Effect of coracoacromial ligament resection on glenohumeral stability under active muscle loading in an in vitro model

Modified Suture-Button Latarjet Procedure With Coracoacromial Ligament and Pectoralis Minor Preservation Achieves Good Clinical Outcomes at 2-Year Follow-Up: Case Series of Latarjet Technique

PURPOSE

To evaluate whether the modified suture-button Latarjet procedure with coracoacromial ligament (CAL) and pectoralis minor (PM) preservation could achieve excellent outcomes at the 2-year follow-up.

METHODS

During January 2019 to January 2021, the data of patients who underwent modified suture-button Latarjet with CAL and PM preservation in our department were collected. The glenoid bone loss of these patients was greater than 20% or greater than 10% with high demands for exercise. Partial coracoid osteotomy was based on the results of a preoperative 3-dimensional computed tomography evaluation of the glenoid defect area and corresponding coracoid process morphology. The preoperative and postoperative clinical results were assessed. The minimal clinically important difference (MCID) was used to compare improvement in clinical outcomes. Graft-glenoid union and remodeling were assessed using postoperative 3-dimensional computed tomography, and magnetic resonance imaging was performed to confirm the integrity of the CAL and PM postoperatively.

RESULTS

In total, 35 patients were included in this study; the mean follow-up time was 26.9 ± 1.9 months. No case of recurrent dislocation or sublaxity. Significant improvements were observed in mean visual analog scale (VAS) scores for pain during motion, American Shoulder and Elbow Surgeons (ASES) score, Rowe score, and Walch-Duplay score (P < .001). The percentage of patients achieving at least an MCID improvement in clinical outcomes was VAS 85.71%, ASES 97.14%, Rowe 100%, and Walch-Duplay 97.14%. Thirty-three patients (94.3% of all cases) were able to return to their preoperative sport levels, 34 grafts (97.1%) achieved bone union (1 soft union) in 6.3 ± 2.2 months, and the coracoid grafts restored 97.1 ± 4.0% of the perfect-fitting circle at the last follow-up. Postoperative computed tomography scan showed that 31 grafts (88.6%) were placed ideally in vertical view. In the axial view, 25 grafts (82.9%) were flushed to the glenoid, whereas 1 and 5 grafts were fixed medially and laterally, respectively. The CAL and PM were visualized postoperatively. No arthropathy was observed in any patient at the last follow-up.

CONCLUSIONS

The modified suture-button Latarjet procedure with CAL and PM preservation obtained good clinical and radiological results without recurrence or complications. A substantial number of patients (>85%) achieved the MCID for the VAS, ASES, Rowe, and Walch-Duplay scores. In addition, the malpositioned graft (17.1%) did not cause arthropathy of the joints at 2-year follow-up.

LEVEL OF EVIDENCE

Level IV, retrospective case series.

Association of Coracoacromial Ligament Degeneration With Rotator Cuff Tear Patterns and Retear Rate

Background

Coracoacromial ligament (CAL) degeneration is thought to be a factor in external impingement in bursal-sided rotator cuff tears, but CAL release is associated with adverse effects.

Purpose

To investigate the association between CAL degeneration and the patterns of massive rotator cuff tears using multiple modalities and to assess the effect of CAL degeneration on supraspinatus tendon retear rates.

Study Design

Cohort study; Level of evidence, 2.

Methods

The authors prospectively recruited 44 patients who had undergone arthroscopic rotator cuff repair without acromioplasty or CAL release. Preoperative radiographs and magnetic resonance imaging (MRI) scans were reviewed to determine acromial morphology and CAL thickness, respectively. Rotator cuff tears were categorized as isolated supraspinatus or massive (involvement of ≥2 tendons), with massive tears categorized using the Collin classification. Acromial degeneration was analyzed using the Copeland-Levy classification. The CAL was biopsied intraoperatively and histologically analyzed using the Bonar score. At 6-month follow-up, the integrity of the repaired supraspinatus tendon was analyzed on MRI using the Sugaya classification. Finally, the associations among CAL degeneration, rotator cuff tear pattern, and arthroscopic grading were investigated.

Results

Patients with Collin type B rotator cuff tear had significantly higher CAL Bonar scores than those with Collin type A or isolated supraspinatus tears (10.0 vs 6.8 and 3.4; P = .03 and P < .001, respectively). Patients with a degenerative acromial undersurface of Copeland-Levy stage 2 or 3 had CALs with significantly higher Bonar scores than those with an intact acromial undersurface (8.4 and 8.2 vs 3.5; P = .034 and P = .027, respectively). The CAL Bonar scores of patients with different stages of the 6-month postoperative Sugaya classification were comparable (6.5, 7.2, 8.0, and 7.8 for stages 1, 2, 3, and 4, respectively; P = .751).

Conclusion

CAL degeneration was more severe in anterosuperior-type massive rotator cuff tears. Interestingly, even without acromioplasty, the severity of CAL degeneration did not affect the retear rate of the supraspinatus tendon.

Outcomes of Arthroscopic Tuberoplasty for Symptomatic Irreparable Rotator Cuff Tendon Tear Without Pseudoparalysis

Background

The purpose of this study is to report the outcomes in patients undergoing arthroscopic tuberoplasty for symptomatic irreparable rotator cuff tear (RCT).

Methods

This is a retrospective cohort study comparing preoperative and postoperative data of patients undergoing arthroscopic tuberoplasty for symptomatic irreparable RCT. Exclusion criteria included open tuberoplasty, concomitant partial RCT repair, glenohumeral arthritis, concomitant ipsilateral extremity fractures, <12 months follow-up, or pseudoparalysis. Demographics, shoulder range of motion (ROM), RCT morphology, re-operation rates, satisfaction and outcome scores were collected from medical records and questionnaires. Outcome scores included Patient Reported Outcome Measurement Information System Upper Extremity (PROMIS), American Shoulder and Elbow Surgeons score (ASES), Subjective Shoulder Value (SSV), and pain Visual Analog Score (VAS).

Results

Out of 28 patients identified between 2012 and 2019, 20 (21 shoulders) were available for follow-up at a mean of 43.3 ± 20.9 months. Mean age was 64.6 ± 8.8 years. Mean PROMIS was 37.7 ± 7.3, ASES was 82.9 ± 13.8, and SVV was 67.1 ± 19.4. VAS with activity decreased from 5.0 ± 2.9 preoperatively to 2.3 ± 2.6 (P = .0029). Pre- and post-operative ROM were unchanged. There were 4 failures requiring revision. The remaining 17 patients reported high satisfaction scores (3.4 ± 0.7) and 15 (88.2%) answered “yes” to getting the procedure again, with 3/4 failures stating they would also undergo arthroscopic tuberoplasty again.

Conclusion

Arthroscopic tuberoplasty demonstrates high levels of satisfaction and pain reduction in symptomatic irreparable RCT. In appropriately indicated patients, this treatment should be considered prior to other salvage options.

