Multidirectional instability of the shoulder: biomechanics, clinical presentation, and treatment strategies

Assessment and diagnosis of non-traumatic shoulder instability: A scoping review

Background

Given its complexity, there is no consensus regarding the assessment of non-traumatic shoulder instability (NTSI) to this day. We, therefore, conducted a scoping review to map the existing white and grey literature regarding diagnostic and assessment tools for the NTSI population.

Method

We followed the Arksey and O'Malley five-stage guideline for the conduct of scoping reviews and searched through 12 electronic databases for English-language articles and reviews from 2000 to 2024 related to NTSI's diagnosis and assessment tools.

Results

Among the 3426 identified studies, 58 were included (describing 59 different interventions). Case-control studies (43.1%, 25/58) and narrative reviews (34.5%, 20/58) were the most prevalent. Diagnostic imaging was the most studied intervention (35.6%, 21/59). Twenty-seven studies specified a direction of instability, of which 59% (16/27) were multidirectional instability. Non-traumatic shoulder instability often affects young individuals, with complex symptoms, including neuromotor deficits, muscular imbalances and kinematic alterations, involving psycho-behavioural and somatosensory components.

Discussion

Non-traumatic shoulder instability's aetiologies and clinical manifestations are multifactorial. The prevalence and incidence of this dysfunction are probably underestimated. Clinical history is crucial to retrace a complex and chronic dysfunction. The use of orthopaedic shoulder tests and the routine use of imaging currently appear to have limited relevance as a first-line approach.

The efficacy of conservative management of micro-traumatic posterior shoulder instability

Background

Microtraumatic posterior shoulder instability (PSI) is characterized by symptomatic posterior translation of the glenohumeral joint. A common etiology is a gradual overload of glenohumeral joint structures. The recommend initial treatment for microtraumatic PSI is rehabilitation; however, the evidence to support this recommendation is limited. The aim of this study is to investigate the patient- reported outcome measures and return to sport success of participants with microtraumatic PSI who participate in a posterior instability rehabilitation program.

Methods

In the single-group study design, 24 shoulders in 22 sporting participants (17 male, 5 females; mean age, 21.1 years, standard deviation 10.1 years) diagnosed with microtraumatic PSI undertook the Watson Posterior Instability Program (WIP-p) over 24 weeks. Outcome measures included the Melbourne Instability Shoulder Score and Western Ontario Shoulder Instability Index at baseline, 6, 12, and 24 weeks. Failure of conservative management and time to return to sport was measured. Treatment effects were determined using linear mixed models, with 95% confidence intervals. Significance was set at 0.05.

Results

After 24 weeks of the WIP-p, participants had significant improvements at 12 (effect size or standardized mean difference (SMD): 1.1, P < .001) and 24 weeks (SMD: 1.8, P < .001) on the Western Ontario Shoulder Instability Index and significant improvements at 6 (SMD; 0.74, P = .036), 12 (SMD: 0.41, P = .007) and 24 weeks (SMD: 1.7, P < .001) on the Melbourne Instability Shoulder Score. For return to sport, 20 of the 22 (90.1%) participants returned to full activity at the 24-week time point, while two went on to have reconstructive surgery.

Discussion and Conclusion

The WIP-p resulted in a high level of return to sport and significantly improved functional outcomes in patients with microtraumatic PSI. A small proportion of sporting participations with microtraumatic PSI may fail conservative rehabilitation and require surgical consideration.

