Increased Glenohumeral Joint Loads Due to a Supraspinatus Tear Can Be Reversed With Rotator Cuff Repair: A Biomechanical Investigation

PURPOSE

To evaluate the effect of an isolated full-thickness supraspinatus (SSP) tear on glenohumeral kinematics and contact mechanics, as well as to quantify improvement following rotator cuff repair (RCR).

METHODS

Ten fresh-frozen cadaveric shoulders (mean age: 63.1 ± 4.6 years) were tested using a dynamic shoulder simulator. A pressure-mapping sensor was placed between the humeral head and the glenoid. Each specimen underwent the following three conditions: 1) native, 2) isolated full-thickness SSP tear, and 3) RCR. Maximum abduction angle (MAA) and superior humeral head migration (SHM) were measured using 3D motion tracking software. Cumulative deltoid force (CDF) and glenohumeral contact mechanics, including contact area (GCA) and contact pressure (GCP), were assessed at the resting position, as well as at 15°, 30°, 45°, and 60° of glenohumeral abduction.

RESULTS

Compared to native, the SSP tear resulted in a significant decrease in MAA (Δ-8.3°; P < .001) along with a SHM of 6.4 ± 3.8 mm, while significantly increasing CDF (Δ20.5 N; P = .008), GCP (Δ63.1 kPa; P < .001), and peak GCP (Δ278.6 kPa; P < .001), as well as decreasing GCA (Δ-45.8 mm²; P < .001) at each degree of abduction. RCR reduced SHM to 1.2 ± 2.5 mm, while restoring native MAA, CDF (Δ1.8 N), GCA (Δ4.5 mm²), GCP (Δ-4.5 kPa) and peak GCP (Δ19.9 kPa) at each degree of abduction (P > .999, respectively).

CONCLUSION

In a dynamic biomechanical cadaveric model, increased glenohumeral joint loads due to a full-thickness SSP tear can be reversed with RCR. More specifically, RCR restored native glenohumeral contact area and contact pressure, while preventing superior humeral head migration and decreasing compensatory deltoid forces.

CLINICAL RELEVANCE

These time 0 observations indicate that undergoing rotator cuff repair may prevent the development of degenerative changes by significantly reducing glenohumeral joint loads and ensuring sufficiently stable joint kinematics.

Utility of Preoperative Shear-Wave Elastography of the Supraspinatus Muscle for Predicting Successful Rotator Cuff Repair: A Prospective Observational Study With MRI Correlation

BACKGROUND. After rotator cuff tear, properties of the torn muscle predict failed surgical repair. OBJECTIVE. The purpose of our study was to explore the utility of preoperative shear-wave elastography (SWE) measurements of the supraspinatus muscle to predict successful rotator cuff repair, including comparison with MRI-based measures. METHODS. This prospective study included 74 patients (37 men, 37 women; mean age, 63.9 ± 10.0 [SD] years) who underwent rotator cuff repair between May 2019 and January 2021. Patients underwent preoperative clinical shoulder MRI and investigational shoulder ultrasound including SWE using shear modulus. The mean elasticity values of the supraspinatus and trapezius muscles were measured, and the elasticity ratio (i.e., ratio of mean elasticity of supraspinatus muscle to mean elasticity of trapezius muscle) was calculated. The muscular fatty infiltration score (1-3 scale) was recorded on gray-scale ultrasound. On MRI, muscular fatty infiltration was assessed by Goutallier grade (0-4 scale), and muscular atrophy was assessed by the occupation ratio (ratio of cross-sectional areas of supraspinatus muscle and supraspinatus fossa) and by the muscle atrophy grade (0-3 scale). After rotator cuff repair, the surgeon classified procedures as achieving sufficient (n = 60) or insufficient (n = 14) repair. RESULTS. Patients with insufficient repair, versus those with sufficient repair, more commonly exhibited a large (3-5 cm) tear (100.0% vs 50.0%). Patients with insufficient, versus sufficient, repair exhibited higher mean Goutallier grade (3.8 ± 0.4 vs 1.9 ± 1.1), mean muscle atrophy grade (2.0 ± 0.8 vs 0.5 ± 0.7), mean supraspinatus elasticity (44.15 ± 8.06 vs 30.84 ± 7.89 kPa), mean elasticity ratio (3.66 ± 0.66 vs 1.83 ± 0.58), and mean gray-scale fatty infiltration grade (2.86 ± 0.36 vs 1.63 ± 0.66) and showed lower mean occupation ratio (0.3 ± 0.1 vs 0.6 ± 0.1) (all, p < .001). AUC for predicting insufficient repair was 0.945 for Goutallier grade, 0.961 for occupation ratio, 0.900 for muscle atrophy grade, 0.874 for mean elasticity, 0.971 for elasticity ratio, and 0.912 for gray-scale fatty infiltration grade. Elasticity ratio (cutoff ≥ 2.51) achieved sensitivity of 100.0% and specificity of 90.0% for insufficient repair. At multivariable analysis including tear size, the three MRI measures, elasticity ratio, and gray-scale fatty infiltration grade, the only independent predictors of insufficient repair were muscle atrophy grade of 2-3 (odds ratio [OR] = 9.3) and elasticity ratio (OR = 15.7). CONCLUSION. SWE-derived elasticity is higher in patients with insufficient rotator cuff repair; the elasticity ratio predicts insufficient repair independent of tear size and muscle characteristics. CLINICAL IMPACT. Preoperative SWE may serve as a prognostic marker in patients with rotator cuff tear.

