Factors associated with resorption of calcific deposits in the shoulder with extracorporeal shock wave therapy.

BACKGROUND: Focused extracorporeal shock wave therapy (FSWT) is effective for treating calcific tendinitis of the shoulder. However, only a few reports exist on the factors related to calcium resorption after FSWT. Thus, this study aimed to investigate the factors associated with calcium resorption. METHODS: In 117 shoulders with chronic calcific rotator cuff tendinitis, FSWT was administered nine times once every 2 weeks (a total of 16 weeks). After nine sessions of FSWT, the shoulders were radiographed and categorized into complete resorption (CR) and incomplete resorption (ICR) groups. Evaluated parameters included age, duration of disease, Gärtner classification, size of calcium deposits, presence of blood flow around calcium deposits using the Doppler function of the ultrasound imaging system, Japanese Orthopaedic Association (JOA) score, University of California at Los Angeles score, disability of the arm, shoulder, and hand (UCLA) score, and tenderness. RESULTS: The CR group included 93 shoulders (79.4%) and the ICR group included 24 shoulders (20.6%). In the two-arm comparison, CR showed significantly longer disease duration (P=.012) and high tenderness (P=.0013). Blood flow around calcium deposits was observed in 79.5% of shoulders in the CR group (P<.0001) and 29.1% in the ICR group. Type 1 Gärtner classification (P=.0009) was observed in 28 shoulders (30.1%) in the CR group and 17 shoulders (70.8%) in the ICR group. The two groups had no significant differences in age, size of calcium deposits, JOA score, or UCLA score. Multiple logistic regression analysis was performed using the following items that showed significant differences: absence of blood flow (odds ratio [OR], 8.51, 95% confidence interval [CI]: 2.24-22.8), Gärtner classification (OR, 5.60, 95%CI: 1.73-13.3), and duration of disease (OR, 1.06, 95%CI: 0.97-1.26). Longer disease duration, Gärtner type 1, and absence of blood flow around calcium deposits resulted in difficulty in calcium resorption. CONCLUSION: Patients with Gärtner type 1 with prolonged disease duration and absence of blood flow around calcium deposits may have difficulty in achieving complete resorption.

Comparative efficacy of treatments for a first-time traumatic anterior shoulder dislocation: a systematic review and network meta-analysis.

BACKGROUND: First-time traumatic anterior shoulder dislocation (FASD) is a common trauma associated with shoulder dysfunction. Although several randomized controlled trials have compared conservative and surgical treatments for FASD, the comparative efficacy of these treatments is poorly understood. In this network meta-analysis (NMA), we compared the available evidence on the efficacy of various interventions in patients with FASD. METHODS: We searched the Cochrane Central Register of Controlled Trials, MEDLINE, and EMBASE databases in March 2023. This NMA included randomized controlled trials comparing conservative and surgical treatments for FASD, including arthroscopic Bankart repair, arthroscopic lavage, external rotation (ER) immobilization, and internal rotation (IR) immobilization. The primary outcomes were redislocation rates, Western Ontario Shoulder Instability Index (WOSI) scores, and adverse events (AEs). We conducted random-effects NMA within the frequentist framework. To rank the treatments, the Surface Under the Cumulative Ranking curve was calculated using a Bayesian framework. We evaluated confidence in each outcome using the CINeMA tool. RESULTS: Of the 2999 reviewed studies, 15 were included and analyzed. Regarding the primary outcomes, arthroscopic Bankart repair likely results in a large reduction in redislocation rates compared to IR immobilization (risk ratio [RR], 0.15; 95% confidence interval [CI], 0.07-0.33). Both arthroscopic lavage (RR, 0.47; 95% CI, 0.20-1.11) and ER immobilization (RR 0.70; 95% CI, 0.50-1.00) may reduce the redislocation rates slightly compared with IR immobilization. According to these results, arthroscopic Bankart repair ranked first in terms of reducing the redislocation rate, followed by arthroscopic lavage, ER and IR immobilization. Regarding the WOSI score, no substantial differences were observed in the WOSI scores among the four treatments. AEs showed that ER immobilization tended to cause greater shoulder stiffness than IR immobilization, and postoperative erythema, swelling, and adhesive capsulitis were observed after arthroscopic Bankart repair and lavage. However, a meta-analysis was not performed because the definitions of AEs differed between the studies. CONCLUSION: Arthroscopic Bankart repair showed a significant effect in reducing the redislocation rate compared to IR immobilization. Although both arthroscopic lavage and ER immobilization seemed to be effective in reducing the redislocation rates, it was not statistically significant. Moreover, these four treatments may result in little to no difference in disease-specific quality of life and there is no clear evidence of AEs.

