High failure rate with the GAP II ring and impacted allograft bone in severe acetabular defects

Evaluation results of using GAP II acetabular cage for acetabulum in revision total hip arthroplasty

Acetabular revision arthroplasty with major bone loss is one of the most difficult operations in hip arthroplasty, The graft augmentation prosthesis (GAP) has been designed particularly as an implant for revision acetabular reconstruction. We evaluated the use of GAP II acetabular cage in revision of acetabulum in total hip arthroplasty. From 2009 to 2014, we performed revision total hip arthroplasty in patients with acetabular defects by cage (GAP II) in patients referred to Milad and Erfan Hospitals, Tehran, Iran. We included all patients in class 3a and 3b of Paprosky bone loss classification and type III bone loss according to the system of the American Academy of Orthopedic Surgeons. We used SPSS software Ver 19 and descriptive tests, Chi square and independent t-test were used for analysis. There were 221 men (71.99%) and 86 women (28.01%) with an average age of 51.3 ± 21.7 years (range, 35-86 years). The Modified Harris Hip Score (MHHS) improved significantly at the last follow-up compared with the preoperative MHHS (P < .001). The mean MHHS was 40 (range, 29-44) preoperatively and 92 (range, 86-95) at the last follow-up. There were no major intraoperative complications during acetabular reconstruction. Our findings showed that using GAP II acetabular cage in the restoration of acetabulum in hip revision surgery is significantly desirable.

Lyophilized Human Bone Allograft as an Antibiotic Carrier: An In Vitro and In Vivo Study

Background: Antibiotics delivered from implanted bone substitute materials (BSM) can potentially be used to prevent acute infections and biofilm formation, providing high concentrations of antibiotics at the surgical site without systemic toxicity. In addition, BSM should allow osteoconductivity supporting bone healing without further surgery. Promising results have been achieved using lyophilized bone allografts mixed with antibiotics. Methods: In this study specially prepared human bone allografts were evaluated as an antibiotic carrier in vitro and in vivo. The efficacy of different antibiotic-impregnated bone allografts was measured by drug release tests in vitro and in vivo and bacterial susceptibility tests using four bacterial species usually responsible for implant-associated infections. Results: The loading procedures of allograft bone substitutes with antibiotics were successful. Some of the antibiotic concentrations exceeded the MIC90 for up to 7 days in vitro and for up to 72 h in vivo. The susceptibility tests showed that S. epidermidis ATCC 12228 was the most susceptible bacterial species in comparison to the other strains tested for all antibiotic substances. Vancomycin and rifampicin showed the best results against standard and patient-isolated strains in vitro. In vivo, new bone formation was comparable in all study groups including the control group without antibiotic loading. Conclusions: Human bone allografts showed the capacity to act as customized loaded antibiotic carriers to prevent acute infections and should be considered in the management of bone infections in combination with systemic antimicrobial therapy.

Pelvic discontinuity: a challenge to overcome

Pelvic discontinuity (PD) has been a considerable challenge for the hip revision arthroplasty surgeon. However, not all PDs are the same. Some occur during primary cup insertion, resembling a fresh periprosthetic fracture that separates the superior and inferior portions of the pelvis, while others are chronic as a result of gradual acetabular bone loss due to osteolysis and/or acetabular implant loosening.

In the past, ORIF, various types of cages, bone grafts and bone cement were utilized with little success. Today, the biomechanics and biology of PD as well as new diagnostic tools and especially a variety of new implants and techniques are available to hip revision surgeons. Ultraporous cups and augments, cup-cage constructs and custom triflange components have revolutionized the treatment of PD when used in various combinations with ORIF and bone grafts. For chronic PD the cup-cage construct is the most popular method of reconstruction with good medium-term results.

Dislocation continues to be the leading cause of failure in all situations, followed by infection. Ultimately, surgeons today have a big enough armamentarium to select the best treatment approach. Case individualization, personal experience and improvisation are the best assets to drive treatment decisions and strategies.

