Unravelling a Triad: A Rare Case of Takayasu Arteritis, Hashimoto's Thyroiditis, and Psoriasis in a Young Female With Heart Failure.

Takayasu arteritis (TA) is an autoimmune entity of unknown aetiology causing granulomatous thickening of large and medium-sized arteries. Common symptoms include claudication, headaches, dizziness, syncope, visual changes, and palpitations. Diverse cardiac manifestations, such as ischemic heart disease, significant aortic regurgitation, and pulmonary hypertension, are associated with TA, although they rarely manifest as congestive heart failure. Radio-imaging, including CT angiography and MR angiography, along with more invasive procedures such as conventional angiography, are often used for diagnosis. Treatment is done with corticosteroids, steroid-sparing agents, biologics, and revascularization procedures. Here, we have a case of a 17-year-old Indian female who presented to us with a complaint of abdominal pain. She was diagnosed with Hashimoto's thyroiditis a few years ago, along with a history of congestive heart failure. On general examination, blood pressure was asymmetrical in the upper limbs with the presence of bilateral carotid bruit. There was also the presence of extensive scaly lesions on the extensor surface of all four limbs, suggestive of psoriasis. Radio-imaging confirmed the diagnosis of TA. CT angiography also showed total occlusion of the celiac trunk and proximal left gastric artery, which was likely the cause of her symptoms. The patient received treatment with corticosteroids in conjunction with methotrexate, along with other supportive drugs. TA with congestive heart failure has been occasionally described in the literature, while the association of TA with psoriasis is much rarer. The simultaneous occurrence of various autoimmune diseases is common, but the triad of Hashimoto thyroiditis, psoriasis, and TA with an initial presentation of heart failure is unique. Due to the common co-occurrence of autoimmune conditions, early and thorough patient evaluation with comprehensive studies is imperative for optimal health outcomes.

Lead Extraction and Baffle Stenting in a Patient with Transposition of the Great Arteries.

This case report discusses a 42-year-old male with dextro-transposition of the great arteries (D-TGA) status post Mustard repair and sick sinus syndrome status post dual-chamber pacemaker implant, who developed symptomatic superior vena cava (SVC) baffle stenosis. He was treated with a combined pacemaker extraction and subsequent SVC baffle stenting. The case highlights the complexities of treating SVC baffle stenosis in the presence of cardiac implantable devices and demonstrates the efficacy of this combined approach. Furthermore, the authors delve into the intricacies of D-TGA, its surgical history, and the long-term complications associated with atrial switch procedures.

Ten Pearls for Anterior Cruciate Ligament Reconstruction.

Anterior cruciate ligament (ACL) reconstruction is a common orthopaedic procedure that has continued to evolve. Since it is a complex procedure, it carries a risk of a range of complications. To ensure optimal results, there are many important considerations to take such as the choice of graft, tunnel positioning, graft preparation, and many others. In this technical note, we elucidate our top 10 pearls to consider for a successful ACL reconstruction.

Biomechanical Characterization of a New Locking Loop Stitch for Graft Fixation versus Krackow Stitch.