Glenohumeral Joint Volume Measurement in Patients with Shoulder Instability: A 3D Volumetric Magnetic Resonance Arthrographic Study

Background and Objectives: This study aimed to compare capsular volume in patients with shoulder instability to that in control subjects without instability using magnetic resonance (MR) arthrography. The objective was to develop a reliable screening method with which to assess shoulder volume. Materials and Methods: In 21 patients with atraumatic shoulder instability and 21 controls, thin-slice 3D volumetric MR arthrography sequences were obtained. MR arthrography images were uploaded to 3D reconstruction, and 3D images were generated. From the 3D reconstructed images, volumetric measurements of rotator interval (RI), anterior and posterior capsular (AC, PC) recesses, biceps tendon sheath (BS), axillary recess (AR), and total glenohumeral joint (TGJ) were performed. Individuals with any extra-articular contrast leakage were also recorded. Results: A retrospective study analyzed a patient group of 21 individuals with shoulder instability (mean age 29.52 ± 12.83 years) and a control group of 21 individuals without instability (mean age 35.71 ± 12.77 years). No statistically significant differences were identified between the groups with regard to age, gender, or side distribution. The mean total joint volume was significantly higher in the instability group (29.85 ± 6.40 cm3) compared to the control group (23.15 ± 3.48 cm3, p = 0.0001). Additionally, the mean volumes of the RI, AC, PC, BS, and AR were all significantly greater in the patient group compared to the control group. Conclusions: 3D volumetric MR arthrographic measurements of the shoulder joint capacity can provide valuable insights for clinical follow-up and guide surgical treatment decisions in cases of atraumatic shoulder instability.

Does glenoid bone loss accompany posterior shoulder instability with only labral tear? A magnetic resonance imaging-based study

BACKGROUND

The primary aim of this study was to investigate bone loss in the glenoid with magnetic resonance imaging in posterior shoulder instability with only a labral tear.

METHODS

A total of 76 patients operated on because of posterior and anteroposterior shoulder instability only with a labral tear between 2006 and 2019 (n = 40 and n = 36, respectively) were included in this study. The instability type, a presence of an additional superior labrum anteroposterior (SLAP) lesion, the number of dislocations, and the magnetic resonance imaging-based measurements (the glenoid diameter and the bone defect size in the glenoid, the Hill-Sachs lesion [HSL] and the reverse HSL [rHSL] length, the angle and the arc length of HSL and rHSL, and the humerus head diameter and its area) were analyzed.

RESULTS

The size of the anterior glenoid defect, the rHSL measurements (length, angle, and arc length), and the ratio of the anterior glenoid defect size to the glenoid diameter were significantly higher for anteroposterior instability (P < .01) cases. There was no significant difference (P = .49, .64, and .82, respectively) for the presence of an additional SLAP pathology, the glenoid diameter, the posterior glenoid defect, and the ratio of the posterior glenoid defect size to the glenoid diameter in posterior and anteroposterior instability groups. The increased number of dislocations was associated with increased rHSL length and total arc length (P = .04 and .03, respectively). An additional SLAP lesion in posterior shoulder instabilities was not associated with the bone defect size (P = .29).

CONCLUSION

Although the posterior shoulder instability with only a labral tear is likely to cause a bone defect, we have shown that the instability is not expected to be caused by the bone defect. Therefore, this study points out that only soft tissue repair without considering the bone defect could be promising in this patient group.

Posterior Shoulder Instability in Tennis Players: Aetiology, Classification, Assessment and Management

Background

Micro-traumatic posterior shoulder instability (PSI) is an often missed and misdiagnosed pathology presenting in tennis players. The aetiology of micro-traumatic PSI in tennis players is multifactorial, including congenital factors, loss of strength and motor control, and sport-specific repetitive microtrauma. Repetitive forces placed on the dominant shoulder, particularly combinations of flexion, horizontal adduction, and internal rotation contribute to the microtrauma. These positions are characteristic for kick serves, backhand volleys, and the follow-through phase of forehands and serves. The aim of this clinical commentary is to present an overview of the aetiology, classification, clinical presentation, and treatment of micro-traumatic PSI, with a particular focus on tennis players.

Level of Evidence

5.

