Chronic Pseudoparalysis Needs to Be Distinguished From Pseudoparesis: A Structural and Biomechanical Analysis

The moment arms and lines of action of subscapularis after the Latarjet procedure

The Latarjet procedure is an established surgical treatment for recurrent glenohumeral joint instability with glenoid bone loss. Intraoperatively, the conjoint tendon and its attachement on the coracoid bone graft is routed through a split in subscapularis where the graft is fixed to and augments the anteroinferior glenoid. The objective of this in vitro study was to quantify the influence of glenohumeral joint position and conjoint tendon force on the lines of action and moment arms of subscapularis muscle sub-regions after Latarjet surgery. Eight fresh-frozen, entire upper extremities were mounted onto a testing apparatus, and a cable-pulley system was used to apply physiological muscle loading to the major shoulder muscles. The lines of action and moment arms of four subregions of subscapularis (superior, mid-superior, mid-inferior, and inferior) were quantified radiographically with the conjoint tendon unloaded and loaded while the shoulder was in (i) 0° abduction (ii) 90° abduction (iii) 90° abduction and full external rotation (ABER), and (iv) the apprehension position, defined as ABER with 30° horizontal extension. Conjoint tendon loading after Latarjet surgery significantly increased the inferior inclination of the lines of action of the mid-inferior and inferior subregions of subscapularis in the scapular plane in ABER and apprehension positions (p < 0.001), as well as decreased the horizontal flexion moment arm of the inferior subscapularis (p = 0.040). Increased subscapularis inferior inclination may ultimately increase inferior joint shear potential, while smaller horizontal flexion leverage may reduce joint flexion capacity. The findings have implications for Latarjet surgical planning and postoperative rehabilitation prescription.

Mid- to long-term outcomes of latissimus dorsi tendon transfer for massive irreparable posterosuperior rotator cuff tears: a systematic review and meta-analysis

BACKGROUND

This study aims to analyze the mid-to long-term results of the latissimus dorsi tendon for the treatment of massive posterosuperior irreparable rotator cuff tears as reported in high-quality publications and to determine its efficacy and safety.

METHODS

A systematic review was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. PubMed, Scopus, and EMBASE databases were searched until December 2022 to identify studies with a minimum 4 year follow-up. Clinical and radiographic outcomes, complications, and revision surgery data were collected. The publications included were analyzed quantitatively using the DerSimonian Laird random-effects model to estimate the change in outcomes from the preoperative to the postoperative condition. The proportion of complications and revisions were pooled using the Freeman-Tukey double arcsine transformation.

RESULTS

Of the 618 publications identified through database search, 11 articles were considered eligible. A total of 421 patients (432 shoulders) were included in this analysis. Their mean age was 59.5 ± 4 years. Of these, 277 patients had mid-term follow-up (4-9 years), and 144 had long-term follow-up (more than 9 years). Postoperative improvements were considered significant for the following outcome parameters: Constant-Murley Score (0-100 scale), with a mean difference (MD) = 28 points (95% confidence interval [CI] 21, 36; I2 = 89%; P < .001); visual analog scale, with a standardized MD = 2.5 (95% CI 1.7, 3.3; P < .001; I2 = 89%; P < .001); forward flexion, with a MD = 43° (95% CI 21°, 65°; I2 = 95% P < .001); abduction, with a MD = 38° (95% CI 20°, 56°; I2 = 85%; P < .01), and external rotation, with a MD = 8° (95% CI 1°, 16°; I2 = 87%; P = .005). The overall reported mean complication rate was 13% (95% CI 9%, 19%; I2 = 0%), while the reported mean revision rate was 6% (95% CI: 3%, 9%; I2 = 0%).

CONCLUSIONS

Our pooled estimated results seem to indicate that latissimus dorsi tendon transfer significantly improves patient-reported outcomes, pain relief, range of motion, and strength, with modest rates of complications and revision surgery at mid-to long-term follow-up. In well-selected patients, latissimus dorsi tendon transfer may provide favorable outcomes for irreparable posterosuperior cuff tears.

Rotator cuff tears

Rotator cuff tears are the most common upper extremity condition seen by primary care and orthopaedic surgeons, with a spectrum ranging from tendinopathy to full-thickness tears with arthritic change. Some tears are traumatic, but most rotator cuff problems are degenerative. Not all tears are symptomatic and not all progress, and many patients in whom tears become more extensive do not experience symptom worsening. Hence, a standard algorithm for managing patients is challenging. The pathophysiology of rotator cuff tears is complex and encompasses an interplay between the tendon, bone and muscle. Rotator cuff tears begin as degenerative changes within the tendon, with matrix disorganization and inflammatory changes. Subsequently, tears progress to partial-thickness and then full-thickness tears. Muscle quality, as evidenced by the overall size of the muscle and intramuscular fatty infiltration, also influences symptoms, tear progression and the outcomes of surgery. Treatment depends primarily on symptoms, with non-operative management sufficient for most patients with rotator cuff problems. Modern arthroscopic repair techniques have improved recovery, but outcomes are still limited by a lack of understanding of how to improve tendon to bone healing in many patients.

Pseudoparesis and pseudoparalysis in the setting of massive irreparable rotator cuff tear: demographic, anatomic, and radiographic risk factors

BACKGROUND

The primary purpose of this study was to identify demographic, anatomic, and radiographic risk factors for active forward elevation (AFE) <90° in the setting of massive, irreparable rotator cuff tear (miRCT). The secondary purpose was to identify characteristics differentiating between patients with pseudoparalysis (AFE <45°) and pseudoparesis (AFE >45° but <90°).

METHODS

This was a retrospective case-control study reviewing patients with miRCTs at a single institution between January 12, 2016 and November 26, 2020. Patients were separated into 2 cohorts based on presence or absence of preoperative AFE <90° with maintained passive range of motion. Demographics, RCT pattern, and radiographic parameters were assessed as risk factors for AFE <90°. A secondary analysis was conducted to compare patients with pseudoparalysis and pseudoparesis.

