Anatomy and Biomechanics of the Unstable Shoulder

How does a motor or cognitive dual-task affect our sense of upper limb proprioception?

BACKGROUND

Daily upper limb activities require multitasking and our division of attention. How we allocate our attention can be studied using dual-task interference (DTi). Given the vital role proprioception plays in movement planning and motor control, it is important to investigate how conscious upper limb proprioception is impacted by DTi through cognitive and motor interference.

PURPOSE

To examine how dual-task interference impacts conscious upper limb proprioception during active joint repositioning tasks (AJRT).

METHODS

Forty-two healthy participants, aged between 18 and 35, took part in this cross-sectional study. Participants completed two AJRT during three conditions: baseline (single task), dual-cognitive task (serial subtractions), and dual-motor task (non-dominant hand movements). The proprioceptive error (PE; difference between their estimation and targeted position) was measured using an AJRT of 75% and 90% of maximum internal rotation using the Biodex System IIITM and the Upper Limb Proprioception Reaching Test (PRO-Reach). To determine if PEs differed during dual-task interference, interference change scores from baseline were used with one sample t-tests and analyses of variance.

RESULTS

The overall mean PE with the Biodex was 4.1° ± 1.9 at baseline. Mean change scores from baseline reflect a mean improvement of 1.5° ± 1.0 (p < .001) during dual-cognitive task and of 1.5° ± 1.2 (p < .001) during dual-motor task. The overall mean PE with the PRO-Reach was 4.4cm ± 1.1 at baseline. Mean change scores from baseline reflect a mean worsening of 1.0cm ± 1.1 (p < .001) during dual-cognitive task and improvement of 0.8cm ± 0.6 (p < .001) during dual-motor task. Analysis of variance with the Biodex PEs revealed an interference effect (p < .001), with the cognitive condition causing greater PEs compared to the motor condition and a criterion position effect (p = .006), where 75% of maximum IR produced larger PEs during both interference conditions. An interference effect (p = .022) with the PRO-Reach PEs was found highlighting a difference between the cognitive and motor conditions, with decreased PEs during the contralateral motor task.

CONCLUSION

Interference tasks did impact proprioception. Cognitive interference produced mixed results, whereas improved proprioception was seen during motor interference. Individual task prioritization strategies are possible, where each person may choose their own attention strategy when faced with dual-task interference.

Comparison of the Glenoid Index by Computed Tomography With Magnetic Resonance Imaging

Introduction Anterior shoulder instability results in labral and osseous glenoid injuries. With a large osseous defect, there is a risk of recurrent dislocation of the joint, and therefore the patient has to undergo surgical correction. An MRI evaluation of the patient helps to assess the soft tissue injury. Currently, the volumetric three-dimensional (3D) reconstructed CT image is the standard for measuring glenoid bone loss and the glenoid index. However, it has the disadvantage of exposing the patient to radiation and additional expenses. This study aims to compare the values of the glenoid index using MRI and CT. Methodology The present study was a two-year cross-sectional study of patients with shoulder pain, trauma, and dislocation in a tertiary hospital in Karnataka. The sagittal proton density (PD) section of the glenoid and enface 3D reconstructed images of the scapula were used to calculate glenoid bone loss and the glenoid index. The baseline data were analyzed using descriptive statistics, and the Chi-square test was used to test the association of various complications with selected variables of interest. Results The glenoid index calculated in the current study using 3D volumetric CT images and MR sagittal PD images was 0.95±0.01 and 0.95±0.01, respectively. The CT and MRI glenoid bone loss was 5.41±0.65% and 5.38±0.65%, respectively. When compared, the glenoid index and bone loss calculated by MRI and CT revealed a high correlation and significance with a p-value of <0.001. Conclusions The study concluded that MRI is a reliable method for glenoid measurement. The sagittal PD sequence combined with an enface glenoid makes it possible to identify osseous defects linked to glenohumeral joint damage and dislocation. The values derived from 3D CT are identical to the glenoid index and bone loss determined using the sagittal PD sequence in MRI.

Effect of Indian clubbell exercises on cricket fast bowlers' shoulder kinematics

Background

The glenohumeral joint's rotational range of motion (ROM) and muscle strength are essential to execute the cricket bowling action. Performing shoulder rotation exercises may increase the rotator cuff muscle strength and rotational ROM.

Objectives

The aim of this study was to test the effect of a six-week exercise programme on shoulder rotational ROM and muscle strength.

Methods

Twenty-one healthy male cricket fast bowlers were recruited, ranked and pair-matched on initial shoulder rotator muscle strength and assigned to either a shoulder exercise (SE) group or cricket training (CT) only group. The SE group incorporated Indian clubbell exercises in addition to their cricket training.

