Geometry of Torsional Malalignment Syndrome: Trochlear Dysplasia but Not Torsion Predicts Lateral Patellar Instability.

BACKGROUND: The clinical impact of increased torsion on patellar instability and patellofemoral pain syndrome (PFPS) has been suggested by several studies. HYPOTHESIS: The hypotheses of this study were that (1) torsional malalignment (TM) is characterized by a positive correlation between different malalignment parameters that represent an overall picture of the malalignment syndrome and (2) an increase in overall torsion is the underlying difference between patellar instability and isolated patellofemoral pain. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: Between April 2015 and July 2017, a total of 428 patients were treated for lateral patellar dislocation (LPD), and 333 patients were treated for PFPS. Sixty-two patients (14.5%) with patellar instability (LPD group) and 29 patients (8.7%) with patellofemoral pain (PFPS group) had additional TM and were included in this study. All patients underwent magnetic resonance imaging for torsional alignment and patellar tracking, including femoral antetorsion, tibial torsion, knee rotation, tibial tuberosity-trochlear groove (TT-TG) distance, tibial tuberosity-posterior cruciate ligament (TT-PCL) distance, Dejour classification of trochlear dysplasia, lateral trochlear inclination (LTI) angle, and patellar height. RESULTS: The LPD and PFPS groups differed significantly in terms of trochlear dysplasia (P < .001), LTI angle (P < .001), and TT-TG distance (P = .0167) but did not differ in terms of femoral antetorsion (20.02° ± 8.80° vs 20.03° ± 7.91°, respectively; P = .8545), tibial torsion (39.53° ± 9.23° vs 41.24° ± 7.28°, respectively; P = .3616), or knee rotation (10.42° ± 5.16° vs 8.48° ± 7.81°, respectively; P = .0163). Only measures of TT-TG distance and TT-PCL distance and measures of TT-TG distance and knee rotation were positively correlated. Trochlear dysplasia (type B-D) was identified as the only significant predictor of patellar instability. CONCLUSION: TM in patients with either PFPS or LPD does not appear to be characterized by a fixed constellation of different malalignment parameters. Between groups, the parameters differed significantly only in terms of trochlear dysplasia and the TT-TG distance, and trochlear dysplasia (type B-D) (but not torsion) was identified as a predictor of lateral patellar instability.

Tumor immunoevasion via acidosis-dependent induction of regulatory tumor-associated macrophages.

Many tumors evolve sophisticated strategies to evade the immune system, and these represent major obstacles for efficient antitumor immune responses. Here we explored a molecular mechanism of metabolic communication deployed by highly glycolytic tumors for immunoevasion. In contrast to colon adenocarcinomas, melanomas showed comparatively high glycolytic activity, which resulted in high acidification of the tumor microenvironment. This tumor acidosis induced Gprotein-coupled receptor-dependent expression of the transcriptional repressor ICER in tumor-associated macrophages that led to their functional polarization toward a non-inflammatory phenotype and promoted tumor growth. Collectively, our findings identify a molecular mechanism of metabolic communication between non-lymphoid tissue and the immune system that was exploited by high-glycolytic-rate tumors for evasion of the immune system.

No improvement in reducing outliers in coronal axis alignment with patient-specific instrumentation.

PURPOSE AND HYPOTHESIS: Patient-specific instrumentation (PSI) uses 3D preoperative imaging to produce individualized cutting blocks specific to patients' anatomy and according to the preoperative plan with the aim to reduce the number of mechanical leg alignment (MLA) outliers, to improve implant positioning and to decrease surgery time. The primary purpose of this study was to investigate the efficacy of a specific PSI in comparison with standard instrumentation (SI) in reducing the number of MLA outliers. It was hypothesized that the number of MLA outliers would be significantly lower in the PSI group. METHODS: A multicenter randomized controlled trial was implemented. There were 59 patients in the PSI group and 66 in the SI group. The absolute number of outliers outside the ± 3° target neutral MLA was compared between the groups with a Chi-square test. As secondary outcomes, the Knee Society Score (KSS) and the Knee Injury and Osteoarthritis Outcome Score (KOOS) were compared between the groups preoperatively and at 90-day follow-up. RESULTS: There were 15 (26.3%) MLA outliers in the PSI group and 8 (12.3%) in the SI group. The number of outliers was not independent from the group ( X2 (1) = 3.8, p = 0.04; Relative risk = 1.5). Preoperatively, there were no significant differences between the groups when comparing their KSS and KOOS sub-scores. At 90 days postoperatively, the patients in the SI group showed better KOOS-Quality of Life (KOSS-QOL) in comparison with the PSI group (p < 0.0001). CONCLUSION: The use of PSI did not significantly reduce the number of MLA outliers in comparison with SI. There were no differences when comparing the achieved mean MLA of both groups. LEVEL OF EVIDENCE: Level I, prospective randomized controlled trial.