Kakar, Sanjeev

Abstract Objective. Four-dimensional CT (4DCT) enables visualization of dynamic wrist joint pathology but may be compromised by motion artifacts. Deep learning (DL)-assisted motion correction has the potential to enhance wrist 4DCT quality, but model development is hindered by scarce training data. To address this, we developed a model-based motion simulation framework that generated realistic 4DCT data with paired static ground truth images to demonstrate wrist motion correction using a physics-informed DL model trained with simulated data. Approach. Wrist motion was simulated by synchronizing rotational and translational movements of carpal bones and connective tissues. Elastic deformation guided by analytically-derived motion vector fields was applied to static wrist scans at neutral positions to create artifact-free images at multiple angular positions. Virtual motion-corrupted 4DCT images were produced via forward projection and reconstruction with synchronized gantry and wrist motion. Experimental data from 4DCT cadaver scans were collected to validate simulation quality. Low-intensity region score (LIRS), positivity, and entropy were used to assess simulated motion artifacts. A physics-informed motion correction network was adapted exclusively using simulated training data and subsequently deployed on simulated, real cadaveric, and in vivo 4DCT scans. LIRS and structural similarity index (SSIM) were used to evaluate motion correction quality. Wilcoxon signed-rank tests were conducted ( α = 0.05). Results. The simulation method created realistic motion artifacts compared to real scan reference ( p > 0.05). Motion artifacts were effectively mitigated across testing cases demonstrating generalizability. In simulated scans, LIRS improved from 0.55 ± 0.12–0.75 ± 0.04 and SSIM from 0.87 ± 0.08–0.95 ± 0.03 at bone regions (each p < 0.01). In experimental cadaveric scans, LIRS improved from 0.05 ± 0.01–0.31 ± 0.17 in marker regions and from 0.58 ± 0.19–0.77 ± 0.14 in bone regions (each p < 0.01). Significance. Our simulation method facilitates training DL-assisted motion correction algorithms by providing high-quality training data, effectively supporting 4DCT image quality enhancement.

Abstract Background Ultrasound (US)‐guided hydrodissection is a minimally invasive treatment for cubital tunnel syndrome (CuTS) with promising early results. However, data on patient‐perceived outcomes, durability of relief, and impact on surgical need remain limited. Objective To assess the effectiveness of US‐guided cubital tunnel hydrodissection in improving CuTS symptoms via patient‐centered outcomes. Design Retrospective chart review with cross‐sectional telephone follow‐up. Setting Quaternary medical center multidisciplinary outpatient hand clinic. Participants Seventeen patients (19 arms) with clinical CuTS who received US‐guided hydrodissection from one physician. Interventions Patients were contacted by telephone for cross‐sectional outcome assessment. Main Outcome Measures Patient‐reported improvements in weakness, paresthesias, and/or pain, percent pain relief, symptom improvement duration, adverse events, and Patient Global Impression of Change (PGIC) scores. Results At mean 7 ± 5 month follow‐up, improvement in weakness, paresthesia, and pain was reported in 12 (63%) extremities (95% confidence interval [CI] 41%–85%; p < .001) . Pain relief ≥50% occurred in 12 (63%) and ≥75% in 8 (42%) extremities, with mean duration 4 months. PGIC scores showed 14 (74%; 95% CI 54%–94%; p < .001) at least “minimally improved” and 8 (42%) (95% CI 20%–64%; p < .001) “much improved.” No adverse events occurred. Two patients without improvement underwent surgical decompression with anterior transposition at 1 and 3 months after hydrodissection, achieving 90%–100% pain relief and “much or very much improved” PGIC scores. Of 19 extremities, 7 (37%) were McGowan Grade I and 12 (63%) Grade II; none were Grade III. Grade II extremities showed significantly greater overall symptom relief ( p = .004) and pain relief ≥50% ( p = .004). PGIC scores did not differ significantly between grades (both p > .062). Conclusion US‐guided cubital tunnel hydrodissection was associated with meaningful symptom improvement and no adverse events. Limitations include small sample size, no control group, single operator, and potentially time‐limited relief. The procedure appears safe and a potential nonoperative treatment option.