RESULTS

There were 79 patients in the AFE <90° cohort and 50 patients in the control cohort. Univariate analysis confirmed significant differences between the AFE <90° and control cohort in age (71.9 ± 11.0 vs. 65.9 ± 9.1 years), arthritis severity (34.2% vs. 16.0% grade 3 Samilson-Prieto), acromiohumeral distance (AHD; 4.8 ± 2.7 vs. 7.6 ± 2.6 mm), fatty infiltration of the supraspinatus (3.3 ± 0.9 vs. 2.8 ± 0.8) and subscapularis (2.0 ± 1.2 vs. 1.5 ± 1.0), and proportion of subscapularis tears (55.7% vs. 34.0%). On multivariate analysis, age (odds ratio [OR] 1.08, P = .014), decreased AHD (OR 0.67, P < .001), severe arthritis (OR 2.84, P = .041), and subscapularis tear (OR 6.29, P = .015) were independent factors predictive of AFE <90°. Secondary analysis revealed tobacco use (OR 3.54, P = .026) and grade 4 fatty infiltration of the supraspinatus (OR 2.22, P = .015) and subscapularis (OR 3.12, P = .042) as significant predictors for pseudoparalysis compared to pseudoparesis.

CONCLUSIONS

In patients with miRCT, increased age, decreased AHD, severe arthritis, and subscapularis tear are associated with AFE <90°. Furthermore, patients with AFE <90° tend to have greater supraspinatus and subscapularis fatty infiltration. Lastly, among patients with AFE <90°, tobacco use and grade 4 fatty infiltration of the supraspinatus and subscapularis are associated with pseudoparalysis compared with pseudoparesis.

Clinical outcomes and temporal changes in the range of motion following reverse total shoulder arthroplasty

BACKGROUND

Reverse total shoulder arthroplasty is a definitive solution for the treatment of massive rotator cuff tear and shoulder pseudoparalysis since it can improve shoulder function, especially in elderly individuals. For many elderly individuals, the concern is when they can return to their daily lives after surgery. This study aimed to clarify the characteristics of temporal postoperative values following reverse total shoulder arthroplasty and investigate the factors that affect clinical outcomes.

METHODS

This study included 52 patients (mean 79.2 years, range 70-87 years) who underwent primary reverse total shoulder arthroplasty for shoulder pseudoparalysis at a single institution by a single surgeon using the same implant between October 2014 and June 2019. We divided 52 patient into the following groups (1) female (n = 34)vs. male (n = 18) patients; (2) with (n = 19) vs. without (n = 33) arthritic changes in glenohumeral joints (Hamada grade 2, 3 vs. 4, 5); (3) with (n = 23) vs. without (n = 29) subscapularis tendon repair; and investigated the temporal changes in the range of motion (flexion, abduction, external rotation, and internal rotation) and American Shoulder and Elbow Surgeons scores.

RESULTS

Significant differences were observed in postoperative shoulder flexion (P = .046) and abduction (P = .049) between the female and male groups. The male patients were able to obtain quick functional recovery. However, no significant differences were observed in postoperative American Shoulder and Elbow Surgeons scores, and the shoulder range of motion between patients with Hamada grade 2, 3 and 4, 5, and between the subscapularis repair and no repair groups.

CONCLUSION

The factor that affected the final and temporal values of range of motion after reverse total shoulder arthroplasty was sex, rather than the arthritic changes in glenohumeral joint and the treatment of the subscapularis tendon.

Minimal inter-surgeon agreement on the diagnosis of pseudoparalysis in patients with massive rotator cuff tears

BACKGROUND

Pseudoparalysis is commonly used to describe patients with severe loss of active elevation associated with advanced rotator cuff disease, but its definition in the literature has been variable. This study aimed to determine how 15 expert shoulder surgeons use the term "pseudoparalysis" when presented with clinical cases and assess clinical agreement on the diagnosis of pseudoparalysis.

METHODS

Fifteen expert shoulder surgeons were surveyed regarding 18 patients with magnetic resonance imaging-diagnosed massive rotator cuff tears, restricted active range of motion (ROM), full passive ROM, and without advanced rotator cuff arthropathy (Hamada grade <3). The survey included 18 patient vignettes with key clinical details and a deidentified video demonstrating the physical examination of the patient. For all patients, surgeons were instructed to assume that the patient has a full passive ROM. An anteroposterior radiograph and T2 sequences of the patient's coronal, axial, and sagittal magnetic resonance imaging were also provided. After each case, the surgeons were asked: (1) does the patient have pseudoparalysis, and (2) if so, how severe it is. At the end of the patient vignettes, surgeons were asked to define pseudoparalysis using a checklist with predefined options. Surgeons were also asked if there was a difference between the term pseudoparalysis and pseudoparesis. Fleiss' kappa (κ) correlation coefficient was used to determine intersurgeon agreement.

RESULTS

There was minimal inter-rater agreement on the diagnosis of pseudoparalysis (κ = 0.360) and no agreement on describing the severity of pseudoparalysis (κ = -0.057). Although 80% of surgeons stated that an active glenohumeral elevation less than 90° was a diagnostic feature of pseudoparalysis, there was disagreement on the remaining criteria, leading to no agreement on a set of universal criteria that defines pseudoparalysis. A total of 67% included maintained full passive elevation, 33% included the absence of pain, 67% included elevation causing anterosuperior escape, and 27% included an additional unlisted factor. There was minimal agreement among the 15 surgeons on the diagnostic criteria of pseudoparalysis (κ = 0.092). Finally, 7 surgeons stated that pseudoparalysis and pseudoparesis are identical, whereas 8 surgeons stated that they are 2 different clinical diagnoses.

