the very first cases we had problems with the endoscopic view.

Conclusion: Swiss OrthoClast facilitate cement removal out of the femur and avoids cortical fenestration. The optical system is effective and helpful, even for extraction of the distal cement layer and the medullary plug. This mechanical system has no side effects like development of heat, dust or toxic products during cement removal. Disadvantages might be the learning curve for the surgeon and its costs.

Aims: The bone – conductive proparties of hydroxyapatite (HA) coatings are attractive in revision surgery with bone loss. The purpose of this study is to analyse the clinical and radiological results of 55 cases of revision hip arthroplasty using hydroxyapatite femoral stems. Methods: Between May 1995 and October 2000 we performed 55 patients total hip replacements in 50 patients (5 bilateral) using hydroxyapatite (HA) – coated femoral stem. The average age of the patients at the time of the index revision was 67 years (range 44–84). Clinical evaluation was by a Merle d’Aubigne Score (preoperative 6.54 points). Radiological evaluation used the AAOS system for preoperative films and scaring system after Engh for the postoperative films. Bone grafts was required in 35 cases. Results: Postoperative Merle d’Aubigne score was 17.25 points. Complications: 3 dislocations, one transitory nerve palsy and 14 associated intraoperative fractures. All grafts consolidated. None of the femoral stem components required revision because of aseptic loosening. No radiologically progressive lucency or signs indicating a loose implant were visible in anycases. There were no cases of femoral stem migration. Conclusions: We conclude that the hydroxyapatite femoral stem is suitable for implantation at revision hip arthroplasty and can give good results in the short to medium term, because the clinical and radilogical results are excellent, with a early consolidate fractures.

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).

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.

Aim of the study: Results of total hip replacement in consideration of quality of life and their correlation to clinical radiologic findings were examined.

Material and methods: 46 of 61 patients with aseptic loosing and total hip replacement were examined in average 4,3 years after surgery with the Harris Hip Score, Merle d’Aubigne Score, Postel Score, WOMAC-Score and SF-36 Health Survey Score. The study of radiographs was completed by the Scores of Brooker, Lee and Gruen. Allograft were used in 38 (83,6%) cases.

Results: The result of the Merle d’Aubigne Score and Postel Score in average account for 11,5 points. Harris Hip Score obtains 62,7 points. The comparison form patient and control group with the SF-36-Score shows unpropitious results particularly for physical functioning, roll limitation because of physical health problems and roll limitation because of physical emotional problems. The outcome for general mental health and vitality show better results for the patients as for the control. Evaluation of the physical and psychical scale applies to impairments of daily life depending on the disease. Patients with hip arthroplasty shows in comparison to patients with cancer or cardiac infarction worst results for the physical category, whereas the best results for the psychical category. Radiographs of 33 patients were completely evaluated. In eight cases (24,2%) there were loosening lines in femur shaft area. In 18 cases (54,55%) there were loosening lines in the area of the acetabular cup, in three cases (9%) a migration

Conclusion: After a total hip replacement the physical functions are limited. Primary hip arthroplasty for young patients should be indicated reserved in consideration of above mentioned results, even if psychological results surprised.

Aim. In the diagnosis of prosthetic joint infection (PJI), many biomarkers have shown a sound performance in terms of accuracy, sensitivity and specificity. In this study we aimed to test the frequently used serum biomarkers C-reactive Protein (CRP), Fibrinogen, Leukocytes, Interleukin-6 (IL-6), Interferon alpha (IF-alpha) and Procalcitonin (PCT) regarding these qualities. Following that, the optimal multi-biomarker combination was calculated to further improve the diagnostic performance. Method. 124 knee or hip revision arthroplasty procedures were prospectively investigated focusing on preoperative serum blood levels of CRP, Fibrinogen, Leukocytes, IL-6, IF-alpha and PCT. The presence of PJI was determined by a blinded researcher. Logistic regression with lasso-regularization was used for the biomarkers and all their ratios. Following cross-validation on a training sample set to get optimal performance estimates, we performed the final model on a test set (25% of all samples). Results. Out of all evaluated biomarkers, CRP (AUC 0.91, p-value 0.03) and Fibrinogen (AUC 0.93, p-value 0.02) had the best performances. The optimal combination when testing multiple biomarkers in 32 cross-validation runs was calculated including Fibrinogen, CRP, the ratio of Fibrinogen to CRP and the ratio of serum Thrombocytes to CRP (AUC 0.92, accuracy 0.77, specificity 0.92, sensitivity 0.68, cut-off 0.63, p-value 0.04). Conclusions. It was not possible to increase the diagnostic performance by combining multiple biomarkers using sophisticated statistical methods. The calculated Multi-biomarker models did not improve the AUC, accuracy, sensitivity and specificity when compared to single biomarkers