Results

Bowlers in both groups displayed a large increase on the dominant shoulder's internal rotation (IR) ROM, but only the SE group's bowlers displayed ROM improvements (p<0.001) bilaterally for both internal and external rotation. The CT group's fast bowler's non-dominant shoulder IR ROM significantly decreased (p=0.02) during the six weeks. Between groups, only the SE group's bowler's internal rotator muscle strength improved (p<0.001) bilaterally. The observed kinematic changes were statistically significantly greater at a 5% level for the SE group's bowlers (bilateral internal rotators muscle strength, non-dominant shoulder IR ROM and horizontal adduction ROM).

Conclusion

Maintenance of the shoulder's rotational ROM and muscle strength is vital for a fast bowler. Cricket bowlers who perform regular clubbell exercises might increase their shoulder's ROM and internal rotator cuffs' muscle strength, which may aid in stabilising their glenohumeral joint while bowling.

Cyst formation and bony ingrowth inside coil-type open-architecture anchors used for arthroscopic remplissage: a volumetric computed tomographic study of 50 anchors

BACKGROUND

The use of anchors in the proximal humerus during arthroscopic surgery can cause localized bone loss due to osteolysis and cyst formation. The purpose of this study was to use computed tomography (CT) to evaluate the incidence of implant-related bone loss and cyst formation after implantation of polyetheretherketone (PEEK) coil-type open-architecture anchors during remplissage for the management of Hill-Sachs defects (HSDs) in patients with shoulder instability.

METHODS

This was a single-cohort, observational study with a minimum of 12 months of follow-up. Subjects undergoing arthroscopic instability surgery with HSD requiring remplissage were included. The volume of the bone defects and the degree of bony ingrowth into the anchor were measured on CT images.

RESULTS

Thirty-one participants (28 males, 3 females; mean age 29.4 years, standard deviation [SD] 10.6) in whom 50 anchors (4.5-mm Healicoil PEEK double-loaded anchors) were used were evaluated with a CT performed at a mean of 14.1 (SD 3.74) months after surgery. Full bony ingrowth inside the anchor was found in 15 anchors (30%, range 17.8%-44.5%); clear ossification with a thin lucent rim was found in 10 anchors (20%, range 10.0%-33.7%); discontinuous ossification was found in 8 anchors (16%, range 7.2%-29.1%); and no ossification was observed inside 17 anchors (34%, range 21.2%-48.7%). Regarding bone defect size, no bone defect was identified in 15 anchors (30%, 95% CI 17.9%-44.6%), a partial bone defect was found in 17 anchors (34%, 95% CI 21.2%-48.7%), hole enlargement was found in 17 anchors (34%, 95% CI 21.2%-48.7%), and 1 anchor caused a cyst larger than twice the size of the hole made for anchor insertion (2%, 95% CI 0.1%-8.6%). At the 1-year evaluation, none of the participants presented recurrence or residual apprehension.

CONCLUSION

The use of PEEK coil-type open-architecture anchors for remplissage during instability surgery caused large cystic lesions in less than 10% of anchors. There was full bony ingrowth in one-third of anchors, and partial cancellous bone ingrowth occurred in another third of anchors.

Assessment of shoulder proprioception in patients with chronic mechanical cervical pain: A comparative study

BACKGROUND

Chronic mechanical cervical pain (CMCP) is a common disabling problem worldwide, interfering with upper extremities function. However studying the impact of CMCP on shoulder proprioception is still lacking.

OBJECTIVE

To investigate the impact of CMCP on shoulder proprioception in young adults compared with normal control (NC) individuals.

METHODS

A comparative study was conducted between two groups; 40 patients with CMCP (mean age 32.28 ± 6.586) and 40 age and sex matched NC (mean age 33.43 ± 9.021). The Biodex isokinetic dynamometer was used to assess shoulder active sense of position at 30∘ external and internal rotations. The absolute angular error was calculated for the dominant and non-dominant shoulders.

RESULTS

The absolute angular error was significantly increased only in the CMCP at both rotation angles for both shoulders, showing a remarkable increase on the dominant shoulder and in the external rotation range compared with NC.

CONCLUSIONS

CMCP can significantly impair shoulder proprioception, particularly on the dominant side and in external rotation range. This could emphasize the careful examination of shoulder proprioception for the early detection of shoulders at risk, to eliminate the possibility of shoulder instability and/or injury in young adults with CMCP.