Targeting FoxO transcription factors with HDAC inhibitors for the treatment of osteoarthritis.

OBJECTIVES: Osteoarthritis (OA) features ageing-related defects in cellular homeostasis mechanisms in articular cartilage. These defects are associated with suppression of forkhead box O (FoxO) transcription factors. FoxO1 or FoxO3 deficient mice show early onset OA while FoxO1 protects against oxidative stress in chondrocytes and promotes expression of autophagy genes and the essential joint lubricant proteoglycan 4 (PRG4). The objective of this study was to identify small molecules that can increase FoxO1 expression. METHODS: We constructed a reporter cell line with FoxO1 promoter sequences and performed high-throughput screening (HTS) of the Repurposing, Focused Rescue and Accelerated Medchem (ReFRAME) library . Hits from the HTS were validated and function was assessed in human chondrocytes, meniscus cells and synoviocytes and following administration to mice. The most promising hit, the histone deacetylase inhibitor (HDACI) panobinostat was tested in a murine OA model. RESULTS: Among the top hits were HDACI and testing in human chondrocytes, meniscus cells and synoviocytes showed that panobinostat was the most promising compound as it increased the expression of autophagy genes and PRG4 while suppressing the basal and IL-1ß induced expression of inflammatory mediators and extracellular matrix degrading enzymes. Intraperitoneal administration of panobinostat also suppressed the expression of mediators of OA pathogenesis induced by intra-articular injection of IL-1ß. In a murine OA model, panobinostat reduced the severity of histological changes in cartilage, synovium and subchondral bone and improved pain behaviours. CONCLUSION: Panobinostat has a clinically relevant activity profile and is a candidate for OA symptom and structure modification.

Clinical outcomes in patients with retear after arthroscopic rotator cuff repair: A meta-analysis.

BACKGROUND: Rotator cuff retear is a major concern after arthroscopic rotator cuff repair (ARCR); however, the effects of retear remain unclear. Therefore, the purpose of this study was to assess the clinical outcomes of postoperative retear and intact tendons after ARCR. METHODS: We searched PubMed, Cochrane Library, Scopus, and PEDro databases for studies performed from January 2000 to June 2020. Clinical outcomes included the Constant score, American Shoulder and Elbow Surgeons (ASES) score, University of California Los Angeles shoulder (UCLA) score, pain score, range of motion, and muscle strength. Meta-analysis using random-effects models was performed on the pooled results to determine significance. RESULTS: The initial database search yielded 3141 records. After removal of duplicates, 26 of which met the inclusion criteria. Patients in the retear group had significantly lower Constant score [- 8.51 points (95% CI, - 10.29 to - 6.73); P < 0.001], ASES score [- 12.53 points (95% CI, - 16.27 to - 8.79); P < 0.001], UCLA score [- 3.77 points (95% CI, - 4.72 to - 2.82); P < 0.001], and significantly higher pain score [0.56 cm (95% CI, 0.10 to 1.01); P = 0.02] than the intact group. In addition, the retear group had significantly lower flexion [- 10.46° (95% CI, - 19.86 to - 1.07); P = 0.03], abduction [- 14.84° (95% CI, - 28.55 to - 1.14); P = 0.03], and external rotation [- 7.22° (95% CI, - 13.71 to - 0.74); P = 0.03] range of motion, and flexion [- 1.65 kg·f (95% CI, - 2.29 to - 1.01); P < 0.001], abduction [- 1.87 kg·f (95% CI, - 3.02 to - 0.72); P = 0.001], and external rotation [- 1.66 kg·f (95% CI, - 3.25 to - 0.07); P = 0.04] muscle strength. CONCLUSION: Our results suggest that retear after ARCR leads to poor clinical outcomes after surgery.

