Open research questions in Shoulder Injury and Treatment

What the literature leaves open

• First, the definition of adhesive capsulitis remains unclear, and there is no established consensus regarding the extent of ROM deficit required for the diagnosis [28,29]. The possibility of late-onset stiffness, recurrent instability, or de- generative changes beyond the study period remains unknown.

  Clinical outcomes of arthroscopic stabilization procedures in patients with shoulder dislocation combined with posttraumatic adhesive capsulitis · 2026 · DOI

• Therefore, future research should focus on well-designed, large-scale studies with standardized intervention protocols and longer follow- up durations to establish the long-term effectiveness and clinical applicability of NJF in stroke rehabilitation. Therefore, the long-term effectiveness of NJF remains unclear. Despite these promising results, the evidence is limited by small sample sizes, short intervention periods, and heterogeneity in protocols and outcome measures¹⁷˒²⁹.

  Effects of Neuromuscular Joint Facilitation on Scapular Stability and Upper Limb Function in Stroke: A PRISMA-ScR Guided Scoping Review · 2026 · DOI

• Most of the biomechanical data were contradictory with some studies reporting no differences in the assessed outcomes between the designs, while most reported it to be better in NS head designs.

  Non-spherical head designs in total shoulder arthroplasty: A systematic review of clinical and biomechanical data · 2026 · DOI

• Cognitive–motor dual-task training may improve attentional allocation and motor control, but its role in postoperative ARCR rehabilitation remains unclear.

  Dual-Task Training Improves Shoulder Function and is Associated with Changes in Sensorimotor Network Connectivity After Arthroscopic Rotator Cuff Repair: A Randomized Controlled Trial · 2026 · DOI

• Aims Reverse shoulder arthroplasty (RSA) after prior rotator cuff repair (RCR) is commonly performed for recurrence of pain and arthritic progression; however, the influence of prior RCR timing and technique on outcomes of RSA has not been adequately explored.

  Effect of prior rotator cuff repair technique and timing on clinical outcomes of reverse shoulder arthroplasty · 2026 · DOI

• Several limitations should be acknowledged. The use of a convenience sample drawn from CrossFit gyms in Pretoria may limit the generalisability of findings to other regions or competitive levels. The reliance on self-reported pain and training data may introduce recall bias or underreporting, particularly in environments where training through pain is common. Additionally, the absence of objective clinical measures, such as range-of-motion or strength testing, limits the ability to determine whether reported pain corresponds to measurable functional impairment. The cross-sectional design further precludes causal inference regarding the relationship between training characteristics and shoulder outcomes.

  Prevalence of self-reported shoulder pain and shoulder function among uninjured CrossFit athletes in Pretoria, South Africa · 2026 · DOI

• Future research should employ prospective longitudinal designs to track the progression of shoulder pain and shoulder time. Incorporating objective measures of training load, such as session rating of perceived exertion and wearable monitoring technologies, may provide more precise insight into dose– response is also warranted to determine whether early pain in the presence of to clinically preserved significant shoulder injury. function predicts progression relationships.

  Prevalence of self-reported shoulder pain and shoulder function among uninjured CrossFit athletes in Pretoria, South Africa · 2026 · DOI

• Third, follow-up durations varied widely, with some studies reporting short-term results only, potentially underestimating late complications such as component loosening, progressive gle- noid erosion (especially after HA), or long-term revision risk. Lastly, cost-effective comparisons between TSA and HA were rarely addressed, despite the clear financial implications of prosthesis type and revision burden. However, this reflects the current state of the literature in humeral head AVN, where randomized comparative trials are scarce, and observational comparative cohorts constitute the primary source of available evidence.

  Total shoulder arthroplasty versus hemiarthroplasty for humeral head avascular necrosis: a meta-analysis · 2026 · DOI

• Discussion These findings should be interpreted cautiously, as the exploratory nature of the comparison and the limited evidence base supporting VM preclude definitive conclusions regarding its conceptual or mechanistic superiority compared to standard physiotherapy alone in managing pain, improving shoulder function, and increasing ROM in patients with upper trapezius trigger points associated with SIS.