A stabilizing role of the glenoid labrum: the suction cup effect

BACKGROUND

The glenoid labrum acts as a bumper, deepening glenoid concavity and amplifying the concavity-compression mechanism, and serves as the scapular attachment for glenohumeral ligaments. The role of the posterosuperior labrum in anteroinferior glenohumeral stability, and the role of the anterior labrum in posterior stability has been debated. The purpose of this study was to quantify the contribution of anteroinferior and posterosuperior labral tears to loss of glenohumeral stability in multiple directions.

METHODS

Fourteen fresh-frozen cadaveric shoulders were tested on a custom stability ratio measurement apparatus. The peak force that was required to translate the humeral head in anterior, anteroinferior, posterior, and posteroinferior directions was measured under 5 conditions: intact labrum (n = 14), anteroinferior labral tear (n = 7), posterosuperior labral tear (n = 7), combined labral tear (n = 14), and no labrum (n = 14). The stability ratio was defined as the peak translational force divided by the compressive force. Within force-translation curves, we defined the suction cup effect as the force required to release the negative pressure created by an intact labrum.

RESULTS

The suction cup effect was usually present with the intact labrum and always disappeared after removal of the labrum for anterior (100% vs. 0%) and posterior (86% vs. 0%) translations (P < .001). After creation of an anteroinferior labral tear, the stability ratio for posterior direction decreased (P < .001) and the suction cup effect disappeared (P < .001). After creation of a posterosuperior labral tear, stability ratios in the anterior and anteroinferior directions decreased (P ≤ .006) and the suction cup effect disappeared (P ≤ .015). The stability ratio for anterior and anteroinferior testing was more diminished by posterosuperior labral tears than anteroinferior labral tears, and the stability ratio for posterior testing was more diminished by anteroinferior labral tears than posterosuperior labral tears.

CONCLUSION

Anteroinferior labral tears decreased posterior stability and posterosuperior labral tears decreased anterior and anteroinferior stability, largely because of loss of the suction cup effect.

Long-Term Results of Arthroscopic Bankart Repair for Anterior Glenohumeral Instability: Does Associated Postero-inferior Capsulolabral Repair Still Have a Role?

PURPOSE

To compare the outcomes of arthroscopic anterior Bankart repair with and without associated postero-inferior capsulolabral repair as treatment of anterior glenohumeral instabiliy at minimun 10 year follow-up.

METHODS

A retrospective comparative study including patients who underwent arthroscopic anterior Bankart repair to treat anterior glenohumeral instability with glenoid bone-loss < 15% between January 2000 and February 2010 was performed. Outcomes were reported as recurrence rate, type of recurrence (dislocation or subluxation), need for revision surgery, range of motion, complications, and functional status. Outcomes were compared depending on whether a postero-inferior capsulolabral repair was added to the anterior Bankart repair.

RESULTS

70 shoulders [59 males, mean age 28.2 (range 14-56), mean follow-up 146.1 (range 120-208) months] were included. Recurrence occurred in 9 cases (12.8%), including 3 dislocations and 6 subluxations. Revision surgery was needed in 8 (11.4%). Mean Rowe score improved from 29.7 (11.6) preoperatively to 87.1 (12.3) postoperatively. 83.3% returned to previous sports activities. Mean forward flexion changed from 173.5° (19.2) to 168.4º(10.4) (P < 0.01), external rotation from 81.4° (18) to 75.7° (10.5) (P < 0.01), and internal rotation decreased from 66.2% reaching T12 to 14.1% (P < 0.01). Addition of postero-inferior capsulolabral repair did not influence any of the outcomes significantly.

CONCLUSION

Postero-inferior capsulolabral repair added to anterior Bankart repair as treatment of anterior glenohumeral instability in abscence of significant glenoid bone-loss did not influence the outcomes in terms of recurrence, range of motion, return to sports, or functional status, compared to isolated anterior Bankart repair at 12.2 year follow-up.

LEVEL OF EVIDENCE

Level III.

Injuries in Wheelchair Basketball Players: A Systematic Review

BACKGROUND

Sports injuries have physical and psychological effects that negatively affect sports performance. Although there are data available on sports injuries in wheelchair basketball, some aspects need to be clarified, such as the location, mechanisms and risk factors for injury, which are not well described due to variations and/or a lack of definition of injury. The aim of this study was to determine epidemiological information, primary injury characteristics and affected body regions in wheelchair basketball players; Methods: The PubMed, Science Direct, Scopus, Web of Science and Google Scholar databases were used; Results: eight articles were included in this review. The shoulder was the body region most affected (N = 60; 22.1%). When divided by body segments, the upper limbs were the most affected (N = 128; 47.2%), followed by the head and/or face (N = 53; 19.5%), trunk (included spine and ribs) (N = 48; 17.8%) and lower limbs (N = 42; 15.5%); Conclusions: wheelchair basketball players suffer a large number of injuries with different characteristics that are mainly linked to biomechanics and sport. These results can be used to guide coaches in structuring training to minimize recurring injuries, in addition to assisting in the organization of medical teams in competitions.