Combination of risk factors affecting retear after arthroscopic rotator cuff repair: a decision tree analysis.

BACKGROUND: Several risk factors for postoperative retear after arthroscopic rotator cuff repair (ARCR) have been cited in a large number of reports; various combinations of these seem to be present in the clinical setting. PURPOSE: Using a combination model for decision tree analysis, we aimed to investigate the combination of risk factors that affect postoperative retear the most. METHODS: A total of 286 patients who underwent magnetic resonance (MR) imaging at 6 months after surgery were included in this study. Based on the structural integrity of the MR images taken 6 months after surgery, the patients were divided into a healed group (intact tendon, 254 patients) and a retear group (ruptured tendon, 32 patients). Using univariate and decision tree analyses, we selected a combination of 11 risk factors that drastically affected postoperative retear. RESULTS: The mean age was 64.9 ± 7.1 years, and the mean symptom duration was 9.7 ± 11.6 months. The tear was small/medium in 177 patients and large/massive in 109 patients. The technique for surgical repair was single row in 42 patients, double row in 60 patients, and suture bridging in 216 patients. On univariate analysis, both groups had significant differences in the anteroposterior (AP) tear size (P < .0001), mediolateral tear size (P < .0001), hyperlipidemia (P = .0178), global fatty degeneration index (P < .0001), supraspinatus fatty degeneration stage (P < .0001), and critical shoulder angle (CSA) (P = .0015). All of these 5 risk factors, except for mediolateral tear size, were selected as candidates for the decision tree analysis. Eight combination patterns were determined to have prediction probabilities that ranged from 4.3% to 86.1%. In particular, the combination of an AP tear size of ≥40 mm, hyperlipidemia, and a CSA of ≥37° affected retear after ARCR the most. CONCLUSIONS: Decision tree analysis lead to the extraction of different retear factor combinations, which were divided into 5 retear groups. The worst combination was of AP tear size ≥40 mm, hyperlipidemia, and CSA ≥37°, and the prediction probability of this combination was 86.2%. Therefore, our data may offer a new index for the prediction of retear after ARCR.

Editorial Commentary: Revision Surgery After Symptomatic Failed Arthroscopic Rotator Cuff Repair: What Factors Affect Primary Surgery?

Anteroposterior tear length, hyperlipidemia, and muscle fatty degeneration lead to retear after arthroscopic rotator cuff repair and to subsequent revision surgery. The challenge is to develop methods to prevent these adverse effects after surgery.

Representative survey of frozen shoulder questionnaire responses from the Japan Shoulder Society: What are the appropriate diagnostic terms for primary idiopathic frozen shoulder, stiff shoulder or frozen shoulder?