Advantages of 3-dimensional Measurements for Supraspinatus Intramuscular Fatty Evaluation in Patients With Medium to Massive Rotator Cuff Tears: Comparison With a Single Sagittal Slice

BACKGROUND

Fatty infiltration of the rotator cuff muscles is highly related to poor outcomes after rotator cuff tears. Fat fraction (FF) based on traditional 2-dimensional measurements (2D-FF) from a single sagittal Y-view slice cannot determine intramuscular FF in the rotator cuff muscles; the newly developed 3-dimensional method (3D-FF) is supposed to precede 2D measurements for intramuscular FF evaluation in accuracy and reliability.

PURPOSE

(1) To measure 3D-FF and (2) to compare 3D-FF and 2D-FF in terms of quantitative values and intra- and interobserver agreement.

STUDY DESIGN

Cohort study (diagnosis); Level of evidence, 2.

METHODS

Six-point Dixon magnetic resonance imaging was performed in patients with full-thickness supraspinatus tears. 2D-FF was calculated on a single sagittal Y-view. Semiautomatic segmentation software (ITK-SNAP) was used to reconstruct 3D volumes of the supraspinatus muscle and fat. 3D-FF was obtained by dividing the fat volume by the total volume of the supraspinatus muscle. A paired t test was used to compare the individual differences between 2D-FF and 3D-FF results. Linear regression and Bland-Altman analyses were performed to determine the agreement between 2D-FF and 3D-FF. Intraclass correlation coefficients (ICCs) were calculated to determine intra- and interobserver agreement.

RESULTS

The 3D muscular and fatty models presented an inhomogeneous distribution of intramuscular fat in the supraspinatus, indicating the superiority of 3D-FF over 2D-FF in capturing all muscle morphologic information. 2D-FF was significantly higher than 3D-FF in the supraspinatus with large (19.5% ± 5.9% vs 16.2% ± 3.7%; P = .002) and massive (34.8% ± 13.3% vs 26.2% ± 9.4%; P < .001) rotator cuff tears. 2D-FF overestimated the FF compared with 3D-FF by >50% in 14.7% of all patients and by >15% in 67.6% of patients with large or massive RCTs. The discrepancy between 2D-FF and 3D-FF increased with increasing mean FF. The intra- and interobserver agreement of 3D-FF (ICCs, 0.89-0.99 and 0.89-0.95) was superior to that of 2D-FF (ICCs, 0.71-0.95 and 0.64-0.79).

CONCLUSION

3D-FF indicated an inhomogeneous distribution of intramuscular fat by capturing all muscle and fat morphologic information. In patients with large and massive rotator cuff tears, 2D-FF of the supraspinatus was significantly higher than 3D-FF. 3D-FF was more reliable than 2D-FF for estimating fatty infiltration in the supraspinatus, with better intra- and interobserver agreement.

Does the Interval Slide Procedure Reduce Supraspinatus Tendon Repair Tension?: A Biomechanical Cadaveric Study

Background

The benefits of the interval slide (IS) procedure in retracted rotator cuff tears remain controversial.

Purpose

The purpose was to evaluate the effect of the IS procedure on repair tension (RT). It was hypothesized that the IS procedure (anterior IS [AIS], posterior IS [PIS], and intra-articular capsular release [CR]) would reduce the RT of a supraspinatus tendon.

Study Design

Controlled laboratory study.

Methods

A total of 31 Thiel-embalmed human cadaveric shoulders (mean age, 74 years; range, 68-84 years) were tested. Full-thickness supraspinatus tendon tears were created, and 1 cm of tendon was resected to simulate a retracted defect. Shoulders were randomized into intervention (n = 16) and control (n = 15) groups. In all shoulders, the load during tendon reduction to footprint was measured, an endpoint was defined as maximum tendon lateralization before 50 N was reached, and the RT (load during lateralization to endpoint) of the native tendon (t₁) was evaluated. In the intervention group, AIS (t₂), PIS (t₃), and CR (t₄) were performed in order, with RT measurement after each step. In the control group, RT was assessed at the same time points without the intervention.

Results

A complete reduction of the tendon was not achieved in any of the shoulders. Mean maximum lateralization was 6.7 ± 1.30 mm, with no significant differences between groups. In the intervention group, the overall IS procedure reduced RT about 47.0% (t₁ vs t₄: 38.7 ± 3.9 vs 20.5 ± 12.3 N; P < .001). AIS reduced RT significantly (t₁ vs t₂: 38.7 ± 3.9 vs 27.4 ± 10.5 N; P < .001), whereas subsequent PIS (t₂ vs t₃: 27.4 ± 10.5 vs 23.2 ± 12.4 N; P = .27) and CR (t₃ vs t₄: 23.2 ± 12.4 vs 20.5 ± 12.3 N; P = .655) did not additionally reduce tension. Comparison between groups at t₄ revealed a reduction of RT of about 47.8% (control vs intervention: 39.3 ± 4.0 vs 20.5 ± 12.3 N; P < .001).

Conclusion

The IS procedure reduces RT of the supraspinatus tendon in human cadaveric shoulders. However, performing PIS and CR subsequent to AIS does not reduce tension additionally.

Clinical Relevance

These findings provide surgeons with a biomechanical rationale regarding the efficacy of the IS procedure.

Case report: pulsed radiofrequency surgery combined with platelet-rich plasma injection in the treatment of supraspinatus injury

RATIONALE

The shoulder joint is the most movable joint of the human body, and the incidence of aseptic inflammation of the muscles and tendons around the shoulder joint and acute and chronic muscle injuries is relatively high. Pulsed radiofrequency neuromodulation technology is gradually being used in shoulder joint diseases. Platelet-rich plasma (PRP) is a high-power platelet plasma solution obtained by centrifugation of autologous blood. Platelet cells contain many growth factors that promote tissue repair.