Background: The purpose of this study was to quantify and compare the biomechanical characteristics of a new locking loop stitch (LLS), developed utilizing the concepts of both running locking stitch and needleless stitch, to the traditional Krackow stitch. Methods: The Krackow stitch with No.2 braided suture and the LLS with 1.3-mm augmented polyblend suture tape were compared biomechanically. The LLS was performed with single strand locking loops and wrapping suture around the tendon, resulting in half the needle penetrations through the graft compared to the Krackow stitch. Twenty bovine extensor tendons were divided randomly into two groups. The tendons were prepared to match equal thickness and cross-sectional area. Each suture-tendon was stitched and preloaded to 5 N for 60 seconds, cyclically loaded to 20 N, 40 N, and 60 N for 10 cycles each, and then loaded to failure. The deformation of the suture-tendon construct, stiffness, yield load, and ultimate load were measured. Results: The LLS had significantly less deformation of the suture-tendon construct at 100 N, 200 N, 300 N, and at ultimate load compared to the Krackow stitch (Krackow stitch and LLS at 100 N: 1.3 ± 0.1 mm and 1.0 ± 0.2 mm, p < 0.001; 200 N: 3.0 ± 0.3 mm and 1.9 ± 0.2 mm, p < 0.001; 300 N: 5.1 ± 0.6 mm and 2.9 ± 0.4 mm, p < 0.001; ultimate load: 12.8 ± 2.8 mm and 5.0 ± 1.2 mm, p < 0.001). The LLS had significantly greater stiffness (Krackow stitch and LLS: 97.5 ± 6.9 N/mm and 117.2 ± 13.9 N/mm, p < 0.001) and yield load (Krackow stitch and LLS: 66.2 ± 15.9 N and 237.9 ± 93.6 N, p < 0.001) compared to the Krackow stitch. There was no significant difference in ultimate load (Krackow stitch: 450.2 ± 49.4 N; LLS: 472.6 ± 59.8 N; p = 0.290). Conclusions: The LLS had significantly smaller deformation of the suture-tendon construct compared to the Krackow stitch. The LLS may be a viable surgical alternative to the Krackow stitch for graft fixation when secure fixation is necessary.

Obesity associated with improved mortality of extracorporeal membrane oxygenation for severe COVID-19 pneumonia.

INTRODUCTION: Determining a patient's candidacy for extracorporeal membrane oxygenation (ECMO) in severe COVID-19 pneumonia is a critical aspect of efficient healthcare delivery. A body mass index (BMI) ≥40 is considered a relative contraindication for ECMO by the Extracorporeal Life Support Organization (ELSO). We sought to determine the impact of obesity on the survival of patients with COVID-19 on ECMO. METHODS: This project was a retrospective review of a multicenter US database from January 2020 to December 2021. The primary outcome was in-hospital mortality after ECMO initiation, with a comparison between patients classified into body mass index categories (<30, 30-39.9, and ≥40). Secondary outcomes included ventilator days, intensive care days, and complications. RESULTS: We completed records review on 359 patients, with 90 patients excluded because of missing data. The overall mortality for the 269 patients was 37.5%. Patients with a BMI <30 had higher odds of mortality compared to all patients with BMI >30 (OR 1.98; p = 0.013), those with BMI 30-39.9 (OR 1.84; p = 0.036), and BMI ≥40 (OR 2.33; p = 0.024). There were no differences between BMI groups for ECMO duration; length of stay (LOS); or rate of bloodstream infection, stroke, or blood transfusion. Age, ECMO duration, and modified-Elixhauser index were not independent risk factors for mortality. CONCLUSIONS: In patients receiving ECMO for severe COVID-19, neither obesity (BMI >30) nor morbid obesity (BMI >40) were associated with in-hospital mortality. These results are consistent with previous reports and held true after adjusting for age and comorbidities. Our data suggest further examination of the recommendations to withhold ECMO in patients who are obese.

Can We Identify Why Athletes Fail to Return to Sports After Arthroscopic Bankart Repair? A Systematic Review and Meta-analysis.

BACKGROUND: No previous systematic reviews have reported on athletes who fail to return to sports after arthroscopic Bankart repair. PURPOSE: To review the literature on athletes who fail to return to sports after arthroscopic Bankart repair to determine the rate of athletes who did not return to sports and to identify the specific reasons for failure to return to sports by nonreturning athletes. STUDY DESIGN: Systematic review and meta-analysis. METHODS: A meta-analysis was conducted following the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. Three electronic databases (PubMed, Scopus, Web of Science) were queried for articles meeting the inclusion criteria. Studies were considered eligible only if reporting the rate of failure for return to sports and providing the specific reasons why athletes were unable to return to sports. All records were screened by title, abstract, and full text by 2 authors independently, with any discrepancies resolved by a third senior author. For articles selected for inclusion, data were collected on the number of athletes, average age, average follow-up time, type of sport played, rate of failure to return to sports, and specific reasons for failure to return. A random-effects model was used to conduct the meta-analysis. RESULTS: Seventeen studies were selected for inclusion reporting on a total of 813 athletes. The calculated weighted rate of failure to return to sports after arthroscopic Bankart repair was 15.6% (95% CI, 10.9%-21.1%). A significantly higher proportion of athletes cited shoulder-dependent versus shoulder-independent reasons for failure to return to sports (81.7% vs 18.3%; P < .0001). The most cited reasons for failure to return included recurrent or persistent instability (33.3%), fear of reinjury (17.7%), apprehension (9.9%), changes in priorities or personal interest (8.5%), lack of time (7.1%), and discomfort or pain with sports (6.4%). CONCLUSION: Our study estimated the rate of failure to return to sports after arthroscopic Bankart repair to be 15.6%, with most athletes citing shoulder-related reasons as the primary factor precluding return. Identifying the potential reasons preventing successful return to sports can guide surgeons in counseling athletes regarding postoperative expectations and addressing hesitations for returning to sports.

