Clinical analysis of the acromial height-measuring device combined with new-type clavicular hook plate and standard clavicular hook plate in the treatment of Neer type II distal clavicle fractures.

BACKGROUND: Distal clavicular fracture is a shoulder joint injury that is common in clinical settings and is generally surgically treated using the clavicular hook plate technique with a confirmed curative effect. However, symptoms, such as shoulder abduction limitation, shoulder discomfort, and postoperative joint pain, may occur in some patients. To overcome these problems, after a previous study we developed an acromial height-measuring device and a new type of clavicular hook plate. This study aimed to investigate whether an acromial height-measuring device combined with an improved new-type clavicular hook plate can better reduce the incidence of complications and improve postoperative function. To provide patients with better treatment effects, an acromion gauge and clavicular hook plate are used. METHODS: A retrospective analysis was performed on 81 patients with distal clavicular fractures admitted to our hospital. They were divided into experimental and control groups according to different plates, and the Constant-Murley score, visual analogue scale score, incidence of acromion osteolysis, and incidence of subacromial impingement syndrome were compared. RESULTS: Compared with the standard clavicular hook plate, the acromial height-measuring device combined with the new-type clavicular hook plate in the treatment of distal clavicle fractures has a lower incidence of subacromial impingement syndrome with better postoperative functional recovery and quality of life. CONCLUSIONS: We considered the acromial height-measuring device combined with the new clavicular hook plate to be a safe and promising alternative to distal clavicular fractures.

Posteroinferior relevant scapular neck offset in reverse shoulder arthroplasty: key player for motion and friction-type impingement in a computer model.

BACKGROUND: Range of motion (ROM) and prevention of notching remain a challenge for reverse shoulder arthroplasty (RSA). Both may be affected by the morphology of the scapula. The purpose of this study was to define anteroinferior (a) and posteroinferior (p) relevant scapular neck offset (RSNO) and to examine the hypothesis that pRSNO is significantly smaller than aRSNO, and influences rigid body motion (RBM). Adapting glenosphere implantation strategies may therefore be of value. MATERIAL AND METHODS: In this computer model study, we used deidentified computed tomographic scans of 22 patients (11 male and 11 female; mean age: 72.9 years) with massive cuff tears without joint space narrowing. Eight RSA glenoid configurations were tested with a constant neck-shaft angle (145°). Two baseplate types (25 mm; 25 + 3 mm lateralized) and 4 glenospheres (GS) (36 mm; 36 +2 mm of eccentricity; 39 mm; 39 + 3 mm) were used. RSNO was defined as the standardized measurement of the horizontal distance from the inferior extent of the GS to the bony margin of the scapula after baseplate positioning (flush to inferior glenoid extent; neutral position: 0° inclination and 0° version-both software computed). RESULTS: There was a highly significant difference between pRSNO and aRSNO for both genders (P < .001). pRSNO was always smaller than aRSNO. pRSNO was strongly correlated with external rotation (ERO: 0.84) and extension (EXT: 0.74) and moderately correlated with global ROM (GROM: 0.68). There was a moderately strong correlation between aRSNO and internal rotation (IRO: 0.69). pRSNO was strongly correlated with aRSNO, EXT, ERO, IRO, adduction (ADD) and GROM (0.82, 0.72, 0,8, 0.71, 0.82, 0.76) in female patients and with EXT and ERO (0.82, 0.89) in male patients. The median pRSNO allowing for at least 45° ERO and 40° EXT was 14.2 mm for men and 13.8 mm for women. For all patients and models, pRSNO ≥14 mm increased EXT, ERO, and GROM significantly compared with pRSNO <14 mm (P < .001). The combination of lateralization and inferior overhang (eccentricity) led to the most significant increase of pRSNO for each GS size (P < .001). CONCLUSION: This is one of the first RSA modeling studies evaluating nonarthritic glenoids of both genders. The lateral scapular extent to glenoid relationship is asymmetric. pRSNO is always smaller than aRSNO for both genders and was a critical variable for EXT and ERO, demonstrating additional strong correlation with aRSNO, IRO, ADD, and GROM in female patients. pRSNO ≥14 mm was a safe value to prevent friction-type impingement. Combining increased glenosphere size, lateralization, and inferior overhang gives the best results in this computer-simulated setting.