CONCLUSION

Among this panel of expert shoulder surgeons, there was a lack of consensus on the definition of pseudoparalysis and minimal agreement on the diagnosis of pseudoparalysis based on clinical scenarios. In addition, half the surgeons believed that pseudoparalysis and pseudoparesis are identical, whereas the other half believed that they represent 2 separate clinical entities. A standardized definition of pseudoparalysis would be of value to facilitate communication and research efforts.

Effect of Anterior Acromial Coverage on Functional and Radiological Outcomes After Arthroscopic Repair of Anteroposterior Massive Rotator Cuff Tears

BACKGROUND

Rotator cuff tear size, fatty infiltration, and scapular morphology are correlated with tendon healing and functional outcomes after arthroscopic repair; however, the association between anteroposterior acromial coverage and the clinical outcomes of anteroposterior massive rotator cuff tears (AP-MRCTs; involving all 3 tendons) remains unclear.

PURPOSE

To identify the association between AP acromial coverage and functional and radiological outcomes after arthroscopic repair of AP-MRCTs.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

A total of 98 patients who underwent arthroscopic repair of AP-MRCTs between January 2015 and December 2020 were included in the study and classified according to whether anterior acromial coverage (AAC) was anterior (46 patients; positive AAC group) or posterior (52 patients; negative AAC group) to the scapular line on true lateral shoulder radiographs. Demographic characteristics, surgical details, and functional outcomes were prospectively collected. Acromial morphological features, global tear extension (GTE), the global fatty infiltration index (GFII), tendon integrity after repair, proximal humeral migration, and glenohumeral abduction were measured and calculated on radiographs or magnetic resonance imaging scans preoperatively and at 2 years postoperatively. Multivariate logistic regression was performed to identify the independent risk factors of a rotator cuff retear.

RESULTS

The positive AAC group showed larger AAC, posterior acromial tilt, and anterior acromial slope as well as smaller posterior acromial coverage compared with the negative AAC group. Postoperatively, the American Shoulder and Elbow Surgeons score (82.5 ± 8.3 vs 77.2 ± 11.5, respectively; P = .013), active abduction (157.8°± 27.1° vs 142.7°± 39.6°, respectively; P = .048), and glenohumeral abduction (45.6°± 10.4° vs 39.7°± 14.9°, respectively; P = .041) in the positive AAC group were significantly higher than those in the negative AAC group, while the retear rate (23.9% vs 44.2%, respectively; P = .035) and proximal humeral migration (1.7 ± 1.0 vs 2.3 ± 1.2 mm, respectively; P = .006) were significantly lower in the positive AAC group than in the negative AAC group. Smaller AAC (odds ratio [OR], 0.93 [95% CI, 0.87-1.00]; P = .040), larger GTE (OR, 1.03 [95% CI, 1.01-1.06]; P = .017), and a higher GFII (OR, 3.49 [95% CI, 1.09-11.19]; P = .036) were associated with an increased risk of a rotator cuff retear.

CONCLUSION

Increased AAC was associated with a lower retear rate and better functional outcomes after arthroscopic repair of AP-MRCTs. A preliminary risk evaluation integrating GTE, the GFII, and AAC is recommended to consider the necessity of additional procedures for patients in need of arthroscopic rotator cuff repair.

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.

Massive Irreparable Rotator Cuff Tears: Which Patients Will Benefit from Physiotherapy Exercise Programs? A Narrative Review

Massive irreparable rotator cuff tears can cause significant shoulder pain, disability and reduction in quality of life. Treatment approaches can be operative or non-operative. Operative approaches include reverse total shoulder arthroplasty, arthroscopic debridement, partial rotator cuff repair, subacromial balloon spacers, superior capsule reconstruction, and tendon transfer procedures. Non-operative approaches include physiotherapy exercise programs and corticosteroid injections. There are no randomized controlled trials comparing the different treatment approaches. It is therefore challenging for clinicians to advise patients on what is their best treatment pathway. Physiotherapy exercise programs are less expensive and have lower risks for patients than surgical approaches. However, the success of physiotherapy in patients with massive irreparable rotator cuff tears is highly variable with published success rates of 32-96%. Several cohort studies have sought to identify if certain factors are predictive of success with physiotherapy. Several biomechanical factors were identified as possibly being related to a successful or unsuccessful outcome following physiotherapy, with complete tear of subscapularis demonstrating the strongest evidence. However, there were no appropriately designed prognostic studies. There has been a strong emphasis on biomechanical factors. Other domains such as psychosocial factors, which are important in similar patient populations, have not been explored. We recommend that further research is needed in this area and should include randomized controlled trials comparing treatment approaches and longitudinal prospective prognostic studies to identify predictors of treatment success.

The quantification of muscle activities during arm elevation following reverse shoulder arthroplasty or superior capsular reconstruction for irreparable rotator cuff tears using positron emission tomography

BACKGROUND

Reverse shoulder arthroplasty (RSA) and superior capsular reconstruction (SCR) are recognized as surgical options for an irreparable rotator cuff tear. However, the postoperative changes of the muscle activity patterns remain unclear. The purpose of this study was to investigate the quantified muscle activities on shoulder elevation in patients treated with RSA or SCR using fluorine-18-labelled fluorodeoxyglucose-positron emission tomography.

METHODS

Asymptomatic shoulders that underwent RSA or SCR and those without a rotator cuff tear were analyzed as the RSA, SCR, and control groups. All subjects underwent shoulder elevation exercise, followed by a fluorine-18-labelled fluorodeoxyglucose-positron emission tomography examination. Using previously established methods to quantify the uptake of each muscle on positron emission tomography images, the standard uptake values (SUVs) for 16 portions of the deltoid, rotator cuff, and periscapular muscles were obtained to compare the muscle activity patterns among 3 groups.

