Glenoid augmentation for subcritical bone loss: a narrative review.

Background and Objective: Anterior shoulder instability can be debilitating for young, active individuals, and increasing magnitudes of glenoid bone loss (GBL) predisposes patients to recurrent instability and increases the likelihood of failure of soft-tissue only repairs. It is widely accepted that GBL >25% should be treated with a glenoid bone grafting procedure. However, consensus is lacking on the optimal management in the setting of subcritical GBL, typically classified as >13.5%. This article reviews the pathoanatomy relevant to anterior shoulder instability and subcritical GBL, while highlighting existing evidence regarding open augmentation procedures in comparison to other treatment options for this subpopulation. Methods: A narrative review of the current literature was conducted focusing on subcritical GBL in anterior glenoid stabilization procedures, including review of forward citation and reference lists of selected articles. Key Content and Findings: Computed tomography (CT) is the modality of choice for obtaining precise measurements of subcritical GBL, defined as <13.5%, using the best-fit circle method. There is debate surrounding the optimal surgical management of subcritical GBL. Arthroscopic Bankart repair (ABR) remains the predominate surgery performed for primary anterior shoulder instability, while glenoid augmentation and open Bankart repair continue to be used sparingly in the United States. Historically, the Latarjet procedure was considered for substantial glenoid defects, but the illumination of subcritical GBL has expanded its indications. Arthroscopic, soft tissue-only repairs with the addition of remplissage, has been shown to have similar 2-year outcomes to the Latarjet in patients with >15% GBL, which has been limited in the study of subcritical GBL. Additionally, utilization of distal tibial allograft and local autograft is becoming increasingly prevalent. However, again, with limited prospective studies in the subcritical GBL population. Conclusions: There is no consensus regarding the optimal treatment approach to recurrent shoulder instability in the setting of subcritical GBL. Conversely, there is a growing agreement that isolated ABR is likely inadequate and subcritical GBL should prompt consideration of a more robust operation. To this end, interest in glenoid bone augmentation continues to grow as a reliable technique for recreating the native architecture and restoring glenohumeral stability are developed.

Arthroscopic Management of Arthrofibrosis After Hemiarthroplasty for Proximal Humerus Fracture Dislocation.

Poor functional outcomes after hemiarthroplasty for proximal humerus fractures are common, yet revision surgery is relatively rare. Arthroscopic treatment for postoperative stiffness can be considered in the setting of functional limits to glenohumeral range of motion impacting activities of daily living after adequate conservative treatment with physical therapy and in the setting of healed, well-positioned tuberosities and humeral components. This Technical Note illustrates a stepwise approach to an arthroscopic lysis of adhesions and capsular release for the treatment of arthrofibrosis of the shoulder. The advantages of this technique include an alternative approach to entering the glenohumeral joint under direct subacromial visualization and a 2-posterior portal approach to the inferior and anteroinferior capsule, which can be challenging to achieve in the setting of severe postsurgical arthrofibrosis.

Minimal Important Clinical Difference Values Are Not Uniformly Valid in the Active Duty Military Population Recovering from Shoulder Surgery.

BACKGROUND: There are multiple methods for calculating the minimal clinically important difference (MCID) threshold, and previous reports highlight heterogeneity and limitations of anchor-based and distribution-based analyses. The Warfighter Readiness Survey assesses the perception of a military population's fitness to deploy and may be used as a functional index in anchor-based MCID calculations. The purpose of the current study in a physically demanding population undergoing shoulder surgery was to compare the yields of two different anchor-based methods of calculating MCID for a battery of PROMs, a standard receiver operator curve (ROC) -based MCIDs and baseline-adjusted ROC MCIDs. METHODS: All service members enrolled prospectively in a multicenter database with prior shoulder surgery that completed pre- and postoperative PROMs at a minimum of 12 months were included. The PROMs battery included Single Assessment Numeric Evaluation (SANE), American Shoulder and Elbow Surgeons score (ASES), Patient Reported Outcome Management Information System (PROMIS) Physical Function (PF), PROMIS Pain Interference (PI), and the Warfighter Readiness survey. Standard anchor-based and baseline-adjusted ROC MCIDs were employed to determine if the calculated MCIDs were both statistically and theoretically valid (95% confidence interval either completely negative or positive). RESULTS: There were 117 patients (136 operations) identified, comprised of 83% males with a mean age of 35.7 ± 10.4 years and 47% arthroscopic labral repair/capsulorrhaphy. Using the standard, anchor-based ROC MCID calculation, the area under the curve (AUC) for SANE, ASES, PROMIS PF, and PROMIS PI were greater than 0.5 (statistically valid). For ASES, PROMIS PF, and PROMIS PI, the calculated MCID 95% CI all crossed 0 (theoretically invalid). Using the baseline-adjusted ROC MCID calculation, the MCID estimates for SANE, ASES, and PROMIS PI were both statistically and theoretically valid if the baseline score was less than 70.5, 69, and 65.7. CONCLUSION: When MCIDs were calculated and anchored to the results of standard, anchor-based MCID, a standard ROC analysis did not yield statistically or theoretically valid results across a battery of PROMs commonly used to assess outcomes after shoulder surgery in the active duty military population. Conversely, a baseline-adjusted ROC method was more effective at discerning changes across a battery of PROMs among the same cohort.