PATIENT CONCERNS

Shoulder soreness, limited movement of the shoulder joint, abduction of the upper limbs, and aggravation of pain during flat lifting. The pain radiates to the deltoid muscle stop and forearm.

INTERVENTIONS

In this study, radiofrequency pulses combined with PRP were used to treat supraspinatus muscle injury and explore new methods for the treatment of shoulder joint muscle and tendon injuries represented by supraspinatus muscle injury.

DIAGNOSIS

We reported 4 patients with supraspinatus injury who received radiofrequency pulse combined with PRP treatment in our hospital.

OUTCOMES

After treatment, the patients were followed up at the first month, the third month, and the sixth month, and the Constant-Murley shoulder score and visual analog scale were used to comprehensively evaluate the postoperative improvement of the patients. There was no significant increase in postoperative pain, the Constant-Murley shoulder Score was significantly increased, the range of movement of the shoulder joint was significantly improved, and there were no postoperative complications.

LESSONS

The combined application of the 2 treatments can make full use of the analgesic effect of pulsed radiofrequency technology and the repairing effect of PRP, and can maximize the advantages of the 2 more advanced treatment methods in the field of minimally invasive.

Delamination in rotator cuff tears: Explanation of etiology through anatomical dissection

The prognostic significance of delaminated rotator cuff tears remains controversial. However, as the surgical goal is to maximize the contact area between layers, the macroscopic appearance of partial delaminated rotator cuff tears is essential. The aim of this anatomical study was to investigate the morphology of delaminated rotator cuff tears. We hypothesized that delamination zones at the intersection of the supraspinatus and infraspinatus tendon fibers are the origin of articular-side degenerative rotator cuff tears. Forty anatomical specimens were evaluated in this study. The supraspinatus and infraspinatus muscles were dissected, the origins were meticulously worked out and followed to their insertions at the humeral head. Fiber exchanges, overlays and delamination zones between the supraspinatus and infraspinatus muscles were photographically documented and measured. Delamination of rotator cuff tears can be classified into articular-side and bursal-side tears. The articular-layer consists of capsuloligamentous tissue, which included the rotator-cable/rotator-crescent complex, the joint capsule and a small part of the supraspinatus tendon. The bursal-side layer represents the tendinous tissue, which consists of the parallel, tendinous parts of the supraspinatus and infraspinatus muscles. Delamination of rotator cuff tears can be classified into articular-side and bursal-side tears. Present model of degenerative tears might explain the high prevalence of articular-side tears, which expand into the rotator-cable/rotator-crescent complex. It may be important for surgeons to incorporate these anatomical findings and considerations into the surgical planning.

Partial thickness tear of the supraspinatus at the musculotendinous junction in a softball catcher

We report a rare case of a partial thickness tear of the supraspinatus at the musculotendinous junction in a softball catcher. Preoperative magnetic resonance images of the shoulder showed high signal intensity areas at the musculotendinous junction, along with discontinuity of the articular side of the supraspinatus. Arthroscopic examination revealed articular-side partial tear at the musculotendinous junction. The patient was able to return to playing softball 20 weeks after arthroscopic side-to-side repair. J. Med. Invest. 68 : 386-388, August, 2021.

Effects of shoulder abduction on the stiffness of supraspinatus muscle regions in rotator cuff tear

This study aimed to compare the effect of the load of the upper limb on the stiffness of supraspinatus muscle regions during isometric shoulder abduction in the scapular plane in healthy individuals and patients with a rotator cuff tear. Thirteen male patients were scheduled for arthroscopic rotator cuff repair, and 13 healthy male individuals were recruited. The movement task involved 30° isometric shoulder abduction in the scapular plane. The tasks included passive abduction, abduction with half‐weight of the upper limb (1/2‐weight), and full weight of the upper limb (full‐weight). The stiffness of the supraspinatus muscle (anterior superficial, anterior deep, posterior superficial, and posterior deep regions) was recorded using ultrasound shear‐wave elastography. The stiffness of the anterior superficial region on the affected side was significantly lower than that on the control side for the 1/2‐weight and full‐weight tasks. The stiffness of the anterior deep, posterior superficial, and posterior deep regions was not affected. This is the first study that investigated the mechanical effects of different loads on different supraspinatus muscle regions in rotator cuff tear patients. Our results indicate that the anterior superficial region in rotator cuff tear patients was mainly responsible for reduced active stiffness. This might be because this region contributes to force exertion and exhibits atrophy in rotator cuff tears. Hence, the anterior superficial region could be a focal point of quantitative dysfunction evaluation of the supraspinatus muscle in the case of a rotator cuff tear.

Combining fascia lata autograft bridging repair with artificial ligament internal brace reinforcement : a novel healing-improvement technique for irreparable massive rotator cuff tears

AIMS

The aim of this study is to provide a detailed description of cases combining bridging patch repair with artificial ligament "internal brace" reinforcement to treat irreparable massive rotator cuff tears, and report the preliminary results.

METHODS

This is a retrospective review of patients with irreparable massive rotator cuff tears undergoing fascia lata autograft bridging repair with artificial ligament "internal brace" reinforcement technique between January 2017 and May 2018. Inclusion criteria were: patients treated arthroscopically for an incompletely reparable massive rotator cuff tear (dimension > 5 cm or two tendons fully torn), stage 0 to 4 supraspinatus fatty degeneration on MRI according to the Goutallier grading system, and an intact or reparable infraspinatus and/or subscapularis tendon of radiological classification Hamada 0 to 4. The surgical technique comprised two components: first, superior capsular reconstruction using an artificial ligament as an "internal brace" protective device for a fascia lata patch. The second was fascia lata autograft bridging repair for the torn supraspinatus. In all, 26 patients with a mean age 63.4 years (SD 6.2) were included.