LUtarjet-limit unique coracoid osteotomy Latarjet (With video)

Background

The Latarjet procedure is an effective technique for the treatment of recurrent anterior shoulder dislocation with glenoid bone loss. However, the inevitable destruction of the coracoacromial arch may result in humeral head translation. The aim of the study is to introduce a modified Latarjet technique with coracoacromial arch preservation as well as its short term clinical outcomes.

Methods

We propose a novel individualized flexible arthroscopic suture button fixation Latarjet technique called `LUtarjet' with video. Precise measurements of the coracoid process, glenoid deficiency and osteotomy plane were made preoperatively. Only three arthroscopic portals were needed and limit unique coracoid osteotomy was performed with coracoacromial arch preservation. The mini window splitting of the subscapularis was performed from the posterior to the anterior direction and the split window was as small as 8–10 mm in length.

Results

A total of 27 patients (25.6 ± 5.4 years) were included in the study. The average surgical duration was 55.6 ± 6.3 min and the mean follow-up time was 8.1 ± 1.5 months. The functional score was significantly improved at the last follow-up. Radiologic evidence showed that the bone graft healing was placed in the desired position. No complications were found.

Conclusions

We present a fast, easy, accurate, safe arthroscopic ‘LUtarjet’ technique called FEAST that can simplify the arthroscopic Latarjet process and achieve a satisfactory bone graft position and satisfactory short-term clinical outcomes.

Level of evidence

IV, case series.

Arthroscopic Subscapularis Augmentation Using the Long Head of the Biceps Tendon for Anterior Shoulder Instability

The limitations of transferring the coracoid process along with the conjoined tendon are coracoacromial arch damage, technical difficulty, and nerve injury. The long head of the biceps tendon (LHBT) proximal transposition technique has a weaker sling effect and a risk of nerve injury. The arthroscopic subscapularis augmentation technique may have risks of shoulder external rotation restriction and subscapularis transection. Herein, we introduce an arthroscopic technique for the transfer of the LHBT for subscapularis augmentation to address these risks. Indications of this technique were patients younger than 45 years of age who engage in competitive sports, require forceful external rotation and abduction, have a related capsule-ligament insufficiency, and have a glenoid bone loss <25%. The steps include detaching the LHBT at the upper edge of the pectoralis major, transecting and braiding the LHBT, establishing a scapular tunnel, placing a guide suture through the upper third of the subscapular and scapular tunnel, passing the LHBT through the established tunnels, and fixating the LHBT. This technique achieves stability of the anterior shoulder by transecting and transferring the distal end of the LHBT to press on the upper third of the subscapularis muscle.

Effect of Modified Arthroscopic Latarjet on Acromiohumeral Distance at 5-Year Follow-up

Background:

It is unclear whether coracoacromial ligament release during the Latarjet procedure will increase superior translation of the shoulder joint.

Purpose:

To evaluate whether a modified suture button Latarjet procedure can decrease the acromiohumeral distance (AHD).

Study Design:

Case series; Level of evidence, 4.

Methods:

A retrospective analysis was conducted among 155 patients who underwent a modified suture button Latarjet procedure between 2013 and 2015. AHD was measured on bilateral computed tomography scans taken preoperatively and on scans of the affected shoulder taken on postoperative day 1 and postoperative month (POM) 6, POM 36, and POM 60. At each time point, we recorded pain on a visual analog scale (VAS) and objective shoulder function using the American Shoulder and Elbow Surgeons, Rowe, and Walch-Duplay scores. Preoperative and final follow-up VAS and functional scores were compared using the paired t test. Pairwise comparison of AHD values at each follow-up time point were compared with the preoperative intact side using the paired t test. Intra- and interobserver reproducibility of the AHD measurements was evaluated using the intraclass correlation coefficient.

Results:

A total of 104 patients who met the criteria completed the final follow-up, which occurred at 62.6 ± 2.4 months (mean ± SD). When compared with presurgery, the VAS and all functional scores improved significantly at the last follow-up (P < .001 for all). Intra- and interobserver intraclass correlation coefficients indicated good reliability for the ADH measurements. Preoperatively, there were no differences in AHD values between the intact and affected shoulders (7.8 ± 0.8 mm for both; P = .851). The AHD values at postoperative day 1 and POM 6, POM 36, and POM 60 were 9.6 ± 0.7 mm, 8.6 ± 0.9 mm, 8.0 ± 0.8 mm, and 7.9 ± 0.8 mm, respectively, all of which were larger than those of the preoperative intact side (P < .001 for all).

Conclusion:

The modified suture button Latarjet procedure not only offered satisfactory therapeutic effects but also did not decrease the AHD at 5-year follow-up.

Does Preservation of Coracoacromial Ligament Reduce the Acromial Stress Pathology Following Reverse Total Shoulder Arthroplasty?

Introduction

Acromial pathologies (AP), such as acromial stress reaction (ASR), acromial stress occult fracture (ASOF), and acromial stress fracture (ASF), are known as complications that deteriorate the clinical score and patient satisfaction after reverse total shoulder arthroplasty (RSA). Several factors that increase stress on the acromion have been reported as risk factors for AP, but this is also unclear. Thecoracoacromial ligament (CAL) is a structure that distributes the stress loading on such an acromion, although its importance has been mentioned, there is a lack of research. Therefore, we investigated the incidence of AP according to the preservation of the CAL and whether it is a risk factor.

Methods

The study was retrospectively conducted on patients who underwent RSA from 2016 and 2018. Patients with CAL transection was classified into group 1 and CAL preservation was classified into group 2. ASR and ASOF were identified through symptoms and ultrasound, and ASF identified through simple radiograph or computed tomography. The incidence of AP in each group was checked and compared.

Results

Of the total of 265 patients. Among 197 cases of group 1, 21 cases of ASR(10.7%), 28 cases of ASOF (14.2%),10 cases of ASF (5.1%), and 59 cases of total AP (29.4%). Among 68 cases in group 2, 2 cases (2.9%) of ASR, 6 cases of ASOF(8.8%), 1 case of ASF (1.5%), and 9 cases of total AP (13.2%). It was confirmed that ASR and ASOP were significantly decreased in the group preserving CAL. (P = .008)

Conclusion

In the case of preservation of CAL during surgery, it was confirmed that the incidence of ASR, ASOF was reduced. Therefore, preservation of CAL can be regarded as a modifiable risk factor that can reduce the risk of AP by distributing the stress applied to acromion after RSA surgery.

Clinical outcome and return to sports activity after surgical treatment for recurrent shoulder instability with a modified Latarjet procedure

INTRODUCTION

The Latarjet procedure is an attractive surgical option for the management of chronic anterior shoulder instability. The original surgical approach involves the vertical tenotomy of the subscapularis tendon. Alternatively, the subscapularis muscle is split longitudinally and the tendon left attached at the lesser tuberosity.

