Impaction bone grafting in hip re-revision surgery

Outcomes of a Double-Cup Construct to Treat Paprosky 3A and 3B Acetabular Defects at a Mean of 39 Months

BACKGROUND

Modular reconstruction systems based on porous tantalum (PT) prosthetic components have been increasingly used for the treatment of complex acetabular bone defects in revision total hip arthroplasty. We report a novel technique that applies a revision cup as a "super-augment" to form a "double-cup" construct for Paprosky type III defects.

METHODS

A retrospective review was conducted on revision total hip arthroplasty cases, comparing those treated with double-cup constructs (DC group, n = 48) to those treated with PT shells and augments (PT group, n = 48). All procedures were performed at the same institute between 2017 and 2022. Clinical outcome evaluation utilized the Harris Hip Score, Oxford Hip Score, and the 36-Item Short Form Survey. Preoperative and postoperative radiographic assessments measured hip center of rotation (COR) position and leg length discrepancy. Additionally, postoperative complications and implant survivorship were monitored during the follow-up period.

RESULTS

The clinical outcomes improved substantially in both groups, which showed no significant difference in the Harris Hip Score (P = .786), the Oxford Hip Score (P = .570), and the 36-Item Short Form Survey (P = .691). Compared to the PT group, the reconstruction COR was significantly closer to the anatomic COR (vertical distance: 2.630 versus 7.355 mm, P = .0034; horizontal distance: 1.881 versus -6.413 mm, P < .0001) in Paprosky 3B type defects. Additionally, postoperative leg length discrepancy was less in the DC group (-8.252 versus -1.821 mm, P = .0008). Dislocation was the main complication in the DC group, and only 1 patient received re-revision due to repeated dislocation. The cumulative survival rate of the DC group (100%; 95% confidence interval 100) was better than the PT group (83.4%; 95% confidence interval 70.5 to 98.6) when re-revisions for aseptic loosening were the endpoint (P = .046).

CONCLUSIONS

The DC is a reliable revision technique for the reconstruction of Paprosky type III bone defects. Although dislocation remains challenging, the biomechanically superior restoration achieved by this technique lowers the risk of aseptic loosening.

Personalized digital simulation‑assisted acetabular component implantation in revision hip arthroplasty

The number of artificial total hip revision arthroplasties is increasing yearly in China, and >50% of these cases have acetabular defects. Accurately locating and quantifying the bone defect is one of the current challenges of this surgery. Thus, the objective of the present study was to simulate acetabular implantation with the aid of Mimics 17.0 software (Materialise NV) in patients with loosened acetabular prosthesis, to evaluate the 'ideal acetabular center' and the 'actual acetabular center' to guide the choice of prosthesis and surgical method. From January 2017 to June 2021, the present study included 10 hips from 10 patients [seven men (seven hips) and three women (three hips)]. In all patients, the Mimics software was applied to simulate the dislocation of the femoral prosthesis and acetabular prosthesis implantation before surgery; calculate the height difference between the 'ideal acetabular center' and the 'actual acetabular center' to assess the bone defect; confirm the size of the acetabular prosthesis, abduction angle, anteversion angle and bone coverage of the acetabular cup; and measure the intraoperative bleeding and postoperative follow-up Harris score of the hip joint. After statistical analysis, the present study revealed that digital simulation assistance could improve the accuracy of hip revision acetabular prosthesis implantation, reduce postoperative shortening of the affected limb, especially for surgeons with relatively little experience in hip revision surgery, and greatly reduce the occurrence of complications such as hip dislocation because of poor postoperative prosthesis position.

Advanced quantitative 3D imaging improves the reliability of the classification of acetabular defects

INTRODUCTION

Classifying complex acetabular defects in revision total hip arthroplasty (THA) by means of conventional radiographs comes with significant limitations. Statistical shape modelling allows the virtual reconstruction of the native pelvic morphology, hereby enabling an analytic acetabular defect assessment. Our objective was to evaluate the effect of advanced imaging augmented with analytic representations of the defect on (1) intra- and inter-rater reliability, and (2) up- or downscaling of classification scores when evaluating acetabular defects in patients undergoing revision THA.