Efficacy and safety of kinesiology tape for hemiplegic shoulder pain: A systematic review and meta-analysis of randomized controlled trials

OBJECTIVE

The aim of this study was to examine the efficacy and safety of kinesiology tape in treating hemiplegic shoulder pain.

METHODS

Web of Science, MEDLINE, Embase, Cochrane Library, six other English databases and three Chinese databases (CNKI, VIP, Wan Fang) were searched for randomized controlled trials published prior to December 13, 2020 in English or Chinese on the use of kinesiology tape for hemiplegic shoulder pain.

RESULTS

Fourteen randomized controlled trials (679 patients) of good PEDro quality (6.43 ± 1.09) were included in this meta-analysis. The pooled results for pain (SMD -0.92, 95% CI -1.10 to -0.74, P< 0.001, 10 RCTs, 539 patients), range of motion (SMD 2.27, 95% CI 1.23 to 3.32, P< 0.001, 7 studies, 320 patients), the acromion humeral distance (SMD -0.62, 95% CI -0.88 to -0.37, P< 0.001, 7 RCTs, 246 patients) and the FMA-UE score (SMD 0.66, 95% CI 0.41 to 0.91, P< 0.001, 5 RCTs, 263 patients) suggested that therapeutic kinesiology tape relieved pain, increased ROM, shortened the acromion humeral distance and improved upper extremity motor function to a greater extent than the sham or blank control conditions. The pooled results for individual activity (SMD 0.42, 95% CI -0.22 to 1.07, P= 0.199, 5 RCTs, 199 patients) and quality of life (SMD 0.308, 95% CI -0.288 to 0.903, P= 0.311, 1 RCT, 44 patients) showed that the kinesiology tape group was not significantly different from the sham or blank control group. Publication bias was not observed. No adverse events were reported in any of the included studies.

CONCLUSION

KT relieved pain and improved the ROM, DAH and FMA-UE score in patients with HSP to a greater extent than did the sham KT or blank control conditions. The effects on independence in activities of daily living and quality of life and whether this method is superior to active treatment in patients with HSP were not verified. More rigorous, reasonably designed RCTs with large sample sizes are still needed in the future.

In vivo effects of two shoulder girdle motor control exercises on acromiohumeral and coracohumeral distances in healthy men

INTRODUCTION

Altered motor control and proprioceptive deficits are associated with kinematics dysfunctions and may cause alterations in subacromial space (SAS) that could lead to shoulder pathologies. Dimensions of the subacromial space, as well as interventions aimed at its normal restitution, can be explored by ultrasound (US).

OBJECTIVE

To describe the effect of two shoulder girdle motor control exercises with cognitive training strategies on SAS dimensions, measured with US.

METHODS

Cognitive movement control strategies, with visual and haptic feedback were applied on 21 healthy participants. SAS dimensions were measured through in vivo variations of acromiohumeral (AHD) and coracohumeral distances (CHD) using US.

RESULTS

Our results show that as exercise repetitions are performed, an increasing trend in both measures can be observed, being wider for AHD (i.e. humeral head descent exercise) than CHD (i.e. scapular retraction exercise).

CONCLUSION

Specific cognitive and motor control exercises improve congruence joint and centering of the humeral head.

Arthroscopic remplissage with all-suture anchors causes cystic lesions in the humerus: a volumetric CT study of 55 anchors

PURPOSE

To evaluate with computed tomography (CT) the incidence of implant-related osteolysis after implantation of two types of all-suture anchors during remplissage for the management of Hill-Sachs lesions in shoulder instability.

METHODS

Single-cohort, observational study with a minimum of 12 months follow-up. Twenty-five participants (19 males and 6 females; mean age 37.4 years [SD: 11.6]) with Hill-Sachs lesions requiring remplissage were evaluated with a CT performed a mean of 14.1 [3.74] months after surgery. Fifty-five all-suture anchors (19 2.3 mm Iconix and 36 1.7 mm Suturefix) were used. The volume of the bone defects was measured in the CT. Every anchor was classified into one of four groups: (1) no bone defect. (2) Partial bone defect (bone defects smaller than the drill used for anchor placement). (3) Tunnel enlargement (bone defect larger than the drill volume but smaller than twice that volume). (4) Cystic lesion (bone defect larger twice the drill volume).