Idiopathic Retroperitoneal Fibrosis Presented As Urinary Tract Obstruction.

Retroperitoneal fibrosis (RPF) or Ormond's disease is a very uncommon fibro-inflammatory disease, under the umbrella of systemic autoimmune diseases. The majority of cases are idiopathic, known as idiopathic RPF (IRPF); however, diseases secondary to other causes are also seen in clinical practice. The commonest presenting features are seen due to the effects of fibrous tissue around iliac vessels, aorta and ureters, where compression of ureters is the major and most common complication. Computed tomography (CT) scans and magnetic resonance imaging (MRI) are the modalities of choice for the diagnosis. The primary management involves medical therapy with corticosteroids and reserving surgical options for ureteric obstruction and related complications. We present a case of a 65-year-old man who presented with bilateral pedal oedema, facial puffiness, decreased appetite, decreased urine output, and breathlessness with dry cough, tachypnoea, hypoxia and crepitation in both lung fields on examination. The blood investigations were suggestive of acute kidney injury (AKI); whereas radio imaging diagnosed him as a case of bilateral hydroureteronephrosis with RPF. The patient was treated for AKI in the case of IRPF. Once the patient stabilized, a low-dose systemic steroid was started for IRPF, and subsequently, the patient underwent stent placement surgery for ureteric obstruction. RPF, being a rare disease, is difficult to diagnose. However, CT and MRI scanning can easily reveal fibrous tissue surrounding the aorta and ureters. Medical management with glucocorticoids is the backbone drug for the disease, keeping surgery as a reserved option for ureteric obstruction and its complications.

Emphysematous Cystitis: A Fatal Complication of Uncontrolled Type-2 Diabetes Mellitus.

Emphysematous cystitis (EC) is a rare type of complicated urinary tract infection mostly seen in elderly females with diabetes, characterized by gas within the bladder lumen and wall. The presenting symptoms are variable, ranging from no symptoms to severe sepsis. The commonly isolated organisms in urine cultures are Escherichia coli and Klebsiella pneumoniae. Imaging studies, namely plain conventional abdominal radiography and computed tomography, are necessary to make a definitive diagnosis of EC. The management includes medical treatment with culture-guided antibiotics, whereas surgical intervention such as cystectomy is rarely required in severe cases. Here, we have a case of a 48-year-old diabetic female diagnosed with EC on radio imaging. The patient was aggressively treated with higher antibiotics such as piperacillin/tazobactam, clindamycin, and fosfomycin along with measures to control blood sugars. However, she developed severe sepsis and succumbed to death. Our report presents one of the rare cases of EC as a life-threatening complication in diabetics, suggesting that every case of urinary tract infection in uncontrolled diabetics should be thoroughly investigated and treated to prevent fatal complications.

A Rare Phenotype of Inherited Cerebellar Ataxia.

