Shoulder Dislocation: Assessment of Lesions, Trajectories and Outcomes (SALTO)

Traumatic anterior shoulder dislocation is a common injury, particularly among young and active individuals. Recurrence after a first-time anterior dislocation is frequent and varies substantially depending on age, activity level, and structural injury. Established risk factors include young age, male sex, hyperlaxity, participation in contact or overhead sports and concomitant bony or soft tissue injury. Despite the high recurrence risk in selected patient groups, most first-time dislocators are treated non-operatively in current Norwegian practice.

Subtle bony defects may be underdiagnosed on plain radiographs. Approximately one-third of patients sustain a bony Bankart lesion, and more than 70% present with a Hill-Sachs lesion. The size and location of the Hill-Sachs lesion, as well as its on-track/off-track classification, have implications for treatment strategy. CT with three-dimensional reconstruction is considered the most reliable method for assessing glenoid and humeral bone loss, while MRI enables detailed evaluation of associated soft tissue injuries, including labral and capsuloligamentous lesions.

The SALTO study is a prospective observational cohort including all eligible patients aged ≥16 years presenting with first-time anterior shoulder dislocation at a defined urban emergency clinic. The study will systematically assess bone loss using CT and characterize soft tissue injuries using MRI. Patients will be followed longitudinally with clinical data and patient-reported outcome measures to evaluate recurrence, shoulder function, and long-term shoulder function.

By correlating imaging findings with recurrent instability and long-term outcomes, the study aims to improve risk stratification after first-time anterior shoulder dislocation and identify patients who may benefit from early surgical intervention.

Primary outcomes

• Epidemiology of first time shoulder dislocations in Oslo, Norway [From enrollment through completion of inclusion, an average of 2 years]: Incidence of first-time anterior shoulder dislocations in the Oslo region and prevalence of bipolar bone loss and soft tissue injuries assessed by CT and MRI
• Prevalence of bipolar bone loss assessed by CT [Baseline]: Presence and extent of bipolar bone loss (glenoid bone loss and Hill-Sachs lesion) assessed using computed tomography (CT)
• Prevalence of soft tissue injury assessed by MRI [Baseline]: Presence of soft tissue injuries (e.g., Bankart lesion, ALPSA lesion, HAGL lesion, SLAP lesion, rotator cuff injury) assessed using magnetic resonance imaging (MRI).

Secondary outcomes

• Recurrence of instability after first time shoulder dislocation [From enrollment, data analysis and questionnaire after 3 and 12 months, 2, 5 and 10 years]: Prevalence of recurrent instability after first time shoulder dislocation, defined as glenohumeral redislocation requiring reduction. To identify clinical, demographic, and imaging-related risk factors, especially bipolar bone loss, for recurrent instability.
• Patient reported outcomes and shoulder function (WOSI) [3 months, 1 year, 2 year, 5 year and 10 years after first time shoulder dislocation]: Patient-reported shoulder function measured using the Western Ontario Shoulder Instability Index (WOSI) score. The WOSI score ranges from 0 to 2100, where lower scores indicate better shoulder function and quality of life. Scores may be converted to a percentage scale ranging from 0-100%, where higher scores indicate better shoulder function and quality of life.
• Glenohumeral osteoarthritis after first time shoulder dislocation [10 years after first time shoulder dislocation]: To evaluate radiographic signs of glenohumeral osteoarthritis at 10-year follow-up and examine their association with recurrence and baseline bone loss
• Health-related quality of life (EQ-5D-5L) [3 months, 1, 2, 5 years and 10 years]: Health-related quality of life measured using the EuroQol 5-Dimension 5-Level questionnaire (EQ-5D-5L). Responses from the five dimensions will be converted into an EQ-5D-5L index score using the Norwegian value set. The index score ranges from less than 0 (health states worse than death) to 1 (perfect health), where higher scores indicate better health-related quality of life.
• Shoulder pain intensity [3 months, 1 year, 2 years, 5 years and 10 years]: Shoulder pain intensity measured using the Visual Analogue Scale (VAS) ranging from 0 to 10, where higher scores indicate greater pain intensity.
• Shoulder function (Rowe Score) [3 months and 10 years]: To measure general shoulder function included pain, stability, range and function using the Rowe Score, ranging from 0 to 100, where higher scores indicate better shoulder stability and function.
• Return to sport [3 months, 1 year, 2, 5 years and 10 years]: Return to sport after first-time shoulder dislocation assessed using a patient questionnaire evaluating whether the participant has returned to sport and at what level compared with pre-injury activity.
• EQ-VAS [3 months, 1,2,5 and 10 years]: EQ-VAS is a self-reported health status measured using the EQ-5D visual analogue scale ranging from 0 (worst imaginable health) to 100 (best imaginable health).

