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Metaphyseal cones are frequently used in revision total knee arthroplasties (TKAs). However, during subsequent aseptic re-revisions, removing a well-fixed cone can be difficult. One innovative option is to retain the well-fixed cone and cement a new, stemmed revision component through the retained cone, yet minimal data exist on this technique. We describe a technique for retaining a well-fixed cone during re-revision TKA and report outcomes in 6 patients with 6 well-fixed metaphyseal cones. At a mean of 4 years follow-up, no retained cones with a new femoral or tibial component with stems were revised and there was no radiographic evidence of aseptic loosening. These early data suggest that retaining a well-fixed cone can be safe in re-revision TKA to minimize morbidity associated with cone removal. Level of evidence: IV (retrospective study).

Objective: To assess the impact of neighborhood-level socioeconomic status factors (area deprivation index [ADI] and rural classification) and their interaction with individual-level socioeconomic status (education-level) on long-term outcomes following total joint arthroplasty (TJA) surgery. Patients and Methods: This was a cohort study of 46,828 TJA surgeries performed on patients at a tertiary care hospital between January 1, 2000 and December 31, 2019. Cox proportional hazards models were used to examine the association between ADI and rurality and their interaction with individual-level education on the risk of periprosthetic joint infections, revision surgery, and mortality. Results: At the time of surgery, 2589 (6%) patients lived in the most deprived neighborhoods (ADI quintile >80%) and 10,728 (23%) lived in small isolated rural towns. Patients from the most deprived neighborhoods were more likely to experience revision surgery (hazard ratio, [HR], 1.39; 95% CI, 1.10-1.76) and mortality (HR, 1.24; 95% CI, 1.09-1.42). Patients from small rural towns were also more likely to undergo revision surgery (HR, 1.14; 95% CI, 1.01-1.28). The mortality risk was 13%, 18%, and 24% higher for patients in the 3 highest ADI quintiles than those from the lowest quintile. Education gradient was more notable in the least deprived neighborhoods than in the most deprived neighborhoods. Conclusion: Neighborhood disadvantage and rurality are negatively associated with the risk of revision surgery and both independently and in interaction with individual-level education with the risk of mortality. There is a need for population-level health interventions to mitigate area-based socioeconomic disadvantages in TJA.

Two-stage revision total knee arthroplasty remains the gold standard for management of chronic periprosthetic joint infection in North America. Static cement antibiotic spacers used after knee resection to deliver high-dose antibiotics lack primary stability, potentially leading to spacer migration or dislocation, additional bone loss, extensor mechanism erosion, and even knee subluxation or frank dislocation. A custom brace or cast is often required to augment knee stability, which is time-consuming, costly, and prevents monitoring or wound care of the soft tissues. An external fixator arthrodesis antibiotic spacer can provide primary stability without a brace or cast, allowing for soft-tissue monitoring and care, and minimizes potential spacer complications. We present the technique for implanting and removing this specific external fixator arthrodesis antibiotic spacer. Keywords: Total knee arthroplasty, Infection, Periprosthetic joint infection, Antibiotic spacer, Static spacer

Background: Infection remains a leading cause of failure of hip and knee replacements. Infection burden is the ratio of implants revised for infection to the total number of arthroplasties in a specific period, measuring the steady state of infection in a registry. We hypothesized infection burden would be similar among arthroplasty registries. Methods: We evaluated publicly reported data from 6 arthroplasty registries (Australian Orthopaedic Association National Joint Replacement Registry [AOANJRR], New Zealand Joint Registry, Swedish Hip Arthroplasty Register, Swedish Knee Arthroplasty Register, National Joint Registry of England, Wales, Northern Ireland, and the Isle of Man, and the American Joint Replacement Registry) for revisions performed with an infection diagnosis over the last 6 years. Results: The 2015 hip infection burden varied between registries from 0.76% (AOANJRR) to 1.24% (Swedish Hip Arthroplasty Register), and the unweighted overall average for hip infection burden was 0.97%. In 2012, 2013, and 2014, average hip infection burden held steady at 0.87%, 0.93%, and 0.94%, respectively, higher than the preceding 2 years. The 2015 knee infection burden varied from 0.88% (AOANJRR) to 1.28% (Swedish Knee Arthroplasty Register), and the unweighted average was 1.03%. In 2012, 2013, and 2014, knee infection burden was 1.04%, 1.11%, and 1.02%, respectively. These numbers were also higher than the preceding 2 years. Conclusions: Infection burden may be one measure of the overall success in registry populations as well as monitoring the steady state of infection worldwide. Despite global efforts to reduce postoperative infection, infection burden has actually increased in the selected registries over time.

