Ameya V. Belamkar

Spinal cord stimulation (SCS) is a widely used neuromodulatory therapy for chronic neuropathic pain, yet the cellular and molecular mechanisms underlying its clinical efficacy remain incompletely understood. This review synthesizes current literature on the neurophysiology of pain transmission and the mechanistic basis of major SCS paradigms (tonic, high-frequency, burst, and closed-loop stimulation), highlighting how each modality engages distinct dorsal horn circuits, glial and inflammatory pathways, as well as supraspinal networks involved in the affective dimension of pain. Particular attention is given to the evoked compound action potential (ECAP) as an emerging electrophysiological biomarker that enables real-time, feedback-guided stimulation and offers insight into the biophysical determinants of dorsal column activation. We also examine preclinical and clinical evidence linking SCS to modulation of central sensitization, neuroinflammatory signaling, and autonomic regulation, while identifying persistent gaps in mechanistic understanding. Finally, we discuss future directions, including AI-assisted, personalized SCS programming and expanding indications beyond classical neuropathic pain, underscoring the need for multimodal experimental approaches to more precisely define how SCS achieves analgesia.

Patient‐reported outcome measures (PROMs) are vital tools to evaluate patient health status. Although a plethora of validated tools are available to evaluate common pathologies in knee arthroscopy, agreement on the most appropriate metrics for different populations and procedures has not been reached. Selection of an appropriate PROM requires consideration of its validity, clinically significant outcomes, and ceiling effects. The validation of an outcome measure encompasses three distinct psychometric properties: validity, reliability, and responsiveness, and the demonstration of appropriate psychometric validity lends credibility of the results derived from its use in clinical and research settings. Notably, statistical significance does not always translate to clinical significance. Minimal clinically important difference, patient‐acceptable symptomatic state, and substantial clinical benefit are clinically significant outcomes that represent the spectrum of meaningful clinical impact for a patient. However, these metrics are population‐ and study‐specific and should be interpreted at the individual level. Ceiling effects prevent differentiation between patients scoring at the upper extreme of the PROM and are an important limitation of several instruments used to evaluate patients undergoing orthopaedic sports medicine knee procedures. The purpose of this narrative review is to provide a comprehensive overview of popular PROMs used in the evaluation of orthopaedic sports medicine knee procedures and review their applicability to commonly encountered pathologies. The scoring, interpretation, and psychometric properties of each PROM are presented along with examples of minimal clinically important difference, substantial clinical benefit, and patient‐acceptable symptomatic state values found for the specific cohorts in previous studies. Level of Evidence: Level V, expert opinion.

Background: The short-term efficacy of hip arthroscopy as a salvage procedure for acetabular dysplasia and concomitant femoroacetabular impingement syndrome (FAIS) in patients who are not candidates for periacetabular osteotomy remains unclear. Purposes: We sought to compare 2-year patient-reported outcome measures (PROMs) after hip arthroscopy for FAIS (control group) versus FAIS with acetabular dysplasia (dysplasia group) in patients over 40 years of age and/or with mild osteoarthritis (OA). We also sought to measure the rate of subsequent total hip arthroplasty (THA) on the same operative hip. Methods: We retrospectively reviewed prospectively collected data from patients who underwent hip arthroscopy for FAIS by a single surgeon between January 2021 and December 2024. Fourteen patients in the dysplasia group (mean lateral center-edge angle <23°, range 12-32; anterior center edge angle 20°, range 8-25; age 41.5 ± 11.4 years) and 140 controls (mean age 36.0 ± 12.5 years) were included. We analyzed the European Quality of Life – 5 Dimensions-5 Levels, Mental Health Inventory-5, International Hip Outcome Tool-12 (iHOT-12), Physical Function Short Form of the Hip Disability and Osteoarthritis Outcome Score (HOOS-PS), University of California at Los Angeles (UCLA) Activity Scale, Adult Single Item Measure physical activity, Patient-Acceptable Symptoms State (PASS) single item, and subsequent THA on the same operative hip. Results: The dysplasia group demonstrated lower PASS rates, iHOT-12 scores, and HOOS-PS scores compared to controls. THA conversion was higher in the dysplasia group than in the control group (50% vs 5%). In multivariate analysis, dysplasia negatively predicted all outcomes. Intraoperatively identified high-grade cartilage defects predicted THA conversion, but none of the PROMs. Conclusion: This retrospective case-control study suggests that hip arthroscopy alone for FAIS with acetabular dysplasia in patients over 40 years and/or with mild OA may increase the odds of clinical failure compared to arthroscopy for FAIS without dysplasia. High-grade cartilage defects identified intraoperatively were independent risk factors for conversion to THA regardless of dysplasia status. Level of Evidence: Level III: retrospective case-control study.

