Acetabular revisions using porous tantalum components: A retrospective study with 5-10 years follow-up

Does Using Highly Porous Tantalum in Revision Total Hip Arthroplasty Reduce the Rate of Periprosthetic Joint Infection? A Systematic Review and Meta-Analysis

Background

Studies suggest tantalum (Ta) implants may have inherent antibacterial properties. However, there is no consensus regarding the effectiveness of Ta in preventing periprosthetic joint infection (PJI) after revision total hip arthroplasty (rTHA).

Methods

We searched 5 main databases for articles reporting the rate of PJI following rTHA using Ta implants from inception to February 2022. The PJI rates of the Ta group were meta-analyzed, compared with the control group, and represented as relative risks (RRs) in forest plots.

Results

We identified 67 eligible studies (28,414 joints) for assessing the prevalence of PJI following rTHA using Ta implants. Among these studies, only 9 compared the Ta implant group with a control group. The overall PJI rate following rTHA using Ta implants was 2.9% (95% confidence interval [CI]: 2.2%-3.8%), while it was 5.7% (95% CI = 4.1%-7.8%) if only septic revisions were considered. Comparing the Ta and control groups showed a significantly lower PJI rate following all-cause rTHA with an RR = 0.80 (95% CI = 0.65-0.98, P < .05). There was a trend toward lower reinfection rates in the Ta group after rTHA in septic cases, although the difference was not statistically significant (RR = 0.75, 95% CI = 0.44-1.29, P = .30).

Conclusions

Ta implants are associated with a lower PJI rate following all-cause rTHA but not after septic causes. Despite positive results, the clinical significance of Ta still remains unclear since the PJI rate was only reduced by 20%.

Level of Evidence

IV.

Treatment of Severe Acetabular Defects With an Antiprotrusio Cage and Trabecular Metal Augments - Clinical and Radiographic Results After a Mean Follow-Up of 6.6 Years

BACKGROUND

Large acetabular bone defects present a serious challenge in revision total hip arthroplasty. The off-label use of antiprotrusio cages in combination with tantalum augments is a promising treatment option in these difficult situations.

METHODS

Between 2008 and 2013, 100 consecutive patients underwent acetabular cup revision with a cage-augment combination in Paprosky 2 and 3 defect types (including pelvic discontinuities). There were 59 patients available for follow-up. The primary endpoint was the explantation of the cage-and-augment construct. The secondary endpoint was acetabular cup revision for any reason. Also, radiographic and functional outcomes (Western Ontario and McMaster Universities Osteoarthritis Index, Harris Hip Score) were evaluated. Implant survival rates were determined using a Kaplan-Meier analysis. The significance level was set at P < .05.

RESULTS

Explantation-free survivorship of the "Cage-and-Augment" system was 91.9% after a mean follow-up of 6.2 years (range, 0 to 12.8). All 6 explantations were due to periprosthetic joint infection (PJI). The overall revision-free implant survival rate was 85.7%, including 6 additional liner revisions due to instability. In addition, 6 early PJI occurred, which were successfully treated with debridement, irrigation, and implant retention. We did observe one patient who had radiographic loosening of the construct without necessity for treatment.

CONCLUSION

The combination of an antiprotrusio cage with tantalum augments is a promising technique in treating large acetabular defects. A major risk of PJI and instability due to large bone and soft tissue defects needs special attention.

[Strategies for cup revision]

Hip arthroplasty revision management can range from simple procedures using standard implants to complex surgical interventions requiring the combined use of revision cups, metal augments, bone grafts, and antiprotrusio cages. The adequate restoration of biomechanics and function of the hip joint with reconstruction of the original center of rotation can be challenging. We present an overview of various available techniques with the associated implant and anchoring strategies and the respective clinical results depending on the acetabular defect situation.

Do Acetabular Buttress Augment Pose Risk to the Superior Gluteal Nerve? A Cadaveric Study

Background

Management of acetabular defects in total joint reconstruction can be challenging. Various algorithmic approaches have been developed, with some recommending using posterosuperior acetabular buttress augments for severe defects. The superior gluteal nerve lies in close proximity to their application, and damage to it results in deterioration of hip stability and gait mechanics. There has been investigation into the relationship of the superior gluteal nerve to various anatomic points. To our knowledge, no study exists examining the relationship between the acetabular rim and the superior gluteal nerve for the application of these particular devices.

Methods

Ten adult cadaver specimens were examined. A reproducible technique in relation to the typical placement of a buttress augment was used. From a distance of 20 millimeters (mm) lateral to the greater sciatic notch, the distance from the superior gluteal nerve to the posterosuperior acetabular rim was measured.

Results

The average distance between the posterosuperior acetabular rim and the superior gluteal nerve was found to be 52 mm, ranging from 48 mm to 60 mm.

Conclusion

With proprietary acetabular augments measuring up to 68 mm in length, the superior gluteal nerve could be at substantial risk with placement of these devices. Surgeons should take great care with dissection for and intraoperative placement of these devices, and particularly strive for optimized prosthetic hip stability to mitigate the risk of dislocation from nerve injury. To our knowledge, this study is the first of its kind and provides valuable anatomic and operative knowledge during these highly complex cases.

Constrained Liners Implanted Simultaneously at the Time of Acetabular Shell Revision with a Highly Porous Implant: Surprisingly Good Fixation at 10 Years

BACKGROUND

Many surgeons are reluctant to use a constrained liner at the time of acetabular component revision because of concerns that doing so might result in early acetabular component loosening related to high bone-implant interface stresses transmitted from the constrained liner. We hypothesized that, with appropriate initial implant stabilization using highly porous acetabular components with robust supplemental screw fixation, constrained liners could be safely used at the time of acetabular revision.

METHODS

We retrospectively identified 148 revision total hip arthroplasties (THAs) in which a constrained liner of 1 design was cemented into a newly placed highly porous acetabular component fixed with supplemental screws (mean, 5 screws). The mean age at the time of revision THA was 69 years, and 68% of the patients were female. The most common indications for revision were 2-stage reimplantation (33%), recurrent dislocation (30%), and aseptic loosening of the acetabular component (22%) or both the acetabular and femoral components (9%). The mean duration of follow-up was 7 years.

RESULTS

There were no failures at the bone-implant interface. No cases of acetabular metal shell loosening were identified on radiographic analysis. The 10-year survival rates with acetabular revision and any reoperation as the end points were 75% and 67%, respectively. Overall, 33 hips (22%) required revision or reoperation because of infection or wound complications (n = 12), dislocation or mechanical failure of the constrained liner (n = 11), periprosthetic femoral fracture (n = 4), femoral loosening (n = 3), or other reasons (n = 3). The 10-year survival rate with re-revision for instability as the end point was 88% overall, which was similar to the 85% 10-year survival rate with re-revision for instability as the end point among hips that were specifically revised because of instability during index revision THA (p = 0.9).

CONCLUSIONS

Implanting a constrained liner at the time of acetabular revision in high-risk patients resulted in no cases of aseptic metal acetabular component loosening in this large series. This finding is likely related to the fact that a highly porous acetabular component was utilized with robust supplemental screw fixation in each case. Such information is valuable as these data favor a paradigm shift when compared with some traditionally held tenets.

LEVEL OF EVIDENCE

Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.