RESULTS

All patients underwent more than two years of follow-up (mean 33.5 months (24 to 45)). All clinical scores were also improved at two-year follow-up (mean visual analogue scale 0.7 (SD 0.5) vs 6.1 (SD 1.2); p < 0.001; mean American Shoulder and Elbow Surgeons score 93.5 (SD 5.3) vs 42.5 (SD 10.8); p < 0.001; mean University of California, Los Angeles score, 31.7 (SD 3.7) vs 12.0 (SD 3.1); p < 0.001; and mean Constant-Murley score 88.7 (SD 3.5) vs 43.3 (SD 10.9); p < 0.001), and 24 of 26 fascia lata grafts were fully healed on MRI (92%). One patient had haematoma formation at the harvesting side of the fascia lata at two days postoperatively.

CONCLUSION

The fascia lata autograft bridging repair combined with artificial ligament internal brace reinforcement technique achieved good functional outcomes, with a high rate of graft healing at two-year follow-up. Although the short-term results are promising, further studies with a greater number of patients would provide clearer results. Cite this article: Bone Joint J 2021;103-B(10):1619-1626.

Relationship between glenohumeral internal rotation deficit and shoulder conditions in professional baseball pitchers

BACKGROUND

Previous studies have reported that glenohumeral internal rotation deficit (GIRD) may increase the risk of throwing-shoulder injuries. The purpose of this study was to analyze the conditions of the throwing shoulder in professional baseball pitchers with GIRD by comparing with those in pitchers without GIRD.

METHODS

In total, 26 male professional baseball pitchers participated in this study. We evaluated passive range of motion (ROM) and isometric muscle strength at internal rotation (IR) and external rotation (ER) at 90° of abduction, as well as the muscle thickness of the supraspinatus (SSP) and infraspinatus (ISP) by ultrasound. The pitchers were divided into 2 groups: those who exhibited a loss of IR of ≥20° in the throwing shoulder (GIRD group) and those who did not (non-GIRD group).

RESULTS

In the GIRD group, the total ROM deficit (throwing side - non-throwing side) (P < .001), the muscle thickness ratio (throwing to non-throwing) of the SSP and ISP (P = .017 and P = .014, respectively), and the muscle strength ratio (throwing to non-throwing) of ER (P = .028) were significantly lower than those in the non-GIRD group. In contrast, the muscle strength ratio (throwing to non-throwing) of IR was significantly higher in the GIRD group than in the non-GIRD group (P = .0064).

CONCLUSIONS

We have shown that GIRD has significant correlations with several conditions, such as atrophy of the SSP and ISP, weakness of ER strength, enhancement of IR strength, limitation of total ROM, and throwing side, all of which could be important factors for throwing-shoulder injuries.

Surgical rotator cuff muscle biopsies: are they representative of overall muscle quality?

BACKGROUND

Current research on human rotator cuff pathology relies on superficial biopsy specimens. It is unclear whether these biopsies are representative of overall muscle quality. The purpose of this study is to use magnetic resonance imaging with iterative decomposition of echoes of asymmetric length sequencing to investigate variability of fatty infiltration within the supraspinatus and infraspinatus muscle.

METHODS

We retrospectively identified 45 patients who underwent arthroscopic rotator cuff repair with preoperative iterative decomposition of echoes of asymmetric length imaging completed. The supraspinatus and infraspinatus were segmented on 4 consecutive slices, including the scapular Y, 2 slices medial, and 1 slice lateral. Intramuscular fat was measured in multiple regions for both supraspinatus (whole muscle, anterior, posterior, superficial band, anterior band, and posterior band) and infraspinatus (whole muscle, superior, inferior, superficial band, superior band, and inferior band). Comparisons of intramuscular fat were determined with Wilcoxon sign-rank tests. Analysis of variance was used to compare between the 4 consecutive slices. Significance was defined as P < .05.

RESULTS

Magnetic resonance imaging showed 31 full-thickness supraspinatus tears, 10 partial-thickness supraspinatus tears, and 4 intact supraspinatus tendons and 3 full-thickness infraspinatus tears, 2 partial-thickness infraspinatus tears, and 40 intact infraspinatus tendons. The anterior supraspinatus contained significantly higher fat content than the posterior supraspinatus (7.4% ± 7.4% vs. 5.4% ± 5.7%, P = .003). The superior and inferior halves of the infraspinatus were not different from each other (P = .11). The superficial band did not differ from the whole muscle in both supraspinatus (P = .14) and infraspinatus (P = .20). However, the anterior band of the supraspinatus had significantly more fat than the posterior band (8.2% ± 9.3% vs. 5.0% ± 5.7%, respectively, P < .0001), and the superior band of the infraspinatus had significantly more fat than the inferior band (5.2% ± 4.8% vs. 4.2% ± 5.3%, respectively, P = .03). There was no difference between all 4 medial and lateral slices in the supraspinatus (P = .92) and infraspinatus (P = .90).

CONCLUSION

Fat fractions within the supraspinatus and infraspinatus demonstrate significant spatial variability that may influence interpretation of local biopsy samples. Future biopsy studies may benefit from multiple samples between different specific locations.