Sex: All, ages: 16 Years to any

Inclusion Criteria

* Age ≥16 years
* Diagnosis of first-time traumatic anterior shoulder dislocation
* Resident in the Oslo region who presents to Oslo Accident and Emergency Outpatient Clinic for treatment or follow-up within two weeks after initial injury
* Ability to provide informed consent

Exclusion Criteria

* Previous shoulder dislocation requiring reduction (Patients uncertain about prior dislocation are excluded)
* Age < 16 years
* Chronic substance abuse affecting compliance
* Inability to understand Norwegian or English
* Adult not able to provide consent or severe medical or psychiatric condition precluding follow-up

• Wasserstein DN, Sheth U, Colbenson K, Henry PD, Chahal J, Dwyer T, Kuhn JE. The True Recurrence Rate and Factors Predicting Recurrent Instability After Nonsurgical Management of Traumatic Primary Anterior Shoulder Dislocation: A Systematic Review. Arthroscopy. 2016 Dec;32(12):2616-2625. doi: 10.1016/j.arthro.2016.05.039. Epub 2016 Jul 31. PMID 27487737
• Rutgers C, Verweij LPE, Priester-Vink S, van Deurzen DFP, Maas M, van den Bekerom MPJ. Recurrence in traumatic anterior shoulder dislocations increases the prevalence of Hill-Sachs and Bankart lesions: a systematic review and meta-analysis. Knee Surg Sports Traumatol Arthrosc. 2022 Jun;30(6):2130-2140. doi: 10.1007/s00167-021-06847-7. Epub 2022 Jan 6. PMID 34988633
• Olds M, Ellis R, Donaldson K, Parmar P, Kersten P. Risk factors which predispose first-time traumatic anterior shoulder dislocations to recurrent instability in adults: a systematic review and meta-analysis. Br J Sports Med. 2015 Jul;49(14):913-22. doi: 10.1136/bjsports-2014-094342. Epub 2015 Apr 21. PMID 25900943
• Nakagawa S, Iuchi R, Hanai H, Hirose T, Mae T. The Development Process of Bipolar Bone Defects From Primary to Recurrent Instability in Shoulders With Traumatic Anterior Instability. Am J Sports Med. 2019 Mar;47(3):695-703. doi: 10.1177/0363546518819471. Epub 2019 Jan 23. PMID 30673556
• Liavaag S, Svenningsen S, Reikeras O, Enger M, Fjalestad T, Pripp AH, Brox JI. The epidemiology of shoulder dislocations in Oslo. Scand J Med Sci Sports. 2011 Dec;21(6):e334-40. doi: 10.1111/j.1600-0838.2011.01300.x. Epub 2011 Apr 21. PMID 21507063
• Hurley ET, Manjunath AK, Bloom DA, Pauzenberger L, Mullett H, Alaia MJ, Strauss EJ. Arthroscopic Bankart Repair Versus Conservative Management for First-Time Traumatic Anterior Shoulder Instability: A Systematic Review and Meta-analysis. Arthroscopy. 2020 Sep;36(9):2526-2532. doi: 10.1016/j.arthro.2020.04.046. Epub 2020 May 8. PMID 32389771
• Enger M, Skjaker SA, Nordsletten L, Pripp AH, Melhuus K, Moosmayer S, Brox JI. Sports-related acute shoulder injuries in an urban population. BMJ Open Sport Exerc Med. 2019 Aug 12;5(1):e000551. doi: 10.1136/bmjsem-2019-000551. eCollection 2019. PMID 31548901
• Dickens JF, Slaven SE, Cameron KL, Pickett AM, Posner M, Campbell SE, Owens BD. Prospective Evaluation of Glenoid Bone Loss After First-time and Recurrent Anterior Glenohumeral Instability Events. Am J Sports Med. 2019 Apr;47(5):1082-1089. doi: 10.1177/0363546519831286. PMID 30943084
• Di Giacomo G, Itoi E, Burkhart SS. Evolving concept of bipolar bone loss and the Hill-Sachs lesion: from "engaging/non-engaging" lesion to "on-track/off-track" lesion. Arthroscopy. 2014 Jan;30(1):90-8. doi: 10.1016/j.arthro.2013.10.004. PMID 24384275
• Delage Royle A, Balg F, Bouliane MJ, Canet-Silvestri F, Garant-Saine L, Sheps DM, Lapner P, Rouleau DM. Indication for Computed Tomography Scan in Shoulder Instability: Sensitivity and Specificity of Standard Radiographs to Predict Bone Defects After Traumatic Anterior Glenohumeral Instability. Orthop J Sports Med. 2017 Oct 30;5(10):2325967117733660. doi: 10.1177/2325967117733660. eCollection 2017 Oct. PMID 29119123
• Belk JW, Wharton BR, Houck DA, Bravman JT, Kraeutler MJ, Mayer B, Noonan TJ, Seidl AJ, Frank RM, McCarty EC. Shoulder Stabilization Versus Immobilization for First-Time Anterior Shoulder Dislocation: A Systematic Review and Meta-analysis of Level 1 Randomized Controlled Trials. Am J Sports Med. 2023 May;51(6):1634-1643. doi: 10.1177/03635465211065403. Epub 2022 Feb 11. PMID 35148222