Background: There is growing evidence that social determinants of health (SDOH) are associated with disparities in access to care and hand and upper extremity health. Quality measures represent an opportunity to evaluate disparities in access and outcomes that can inform improvement interventions. We performed a systematic review of evidence regarding health disparities within hand surgery and aimed to develop suitable quality measures that are clinically important, feasible, usable, and scientifically acceptable. Methods: We performed a systematic review including common hand surgery terms to identify health disparities in hand surgery related to SDOH. Candidate quality measures were constructed based upon evidence from the systematic review. A consortium of 11 US-based hand and upper extremity surgeons completed a modified RAND/UCLA Delphi Appropriateness process to evaluate the importance, feasibility, usability, and scientific acceptability of the candidate quality measures. Panelists rated each measure on a scale of 1 ( definitely not important/feasible/usable/scientifically acceptable ) to 9 ( definitely important/feasible/usable/scientifically acceptable ) in 2 voting rounds separated by a face-to-face discussion. Agreement among panelists and validity were assessed using predetermined criteria. Results: Fourteen candidate quality measures addressing health disparities were identified based on evidence from the systematic review, including time to surgery and emergency department use after hand surgery based on insurance type, clinical outcomes based on social deprivation, among others. All 14 measures were accepted. Conclusions: Fourteen candidate quality measures were identified and accepted based upon consensus to address health disparities in hand surgery, although future investigation will be needed to evaluate their effectiveness.

Abstract Background/Purpose Diagnosing wrist ligament injuries is challenging; early detection and treatment are important to prevent osteoarthritis progression. Interosseous proximity maps, a proxy measure for joint space, can be generated from volumetric imaging data and may provide important information about wrist health. Artificial intelligence (AI) could enhance accuracy of noninvasive diagnosis based on imaging-derived metrics. This work demonstrates feasibility of AI training using synthetic proximity map data generated from finite element models (FEMs). Methods Personalized wrist FEMs for two asymptomatic participants were created from four-dimensional computed tomography-derived anatomic and kinematic data. Monte Carlo sampling varied 22 ligament material properties and simulated 7,500 unique injury scenarios generating 9,000,000 labeled red, green, and blue (RGB) images of interosseous proximity vector fields from FEM-derived motions. Images were associated with 17 descriptive metrics, including gross wrist angles and bone surface pairs, and used to develop mixed-input convolutional neural networks (CNNs). Model performance was evaluated for identifying specific ligament injuries. Results Average area under receiver operating characteristic curve (AUROC) for CNNs was 0.757 across all injury types and kinematics. In a subset with clinically-relevant functional angles, the average AUROC was 0.824. Best-performing individual ligament AUROCs ranged from 0.807 to 0.999. Sensitivities and specificities exceeded 0.99 for some ligament injury simulations under specific wrist angles and bone surface pairs. Conclusion This study demonstrates the feasibility of using synthetic data from FEMs to train AI models for classifying wrist ligament injuries. Proximity-based RGB images may be a relevant biomarker of ligamentous injury.

Purpose To evaluate the clinical, radiographic, and functional outcomes of arthroscopic treatment of scaphoid nonunion in adolescents, using cancellous bone grafting combined with headless compression screw fixation. Methods This retrospective study included adolescent patients treated between 2015 and 2022 with arthroscopically assisted bone grafting and headless compression screw fixation for scaphoid nonunion. Inclusion criteria were nonunion ≥6 months after injury and minimum 12‐month follow‐up; exclusion criteria included degenerative wrist changes. Collected variables included demographic data, injury‐to‐surgery interval, radiographic parameters (including scapholunate angle), time to union, pain scores (visual analog scale), functional outcomes (QuickDASH), and range of motion. Statistical analysis showed significant improvements in visual analog scale and QuickDASH scores ( P < .05). Results Fifteen patients (14 males; mean age 16 years, range 13‐19) met inclusion criteria. The mean follow‐up was 29.2 months. All patients achieved bone union, with an average healing time of 5.7 weeks. Pain (visual analog scale) improved from 2.6 to 0.8, and QuickDASH scores improved from 26.5 to 7.9. The scapholunate angle improved from 60.6° to 46.6°, with stable range of motion postoperatively. No major complications or reoperations occurred. Minimal clinically important difference analysis confirmed meaningful clinical improvement in 93% of patients for pain and 87% for QuickDASH. Conclusions Arthroscopic treatment of scaphoid nonunion in adolescents shows high union rates, improved function, and low morbidity. Level of Evidence Level IV, therapeutic retrospective case series.