Comparison of low level and high power laser combined with kinesiology taping on shoulder function and musculoskeletal sonography parameters in subacromial impingement syndrome: a Randomized placebo-controlled trial

Background: Subacromial impingement syndrome (SAIS) is a common cause of shoulder pain. The effects of physiotherapy modalities including low-level laser (LLL) and high power laser (HPL) on the SAIS have mostly been evaluated by the subjective outcome variables accompanied with the controversial findings and none of them has compared a combination of these two modalities, yet.Objectives: The present study was conducted to evaluate the effects of low-level laser (LLL) and high power laser (HPL) combined with kinesiology taping (KT), on the pain, function, and musculoskeletal ultrasound (MSKUS) parameters in the SAIS.Methods: Thirty patients with SAIS were randomly divided into the LLL-KT, HPL-KT, and sham-KT groups, respectively. Patients received seven treatment sessions. Visual analogue scale (VAS), shoulder pain and disability index (SPADI), MSKUS parameters were measured before and 48 hours after the treatment cessation.Results: Pain intensity significantly reduced in the LLL-KT (-2.43 (0.97)), HPL-KT (-3.43 (1.99)), and sham-KT (-2.43 (1.62)) (P < .01). All the SPADI subscales are significantly reduced in all the groups (P < .05), except for the pain in the sham-KT (P = .06). Significant improvements were only observed in the diameters of biceps (P < .05), supraspinatus tendon thickness in short and long axes (P < .05), occupation ratio (P = .004), and echogenicity (P = .03) in the HPL-KT. Although the acromiohumoral distance (AHD) significantly increased in all the groups including the sham-KT (P < .01), supraspinatus tendon thickness significantly decreased (P < .05), and echogenicity increased (P = .003) just in the HPL-KT.Conclusions: Kinesiology taping method alone is an effective intervention. Nevertheless, adding the analgesic and anti-inflammatory effects of both LLL and HPL to KT seems to result in better improvement of the pain, function, and MSKUS parameters in the SAIS. Findings of this study suggested that the HPL is more beneficial than the LLL or KT alone for management of the patients with SAIS.

Intratendinous Strain Variations of the Supraspinatus Tendon Depending on Repair Technique: A Biomechanical Analysis Regarding the Cause of Medial Cuff Failure

BACKGROUND

Double-row (DR) and transosseous-equivalent (TOE) techniques for rotator cuff repair offer more stability and promote better tendon healing compared with single-row (SR) repairs and are preferred by many surgeons. However, they can lead to more disastrous retear patterns with failure at the medial anchor row or the musculotendinous junction. The biomechanics of medial cuff failure have not been thoroughly investigated thus far.

PURPOSE

To investigate the intratendinous strain distribution within the supraspinatus tendon depending on repair technique.

STUDY DESIGN

Controlled laboratory study.

METHODS

Twelve fresh-frozen cadaveric shoulders were used. The intratendinous strain within the supraspinatus tendon was analyzed in 2 regions-(1) at the footprint at the greater tuberosity and (2) medial to the footprint up to the musculotendinous junction-using a high-resolution 3-dimensional camera system. Testing was performed at submaximal loads of 40 N, 60 N, and 80 N for intact tendons, after SR repair, after DR repair, and after TOE repair.

RESULTS

The tendon strain of the SR group differed significantly in both regions from that of the intact tendons and the TOE group at 40 N (P≤ .043) and from the intact tendons, the DR group, and the TOE group at 60 N and 80 N (P≤ .048). SR repairs showed more tendon elongation at the footprint and less elongation medial to the footprint. DR and TOE repairs did not provide significant differences in tendon strain when compared with the intact tendons. However, the increase in tendon strain medial to the footprint from 40 N to 80 N was significantly more pronounced in the DR and TOE group (P≤ .029).

CONCLUSION

While DR and TOE repair techniques more closely reproduced the strains of the supraspinatus tendon than did SR repair in a cadaveric model, they showed a significantly increased tendon strain at the musculotendinous junction with higher loads in comparison with the intact tendon.

CLINICAL RELEVANCE

DR and TOE rotator cuff reconstructions lead to a more anatomic tendon repair. However, their use has to be carefully evaluated whenever tendon quality is diminished, as they lead to a more drastic increase in tendon strain medial to the footprint, putting these repairs at risk of medial cuff failure.

Microfragmented Adipose Tissue With Adjuvant Platelet-Rich Plasma Combination Therapy for Partial-Thickness Supraspinatus Tear

A 50-year-old male presented with acute, sharp, right shoulder pain. Ultrasound of the right shoulder revealed a partial thickness tear of the supraspinatus. After conservative management failed to provide any relief, he was treated with microfragmented adipose tissue (MFAT) injection followed by platelet-rich plasma (PRP) at 14 weeks. At the 28-week follow-up, he showed significant improvement in pain and mobility with a resolution of the tear on ultrasound. While PRP has been shown to confer some protection against retears, very few studies have investigated the efficacy of MFAT use in rotator cuff pathology. In this case, we used a combination of MFAT and PRP to successfully treat a partial thickness supraspinatus tear. These agents may function in a synergistic manner, with MFAT providing a cell scaffold and PRP modulating the cellular environment to optimize healing. Further studies are needed to better understand the mechanism of this treatment modality in treating similar conditions.

Current concepts in the evolution of arthroscopic rotator cuff repair

Arthroscopic rotator cuff repair has become one of the most common and successful surgeries performed in orthopedics. It represents the culmination of advances in many diverse fields such as optics, fluid dynamics, mechanical engineering, and most recently, orthobiologics. This article reviews the current state of the art of arthroscopic rotator cuff repair, through the lens of its historical context and evolution to our present understanding. We review the limitations in the current approach, and glance toward the future of rotator cuff regeneration with emerging technologies.

Surgical Treatment Outcomes for Everted Bursal Flap of Delaminated Supraspinatus Tear

Background:

Although everted bursal flaps of delaminated tears have been reported, few studies have reported radiologic images, arthroscopic findings, and clinical results after repair.

Purpose:

To compare the repair outcomes of everted delaminated tears with those of classic delaminated supraspinatus tears.

Study Design:

Cohort study; Level of evidence, 3.