Multidirectional instability of the shoulder: surgical techniques and clinical outcome

Multidirectional instability of the shoulder has a complex pathoanatomy. It is characterized by a redundant glenohumeral capsule and increased joint volume. Subtle clinical presentation, unclear trauma history and multifactorial etiology poseses a great challenge for orthopedic surgeons in terms of diagnosis. Generally accepted therapeutic approach is conservative and the majority of patients achieve good results with rehabilitation. In patients who are symptomatic despite appropriate rehabilitation, surgical intervention may be considered. Good results have been obtained with open inferior capsular surgery, which has historically been performed in these patients. In recent years, advanced arthroscopic techniques have taken place in this field, and similar results compared to open surgery have been obtained with the less-invasive arthroscopic capsular plication procedure.

Advances in the Non-Operative Management of Multidirectional Instability of the Glenohumeral Joint

Multidirectional instability (MDI) of the glenohumeral joint refers to symptomatic subluxations or dislocations in more than one direction. The aetiology of MDI is multifactorial, which makes the classification of this condition challenging. A shoulder rehabilitation program is the initial recommended treatment for MDI, however available rehabilitation programs have varying levels of evidence to support their effectiveness. In 2016, we published the details of an evidence-based program for MDI that has been evaluated for efficacy in two single-group studies and a randomised controlled trial. In 2017, we published a clinical commentary on the aetiology, classification, and treatment of this condition. The aim of this paper is to provide an update on the components of these publications with a particular focus on new advances in the non-operative management of this condition.

Rehabilitation for atraumatic shoulder instability in circus arts performers: delivery via telehealth

BACKGROUND

The Watson Instability Program (WIP1) is current best evidence for conservative management of atraumatic shoulder instability, but it is unknown if this program can be effectively delivered via tele-consultation. The purpose of this longitudinal pre-post intervention study was to determine the effects of the WIP1 on patient-reported outcome measures, scapular position, shoulder strength, and handstand stability in student circus performers with atraumatic shoulder instability when delivered via tele-consultation.

METHODS

Student circus performers aged between 15 and 35 years from the National Institute of Circus Arts were recruited. A 12-week shoulder exercise program was delivered via tele-consultation during the Melbourne, Australia COVID-19 (coronavirus disease 2019) lockdown. The primary outcome measures were the Western Ontario Shoulder Instability Index score and the Melbourne Instability Shoulder Scale score. Secondary outcomes measures included the Orebro Musculoskeletal Pain Questionnaire, the Tampa Scale for Kinesiophobia, and physical assessment measures including strength via handheld dynamometry, scapular position using an inclinometer, and handstand stability via center-of-pressure fluctuation. Patient-reported outcomes were collected at baseline and 6-week, 12-week, 6-month, and 9-month time points, and physical outcomes were measured at baseline and 9-month time points. A repeated-measures mixed model (with effect sizes [ESs] and 95% confidence intervals [CIs]) was used to analyze patient-reported outcomes, handstand data, strength, and scapular measures. Significance was set at P < .05.

RESULTS

Twenty-three student circus arts performers completed the study. Significant improvements were found in both Western Ontario Shoulder Instability Index scores (effect size [ES], 0.79 [95% CI, 0.31-1.33] at 6 weeks; ES, 1.08 [95% CI, 0.55-1.6] at 12 weeks; ES, 1.17 [95% CI, 0.62-1.78] at 6 months; and ES, 1.31 [95% CI, 0.74-1.95] at 9 months; P < .001) and Melbourne Instability Shoulder Scale scores (ES, 0.70 [95% CI, 0.22-1.22] at 6 weeks; ES, 0.83 [95% CI, 0.34-1.37] at 3 months; ES, 0.98 [95% CI, 0.46-1.54] at 6 months; and ES, 0.98 [95% CI, 0.43-1.50] at 9 months; P < .001), as well as Orebro Musculoskeletal Pain Questionnaire scores at all follow-up time points. The Tampa Scale for Kinesiophobia scores reached significance at 6 weeks and 12 weeks. Following rehabilitation, we found statistically significant increases in shoulder strength in all positions tested and increased scapular upward rotation measured at end-of-range abduction, as well as during loaded external rotation. The affected arm showed greater instability than the unaffected arm with a significant intervention effect on the affected arm showing a greater consistent anterior-posterior movement pattern.

