Aims:The aim of this study was to quantify the contribution of patient-, surgeon-, and institution-level factors to variation in dual-mobility component use in primary total hip arthroplasty (DM-THA) in England. We sought to determine whether current patterns reflect appropriate patient selection or unwarranted practice variation. We hypothesized that surgeon- and institution-level factors account for a greater proportion of variation in DM-THA use than patient-level characteristics. Methods:We analyzed 238,455 primary THAs recorded in the National Joint Registry which were linked with Hospital Episode Statistics for England between 1 January 2018 and 31 December 2022. Using cross-classified multilevel logistic regression modelling, we partitioned variation in DM-THA use attributable to patient, surgeon, and institutional factors. Patient risk factors were included as fixed effects, with random effects specified for surgeons and hospitals to account for clustering. Results:Of the total cohort, 7,032 underwent DM-THA. These patients were older, more frail, and more frequently treated for neck of femur fractures. Surgeon-level factors explained 32.4% and institutional factors 22.9% of variation in DM-THA use. Patient-level factors accounted for approximately 10% of the variance (marginal R² = 0.10), while the full model explained 59.8% of variation (conditional R² = 0.598). Findings were consistent in analyses restricted to high-volume surgeons. Conclusion:Variation in DM-THA use is predominantly driven by surgeon and institutional practice rather than patient characteristics. Prognostic tools which can identify patients at high dislocation risk, to guide inclusion criteria for targeted randomized trials, are needed to establish evidence-based guidance for DM implant selection and reduce unwarranted practice variation.
Aims:Two-stage exchange arthroplasty with an antibiotic-eluting cement spacer remains the predominant strategy in the USA for managing chronic periprosthetic joint infection (PJI) following total hip arthroplasty (THA). The aim of this study was to evaluate a commercially available, partially intraoperatively fabricated articulating high-dose antibiotic cement spacer, focusing on survival, complications, and patient-reported outcomes. Methods:A total of 298 patients (302 THAs) underwent two-stage exchange arthroplasty for PJI using a specific articulating antibiotic spacer between August 2005 and May 2022. Patients with a previous failed two-stage exchange were excluded, although 121 THAs (302, 40%) had undergone previous PJI-related procedures. The mean age of the patients was 65 years (SD 11), the mean BMI was 32 kg/m2 (SD 7), and 116 (38%) were female. Most patients were classified as McPherson host B (158; 52%) and limb grade 2 (165; 55%), and 265 (88%) met the 2011 Musculoskeletal Infection Society criteria. The mean follow-up was six years (2 to 16). . Results:At five years after reimplantation, survival free of reinfection, aseptic rerevision, any rerevision, or any reoperation were 89% (95% CI 85.2 to 93.1), 93% (95% CI 89.3 to 96.1), 86% (95% CI 81.3 to 90.3), and 80% (95% CI 74.7 to 84.9), respectively. Dislocation accounted for most aseptic rerevisions (15/20). McPherson host C (HR 3.7 (95% CI 1.4 to 9.6); p = 0.007) and limb grade 3 (HR 3.3 (95% CI 1.0 to 11.1); p = 0.049) were significantly associated with an increased risk of reinfection. The mean Harris Hip Score at the latest follow-up was 76 (29 to 100). A total of 17 patients underwent revision or removal of a spacer for concerns about persistent infection and two for dislocation of the spacer. Eight patients underwent a non-rerevision reoperation during the spacer interval for wound drainage (n = 5), dislocation of the spacer (n = 2), and perispacer fracture (n = 1). A total of 26 spacer-related complications were treated nonoperatively (15 perispacer fractures, 11 dislocations). Dislocation of the spacer was strongly associated with dislocation after reimplantation (HR 6.2 (95% CI 2.3 to 16.9); p < 0.001). Conclusion:This commercially available, partially intraoperatively fabricated articulating spacer showed excellent reinfection-free five-year survival (89%). Spacer-related fracture and dislocation each occurred in 5% of patients. Dislocation of the spacer significantly increased the risk of dislocation following reimplantation, supporting the use of higher-stability bearings in these high-risk patients.