Introduction: The histology of prosthetic tissue is a gold standard for the diagnosis of prosthetic joint infection. However, the specificity and sensitivity of histology has never been 100% and this could be due to several causes. A possible cause for inconsistencies in histological results could be the type of specimen submitted to laboratory. The majority of authors obtain specimens from pseudocapsule, interface membrane and any tissue area suspicious of infection. Aim: The objective of our study was to elucidate which is the most accurate specimen for histological diagnosis of prosthetic joint infection. Methods: Prospective study including all revision arthroplasties performed in Hospital Clinic of Barcelona (Spain) from January 2007 to June of 2009. Specimens from pseudocapsule and from interface membrane were obtained from each patient. Definitive diagnosis of infection was considered when ≥2 cultures were positive for the same microorganism or the presence of pus around the prosthesis. Patients were classified in two groups:. patients submitted to hip revision arthroplasty due to an aseptic loosening in whom cultures (at least 5) obtained during surgery were negative and. patients submitted to hip revision arthroplasty due to a septic loosening confirmed by the presence of pus or ≥2 positive culture for the same microorganism. Results: A total of 69 revisions were included in the study; 57 were classified in the group A and 12 were classified in the group B. The percentage of positive interface membrane histology in patients with prosthetic joint infection (group B) was significantly higher than the percentage of positive pseudocapsule histology (83.3% vs 41.6%, p=0.04, Fisher exact test). Conclusion: The results suggest that the best specimen of periprosthetic soft tissue for histological study to diagnose the chronic periprosthetic infection in a revision total hip arthroplasty is the periprosthetic interface membrane

Background: The use of impacted morselized allograft bone and cement in hip revision arthroplasty has proved to be a useful technique for reconstructing femoral bone stock. Studies that specifically address intraoperative and early postoperative femoral fractures and their relationship with bone deficiency, surgical approach or events, fixation of removed implant as well design of implanted stem have been scarce. Methods: Two hundred and eighty five consecutive hip revision arthroplasties with impacted morselized allograft bone were studied. Clinical and radiographic follow-up evaluation was performed and all kind of femoral fractures and incidental perforations during the surgery and within the first year after were analysed. Results: Sixty four (22,4 %) femurs were affected with an incidental perforation or fracture during the surgery and within the first year after. Intraoperative fracture was present in forty femurs. Twenty three were diaphyseal vertical cracks, eight proximal vertical cracks, four fractures of the greater trochanter and two complete diaphyseal fractures. Incidental femoral perforation was present in twenty five femurs. Six fractures occurred during the first year. Four patients of the femoral incidental perforation group suffered a complete diaphyseal fracture at the perforation level. No patient with a diaphyseal femoral crack suffered a complete diaphyseal fracture. Two additional complete fractures occurred during the first year without previous intraoperative complication. Multivariate analysis showed the risk factors for femoral fractures during or after revision to be grater according to preoperative deficiency of the femoral bone stock, or the presence of an intraoperative femoral perforation. Vertical cracks, surgical approach, removal of a cemented or uncemented stem as well as design of the implanted stem showed no difference regarding this complication. Conclusions: Even though a high rate of femoral complications (22,4 %) was observed we found that vertical cracks regardless their location and trochanteric fractures (12,2%) account for almost all of them but have no clinical relevance. Incidental perforation occurred in 9% of the cases and it was found to be related to complete femoral fractures as well as bone stock deficiency. This serious complication requiring revision occurred in only 2.8% of the cases. Due to this results we encourage the use of this technique

