Rhodes, Nicholas G.

Purpose To assess the reliability, predictability, and discriminative capacity of 3 anatomic measurements, tibial tubercle‐trochlear groove (TT‐TG), tibial tubercle‐posterior cruciate ligament, and patellar tendon‐lateral trochlear ridge (PT‐LTR), where PT‐LTR may offer a complementary approach to assessing recurrent patellofemoral instability (PFI) risk. Methods Patients diagnosed with PFI before primary patellofemoral stabilization surgery at a single institution between 2022 and 2024 were included. A control group without PFI was propensity matched 1:1 for age, sex, and laterality. Magnetic resonance images were evaluated to measure TT‐TG, tibial tubercle‐posterior cruciate ligament, and PT‐LTR. A priori power analysis determined the cohort size. Statistical analyses compared differences between the PFI and control groups with Student t‐tests, receiver operating characteristic analyses, and area under the curve with resultant sensitivity, specificity, and an optimal cutoff. Results Patients included 50 knees with PFI (28 women, 22 men; mean age 18 ± 5 years). The control group included 50 knees (27 women, 23 men; mean age 18 ± 4 years). Excellent inter‐ and intra‐rater reliability (intraclass correlation coefficient > 0.7) was shown for TT‐TG and PT‐LTR in the PFI and control groups. The distances for TT‐TG, tibial tubercle‐posterior cruciate ligament, and PT‐LTR were significant predictors ( P ≤ .025) of PFI. The average PT‐LTR distance difference for the PFI and control groups was 7.0 mm ( P < .001). PT‐LTR showed an area under the curve of 0.80 and, when ≥4.6 mm, was 66% sensitive and 92% specific for PFI. Conclusions The PT‐LTR distance is a reliable and discriminative metric for identifying PFI in both pediatric and adult populations. A PT‐LTR cutoff value of 4.6 mm showed diagnostic discrimination and substantially high specificity for recurrent PFI, indicating strong ability to identify patients with instability. Level of Evidence Level III, retrospective case control study.

This slideshow presentation provides a practical image-based road map to essential spinal and pelvic radiographic measurements, with stepwise instructions and reference values, for assessment and management of spinal disorders.

Accurate assessment of distal tibiofibular syndesmotic injuries is essential to prevent chronic instability and poor functional outcomes, and conventional radiography, CT, and MRI play complementary and critical roles in the imaging of these injuries.

ABSTRACT Based on anecdotal observation of fatty infiltration (FI) of the opponens pollicis (OPP) muscle in patients with thumb carpometacarpal (CMC) Osteoarthritis (OA), we sought to examine the association of FI with CMC OA. We reviewed 747 consecutive 3 T wrist magnetic resonance imaging (MRI) studies for evidence of FI in the thenar muscles. This population was divided into two cohorts based on radiographic analysis: a cohort without thumb CMC OA ( n = 440) and a second cohort with thumb CMC OA ( n = 307), staged according to the Eaton–Littler classification. Statistical analysis using logistic regression was performed to investigate clinical factors associated with the presence of FI in the thenar muscles. FI was present in 133 patients with CMC OA (43.3%). FI, when present, was located only in the OPP. We found no OPP FI in the cohort without CMC OA (440 patients). Among patients with CMC OA, increasing age, male sex and advanced OA stage were significantly associated with the presence of OPP FI. OPP FI is a frequent finding in CMC OA. This FI could affect the biomechanical function of the OPP. In the future, we plan to analyze clinical outcomes in CMC OA patients with and without FI, and more focused in vivo studies of OPP function. OPP FI could potentially affect the function and the stability of the thumb CMC joint in patients with CMC OA. Orthopaedic Research Society. Journal of Orthopaedic Research® 00:00–00, 2026.

Bone surface lesions include a variety of benign and malignant tumors and nonneoplastic entities, and knowledge of the different cell types and cortical bone surface anatomy equips radiologists to provide a useful differential diagnosis for these lesions.

OBJECTIVES: To compare whether femoral version more closely mirrors the contralateral femur or a population norm estimate of 15 degrees of anteversion. METHODS: Design: Radiologic observational study. Setting: Level I Trauma Center. Patient Selection Criteria: Patients with no history of anatomy-altering femoral injury who underwent bilateral lower extremity computed tomography scans. Outcome Measures and Comparisons: Computed tomographies were analyzed to measure femoral version on each side. The asymmetry in femoral version between left and right in each patient (interfemoral rotational variance [IRV]) was recorded. The difference of each femur's version from a proposed population mean of 15 degrees of anteversion was also recorded. RESULTS: A total of 219 patients with a mean femoral version of 14.9 degrees ± 10.5 degrees of anteversion were included. Mean IRV was 5.3 degrees, compared with 8.2 degrees of mean variation from the population norm of 15 degrees of anteversion (P < 0.001). Five percent of patients had IRV >15 degrees compared with 15% that had femoral rotation >15 degrees from the population mean of 15 degrees (P < 0.001). CONCLUSIONS: In the setting of a comminuted diaphyseal femur fracture, knowledge of the appropriate target for restoration of rotational alignment is critical. This radiologic cohort study found that on average, femoral version more closely mirrors an individual patient's contralateral femur as opposed to a population norm of 15 degrees of anteversion.

Epidural steroid injections are commonly performed using fluoroscopic or CT guidance. With both modalities, the injection of contrast material is necessary before steroid administration to ensure adequate epidural flow and exclude non-epidural flow. While fluoroscopic guidance is conventional, CT is utilized at some centers and can be particularly helpful in the setting of challenging or postoperative anatomy. It is important for proceduralists to be adept at evaluating contrast media flow patterns under both modalities. The goal of this review article is to describe and provide examples of epidural and non-epidural flow patterns on both conventional fluoroscopy and CT. Specific non-epidural patterns discussed include intrathecal flow, intradural/subdural flow, vascular uptake, flow into the retrodural space of Okada, inadvertent facet joint flow, and intradiscal flow.

Purpose To develop a machine learning model capable of identifying subscapularis tears before surgery based on imaging and physical examination findings. Methods Between 2010 and 2020, 202 consecutive shoulders underwent arthroscopic rotator cuff repair by a single surgeon. Patient demographics, physical examination findings (including range of motion, weakness with internal rotation, lift/push‐off test, belly press test, and bear hug test), and imaging (including direct and indirect signs of tearing, biceps status, fatty atrophy, cystic changes, and other similar findings) were included for model creation. Results Sixty percent of the shoulders had partial or full thickness tears of the subscapularis verified during surgery (83% of these were upper third). Using only preoperative imaging‐related parameters, the XGBoost model demonstrated excellent performance at predicting subscapularis tears (c‐statistic, 0.84; accuracy, 0.85; F1 score, 0.87). The top 5 features included direct signs related to the presence of tearing as evidenced on magnetic resonance imaging (MRI) (changes in tendon morphology and signal), as well as the quality of the MRI and biceps pathology. Conclusions In this study, machine learning was successful in predicting subscapularis tears by MRI alone in 85% of patients, and this accuracy did not decrease by isolating the model to the top features. The top five features included direct signs related to the presence of tearing as evidenced on MRI (changes in tendon morphology and signal), as well as the quality of the MRI and biceps pathology. Last, in advanced modeling, the addition of physical examination or patient characteristics did not make a significant difference in the predictive ability of this model. Level of Evidence Level III, diagnostic case‐control study.