RESULTS

The deltoid muscle showed the most characteristic differences according to the surgeries. The mean SUVs of the anterior, middle, and posterior deltoid were 3.3, 3.7, and 1.5 for the RSA group; 2.7, 4.2, and 1.5 for the SCR group; and 1.3, 2.0, and 0.9 for the control group, respectively. In comparison to the control group, both the RSA and SCR groups showed significantly increased SUVs at all portions of the deltoid muscle. The RSA group showed similar SUVs for the anterior and middle deltoid, whereas the SCR and control groups showed greatest SUVs at the middle deltoid. In addition, the serratus anterior, levator scapulae, and upper portion of the trapezius in the RSA group showed greater SUVs than in the control group.

CONCLUSION

The deltoid muscle showed increased activity in the RSA and SCR groups. The middle deltoid was mainly used in the SCR group, whereas the anterior and middle deltoid, as well as the upward rotator muscles of the scapula, were mainly used in the RSA group.

Management of Irreparable Posterosuperior Rotator Cuff Tears-A Current Concepts Review and Proposed Treatment Algorithm by the AGA Shoulder Committee

Posterosuperior rotator cuff tears range among the most common causes of shoulder complaints. While non-operative treatment is typically reserved for the elderly patient with low functional demands, surgical treatment is considered the gold standard for active patients. More precisely, an anatomic rotator cuff repair (RCR) is considered the most desirable treatment option and should be generally attempted during surgery. If an anatomic RCR is impossible, the adequate choice of treatment for irreparable rotator cuff tears remains a matter of debate among shoulder surgeons. Following a critical review of the contemporary literature, the authors suggest the following evidence- and experience-based treatment recommendation. In the non-functional, osteoarthritic shoulder, treatment strategies in the management of irreparable posterosuperior RCT include debridement-based procedures and reverse total shoulder arthroplasty as the treatment of choice. Joint-preserving procedures aimed at restoring glenohumeral biomechanics and function should be reserved for the non-osteoarthritic shoulder. Prior to these procedures, however, patients should be counseled about deteriorating results over time. Recent innovations such as the superior capsule reconstruction and the implantation of a subacromial spacer show promising short-term results, yet future studies with long-term follow-up are required to derive stronger recommendations.

Clinical and Functional Outcomes by Graft Type in Superior Capsular Reconstruction: A Systematic Review and Meta-analysis

BACKGROUND

In recent years, superior capsular reconstruction (SCR) has emerged as a promising treatment for massive rotator cuff tears and has been performed with an array of graft options, most commonly dermal allograft and tensor fascia lata (TFL) autograft.

PURPOSE

To compare the clinical outcomes, functional outcomes, and complication rates after SCR performed with dermal allograft, TFL autograft, long head of the biceps tendon (LHBT) autograft, and porcine xenograft.

STUDY DESIGN

Meta-analysis; Level of evidence, 4.

METHODS

PubMed, Cochrane Library, and Embase were systematically reviewed for studies that enrolled ≥10 patients who underwent SCR and presented clinical outcome data at a minimum follow-up of 12 months. When available, pre- and postoperative patient-reported outcome scores and clinical examination data were extracted. Outcome data were then compared by graft type. A meta-analysis was also conducted of graft tear and reoperation rates after SCR with dermal allograft and TFL autograft.

RESULTS

Human dermal allograft and TFL autograft were each utilized in 7 studies, LHBT autograft in 2 studies, and porcine xenograft in 1 study. Dermal allograft, TFL autograft, and LHBT autograft demonstrated comparable median (range) postoperative American Shoulder and Elbow Surgeons scores of 85.3 (77.5-89), 88.6 (73.7-94.3), and 82.7 (80-85.4), respectively. The median postoperative pain scores per visual analog scale for dermal allograft, TFL autograft, and LHBT autograft were 0.8, 2.5, and 1.4. Median postoperative forward elevation was 159.0°, 147.0°, 163.8°, and 151.4° for dermal allograft, TFL autograft, LHBT autograft, and porcine xenograft. Meta-analysis demonstrated a comparable pooled graft tear rate between TFL autograft (9%; 95% CI, 4%-16%) and dermal allograft (7%; 95% CI, 2%-13%). Similarly, the pooled reoperation rate was similar for TFL autograft (3%; 95% CI, 0%-7%) and dermal allograft (6%; 95% CI, 2%-12%). Among the 3 studies with pre- and postoperative information on pseudoparalysis, 73 of 76 (96%) patients with an intact/repairable subscapularis had a reversal of their pseudoparalysis after SCR.

CONCLUSION

Dermal allograft, TFL autograft, and LHBT autograft are all suitable options for SCR and demonstrate significant improvements in American Shoulder and Elbow Surgeons score, pain score per visual analog scale, and forward elevation. Moreover, dermal allograft and TFL autograft have comparable rates of graft tear and reoperation.

Relationship between the progression of posterosuperior rotator cuff tear size and shoulder abduction function: A cadaveric study via dynamic shoulder simulator

Posterosuperior rotator cuff tear (PSRCT) is one of the most common shoulder disorders in elderly people’s daily life; however, the biomechanical relationship between PSRCT and shoulder abduction function is still controversial. In this study, a total of twelve freshly frozen cadaveric shoulders were included and tested in five conditions: intact rotator cuff, 1/3 PSRCT, 2/3 PSRCT, entire PSRCT, and global RCT. In each condition, extra load (0%, 45%, and 90% failure load) was sequentially added to the distal humerus, and the function of the remaining rotator cuff was mainly evaluated via the middle deltoid force (MDF) required for abduction. It is found that the peak MDF is required for abduction did not differ among the three PSRCT conditions (1/3 PSRCT: 29.30 ± 5.03 N, p = 0.96; 2/3 PSRCT: 29.13 ± 9.09 N, p = 0.98; entire PSRCT: 28.85 ± 7.12 N, p = 0.90) and the intact condition (29.18 ± 4.99 N). However, the peak MDF significantly differed between the global RCT (76.27 ± 4.94 N, p < 0.01) and all PSRCT and intact conditions. Under 45% failure load, the MDF of the entire PSRCT and global tear conditions were significantly increased compared with another status. With the 90% failure load, only the 1/3 PSRCT condition maintained the same shoulder function as the intact rotator cuff. These biomechanical testing jointly suggested that the weight-bearing ability of the shoulder significantly decreased as PSRCT progressed.