BACKGROUND: Primary frozen shoulder has unknown etiology and significant restriction of active and passive motion. The distinction between frozen shoulder and stiff shoulder has been unclear. Therefore, the purposes of this study were to perform a survey regarding definition and classification of frozen shoulder proposed by the American Academy of Orthopedic Surgeons (AAOS) among the members of the Japan Shoulder Society (JSS) and to compare the results with those obtained among the members of the American Shoulder and Elbow Surgeons (ASES). METHODS: The Scientific Research Project Committee of the JSS prepared the questionnaire for frozen shoulder and stiff shoulder. Surveys were sent by e-mail on Jan 14, 2016 to JSS registered members and the response dead-line was set on March 13, 2016. RESULTS: The number of respondents was 230, including all directors, councilors, and senior doctors. Agreement with the definition of primary frozen shoulder was 67%, the classification of primary or secondary frozen shoulder was 53%, and the 3 divisions of secondary frozen shoulder was 53%. Diagnostic terms for the cases of shoulder stiffness with unknown etiology were as follows: frozen shoulder (31%), stiff shoulder (22%), periarthritis scapulohumeralis (16%), so called "Gojukata" in Japan, which means shoulder problems in their fifties (16%), idiopathic frozen shoulder (6%), primary frozen shoulder (4%), adhesive capsulitis (3%), others (2%). CONCLUSION: The survey shows lower rates of agreement among the JSS members than the ASES members for the definition of primary frozen shoulder, the classification of primary and secondary frozen shoulder, and the divisions of secondary frozen shoulder. To avoid confusion between stiff shoulder and frozen shoulder, the committee agrees to the ISAKOS recommendation that the term "frozen shoulder" should be used exclusively for primary idiopathic stiff shoulder.

Hand lesion after arthroscopic rotator cuff repair: Association with complex regional pain syndrome.

BACKGROUND: It is known that complex regional pain syndrome (CRPS) occurs after arthroscopic rotator cuff repair (ARCR); however, few studies have investigated this complication. Therefore, the purpose of the present study was to evaluate CRPS after ARCR. METHODS: A total of 182 patients who underwent ARCR were enrolled in this study. The average age of patients was 62.8 ± 10.0 years, with an average follow-up period of 21.5 ± 38.1 months. CRPS criteria outlined by the Ministry of Health, Labor, and Welfare study team for CRPS in Japan (MHLWJ) and International Association for the Study of Pain (IASP 2005) were utilized for diagnosis. There are two rating systems for the "clinical purpose" and "research purpose" in both criteria, respectively. Clinical outcomes, including Japanese Orthopedic Association (JOA) and University of California, Los Angeles scores, were evaluated using univariate and multivariate analysis. RESULTS: CRPS exclusively occurred in the hand of the operated limb, developing within 3 months of surgery. Two or more of the following symptoms were noted in patients with the hand lesion associated with CRPS: edema (93.4%), restricted range of motion (83.4%), hyperalgesia (30.1%), paridrosis (20.4%), and atrophic change (12.2%). Under these conditions, the incidences of CRPS were 24.2% (44/182) when evaluated by the MHLWJ rating system for the "clinical purpose;" 11% (22/182) by the MHLWJ rating system for the "research purpose;" 6% (11/182) by the IASP 2005 for the "clinical purpose;" and 0.5% (1/182) by the IASP 2005 for the "research purpose." Results of multivariate analysis demonstrated that "Function" in the JOA score was a risk factor for the development of CRPS after ARCR, when evaluated by a system for the "clinical purpose" of the MHLWJ. CONCLUSION: Following ARCR, CRPS-induced hand lesions occur more frequently than is generally believed, thereby suggesting that its impact on surgical outcomes should be clarified in the future.

Cutoff value of Japanese Orthopaedic Association shoulder score in patients with rotator cuff repair: Based on the University of California at Los Angeles shoulder score.

BACKGROUND: The Japanese Orthopaedic Association shoulder score cutoff values were calculated in patients with rotator cuff repair using the University of California at Los Angeles shoulder score. METHODS: Overall, 175 patients with rotator cuff repair were subjects in this study. The University of California at Los Angeles and Japanese Orthopaedic Association shoulder scores were evaluated before surgery and at 3, 6, 9, and 12 months after surgery. The cutoff value of the Japanese Orthopaedic Association shoulder score was determined using the 4-stage criteria of the University of California at Los Angeles shoulder score and a University of California at Los Angeles shoulder score of 28 points, which is the boundary between an excellent/good group and a fair/poor group. RESULTS: Both the JOA shoulder and UCLA shoulder scores showed significant improvement at 6, 9, and 12 months from the preoperative scores (p < 0.0001). There was a strong correlation between the total values of the two scores (r = 0.85, p < 0.0001). The cutoff value of the Japanese Orthopaedic Association shoulder score based on the highest accuracy from receiver operating characteristic curve analysis was 83 points. CONCLUSION: A Japanese Orthopaedic Association shoulder score cutoff value of 83 was equivalent to a University of California at Los Angeles shoulder score cutoff value of 28 for distinguishing between excellent/good and fair/poor outcomes after rotator cuff repair.