Novel 3D MRI-Based Volumetric Assessment of Rotator Cuff Musculature Demonstrates Stronger Correlation with Preoperative Functional Status When Compared to the Goutallier Grading Scheme.

BACKGROUND: The Goutallier classification (GC) is used to assess fatty atrophy in rotator cuff (RC) tears, yet limitations exist. A battery of 3D-magnetic resonance imaging (MRI) volumetric scores (VS) was developed to provide comprehensive characterization of RC pathology. The purposes of this study were to: (1) Describe the correlation between GC and VS for supraspinatus changes in RC tears, (2) Characterize the chronicity of RC tears using the battery of 12 VS measurements, and (3) Compare GC and VS to determine which method most closely corresponds with preoperative patient reported outcome measures (PROMs). METHODS: Preoperative shoulder MRIs were reviewed after arthroscopic RC repair. Preoperative GC stage and Patient-Reported Outcomes Measurement Information System (PROMIS) physical function (PF) and pain interference (PI) scores were collected. The battery of VS included fat infiltration (FIS), muscle size (MSS) and relative volume contribution (RCS) for each RC muscle. Backwards linear regression was performed to compare GC stage with preoperative PROMIS PF/PI to determine which VS measurement most closely correlated with preoperative PROMs. RESULTS: Eighty-two patients underwent RC repair (mean age 55±8.2 years, 63% male, 68% GC stage ≤1). In evaluation of the supraspinatus, there was a moderate positive correlation between GC and FIS (r = 0.459, p < 0.001); strong negative correlations were observed between MSS (r = -0.800, p < 0.001) and RCS (r = -0.745, p < 0.001) when compared to GC. A negligible linear correlation was observed between GC and preoperative PROMIS PF (r = -0.106, p = 0.343) and PI (r = -0.071, p = 0.528). On multivariate analysis, subscapularis MSS (beta > 0, p = 0.064) was a positive predictor, and subscapularis FIS (beta < 0, p = 0.137), teres minor MSS (beta < 0, p = 0.141) and FIS (beta < 0, p = 0.070) were negative predictors of preoperative PF (r = 0.343, p = 0.044); while supraspinatus MSS (beta > 0, p = 0.009) and FIS (beta > 0, p = 0.073), teres minor FIS (beta > 0, p = 0.072) and subscapularis FIS (beta > 0, p = 0.065) were positive predictors of preoperative PI (r = 0.410, p = 0.006). CONCLUSION: Although gold standard in evaluation of RC pathology, GC demonstrated negligible correlation with preoperative functional disability. Alternatively, a battery of 3D VS showed strong correlation with GC through a quantitative, comprehensive evaluation of the RC unit including several moderate predictors of preoperative functional disability.

Knee Joint Preservation in Tactical Athletes: A Comprehensive Approach Based upon Lesion Location and Restoration of the Osteochondral Unit.

