Increased Rates of Late Periprosthetic Fractures in Larger Hydroxyapatite-Coated Cementless Stems: Are Collared Stems a Better Alternative for Total Hip Arthroplasty?

BACKGROUND

Cementless hip stems are widely used for total hip arthroplasty (THA) and have demonstrated excellent survivorship. This study aimed to investigate the effects of stem size and calcar collars on rates of revision due to periprosthetic fracture.

METHODS

All primary THA procedures recorded by the Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR) from September 1999 to December 2021 for a diagnosis of osteoarthritis using a single cementless hip stem with modern bearings were included. The primary outcome measure was revision due to periprosthetic fracture. Stems were divided into 2 groups for comparison, large (size 14 to 20) and small-medium (6 to 13). A subanalysis was performed for collared stems. A total of 59,518 primary THA procedures were included.

RESULTS

The cumulative percent revision for periprosthetic fracture was significantly higher for large stems compared to small-medium stems (hazard ratio [HR] = 1.57 [95% confidence interval {CI} 1.18, 2.09] P = .002). Furthermore, collared stems had significantly lower revision rates due to late periprosthetic fracture compared to collarless variants (2 week + HR = 4.55 [95% CI 3.23, 6.42], P < .001). Large collarless stems were found to have greater revision rates due to fracture compared to small-medium collarless stems (HR = 1.55 [95% CI 1.13, 2.12] P = .006), but no difference was found between collared groups (HR = 1.37 [95% CI 0.68, 2.78] P = .382).

CONCLUSION

Large cementless hip stems have a higher rate of revision due to periprosthetic fracture compared to small-medium stems. Using a collared stem reduces the rate of periprosthetic fracture.

Municipal Compost Public Health, Waste Management, and Urban Agriculture: A Decadal Study of Fugitive Pb in City of Boston, Massachusetts, USA

Compostable materials constitute roughly half of waste generated globally, but only 5% of waste is actually processed through composting, suggesting that expanding compost programs may be an effective way to process waste. Compostable waste, if properly collected and processed, has value-added end use options including: residential and park landscaping, remediation of brownfield sites, and as growing media in urban agriculture (UA). Since 2001, our lab has partnered with The Food Project, a non-profit focused on youth leadership development through urban farming. From 2006 to 2022 we collected compost materials that were delivered to the farm from a variety of local sources and analyzed a suite of biogeochemical properties including lead (Pb) concentrations, organic carbon, and grain size distribution. Pb concentrations of Boston's municipal compost always exceeded the current City of San Francisco soil and compost purchase standard (80 μg/g). In 2012 Boston's composting program was halted when it exceeded the 400 μg/g Environmental Protection Agency's Pb in soil benchmark. Urban Pb is geomobile and must be managed to minimize resuspension and transport of fines whose Pb concentration is often elevated compared to bulk compost. Consequently, urban farmers have to source lower Pb compost from suburban suppliers at significantly greater cost. Over a 15 year period and through several city vendor contracts, Pb concentrations in municipal compost remain at levels that warrant continued surveillance and risk assessment.

Design, Construction, and Early Results of a Formal Local Revision Knee Arthroplasty Registry

National registries for primary and revision knee arthroplasty in Australia, New Zealand, and Europe have been successful in ensuring quality control and providing information to drive crucial research. However, they face challenges in delivering the granularity of data useful at a local hospital level. Our aim was to address these challenges by designing and initiating a local revision knee arthroplasty registry and combining the data with national figures to better evaluate the types of revisions undertaken, and improve patient outcomes and care. All revision knee arthroplasty cases in our center were analyzed from April 2014 to December 2015 using our standardized diagnostic algorithm. Information such as reason and type of revision was collected. Results were compared with Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR) data. Primary outcome was comparison against our center's historical data between January 1999 and December 2013 and secondary outcome was comparison against national data prior to and after our intervention. Between April 2014 and December 2015, our center performed 35 revision knee arthroplasties. When compared with our center's historical data, we observed lower rates of revision knee arthroplasties due to "pain" (14.2 vs. 36.7%) with corresponding lower rates of patella button only revision (8.6 vs. 39.2%). Compared with national data before our intervention, we had lower revision rates from infection (14.2 vs. 22.3%) and loosening/lysis (11.4 vs. 29.2%). We undertook more minor revisions (45.7 vs. 30.5%) and similar total revisions (25.7 vs. 25.3%). Similar trends were seen in comparison to national data after our intervention. Our study shows that a local registry can be designed and successfully implemented for revision knee arthroplasty surgery. Data can be easily compared with historic and current hospital and national registry data trends to assess quality and robustness of revision arthroplasty programs. Our early results suggest our center has succeeded in reducing incidences of major revisions, complications, and the risk of re-revision surgery. This will improve the quality of our service with a significant cost reduction for our local health care budget.