Modular femoral stem provides significant flexibility in total hip revision arthroplasty. There have been few clinical studies that have dealt with modular stem. We have evaluated the clinical and radiographic performance of 59 patients with distal fix modular Link MP stem. The average follow-up period was 6.4 years. The average Harris hip score was improved from 47 to 87.6. Of 19 patients with trochanteric osteotomy, greater trochanter was displaced in four patients. Re-revision was done to five patients. Three were for subsidence, one of them showed dissociation of the coupling part and the other two were for a nonunion of osteotomy site. There was no statistical relation (p=0.40) between stem subsidence and bone deficiency; the subsidence may have been too small for the canal. As a result of last follow-up, survival rate was 91.5 %(CI 95%, 89–101), but there was no case of recurrent dislocation or femoral stem fracture

Background: The aim of this prospective multi-center study was to evaluate the clinical and radiological results of a total of 314 uncemented femoral stem revisions using the modular MRP-titanium system. Methods: 305 patients (111 males, 194 females, mean age 67.7) with 314 MRP-titanium systems were followed-up for a meantime of 3.2 years (1 to 9 years). Pre- and post-operatively all patients were clinically documented using the Harris hip score. Radiologically, the preoperative bony defects were assessed by the Paprosky classification. Post-operatively, periprosthetic bone remodeling was evaluated on the basis of radiographic evidence of bone apposition or resorption. The modular MRP-titanium system has proven to be valuable in quite problematic cases of hip revision arthroplasty with extensive femoral defects. The system allows intraoperative adaptation of implant length and antetorsion angle to the actual situation, a feature not provided by non-modular femoral revision implants

Aim. The saddle prosthesis was originally developed for reconstruction of large acetabular defects in hip revision arthroplasty. Later on the saddle prosthesis was also used for hip reconstruction after resection of peri-acetabular tumours. In case of patient survival a long-term good hip function is required of the saddle prosthesis. The goal of this study is the measurement of long-term clinical results of saddle prosthesis after reconstruction of peri-acetabular tumours. Method. Between 1987 and 2003 a total of 17 patients were treated in the Leiden University Medical Center with saddle prosthesis after resection of peri-acetabular tumours (12 chondrosarcoma, 3 osteosarcoma, 1 malignant fibrous histiocytoma, 1 metastasis). 11 of the 17 patients died, the mean survival was 37 months (range 2-59 months), and 6 patients were still alive (follow-up 12.1 year, range 8.3–16.8 year). The outcome was measured with the SF-36 questionnaire, the Toronto Extrimity Salvage Score (TESS) and the Musculo Skeletal Tumour Society (MSTS) score. In 1 patient the saddle prosthesis was removed already after 3 months because of luxation and infection. Results. In 13 of the 17 patients the use of walking devices was known: 54% required two crutches, 38% one crutch, and 8% no walking aids. The mean hip flexion was 60 degrees (range 40-100 degrees). Local complications were seen in 14 of the 17 patients: 9 wound infections, 7 luxations, and 2 leg length discrepancies requiring additional surgery. In the 5 surviving patients the MSTS score at long-term follow up was 47%, the mean TESS score was 53%, the mean composite SF-36 physical and mental scores were 43.92 and 50.64 respectively. Conclusion. Reconstruction with saddle prosthesis after peri-acetabular tumour surgery has a high risk of complications, and poor long term functional outcome with limited flexion of the hip