Background: Bilateral pelvic discontinuity is characterized by complete dissociation of the superior and inferior pelvis secondary to bone loss or fracture. The end result is a freely mobile inferior pelvis at the level of each discontinuity which presents a significant reconstruction challenge. This clinical entity has not been described previously, and the results of surgical treatment are not known. Methods: We retrospectively reviewed all identified cases of pelvic discontinuity (PD) treated with revision THA at one institution. We identified 133 pelvic discontinuities. Within this group, 6 patients had bilateral simultaneous PDs. Preoperative, intraoperative, and postoperative data and radiographic imaging were reviewed preoperatively and postoperatively for the characteristics of the dissociation and assessing PD healing and fixation of components after surgery. Results: There were no preoperative factors that could distinguish these patients from the rest of the group of discontinuities (3 rheumatoid arthritis, 2 osteonecrosis of the femoral head, 1 developmental dysplasia). The reconstructions performed included 2 cup/cage, 5 posterior plating and uncemented cup, 3 cage alone, and 2 cups only. Ten of 12 hips had at least 1 complication postoperatively. At final follow-up, only 1 patient (17%) had radiographic evidence that both discontinuities had healed (posterior plate with uncemented cup). Conclusions: Bilateral pelvic discontinuity is rare but presents the surgeon with a major reconstructive challenge. Only 1 patient went on to radiographic healing with current treatment strategies. Continued motion of the contralateral pelvic dissociation may account for the high failure rates. Surgeons should be aware of the challenges presented by this diagnosis and develop strategies to improve outcomes.

Background: Hip and knee arthroplasties are common and successful procedures, however, success and durability are not guaranteed. The revision burden, defined as the ratio of implant revisions to the total number of arthroplasties in a specific period, is a measure of the steady state of arthroplasty success in a given registry. This study examines the hypothesis that revision burden would be similar among contemporary joint replacement registries and improving over time compared with historic controls. Methods: We evaluated the national joint registries of 5 health systems (Australian Orthopaedic Association National Joint Replacement Registry [AOANJRR]; National Joint Registry of England, Wales, Northern Ireland, and the Isle of Man; New Zealand Joint Registry [NZJR]; Swedish Hip Arthroplasty Register [SHAR] and Swedish Knee Arthroplasty Register [SKAR]; and the American Joint Replacement Registry [AJRR]) for hip and knee revision burden over the past 4 years or since registry inception. Historic controls were obtained from previously published reports. Results: The 2014 hip revision burden varied from 9.7 percent (NJR) to 11.9 percent (NZJR), and the unweighted average was 10.4 percent. The 2011, 2012, and 2013 mean hip revision burden was 11.9, 11.9, and 11.4 percent. The 2014 knee revision burden varied from to 6.0 percent (NJR) to 8.1 percent (AJRR), and the unweighted average for the 5 registries studied was 7.0 percent. The 2011, 2012, and 2013 mean knee revision burden was 6.9, 7.0, and 7.0 percent. Historically, the observed hip revision burden was 15.8 percent and the knee revision burden 8.0 percent. Conclusions: Revision burden has gradually decreased for hip replacements and has remained relatively constant for knee replacements both for the last 4 years and compared to historic controls. Knee revision burden was lower than hip revision burden for each period examined. Revision burden is one measure that may be helpful in following the effect of changes in surgical technique and implant design over time in registry populations and may be a helpful way to compare overall results between registries.