MATERIALS AND METHODS

The acetabular defects of 50 patients undergoing revision THA were evaluated by three independent, fellowship-trained orthopaedic surgeons. Defects were classified according to the acetabular defect classification (ADC) using four different imaging-based representations, namely, standard radiographs, CT imaging, a virtual three-dimensional (3D) model and a quantitative analytic representation of the defect based on a statistical shape model reconstruction. Intra- and inter-rater reliabilities were quantified using Fleiss' and Cohen's kappa scores, respectively. Up- and downscaling of classification scores were compared for each of the imaging-based representations and differences were tested.

RESULTS

Overall inter-rater agreement across all imaging-based representations for the classification was fair (κ 0.29 95% CI 0.28-0.30). Inter-rater agreement was lowest for radiographs (κ 0.21 95% CI 0.19-0.22) and increased for other representations with agreement being highest when using analytic defect models (κ 0.46 95% CI 0.43-0.48). Overall intra-rater agreement was moderate (κ 0.51 95% CI 0.42-0.60). Intra-rater agreement was lowest for radiographs (κ 0.40 95% CI 0.23-0.57), and highest for ratings including analytic defect models (κ 0.64:95% CI 0.46-0.82). Virtual 3D models with quantitative analytic defect representations upscaled acetabular defect scores in comparison to standard radiographs.

CONCLUSIONS

Using 3D CT imaging with statistical shape models doubles the intra- and inter-rater reliability and results in upscaling of acetabular defect classification when compared to standard radiographs. This method of evaluating defects will aid in planning surgical reconstruction and stimulate the development of new classification systems based on advanced imaging techniques.

Mid- to Long-term Follow-up of Severe Acetabular Bone Defect after Revision Total Hip Arthroplasty Using Impaction Bone Grafting and Metal Mesh

OBJECTIVE

In revision total hip arthroplasty (THA), reconstruction of severe acetabular bone defect continues to be problematic for orthopedic surgeons. This study reports the mid- to long-term survivorship, radiological outcomes, and complications of impaction bone grafting (IBG) and metal mesh with a cemented acetabular component in the reconstruction of severe acetabular bone defects in revision THA.

METHODS

This retrospective consecutive study included 26 patients (29 hips: type II B, four; type II C, three; type III A, 10; and type III B, 12) who underwent revision THA, which was performed using IBG and metal mesh, between 2007 and 2014 in our institution. All patients were followed up regularly for clinical and radiographical assessments. Migration and loosening of prosthesis graft integration and complications were observed and analyzed. Survival analysis was performed using a Kaplan-Meier survival analysis.

RESULTS

At the time of revision, 75.9% of the hips (22 hips) were classified as type III bone defects. The average follow-up period was 9.4 ± 2.8 (range, 2.4-14.0) years. Of the 29 hips, four hips (13.8%) were assessed as clinical failures; at the last follow-up, two had undergone re-revision THA, and two had not been scheduled for re-revision THA despite radiological failure of the acetabular component. Among them, three clinical failures (10.3%) were due to aseptic loosening, and one (3.4%) was due to infection. Radiographic evaluation showed bone graft integration in all hips during the follow-up. The Kaplan-Meier survivorship analysis revealed an acetabular reconstruction survival rate of 86.5% (95% confidence interval, 61.4%-95.7%) at 10 years.

CONCLUSION

IBG and metal mesh with a cemented acetabular component for revision THA is an effective technique for treating severe acetabular bone defects, with effective mid- to long-term outcomes due to the solid reconstruction of the acetabular bone defect and restoration of the hip rotation center.

Palmitic acid coating of allogeneic cancellous bone for local antibiotic treatment: A porcine impaction bone grafting model

Introduction

The worldwide rising number of joint replacements results in increasing revision surgery including a relevant portion of septic loosening accompanied by bone deficiencies. Loading of allogeneic bone with antibiotics provides high local antibiotic concentrations and might eradicate bacteria which appear resistant to systemic antibiotic application. Hydrophobic palmitic acid was shown to be a suitable carrier for antibiotics and prevents biofilm.