Cite this article: EFORT Open Rev 2021;6:459-471. DOI: 10.1302/2058-5241.6.210022

Outcome and EBRA migration analysis of a reconstruction cage in acetabular revision arthroplasty: a clinical and radiological study

PURPOSE

Restoration cages and bone allografts have been proposed to manage severe acetabular bone defects. We aimed to investigate the migration behaviour of a restoration cup and impacted allograft bone in severe acetabular defects with Einzel-Bild-Röntgen-Analyse (EBRA).

METHODS

Applying a retrospective study design, 64 cases treated between 2009 and 2016 were reviewed. We determined the preoperative Charlson Comorbidity Index (CCI), pre- to postoperative WOMAC score, blood loss and functional outcome. From preoperative x rays, the acetabular deficiencies were classified according to Paprosky. Cup migration analyses were performed with EBRA.

RESULTS

Mean age at surgery was 73 (range: 38-93) years. According to the classification by Paprosky et al., 50% (n = 32) of our patients showed a type III B and 28.1% (n = 18) a type III A defect. Radiological follow-up for migration analysis was 35 (range: 4-95) months. Migration analysis showed a mean cup migration of 0.7 mm (range: 5.7-9.6) medial and 1.8 mm (range: 1.7-12.6) cranial.

CONCLUSION

In conclusion, acetabular restoration cages in combination with bone impaction grafting showed a low revision rate at a mean follow-up of 35 months. Mean cup migration revealed low rates after 2 years and suggested a stable postoperative implant position.

Mid-term Follow-up of the Direct Anterior Approach in Acetabular Revision Hip Arthroplasty Using a Reconstruction Cage With Impaction Grafting

BACKGROUND

Severe acetabular bone loss is often treated with reconstruction cages and impaction grafting using allograft bone. Accurate implant positioning is crucial for successful clinical and radiological outcomes. The direct anterior approach (DAA) is a standard approach for primary total hip arthroplasty (THA) that is being used more frequently for revision THA. The aim of this study was to report midterm clinical and radiological outcomes of acetabular revision arthroplasty using the DAA to address large acetabular defects by using a reconstruction cage and impaction grafting.

METHODS

Acetabular cup revisions were performed in 64 patients (64 hips) with severe acetabular bone loss. All patients received reconstruction cages with impaction grafting via the DAA. The stem was also revised in 22 patients. Complications, radiological, and functional outcomes were assessed.

RESULTS

Six of the 64 patients were revised at a mean follow-up of 27.6 months (range, 11-84 months), two each for implant failure, infection, and recurrent dislocation. One hip showed the radiological failure of the implant, but the patient was asymptomatic and was not revised. The median Western Ontario McMasters Osteoarthritis Score (WOMAC) for the cohort overall improved significantly (P < .01) by the latest follow-up compared with preoperative scores.

CONCLUSION

Good midterm outcomes can be obtained with the DAA for acetabular cup revisions done to address severe acetabular bone loss by using reconstruction cages and impaction grafting. The number of complications was within the expected range for this type of revision procedure at midterm follow-up, and dislocation rates were low.

Reliability of acellular decalcified and decalcified teeth as bone graft material: an experimental and pathological study in rats

OBJECTIVE

The present study aimed to investigate the reliability of acellular decalcified teeth in the development of bone scaffolds and in bone regeneration in rats.

METHODS

(1) Forty-eight human teeth were divided into two groups in vitro: twenty-four were decalcified, while the remaining twenty-four were decalcified and decellularized, following which a conventional scanning-electron microscope analysis was performed. (2) In another experiment, six male SD rats aged 10-12 weeks were selected, then decalcified and acellular decalcified teeth were embedded subcutaneously in the abdomen of the rats. After 4 weeks, the rats were sacrificed for H-E staining and immunohistochemical staining to observe the inflammatory reaction around the two materials. (3) In the ectopic osteogenesis experiment, bone defects were simulated in bilateral craniotectal areas of 12 male SD rats (age 10-12 weeks), following which acellular decalcified teeth were implanted in the right bone defect. The non-implanted left side was used as blank control. At week 4 and week 8, 6 rats were randomly selected for execution, complete specimens were obtained, and micro-CT scan was performed to compare the bone mass from gross morphology. H-E staining was performed at 4 and 8 weeks to observe the surrounding inflammatory response and immunohistochemistry was performed at 8 weeks to observe the degree of new bone formation. SPSS 23.0 software package was used for statistical processing.