Introduction: The biomechanical role of the dorsal scaphotriquetral ligament (DSTL) ligament in scapholunate (SL) stability remains debated. We assessed DSTL contribution using a cadaveric sectioning model. Methods: Twenty-four wrists underwent sequential sectioning: none (phase 0), palmar/proximal scapholunate interosseous ligament (SLIOL) (phase 1), dorsal SLIOL (phase 2), superficial dorsal intercarpal ligament (DICL) (phase 3) and DSTL (phase 4). Under axial loading (60 N; cyclic 60–200 N) and wrist motion, the SL gap and carpal angles, and a CT-derived dorsal instability scaphoid angle (DISA) were measured. Results: Phase 1 produced no significant instability. Dorsal SLIOL sectioning (phase 2) initiated dynamic instability, with increased SL gap and angles under load and dorsal scaphoid translation, but no resting dorsal intercalated segment instability (DISI). Sectioning the superficial DICL fascicle (phase 3) did not add instability. DSTL sectioning (phase 4) produced the largest changes, with marked SL diastasis, increased angles and DISA, and DISI at rest and under load. Conclusion: Dorsal SLIOL sectioning produced load-dependent (dynamic) SL instability, whereas subsequent DSTL sectioning was associated with progression to static instability, supporting the DSTL as an important dorsal restraint. The DISA may provide an additional CT-based measure of dorsal scaphoid subluxation; however, clinical validation is required.

Abstract Background Computational modeling is a tool being deployed for orthopaedic solutions but its use in the hand and wrist remains limited. This work used a model to simulate a clinically relevant provocative scaphoid shift maneuver (SSM) with different levels of scapholunate interosseous ligament (SLIL) injuries to observe the effect on different metrics. Methods A personalized model simulated the full SSM motion cycle from ulnar deviation with extension to radial deviation with flexion informed by the participant’s motion obtained from dynamic computed tomography. Models repeated the SSM under different levels of SLIL injury and reported changes in joint kinematics, contact mechanics, and ligament forces. Results The fully injured model increased scaphoid dorsal translation, flexion, and radial deviation compared to the intact condition and caused a subluxation of the scaphoid. Radioscaphoid contact areas were approximately 200% greater in the fully injured model compared with all others and the fully injured model was the only condition where contact force decreased across the motion cycle. Ligament forces in the intact condition were on average 33.0 N and 54.2 N for the volar and dorsal SLIL, respectively. Lastly, the long radiolunate, an extrinsic stabilizer, had forces that increased following SLIL injury. Conclusions Computational models can successfully recreate clinically observed behaviors of an SSM, including scaphoid subluxation, while providing new insights via quantification of contact mechanics and ligament forces. Contact mechanics metrics may be important for understanding the long-term progression of untreated SLIL injuries to osteoarthritis. Additionally, ligament force metrics may explain the progression of SLIL injuries from volar SLIL to dorsal SLIL and highlight the importance of repairing extrinsic stabilizers of the joint, due to increased force sharing following SLIL injury. This work provides a pathway to future studies investigating the effects of SLIL injury and repair, both acutely and chronically.

Abstract Management of scapholunate advanced collapse (SLAC) wrist arthritis remains challenging in physically high-demand patients with primarily salvage options described for advanced SLAC wrist. Microfracture resurfacing of the scaphoid fossa may be a potential option for this condition. A case of a physically active farmer with advanced SLAC wrist arthritis underwent arthroscopic dorsal capsulodesis of the scapholunate interval, microfracture of the scaphoid fossa chondral defect, and application of cartilage allograft is reported. At 1-year follow-up, there is continued resolution of his wrist pain, and function had improved with increased grip strength and wrist range of motion. Radioscaphoid microfracture and dorsal capsulodesis for SLAC wrist can be a potential dual-pronged reconstructive strategy for the physically high-demand patient that may obviate the need for salvage procedures.