  Effect of Visceral Manipulation Versus Integrated Neuromuscular Inhibition Technique in Shoulder Impingement Syndrome · 2026 · DOI

• The study population was limited to high school baseball players from a single team, which may restrict the generalizability of our findings to other age groups or competitive levels. In addition, this study did not examine the effects of the participant’s posture (e.g., sitting vs. supine). Furthermore, ulnar nerve displacement was assessed based on predefined visual criteria rather than using direct objective measurements; therefore, the potential influence of observer bias cannot be completely eliminated. Because this study was cross-sectional, it remains unclear whether participants who exhibited changes in ulnar nerve displacement at different shoulder abduction angles would demonstrate symptom provocation in a longitudinal context. The sample size of the present study was limited. Only 6% of the elbows demonstrated a change in displacement status between the two shoulder abduction angles. Based on this discordance rate, an a priori sample size estimation for McNemar’s exact test was performed using G*Power (two-sided α = 0.05, power = 0.80).

  Comparison of ulnar nerve displacement at different shoulder abduction angles in high school baseball players · 2026 · DOI

• This study has several important strengths. With 923 paired observations, it represents one of the largest data- sets investigating visual estimation of a specific joint movement. The use of a cross-classified mixed-effects model allowed appropriate handling of the non-indepen- dent data structure by accounting for clustering at both the rater and video level, thereby providing more robust estimates of systematic bias. In addition, the inclusion of active, functionally relevant movements enhances the clinical applicability of the findings compared to previ- ous studies conducted under passive or highly controlled conditions. Finally, the recruitment of experienced clini- cians from a wide geographical area supports the external relevance of the results. Despite these strengths, several limitations should be considered. First, the analysis was based on a small number of movement recordings from four healthy par- ticipants, which may limit generalisability across different body types, movement patterns, and clinical populations. Second, individual leftacteristics such as gender, body weight, and height were not analysed, although these factors may influence visual estimation accuracy. Third, the study population consisted exclusively of experi- enced physiotherapists, which may limit transferability to less experienced clinicians. In addition, visual esti- mation was performed using two-dimensional video Kenner et al. BMC Musculoskeletal Disorders (2026) 27:514 Page 9 of 10 recordings within an online questionnaire rather than in- person assessment. This may reduce ecological validity compared to clinical settings, where three-dimensional perception and direct interaction are available. Varia- tions in display size and resolution across participants’ devices could not be controlled, although the standard- ized presentation of the questionnaire helped to reduce variability. As each video was rated only once, intra-rater consistency could not be assessed.

  Accuracy of visual estimation of shoulder abduction by expert physiotherapists: a comparative study using 3D motion capture · 2026 · DOI

• Several limitations should be acknowledged. First, although bradycardia and hypotension were analyzed as safety outcomes, most included trials did not report standardized definitions or management strategies, and these events were often presented only as binary outcomes. This limits assessment of severity and warrants cautious clinical interpretation. Second, substantial heterogeneity was observed in several outcomes. Heterogeneity was assessed for all outcomes, and sensitivity analyses were performed where appropriate, with particular attention to studies rated as having “some concerns” in Domain 5 ARTICLE IN PRESS ARTICLE IN PRESS ACCEPTED MANUSCRIPT (selection of the reported result). These studies contributed to increased heterogeneity only in selected outcomes (heart rate after extubation, postoperative hypotension, and pain at 6 hours), while the overall pooled estimates remained largely unchanged, indicating that the main conclusions are robust. Third, variability in dexmedetomidine dosing regimens, administration routes, anesthetic techniques, and outcome timing may have contributed to residual heterogeneity that could not be fully explained. In addition, most included studies were conducted in Asia, which may limit generalizability. Future randomized controlled trials with standardized outcome definitions, detailed reporting of adverse events, and broader geographic representation are needed to further clarify the clinical effects of dexmedetomidine in shoulder arthroscopy.

  Impact of intraoperative dexmedetomidine on postoperative outcomes in shoulder arthroscopy: a systematic review and meta-analysis · 2026 · DOI

• As this is a single case report, the findings should be interpreted within the context of an individual patient and may not be directly generalizable to all cases of Sprengel's deformity. The study evaluated outcomes over a six-week rehabilitation period, and longer-term follow-up could provide additional information regarding the sustainability of functional improvements. Nevertheless, the case offers valuable clinical insights into the potential benefits of a structured physiotherapy rehabilitation program and contributes to the limited evidence available on conservative management of Sprengel's deformity.

  Optimizing Functional Performance in Sprengel’s Shoulder: A Case Report · 2026 · DOI

• Although further investigation is warranted given the limited number of injured catchers, the ex- tended time away from competition necessitated by UCL surgery rehabilitation may allow broader physical recovery, potentially enabling enhanced offensive performance upon return. These find- ings may not be generalizable to baseball players at lower levels of competition.