HYPOTHESIS

The hypothesis is that the longitudinal split is of functional advantage and may lead to better functional results and earlier return to sports activities compared to the vertical tenotomy.

MATERIAL AND METHODS

Thirty-two patients were included in this retrospective cohort study. In 14 patients, the subscapularis tendon was vertically incised (group A), whereas in 18 patients, the subscapularis muscle was split longitudinally (group B). Patients were evaluated at 1 year (FU1) and 2 years (FU2) after the Latarjet procedure. Results at follow-up were correlated with patient-specific data and compared with the preoperative status. Primary outcomes were the functional assessment based on Western Ontario Shoulder Instability (WOSI) index and Constant Score (CS) and the assessment of the return to sports activity. Patients' demographics, duration of surgery, and the rate of recurrent dislocations were recorded as secondary variables.

RESULTS

All patients started their sports activities with a mean±SD of 12.41±1.24 weeks. Interestingly, the time from surgery to full recovery of sports activities was significantly longer for group A (mean±SD of 30.17±10.36 weeks) compared to group B (mean±SD of 20.71±3.67 weeks). There is a statistically significant decrease of the WOSI score from the preoperative level compared to FU1 and FU2, indicating a decrease in instability related symptoms during the entire follow up period with no statistically significant difference between group A and B. There is an increase in shoulder function during the entire follow up period based on the CS. Most interestingly, there is a statistically significant difference between group A and B at FU1, indicating a significantly better shoulder function for group B at the early follow up timepoint (FU1). At the later follow up timepoint (FU2), no difference exists in the individual items. However, a significantly better total CS remains in group B, indicating an overall improved function compared to group A.

DISCUSSION/CONCLUSION

The longitudinal split of subscapularis muscle is a safe approach which leads to quicker functional recovery and return to sports activity compared to the vertical tenotomy, which is a benefit especially for active individuals. It is therefore recommended as the standard surgical approach.

LEVEL OF EVIDENCE

III; Retrospective cohort study.

The novel arthroscopic subscapular quadriceps tendon-bone sling procedure provides increased stability in shoulder cadavers with severe glenoid bone loss

PURPOSE

Treatment of anterior glenoid bone loss in patients with recurrent anterior shoulder instability is a challenge. The subscapular sling method with quadriceps tendon bone (QTB) graft is a modification of the subscapular sling with a semitendinosus (ST) graft. The aim of the study was to test the biomechanical stability of the QTB sling procedure in human shoulder cadavers with severe anterior glenoid bone loss.

METHODS

Fourteen cadaveric shoulders were tested with a force-moment-guided robot in three conditions: physiologically intact, anterior glenoid bone resection, and the subscapular sling procedure with a QTB graft. Joint stability was measured in anterior, anterior inferior and inferior directions in four glenohumeral joint positions: 0° and 60° of glenohumeral abduction, with each at 0° and 60° of external rotation. Maximum external rotation was measured at 0° and 60° glenohumeral abduction. Computer tomography scans were obtained preoperatively to plan the glenoid bone resection, as well as postoperatively to calculate the proportion of the glenoid bone actually resected.

RESULTS

Significantly decreased translations were observed in the shoulders with the QTB sling compared to the intact joint and the glenoid bone loss model. No significant differences in maximum external rotation were observed between the three different conditions.

CONCLUSION

This biomechanical study revealed a significant stabilizing effect of the arthroscopic subscapular QTB graft sling procedure in human shoulder cadavers without compromising external rotation. Clinical trials may reveal the usefulness of this experimental method.

Reconstruction of the Coracoacromial Ligament during a Modified Latarjet Procedure for the Treatment of Shoulder Instability: Clinical Outcome at Minimum 5 Years Follow-Up

OBJECTIVE

The function of the coracoacromial ligament (CAL) in superior shoulder stability has been well established, and the release of the CAL with the Latarjet procedure leads to increased superior humeral translation. A surgical technique was developed recently to reconstruct the CAL during a modified Latarjet procedure, and the clinical outcome of this technique at medium-term follow-up is yet to be determined.

METHODS

Twenty-six patients with chronic post-traumatic anterior shoulder instability were included in this retrospective case-control study. Patients in group 1 (n = 12) were surgically treated with the classic congruent-arc Latarjet, where the CAL is sacrificed. In group 2 (n = 14), the CAL was reconstructed using a pectoralis minor fascia flap (PMFF). Primary outcomes were the return to sports activity and functional assessment based on the Western Ontario Shoulder Instability Index (WOSI) and the Constant Score (CS) at minimum 5 years follow-up. Patient's demographics, sport activities, duration of surgery, the rate of recurrent dislocations, and specific complications related to the surgical technique were recorded as secondary variables.

RESULTS

There was a decrease of the WOSI in both groups, indicating a decrease of symptoms at follow-up compared to the preoperative level. There was no statistically significant difference between groups 1 and 2 for the total WOSI as well as for all subscales. There was an increase of the CS in both groups in all four items at follow-up compared to preoperatively, indicating an increase in shoulder function at follow-up. There was a statistically significant difference between groups 1 and 2 for the total CS, as well as for the items power, mobility, and activity, but not for pain. Most patients (n = 20) returned to their preoperative sports activity, 13 at the same level. However, seven patients who used to perform their sports competitively chose to perform their activity at a noncompetitive level after the Latarjet procedure. All were younger than 35 years of age. Six patients did not return to their preoperative sports activity. All except one were over 35 years of age. The duration of surgery ranged from 75 to 125 minutes with a mean ± SD of 94.23 ± 15.06 minutes for both groups with no significant difference between the groups (p = 0.117). None of the patients had intra- or postoperative complications related to the surgical procedure. Especially, no patient had recurrent dislocations of the affected shoulder following the Latarjet procedure.

CONCLUSION

The use of a PMFF is a safe technique for reconstruction of the CAL, which does not result in a longer surgery time or higher rate of complications. The reconstruction of the CAL during the modified Latarjet procedure may lead to better functional results in medium-term follow-up.

The novel arthroscopic subscapular sling procedure grants better stability than an arthroscopic Bankart repair in a cadaveric study

PURPOSE

This novel arthroscopic subscapular sling procedure stabilizes the shoulder using a semitendinosus graft to create a sling around the subscapular tendon, which provides both static and dynamic stability. The aim of the study was to evaluate the biomechanical stability of the subscapular sling procedure in human cadaveric shoulders. The hypothesis was that the sling offers an equal stabilizing effect and range of motion compared to an arthroscopic Bankart repair.

METHODS

Sixteen shoulders were investigated using an industrial robot-based testing platform and four different conditions: the physiologically intact shoulder, after creating a Bankart lesion, after arthroscopic Bankart repair, and finally after applying the subscapular sling procedure using a semitendinosus tendon graft. Joint translation and external rotation were evaluated for each condition.