Introduction: The senior author undertakes single stage revision hip arthroplasty for cases with no preoperative evidence of infection based on history and examination, ESR and CRP results and negative results from selective aspirations. Despite this a large proportion of intra-operative samples are positive for infection. The purpose of our study is to look at the results of intra-operative histology and microbiology samples in these cases and to assess the subsequent incidence of infection. Methods: Retrospective case study comprising of 230 single stage revision total hip arthroplasties carried out by a single surgeon over 5 year period (2003–2008). Intra-operatively tissue samples were taken from multiple sites and sent for both histology and microbiology. Microbiology results were reported at 24hrs, 48hrs, 7 days and 21 days and correlated with histology reports. Results: From a total number of 230 patients, we had 98 left and 132 right hip revision arthroplasties. There were 95 men and 135 women with a mean age of 73 years (range 40–93). Intra-operative microbiology was negative in 108 patients (46.95%), of which 3 patients’ histology samples were consistent with infection. Of the 122 microbiology positive patients (53.04%), there were 8 histology samples consistent with infection. The most frequent growths were of Coagulase negative Staphylococcus (64 cases) and Propionibacterium (18 cases). 3 cases subsequently developed deep infection. Discussion: This study highlights a significant discrepancy between intra-operative microbiology and intra-operative histology results. There is also a very high discrepancy between pre-operative assessment and intra-operative microbiological findings although the majority of cases subsequently did not show any clinical evidence of infection

Aims: Prospective multi-center study to evaluate the mid-term results of 280 uncemented femoral stem revisions using the modular MRP-Titan system. Methods: 273 patients with 280 MRP-Titan systems, follow-up for a mean time of 3 years (1 to 8 years). Harris hip score for clinical evaluation, bony defect classification according to Paprosky [163 cases (58%) with type 2B, 2C and 3]. Results: Three aseptic loosenings (1%), three septic loosenings (1%), one additional re-revision because of periprosthetic fracture. Postoperative dislocations occurred in 23 cases (8%), 17 of these (6%) were managed by closed or open reposition without changing the implant. In 6 cases (2%) the antetorsion angle of the modular prosthesis neck was altered. Harris hip score: 38 points preoperatively, 85 points at the last follow-up postoperatively. In 18 cases (6.4%) radiolucient lines were seen, but with no progression and no migration of the stems. The overall survival-rate after 8 years of follow-up was 92%. Conclusions: The modular MRP-Titan system has proven to be valuable in quite problematic cases of hip revision arthroplasty with extensive femoral defects. The system allows intraoperative adaptation of implant length and antetorsion angle to the actual situation, a feature not provided by non-modular femoral revision implants

Introduction: Total hip arthroplasty is one of the most frequently performed surgical procedures, with implants usually giving over 90% survival at 10 years. The failure rate is primarily due to aseptic loosening often associated with progressive bone stock loss. Impaction of cancellous morselized allografts with cement can be used for revision total hip arthroplasty in such cases. There is increasing interest in the use of synthetic bone graft substitutes as extenders to allograft due to the shortage and variable quality of allograft. A chemically-pure synthetic calcium phosphate (CaP) allograft extender is compared with allograft alone for acetabular and/or femoral revisions using the Impaction Grafting technique. Methods: 96 hips in 94 patients underwent revision hip arthroplasty using impaction grafting at 4 sites. Hip revision using impaction grafting was carried out using the Exeter X-Change Instrumentation system, using an Exeter Stem and/or a cemented polyethylene cup. Patients were randomized to receive allograft or CaP plus allograft in a 50:50 volume. Clinical and radiographic assessment was conducted pre-operatively and immediately post-operatively and at 6, 12 and 24 months. Clinical assessments included Harris Hip, Oxford and Charnley modified Merle d’Aubigne scores. Clinical complications were also recorded. Radiographs were assessed for the graft quality, radiolucent lines, lyses or migration, and incorporation of graft. The X-rays were also independently reviewed by an experienced author. Results: The mean age was 70.2 years (range 41–89 years) with 58 males and 36 females. A total of 40 femoral revisions and 88 acetabular revisions were conducted. There were 46 patients in the ApaPore group, 49 patients in the allograft group and 1 patient who received CaP/allograft and allograft for an acetabular and femoral revision respectively. No deep infections or adverse events due to the CaP were reported, with no significant difference in complication rates including revision and re-operations. No significant difference in acetabular migration, femoral subsidence, radiolucencies and lyses between the groups was observed. The independent review found no difference between the groups in terms of migration. The bone density was apparently greater for the ApaPore group at 12 months (p=0.001) and 24 months (p=0.012) although the significance of this is unclear. No significant difference in the clinical measures was observed between the groups. Conclusion: CaP is comparable with allograft in terms of performance and safety when used as an allograft extender for total hip revision arthroplasty using impaction grafting

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