The unique physical demands of tactical athletes put immense stress on the knee joint, making these individuals susceptible to injury. In order to ensure operational readiness, management options must restore and preserve the native architecture and minimize downtime, while optimizing functionality. Osteochondral lesions (OCL) of the knee have long been acknowledged as significant sources of knee pain and functional deficits. The management of OCL is predicated on certain injury characteristics, including lesion location and the extent of subchondral disease. Techniques such as marrow stimulation, allograft and autologous chondrocyte implantation are examined in detail, with a focus on their application and suitability in tactical athlete populations. Moreover, the restoration of the osteochondral unit (OCU) is highlighted as a central aspect of knee joint preservation. The discussion encompasses the biomechanical considerations and outcomes associated with various cartilage restoration techniques. Factors influencing procedure selection, including lesion size, location, and patient-specific variables, are thoroughly examined. Additionally, the review underscores the critical role of post-operative rehabilitation and conditioning programs in optimizing outcomes. Strengthening the surrounding musculature, enhancing joint stability, and refining movement patterns are paramount in facilitating the successful integration of preservation procedures. This narrative review aims to provide a comprehensive resource for surgeons, engineers, and sports medicine practitioners engaged in the care of tactical athletes and the field of cartilage restoration. The integration of advanced preservation techniques and tailored rehabilitation protocols offers a promising avenue for sustaining knee joint health and function in this demanding population.

The Psychology of ACL Injury, Treatment, and Recovery: Current Concepts and Future Directions.

CONTEXT: Interest in the relationship between psychology and the outcomes of anterior cruciate ligament (ACL) reconstruction (ACLR) continues to grow as variable rates of return to preinjury level of activity continue to be observed. EVIDENCE ACQUISITION: Articles were collected from peer-reviewed sources available on PubMed using a combination of search terms, including psychology, resilience, mental health, recovery, and anterior cruciate ligament reconstruction. Further evaluation of the included bibliographies were used to expand the evidence. STUDY DESIGN: Clinical review. LEVEL OF EVIDENCE: Level 4. RESULTS: General mental health and wellbeing, in addition to a host of unique psychological traits (self-efficacy, resilience, psychological readiness and distress, pain catastrophizing, locus of control, and kinesiophobia) have been demonstrated convincingly to affect treatment outcomes. Moreover, compelling evidence suggests that a number of these traits may be modifiable. Although the effect of resilience on outcomes of orthopaedic surgical procedures has been studied extensively, there is very limited information linking this unique psychological trait to the outcomes of ACLR. Similarly, the available information related to other parameters, such as pain catastrophizing, is limited with respect to the existence of adequately sized cohorts capable of accommodating more rigorous and compelling analyses. A better understanding of the specific mechanisms through which psychological traits influence outcomes can inform future interventions intended to improve rates of return to preinjury level of activity after ACLR. CONCLUSION: The impact of psychology on patients' responses to ACL injury and treatment represents a promising avenue for improving low rates of return to preinjury activity levels among certain cohorts. Future research into these areas should focus on specific effects of targeted interventions on known, modifiable risk factors that commonly contribute to suboptimal clinical outcomes. STRENGTH-OF-RECOMMENDATION TAXONOMY (SORT): B.

Patient Resilience Does Not Conclusively Affect Clinical Outcomes Associated With Arthroscopic Surgery but Substantial Limitations of the Literature Exist.

Purpose: To determine whether low resilience is predictive of worse patient-reported outcomes (PROs) or diminished improvements in clinical outcomes after joint preserving and arthroscopic surgery. Methods: A comprehensive search of PubMed, Medline, Embase, and Science Direct was performed on September 28, 2022, for studies investigating the relationship between resilience and PROs after arthroscopic surgery in accordance with the Preferred Reported Items for Systematic Reviews and Meta-analyses guidelines. Results: Nine articles (level II-IV studies) were included in the final analysis. A total of 887 patients (54% male, average age 45 years) underwent arthroscopic surgery, including general knee (n = 3 studies), ACLR-only knee (n = 1 study), rotator cuff repair (n = 4 studies), and hip (n = 1 study). The Brief Resilience Scale was the most common instrument measuring resilience in 7 of 9 studies (78%). Five of 9 studies (56%) stratified patients based on high, normal, or low resilience cohorts, and these stratification threshold values differed between studies. Only 4 of 9 studies (44%) measured PROs both before and after surgery. Three of 9 studies (33%) reported rates of return to activity, with 2 studies (22%) noting high resilience to be associated with a higher likelihood of return to sport/duty, specifically after knee arthroscopy. However, significant associations between resilience and functional outcomes were not consistently observed, nor was resilience consistently observed to be predictive of subjects' capacity to return to a preinjury level of function. Conclusions: Patient resilience is inconsistently demonstrated to affect clinical outcomes associated with joint preserving and arthroscopic surgery. However, substantial limitations in the existing literature including underpowered sample sizes, lack of standardization in stratifying patients based on pretreatment resilience, and inconsistent collection of PROs throughout the continuum of care, diminish the strength of most conclusions that have been drawn. Level of Evidence: Level IV, systematic review of level II-IV studies.