RESULTS

The results show improved stability in the shoulders with the subscapular sling. The robot testing revealed a significant reduction in translation in anterior and anterior-inferior directions compared to the arthroscopic Bankart repair. None of the shoulders were dislocated by forced manual abduction and external rotation. No difficulties were encountered in performing the arthroscopic subscapular sling procedure. Thorough postoperative anatomical dissection showed no alterations to structures at risk.

CONCLUSION

The biomechanical results show increased stability with the use of the subscapular sling method.

Effect of rotator cuff muscle activation on glenohumeral kinematics: A cadaveric study

Healthy shoulder function requires the coordination of the rotator cuff muscles to maintain the humeral head's position in the glenoid. While glenohumeral stability has been studied in various settings, few studies have characterized the effect of dynamic rotator cuff muscle loading on glenohumeral translation during shoulder motion. We hypothesize that dynamic rotator cuff muscle activation decreases joint translation during continuous passive abduction of the humerus in a cadaveric model of scapular plane glenohumeral abduction. The effect of different rotator cuff muscle activity on glenohumeral translation was assessed using a validated shoulder testing system. The Dynamic Load profile is a novel approach, based on musculoskeletal modeling of human subject motion. Passive humeral elevation in the scapular plane was applied via the testing system arm, while the rotator cuff muscles were activated according to the specified force profiles using stepper motors and a proportional control feedback loop. Glenohumeral translation was defined according to the International Society of Biomechanics. The Dynamic load profile minimized superior translation of the humeral head relative to the conventional loading profiles. The total magnitude of translation was not significantly different (0.805) among the loading profiles suggesting that the compressive forces from the rotator cuff primarily alter the direction of humeral head translation, not the magnitude. Rotator cuff muscle loading is an important element of cadaveric shoulder studies that must be considered to accurately simulate glenohumeral motion. A rotator cuff muscle activity profile based on human subject muscle activity reduces superior glenohumeral translation when compared to previous RC loading profiles.

Does Arthroscopic Suture-Spanning Augmentation of Single-Row Repair Reduce the Retear Rate of Massive Rotator Cuff Tear?

BACKGROUND

Several surgical techniques have been proposed for massive rotator cuff tears (MRCTs), but the failure rates remain high. The suture-spanning augmentation technique of single-row (SSA-SR) repair was shown to reduce failure rates in cadaveric studies, but the outcome in vivo remains unclear.

PURPOSE

To determine if adding spanning sutures to SR repair during MRCT repairs can improve functional outcome and reduce failure rates.

STUDY DESIGN

Randomized controlled trial; Level of evidence, 2.

METHODS

The study included 71 patients with a diagnosed MRCT. The study group (n = 35) received SSA-SR repair. The control (n = 36) received SR repair. The American Shoulder and Elbow Surgeons (ASES) score, Constant score, UCLA (University of California, Los Angeles) score, and visual analog scale for pain were assessed preoperatively and 24 months postoperatively. Magnetic resonance imaging was arranged at 6 months postoperatively to evaluate the rotator cuff.

RESULTS

At 6 months postoperatively, the overall retear rate was 31.0%. The retear rate was lower in the SSA-SR group (14.3%) than in the SR group (47.2%, P = .002). At 24 months, the SSA-SR group had markedly improved ASES, Constant, and UCLA scores in comparison with the SR group ( P < .05). Within both groups, all scores had significant improvement as compared with the preoperative status ( P < .05).

CONCLUSION

The SSA-SR repair technique showed improved functional and radiologic results. Based on the superior postoperative outcome of this technique, the SSA-SR repair technique can be a potential treatment option for MRCT repair.

REGISTRATION

NCT03609164 (ClinicalTrials.gov identifier).

The stabilization effect of the conjoint tendon in reverse total shoulder arthroplasty

BACKGROUND

Numerous factors determine stability of reverse total shoulder arthroplasty. The effect of the conjoint tendon in relation to stability remains unknown. In this biomechanical study, we evaluated the influence of the conjoint tendon on the anterior stability of reverse total shoulder arthroplasty with a hemispherical glenosphere and a glenosphere with 9 mm lateralisation.

METHODS

A reverse total shoulder arthroplasty was implanted in 6 human cadaveric shoulders. The anterior stability was evaluated using a shoulder simulator. Two conditions, intact and dissected conjoint tendon, and 2 component configurations, a hemispherical glenosphere and a glenosphere with 9 mm lateralisation, were tested in each specimen. Testing of anterior stability was performed in 30° and 60° of abduction, with 0° and 30° of external rotation in the glenohumeral joint.

FINDINGS

The conjoint tendon showed a significant influence on the anterior stability with a hemispherical glenosphere in 30° and 60° with neutral rotation (p = 0.028) as well as 30° abduction with 30° (p = 0.028) external rotation. The 9 mm lateralised glenosphere stabilized significantly reverse total shoulder arthroplasty with resected conjoint tendon compared to the hemispherical glenosphere with resected conjoint tendon (p = 0.028).

INTERPRETATION

In a biomechanical setting the conjoint tendon has a stabilizing influence on the anterior stability of the reverse total shoulder arthroplasty with a hemispherical glenosphere in an abducted arm position, but this stabilizing effect was not seen with the lateralised glenosphere. The single influence of the lateralisation of the glenosphere on anterior stability was shown in cases of resected conjoint tendon.

Arthroscopic Transfer of the Conjoined Tendon-Coracoid Tip Complex for Anterior Shoulder Instability

In the treatment of anterior shoulder instability, there are various conditions in which a sling effect is needed to enhance anterior stability. The traditional Bristow-Latarjet procedure provides a sling effect but destroys or does not purposely protect the coracoacromial (CA) arch, which may result in superior instability. To preserve the CA arch and create a sling to enhance the anterior-inferior side of the shoulder, we introduce an arthroscopic technique to transfer the conjoined tendon-coracoid tip complex (CTCTC) with the intention to keep the CA ligament intact to the utmost. The indications for CTCTC transfer are patients younger than 45 years who participate in competitive sports, require forceful external rotation and abduction movements of the shoulder, and/or have capsule-ligament insufficiency. The main steps of this procedure include detaching the CTCTC, fashioning the coracoid tip to obtain a coracoid pillar, braiding the CTCTC, creating a glenoid tunnel and socket, placing a guide suture through the glenoid tunnel and subscapularis, passing the CTCTC through the subscapularis and into the glenoid socket, and performing suspension fixation of the CTCTC.