Factors Affecting Clinical Outcome in Patients With Structural Failure After Arthroscopic Rotator Cuff Repair.

PURPOSE: (1) To compare clinical outcomes between patients with large or massive rotator cuff tears who have healed cuffs and patients with postoperative structural failure (retear after complete or partial repair) and (2) to identify factors associated with clinical outcomes in patients with postoperative structural failure. METHODS: We conducted a retrospective study of consecutive patients with large or massive cuff tears who underwent arthroscopic repair at our institution between 2005 and 2012. On the basis of intraoperative findings and magnetic resonance imaging at final follow-up, the patients were divided into 3 groups: healed group, retear group (after complete repair), and partial-repair group. The outcome measures comprised the Japanese Orthopaedic Association (JOA) and University of California, Los Angeles (UCLA) scores; muscle strength; and range of motion. The tear length, tear width, muscle atrophy, and fatty degeneration were evaluated by preoperative and postoperative magnetic resonance imaging. The extent of tendon reattachment to the superior, middle, and inferior facets and the lesser tuberosity was examined on magnetic resonance images at final follow-up. RESULTS: In total, 74 patients (healed, 41; retear, 19; and partial repair, 14) were included in this study. The mean age was 63.8 ± 8.5 years, with a mean follow-up period of 3.6 ± 1.4 years. The postoperative JOA and UCLA scores significantly improved in all 3 groups, but the differences were not significant. In the retear and partial-repair groups, postoperative tendon preservation at the middle facet significantly affected the JOA and UCLA scores (P = .003 and P = .014, respectively). CONCLUSIONS: The JOA and UCLA scores were significantly improved in patients with structural failure. Under these conditions, the only clinical factor that affected patient outcome was tendon healing at the middle facet. Thus tendon preservation at the middle facet was a predictor of good clinical outcomes in patients who underwent arthroscopic rotator cuff repair of large or massive tears and had postoperative structural failure. LEVEL OF EVIDENCE: Level III, case-control study.

Analysis of scapular kinematics during active and passive arm elevation.

[Purpose] Early postoperative passive motion exercise after arthroscopic rotator cuff repair remains controversial. To better understand this issue, this study was aimed at evaluating scapular kinematics and muscle activities during passive arm elevation in healthy subjects. [Subjects and Methods] The dominant shoulders of 27 healthy subjects were examined. Electromagnetic sensors attached to the scapula, thorax, and humerus were used to determine three-dimensional scapular kinematics during active arm elevation with or without external loads and passive arm elevation. Simultaneously, the activities of seven shoulder muscles were recorded with surface and intramuscular fine-wire electrodes. [Results] Compared with active arm elevation, passive elevation between 30° and 100° significantly decreased the scapular upward rotation and increased the glenohumeral elevation angle. However, no significant differences in scapular posterior tilt and external rotation were observed between active and passive arm elevation, and scapular plane kinematics were not affected by muscle activity. [Conclusion] Unlike active motion with or without an external load, passive arm elevation significantly decreased the scapular upward rotation and significantly increased the mid-range glenohumeral elevation. These data, which suggest that passive arm elevation should be avoided during the early postoperative period, may expand the understanding of rehabilitation after arthroscopic rotator cuff repair.

Rapid collapse of the humeral head after arthroscopic rotator cuff repair.

UNLABELLED: This report presents a case of rapidly progressive collapse of the humeral head following arthroscopic rotator cuff repair. We performed humeral head replacement 8 months after the index surgery; histological examination of the collapsed area revealed necrosis, degeneration, fibrillation, and granulation in the cartilage and trabeculae. Osteonecrosis due to the use of metal anchors was considered the primary cause of the post-operative humeral head collapse. As the demand for arthroscopic cuff repair is expected to increase in the future, we recommend that surgeons become aware of the potential for complications, as seen in the present case. LEVEL OF EVIDENCE: IV.