Treatment of Tendon Injuries in the Servicemember Population across the Spectrum of Pathology: From Exosomes to Bioinductive Scaffolds.

Tendon injuries in military servicemembers are one of the most commonly treated nonbattle musculoskeletal injuries (NBMSKIs). Commonly the result of demanding physical training, repetitive loading, and frequent exposures to austere conditions, tendon injuries represent a conspicuous threat to operational readiness. Tendon healing involves a complex sequence between stages of inflammation, proliferation, and remodeling cycles, but the regenerated tissue can be biomechanically inferior to the native tendon. Chemical and mechanical signaling pathways aid tendon healing by employing growth factors, cytokines, and inflammatory responses. Exosome-based therapy, particularly using adipose-derived stem cells (ASCs), offers a prominent cell-free treatment, promoting tendon repair and altering mRNA expression. However, each of these approaches is not without limitations. Future advances in tendon tissue engineering involving magnetic stimulation and gene therapy offer non-invasive, targeted approaches for improved tissue engineering. Ongoing research aims to translate these therapies into effective clinical solutions capable of maximizing operational readiness and warfighter lethality.

Editorial Commentary: Biocomposite Implant Combined With Local Human Recombinant Parathyroid Hormone Enhances the Histological Quality and Biomechanical Strength of Rotator Cuff Repairs.

Rates of rotator cuff repair retear remain unacceptably high and are frequently the source of diminished shoulder function and patient dissatisfaction. Endocrinopathies have been implicated in these processes. Parathyroid hormone (PTH) activates chondrogenesis and angiogenesis at the enthesis and prevents fatty infiltration and atrophy in rotator cuff musculature. These facts have spurred interest in the therapeutic benefits of PTH as a means to enhance tendon healing and strengthen the bone in and around tendon repairs. New research demonstrates that recombinant human PTH delivered locally through a process of coupling it to a bioengineered scaffold "sheath" may be beneficial. The growth factor, encased within polycaprolactone (PCL), is slowly released as the PCL degrades to extend drug delivery time. The augmentation of rotator cuff repairs with this biocomposite material improves short-term structural tissue integrity and promotes the formation of more organized and stronger tendon-to-bone interface in a rabbit model.

An Update on Orthobiologics: Cautious Optimism.

Orthobiologics are rapidly growing in use given their potential to augment healing for multiple musculoskeletal conditions. Orthobiologics consist of a variety of treatments including platelet-rich plasma and stem cells that provide conceptual appeal in providing local delivery of growth factors and inflammation modulation. The lack of standardization in nomenclature and applications within the literature has led to a paucity of high-quality evidence to support their frequent use. The purpose of this review was to describe the current landscape of orthobiologics and the most recent evidence regarding their use.

Subacromial Balloon Spacer for the Massive Irreparable Cuff Tear.

PURPOSE OF REVIEW: The purpose of the review is to provide an updated overview of a relatively novel but controversial surgical device (InSpace subacromial balloon, Stryker, Kalamazoo, MI) that can be readily incorporated into the armamentarium of the shoulder surgeon. The authors review the critical clinical and surgical decision-making aspects of InSpace. A recommended surgical technique and rehabilitation protocol are outlined. The authors present a nuanced view of the balloon spacer in the continuum of care of the irreparable rotator cuff tear. RECENT FINDINGS: Within the last year, two Level I clinical trials have been published, and the data from these studies offer conflicting evidence regarding the utility of the subacromial balloon spacer. The current review contrasts these two recent studies and offers a framework by which the available evidence can be practically understood with respect to clinical decision-making. The literature currently supports a limited indication for use of InSpace: the elderly, low-demand patient with preserved active range of motion with an operatively irreparable, posterosuperior rotator cuff tear with an intact subscapularis. The InSpace subacromial balloon spacer is a simple device that can yield substantial improvements in clinical outcomes among a subset of patients with irreparable rotator cuff tears. InSpace is not a panacea for the complex, irreparable rotator cuff tear. Individualized decision-making is necessary in this diverse and challening patient population.

