Reduced Revision Rates in Total Shoulder Arthroplasty With Crosslinked Polyethylene: Results From the Australian Orthopaedic Association National Joint Replacement Registry.

BACKGROUND: Loss of glenoid fixation is a key factor affecting the survivorship of primary total shoulder arthroplasty (TSA). It is not known whether the lower revision rates associated with crosslinked polyethylene (XLPE) compared with those of non-XLPE identified in hip and knee arthroplasty apply to shoulder arthroplasty. QUESTIONS/PURPOSES: We used data from the Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR) to compare the revision rates of primary stemmed anatomic TSA using XLPE to procedures using non-XLPE. In patients receiving a primary stemmed anatomic TSA for osteoarthritis, we asked: (1) Does the rate of revision or reason for revision vary between XLPE and non-XLPE all-polyethylene glenoid components? (2) Is there any difference in the revision rate when XLPE is compared with non-XLPE across varying head sizes? (3) Is there any difference in survival among prosthesis combinations with all-polyethylene glenoid components when they are used with XLPE compared with non-XLPE? METHODS: Data were extracted from the AOANJRR from April 16, 2004, to December 31, 2020. The AOANJRR collects data on more than 97% of joint replacements performed in Australia. The study population included all primary, stemmed, anatomic TSA procedures performed for osteoarthritis using all-polyethylene glenoid components. Procedures were grouped into XLPE and non-XLPE bearing surfaces for comparison. Of the 10,102 primary stemmed anatomic TSAs in the analysis, 39% (3942 of 10,102) used XLPE and 61% (6160 of 10,102) used non-XLPE. There were no differences in age, gender, or follow-up between groups. Revision rates were determined using Kaplan-Meier estimates of survivorship to describe the time to the first revision, with censoring at the time of death or closure of the database at the time of analysis. Revision was defined as removal, replacement, or addition of any component of a joint replacement. The unadjusted cumulative percent revision after the primary arthroplasty (with 95% confidence intervals [CIs]) was calculated and compared using Cox proportional hazard models adjusted for age, gender, fixation, and surgeon volume. Further analyses were performed stratifying according to humeral head size, and a prosthesis-specific analysis adjusted for age and gender was also performed. This analysis was restricted to prosthesis combinations that were used at least 150 times, accounted for at least four revisions, had XLPE and non-XLPE options available, and had a minimum of 3 years of follow-up. RESULTS: Non - XLPE had a higher risk of revision than XLPE after 1.5 years (HR 2.3 [95% CI 1.6 to 3.1]; p < 0.001). The cumulative percent revision at 12 years was 5% (95% CI 4% to 6%) for XLPE and 9% (95% CI 8% to 10%) for non-XLPE. There was no difference in the rate of revision for head sizes smaller than 44 mm. Non-XLPE had a higher rate of revision than XLPE for head sizes 44 to 50 mm after 2 years (HR 2.3 [95% CI 1.5 to 3.6]; p < 0.001) and for heads larger than 50 mm for the entire period (HR 2.2 [95% CI 1.4 to 3.6]; p < 0.001). Two prosthesis combinations fulfilled the inclusion criteria for the prosthesis-specific analysis. One had a higher risk of revision when used with non-XLPE compared with XLPE after 1.5 years (HR 3.7 [95% CI 2.2 to 6.3]; p < 0.001). For the second prosthesis combination, no difference was found in the rate of revision between the two groups. CONCLUSION: These AOANJRR data demonstrate that noncrosslinked, all-polyethylene glenoid components have a higher revision rate compared with crosslinked, all-polyethylene glenoid components when used in stemmed anatomic TSA for osteoarthritis. As polyethylene type is likely an important determinant of revision risk, crosslinked polyethylene should be used when available, particularly for head sizes larger than 44 mm. Further studies will need to be undertaken after larger numbers of shoulder arthroplasties have been performed to determine whether this reduction in revision risk associated with XLPE bears true for all TSA designs. LEVEL OF EVIDENCE: Level III, therapeutic study.

Incidence of flexion-type supracondylar fractures at a single Australian level one Paediatric Trauma Centre.

BACKGROUND: Supracondylar fractures are the most common elbow fracture. There have been no studies published analysing flexion-type fractures in the Australian paediatric population. This paper aims to investigate flexion-type supracondylar fractures in an Australian paediatric population. Eight hundred and three paediatric supracondylar elbow fractures were retrospectively reviewed at one hospital over a 5 year time period. The focus was on flexion-type fractures. METHODS: Supracondylar fractures that presented to the Women's and Children's Hospital Emergency Department between 2015 and 2020 were retrospectively reviewed. Fractures were classified on plain radiographs according to the Modified Gartland Classification System. Injury and treatment data were collected for flexion-type fractures. RESULTS: Twenty-one (2.6%) of fractures were flexion-type. The average age of injury was 6.8 years old. Flexion-type fractures were more common in females (62%) and with high energy mechanisms (81%). Ulnar nerve palsies occurred in five cases (24%). Two ulna nerve palsies did completely resolve at 3 months follow up. One open fracture occurred. No vascular injuries occurred. Ten of the 21 flexion-type fractures (48%) were treated surgically. CONCLUSIONS: The authors conclude that: flexion fractures are uncommon, they occur more often after high energy mechanisms such as falls from monkey bars, swings, or trampolines. Flexion-type fractures occur more often in slightly older females. The ulnar nerve is most frequently injured and in the current study-exclusively injured. At 3 month follow up, spontaneous nerve recovery had occurred in three of the five cases (60%).