RESULTS

(1) Under scanning electron microscope, cells in the teeth subjected to acellular decalcification completely disappeared, leaving only inorganic scaffolds. (2) After 4 weeks, the amount of inflammatory reaction in the tissues surrounding acellular decalcified teeth was significantly lower than that in the tissues surrounding decalcified teeth. (3) After four and eight weeks, the amount of bone formation in the bone defects was significantly higher in rats implanted with acellular decalcified teeth than in those in the blank control group (P<0.05). After four and eight weeks, hematoxylin-eosin staining revealed that the degree of inflammatory response was similar around acellular decalcified teeth and blank controls. Immunohistochemistry indicated that the osteocalcin levels were significantly higher around acellular decalcified teeth than that around blank controls.

CONCLUSION

Acellular decalcified teeth show significantly decreased inflammatory reaction, better biocompatibility, better osteogenic potential, and better plasticity than decalcified teeth alone.

Reconstruction for pelvic discontinuity and massive acetabular defects

OBJECTIVE

The acetabular reconstruction with massive acetabular defects and pelvic discontinuity is a complex surgery with important difficulties for the orthopaedic surgeon. The objective of this study is to show the short and midterm results of the acetabular revision with the Cup-Cage construct in a consecutive serie of cases.

MATERIAL AND METHODS

Retrospectively we reviewed 22 consecutive patients with massive acetabular defects (8 Paprosky IIIa and 9 IIIB); 5 pelvic discontinuities; 2 pelvic fractures during the implantation of primary artroplasty, and one pelvic pseudoarthrosis. All were reoperated with a trabecular metal acetabular component and a Cup-Cage. We did clinical and radiological follow-up to detect machanical failures and loosening of the implant.

RESULTS

With a middle follow-up of 45.06 months (12-73 months) we did not see any radiographic failure of the implant (component migration, osteolysis neither rupture of the implant or screws). The complications (13,63%) included one recurrent luxation, one infection and one recurrent subluxation. The Merle d'Aubigné-Postel score improved from 6.91 to 14.36 and the punctuation in the range of motion from 2.91 to 4.36 on average of the values preoperatively and postoperatively respectively and improvement in Harris Hip Score 30 (16-55) to 72 (40-90) in the latest follow up.

CONCLUSION

The acetabular reconstruction with the Cup-Cage system is a valid alternative for the reconstruction of massive acetabular defects (Paprosky type IIIA and IIIB) and pelvic discontinuities offering good results at short and midterm follow-up.

Acetabular reinforcement rings associated with allograft for severe acetabular defects

Acetabular revisions with severe bone defects can be challenging procedures. Several grading systems have been set into place to help the surgeon adequately gauge the degree of bone loss within the acetabulum. Internationally innovative research in orthopedics and bio-engineering has helped with progression of successful techniques and rings to re-establish the normal anatomy of the hip. The purpose of this review is to evaluate the outcomes of the different acetabular reinforcement rings in the setting of severe acetabular defects. A successive report of relevant data from the literature of multiple techniques will be provided. The procedures include the cup-cage, the Müller ring, the Ganz Ring, the Kerboull acetabular reinforcement device (KARD), the graft augmentation prosthesis (GAP) ring, and the Burch-Schneider ring. The main focus of this overview is rings only; other devices such as trabecular augments, custom-made cages, or oblong cups are not discussed. Furthermore, a special emphasis on the surgical technique of the KARD is also given. Procedures using these rings are usually associated with bone grafts either bulk or morselized. When considering the available data on these various rings used for reconstruction of the severely damaged acetabulum, the cup-cage, the KARD, and the Burch-Schneider ring appear to be reliable options for more successful long-term outcomes.