RESULTS

No bone defect was identified in only two anchors (3.6%, 95% CI 0.4-12.5%). A partial bone defect was found in eight anchors (14.5%, 95% CI 6.5-26.7%). In 35 anchors (63.6%, 95% CI 49.6-76.2%), there was enlargement of the bone defect that was smaller than 200% the size of the drill used. Ten anchors caused bone defects larger than twice the size of the drill used (18.2%, 95% CI 9.1-30.9%). The defect size was a mean of 89 mm³ (SD: 49 mm³, minimum 0 mm³, maximum 230 mm³).

CONCLUSION

When using all-suture anchors in arthroscopic remplissage during instability surgery, relevant bone osteolytic defects are common at 1-year-follow-up. Cystic defects larger than twice the volume of the resected bone during implantation develop in one in six anchors and significant tunnel widening will develop in another three out of five anchors. This bone loss effectively increases the size and depth of the Hill-Sachs lesions but does not seem to affect short-term clinical outcomes.

LEVEL OF EVIDENCE

Level IV.

Latarjet Procedure for the Treatment of Anterior Glenohumeral Instability in the Athlete - Key Considerations for Rehabilitation

The Latarjet procedure with transfer of the coracoid process and its attached conjoint tendon is a well-established surgical technique for the treatment of anterior glenohumeral instability in patients with anteroinferior bone loss and/or high risk for recurrence. Biomechanical and clinical studies have shown excellent results and high rates of return to sports. However, there is an absence of standardized, objective criteria to accurately assess an athlete's ability to progress through each phase of rehabilitation. Return to sports rehabilitation, progressed by quantitatively measured functional goals, may improve the athlete's integration back to sports participation. Therefore, the purpose of this clinical commentary is to provide a rehabilitation protocol for the Latarjet procedure, progressing through clearly defined phases, with guidance for safe and effective return to sport. Recommended criteria are highlighted which allows the clinician to progress the patient through each phase appropriately rather than purely following timeframes from surgery. This progression ensures the patient has completed a thorough rehabilitation program that addresses ROM, strength, power, neuromuscular control and a graded return to play. Level of Evidence: 5.

Comprehensive review of the physical exam for glenohumeral instability

Glenohumeral instability is a common pathology of the shoulder joint, especially among young athletes. Despite advancements in technology and the widespread use of diagnostic imaging, a careful history and physical examination still remain the cornerstone of diagnosing patients with shoulder instability. Due to the involvement of many static and dynamic stabilizers, proficient physical examination can be challenging. With a systematic approach to clinical evaluation, the clinician can recognize characteristic patterns of relevant signs and symptoms and make an accurate diagnosis.

Systematic Review of the Anatomic Descriptions of the Glenohumeral Ligaments: A Call for Further Quantitative Studies

PURPOSE

To perform a systematic review of the glenohumeral ligament anatomic attachments on the glenoid and humeral neck.

METHODS

A systematic review was performed according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines using the Cochrane Database of Systematic Reviews, the Cochrane Central Register of Controlled Trials, PubMed, MEDLINE, and Embase from 1980 to present. The inclusion criteria were as follows: cadaveric or clinical anatomic studies that qualitatively or quantitatively described the glenoid and humeral attachments of the glenohumeral ligaments in the English-language literature. Imaging and animal studies, editorial articles, and surveys were excluded from this study.

RESULTS

The 15 included studies analyzed a total of 983 shoulders. Only 5 studies reported quantitative measurements. The most common glenoid superior glenohumeral ligament attachment described was in the anterolateral region of the supraglenoid tubercle and was inserting on the humerus in close vicinity to the subscapularis tendon insertion. The superior labrum and lesser tuberosity were the most commonly reported middle glenohumeral ligament attachments. The inferior glenohumeral ligament was most commonly described to attach between the 2- and 4-o'clock positions of the glenoid and distally near the surgical neck of the humerus.

CONCLUSIONS

There were limited quantitative data on the attachments of the glenohumeral ligaments. Although the literature was discordant, the most common descriptions of the attachments were as follows: The anterolateral region of the supraglenoid tubercle, the superior labrum, and the glenoid (between the 2- and 4-o'clock positions) were the medial attachments for the superior glenohumeral ligament, middle glenohumeral ligament, and inferior glenohumeral ligament, respectively. Laterally, they inserted on the humerus in close vicinity to the subscapularis tendon insertion, on the lesser tuberosity, and near the surgical neck of the humerus, respectively.

CLINICAL RELEVANCE

The glenohumeral ligaments are important anatomic structures contributing to the dynamic stability of the glenohumeral joint. Further detailed quantitative descriptions of their attachments are required for truly anatomically based repairs.