Arthroscopic Transfer of the Long Head of the Biceps Brachii for Anterior Shoulder Instability

In the treatment of anterior shoulder instability, there are various conditions in which a sling effect is needed to enhance anterior stability. The traditional Latarjet procedure provides a sling effect but destroys the coracoacromial arch, which may result in superior instability. To preserve the coracoacromial arch and create a sling to enhance the anterior-inferior side of the shoulder, we introduce an arthroscopic technique to transfer the long head of the biceps (LHB) brachii. Indications of LHB transfer are patients younger than 45 years of age who participate in competitive sports, require forceful external rotation and abduction movement of the shoulder, and/or have capsule-ligament insufficiency, as well as patients 45 years o or older who have combined SLAP lesions (type II or IV). The main steps of this procedure include detaching the LHB, retrieving and braiding the LHB, creating a glenoid tunnel, placing a guide suture through the subscapularis and glenoid tunnel, passing the LHB through the subscapularis and into the glenoid tunnel, and suspension fixation of the LHB.

The Coracoacromial Ligament: Anatomy, Function, and Clinical Significance

The coracoacromial ligament (CAL) was first described as a pain generator by Dr Charles Neer in the early 1970s. Since that time, considerable controversy regarding CAL management during acromioplasty has persisted. This review aims to better understand the role of the CAL in shoulder physiology and pathology. Sixty-six articles from 1958 to 2016 were identified using an electronic search of PubMed, Cochrane Library, AccessMedicine, and MD Consult for case series as well as cohort and prospective studies. The authors used “coracoacromial ligament” and “coracoacromial veil” as medical subject headings (MeSH). In addition, reference lists from all identified articles were reviewed for studies that the search terms may have omitted. The CAL plays an important role in shoulder biomechanics, joint stability, and proprioception. Morphological variance of the CAL is evident throughout the literature. Age-dependent changes due to chronic stress and cellular degradation cause thickening and stiffening of the CAL that may contribute to a spectrum of shoulder pathology from capsular tightness to rotator cuff tear arthropathy and impingement syndrome. The CAL is an integral component of the coracoacromial arch. CAL release during acromioplasty remains controversial. Future clinical outcomes research should endeavor to advance the understanding of the CAL to refine clinical and intraoperative decision making regarding its management.

Anterior stability of the reverse shoulder arthroplasty depending on implant configuration and rotator cuff condition

INTRODUCTION

The aim of this study was to investigate the stabilizing influence of the rotator cuff as well as the importance of glenosphere and onlay configuration on the anterior stability of the reverse total shoulder replacement (RTSR).

MATERIALS AND METHODS

A reverse total shoulder replacement was implanted into eight human cadaveric shoulders, and biomechanical testing was performed under three conditions: after implantation of the RTSR, after additional dissection of the subscapularis tendon, and after additional dissection of the infraspinatus and teres minor tendon. Testing was performed in 30° of abduction and three rotational positions: 30° internal rotation, neutral rotation, and 30° external rotation. Furthermore, the 38-mm and 42-mm glenospheres were tested in combination with a standard and a high-mobility humeral onlay. A gradually increased force was applied to the glenohumeral joint in anterior direction until the RTSR dislocated.

RESULTS

The 42-mm glenosphere showed superior stability compared with the 38-mm glenosphere. The standard humeral onlay required significantly higher anterior dislocation forces than the more shallow high-mobility onlay. External rotation was the most stable position. Furthermore, isolated detachment of the subscapularis and combined dissection of the infraspinatus, teres minor, and subscapularis tendon increased anterior instability.

CONCLUSIONS

This study showed superior stability with the 42-mm glenosphere and the more conforming standard onlay. External rotation was the most stable position. Detachment of the subscapularis as well as dissection of the complete rotator cuff decreased anterior stability.

Technical concept and evaluation of a novel shoulder simulator with adaptive muscle force generation and free motion

The human shoulder is one of the most complex joints of the human body, and due to the high range of motion and the complex soft tissue apparatus prone to injuries. Surgical therapies and joint replacements often lead to unsatisfactory results. To improve the understanding of the complex biomechanics of the shoulder, experimental investigations have to be conducted. For this purpose a new shoulder simulator with an innovative muscle force generation was developed. On the basis of a modular concept six artificial pneumatic muscles were integrated to represent the functionally most important muscles of the shoulder joint, whereby a free and controlled movement of the humerus can be conducted. For each muscle individual setpoints for muscle length control based on a user defined shoulder movement for any artificial or cadaver specimen are created by manual motion “Teach-In”. Additional to muscle forces and lengths, optical tracking and a joint force measurement is used to enable different biomechanical studies of the shoulder joint. This paper describes the technical setup as well as the control strategy and first results of its experimental functional validation.

Combined effect of change in humeral neck-shaft angle and retroversion on shoulder range of motion in reverse total shoulder arthroplasty - A simulation study

BACKGROUND

We studied combined effect of change in humeral neck shaft angle and retroversion on shoulder ROM in reverse total shoulder arthroplasty using 3-dimensional simulations.

METHODS

Using a 3D model construct based on the CT scans of 3 males and a 3-dimensional analysis program, a humeral component of reverse total shoulder arthroplasty was implanted in 0°, 10°, 20°, 30°,40° retroversion and 135°, 145°, and 155° neck shaft angle. Total horizontal range of motion (sum of horizontal adduction and abduction) at 30° and 60° scaption, adduction in the scapular plane and IR behind the back were measured for various combinations of neck shaft angle and retroversion.

FINDINGS

Change in retroversion didn't show any effect on total horizontal range of motion. Total horizontal range of motion at both 30° and 60° scaption, showed maximum values at 135° neck shaft angle and minimum values at 155° neck shaft angle. With any combination of retroversion angles, adduction deficit was maximum at 155° neck shaft angle and no adduction deficit at 135° neck shaft angle. Every 10° decrease in neck shaft angle resulted in an average 10.4° increase in adduction. For every 10° increase in retroversion, there was loss of internal rotation behind the back up to at least one vertebral level.

INTERPRETATION

135° neck shaft angle resulted in maximum total horizontal range of motion both at 30° and 60° scaption regardless of retroversion angles. 135° neck shaft angle also reduced the chances of scapular impingement. Decrease in retroversion angle resulted in more amount of internal rotation behind the back.

Reconstruction of the coracoacromial ligament during a modified Latarjet procedure: a case series

Background

The coracoacromial ligament (CAL) is an important restraint to superior shoulder translation. CAL release with the Latarjet procedure leads to increased superior humeral translation. Therefore, a surgical technique was developed to reconstruct the CAL during a modified Latarjet procedure.

Methods

Between May 2010 and July 2011, six patients (five were male, one was female; age 23–41 years) with chronic post-traumatic anterior shoulder instability were treated surgically with a modified congruent-arc Latarjet procedure (modLAT) with additional reconstruction of the CAL using a newly developed procedure, the pectoralis minor fascia flap (PMFF). Clinical follow-up was performed for up to 36 months, and patients were evaluated using a Rowe score.