Ataxia is a syndrome of imbalance and incoordination, categorized as hereditary ataxias, degenerative ataxias (non-hereditary), and acquired ataxias. Hereditary ataxia is further classified based on its mode of inheritance. Here, we have reported a case of early-onset autosomal recessive cerebellar ataxia with retained reflexes in a young male with positive family history. A young male presented with ten years history of tremors in both hands and head, aggravated with work and relieved with rest, and imbalance while walking, which has now progressed to the level where the patient cannot walk without support. The patient's younger brother also had a similar history. Central nervous system examination revealed cerebellar ataxia with retained reflexes. After ruling out other causes of ataxia in this age group by investigations, we could make the diagnosis of early-onset cerebellar ataxia with retained tendon reflexes (autosomal recessive). Presenting as a disease of variable presentation, the important diagnostic cues are classification and localization of ataxia. The investigations should be focusing on those cases of ataxias that are treatable. Family history is important to identify hereditary ataxias, as well as in genetic counselling of the affected patients.

Mucormycosis, Diabetes and COVID-19 Pneumonia: Unleashing the Facts.

Background Mucormycosis (MM) is an angioinvasive locally destructive fungal infection. Before the coronavirus disease 2019 (COVID-19) pandemic, it was associated with diabetes (particularly diabetic ketoacidosis), immunosuppressive drugs and trauma. Among its various forms, cerebral invasion is considered to be highly fatal even if with long-term treatment. Treatment with injection amphotericin B (Amph-B) with early surgical interventions is highly efficacious. Liposomal preparation is considered to be superior in the context of fewer side effects. Methods We present a single-centre prospective study of 124 patients with MM in a tertiary care hospital. After the approval from the ethics committee, basic information was taken from all patients including all available past history about the COVID-19 infection and treatment. The studied outcomes were discharge, death and number of days of hospitalisation. Secondary objectives were to estimate the association of MM with known risk factors, to find the association of an outcome with various inflammatory markers, to determine adverse events with the use of injection Amph-B and posaconazole and to find the case fatality rate of MM. Results In our study, we observed that the number of patients with MM was double in the less than 60 years age group. However, mortality was 33.3% in the elderly as compared to 15.29% in patients less than 60 years of age. The majority of the patients (69.35%) were males, but no significant difference in mortality was seen between males and females. The case fatality rate was 20.97%. Ocular symptoms such as orbital swelling and pain were the common presenting symptoms. Almost all patients (93.54%) were diabetics. The non-diabetic group consisted of only 8 (6.4%) patients, and therefore, the comparison was not possible. A total of 20 (16%) out of 124 patients who had received high-dose steroids showed higher mortality (55%). Maximum patients (65.32%) had presented with MM following a past COVID-19 infection. However, a significant number of MM patients (20.96%) had a recent COVID infection and had higher mortality (57.69%) compared to their counterparts. The most common site of involvement in our study was the paranasal sinus (50%) and the outcome was the best in those patients whose disease was localised only to the sinuses, although among 14 (11.29%) patients with cerebral involvement, mortality was maximum (42.85%). Renal impairment and dyselectrolytemia were the most common adverse effects of Amph-B, and 46.42% of patients required surgical removal of the local part. Conclusion We saw that diabetes was a major contributory factor in the etiopathogenesis of MM. COVID-19 could also be a major causative factor by impairing the immune system; however, further studies at the molecular level are required to establish an association. The use of steroid cannot be the only independent risk factor, and other associated factors must be present. Treatment with antifungal and early surgical intervention had good outcomes. Treatment with conventional lyophilized Amph-B was equally efficacious as lipid-based solutions, but with more side effects. Hypokalemia and hypocalcemia were the most common electrolyte abnormalities associated with the use of injection Amph-B. Uncontrolled diabetes, the severity of the COVID-19 infection at presentation, acidosis, a high C-reactive protein level (above 100) and local brain involvement were associated with a poor outcome.

Biomechanical investigation of arm position on deforming muscular forces in proximal humerus fractures.