Background: Hinged prostheses in revision total knee arthroplasty (rTKA) are typically reserved for cases of severe bone loss and/or ligamentous insufficiency. The increased constraint of the hinge (i.e., fewer degrees of freedom) is critical for providing sufficient stabilization in these complex cases, but also results in higher forces throughout the construct, which may increase the risk of re-revision due to aseptic loosening. This study compared patient-reported outcome measures (PROMs) in case-control matched cohorts of hinged versus non-hinged rTKAs. Methods: A retrospective review of 1,477 rTKAs was performed. After exclusions, 62 hinged and 730 non-hinged implants were available for matching. A total of 55 aseptic hinged rTKAs were case-control matched to 55 aseptic non-hinged rTKAs based on demographics of age, sex, BMI, and ASA-PS classification. The primary outcomes of the study were PROMs and reoperation rates. A P-value of 0.05 was considered statistically significant. Results: The two matched groups did not differ by demographics or comorbidities (P≥0.225); except for an increased prevalence of lumbar spine disease in the non-hinged group (26% versus 11%, P=0.048), which did not affect PROMs (P≥0.100). In addition, no differences in PROMs were observed between groups at any time interval (P≥0.105). Furthermore, there was a slightly higher incidence of all-cause reoperation due to patella/extensor mechanism (11% versus 5%) and all-cause septic reoperation (9% versus 2%) in the hinged group, but these differences did not reach statistical significance (P≥0.190). Potential Impact: This study demonstrated that PROMs were not significantly different for patients who received a hinged rTKA compared to a non-hinged rTKA, suggesting that patients may benefit from the increased stability provided by the hinge. The association with extensor mechanism complications in the hinged rTKA group likely reflects the selection bias inherent in this study design, as more complex cases were more likely to receive hinged devices.

Case: A 33-year-old woman with a 1-year history of right gluteal and pelvic pain due to entrapment of the pudendal nerve by a bifurcate piriformis muscle underwent piriformis tenotomy, pudendal neurolysis, and sciatic neurolysis by an open posterolateral hip approach. At 32-week follow-up, the patient was free of deep gluteal pain and all pudendal neuralgia symptoms. Conclusion: Pudendal nerve entrapment by the piriformis is an uncommon cause of pudendal neuralgia that can be effectively treated with surgical intervention. We demonstrate an open posterolateral hip approach may provide significant pain relief and satisfactory improvements in patient-reported outcomes in management of this pathology.

Diabetic retinopathy (DR) is a chronic complication of diabetes and a leading cause of blindness in the industrialized world. Traditional risk factors, such as glycemic control and duration of diabetes, are unable to explain why some individuals remain protected while others progress to a more severe form of the disease. Differences are also observed in DR heritability as well as the response to anti-vascular endothelial growth factor (VEGF) treatment. This review discusses various aspects of genetics in DR to shed light on DR pathogenesis and treatment. First, we discuss the global burden of DR followed by a discussion on disease pathogenesis as well as the role genetics plays in the prevalence and progression of DR. Subsequently, we provide a review of studies related to DR’s genetic contribution, such as candidate gene studies, linkage studies, and genome-wide association studies (GWAS) as well as other clinical and meta-analysis studies that have identified putative candidate genes. With the advent of newer cutting-edge technologies, identifying the genetic components in DR has played an important role in understanding DR incidence, progression, and response to treatment, thereby developing newer therapeutic targets and therapies.