Effects of adipose-derived cell supplementation on tendon-bone healing in a rat model of chronic rotator cuff tear with suprascapular nerve injury.

OBJECTIVE: To investigate the effect of adipose-derived cells (ADCs) on tendon-bone healing in a rat model of chronic rotator cuff tear (RCT) with suprascapular nerve (SN) injury. METHODS: Adult rats underwent right shoulder surgery whereby the supraspinatus was detached, and SN injury was induced. ADCs were cultured from the animals' abdominal fat. At 6 weeks post-surgery, the animals underwent surgical tendon repair; the ADC (+ve) group (n = 18) received an ADC injection, and the ADC (-ve) group (n = 18) received a saline injection. Shoulders were harvested at 10, 14, and 18 weeks and underwent histological, fluorescent, and biomechanical analyses. RESULTS: In the ADC (+ve) group, a firm enthesis, including dense mature fibrocartilage and well-aligned cells, were observed in the bone-tendon junction and fatty infiltration was less than in the ADC (-ve) group. Mean maximum stress and linear stiffness was greater in the ADC (+ve) compared with the ADC (-ve) group at 18 weeks. CONCLUSION: ADC supplementation showed a positive effect on tendon-bone healing in a rat model of chronic RCT with accompanying SN injury. Therefore, ADC injection may possibly accelerate recovery in massive RCT injuries.

Increased matrix metalloprotease-3 gene expression in ruptured rotator cuff tendons is associated with postoperative tendon retear.

PURPOSE: The role of matrix metalloproteases (MMPs) in ruptured rotator cuff tendons remains unknown. This study aimed to investigate the gene expression of MMPs in ruptured rotator cuff tendons and to compare their expression levels between patients with and without postoperative tendon retear. METHODS: Twenty-four patients (a median age of 61 years: interquartile range, 55-66 years) with full-thickness rotator cuff tears were examined in this study. The marginal site of the ruptured tendon was harvested during surgery. The mRNA expression levels of collagen types I and III, MMP-1, MMP-3, MMP-7, MMP-9, MMP-13, tissue inhibitor of MMP (TIMP)-1, and TIMP-2 were analysed by real-time reverse transcription polymerase chain reaction. Postoperative retear was evaluated by magnetic resonance imaging at a minimum of 1 year following surgery. RESULTS: The mRNA expression levels of MMP-3 and TIMP-1 in ruptured rotator cuff tendons were significantly increased in patients with postoperative retear (n = 6), compared with patients without retear (n = 18) (P = 0.04). For collagens, MMP-1, MMP-7, MMP-9, MMP-13, and TIMP-2, there were no significant differences in the mRNA expression levels in ruptured tendons between patients with and without retear. CONCLUSIONS: These results suggest that, in addition to up-regulation of TIMP-1 gene expression, increased MMP-3 gene expression in ruptured rotator cuff tendons is associated with postoperative tendon retear. Thus, drug therapy specifically targeting MMP-3 after rotator cuff repair should be considered in the future.

Does physiotherapy after rotator cuff repair require supervision by a physical therapist?: a meta-analysis.

BACKGROUND: A supervised physiotherapy program (SPP) is a standard regimen after surgical rotator cuff repair (RCR); however, the effect of a home-based exercise program (HEP), as an alternative, on postoperative functional recovery remains unclear. Therefore, the purpose of this meta-analysis was to compare the functional effects of SPP and HEP after RCR. METHODS: We searched electronic databases including Central, Medline, and Embase in April 2022. The primary outcomes included the Constant score, American Shoulder and Elbow Surgeons score, University of California Los Angeles shoulder score, and pain score. Secondary outcomes included range of motion, muscle strength, retear rate, and patient satisfaction rate. A meta-analysis using random-effects models was performed on the pooled results to determine the significance. RESULTS: The initial database search yielded 848 records, five of which met our criteria. Variables at 3 months after surgery were successfully analyzed, including the Constant score (mean difference, -8.51 points; 95% confidence interval [CI], -32.72 to 15.69; P=0.49) and pain score (mean difference, 0.02 cm; 95% CI, -2.29 to 2.33; P=0.99). There were no significant differences between the SPP and HEP. Other variables were not analyzed owing to the lack of data. CONCLUSIONS: Our data showed no significant differences between SSP and HEP with regard to the Constant and pain scores at 3 months after RCR. These results suggest that HEP may be an alternative regimen after RCR. Level of evidence: I.