  Statcast-based evaluation of postoperative performance in Major League Baseball position players following ulnar collateral ligament surgery: a retrospective case-control study · 2026 · DOI

• From a technical standpoint, several considerations are important for successful application of this approach. First, achieving a tension-free primary repair is essential, as excessive tension may compromise both fixation strength and biological healing [5,6]. Second, accurate and individualized passage of suture limbs through the tendon is critical to ensure balanced load distribution. Third, the scaffold should be positioned to adequately cover the footprint without excessive tension, allowing it to function effectively as a secondary load-sharing structure. Conversely, premature incorporation of the scaffold into the primary repair or excessive tightening of sutures may increase stress concentration and negate the potential advantages of the hybrid configuration. Taken together, the key feature of this technique lies in performing a strong primary repair followed by scaffold fixation using the remaining sutures, thereby creating a secondary load-sharing construct rather than a simple covering layer. Given the combined mechanical and biological characteristics of biocomposite scaffolds, this repair-first hybrid augmentation approach may offer a strategy to address both mechanical overload and insufficient biological healing, which are recognized contributors to rotator cuff repair failure. Nevertheless, as this report describes a surgical technique, its clinical effectiveness remains to be established. Further studies, including prospective comparative trials, long-term imaging follow-up and evaluation of structural integrity and functional outcomes, are required to validate the potential benefits of this approach.

  A Hybrid Technique Using a Biocomposite Scaffold for Rotator Cuff Repair: Technical Note · 2026 · DOI

• One limitation of this study is its retrospective design without randomization or blinding, which may introduce the potential for residual confounding despite multivariable adjustment. Follow-up was limited to six months, showing early structural integrity, patient satisfaction and functional outcome but not longer-term outcome. Furthermore, all repairs were performed using a single-row inverted mattress technique, which may limit generalizability to other repair constructs and may have contributed to the high structural failure rate observed in larger tears. The use of musculoskeletal ultrasound rather than magnetic resonance imaging may reduce sensitivity for detecting small or partial defects. However, a standardized imaging protocol and assessment by an experienced musculoskel- etal sonographer were used to enhance reliability. Intraoperative tissue quality grading is inherently subjective, although a standardized grading system was applied. In addition, standardized preoperative MRI-based measures of muscle quality, such as fatty infiltration grading, were not available for the full cohort and therefore could not be incorporated into the analyses. Finally, postoperative satisfaction is a patient-reported outcome and may be influ- enced by baseline expectations and perioperative counseling. Future prospective studies with longer follow-up, standardized imaging protocols, and controlled assessment of patient reported outcomes are needed to confirm the generalizability of our findings.

  Does tear size influence factors associated with early retear, satisfaction, and functional outcomes after arthroscopic rotator cuff repair? · 2026 · DOI

• This study has some limitations. First, the sample size was small and the follow-up period was relatively short, which may limit the ability to fully evaluate the efficacy, safety, and incidence of postoperative complications associated with the 2 surgical ap- proaches. Given the mean follow-up duration of approximately 12 months, the long-term incidence of complications and long- term shoulder function may be underestimated. Second, in the intramedullary nail group, partial incision of the supraspina- tus tendon was required during surgery; however, postopera- tive magnetic resonance imaging or ultrasonography was not performed to assess rotator cuff integrity. Therefore, the inci- dence of iatrogenic rotator cuff injury in this cohort remains unclear. Third, the small number of 4-part fractures may af- fect the generalizability of the findings for this fracture type.

  Outcomes After Minimally Invasive Intramedullary Nail Fixation and Locking Plate Fixation Among Patients With Proximal Humerus Fractures · 2026 · DOI

• Study limitations include a small sample size and short follow-up, which potentially hindered the detection of long-term functional gains or anatomical remodeling via ultrasonography. The absence of a pure placebo group, lack of patient stratification by post-stroke phase, and the etiological heterogeneity of HSP may have influenced out- comes. Additionally, the potential for expectation bias and the lack of a standardized KT protocol limit the generaliza- tion of our findings. Supplementary Information The online version contains supplementary material available at h t t p s : / / d o i . o r g / 1 0 . 1 0 0 7 / s 1 0 1 0 3 - 0 2 6 - 0 4 8 9 0 - 9 . Acknowledgements The authors are grateful to all participants for their valuable contributions to this study and to Dr. Ilkay Dogan for her professional assistance with the statistical analyses. Author contributions Ozlem Altindag: Conceptualization, Writing – Original Draft Preparation. Mazlum Serdar Akaltun: Writing – Origi- nal Draft Preparation. Ali Gur: Conceptualization. Funding The authors declare no potential conflicts of interest and no financial support was received for the research, authorship, and/or pub- lication of this article. Data availability No datasets were generated or analysed during the current study.