CONCLUSION

In a group of circus performers with atraumatic shoulder instability, treatment with the WIP1 via telehealth resulted in clinically and statistically significant improvements in shoulder symptoms and function.

Management of atraumatic shoulder instability in physiotherapy (MASIP): a survey of physiotherapy practice

BACKGROUND

The impact of atraumatic shoulder instability (ASI) on patients can be extensive, its management complex, with a biopsychosocial approach recommended. Currently how physiotherapists manage ASI is unknown or the extent to which current clinical practice aligns with existing evidence. At the time of this study no national guidelines or consensus to direct practice existed.

METHODS

A cross-sectional electronic survey was distributed between July-September 2018, targeting UK-based physiotherapists managing shoulder pathology. Respondents were invited to describe their management of ASI, and rate their awareness and utilisation of various treatment techniques on a Likert-scale; median and interquartile ranges were calculated. Free text survey items were analysed using quantitative content analysis (QCA) to identify codes and categories. Means and percentages were calculated to summarise QCA and descriptive data.

RESULTS

Valid survey responses were analysed (n = 135). Respondents had between 2 and 39 years of physiotherapy experience (mean = 13.9 years); the majority (71.1 %) reported that ASI made up < 10 % of their caseload. Only 22.9 % (n = 31/135) of respondents reported feeling 'very confident' in managing ASI; the majority feeling 'somewhat confident' (70.4 %, n = 95/135) or 'not confident' (6.7 %, n = 9/135). The majority of respondents (59.3 %) used an ASI classification system, > 90 % citing the Stanmore Classification. Physiotherapists adapted their management according to clinical presentation, responding to differing biopsychosocial needs of the patient scenario. Most respondents (> 80 %) did not use a protocol to guide their management. Exercise was the most utilised management approach for ASI, followed by education; novel treatment strategies, including cortical rehabilitation, were also reported.

CONCLUSION

Findings indicate physiotherapists utilise a wide range of treatment strategies and respond to biopsychosocial cues when managing patients with ASI. The majority reported not being very confident in managing this condition, however only a minority use rehabilitation protocols to support their management. Some interventions that respondents reported using lacked evidence to support their use in ASI management and further research regarding effectiveness is required. Guidelines have been published since this survey; the impact of these will need evaluating to determine their effectiveness in the future.

Hip arthroscopy and T-shaped capsular plication for the treatment of borderline dysplasia: a minimum 2-year follow-up

PURPOSE

The aim of the study was to evaluate the clinical outcomes of patients treated arthroscopically for symptomatic borderline dysplasia of the hip (BHD) with a T-shaped capsular plication, with a minimum follow-up of 24 months.

METHODS

Twenty-seven patients who had undergone hip arthroscopy and T-shaped capsular plication for symptomatic BHD were included in the study. All patients were clinically evaluated prior to surgery (T₀) and at two consecutive follow-ups (T₁: 12 ± 1.2 months; T₂: 52.0 ± 23.2 months) using the visual analogue scale (VAS) pain score, the Hip Outcome Score in activities of daily living (HOS-ADL) and sport-specific subscale (HOS-SSS), the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) and Short Form-12 in its physical (PCS) and mental component scores (MCS). We also evaluated the presence of correlations and analysed the possible differences between subgroups.

RESULTS

We found a significant difference for HOS-ADL, HOS-SSS, VAS and WOMAC with the Friedman test for repeated measures through time points (p < 0.0001), but not for MCS. All clinical scores reported a significant improvement compared to the previous time point (p < 0.05), with the exception of HOS-SSS, for which p = 0.2570 between T₁ and T₂. The body mass index was positively correlated with preoperative VAS (R = 0.42857; p = 0.0257) and negatively correlated with PCS at T₀ (R = - 0.40999; p = 0.0337) and with PCS (R = - 0.40491; p = 0.0362), MCS (R = - 0.45939; p = 0.0159) and WOMAC (R = - 0.40573; p = 0.0216) at T₂. No complications were reported in our cohort.