BACKGROUND: Muscular forces drive proximal humeral fracture deformity, yet it is unknown if arm position can help mitigate such forces. Our hypothesis was that glenohumeral abduction and humeral internal rotation decrease the pull of the supraspinatus and subscapularis muscles, minimizing varus fracture deformity. METHODS: A medial wedge osteotomy was performed in eight cadaveric shoulders to simulate a two-part fracture. The specimens were tested on a custom shoulder testing system. Humeral head varus was measured following physiologic muscle loading at neutral and 20° humeral internal rotation at both 0° and 20° glenohumeral abduction. RESULTS: There was a significant decrease in varus deformity caused by the subscapularis (p<0.05) at 20° abduction. Significantly increasing humeral internal rotation decreased varus deformity caused by the subscapularis (p<0.05) at both abduction angles and that caused by the supraspinatus (p<0.05) and infraspinatus (p<0.05) at 0° abduction only. CONCLUSIONS: Postoperative shoulder abduction and internal rotation can be protective against varus failure following proximal humeral fracture fixation as these positions decrease tension on the supraspinatus and subscapularis muscles. Use of a resting sling that places the shoulder in this position should be considered.

Patient- and Process-Related Contributors to the Underuse of Aortic Valve Replacement and Subsequent Mortality in Ambulatory Patients With Severe Aortic Stenosis.

Background Many patients with severe aortic stenosis (AS) and an indication for aortic valve replacement (AVR) do not undergo treatment. The reasons for this have not been well studied in the transcatheter AVR era. We sought to determine how patient- and process-specific factors affected AVR use in patients with severe AS. Methods and Results We identified ambulatory patients from 2016 to 2018 demonstrating severe AS, defined by aortic valve area [Formula: see text]1.0 cm2. Propensity scoring analysis with inverse probability of treatment weighting was used to evaluate associations between predictors and the odds of undergoing AVR at 365 days and subsequent mortality at 730 days. Of 324 patients with an indication for AVR (79.3±9.7 years, 57.4% men), 140 patients (43.2%) did not undergo AVR. The odds of AVR were reduced in patients aged >90 years (odds ratio [OR], 0.24 [95% CI, 0.08-0.69]; P=0.01), greater comorbid conditions (OR, 0.88 per 1-point increase in Combined Comorbidity Index [95% CI, 0.79-0.97]; P=0.01), low-flow, low-gradient AS with preserved left ventricular ejection fraction (OR, 0.11 [95% CI, 0.06-0.21]), and low-gradient AS with reduced left ventricular ejection fraction (OR, 0.18 [95% CI, 0.08-0.40]) and were increased if the transthoracic echocardiogram ordering provider was a cardiologist (OR, 2.46 [95% CI, 1.38-4.38]). Patients who underwent AVR gained an average of 85.8 days of life (95% CI, 40.9-130.6) at 730 days. Conclusions The proportion of ambulatory patients with severe AS and an indication for AVR who do not receive AVR remains significant. Efforts are needed to maximize the recognition of severe AS, especially low-gradient subtypes, and to encourage patient referral to multidisciplinary heart valve teams.

Trends in Utilization of Aortic Valve Replacement for Severe Aortic Stenosis.

BACKGROUND: Despite the rapid growth of aortic valve replacement (AVR) for aortic stenosis (AS), limited data suggest symptomatic severe AS remains undertreated. OBJECTIVES: This study sought to investigate temporal trends in AVR utilization among patients with a clinical indication for AVR. METHODS: Patients with severe AS (aortic valve area <1 cm2) on transthoracic echocardiograms from 2000 to 2017 at 2 large academic medical centers were classified based on clinical guideline indications for AVR and divided into 4 AS subgroups: high gradient with normal left ventricular ejection fraction (LVEF) (HG-NEF), high gradient with low LVEF (HG-LEF), low gradient with normal LVEF (LG-NEF), and low gradient with low LVEF (LG-LEF). Utilization of AVR was examined and predictors identified. RESULTS: Of 10,795 patients, 6,150 (57%) had an indication or potential indication for AVR, of whom 2,977 (48%) received AVR. The frequency of AVR varied by AS subtype with LG groups less likely to receive an AVR (HG-NEF: 70%, HG-LEF: 53%, LG-NEF: 32%, LG-LEF: 38%, P < 0.001). AVR volumes grew over the 18-year study period but were paralleled by comparable growth in the number of patients with an indication for AVR. In patients with a Class I indication, younger age, coronary artery disease, smoking history, higher hematocrit, outpatient index transthoracic echocardiogram, and LVEF ≥0.5 were independently associated with an increased likelihood of receiving an AVR. AVR was associated with improved survival in each AS-subgroup. CONCLUSIONS: Over an 18-year period, the proportion of patients with an indication for AVR who did not receive AVR has remained substantial despite the rapid growth of AVR volumes.