Methods

Cancellous bone derived from 6 to 7 months old piglets was used for a standardized in vitro impaction bone grafting model according to previous studies. The specimens were either thermodisinfected or remained native and palmitic acid with one third and two third partial weight were added and compared with control. Shear force at the interface prosthesis to cement and between cement and bone was measured. The relative micromovements were measured with 6 inductive sensors with a resolution of 0.1 μm at three different measuring heights up to a maximum movement of 150 μm between cement and bone. Taking into account the corresponding applied torque the measured values were normalized in μm/Nm. Statistical analysis was done with SPSS Statistics® Version 26.0 IBM.

Results

Smallest movement was measured for thermodisinfected cancellous bone and a not significant decrease of shear force resistance with addition of palmitic acid was found since supplementing native cancellous bone reduced shear force resistance significantly depending on the weight percentage of palmitic acid.

Conclusion

Supplementation of porcine cancellous bone with palmitic acid did not significantly reduce shear force resistance of thermodisinfected bone since adding palmitic acid to native bone decreased it significantly depending on the volume added. Palmitic acid seems to be a suitable coating for allogeneic cancellous bone to deliver high local antibiotic concentrations and thermodisinfected cancellous bone might be able to store larger volumes of palmitic acid than native bone without relevant influence on shear force resistance.

Impaction bone grafting for segmental acetabular defects: a biomechanical study

INTRODUCTION

Implant loosening is the most common indication for revision after total hip arthroplasty and is associated with progressive bone destruction. Contained defects can be treated with impaction bone grafting (IBG). Segmental defects are successfully restored with metal augmentation. Considering the increasing number of hip arthroplasty cases in young patients, it would appear sensible to reconstruct the bone stock for future revisions by biological bone defect reduction. The data on the treatment of segmental defects with IBG without additional stabilization are lacking.

MATERIALS AND METHODS

Paprosky type IIB defects were milled into 15 porcine hemipelves with segmental defect angles of 40°, 80° and 120°. Contained defects without segmental defects (Paprosky type I) and acetabula without defects served as controls. After IBG, a cemented polyethylene cup (PE) was implanted in each case. Cup migration, rotational stiffness and maximum rupture torque were determined under physiological loading conditions after 2500 cycles.

RESULTS

Compared with the control without defects, IBG cups showed an asymptotic migration of 0.26 mm ± 0.11 mm on average. This seating was not dependent on the size of the defect. The maximum rupture moment was also not dependent on the defect size for cups after IBG. In contrast, the torsional stiffness of cups with an 120° segmental defect angle was significantly lower than in the control group without defects. All other defects did not differ in torsional stiffness from the control without defects.

CONCLUSIONS

IBG did not show inferior biomechanical properties in segmental type IIB defect angles up to 80°, compared to cups without defects.

Impaction Bone Grafting with Low Dose Irradiated Freeze-Dried Allograft Bone for Acetabular Reconstruction

OBJECTIVE

Reconstruction of acetabular defects has been extremely challenging in both primary and revision total hip arthroplasty (THA). Impaction bone grafting (IBG) can restore the acetabulum bone mass and anatomically reconstruct the acetabulum. Our study aimed to report the short and medium-term clinical and radiographic outcomes of IBG for acetabular reconstruction in the cemented THA in the Chinese population.

METHODS

This was a single-center retrospective review enrolling 57 patients between May 2013 and July 2019. The patients with acetabular defects were treated with IBG, using low dose irradiated freeze-dried allograft bone with or without autograft bone, in the cemented THA performed by one senior surgeon. Harris hip score (HHS), standard pelvis anterior-posterior radiograph and lateral hip radiograph were obtained before operation and at 1 week, 3 months, 12 months, and yearly. Graft osteointegration was evaluated by Oswestry's criteria, and complication was documented at the last follow-up. Independent sample ANOVA test and Pearson chi-square tests are used for statistical analysis.