Revision total hip arthroplasty using the Kerboull acetabular reinforcement device for Paprosky type III defects involving the inferior margin of the acetabulum: a minimum five-year follow-up study

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.

Mid-Term Results of Graft Augmentation Prosthesis II Cage and Impacted Allograft Bone in Revision Hip Arthroplasty

BACKGROUND

Several techniques have been described for management of severe acetabular bone defects during revision hip surgery including reconstructive cages. The purpose of this study is to analyze the survival and the mid-term clinical and radiological outcome using the Graft Augmentation Prosthesis (GAP II cage) (Stryker Orthopaedics, Mahwah, NJ) in addition to impaction grafting for acetabular defects in revision hip surgery.

METHODS

This is a retrospective review of all patients who underwent acetabular revision hip replacement using GAP II cage and impaction bone grafting between 2009 and 2013 at our institution. Twenty-six patients were included with a mean age of 71 years (49-91). According to Paprosky classification, 2 patients had type IIB defect, 4 had type IIC, and 12 had type IIIA, while 8 suffered from type IIIB defect. The clinical outcome was assessed using Oxford Hip Score. Plain radiographs were used to assess preoperative bone loss, postoperative implant migration, and the incorporation of the bone graft to host bone.

RESULTS

The average Oxford Hip Score improved from 11.3 (2-22) preoperatively to 32.2 (20-48) postoperatively. The revision free survivorship of this construct was 100% at mean follow-up of 49 months (30-78). Three hips had radiological failure of the implant with no clinical consequences.

CONCLUSION

The use of GAP II cage with impaction bone grafting to reconstruct severe acetabular defects had encouraging mid-term results with low failure rate. Graft incorporation with restoration of bone stock may be beneficial should further revision surgery be needed.

A 2- to 16-Year Clinical Follow-Up of Revision Total Hip Arthroplasty Using a New Acetabular Implant Combined With Impacted Bone Allografts and a Cemented Cup

BACKGROUND

Treatment of acetabular bone loss with impaction bone grafting (IBG) at revision total hip arthroplasty is highly dependent on mechanical stability and graft compression for clinical success. Here, we describe a new technique to further compress and stabilize the acetabular graft bed with a thin, perforated titanium shell.

METHODS

We retrospectively analyzed 170 cases of acetabular revision arthroplasty 7 years (standard deviation 2.8) after IBG combined with a graft-compressing titanium shell implant. The patients were reviewed by clinical score and radiography. Three patients were lost to follow-up. The medical journals of the 33 deceased cases were reviewed for any reoperation. Of the 170 cases, 74 had a cavitary acetabular bone defect, 93 had combined segmental and cavitary bone defects, and 3 had a pelvic dissociation. Bone graft incorporation was assessed and correction of the hip center of rotation was calculated.

RESULTS

Five cases (3%) were reoperated for mechanical loosening. One more was assessed as loose but asymptomatic and was not planned for revision. There were 3 reoperations for recurrent dislocation, 2 for deep infection and 1 for technical error. Reoperation for any reason, as the end point of survivorship, showed a survival rate of 92% after 10 years. Hip score according to Merle, d'Aubigne, and Postel increased from 10.8 (preoperatively) to 16.4 at follow-up. The clinical and radiological results were excellent.

CONCLUSION

IBG combined with the compressing shell results in excellent results for this challenging condition.

Determination of structural femoral head allograft viability and integrity with a novel diagnostic tool: SPECT/CT. A preliminary study

OBJECTIVE

To evaluate the viability and integrity of fresh frozen bulk femoral head allografts obtained from the institutional bone bank that were used to reconstruct severe acetabular defects and to validate the SPECT/CT method which gives both anatomical and functional data for this purpose.