Rotator cuff tear reaching the superior half portion of the humeral head causes shoulder abduction malfunction

PURPOSE

To examine the biomechanical properties governing posterosuperior rotator cuff (RC) tear progression and dynamic shoulder abduction function, in the absence of excess loading.

METHODS

Twelve freshly frozen cadaveric shoulders were evaluated via an established dynamic shoulder abduction stimulator. The shoulder abduction functions were primarily evaluated using subacromial contact pressure (SACP) during an abduction procedure, and subsequent middle deltoid force (MDF) under 5 conditions: (1) intact, (2) anterior 1/3 posterosuperior rotator cuff (PSRC) tear, (3) anterior 2/3 PSRC tear, (4) entire PSRC tear, and (5) global RC tear (tear involving the entire superior RC).

RESULTS

No obvious differences were observed in the peak MDF required for abduction, and in the peak SACP among the four PSRC tear statuses (49.8 ± 9.2 N, 0.39 ± 0.05 mPa [1/3 PSRC tear]; 49.3 ± 6.8 N, 0.40 ± 0.06 mPa [2/3 PSRC tear]; 51.6 ± 7.0 N, 0.44 ± 0.08 mPa [entire PSRC tear]), as well as intact statuses (48.3 ± 9.8 N, 0.40 ± 0.05 mPa). However, significant elevations in the peak MDF and peak SACP levels were observed among the four PSRC tear statuses and global RC tear (68.1 ± 9.3 N; 4.12 ± 1.50 mPa, P < 0.01).

CONCLUSION

In the absence of excess loading, the biomechanical function of the shoulder was not impaired by a simple PSRC tear. However, once the tear size reached the half superior portion of the humeral head, the humeral head migrated to the surface of the subacromion, and this action markedly decreased shoulder abduction function.

Biomechanical Analysis of Arm Manipulation in Tai Chi

In order to explore the kinematics and muscle force characteristics of competitive Taijiquan arm manipulation, and solve the problems of arm trajectory and control in the process of manipulation, this study puts forward the sports biomechanical analysis of arm manipulation in competitive Taijiquan. The technical characteristics and muscle force characteristics of 15 athletes from the competitive Taijiquan team of Xi'an Institute of physical education were studied. Use Excel 2007 and SPSS17.0 to statistically analyze and process the original data. According to the actual needs, the data indicators are summarized. The combined movements of competitive Taijiquan arm manipulation are captured through high-speed photography, and the kinematic data are statistically analyzed, mainly from the two aspects of action amplitude change and action braking. The results show the action track length, relative track length, and action track length of each plane of the two combined hands. The order of the two combined action tracks is: combination 1 > combination 2, in which the action track in the sagittal plane is the longest in combination 1, and it can also be considered that the motion amplitude in the sagittal plane is the largest in combination 1. The average acceleration of group A in the first beat is 0.51 m/s² smaller than that of group B, and the value is 0.22 m/s² smaller. Therefore, the deceleration of group A is larger than that of group B, and the braking capacity of group A is slightly stronger than that of group B. In the second beat, the average acceleration of group B is 1.5722 m/s² larger than that of group A, and the value is 0.210 m/s² larger. The average acceleration of group A in the third, fourth, fifth, and sixth beats is 0.9, 3.728, 0.57, and 0.837 m/s² smaller than that of group B, and the values are 0.466, 0.174, 0.250, and 0.003 m/s² smaller, indicating that the braking capacity of group A in the third, fourth, fifth, sixth, and eighth beats is slightly stronger than that of group B. In the braking of each beat in combination 1 and combination 2 of group AB, the braking ability of arm manipulation of group A is stronger than that of group B. In competitive Taijiquan, the movement techniques of manipulation include: bouncing technology, braking technology, and control technology. For arm manipulation, athletes should have the ability of "braking" technology. In the correlation analysis of movement track length, RMS and I EMG, the score of athletes in group A is high, and there is no correlation between movement track length and RMS. There is a significant correlation between RMS and movement track length in group B, and the correlation degree is moderate. This shows that when the movement of group B athletes is completed, the muscles are in a state of tension, the movement skills are not mastered well, and the energy saving is not achieved. During training, we should pay more attention to the proprioception of muscles and form a correct way of muscle exertion.

Behandlung, Verlauf und Therapieerfolg der Neuropathie des Nervus tibialis bei Deutsch-Holstein Kühen

Gegenstand und Ziel Nach bereits publizierten Ergebnissen dieser prospektiven Studie zu Vorkommen, Vorbericht, klinischem Bild der Neuropathie des N. tibialis (Tibialis-Neuropathie, TN) war es Ziel auf Behandlung und Prognose dieser Erkrankung einzugehen.

Material und Methoden Von 88 Deutsch-Holstein-Kühen mit ein- (ETN, n = 71) und beidseitiger (BTN, n = 17) TN konnten Daten von 68 Kühen (56 ETN, 12 BTN) ausgewertet werden. Sie wurden retrospektiv 4 Gruppen zugeteilt: ohne Behandlung – spontane Ausheilung innerhalb 48 h (Spontan, 5 ETN), kein Verband (0Cast, 8 ETN, 3 BTN) bzw. mit Behandlung mit Antiphlogistika und Stützverband (StV, 3 ETN) oder Kunstharzverband (Cast, 40 ETN, 9 BTN). Zu 5 Zeitpunkten (14, 21, 28, 42, 56 d nach Erstvorstellung) erfolgten Kontrollen der behandelten Kühe. Zur letzten Kontrolle erfolgte bei 29 Kühen, wie bereits zur Erstvorstellung, eine Bestimmung der Plasma-Kreatinkinase-Aktivität.