Synergistic effect of the anterolateral ligament and capsule injuries on the knee laxity in anterior cruciate ligament injured knees: A cadaveric study.

INTRODUCTION: There is much controversy about the practical role of the anterolateral ligament (ALL) and its relation to other anterolateral knee structures including the anterolateral capsule (ALC) and iliotibial band (ITB). The purpose of this cadaveric study was to investigate the effect of the ALL and ALC injuries on knee laxity with the iliotibial band (ITB) preserved in the anterior cruciate ligament (ACL)-injured knee. HYPOTHESIS: The ALL and ALC would contribute to knee joint stability during anterior translation and internal rotation of the tibia in an ACL-injured knee. MATERIAL AND METHODS: For 10 fresh-frozen cadaveric knees, we measured knee laxity with the following state of knee injuries with ITB preserved: (1) intact knee, (2) ACL-sectioned knee (ACL-), (3) additional sectioning of the ALL (ACL-/ALL-), and (4) additional sectioning of the ALC (ACL-/ALL-/ALC-). We did biomechanical measurements in internal-external rotation, anterior-posterior translation, and varus-valgus angulation for each condition at knee flexion angles of 0°, 30°, 60°, and 90°. RESULTS: After we sectioned the ALL (ACL-/ALL-), the mean IR at 0°, 30°, 60°, and 90° of knee flexion were significantly increased, compared to the intact knee (p=<0.001, <0.001, <0.001, and 0.002) and ACL- (p=<0.001, <0.001, <0.001, and 0.002). The additional transection of the ALC (ACL-/ALL-/ALC-) significantly increased IR laxity from the ACL-/ALL- at 30°, 60°, and 90° (p=0.005, 0.003, and 0.047). For anterior laxity, ACL-/ALL- resulted in significantly increased anterior laxity from the ACL- at 30° and 60° (p=0.003 and 0.019), and ACL-/ALL-/ALC- significantly increased anterior laxity even from the ACL-/ALL- at 30° and 60° (p=0.007 and 0.011). For varus laxity, ACL-/ALL- resulted in significantly increased varus laxity from both the intact knee and ACL- at 60° (p=0.004 and 0.007) and 90° (p=<0.001 and<0.001). ACL-/ALL-/ALC- resulted in significantly increased varus from ACL-/ALL- at 60° and 90° (p=<0.001 and 0.003). CONCLUSION: The anterolateral ligament and anterolateral capsule injuries in ACL-injured knees even with ITB preserved had a synergistic effect on knee laxity in the aspects of internal rotation, anterior translation, and varus angulation. LEVEL OF EVIDENCE: II, Controlled laboratory study.

Suture Augmentation Neutralizes Deforming Muscular Forces in a Simulated 2-Part Osteoporotic Proximal Humeral Fracture Model.

OBJECTIVES: To evaluate the contribution that tension-relieving sutures, placed between a proximal humeral locking plate and the rotator cuff muscles, had on preventing varus malalignment in an osteoporotic 2-part proximal humerus fracture model. METHODS: A 2-part fracture model was created in 8 cadaveric specimens and then fixed with a lateral locking plate. A custom shoulder testing system was used to increase loading through the supraspinatus (SS) tendon to drive varus deformity. Trials were performed with no suture placement; SS only; SS and subscapularis (SB); and SS, SB, and infraspinatus. The primary outcome was contribution of each point of suture fixation to prevention of varus collapse. RESULTS: Suture augmentation to the SS, SB, and infraspinatus significantly decreased humeral head varus collapse when compared with the plate alone at nearly all loads ( P < 0.05). There were no significant differences in humeral head varus collapse between the 3 suture constructs. CONCLUSIONS: In our biomechanical evaluation of a simulated osteoporotic 2-part proximal humerus fracture with incompetent medial calcar, tension-relieving sutures placed between a lateral locked plate and the rotator cuff tendons prevented varus malalignment.