CONCLUSIONS

The results of the current study confirm that patients with intra-articular hip pathology and concomitant BHD (LCEA 20°-25°) can benefit from arthroscopic treatment and that T-shaped capsular plication is one of the available options. Orthopaedic surgeons specialising in hip arthroscopy should consider arthroscopy for the treatment of symptomatic BHD for stabilising and strengthening the joint. Future studies should focus on finding out which type of patients can benefit most from this procedure.

LEVEL OF EVIDENCE IV

Prospective Case Series.

Open Capsulorrhaphy for Recurrent Multidirectional Instability of the Shoulder

Background

The management of multidirectional instability (MDI) of the shoulder remains challenging, especially in athletes who participate in sports and may require multiple surgical procedures to achieve shoulder stabilization. Open or arthroscopic procedures can be performed to address shoulder MDI.

Indications

Open capsulorrhaphy is preferred in patients with underlying tissue hyperlaxity and who had 1 or more, previously failed, arthroscopic shoulder stabilization procedures.

Technique Description

With the patient in the beach-chair position (45°), tissue dissection is performed to the level of subscapularis tendon via the deltopectoral approach. The subscapularis tenotomy is performed in an L-shaped fashion, and the subscapularis tendon is tagged with multiple sutures and mobilized. Careful separation of the subscapularis tendon from the underlying capsular tissue is critical. Capsulotomy is performed, consisting of a vertical limb and an inferior limb that extends to the 5 o'clock position on the humeral neck (right shoulder). After evaluating the integrity of the labrum, the capsule is shifted superiorly and laterally, and repaired using 4 to 5 suture anchors. The redundant capsule is excised, and the subscapularis tendon is repaired in a side-to-side fashion, augmented by transosseous equivalent repair using the capsular sutures.

Results

Adequate shoulder stabilization was achieved following open capsulorrhaphy in a young female athlete with tissue hyperlaxity and history of a previously failed arthroscopic soft tissue stabilization surgery of the shoulder. The athlete returned to sport at 6 months postoperatively and did not experience recurrent shoulder instability episodes at midterm follow-up.

Discussion/Conclusion

Based on the existing literature, 82% to 97% of patients who underwent open capsulorrhaphy for MDI had no recurrent shoulder instability episodes at midterm follow-up. One study reported 64% return-to-sport rate following open capsulorrhaphy in 15 adolescent athletes with Ehlers-Danlos syndrome, but more research is necessary to better define the indications and outcomes of this procedure in physically active patients.

The glenohumeral ligaments: Superior, middle, and inferior: Anatomy, biomechanics, injury, and diagnosis

The three glenohumeral ligaments (superior, middle, and inferior) are discrete thickenings of the glenohumeral joint capsule and are critical to shoulder stability and function. Injuries to this area are a cause of significant musculoskeletal morbidity. A literature search was performed by a review of PubMed, Google Scholar, and OVID for all relevant articles published up until 2020. This study highlights the anatomy, biomechanical function, and injury patterns of the glenohumeral ligaments, which may be relevant to clinical presentation and diagnosis. A detailed understanding of the normal anatomy and biomechanics is a necessary prerequisite to understanding the injury patterns and clinical presentations of disorders involving the glenohumeral ligaments of the shoulder.

Mapping of the Inferior Glenohumeral Ligament for Suture Pullout Strength: A Biomechanical Analysis

Background

Suture pullout during rehabilitation may result in loss of tension in the inferior glenohumeral ligament (IGHL) and contribute to recurrent instability after capsular plication, performed with or without labral repair. To date, the suture pullout strength in the IGHL is not well-documented. This may contribute to recurrent instability.