Postoperative Rotation Deformity of Head-Neck Fragments in Unstable Intertrochanteric Fractures Fixed with Intramedullary Nails.

BACKGROUND: Our purpose was to quantify the postoperative rotation deformity (RD) after osteosynthesis of unstable intertrochanteric fractures (ITFx) using 3D-CT / image processing software, and to clarify the clinical meaning of RD. METHODS: Forty-six consecutive patients with unstable intertrochanteric fractures were enrolled in this study. All were fixed with Gamma 3 Trochanteric nail and RC Lag Screw® (Stryker). We performed 3D-CT evaluations for the rotational deformity of head-neck fragments, the medial cortex support (MCS) between main fragments and bone healing at 3 months postoperatively. RESULTS: The RD was significantly larger in the patients without the MCS (5.1 ± 4.0°, N = 9) than those with the MCS (2.4 ± 2.6°, N = 37) (P = 0.006*). Delayed healing (N=3) was observed in patients without the MCS, and the association between RD and delayed healing was significant (P = 0.003*, cut-off value 6.4°, sensitivity 100% and specificity 90.7%, AUC 0.91). CONCLUSIONS: This study proposed a novel method of measuring postoperative RD. Lack of MCS may lead to RD and consequent delayed healing in unstable ITFx fixed with intramedullary nails.

Effect of suprascapular nerve injury on muscle and regenerated enthesis in a rat rotator cuff tear model.

BACKGROUND: Massive rotator cuff tears (RCTs) are complicated by muscle atrophy, fibrosis, and intramuscular fatty degeneration, which are associated with postoperative tendon-to-bone healing failure and poor clinical outcomes. We evaluated muscle and enthesis changes in large tears with or without suprascapular nerve (SN) injury in a rat model. METHODS: Sixty-two adult Sprague-Dawley rats were divided into SN injury (+) and SN injury (-) groups (n=31 each), comprising tendon (supraspinatus [SSP]/infraspinatus [ISP]) and nerve resection and tendon resection only cases, respectively. Muscle weight measurement, histological evaluation, and biomechanical testing were performed 4, 8, and 12 weeks postoperatively. Ultrastructural analysis with block face imaging was performed 8 weeks postoperatively. RESULTS: SSP/ISP muscles in the SN injury (+) group appeared atrophic, with increased fatty tissue and decreased muscle weight, compared to those in the control and SN injury (-) groups. Immunoreactivity was only positive in the SN injury (+) group. Myofibril arrangement irregularity and mitochondrial swelling severity, along with number of fatty cells, were higher in the SN injury (+) group than in the SN injury (-) group. The bone-tendon junction enthesis was firm in the SN injury (-) group; this was atrophic and thinner in the SN injury (+) group, with decreased cell density and immature fibrocartilage. Mechanically, the tendon-bone insertion was significantly weaker in the SN injury (+) group than in the control and SN injury (+) groups. CONCLUSIONS: In clinical settings, SN injury may cause severe fatty changes and inhibition of postoperative tendon healing in large RCTs. Level of evidence: Basic research, controlled laboratory study.

Infraspinatus fatigue during resisted arm elevation with isometric contraction: an electromyographic study.