Editorial Commentary: Decreased Superior Capsular Reconstruction Postoperative Graft Volume Is More Common in Patients With Advanced Rotator Cuff Arthropathy and Is Associated With Inferior Outcome: Cause or Effect?

Recent research has investigated the impact of graft condition on the outcomes of shoulder superior capsular reconstruction for irreparable rotator cuff tears. A decreased lateral graft volume compared with the medial graft volume is more common in patients with rotator cuff arthropathy and is associated with inferior clinical outcomes. This would suggest that aside from simply failing at the suture-graft junction, grafts with thinner lateral segments may exhibit diminished biomechanical strength over time. This may explain, in part, the discrepancy in outcomes between thinned grafts and grafts with preservation of tissue thickness. However, a significant association is also shown between grafts with lateral thinning and factors that portend worse clinical outcomes, including a higher Hamada grade, larger anteroposterior distance of the graft spanning the greater tuberosity, increased fatty infiltration in the infraspinatus and subscapularis muscles, and higher rate of subscapularis retears postoperatively. This would suggest that reductions in graft volume may be a product of worse initial pathology, which in and of itself may explain the worse postoperative outcomes. Thus, it remains unclear whether the findings represent cause or effect.

Predictors of Return to Activity at 2 Years After Anterior Cruciate Ligament Reconstruction Among Patients With High Preinjury Marx Activity Scores: A MOON Prospective Cohort Study.

BACKGROUND: Predictors of return to activity after anterior cruciate ligament reconstruction (ACLR) among patients with relatively high preinjury activity levels remain poorly understood. PURPOSE/HYPOTHESIS: The purpose of this study was to identify predictors of return to preinjury levels of activity after ACLR, defined as achieving a Marx activity score within 2 points of the preinjury value, among patients with Marx activity scores of 12 to 16 who had been prospectively enrolled in the Multicenter Orthopaedic Outcomes Network (MOON) cohort. We hypothesized that age, sex, preinjury activity level, meniscal injuries and/or procedures, and concurrent articular cartilage injuries would predict return to preinjury activity levels at 2 years after ACLR. STUDY DESIGN: Cohort study; Level of evidence, 2. METHODS: All unilateral ACLR procedures from 2002 to 2008 performed in patients enrolled in the MOON, with preinjury Marx activity scores ranging from 12 to 16, were evaluated with a specific focus on return to preinjury activity levels at 2 years postoperatively. Return to activity was defined as a Marx activity score within 2 points of the preinjury value. The proportion of patients able to return to preinjury activity levels was calculated, and multivariable modeling was performed to identify risk factors for patients' inability to return to preinjury activity levels. RESULTS: A total of 1188 patients were included in the final analysis. The median preinjury Marx activity score was 16 (interquartile range, 12-16). Overall, 466 patients (39.2%) were able to return to preinjury levels of activity, and 722 patients (60.8%) were not able to return to preinjury levels of activity. Female sex, smoking at the time of ACLR, fewer years of education, lower 36-Item Short Form Health Survey Mental Component Summary scores, and higher preinjury Marx activity scores were predictive of patients' inability to return to preinjury activity levels. Graft type, revision ACLR, the presence of medial and/or lateral meniscal injuries, a history of meniscal surgery, the presence of articular cartilage injuries, a history of articular cartilage treatment, and the presence of high-grade knee laxity were not predictive of a patient's ability to return to preinjury activity level. CONCLUSION: At 2 years after ACLR, most patients with high preinjury Marx activity scores did not return to their preinjury level of activity. The higher the preinjury Marx activity score that a patient reported at the time of enrollment, the less likely he/she was able to return to preinjury activity level. Smoking and lower mental health at the time of ACLR were the only modifiable risk factors in this cohort that predicted an inability to return to preinjury activity levels. Continued effort and investigation are required to maximize functional recovery after ACLR in patients with high preinjury levels of activity.

Objective analysis of partial three-dimensional rotator cuff muscle volume and fat infiltration across ages and sex from clinical MRI scans.