  Functional and ultrasonographic evaluation of high intensity laser therapy and Kinesio taping in stroke patients with hemiplegic shoulder pain: a randomized controlled trial · 2026 · DOI

• First, the core limitation of this study is follow-up, with no postoperative shoulder MRI performed to date. The efficacy and safety of the one-stage combined arthroscopic strategy for this rare pathological triad the conclusions have still need to be validated by larger case series and multi-center prospective studies.

  Arthroscopic one-stage management of diffuse shoulder pigmented villonodular synovitis with concomitant full-thickness rotator cuff tear and acromial bone erosion: a rare case report · 2026 · DOI

• This study has several strengths. It is one of the few randomized controlled trials directly comparing ul- trasound-guided HA injection with structured rehabi- litation in the frozen phase of adhesive capsulitis – a therapeutic window where evidence remains limited. The prospective randomized design, standardized treatment protocols, and high follow-up completion rate (87%) enhance the reliability of the findings. Importantly, both interventions produced clinically meaningful improvements in pain, function, and ROM, supporting their roles as effective non-surgical options. p. 8 of 9 HA, in particular, demonstrated an excellent safety profile with no adverse events, underscoring its utility as a non-steroidal alternative for patients who may not be candidates for corticosteroid therapy. Nonetheless, certain limitations should be acknow- ledged, including the modest sample size, lack of blinding, and absence of a sham control. In addition, baseline ROM values were numerically higher in the HA group across most parameters, with active exter- nal rotation demonstrating a statistically significant between-group difference at baseline (p = 0.042). This baseline difference may have contributed to variations in change scores, particularly for external rotation, and should therefore be considered when interpreting the secondary ROM findings. An imbalance in loss to follow-up was observed between groups, with a higher attrition rate in the rehabilitation arm compared with the HA injection arm (5 vs 1 participants). This difference may have introduced potential attrition bias. One possible expl- anation is the greater time commitment required for supervised rehabilitation sessions compared with the shorter treatment course of HA injections. Important- ly, both intention-to-treat and per-protocol analyses yielded comparable results, suggesting that the impact of differential attrition on the primary outcomes was likely limited. These factors should be considered when interpreting the findings. However, the consistency of improvements across multiple outcome measures and the comparable efficacy observed between groups suggest the robustness of the results. Future larger, mul- ticenter trials are warranted to confirm these findings and to determine whether specific patient subgroups may derive differential benefit from either intervention.

  Efficacy of ultrasound-guided intra-articular hyaluronic acid injection in the management of adhesive capsulitis: a randomized controlled trial · 2026 · DOI

• However, several limitations should be considered. Firstly, most included studies had small sample sizes and short fol- low-up periods (≤ 16 weeks), limiting assessment of long- term efficacy. Secondly, considerable heterogeneity existed in HILT parameters and control interventions across studies, which may reflect inadequate consideration of tendinopa- thy stages (e.g., reactive vs. degenerative) as described in Cook’s continuum model [62]. Thirdly, methodological weaknesses such as inadequate blinding and allocation con- cealment were common, potentially introducing bias. Addi- tionally, combining outcomes measured with different tools may have increased heterogeneity. Although subgroup anal- ysis could address this, limited studies and data precluded a thorough analysis. Future large-scale, multicenter RCTs with longer follow-up are needed to optimize HILT param- eters, standardize protocols, and evaluate efficacy across patient subtypes.

  Effectiveness of high-intensity laser therapy for tendinopathy: a systematic review and meta-analysis of randomised controlled trials · 2026 · DOI

• Although there is evidence of an association between CSS and musculoskeletal problems, no studies have focused on the association between CSS and RCT.

  Central sensitization syndrome in patients with rotator cuff tear: prevalence and associated factors · 2023 · DOI

• Most researchers have examined the outcomes of surgical management and found high levels of satisfaction and return of shoulder function, but the ability to return to sport varied widely, with 20% to 94% of patients returning to their sport after surgical or nonoperative management.

  National Athletic Trainers' Association Position Statement: Evaluation, Management, and Outcomes of and Return-to- Play Criteria for Overhead Athletes With Superior Labral Anterior-Posterior Injuries · 2018 · DOI

• Research encourages the use of exercise prescription for the management of a RC tendinopathy, however the ideal method of delivery (group setting versus one-on-one) remains uncertain.