Ergebnisse Bei behandelten Kühen mit ETN wurde eine deutlich höhere Ausheilungsrate beobachtet als bei unbehandelten Kühen (Cast 98 % und StV 100 % vs. 0Cast 62 %). Im Vergleich dazu war der beobachtete Unterschied zwischen behandelten und unbehandelten Kühen mit BTN nicht so deutlich (78 % vs. 67 %). Die ermittelte Überlebensdauer der Kühe nach Ausheilung der TN war höher als ohne Ausheilung (545 d vs. 100 d). Die initial erhöhten Plasma-Kreatinkinase-Aktivitäten näherten sich nach Behandlung wieder dem Referenzbereich (434 U/l vs. 152 U/l).

Schlussfolgerungen Insbesondere für die ETN ist nach Therapie mit Antiphlogistika und stabilisierendem Verband die Prognose als sehr gut anzusehen. Bei BTN war die Prognose abhängig von Art und Grad der Primärschädigung. Hinweise für eine schlechte Prognose waren insbesondere Ausfälle der Hautsensibilität. Bei guter Prognose ist die Therapie der TN aus wirtschaftlicher Sicht zu empfehlen, da in dieser Studie die Kühe nach Ausheilung im Mittel bis mindestens zur darauffolgenden Laktation gehalten werden konnten.

Klinische Relevanz Die Studie verdeutlicht die Vorteile der Behandlung mit einem stabilisierenden Verband im Ausheilungsverlauf der TN. Bei der TN scheint im Vergleich zu Neuropathien anderer peripherer Nerven die Schädigung der Muskulatur von besonderer Bedeutung für das Krankheitsgeschehen zu sein.

Pseudoparalysis and Acromiohumeral Interval Reversibility Are the Most Important Factors Affecting the Achievement of Patient-Acceptable Symptom State After Arthroscopic-Assisted Latissimus Dorsi Tendon Transfer

PURPOSE

To determine the patient-acceptable symptom state (PASS) values for American Shoulder and Elbow Surgeons (ASES) score and the Constant-Murley (CM) score after arthroscopic-assisted latissimus dorsi tendon transfer (LDTT) and to identify potential factors affecting the achievement of PASS.

METHODS

Fifty consecutive patients who underwent arthroscopic-assisted LDTT between 2015 and 2020 were retrospectively analyzed. In total, 42 patients met the inclusion criteria with minimum follow-up of 1 year postoperative. Patients were evaluated preoperatively and 1-year postoperatively with multiple clinical measurements including ASES, CM, score and PASS. The primary outcome was identified as patient satisfaction which assessed with achievement of a PASS. Potential factors affecting the patient satisfaction including age, sex, body mass index, previous surgery, presence of pseudoparalysis, critical shoulder angle, shoulder abduction moment index, acromiohumeral interval (AHI) reversibility, Hamada grade and fatty infiltration were evaluated for their association with PASS value by stepwise logistic regression analysis.

RESULTS

A total of 42 patients were evaluated with mean follow-up 27.8 ± 8.21 months. The ASES and CM scores improved from preoperative means of 21.6 ± 6.5 and 25.2 ± 8.5 to 65.6 ± 20.7 points and 56.8 ± 16.5 points, respectively (P < .001). The PASS values for the ASES and CM scores were 62.4 and 52.5, respectively. The univariate analysis showed that older age (P = .021), presence of pseudoparalysis (P < .001), previous surgery (P = .016), lower preoperative AHI (P = .028), and lower AHI reversibility (P < .001) were all significantly associated with worse patient satisfaction. The multivariable logistic regression analysis showed that pseudoparalysis (P = .038) and AHI reversibility (P = .021) were independent prognostic factors affecting the achievement of a PASS after arthroscopic-assisted LDTT. The cutoff value for AHI reversibility to predict an achievement of PASS was found to be 4.0 mm.

CONCLUSIONS

Arthroscopic-assisted LDTT led to satisfactory results in patients with massive rotator cuff tears. However, pseudoparalysis and AHI reversibility were the most important independent prognostic factors that consistently reduced and increased, respectively, the odds of achieving a PASS.

LEVEL OF EVIDENCE

Level IV, retrospective case series.

Effect of Active and Passive Function of the Posterosuperior Rotator Cuff on Compensatory Muscle Loads in the Shoulder

Background:

Irreparable posterosuperior rotator cuff (PSRC) tears have been shown to result in shoulder pain and loss of function.

Purpose/Hypothesis:

The purpose of this study was to determine the effect of the loss of active or passive function of the PSRC on compensatory muscle loads in the deltoid and the remaining rotator cuff. It was hypothesized that both deactivation and resection of the PSRC would result in load increases in the remaining muscles and that resection of the PSRC would result in even higher required compensatory forces than would mere deactivation.

Study Design:

Controlled laboratory study.

Methods:

A total of 7 cadaveric shoulders were tested using a biomechanical shoulder simulator with 10 independently controlled actuators for various muscles (anterior, middle, and posterior deltoid; inferior and superior subscapularis; latissimus dorsi; pectoralis major; teres minor; supraspinatus; and infraspinatus) and 3-dimensional motion tracking. The muscle loads representing the latissimus dorsi and pectoralis major were each held constant, and the remaining muscle actuator forces required to abduct the arm in the scapular plane were determined. The actuator forces corresponding with arm elevation from 20° to 65° were compared at 5° increments for 3 testing conditions: (1) intact, active PSRC; (2) intact, deactivated PSRC; and (3) resected PSRC and shoulder capsule.

Results:

In both the deactivated and resected states, the teres minor showed a significant increase in required muscle forces through nearly the entire tested range of arm elevation compared to the active state. This was also the case for the subscapularis but only at higher elevation angles. The deltoid demonstrated increased muscle forces of at least 1 of its subunits between 25° and 55° of elevation when comparing the deactivated state or resected state to the active state. However, through nearly the entire range of elevation, no statistically significant differences were found between the deactivated and resected states for any of the actuator loads representing muscle forces.