Purpose/Hypothesis

A cadaveric biomechanical study was designed to investigate the suture pullout strength of sutures in the IGHL. We hypothesized that there would be no significant variability of suture pullout strength between specimens and zones. Additionally, we sought to determine the impact of early mobilization on sutures in the IGHL at time zero. We hypothesized that capsular plication sutures would fail under low load.

Study Design

Descriptive laboratory study.

Methods

Seven fresh-frozen cadaveric shoulders were dissected to isolate the IGHL complex, which was then divided into 18 zones. Sutures in these zones were attached to a linear actuator, and the resistance to suture pullout was recorded. A suture pullout strength map of the IGHL was constructed. These loads were used to calculate the load applied at the hand that would initiate suture pullout in the IGHL.

Results

Mean suture pullout strength for all specimens was 61.6 ± 26.1 N. The maximum load found to cause suture pullout through tissue was found to be low, regardless of zone of the IGHL. Calculations suggest that an external rotation force applied to the hand of only 9.6 N may be sufficient to tear capsular sutures at time zero.

Conclusion

This study did not provide clear evidence of desirable locations for fixation in the IGHL. However, given the low magnitude of failure loads, the results suggest the timetable for initiation of range-of-motion exercises should be reconsidered to prevent suture pullout through the IGHL.

Clinical Relevance

From this biomechanical study, the magnitude of force required to cause suture pullout through the IGHL is met or surpassed by normal postoperative early range-of-motion protocols.

Muscle activity and scapular kinematics in individuals with multidirectional shoulder instability: A systematic review

BACKGROUND

Several studies reported the importance of glenohumeral and scapular muscle activity and scapular kinematics in multidirectional shoulder instability (MDI), yet a systematic overview is currently lacking.

OBJECTIVE

This systematic review evaluates and summarizes the evidence regarding muscle activity and shoulder kinematics in individuals with MDI compared to healthy controls.

METHOD

The electronic databases PubMed and Web of Science were searched in September 2020 with key words regarding MDI (population), muscle activity, and glenohumeral and scapular movement patterns (outcomes). All studies that compared muscle activity or scapular kinematics between shoulders with MDI and healthy shoulders were eligible for this review, except for case reports and case series. All articles were screened on the title and abstract, and remaining eligible articles were screened on full text. The risk of bias of included articles was assessed by a checklist for case-control data, as advised by the Cochrane collaboration.

RESULTS

After full text screening, 12 articles remained for inclusion and one study was obtained by hand search. According to the guidelines of the Dutch Institute for Healthcare Improvement, most studies were of moderate methodological quality. We found moderate evidence that MDI individuals show increased or prolonged activity of several rotator cuff muscles that control and centre the humeral head. Furthermore, we found evidence of decreased and/or shortened activity of muscles that move or accelerate the arm and shoulder girdle as well as increased and/or lengthened activity of muscles that decelerate the arm and shoulder girdle. The most consistent kinematic finding was that MDI individuals show significantly less upward rotation and more internal rotation of the scapula during elevation of the arm in the scapular plane as compared with controls. Finally, several studies also suggest that the humeral head demonstrates increased translations relative to the glenoid surface.

CONCLUSION

There is moderate evidence for altered muscle activity and altered humeral and scapular kinematics in MDI individuals as compared with controls.

Evaluation of a novel portable three-dimensional scapular kinematics assessment system with inter and intraobserver reproducibility and normative data for healthy adults

Purpose

To evaluate the intra and interobserver reproducibility of a new system that assesses the three-dimensional humero-scapulo-thoracic kinematics using wearable technology in an outpatient setting. To obtain normative data with the system for scapular angular motions in three planes.

Methods

The SHoW Motion 3D kinematic tracking system is a motion analysis system that uses wireless wearable non-invasive inertial-magnetic sensors to assess the three-dimensional kinematics of the shoulder girdle. The sensors are placed over the skin in the sternum, scapular spine and arm to precisely define angular motions of the humerus and the scapula with three Degrees of Freedom (DOF) for each segment.