  The Effectiveness of an Upper Extremity Neuromuscular Training Program on the Shoulder Function of Military Members With a Rotator Cuff Tendinopathy: A Pilot Randomized Controlled Trial · 2018 · DOI

• CONTEXT: Little is known about pitching performance or lack of it among Major League Baseball (MLB) pitchers who undergo operative treatment of rotator cuff tears.

  Performance After Rotator Cuff Tear and Operative Treatment: A Case-Control Study of Major League Baseball Pitchers · 2011 · DOI

Most-cited papers in Shoulder Injury and Treatment

• Fatty Infiltration and Atrophy of the Rotator Cuff do not Improve after Rotator Cuff Repair and Correlate with Poor Functional Outcome · The American Journal of Sports Medicine · 2007 · 846 citations
• Treatment of Chronic Elbow Tendinosis with Buffered Platelet-Rich Plasma · The American Journal of Sports Medicine · 2006 · 645 citations
• Redefining “Critical” Bone Loss in Shoulder Instability · The American Journal of Sports Medicine · 2015 · 636 citations
• Factors Affecting Rotator Cuff Healing After Arthroscopic Repair · The American Journal of Sports Medicine · 2011 · 367 citations
• A Clinical Method for Identifying Scapular Dyskinesis, Part 1: Reliability · Journal of Athletic Training · 2009 · 350 citations
• Electromyographic analysis of the glenohumeral muscles during a baseball rehabilitation program · The American Journal of Sports Medicine · 1991 · 313 citations
• Effect of an Anterior Glenoid Defect on Anterior Shoulder Stability · The American Journal of Sports Medicine · 2009 · 309 citations
• Arthroscopic Release of the Long Head of the Biceps Tendon · The American Journal of Sports Medicine · 2004 · 240 citations
• Location of the Glenoid Defect in Shoulders with Recurrent Anterior Dislocation · The American Journal of Sports Medicine · 2005 · 220 citations
• Comparison of the Clinical Outcomes of Single- and Double-Row Repairs in Rotator Cuff Tears · The American Journal of Sports Medicine · 2008 · 199 citations

Most recent work

• Superior Capsule Reconstruction With Thicker Human Dermal Allograft Leads to Lower Lateral‐Sided Graft Tears and Better Functional Outcomes · Arthroscopy The Journal of Arthroscopic and Related Surgery · 2026
• The Use of Allograft or Xenograft Augmentation in Rotator Cuff Repair Is Cost‐Effective Particularly With Allograft · Arthroscopy · 2026
• In Vivo 3‐Dimensional Glenohumeral Joint Geometry Based Upon Magnetic Resonance Imaging and Computed Tomography Analysis Shows Deeper, Thicker, and Taller Glenoid Labrum Morphology at 12 O’Clock Position in Healthy Young Adults · Arthroscopy The Journal of Arthroscopic and Related Surgery · 2026
• Patient-specific instrumentation vs. a free-hand technique for glenoid baseplate and peripheral screw placement in reverse total shoulder arthroplasty using the Exactech implant system: a multicenter randomized controlled trial · Journal of Shoulder and Elbow Surgery · 2026
• Pre-operative methicillin-resistant Staphylococcus aureus colonization increases the risk of 90-day medical and 2-year implant-related complications following primary total shoulder arthroplasty: a propensity-matched analysis · Journal of Shoulder and Elbow Arthroplasty · 2026
• A Novel Ultrasound-Guided Injection Strategy for Rapid Functional Recovery in Frozen Shoulder: A Multicenter Randomized Trial · The American Journal of Sports Medicine · 2026
• Beach Chair Versus Lateral Decubitus Surgical Positioning for Arthroscopic Shoulder Stabilization Surgery: What Does The Evidence Say? · Current Reviews in Musculoskeletal Medicine · 2026
• Restoring Glenoid Concavity: Angled Bone Blocks Provide Biomechanically Superior Function and Restore Glenohumeral Forces Over Flat Constructs in Glenoid Augmentation · The American Journal of Sports Medicine · 2026
• Duloxetine Improves Early Clinical Outcomes Including Range of Motion, Functional Scores, Pain, and Psychological Distress After Arthroscopic Rotator Cuff Repair in Patients With Anxiety or Depression: Prospective Randomized Controlled Trial · The American Journal of Sports Medicine · 2026
• Making Sense of Shoulder Exercise: Measuring the Accuracy of an Artificial Intelligence Model to Classify Shoulder Exercise via Wearable Sensors Among People With and Without Rotator Cuff Tendinopathy · European Journal of Sport Science · 2026

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