Muscular Forces Responsible for Proximal Humeral Deformity After Fracture.

OBJECTIVES: To evaluate the contribution of each of the rotator cuff muscles and deltoid to fracture deformity in a 2-part proximal humerus fracture model. Our hypothesis was that superior cuff muscles would have the greatest contribution to coronal plane deformity, whereas muscles with anterior and posterior attachments would have the greatest contribution to axial and sagittal plane deformity. METHODS: A medial wedge osteotomy was created in 8 cadaveric shoulder specimens. A custom shoulder testing system was used to load each rotator cuff muscle and deltoid under increasing loading conditions. Fracture displacement was measured using a Microscribe digitizing system. The primary outcome was the contribution of each muscle to varus collapse. Secondary outcomes included contributions of each muscle to apex anterior/posterior deformity and humeral head anteversion/retroversion. RESULTS: Unbalanced loading of the supraspinatus resulted in the greatest varus deformity (34.5 ± 2.3 degrees), followed by the infraspinatus (22.3 ± 3.6 degrees) and subscapularis (21.7 ± 3.1 degree) (P < 0.05). Unbalanced loading of the subscapularis induced the greatest apex posterior (27.5 ± 4.8 degrees, P < 0.05) and retroversion (39.0 ± 5.6 degrees, P < 0.05) deformity, whereas the infraspinatus induced the greatest apex anterior (8.7 ± 3.4 degrees, P > 0.05) and anteversion (17.7 ± 5.7 degrees, P > 0.05) deformity. CONCLUSIONS: In this proximal humerus fracture model, the supraspinatus was the primary driver of varus deformity, whereas the subscapularis and infraspinatus contributed to apex posterior/retroversion and apex anterior/anteversion, respectively. The subscapularis and infraspinatus are also important secondary drivers of varus deformity. This study establishes a physiologically relevant fracture model that mimics in vivo conditions for future biomechanical testing.

Biomechanical analysis of progressive rotator cuff tendon tears on superior stability of the shoulder.

BACKGROUND: The biomechanical relationship between irreparable rotator cuff tear size and glenohumeral joint stability in the setting of superiorly directed forces has not been characterized. The purpose of this study was to quantify kinematic alterations of the glenohumeral joint in response to superiorly directed forces in a progressive posterosuperior rotator cuff tear model. METHODS: Nine fresh-frozen cadaveric shoulders (mean age; 58 years) were tested with a custom shoulder testing system. Three conditions were tested: intact, stage II (supraspinatus) tear, stage III (supraspinatus + anterior half of infraspinatus) tear. At each condition, range of motion and humeral head positions were measured with a "balanced" loading condition, and with a superiorly directed force ("unbalanced loading condition"). At each of the 0°, 20°, and 40° of glenohumeral abduction positions, all measurements were made at 0°, 30°, 60°, and 90° of external rotation (ER). Two-way repeated measures analysis of variance with Tukey post hoc tests were performed for statistical analyses. RESULTS: With the balanced load, no significant change in superior humeral head position was observed in stage II tears. Stage III tears significantly changed the humeral head position superiorly at 30° and 60° ER at each abduction angle compared with the intact condition (P ≤ .028). With superiorly directed load, stage II and stage III tears both showed statistically significant increases in superior translation at all degrees of ER for all degrees of abduction (P ≤ .035), except stage II tears at 0° ER and 40° abduction (P = .185) compared with the intact condition. Stage II tears showed posterior translations with 30° and 60° ER, both at 20° and 40° of abduction. Stage III tears also showed posterior translations with 90° ER for all abduction angles (P ≤ .039). CONCLUSION: With superiorly directed loads, complete supraspinatus tendon tears created superior translations at all abduction angles, and posterior instability in the middle ranges of rotation for 20° and 40° of abduction. Larger tears involving the anterior half of the infraspinatus tendon caused significant superior and posterior translations within the middle ranges of ER for all abduction angles. In addition to superior instability, posterior translation should be considered when selecting or developing surgical techniques for large posterosuperior rotator cuff tears.