RESULTS

There were 61 hips in 57 patients. The average follow-up time was 35.59 months (5-77 months). According to AAOS classification, a total of 18 hips were identified as segmental bone deficiency (type I), with 21 and 22 hips for cavitary bone deficiency (type II) and the combined bone deficiency (type III), respectively. The average HHS was improved from 44.49 (range: 32-58) preoperatively to 86.98 (range: 78-93) postoperatively. Graft osteointegration was satisfactory (Oswestry score ≥2) in all patients. No dislocation occurred in the 57 patients (61 hips) during follow-up. Although one cup migrated, no revision, re-revision, radiographic loosening, graft bone lysis, or postoperative complications were detected at the final follow-up.

CONCLUSIONS

IBG with low-dose irradiated freeze-dried allograft bone in acetabular bone defect reconstruction is a reliable technique for restoring acetabular bone defects in THA.

Impaction Grafting Is Sufficient to Address Acetabular Deficiency During Total Hip Arthroplasty of Most Dysplastic Hips With Over 30% Bone Defect

BACKGROUND

Addressing acetabular deficiency during arthroplasty of dysplastic hips is challenging. We assessed outcomes of a protocol for choosing either impaction or structural graft for this purpose.

METHODS

This retrospective study included 59 patients (71 hips) with a dysplastic hip and over 30% uncoverage that underwent cementless total hip arthroplasty. Morselized impaction grafting was performed for hips where initial stability of the acetabular cup was achieved. In others, a shelf graft was inserted before implantation of the acetabular cup. Outcomes were assessed at a minimum follow-up of 4 years.

RESULTS

Fifty-seven (80.3%) hips underwent impaction grafting and 14 (19.7%) received a structural graft. Mean age at surgery was 48.1 ± 13.5 (18-68) years for impaction and 48.6 ± 14 (24-70) years for shelf grafts. Mean increase in Harris Hip Score was 51.5 ± 9.3 and 50 ± 11.2 for the impaction and structural groups, respectively, at a mean follow-up of 92 (49-136) months (P = .6). Heterotopic ossification occurred in 16 patients in the impaction group vs none in the structural group (P = .004). Radiologically, mean percentages of cup coverage provided by the graft were 47.8 ± 10.9% and 48.9 ± 13.3% in the impaction and structural groups, respectively (P = .75). All but one of shelf grafts united to host bone and all impaction grafts incorporated. There was one case of cup loosening in the structural graft group.

CONCLUSION

Most dysplastic acetabula with over 30% defect can be addressed using a cementless cup and impaction grafting, with good results in the midterm. In about 20% of cases, initial press-fit is not attainable and structural support-like shelf graft becomes necessary.

LEVEL OF EVIDENCE

IV.

Impaction Bone Grafting Combined with Titanium Mesh for Acetabular Bone Defects Reconstruction in Total Hip Arthroplasty Revision: A Retrospective and Mini-Review Study

Objective

To investigate the application of impaction bone grafting (IBG) combined with Ti‐alloy mesh for acetabular bone defect reconstruction in total hip arthroplasty (THA) revision and follow up the clinical outcomes and imaging findings.

Methods

The clinical and imaging data of patients who were admitted to our hospital from January 2000 to December 2020 and underwent acetabular bone defects reconstruction using IBG combined with titanium mesh were retrospectively analyzed. Preoperative and post‐revision Oxford and Harris scores, and post‐revision complications were evaluated. Radiographs were used to determine center of rotation (COR) of the hip joint, transparency line, bone graft fusion, and bone mineral density (BMD) around the hip joint.

Results

Significant improvement was observed in both Oxford and Harris scores (P < 0.05). The radiographs taken at the last follow‐up examination showed no significant differences in the acetabulum COR, offsets, inclination angle, mean ratio of vertical value, and BMD analysis between the post‐revision side and contralateral side (P > 0.05). The follow‐up data showed restoration of the mesh implant and graft bone fusion.

Conclusions

The application of IBG combined with titanium‐alloy mesh in revision THA patients with acetabular defects was found to provide satisfactory outcomes. However, large‐scale studies are still needed to further elucidate the long‐term outcomes.