The system was used to measure the scapular angular motions in three planes (upward/downward rotation, internal/external rotation and anterior/posterior tilt) during two shoulder full-range movements (flexion/extension and abduction/abduction) in both shoulders of 25 healthy volunteers (13 males and 12 females, mean age: 37 [standard deviation 11.1] years). In a first measuring session one examiner made two evaluations alternating with another examiner that made a third evaluation. In a second session, one week apart, the first examiner made a fourth evaluation.

A mean curve was computed from the normalized data for each measurement to obtain normative data for scapular angular kinematics. Intra and inter-observer reproducibility was evaluated using Root Mean Square Error Estimation (RMSE) and Coefficients for Multiple Correlations (CMC).

Results

Both shoulders of the 25 volunteers were evaluated four times. The two hundred resulting kinematic analyses were pooled to get normative values for relations between humeral elevation angles and the three angular movements of the scapula.

The system showed at least very good (CMC > 0.90) intra and inter-observer reproducibility for scapular tilt and upward-downward rotations both in flexion and abduction. For scapular internal-external rotation the results were acceptable (CMC > 0.75) but not as good, especially for the abduction movement. RMSE calculations showed consistently good reproducibility with RSME< 4° for all three angles evaluated in flexion and abduction.

Conclusion

The SHoW Motion 3D kinematic tracking system is a quick, reproducible and easy to use system for the assessment of scapular angular kinematics in healthy adults. The data obtained is similar to that obtained with other validated methods.

Level of evidence

Level II.

Clinical relevance

The presented system is portable, easy to use and fast. It also has good intra and inter-observer reproducibility, making it a good tool to assess objectively scapular dyskinesis in the clinical setting. The normative data obtained is consistent with previous information available.

Towards an integrated clinical framework for patient with shoulder pain

Background

Shoulder pain (SP) represents a common musculoskeletal condition that requires physical therapy care. Along the years, the usual evaluation strategies based on clinical tests and diagnostic imaging has been challenged. Clinical tests appear unable to clearly identify the structures that generated pain and interpretation of diagnostic imaging is still controversial. The current patho-anatomical diagnostic categories have demonstrated poor reliability and seem inadequate for the SP treatment.

Objectives

The present paper aims to (1) describe the different proposals of clinical approach to SP currently available in the literature; to (2) integrate these proposals in a single framework in order to help the management of SP.

Conclusion

The proposed clinical framework, based on a bio-psychosocial vision of health, integrates symptoms characteristics, pain mechanisms and expectations, preferences and psychosocial factors of patients that may guide physiotherapist to make a diagnostic triage and to choose the right treatment for the individual patient.

Multidirectional instability of the glenohumeral joint: Etiology, classification, assessment, and management

Multidirectional instability of the shoulder is a type of glenohumeral joint shoulder instability. There are discrepancies in the definition and classification of this condition, which can make diagnosis and treatment selection challenging. Knowledge of contributing factors, the typical clinical presentation, and current best evidence for treatment options can assist in the diagnosis and appropriate treatment selection for this pathology. The purpose of this article is to present an overview of the current literature regarding the etiology, classification, assessment, and management of multidirectional instability of the glenohumeral joint.

The effects of a conservative rehabilitation program for multidirectional instability of the shoulder

BACKGROUND

Conservative management is commonly recommended as the first-line treatment for multidirectional instability (MDI) of the shoulder. Despite this, the evidence for efficacy of treatment is limited, and until recently, guidance for clinicians on conservative rehabilitation programs has been inadequate. This study evaluated the effectiveness of a physiotherapy-led exercise program for participants with MDI.