METHODS

We retrospectively reviewed 9 patients (6 female, 3 male; mean age 63.6 years). Preoperative and postoperative leg lengths, existence of the Trendelenburg sign, range of motion of the hip, visual analogue score (VAS), Harris Hip Score (HHS) and any complication were assesed at each follow-up. Radiographically, position of the cup, signs of loosening or migration, and union of the graft were all determined. At the latest follow-up, patients were evaluated with hybrid SPECT/CT.

RESULTS

The average duration of follow-up was 38.1 months (24-50 months). The overall mean HHS and VAS scores were significantly improved (p<0.05). When hybrid SPECT/CT results were evaluated, the vascular phase of scintigraphy showed hyperaemia of the graft and the bone phase of scintigraphy showed normal or increased radiotracer uptake in the graft site in 7 patients. SPECT/CT images were used to determine the exact localisation of osteoblastic activity. 1 patient with minor resorption of the graft without clinical symptoms revealed mild osteoblastic activity. The patient who had no activity in the graft site was rerevised because of infection.

CONCLUSIONS

Institutional bank allografts are still excellent options for treating large acetabular defects in revision total hip arthroplasty where trabecular metals are not available or in common use. The Hybrid SPECT/CT method is a reliable, noninvasive method for evaluating both the integrity and viability of a bulk graft in 3-D.

Lyophilized allogeneic bone tissue as an antibiotic carrier

The rising number of primary joint replacements worldwide causes an increase of revision surgery of endoprostheses due bacterial infection. Revision surgery using non-cemented implants seems beneficial for the long-term outcome and the use of antibiotic-impregnated bone grafts might control the infection and give a good support for the implant. In this study we evaluated the release of antibiotics from fresh-frozen and lyophilized allogeneic bone grafts. Lyophilized bone chips and fresh frozen bone chips were mixed with gentamicin sulphate, gentamicin palmitate, vancomycin, calcium carbonate/calcium sulphate impregnated with gentamicin sulphate, and calcium carbonate/calcium sulphate bone substitute material impregnated with vancomycin. The efficacy of each preparation was measured by drug release tests and bacterial susceptibility using B. subtilis, S. aureus and methicillin-resistant Staphylococcus aureus. The release of gentamicin from lyophilized bone was similar to the release rate from fresh frozen bone during all the experimental time. That fact might be related to the similar porosity and microstructure of the bone chips. The release of gentamicin from lyophilized and fresh frozen bone was high in the first and second day, decreasing and keeping a low rate until the end of the second week. Depending on the surgical strategy either polymethylmethacrylate or allogeneic bone are able to deliver sufficient concentrations of gentamicin to achieve bacterial inhibition within two weeks after surgery. In case of uncemented revision of joint replacements allogeneic bone is able to deliver therapeutic doses of gentamicin and peak levels immediately after implantation during a fortnight. The use of lyophilized and fresh frozen bone allografts as antibiotic carriers is recommended for prophylaxis of bone infection.

Role of Cages in Revision Arthroplasty of the Acetabulum

➤ The outcome of acetabular revision is heavily influenced by the degree of associated bone loss.➤ Uncemented hemispherical acetabular components can be used in the majority of acetabular revisions, although occasionally the degree of bone loss precludes the stability of the hemispherical component at the correct anatomic level or there is minimal bleeding host bone left for biologic fixation.➤ Massive acetabular bone loss resulting in the need for bone grafts or highly porous augments involving more than half of the acetabulum is one of the main indications for the use of cages.➤ The cup-cage reconstruction is based on bone-grafting the deficient acetabulum and securing a hemispherical, highly porous metal component with multiple screws to bridge the discontinuity and off-loading the hemispherical component with a titanium cage spanning from ischium to ilium.➤ In addition to managing pelvic discontinuities, the cup-cage construct can also be used in hips without discontinuity as the hemispherical, highly porous metal component is used to restore bone stock.➤ In situations in which there is not enough bleeding host bone to secure a hemispherical component, a highly porous metal augment can be used to address the osseous deficiency. The augment is also protected with a cage to assist bone ingrowth.