Objective analysis of rotator cuff (RC) atrophy and fatty infiltration (FI) from clinical MRI is limited by qualitative measures and variation in scapular coverage. The goals of this study were to: develop/evaluate a method to quantify RC muscle size, atrophy, and FI from clinical MRIs (with typical lateral only coverage) and then quantify the effects of age and sex on RC muscle. To develop the method, 47 full scapula coverage CTs with matching clinical MRIs were used to: correct for variation in scan capture, and ensure impactful information of the RC is measured. Utilizing this methodology and automated artificial intelligence, 170 healthy clinical shoulder MRIs of varying age and sex were segmented, and each RC muscle's size, relative contribution, and FI as a function of scapula location were quantified. A two-way ANOVA was used to examine the effect of age and sex on RC musculature. The analysis revealed significant (p < 0.05): decreases in size of the supraspinatus, teres minor, and subscapularis with age; decreased supraspinatus and increased infraspinatus relative contribution with age; and increased FI in the infraspinatus with age and in females. This study demonstrated that clinically obtained MRIs can be utilized for automatic 3D analysis of the RC. This method is not susceptible to coverage variation or patient size. Application of methodology in a healthy population revealed differences in RC musculature across ages and FI level between sexes. This large database can be used to reference expected muscle characteristics as a function of scapula location and could eventually be used in conjunction with the proposed methodology for analysis in patient populations.

Editorial Commentary: A Biphasic (Calcified and Demineralized), Cancellous, Interpositional Allograft Augmenting Rotator Cuff Repair in an Ovine Model Does Not Show Harmful Inflammation or Foreign Body Reaction.

To improve the outcomes of arthroscopic rotator cuff (RC) repair, it is important to achieve tendon-to-bone healing at the repair site. Healed repairs are more likely to restore shoulder strength and lead to higher magnitudes of satisfaction. Patches or grafts that can be either secured to the bursal surface of the RC or interposed between the RC tendon and greater tuberosity at the time of repair have been described as adjuncts to RC repair. A cancellous, biphasic allograft tissue composed of 2 layers (calcified to promote osseointegration and demineralized to support soft-tissue ingrowth) has been shown to be safe in an ovine model, without a harmful inflammatory or foreign body response. Human trials may be a reasonable next step.

Psychological Readiness to Return to Sport: Fear of Reinjury Is the Leading Reason for Failure to Return to Competitive Sport and Is Modifiable.

Many of our patients are athletes, and an ultimate goal is to help these athletes return to their preinjury level of activity or sport. Generally, we focus on patients' injuries and treatments, but there are modifiable factors that can improve patient outcomes independent of surgical technique. A factor frequently ignored is psychological readiness to return to sport. In patients including athletes, particularly teenagers, chronic, clinical depression is a prevalent and pathologic condition. In addition, in nondepressed patients (or in patients who are situationally depressed because of injury), the ability to deal with stressors may still govern clinical outcomes. Specific psychological traits of significance have been identified and defined, including self-efficacy; locus of control; resilience; catastrophizing; kinesiophobia; and fear of reinjury. (Fear of reinjury is the leading reason for failure to return to competitive sport, reduced activity levels after sports injury, and greater reinjury rates.) The traits may overlap and may be modifiable. Thus, like strength and functional testing, we should evaluate for signs or symptoms of depression, and we should measure psychological readiness to return to sport. With awareness, we can intervene or refer as indicated. Psychological readiness to return to sport represents an underexamined domain in which we can help our patients achieve best outcomes.

Documented Contact Allergy Impacts Risk for Surgical Adhesive-Associated Contact Dermatitis after Shoulder Arthroplasty.

Purpose: The purpose of this study is to report on the incidence and risk factors for allergic contact dermatitis (ACD) in patients who received Prineo after total shoulder arthroplasty (SA). Methods: A retrospective case-control study was conducted to investigate patients who experienced ACD after having SA by a single surgeon during a defined period when Prineo was routinely used as an adjunct to wound closure. Known risk factors for ACD (e.g., history of contact dermatitis, smoking) were analyzed for association development of Prineo-associated ACD using Fisher exact and Wilcoxon rank sum tests. Results: From June 2019 through July 2021, 236 consecutive patients were identified as having Prineo applied after SA. Nine cases of Prineo-ACD (3.8%) were documented, whereas 227 patients were unaffected. In all 9 affected patients, the complication was identified and treated without compromising the outcome of the SA. Previous allergy to medical adhesives was a statistically significant risk factor for Prineo-associated ACD in this series (P = .01). The odds of having Prineo-associated ACD among those with adhesive or contact allergy was 38.5 times that of their nonallergic counterparts in a multivariate model. Conclusions: Prineo adhesive ACD had an incidence of 3.8% in this study, and a history of adhesive or contact allergy was highly associated with its development. Level of Evidence: Level III, case-control study.

