Early anterolateral thigh pain after direct anterior total hip arthroplasty (DAA-THA) is common, and more severe symptoms than expected in the usual postoperative course can be difficult to interpret clinically. This study evaluated whether a landmark-based ultrasonographic pattern of postoperative fluid collection (POFC) at a reference level corresponding to a reported course of the proximal neurovascular bundle is associated with early pain and knee extensor strength. In this prospective cohort study, ultrasonography was performed at 1 week postoperatively in 182 patients (182 hips) who underwent DAA-THA. At a prespecified reference cross-section corresponding to a reported level where the proximal neurovascular bundle crosses the femoral midline, POFC extending medially beyond the femoral midline was classified as a midline-crossing POFC. Co-primary outcomes were proximal anterolateral thigh pain while walking, assessed using a numerical rating scale, and knee extension torque at 1 week. P-values for the co-primary outcomes were Holm-adjusted. The Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) subscales were analyzed longitudinally. Of the 182 hips, 37 were classified as midline-crossing POFC and 145 as non–midline-crossing POFC. Compared with the non–midline-crossing group, the midline-crossing group had greater proximal anterolateral thigh pain during walking (adjusted mean difference, 3.35 points; 95
Artificial intelligence (AI) and machine-learning methods are increasingly discussed in relation to robotic-assisted total knee arthroplasty (TKA). However, robotic assistance, computer navigation, and AI-based prediction represent distinct functions that are often conflated under the single label “AI-assisted robotic TKA,” obscuring the state of evidence for each. This review clarifies these distinctions and maps the current evidence for AI-related functions across the TKA pathway, keeping AI prediction evidence analytically separate from robotic execution evidence at the level of each clinical function. We performed a critical narrative review and evidence map of peer-reviewed literature relevant to robotic-assisted TKA, navigation-assisted TKA, AI/ML prediction models, digital planning, implant sizing, intraoperative decision support, postoperative monitoring, implementation, and economic evaluation. Evidence was interpreted according to clinical function, comparator structure, validation status, and translational maturity. Because the available literature is methodologically and conceptually heterogeneous, quantitative pooling and formal comparative-effectiveness claims were not attempted. Robotic-assisted and navigation-assisted TKA have the most mature evidence base for improving technical precision, particularly implant positioning and radiographic alignment. In contrast, AI/ML evidence is concentrated mainly in adjacent pathway functions, including radiographic interpretation, implant-sizing prediction, patient-selection support, dissatisfaction prediction, outcome modelling, perioperative risk stratification, and postoperative monitoring. Direct clinical evidence demonstrating that AI-enabled robotic TKA provides incremental patient-level benefit beyond conventional robotic assistance remains limited. Current studies are constrained by inconsistent terminology, short follow-up, limited external validation, incomplete reporting of AI components, heterogeneous outcomes, cost uncertainty, and uncertain generalizability across patient populations and healthcare settings. AI should not currently be treated as a single validated surgical intervention in TKA. Rather, it represents a family of emerging pathway-level functions that may support preoperative planning, intraoperative decision support, patient selection, risk communication, and longitudinal recovery monitoring. Future studies should explicitly define the AI component being evaluated, distinguish AI functionality from robotic or navigation assistance, use standardized comparators, and assess long-term patient-reported outcomes, implant survivorship, safety, cost-effectiveness, and equity across multicenter prospective cohorts or randomized trials.
Abstract Introduction The direct anterior approach (DAA) for total hip arthroplasty (THA) has historically been associated with a learning curve affecting both operative efficiency and early complications. Whether contemporary adult-reconstruction fellowship training modifies that curve is not established. We compared 90-day complication rates and operative times between newly graduated fellowship-trained DAA surgeons and one experienced DAA surgeon at a single high-volume center. Methods This retrospective cohort study included 600 primary THAs performed via a DAA from a single institution between November 2019 and February 2025 with a minimum of 90-day follow-up. Intra- and post-operative complications were compared between the following two groups: the first 100 cases of each of three junior fellowship-trained arthroplasty surgeons (“Junior”) and the most recent 300 cases of a senior fellowship-trained arthroplasty surgeon (“Senior”). The study was powered to detect a 5% absolute difference in overall complication rates. Patient-reported outcome measures (PROMs) were analyzed as exploratory secondary endpoints. Results Operative complications were infrequent in both cohorts, with a numerically higher rate in the Junior group that did not reach statistical significance (Junior 27 [9.0%] vs Senior 20 [6.7%]; absolute difference + 2.3%, 95% CI − 2.0% to + 6.6%, p = 0.362). No subgroup comparison reached statistical significance: DVT (1.0 vs 0.7%, p = 1.000), PE (0.3 vs 0.3%, p = 1.000), hematoma (0.3 vs 1.0%, p = 0.624), dislocation (1.3 vs 0.3%, p = 0.373), periprosthetic fracture (1.7 vs 1.0%, p = 0.725), neurapraxia (1.3 vs 2.0%, p = 0.752), prosthetic joint infection (1.0 vs 0.3%, p = 0.624), or wound complications (3.3 vs 2.0%, p = 0.448). All subgroup analyses were exploratory and underpowered for individually rare events. Medical events were infrequent and similar between groups (Junior 13 [4.3%] vs Senior 17 [5.7%], p = 0.575). Combining operative and medical complications, 40 events (13.3%) occurred in the Junior cohort and 37 (12.3%) in the Senior cohort ( p = 0.807). Operative time was significantly longer among Junior surgeons (92.3 vs 68.5 min, p < 0.001). In exploratory analyses limited by 90-day PROM follow-up of 35% (Junior) and 48% (Senior), 90-day SF-12 and WOMAC scores were similar among respondents; given the incomplete follow-up, these descriptive findings are best regarded as hypothesis-generating rather than conclusive about functional recovery. Conclusion Within a single high-volume center using standardized ERAS pathways, three fellowship-trained surgeons performing their first 100 DAA THAs had significantly longer operative times than one experienced DAA surgeon, with no evidence of a large difference in 90-day complication rates. Because the study was powered only to detect a 5% absolute difference, it cannot exclude smaller or rare-event differences and does not establish equivalence. These data generate the hypothesis that contemporary fellowship training combined with protocolized perioperative care shifts the early DAA learning curve toward efficiency rather than safety; confirmation requires an adequately powered, multicenter study.
Periprosthetic joint infection (PJI) remains a severe complication due to persistent bacterial biofilms. Rifampin is traditionally valued for its unique biofilm-penetrating properties, yet its clinical role is increasingly viewed as context-dependent. While current evidence supports the efficacy of rifampin in two-stage revision arthroplasty, its application in debridement, antibiotics, and implant retention (DAIR) remains a subject of ongoing debate. Landmark randomized trials once reported superior cure rates for DAIR combined with rifampin, but contemporary large-scale retrospective data show no statistically significant difference in remission rates, often accompanied by a significantly higher incidence of adverse events. Furthermore, the timing of administration is critical; early initiation within five days post-DAIR has been linked to increased treatment failure. These challenges, alongside profound drug-drug interactions, have spurred interest in localized delivery innovations like microencapsulation and nanoparticles. While these bioengineering approaches show preclinical promise in overcoming PMMA chemical incompatibility, they remain at the proof-of-concept stage. Consequently, rifampin should be employed as a targeted adjunct rather than a universal standard, requiring careful consideration of surgical strategy, patient tolerance, and optimal timing.
Abstract Background Studies on total knee arthroplasty (TKA) demonstrated increased positive patient-reported outcomes when the coronal plane alignment of the knee (CPAK) phenotype was preserved. However, reports on outcomes related to changes in CPAK following unicompartmental knee arthroplasty (UKA) remain limited. Methods One hundred forty-five patients undergoing unilateral medial UKAs with pre- and postoperative full-body anteroposterior standing radiographs were enrolled in the study. Angles in the coronal plane alignment, including medial proximal tibial angle (MPTA), lateral distal femoral angle (LDFA), arithmetic hip–knee–ankle angle (aHKA), and joint line obliquity (JLO), were measured. Postoperatively, patients were grouped into restored and altered CPAK groups. With a minimum 1-year follow-up (FU), patient-reported outcome measures, including the Forgotten Joint Score-12 (FJS-12), Oxford Knee Score (OKS), and 12-Item Knee Injury and Osteoarthritis Outcome Score (KOOS-12), were evaluated and compared between the two groups. Results Among 145 patients, 76 with true anteroposterior radiographs completed the final FU. The mean age, BMI, and FU time were 69.5 years, 27.19 kg/m2, and 23.2 months, respectively. The two most common preoperative CPAK phenotypes were type I (52.6%) and type II (32.9%). With no differences in preoperative MPTA, LDFA, Kellgren–Lawrence (KL), and Ahlbäck grade, 35 patients had their CPAK restored, and 41 had altered CPAK. The postoperative aHKA was not overcorrected toward valgus alignment (aHKA > 2 degrees) in either group, and similarly significant improvements were observed in FJS-12, OKS, and KOOS-12 scores from baseline. The altered CPAK group demonstrated significantly higher MPTA and JLO values than the restored CPAK group, corresponding to a shift in CPAK phenotype, most commonly from type I to IV or VII and from type II to VII or VIII. In addition, clinical outcomes of 65 patients with unsuitable radiographs for CPAK evaluation were similar to those of included patients in the final analysis. Conclusion Both restored CPAK and altered CPAK patients after medial UKA showed similar improvements in short-term patient-reported outcomes at a mean 23-month FU. Mid- to long-term clinical outcomes in patients with changes in knee phenotype should be evaluated.