Methods:

Among 153 patients who underwent arthroscopic rotator cuff repair for a delaminated supraspinatus tear, everted bursal flap tears were observed in 24 patients upon arthroscopy (group A). Another 24 patients with classic delaminated supraspinatus tears, matched for age and sex, were selected for group B. Magnetic resonance imaging (MRI) and ultrasonography were performed preoperatively and postoperatively. Patients were evaluated using a visual analog scale (VAS) for pain as well as functional scores (American Shoulder and Elbow Surgeons [ASES] score, Constant score, and University of California Los Angeles shoulder score). Scores were compared preoperatively and at final follow-up (mean follow-up, 32 months).

Results:

Patients in both groups A and B reported improved VAS and functional scores at the final follow-up. In group A, preoperative VAS scores were higher and functional scores were poorer than in group B. Subacromial effusions with tendon swelling on preoperative MRI were more common in group A. During follow-up ultrasonography, group A patients exhibited persistent subacromial effusion. However, VAS scores at final follow-up were significantly better in group A (0.4 ± 0.7) than in group B (1.6 ± 1.4) (P < .001), and ASES scores at final follow-up were better in group A (84.3 ± 4.3) than in group B (77.0 ± 10.2) (P = .005).

Conclusion:

Everted bursal flap delaminated tears were associated with higher VAS scores and poorer functional scores preoperatively. Although subacromial effusions were experienced by group A during the early postoperative period, clinical outcomes at final follow-up were significantly better for everted delaminated tears compared with classic delaminated tears.

Differences in supraspinatus occupation ratio between the symptomatic, the contralateral asymptomatic shoulder and control subjects: A cross-sectional study

ABSTRACT

The relationship between supraspinatus tendon thickness and the acromiohumeral distance (AHD) at both rest position and shoulder elevation is still to be explored in those with chronic shoulder pain. The aim is to compare supraspinatus occupation ratio (OR) at 0° and 60° of shoulder elevation measured by ultrasound imaging in the symptomatic shoulder, the contralateral asymptomatic shoulder and in healthy subjects. This was across-sectional, observational study. A sample of 56 participants with subacromial pain syndrome in their dominant arm was recruited in 3 different primary care centres. Forty participants without shoulder pain were also recruited. The AHD at 0° and 60° of active shoulder abduction as well as the supraspinatus tendon thickness were measured by ultrasound in these groups. Supraspinatus OR at 60° was significantly greater in symptomatic compared to asymptomatic shoulders (P = .04) and healthy shoulders (P = .008). The percentage of change in supraspinatus OR from rest position to 60° was also greater in symptomatic shoulders when comparing with asymptomatic (P = .01) and healthy shoulders (P = .03). No other statistically significant differences for the rest of comparisons were found. Supraspinatus OR may explain shoulder pain in chronic conditions. Further studies at acute and chronic conditions after a physiotherapy treatment are needed to explore its usefulness in clinical practice.

Functional Evaluation of Levator Scapulae Tendon to Supraspinatus in Adult Brachial Plexus Injuries

Introduction  Brachial plexus injuries are severe life-altering injuries. The surgical method to restore shoulder abduction in adult upper brachial plexus injuries involves the usage of nerve grafts and nerve transfers targeting the suprascapular and/or the axillary nerve. When the primary nerve surgery has been unsuccessful or recovery has been incomplete or with a late presentation, muscle transfer procedures are needed to provide or improve shoulder abduction. Levator scapulae to supraspinatus is a transfer to improve shoulder abduction in posttraumatic brachial plexus injuries.

Material and Methods  The study included 13 patients with the age ranging from 17 to 47 years with a mean age of 30 years. All these patients had preop shoulder abduction of Medical Research Council (MRC) grade ≤3. All had a minimum of MRC grade 4 of active elbow flexion. Eleven patients had primary surgery. Only patients with a minimum of 1 year postoperative follow-up were included. All 13 patients underwent levator scapulae transfer only.

Results  All patients had a stable shoulder postoperatively. The average increase in active shoulder abduction was from 6.15°(median: 0°) preoperatively to 61.92°(median: 60°), with an average gain in shoulder abduction of 49.61°(median: 50°).

Conclusions  Transfer of levator scapulae tendon to the supraspinatus is an option to improve shoulder abduction in posttraumatic brachial plexus. In conditions where supraspinatus alone is not functioning, levator scapulae is the best available transfer, considering its strength and maintaining the form of the shoulder unlike trapezius transfer. In patients with previous surgery where supraspinatus has recovered partially but not functionally significant, this tendon transfer can be considered for the augmentation of the existing shoulder abduction.

Lateral to medial fibro-adipogenic degeneration are greater in infraspinatus than supraspinatus following nerve and tendon injury of murine rotator cuff

Small animal models of massive tears of the rotator cuff (RC) were introduced a decade ago and have been extensively used to study the pathophysiology of chronically injured RC. Transection of rodent suprascapular nerve and RC tendon results in progressive muscle atrophy, fibrosis and fat accumulation and affect the infraspinatus and supraspinatus muscles similarly to that seen in the setting of massive RC tears in humans. The purpose of this study was to perform a comprehensive and detailed analysis of the kinetics of fibrotic scar and adipose tissue development comparing phenotypic differences between chronically injured infraspinatus and supraspinatus. Automatic mosaic imaging was used to create large image of whole infraspinatus or supraspinatus sectioned area for quantification of spatial heterogeneity of muscle damage. Pathologic changes advanced from the lateral site of transection to the medial region far from the transection site. A prominent, accelerated muscle fibrosis and fat accumulation was measured in injured infraspinatus compared to supraspinatus. Furthermore, adipose tissue occupied significantly larger area than that of fibrotic tissue in both muscles but was greater in infraspinatus within 6 weeks post induction of injury. Our findings confirm that infraspinatus is more susceptible to accelerated chronic degeneration and can be used to identify the physiological functions that distinguish between the response of infraspinatus and supraspinatus in the setting of massive tears. Whether these pathologic differences observed in mice are reflected in humans is one key aspect that awaits clarification.