Quadriceps Dysfunction Following Joint Preservation Surgery: A Review of the Pathophysiologic Basis and Mitigation Strategies.

PURPOSE OF REVIEW: To characterize quadriceps muscle dysfunction associated with knee joint preservation surgery, with a focus on its pathophysiology and promising approaches to mitigate its impact on clinical outcomes. RECENT FINDINGS: Quadriceps dysfunction (QD) associated with knee joint preservation surgery results from a complex interplay of signaling, related to changes within the joint and from those involving the overlying muscular envelope. Despite intensive rehabilitation regimens, QD may persist for many months postoperatively and negatively impact clinical outcomes associated with various surgical procedures. These facts underscore the need for continued investigation into the potential detrimental effects of regional anesthetic and intraoperative tourniquet use on postoperative quadriceps function, with an outward focus on innovation within the field of postoperative rehabilitation. Neuromuscular stimulation, nutritional supplementation, cryotherapy, blood flow restriction (BFR), and open-chain exercises are all potential additions to postoperative regimens. There is compelling literature to suggest that these modalities are efficacious and may diminish the magnitude and duration of postoperative QD. A clear understanding of QD, with respect to its pathophysiology, should guide perioperative treatment and rehabilitation strategies and influence ongoing rehabilitation-based research and innovation. Moreover, clinicians must appreciate the magnitude of QD's effect on diminished clinical outcomes, risk for re-injury and patients' ability (or inability) to return to pre-injury level of activity following knee joint preservation procedures.

Editorial Commentary: High Variability Exists Among Different Techniques for Measuring Glenoid Bone Loss.

Glenoid bone loss is a predominant factor in determining proper surgical management for glenohumeral instability. Precise measurements of glenoid (and humeral) bone defects are fundamental, and millimeters matter. Three-dimensional computed tomography scans may provide the highest interobserver reliability for making these measurements. Yet, because imprecision in the range of millimeters is observed with even the most precise glenoid bone loss measurement techniques, it could be a mistake to over-rely, let alone solely rely, on glenoid bone loss measurement as the primary determinant for selecting one surgical procedure over another. Surgeons must measure glenoid bone loss but also thoughtfully consider patient age, associated soft-tissue injuries, and activity level, including throwing and participation in collision sports. When choosing the proper surgical procedure for a shoulder instability patient, we should not focus on only one variably measured parameter but, instead, on a comprehensive assessment of the patient.

A Deep Learning Algorithm for Automatic 3D Segmentation of Rotator Cuff Muscle and Fat from Clinical MRI Scans.

The authors aimed to develop and validate an automated artificial intelligence (AI) algorithm for three-dimensional (3D) segmentation of all four rotator cuff (RC) muscles to quantify intramuscular fat infiltration (FI) and individual muscle volume. The dataset included retrospectively collected RC MRI scans in 232 patients (63 with normal RCs, 169 with RC tears). A two-stage AI model was developed to segment all RC muscles and their FI in each stage. For comparison, single-stage and Otsu filtering models were created. Using the two-stage model, segmentation performance demonstrated high Dice scores (mean, 0.92 ± 0.14 [SD]), low volume errors (mean, 5.72% ± 9.23), and low FI errors (mean, 1.54% ± 2.79) when validated in 30 scans. There was a significant correlation between the 3D FI in the RC tear scans with a Goutallier grade (ρ = 0.53, P < .001) and FI found from a single two-dimensional (2D) section (all muscles, ρ > 0.70; P < .001). However, Bland-Altman analysis of the 3D compared with the 2D analyses of FI demonstrated a proportional bias (all muscles, P < .001). Compared with Goutallier classification or single-image quantification, the AI method allowed for more variability in images and led to objective separate quantifications of muscle volume and FI in all RC muscles. Keywords: Rotator Cuff, Artificial Intelligence, Segmentation, Fat Infiltration, Muscle Volume, MRI, Shoulder Supplemental material is available for this article. © RSNA, 2023.