Conclusion:

The loss of active function of the PSRC led to compensatory loads on the remaining rotator cuff and deltoid, regardless of the passive presence of the PSRC as a supposed subacromial spacer.

Clinical Relevance:

The findings encourage the exploration of treatment procedures that mimic the active function of the PSRC when the rotator cuff itself is irreparable.

Primary Open Latarjet Procedure Results in Functional Differences but No Structural Changes in Subscapularis Muscle Quality vs the Healthy Contralateral Shoulder at Long-term Follow-up

BACKGROUND

There are concerns that the Latarjet procedure results in loss of glenohumeral rotation and strength and in subscapularis dysfunction. The long-term effects of this procedure on subscapularis quality, glenohumeral rotation, and strength are unknown.

PURPOSE/HYPOTHESIS

To analyze the long-term effect of the primary open Latarjet procedure using a muscle-splitting approach on internal and external rotation and strength, as well as subscapularis muscle quality as compared with the healthy contralateral side. We hypothesized that the primary open Latarjet procedure is associated with a reduction of long-term shoulder strength and function and decreased subscapularis quality.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

A total of 42 patients who underwent a primary open Latarjet procedure for recurrent anterior shoulder instability at a mean age of 26 years (range, 18-36) were reviewed after a mean follow-up of 8.4 years (range, 5-12). The subscapularis muscle volume and fat fraction of both shoulders were assessed. Bilateral active internal rotation (IR) and external rotation (ER), as well as IR and ER strength, were assessed by isokinetic testing (concentric, eccentric, and fatigability).

RESULTS

Active IR (0.6-point difference, P < .001) and ER (4° difference, P = .010) were significantly greater in healthy contralateral shoulders. The IR strength of the operated shoulder was significantly less than that of the healthy shoulder in concentric and eccentric testing (range of deficit, 4%-6%; P < .05). Also, the ER strength of the operated shoulder was significantly less than that of the healthy shoulder in concentric testing (11% deficit, P < .05). Subscapularis muscle volume was significantly greater in the operated shoulder (4% difference, P = .022), and there was no significant difference in fat fraction (P = .114).

CONCLUSIONS

The primary open Latarjet procedure was associated with significantly decreased active IR and ER and strength when compared with the healthy contralateral shoulder. The clinical influence of these findings is yet to be defined. There was no increased subscapularis muscle fatty degeneration but a minimal hypertrophy on the operated side at long-term follow-up.

Medialized vs. lateralized humeral implant in reverse total shoulder arthroplasty: the comparison of outcomes in pseudoparalysis with massive rotator cuff tear

BACKGROUND

With the increasing use of lateralized humeral implants in reverse total shoulder arthroplasty (RTSA), it is still unclear whether this design will be as advantageous as the medialized humeral implants in the setting of pseudoparalysis (PP).

METHODS

A total of 51 eligible RTSA cases for PP signs due to massive rotator cuff deficiency were selected for the retrospective review. Twenty-five patients were allocated to group L in which the isolated humeral side lateralization was performed (neck-shaft angle of 145°), and 26 patients were allocated to group M (neck-shaft angle of 155°). Pre- and postoperative radiologic measurements including critical shoulder angle, acromiohumeral distance (AHD), lateral humeral offset (LHO), and deltoid wrapping offset (DWO), as well as range of motion (ROM) and clinical outcome scores, were compared. The mean age was 71.0 ± 6.5 years for group L and 70.3 ± 7.0 years for group M, and the overall mean follow-up period was 49.0 ± 13.5 months (range, 25.7-68.9).

RESULTS

The preoperative radiologic measurements were similar, but the postoperative LHO and DWO were significantly larger for group L, whereas the postoperative AHD was larger for group M compared with group L, with the values being 39.8 ± 9.7 mm and 33.6 ± 10.4 mm, respectively (P = .034). For the ROM, active forward elevation did improve significantly for both, starting preoperatively with the active ranges of 39° ± 19° (passively 153° ± 24°) for group L and 42° ± 18° (passively 156° ± 11°) for group M-the final postoperative active ranges being 142° ± 16° and 133° ± 33°, respectively, without significant difference between the groups (P = .426). The postoperative recovery of PP for group L was 100% (25 of 25), whereas for group M, it was 96.2% (25 of 26). The final visual analog scale (VAS) scores and University of California Los Angeles (UCLA) shoulder scores improved significantly for both groups, but the differences between the groups at the final assessments were insignificant. The 4 complications were periprosthetic fracture, acromial stress fracture, periprosthetic joint infection, and neuropraxia, all of which were in group M, and scapular notching with higher grades were more prevalent for group M (26.9%, 7 of 26).

CONCLUSIONS

With RTSA, good outcomes and recovery were achieved in most cases of PP. The postoperative active elevation range and functional outcomes were not affected by medialization or lateralization of the humeral implant. Earlier recovery of motion was observed with the lateralized group, but no significant differences were seen in the final ROM between the groups.

Management of the failed rotator cuff repair

Rotator cuff repair is increasingly being performed, and this is likely to continue to given the ageing population. An improvement in functional outcome can be achieved, with the best results noted in those tendons that go on to heal. Failure of repair following surgery can be associated with debilitating symptoms that are not always amenable to non-operative measures, so further surgery may be indicated for these patients. Several operative strategies have been described, but careful evaluation is required to determine the most suitable option. This review describes the decision-making strategies and treatment options available during management of a failed rotator cuff repair.

Graft-Augmented Repair of Irreparable Massive Rotator Cuff Tears with Latissimus Dorsi Transfer to Treat Pseudoparesis

Irreparable massive rotator cuff tears are characterized by a poor prognosis with high failure rates following repair. Numerous strategies, such as partial repair, graft interposition, latissimus dorsi (LD) transfer, balloon arthroplasty, and superior capsular reconstruction, have been proposed. We have adopted a graft-augmented LD-transfer procedure, in which partial repair, graft interposition, and LD transfer are performed simultaneously.