Spontaneous Intramuscular Abscesses Involving the Rotator Cuff Muscles in Two Cases Presenting During the COVID-19 Pandemic

Spontaneous abscesses involving the rotator cuff muscles are a rare surgical occurrence. Patients with such abscesses are often initially misdiagnosed or there is a significant diagnostic delay. Herein, we report one case of a spontaneous intramuscular abscess involving the subscapularis muscle and a second case of an abscess involving the supraspinatus muscle. There is a multitude of predisposing risk factors to developing an intramuscular abscess formation, which includes immunodeficiency, trauma, injection drug use, concurrent infection, and malnutrition. The most significant risk factor in our cases was poorly controlled type 2 diabetes mellitus. Poorly controlled diabetes is known to cause impaired clearance of pathogens, predisposing patients to abscess formation. Both patients also delayed presenting to the hospital due to concerns surrounding the coronavirus disease of 2019 (COVID-19) pandemic.

We describe the use of a deltoid-pectoral approach to access the subscapular abscess allowing surgical drainage. The supraspinatus abscess was drained by direct incision. We advocate utilising common and familiar approaches with or without arthroscopy where possible. These cases highlight the importance of early imaging in patients presenting with the physiological signs of infection and idiopathic shoulder pain.

[Supraspinatus tendon ruptures: correlation between MRI and surgical findings]

INTRODUCTION

In rotator cuff rupture, the supraspinatus tendon ranks first in frequency. MRI is the study of choice for preoperative diagnosis and planning. The objective of this study was to assess the concordance between findings observed with MRI and transoperative in patients with supraspinatus tendon rupture.

MATERIAL AND METHODS

A retrospective analysis was conducted from January 2014 to January 2020. Including patients over the age of 18, with MRI and supraspinatus tendon rupture report. A 2 analysis was performed for sensitivity, specificity, predictive values and diagnostic certainty using surgical findings as a reference. The kappa index was used to show the concordance between MRI and transoperative findings.

RESULTS

A total of 79 patients were included in the study, 45 male and 34 female. The average age was 52.14 years. MRI correctly diagnosed 60.76% of supraspinatus ruptures, showing 74% sensitivity and 96% specificity for complete ruptures. For partial ruptures I show a sensitivity of 96%, a specificity of 33%. The kappa index showed a match of 0.90 for total ruptures and 0.53 for partial.

CONCLUSIONS

MRI demonstrated good sensitivity and specificity for diagnosing complete ruptures, with good match to surgical findings. MRI proved to be a non-specific study for the identification of partial ruptures, which causes these lesions to be overdiagnosed.

Pregnancy and Lactation Impair Subchondral Bone Leading to Reduced Rat Supraspinatus Tendon-to-Bone Insertion Site Failure Properties

Pregnant women experience weight gain, gait changes, and biochemical fluctuations that impair joint function and alter the maternal skeleton. Hormonal changes increase pelvic ligament laxity in preparation for childbirth and affect peripheral joint laxity. Calcium demands also rise during pregnancy and lactation, resulting in reduced bone mineral density (BMD) and maternal bone loss. Altered tendon properties and bone loss during pregnancy and lactation may impact tendon insertion sites, such as rotator cuff tendons where insertion site ruptures are common. However, the effects of pregnancy and lactation at the tendon-to-bone interface have not been investigated. Therefore, the objective of this study was to evaluate supraspinatus tendon mechanical properties and insertion site microstructure during pregnancy, lactation, and postweaning recovery in female rats. We hypothesized that pregnancy and lactation would compromise supraspinatus tendon mechanical properties and subchondral bone microstructure. Female rats were divided into virgin, pregnancy, lactation, and recovery groups, and supraspinatus tendons were mechanically evaluated. Surprisingly, tendon mechanics was unaffected by pregnancy and lactation. However, tendon modulus decreased two-weeks postweaning. Additionally, tendons failed by bony avulsion at the insertion site, and the lactation group exhibited reduced failure properties corresponding to decreased subchondral bone mineralization. Lactation also resulted in dramatic bone loss at the epiphysis, but trabecular bone microarchitecture recovered postweaning. In conclusion, lactation following pregnancy impaired trabecular bone microstructure and subchondral bone mineralization, leading to reduced supraspinatus tendon-to-bone insertion site failure properties. These findings will contribute toward understanding the pathogenesis of tendon-to-bone disorders.

The new dynamic isotonic manipulation examination (DIME) is a highly sensitive secondary screening tool for supraspinatus full-thickness tears

BACKGROUND

Traditional shoulder physical examination (PE) tests have suboptimal sensitivity for detection of supraspinatus full-thickness tears (FTTs). Therefore, clinicians may continue to suspect FTTs in some patients with negative rotator cuff PE tests and turn to magnetic resonance imaging (MRI) for definitive diagnosis. Consequently, there is a need for a secondary screening test that can accurately rule out FTTs in these patients to better inform clinicians which patients should undergo MRI. The purpose of this study was to assess the ability of 2 new dynamic PE tests to detect supraspinatus pathology in patients for whom traditional static PE tests failed to detect pathology.

METHODS

We prospectively enrolled 171 patients with suspected rotator cuff pathology with negative findings on traditional rotator cuff PE, who underwent 2 new dynamic PE tests: first, measurement of angle at which the patient first reports pain on unopposed active abduction and, second, the dynamic isotonic manipulation examination (DIME). Patients then underwent shoulder magnetic resonance arthrogram. Data from the new PE maneuvers were compared with outcomes collected from magnetic resonance arthrogram reports.