Results

All six patients experienced chronic, post-traumatic anterior shoulder instability and had experienced multiple re-dislocations after initial treatment. The preoperative assessment showed a defect of the anterior glenoid in three cases, and the mean Rowe score was 16.67 (5–25). Open modLAT with PMFF resulted in a stable shoulder function with no re-dislocations. The Rowe score increased from 77.5 (65–90) at 12 weeks to 95 (90–100) at 12 months and plateaued thereafter. Operative duration was 95 min (78–112 min), and there were no intra- or postoperative complications. All patients returned to their preoperative sports activity, three at the same level.

Conclusion

The PMFF is a safe technique for reconstruction of the CAL during a modLAT procedure. Patients had improved shoulder function and no re-dislocations after the surgery.

Stabilisation for the disrupted acromioclavicular joint using a braided polyester prosthetic ligament

PURPOSE

To report outcomes of 21 men who underwent stabilisation for the disrupted acromioclavicular joint (ACJ) using a braided polyester prosthetic ligament.

METHODS

21 men aged 23 to 76 (mean, 43) years underwent stabilisation for the disrupted ACJ of Rockwood type 3 (n=12), type 4 (n=1), and type 5 (n=8) using a braided polyester prosthetic ligament.

RESULTS

The mean time from injury to surgery was 6.8 (range, 0-19) months. The mean follow-up duration was 30 (range, 7-67) months. The mean Constant Score was 86.8 (range, 62-100), and the mean individualised Constant Score was 88.5 (range, 68-100). The mean Oxford Shoulder Score was 43.1 (range, 28-48). The mean abduction power of the operated side was 82% (range, 31%-97%) that of the normal side. 20 patients were satisfied with the procedure. One patient was dissatisfied who developed scapulothoracic bursitis. One patient required arthroscopic subacromial decompression for impingement. One patient sustained a redislocation following a fall at 6 weeks and declined further surgery.

CONCLUSION

The braided polyester prosthetic ligament achieved good outcome for patients undergoing stabilisation for the disrupted ACJ.

Reverse total shoulder arthroplasty: a biomechanical evaluation of humeral and glenosphere hardware configuration

BACKGROUND

Various reverse total shoulder arthroplasty (rTSA) implant options are available for the humeral and glenosphere components. This study used a cadaveric biomechanical shoulder simulator to evaluate how hardware configurations in 2 common rTSA systems affect (1) abduction/adduction range of motion (ROM), (2) rotational ROM, and (3) forces to elevate the arm.

METHODS

Seven pairs of shoulders were tested on a biomechanical shoulder simulator before and after rTSA implantation. The Aequalis Reverse Shoulder (Tornier, Edina, MN, USA) and the Reverse Shoulder Prosthesis (RSP; DJO Surgical, Austin, TX, USA) were implanted in opposing shoulders. Aequalis implant options included humeral polymer insert thickness and eccentricity and glenosphere tilt. RSP implant options included glenosphere diameter and lateralization, humeral shell offset, and polymer insert depth.

RESULTS

Both the RSP and Aequalis shifted the center of rotation inferior and medially compared with native shoulders (P < .001). Increased Aequalis insert thickness reduced adduction (P < .003) and internal/external (P < .028) passive ROM. The 10° inferiorly tilted glenosphere increased deltoid abduction forces (P < .032). In the RSP, smaller glenosphere diameter (P < .012), a semiconstrained humeral insert (P < .023), and a neutral humeral shell offset (P < .002) all decreased adduction deficit, whereas lateral glenosphere offset increased passive abduction ROM (P < .028). Increased humeral shell offset decreased passive internal/external rotation ROM (P < .050).

DISCUSSION

Hardware configurations in rTSA have different effects on passive ROM and deltoid forces required for abduction. Identifying these changes may guide surgical decision making during rTSA placement.

Biomechanical comparison of reverse total shoulder arthroplasty systems in soft tissue-constrained shoulders

BACKGROUND

Numerous studies have examined the biomechanics of isolated variables in reverse total shoulder arthroplasty. This study directly compared the composite performance of two reverse total shoulder arthroplasty systems; each system was designed around either a medialized or a lateralized glenohumeral center of rotation.

METHODS

Seven pairs of shoulders were tested on a biomechanical simulator. Center of rotation, position of the humerus, passive and active range of motion, and force to abduct the arm were quantified. Native arms were tested, implanted with a Tornier Aequalis or DJO Surgical Reverse Shoulder Prosthesis (RSP), and then retested. Differences from the native state were then documented.

RESULTS

Both systems shifted the center of rotation medially and inferiorly relative to native. Medial shifts were greater in the Aequalis implant (P < .037). All humeri shifted inferior compared with native but moved medially with the Aequalis (P < .001). Peak passive abduction, internal rotation, and external rotation did not differ between systems (P > .05). Both reverse total shoulder arthroplasty systems exhibited adduction deficits, but the RSP implant deficit was smaller (P = .046 between implants). Both systems reduced forces to abduct the arm compared with native, although the Aequalis required more force to initiate motion from the resting position (P = .022).

CONCLUSION

Given the differences in system designs and configurations, outcome variables were generally comparable. The RSP implant allowed slightly more adduction, had a more lateralized humeral position, and required less force to initiate elevation. These factors may play roles in limiting scapular notching, improving active external rotation by normalizing the residual rotator cuff length, and limiting excessive stress on the deltoid.

Results of arthroscopic partial repair of large retracted rotator cuff tears

PURPOSE

To evaluate the midterm results of partial rotator cuff repair using the Constant score and the acromiohumeral radiographic measurement.

METHODS

Thirty-eight patients with a mean age of 65 years and a large retracted rotator cuff tear (at least 2 tendons) were included in the study. Patients underwent clinical examination, standard radiography, and isometric strength testing at a mean follow-up of 47 months. The rotator cuff tears were classified as posterosuperior, anterosuperior, or global tears (≥3 tendons), and an arthroscopic partial repair was performed.

RESULTS

The mean Constant score significantly increased from 56 points before surgery to 71 points after surgery (P = .041); the mean age- and sex-adjusted Constant score significantly improved from 63% to 90% at a mean follow-up of 47 months after arthroscopic partial rotator cuff repair (P = .003); and the subcategories pain and activity significantly improved (P = .001, P = .014, respectively). The active range of motion improved from 133° of flexion and 111° of abduction before surgery to 163° of forward flexion and 156° of abduction after surgery (P < .001). However, the active range of external rotation decreased from 44° before surgery to 36° after surgery. Further, there was a trend toward a decrease in the mean acromiohumeral distance from 7.0 mm before surgery to 5.6 mm after surgery. The abduction strength did not significantly improve after surgery (4.2 kg before surgery and 4.8 kg after surgery; P = .116).

CONCLUSIONS

An arthroscopic partial repair of the rotator cuff is an effective tool to improve the Constant score by restoring active forward flexion and abduction and through pain relief. Further, we found that a pathologically decreased acromiohumeral distance cannot be reversed by a partial rotator cuff repair.