The use of morselized allografts without impaction and cemented cage support in acetabular revision surgery: a 4- to 9-year follow-up

Background

Acetabular revision arthroplasty with major bone loss is one of the most difficult operations in orthopedic surgery. The goal of the study was to evaluate midterm clinical results of the use of morselized allografts with cemented cage support in revision total hip replacement.

Methods

We identified 28 patients (29 hips) at an average follow-up of 73 months. Harris Hip Scores (HHS) were assessed before and after surgery. Pre- and postoperative radiographs were evaluated for restoration of the center of rotation, component migration, and graft incorporation.

Results and discussion

At follow-up, the mean HHS improved from 34 (range, 20–45) to 80 (range, 71–98) points. None of the components had been re-revised. On average, the revised hip center of rotation was improved significantly. Incorporation of the graft was complete in 23 hips. The midterm result of cage reconstruction with morselized bone allograft is relatively better than other studies using a similar cage construction. We believe we have three special modifications of this reconstruction technique that are beneficial for bone incorporation.

Conclusions

These data confirm that acetabular reconstruction using morselized allografts and cemented acetabular cages is effective in the midterm as a treatment for acetabular loosening with massive bone deficiency.

Options for managing severe acetabular bone loss in revision hip arthroplasty. A systematic review

Revision hip arthroplasty in the presence of severe acetabular bone loss is challenging and requires a solid understanding of current techniques. A literature search of multiple databases applying specific criteria revealed a total of 50 articles of level IV scientific evidence comprising 2415 patients (2480 hips) managed with reinforcement devices (roof-reinforcement rings and anti-protrusio cages), custom-made triflanged acetabular components (CTACs), jumbo cups and tantalum metal (TM) systems. Overall, patients had improved postoperative hip scores for each technique. The use of reinforcement devices resulted in a mean revision rate of 8.2% and a mean complication rate of 29.21%. CTACs were associated with a revision rate of 15.9% and had a complication rate of 24.5%. Jumbo cups were revised in 8.8% of patients and had a complication rate of 18.4%. TM systems had an overall revision rate of 8.5% with complications seen in 18.5% of patients. CTACs had considerably higher revision rates compared to the other techniques. Jumbo cups and TM systems had lower complication rates compared to the use of reinforcement devices and CTACs. The most frequently occurring complications seen throughout the series were aseptic loosening, dislocation and infection.

The challenge of pelvic discontinuity

The use of ilioischial cage reconstruction for pelvic discontinuity has been replaced by the Trabecular Metal (Zimmer, Warsaw, Indiana) cup-cage technique in our institution, due to the unsatisfactory outcome of using a cage alone in this situation. We report the outcome of 26 pelvic discontinuities in 24 patients (20 women and four men, mean age 65 years (44 to 84)) treated by the cup-cage technique at a mean follow-up of 82 months (12 to 113) and compared them with a series of 19 pelvic discontinuities in 19 patients (18 women and one man, mean age 70 years (42 to 86)) treated with a cage at a mean follow-up of 69 months (1 to 170). The clinical and radiological outcomes as well as the survivorship of the groups were compared. In all, four of the cup-cage group (15%) and 13 (68%) of the cage group failed due to septic or aseptic loosening. The seven-year survivorship was 87.2% (95% confidence interval (CI) 71 to 103) for the cup-cage group and 49.9% (95% CI 15 to 84) for the cage-alone group (p = 0.009). There were four major complications in the cup-cage group and nine in the cage group. Radiological union of the discontinuity was found in all successful cases in the cup-cage group and three of the successful cage cases. Three hips in the cup-cage group developed early radiological migration of the components, which stabilised with a successful outcome.

Cup-cage reconstruction is a reliable technique for treating pelvic discontinuity in mid-term follow-up and is preferred to ilioischial cage reconstruction. If the continuity of the bone graft at the discontinuity site is not disrupted, early migration of the components does not necessarily result in failure.

Cite this article: Bone Joint J 2014;96-B:195–200.