RESULTS

Pain during DIME testing had a sensitivity of 96.3% and 92.6% and a negative predictive value of 96.2% and 94.9% in the coronal and scapular planes, respectively. DIME strength ≤86.0 N had a sensitivity of 100% and 96.3% and a negative predictive value of 100% and 95.7% in the coronal and scapular planes, respectively. Pain at ≤90° on unopposed active abduction in the coronal plane had a specificity of 100% and a positive predictive value of 100% for supraspinatus pathology of any kind (ie, tendinopathy, "fraying," or tearing).

CONCLUSION

DIME is highly sensitive for supraspinatus FTTs in patients with negative traditional rotator cuff PE tests for whom there is still high clinical suspicion of FTTs. Thus, this test is an excellent secondary screening tool for supraspinatus FTTs in patients for whom clinicians suspect rotator cuff pathology despite negative traditional static PE tests. Given its high sensitivity, a negative DIME test rules out supraspinatus FTT well in these patients, and can therefore better inform clinicians which patients should undergo MRI. In addition, the angle at which patients first report pain on unopposed active shoulder abduction is highly specific for supraspinatus pathology.

Graft Tensioning in Superior Capsular Reconstruction Improves Glenohumeral Joint Kinematics in Massive Irreparable Rotator Cuff Tears: A Biomechanical Study of the Influence of Superior Capsular Reconstruction on Dynamic Shoulder Abduction

Background:

Superior capsular reconstruction (SCR) for massive, irreparable rotator cuff tears has become more widely used recently; however, ideal tensioning of the graft and the influence on joint kinematics remain unknown.

Purpose/Hypothesis:

The purpose of this study was to assess the effects of graft tensioning on glenohumeral joint kinematics after SCR using a dermal allograft. The hypothesis was that a graft fixed under tension would result in increased glenohumeral abduction motion and decreased cumulative deltoid forces compared with a nontensioned graft.

Study Design:

Controlled laboratory study.

Methods:

A total of 10 fresh-frozen cadaveric shoulders were tested using a dynamic shoulder simulator. Each shoulder underwent the following 4 conditions: (1) native, (2) simulated irreparable supraspinatus (SSP) tear, (3) SCR using a nontensioned acellular dermal allograft, and (4) SCR using a graft tensioned with 30 to 35 N. Mean values for maximum glenohumeral abduction and cumulative deltoid forces were recorded. The critical shoulder angle (CSA) was also assessed.

Results:

Native shoulders required a mean (±SE) deltoid force of 193.2 ± 45.1 N to achieve maximum glenohumeral abduction (79.8° ± 5.8°). Compared with native shoulders, abduction decreased after SSP tears by 32% (54.3° ± 13.7°; P = .04), whereas cumulative deltoid forces increased by 23% (252.1 ± 68.3 N; P = .04). The nontensioned SCR showed no significant difference in shoulder abduction (54.1° ± 16.1°) and required deltoid forces (277.8 ± 39.8 N) when compared with the SSP tear state. In contrast, a tensioned graft led to significantly improved shoulder abduction compared with the SSP tear state (P = .04) although abduction and deltoid forces could not be restored to the native state (P = .01). A positive correlation between CSA and maximum abduction was found for the tensioned-graft SCR state (r = 0.685; P = .02).

Conclusion:

SCR using a graft fixed under tension demonstrated a significant increase in maximum shoulder abduction compared with a nontensioned graft; however, abduction remained significantly less than the intact state. The nontensioned SCR showed no significant improvement in glenohumeral kinematics compared with the SSP tear state.

Clinical Relevance:

Because significant improvement in shoulder function after SCR may be expected only when the graft is adequately tensioned, accurate graft measurement and adequate tension of at least 30 N should be considered during the surgical procedure. SCR with a tensioned graft may help maintain sufficient acromiohumeral distance, improve clinical outcomes, and reduce postoperative complications.

Ultrasound Findings Aid Decisions to Repair Partial Articular Supraspinatus Tendon Avulsion

OBJECTIVES

Ultrasound (US) is useful for diagnosing full-thickness rotator cuff tears and high-grade partial-thickness bursal-side tears. However, anisotropy artifacts make it difficult to identify partial articular supraspinatus tendon avulsion (PASTA) by US. This study was performed to determine the diagnostic accuracy of US for PASTA and to uncover sensitive findings that could aid decisions to repair.

METHODS

Patients who underwent preoperative US examinations and supraspinatus tendon confirmation by arthroscopic examinations were enrolled. We analyzed 52 PASTA cases involving greater than 50% thickness of the tendon and 52 age- and sex-matched cases with an intact supraspinatus. Two orthopedic surgeons blinded to the diagnosis interpreted US videos of the supraspinatus tendon. Six findings (echo defect, tendon delamination, echo change, tendon thickness, tendon fiber pattern, and cartilage interface sign) were assessed. We calculated the sensitivity, specificity, and accuracy for each US finding.

RESULTS

The cases consisted of 46 men and 58 women. The US diagnosis of PASTA showed sensitivity of 64.7%, specificity of 94.1%, and accuracy of 79.4%. The echo change in the short axis showed the highest sensitivity. Thinning and delamination showed the highest specificity of 100%. In contrast to previous reports, the sensitivity of the cartilage interface sign was low in both long-axis images (17.6%) and short-axis images (29.4%).

CONCLUSIONS

Preoperative diagnostic US to aid decisions regarding PASTA repair showed high specificity (94.1%) and moderate accuracy (79.4%). However, the sensitivity was only 64.7% and was affected by the examiner's experience with US.