LEVEL OF EVIDENCE

Level IV, therapeutic case series.

A biomechanical assessment of superior shoulder translation after reconstruction of anterior glenoid bone defects: The Latarjet procedure versus allograft reconstruction

Background:

The coracoacromial ligament (CAL) is an important restraint to superior shoulder translation. The effect of CAL release on superior stability following the Latarjet is unknown; therefore, our purpose was to compare the effect of two Latarjet techniques and allograft reconstruction on superior instability.

Materials and Methods:

Eight cadaveric specimens were tested on a simulator. Superior translation was monitored following an axial force in various glenohumeral rotations (neutral, internal, and external) with and without muscle loading. Three intact CAL states were tested (intact specimen, 30% glenoid bone defect, and allograft reconstruction) and two CAL deficient states (classic Latarjet (classicLAT) and congruent-arc Latarjet (congruentLAT)).

Results:

In neutral without muscle loading, a significant increase in superior translation occurred with the classicLAT as compared to 30% defect (P = 0.046) and allograft conditions (P = 0.041). With muscle loading, the classicLAT (P = 0.005, 0.002) and the congruentLAT (P = 0.018, 0.021) had significantly greater superior translation compared to intact and allograft, respectively. In internal rotation, only loaded tests produced significant results; specifically, classicLAT increased translation compared to all intact CAL states (P < 0.05). In external rotation, only unloaded tests produced significant results with classicLAT and congruentLAT allowing greater translations than intact (P ≤ 0.028). For all simulations, the allograft was not significantly different than intact (P > 0.05) and no differences (P = 1.0) were found between classicLAT and congruentLAT.

Discussion:

In most simulations, CAL release with the Latarjet lead to increased superior humeral translation.

Conclusion:

The choice of technique for glenoid bone loss reconstruction has implications on the magnitude of superior humeral translation. This previously unknown effect requires further study to determine its clinical and kinematic outcomes.

[Open transosseous reconstruction of the rotator cuff: clinical outcome, influencing factors and complications]

BACKGROUND

Open transosseous rotator cuff reconstruction (RCR) still plays a prominent role in current treatment of rotator cuff tears. This study aimed to examine mid-term and long-term results of clinical outcome, determine influencing factors and analyze complications.

PATIENTS

This retrospective cohort study included 104 Patients following standardized open transosseous RCR. After a mean follow-up period of 38.3 months (range 12-71 months) 88 Patients (89 shoulders) were available for examination. The mean age of Patients at surgery was 57.1 years (range 29-83 years). Standardized clinical examination included sonography and assessment of the absolute, relative and intra-individual constant scores (CS(abs), CS(rel), CS(intra)), Oxford shoulder score (OSS), American shoulder and elbow surgeons' score (ASESS) and single assessment numeric evaluation score (SANES). The level of significance for analysis of variance (ANOVA) was set at p < 0.05 (95% confidence interval).

RESULTS

Mean values and standard deviations (σ) were: CS(abs) = 71 points (σ: 20.3), CS(rel) = 76 points (σ: 20.7), CS(intra) = 86 % (σ: 19.5), OSS(mod) = 77 points (σ: 20.6), ASESS = 73 points (σ: 23.3) and SANES = 72 % (σ: 22.0). Clinical results were superior when the complaints were initiated by trauma (p < 0.05). Patients with massive tears showed inferior results relative to all outcome measures (p < 0.05). Concomitant pathologies even without surgical relevance were associated with inferior outcome (p < 0.05). The factors surgeon, suture material and acromioplasty did not exert a significant influence. Revision surgery was required in 12 out of 89 (13.5 %) cases and re-ruptures occurred in 19.1%.

CONCLUSIONS

Objective and subjective clinical results following open transosseous RCR were comparable to those of previously described open and arthroscopic techniques. Results were superior when the complaints were initiated by trauma. Massive tears and concomitant pathologies even without surgical relevance were associated with inferior clinical outcome. Open or arthroscopic acromioplasty did not add further benefits. A standardized operative procedure led to reproducible results irrespective of the factor surgeon.

Effect of lateral offset center of rotation in reverse total shoulder arthroplasty: a biomechanical study

BACKGROUND

Lateral offset center of rotation (COR) reduces the incidence of scapular notching and potentially increases external rotation range of motion (ROM) after reverse total shoulder arthroplasty (rTSA). The purpose of this study was to determine the biomechanical effects of changing COR on abduction and external rotation ROM, deltoid abduction force, and joint stability.

MATERIALS AND METHODS

A biomechanical shoulder simulator tested cadaveric shoulders before and after rTSA. Spacers shifted the COR laterally from baseline rTSA by 5, 10, and 15 mm. Outcome measures of resting abduction and external rotation ROM, and abduction and dislocation (lateral and anterior) forces were recorded.

RESULTS

Resting abduction increased 20° vs native shoulders and was unaffected by COR lateralization. External rotation decreased after rTSA and was unaffected by COR lateralization. The deltoid force required for abduction significantly decreased 25% from native to baseline rTSA. COR lateralization progressively eliminated this mechanical advantage. Lateral dislocation required significantly less force than anterior dislocation after rTSA, and both dislocation forces increased with lateralization of the COR.

CONCLUSION

COR lateralization had no influence on ROM (adduction or external rotation) but significantly increased abduction and dislocation forces. This suggests the lower incidence of scapular notching may not be related to the amount of adduction deficit after lateral offset rTSA but may arise from limited impingement of the humeral component on the lateral scapula due to a change in joint geometry. Lateralization provides the benefit of increased joint stability, but at the cost of increasing deltoid abduction forces.

Effect of deltoid tension and humeral version in reverse total shoulder arthroplasty: a biomechanical study

BACKGROUND

No clear recommendations exist regarding optimal humeral component version and deltoid tension in reverse total shoulder arthroplasty (TSA).

MATERIALS AND METHODS

A biomechanical shoulder simulator tested humeral versions (0°, 10°, 20° retroversion) and implant thicknesses (-3, 0, +3 mm from baseline) after reverse TSA in human cadavers. Abduction and external rotation ranges of motion as well as abduction and dislocation forces were quantified for native arms and arms implanted with 9 combinations of humeral version and implant thickness.

RESULTS

Resting abduction angles increased significantly (up to 30°) after reverse TSA compared with native shoulders. With constant posterior cuff loads, native arms externally rotated 20°, whereas no external rotation occurred in implanted arms (20° net internal rotation). Humeral version did not affect rotational range of motion but did alter resting abduction. Abduction forces decreased 30% vs native shoulders but did not change when version or implant thickness was altered. Humeral center of rotation was shifted 17 mm medially and 12 mm inferiorly after implantation. The force required for lateral dislocation was 60% less than anterior and was not affected by implant thickness or version.