BACKGROUND: Various forms of resistance are used in rotator cuff training programs. However, the muscular activity of the infraspinatus during arm elevation has not been clarified in detail. We aimed to evaluate infraspinatus fatigue during resisted arm elevation in various positions. METHODS: The dominant (right) shoulders of 39 healthy subjects were examined. Average mean power frequency shifts of the infraspinatus and deltoid were evaluated electromyographically when the subjects performed isometric contractions equivalent to 30% of the maximal voluntary isometric contraction force for 60 s during 90° arm elevation in the sagittal and scapular planes, prone and side-lying external rotations, and repeated side-lying external rotation exercise. Further, the arm-elevation force was measured before and after the repeated external rotation exercise. Analysis of variance and paired t tests were used for statistical analyses; differences at P < .05 were considered significant. RESULTS: The infraspinatus was fatigued easily during resisted arm elevation in the sagittal plane compared with the scapular plane (P < .01). Comparisons of sagittal-plane elevation with side-lying and prone external rotations revealed no significant differences in the fatigue levels. The arm-elevation force after the repeated external rotations was significantly decreased in the sagittal plane compared with the scapular plane (P < .01). CONCLUSION: In clinical settings, this data may be helpful in knowing how to helpful to protect the infraspinatus after surgical repair. Therefore, therapeutic exercise regimes with resisted arm elevation should avoid infraspinatus overfatigue in the sagittal plane in the early postoperative period.

The clinical outcomes of infraspinatus rotational transfer for irreparable posterosuperior rotator cuff tears: a preliminary report.

BACKGROUND: This study aimed to examine the preliminary clinical results of the infraspinatus rotational transfer procedure for irreparable posterosuperior rotator cuff tears. METHODS: This study included 34 patients (mean age, 68.4 years). Their mean tear width and length measurements were 50.9 mm and 50.6 mm, respectively. The functional outcomes, including physician-determined and patient-reported scores, were evaluated before and at 1 year after surgery. The structural outcomes determined using the magnetic resonance imaging examination results were also assessed. RESULTS: The clinical scores significantly improved after surgery compared with the scores before surgery: the Constant-Murley score (53.3±21.1 to 76.8±10.5), University of California at Los Angeles Shoulder score (15.6±3.6 to 27.8±6.7), American Shoulder and Elbow Surgeons Shoulder score (51.8±18.3 to 89.1±13.5), and WORC score (925.0±436.8 to 480.3±373.2) (all p<0.001). Postoperative re-tears were noted in two patients (5.9%). CONCLUSIONS: One year postoperatively, the patient's clinical scores significantly improved, with a re-tear rate of 5.9%.

Posterior decentering of the humeral head in patients with arthroscopic rotator cuff repair.

BACKGROUND: In some patients with rotator cuff tear (RCT), the axial view of magnetic resonance imaging (MRI) shows subtle posterior decentering (PD) of the humeral head from the glenoid fossa. This is considered to result from a loss of centralization that is typically produced by rotator cuff function. There are few reports on PD in RCT despite the common occurrence of posterior subluxation in degenerative joint disease. In this study, we investigated the effect of PD in arthroscopic rotator cuff repair (ARCR). METHODS: We conducted a retrospective study of consecutive patients who underwent ARCR at our institute and were followed-up for at least 1 year. PD was identified as a 2-mm posterior shift of the humeral head relative to the glenoid fossa in the axial MRI view preoperatively. The tear size and fatty degeneration (FD, Goutallier classification) were also evaluated using preoperative MRI. Retears were evaluated through MRI at 1 year postoperatively. RESULTS: We included 135 shoulders in this study. Ten instances of PD (including seven retears) were observed preoperatively. Fifteen retears (three and 12 retears in the small/medium and large/massive tear groups, respectively) were observed postoperatively. PD was significantly correlated with tear size, FD, and retear occurrence (p<0.01 each). The odds ratio for PD in retears was 34.1, which was greater than that for tear size ≥3 cm and FD grade ≥3. CONCLUSIONS: We concluded that large tear size and FD contribute to the occurrence of PD. Furthermore, PD could be a predictor of retear after ARCR.