Aims:This study reports the interim outcomes of a randomized controlled trial comparing the accuracy of component positions, early functional outcomes, patient-reported outcome measures, and complications in conventional jig-based unicompartmental knee arthroplasty with navigational control (CO UKA) with robotic arm-assisted unicompartmental knee arthroplasty (RO UKA) for patients who have medial compartment knee osteoarthritis (OA). Methods:In total, 107 patients with symptomatic medial compartment OA were prospectively randomized to undergo CO UKA (n = 52) or RO UKA (n = 55), representing the currently available recruited cohort. Patients in both treatment groups had CT-based surgical planning. All procedures were completed using the medial parapatellar approach, and all patients received a standardized postoperative rehabilitation programme. Predefined study outcomes were recorded at regular intervals for two years after surgery. Results:RO UKA was associated with increased accuracy in executing the planned femoral (p < 0.001) and tibial (p < 0.001) component positions compared with CO UKA. RO UKA was associated with reduced inpatient pain scores (p < 0.001), decreased inpatient opioid analgesia consumption (p = 0.008), and shorter length of hospital stay (p = 0.004) compared with CO UKA. There were no differences between the treatment groups in the Oxford Knee Score (p = 0.299), Knee Injury and Osteoarthritis Outcome Score (p = 0.261), and Western Ontario and McMaster Universities Arthritis Index (p = 0.281) at two-year follow-up. RO UKA was associated with improved Forgotten Joint Score (FJS) at six-month (p = 0.002) and two-year (p = 0.021) follow-up. Patient recruitment declined during the trial as an increasing proportion of eligible patients expressed a preference for RO UKA, and operating surgeons experienced reduced clinical equipoise between the treatment groups. Conclusion:The interim results of this study show that RO UKA was associated with increased accuracy in achieving the planned femoral and tibial component positions, improved early functional recovery, and decreased length of hospital stay compared with CO UKA. RO UKA was associated with higher FJSs compared with CO UKA at short- to mid-term follow-up.
Aims:The study aimed to investigate the agreement between Constant-Murley score (CMS) and the shoulder subjective value (SSV); and the association of poor self-evaluated outcome with shoulder pain, range of motion (ROM) limitation, and shoulder strength after fixation of proximal humerus fractures. Methods:The study included 74 shoulders in 72 patients (mean age 56 years (SD 14), 40 male (56%)) who underwent locking plate fixation of displaced proximal humerus fractures between January 2015 and January 2024. We evaluated CMS, SSV, pain scores (visual analogue scale), and ROM measurements at the most recent (minimum one-year) follow-up. Agreement statistics between CMS and SSV were used descriptively, rather than to test true substitutability, because CMS and SSV are nonequivalent constructs. Results:The Bland-Altman analysis showed differences between CMS and SSV, as the mean difference between CMS and SSV (-14.21 (95% CI -17.25 to -11.18)) did not include the zero-difference line. The Pitman's test suggested that the variances were significantly different (p = 0.029). Firth's penalized method of logistic regression revealed that only the presence of shoulder pain was associated with an increased likelihood of a poor functional outcome (SSV ≤ 69.4) (coefficient 3.5 (95% CI 1.53 to 6.47); p < 0.001). The SSV threshold (69.4) was derived from the CMS ≤ 55 threshold on the same dataset and therefore may have nonindependence. However, a sensitivity analysis using a priori SSV threshold (75) of patient-acceptable symptom state (PASS) also showed that presence of pain was associated with increased likelihood of a lower SSV. Limitations in ROM (elevation, external rotation, and internal rotation) and lower shoulder strength were not independently associated with a poor SSV. In shoulders that did not develop avascular necrosis (n = 66), the bivariate exploratory analysis between presence of pain and predefined injury and radiological factors showed that malreduction (χ2 (1, n = 66) = 6.8; p = 0.009) and absent postoperative medial hinge (χ2 (1, n = 66) = 4.6; p = 0.032) were significantly associated with more frequent presence of shoulder pain. Conclusion:Physician-evaluated outcomes (as measured by the CMS) and patient self-evaluated outcomes (as measured by the SSV) are likely to differ systematically after internal fixation of proximal humerus fractures. Additionally, shoulder pain is independently associated with a poor self-evaluated functional outcome.