Posterior Open-wedge Osteotomy and Glenoid Concavity Reconstruction Using an Implant-free, J-shaped Iliac Crest Bone Graft in Atraumatic Posterior Instability with Pathologic Glenoid Retroversion and Dysplasia: A Preliminary Report

BACKGROUND

Atraumatic posterior shoulder instability in patients with pathologic glenoid retroversion and dysplasia is an unsolved problem in shoulder surgery.

QUESTIONS/PURPOSES

In a preliminary study of a small group of patients with atraumatic posterior shoulder instability associated with glenoid retroversion ≥ 15° and glenoid dysplasia who underwent posterior open-wedge osteotomy and glenoid concavity reconstruction using an implant-free, J-shaped iliac crest bone graft, we asked: (1) What proportion of the patients had persistent apprehension? (2) What were the improvements in patient-reported shoulder scores? (3) What were the radiographic findings at short-term follow-up?

METHODS

Between 2016 and 2018, we treated seven patients for atraumatic posterior shoulder instability. We performed this intervention when posterior shoulder instability symptoms were unresponsive to physiotherapy for at least 6 months and when it was associated with glenoid retroversion ≥ 15° and dysplasia of the posteroinferior glenoid. All seven patients had a follow-up examination at a minimum of 2 years. The median (range) age at surgery was 27 years (16 to 45) and the median follow-up was 2.3 years (2 to 3). Apprehension was assessed by a positive posterior apprehension and/or posterior jerk test. Patient-reported shoulder scores were obtained and included the subjective shoulder value, obtained by chart review (and scored with 100% representing a normal shoulder; minimum clinically important difference [MCID] 12%), and the Constant pain scale score (with 15 points representing no pain; MCID 1.5 points). Radiographic measurements included glenohumeral arthropathy and posterior humeral head subluxation, bone graft union, correction of glenoid retroversion and glenoid concavity depth, as well as augmentation of glenoid surface area. All endpoints were assessed by individuals not involved in patient care.

RESULTS

In four of seven patients, posterior apprehension was positive, but none reported resubluxation. The preoperative subjective shoulder value (median [range] 40% [30% to 80%]) and Constant pain scale score (median 7 points [3 to 13]) were improved at latest follow-up (median subjective shoulder value 90% [70% to 100%]; p = 0.02; median Constant pain scale score 15 points [10 to 15]; p = 0.03). Posterior glenoid cartilage erosion was present in four patients (all four had Walch Type B1 glenoids) preoperatively and showed no progression until the final follow-up examination. The median (range) humeral head subluxation index decreased from 69% (54% to 85%) preoperatively to 55% (46% to 67%) postoperatively (p = 0.02), and in two of four patients with preoperative humeral head subluxation (> 65% subluxation), it was reversed to a centered humeral head. CT images showed union in all implant-free, J-shaped iliac crest bone grafts. The median preoperative retroversion was corrected from 16° (15° to 25°) to 0° postoperatively (-5° to 6°; p = 0.02), the median glenoid concavity depth was reconstructed from 0.3 mm (-0.7 to 1.6) preoperatively to 1.2 mm (1.1 to 3.1) postoperatively (p = 0.02), and the median preoperative glenoid surface area was increased by 20% (p = 0.02). No intraoperative or postoperative complications were recorded, and no reoperation was performed or is planned.

CONCLUSION

In this small, retrospective series of patients treated by experienced shoulder surgeons, a posterior J-bone graft procedure was able to reconstruct posterior glenoid morphology, correct glenoid retroversion, and improve posterior shoulder instability associated with pathologic glenoid retroversion and dysplasia, although four of seven patients had persistent posterior apprehension. Although no patients in this small series experienced complications, the size and complexity of this procedure make it likely that as more patients have it, some will develop complications; future studies will need to characterize the frequency and severity of those complications, and we recommend that this procedure be done only by experienced shoulder surgeons. The early results in these seven patients justify further study of this procedure for the proposed indication, but longer term follow-up is necessary to continue to assess whether it is advantageous to combine the reconstruction of posterior glenoid concavity with correction of pathological glenoid retroversion and increasing glenoid surface compared with traditional surgical techniques such as the posterior opening wedge osteotomy or simple posterior bone block procedures.

LEVEL OF EVIDENCE

Level IV, therapeutic study.

Anatomical study of the teres major muscle: description of an additional distal muscle slip

Background

Understanding muscle and tendon anatomy is of tremendous importance to achieve optimal surgical execution and results in tendon transfers around the shoulder. The aim of this study was to introduce and describe an additional distal muscle slip of the teres major (TM).

Methods

Sixteen fresh-frozen cadaver shoulders were dissected with the deltopectoral approach. The ventral latissimus dorsi (LD) tendon was harvested, and the shoulders were analyzed for the presence/absence of a distal teres major slip (dTMs) and its dimensions and relationship with the TM and LD tendons.

Results

The dTMs was identified in 12 shoulders (75%). It was always distal to the TM tendon and visible during the deltopectoral approach. There was a clear separation between the TM proximally and dTMs tendon distally. At the humeral insertion, both tendons had a common epimyseal sheet around the teres major and inserted continuously at the humerus. The mean width of the dTMs tendon at the insertion was 13 ± 4 mm (range, 7–22 mm). The total lengths of the dTMs tendon and LD tendon were 40 ± 7 mm (range, 25–57 mm) and 69 ± 7 mm (range, 57–79 mm), respectively (p < 0.001). The dTMs muscle showed direct adhesions in ten shoulders (83%) with the LD muscle.

Conclusions

This is the first macroscopic description of an additional distal slip of the teres major muscle. The dTMs has a separate (distal) but continuous (mediolateral) insertion at the humerus within a common epimyseal sheet around the TM. The dTMs tendon is visible during the deltopectoral approach and can therefore provide a lead structure, particularly in ventral LD transfers with the deltopectoral approach.