METHODS

In a single-group study design, 43 participants (16 male, 27 female; mean age, 19.8 years, standard deviation, 4.9 years) diagnosed with MDI undertook a 12-week exercise program. Primary outcome measures were the Melbourne Instability Shoulder Score, Western Ontario Shoulder Instability Index, and Oxford Shoulder Instability Score. Secondary outcomes were strength and scapular position. All measures were taken at baseline and repeated at the conclusion of the program. Test differences before and after rehabilitation were evaluated with dependent t tests and single-group effect size calculations (standardized mean difference [SMD]) to provide a measure of the magnitude of the difference.

RESULTS

Large effects were found between pre- and postrehabilitation scores on all functional instability questionnaires, with the Western Ontario Shoulder Instability Index demonstrating the largest effect (SMD, -3.04). Scapular upward rotation improved significantly in the early ranges of abduction (0°-60°), with moderate to large effects (SMDs, 0.54-0.95). All strength measures significantly improved, with large differences identified (SMDs, 0.69-2.08).

CONCLUSION

The identified improvement in functional status, shoulder muscle strength, and scapular positioning after rehabilitation allows greater confidence in the value of conservative management of MDI and informs further research by way of clinical trials in the area.

Multidirectional Instability: Natural History and Evaluation

Background:

Multidirectional instability (MDI) represents a great challenge to the orthopedic surgeon. When treating these patients we must be aware that instability refers to a symptomatic situation, thus multidirectional instability is defined as symptomatic involuntary instability in two or more directions, and should be clearly differentiated from asymptomatic hyperlaxity.

It may be associated with hyperlaxity, either congenital or acquired following repetitive stress, but also may be present without hyperlaxity, which is rare.

Methods:

We searched in the online data bases and reviewed the relevant published literature available.

Results:

Many differences can be seen in the current literature when identifying these patients, unclear definitions and criteria to be included in this patient group are common.

Conclusion:

Understanding the complex shoulder biomechanics as well as being aware of the typical clinical features and the key examination signs, which we review in this article, is of paramount importance in order to identify and classify these patients, allowing the best treatment option to be offered to each patient.

Glenohumeral and scapulohumeral kinematic analysis of patients with traumatic anterior instability wearing a shoulder brace: a prospective laboratory study

PURPOSE

To assess the effectiveness of a novel glenohumeral joint immobilizer, the S2 Shoulder Stabilizer^®, by evaluating shoulder kinematics with a stereophotogrammetry system.

METHODS

Participants in this prospective laboratory study were recruited from patients with anterior traumatic instability awaiting arthroscopic glenohumeral stabilization. Glenohumeral and scapulohumeral kinematic data (arm abduction-adduction and internal-external rotation, and scapular pronation-retraction and mediolateral rotation) were collected twice, without and with the brace, using a VICON™ motion capture system, and processed with MATLAB^® software.

RESULTS

The tests showed a significantly lower joint angle during abduction-adduction (p = 0.0022) and external rotation (p = 0.0076) and a significantly lower (p = 0.0022) mediolateral scapular rotation angle in the limbs wearing the immobilizer. Humeral head translation during abduction-adduction and internal-external rotation was also lower in the patients wearing the brace.

CONCLUSIONS

The immobilizer significantly limited joint excursion in all planes of movement except internal rotation. The narrower humeral head translation with respect to the trunk, measured in the tests with the brace, demonstrates that the immobilizer achieves the goal of preserving joint stability in the movements that are at risk of dislocation.

Multidirectional Shoulder Instability: Arthroscopic Labral Augmentation

Capsulolabral augmentation is one of the most used arthroscopic techniques to address multidirectional instability of the shoulder. Given the thin and weak capsule seen in the affected patients, reconstruction in this subset of patients can be particularly challenging. This arthroscopic technique aims to reduce the capsular volume and deepen the glenoid socket through the creation of a particularly voluminous "bumper" along the glenoid bone. Increasing the depth of the glenoid facilitates a concavity-compression stabilizing effect and, therefore, shoulder stability, especially midrange stability. This technique aims to augment the bump of the standard capsulolabral reconstruction by using a resorbable surgical mesh derived from porcine skin.