CONCLUSION

Reverse TSA reduced abduction forces compared with native shoulders and resulted in limited external rotation and abduction ranges of motion. Because abduction force was reduced for all implants, the choice of humeral version and implant thickness should focus on range of motion. Lateral dislocation forces were less than anterior forces; thus, levering and inferior/posterior impingement may be a more probable basis for dislocation (laterally) than anteriorly directed forces.

Does a critical rotator cuff tear stage exist?: a biomechanical study of rotator cuff tear progression in human cadaver shoulders

BACKGROUND

It is unknown at which stage of rotator cuff tear the biomechanical environment is altered. The purpose of this study was to determine if a critical rotator cuff tear stage exists that alters glenohumeral joint biomechanics throughout the rotational range of shoulder motion, and to evaluate the biomechanical effect of parascapular muscle-loading.

METHODS

Eight cadaver shoulders were used with a custom testing system. Four progressive rotator cuff tear stages were investigated on the basis of footprint anatomy. Three muscle-loading conditions were examined: rotator cuff only; rotator cuff with deltoid muscle; and rotator cuff, deltoid, pectoralis major, and latissimus dorsi muscles. Testing was performed in the scapular plane with 0°, 30°, and 60° of shoulder abduction. The maximum internal and external rotations were measured with 3.4 Nm of torque. The position of the humeral head apex with respect to the glenoid was calculated with use of a MicroScribe 3DLX digitizing system throughout the rotational range of motion. The abduction capability was determined as the abduction angle achieved with increasing deltoid load.

RESULTS

Tear of the entire supraspinatus tendon significantly increased maximum external rotation and significantly decreased abduction capability with higher deltoid loads (p < 0.05). Tear of the entire supraspinatus tendon and half of the infraspinatus tendon significantly shifted the humeral head apex posteriorly at the midrange of rotation and superiorly at maximum internal rotation (p < 0.05). Loading the pectoralis major and latissimus dorsi muscles decreased the amount of humeral head elevation due to deltoid loading.

CONCLUSIONS

Tear of the entire supraspinatus tendon was the critical stage for increasing rotational range of shoulder motion and for decreased abduction capability. Further tear progression to the infraspinatus muscle was the critical stage for significant changes in humeral head kinematics. The pectoralis major and latissimus dorsi muscles played an important role in stabilizing the humeral head as the rotator cuff tear progressed.

The biomechanical effect of specific labral and capsular lesions on posterior shoulder instability

PURPOSE

In contrast to anterior shoulder instability there seems to be no single key lesion in posterior shoulder instability. Therefore, the purpose of this study was to determine the biomechanical effect of specific posterior capsulolabral lesions. Our hypothesis was that a posterior capsule lesion will have a predominant effect compared to a labrum detachment (Bankart lesion).

METHODS

Stability testing of 16 cadaveric human shoulders was performed. The specimens were distributed to two groups: the labrum lesion group and the capsular lesion group. In the labrum lesion group three different conditions were tested consecutively: posteroinferior Bankart lesion, additive pHAGL lesion, additive posterosuperior Bankart lesion. In the capsular lesion group two conditions were tested: posteroinferior capsule cut including a glenoidal transection of the pIGHL, additive rotator interval and superior capsule lesion (SGHL and CHL cut). All lesions were set arthroscopically. Biomechanical testing was performed in two positions: the sulcus-test position and the jerk-test position each with a passive humerus load of 50 N in the posterior, posteroinferior and inferior direction.

RESULTS

A posteroinferior Bankart lesion resulted in a percentage increase of 86% posterior translation in the jerk position and an increase of 31% inferior translation in the sulcus position. An additional pHAGL lesion resulted in a significant increase of posterior and inferior translation given by 31 and 41% in the jerk position. Regarding the capsular lesions, a cut of the posteroinferior capsule and the pIGHL resulted in a significant increased inferior translation of 53% in the sulcus position but did not cause a significant increase of posterior translation in the jerk position. If an additional rotator interval lesion is set the inferior translation is again significantly increased.

CONCLUSIONS

On the basis of our results traumatic posterior shoulder instability must be suspected to be bidirectional posteroinferior independently if a posterior capsule lesion or a posterior Bankart lesion is evident.

CLINICAL RELEVANCE

Capsular and labral lesions both have a significant biomechanical effect but differ in the predominant direction of instability, which is posterior for the Bankart lesion and inferior for the capsular lesion. An additional pHAGL or rotator interval lesion aggravates the posteroinferior instability and must be respected in the surgical treatment strategy.

Reversed arthroscopic subacromial decompression for symptomatic irreparable rotator cuff tears: mid-term follow-up results in 34 shoulders

BACKGROUND

In the elderly, there is no guideline for the treatment of irreparable rotator cuff lesions. The results of open or arthroscopic repair are variable. We hypothesized that the use of a reversed arthroscopic subacromial decompression (RASD) would yield comparable results.

MATERIAL AND METHODS

Between January 2004 and December 2006, thirty-eight patients underwent a RASD for irreparable cuff tears in 39 shoulders. The surgical procedure consisted of a tenotomy of the long head of the biceps tendon, a debridement of the torn rotator cuff and a tuberoplasty, without violation of the coracoacromial arch and the acromion.

RESULTS

Thirty-three patients (age 69.9 +/- 7.3 years) were available for clinical and radiological evaluation of 34 shoulders (male/female ratio: 11/22), at a mean follow-up of 38 months (range: 21 months-52 months). Two of 33 patients had required revision surgery, and were excluded from further statistical analysis. In the remaining 31 patients (32 shoulders), the modified Constant-Murley score (CMS) improved from 34.9% +/- 11.6 to 84.0% +/- 11.6 (p < 0.0001). The preoperative mobility did not correlate with the final result. Preoperative pain was found to correlate negatively to the modified CMS at follow-up (p= 0.0038). Although the acromiohumeral height decreased with 2.58 mm +/- 1.68 and the severity of glenohumeral osteoarthritis increased with one grade (Samilson-Prieto classification), there was no correlation with the functional outcome.

CONCLUSION

We conclude that for irreparable rotator cuff tears in the elderly, excellent mid-term results can be achieved with a RASD.

[Unstable shoulder dislocation]

Shoulder dislocations are a frequent event and the severity is often underestimated. A thorough clinical investigation and adapted imaging diagnostics are able to detect age-dependent injury patterns. A biphasic conservative treatment keeping the arm in a neutral to mild external rotation for 3 weeks has proven to be most effective and should be followed by an intensive physiotherapy. Nevertheless, conservative treatment protocols show unacceptable recurrence rates particularly in young men active in sport, therefore, surgical stabilisation is recommended. In the past open procedures were accepted as the gold standard, but today arthroscopic Bankart repair using suture anchors shows comparable recurrence rates. However, the clinical outcome with respect to the shoulder function is much better without compromising the subscapularis muscle.