Evaluating the role of subacromial impingement in rotator cuff tendinopathy: development and analysis of a novel rat model.

BACKGROUND: Subacromial impingement of the rotator cuff caused by variations in acromial anatomy or altered glenohumeral kinematics leads to inflammation and degeneration of the rotator cuff, ultimately contributing to the development of tendinopathy. However, the underlying cellular and molecular changes in the impinged tendon remain poorly understood. Because the rat is an accepted model for rotator cuff studies, we have developed a rat model to study rotator cuff tendinopathy. METHODS: Forty-four adult male Sprague-Dawley rats were allocated to one of 4 study groups: intact control group (group 1, n = 11); bilateral subacromial surgical clip placement to induce supraspinatus impingement for 2 weeks (group 2, n = 11), 4 weeks (group 3, n = 11), and 8 weeks (group 4, n = 11). Bilateral shoulder specimens were harvested for biomechanical testing, histology, and quantitative real-time polymerase chain reaction (qRT-PCR) analysis. RESULTS: Radiography confirmed that all microvascular clips remained in stable position in the subacromial space. Gross inspection of supraspinatus tendon specimens in the impingement groups revealed changes in tendon morphology at the enthesis and midsubstance. Biomechanical evaluation demonstrated decreased supraspinatus tendon failure force and tissue stiffness at all time points compared with control tendons. Semiquantitative scoring of histologic specimens demonstrated significant, persistent tendinopathic changes over 8 weeks. qRT-PCR analysis of impinged tendon specimens demonstrated upregulation of gene expression for Col3 and Mmp14 in the impingement groups compared with control groups. In muscle samples, significant upregulation was seen in the expression of genes that are commonly associated with muscle atrophy (MuRF1 and Ube2b) and fatty infiltration (Fabp4, Pparg2, and Klf15). CONCLUSION: This new rat subacromial impingement model creates cellular and molecular changes consistent with the development of rotator cuff tendinopathy. The results of this study may serve as a baseline for future investigation.

Open plate fixation versus nailing for humeral shaft fractures: a meta-analysis and systematic review of randomised clinical trials and observational studies.

PURPOSE: This meta-analysis compares open reduction and internal fixation with a plate (ORIF) versus nailing for humeral shaft fractures with regard to union, complications, general quality of life and shoulder/elbow function. METHODS: PubMed/Medline/Embase/CENTRAL/CINAHL was searched for observational studies and randomised clinical trials (RCT). Effect estimates were pooled across studies using random effects models. Results were presented as weighted odds ratio (OR) or risk difference (RD) with corresponding 95% confidence interval (95% CI). Subgroup analysis was performed stratified for study design (RCTs and observational studies). RESULTS: Eighteen observational studies (4906 patients) and ten RCT's (525 patients) were included. The pooled effect estimates of observational studies were similar to those obtained from RCT's. More patients treated with nailing required re-intervention (RD 2%; OR 2.0, 95% CI 1.0-3.8) with shoulder impingement being the most predominant indication (17%). Temporary radial nerve palsy secondary to operation occurred less frequently in the nailing group (RD 2%; OR 0.4, 95% CI 0.3-0.6). Notably, all but one of the radial nerve palsies resolved spontaneously in each groups. Nailing leads to a faster time to union (mean difference - 1.9 weeks, 95% CI - 2.9 to - 0.9), lower infection rate (RD 2%; OR 0.5, 95% CI 0.3-0.7) and shorter operation duration (mean difference - 26 min, 95% CI - 37 to - 14). No differences were found regarding non-union, general quality of life, functional shoulder scores, and total upper extremity scores. CONCLUSION: Nailing carries a lower risk of infection, postoperative radial nerve palsy, has a shorter operation duration and possibly a shorter time to union. Shoulder impingement requiring re-intervention, however, is an inherent disadvantage of nail fixation. Notably, absolute differences are small and almost all patients with radial nerve palsy recovered spontaneously. Satisfactory results can be achieved with both treatment modalities.

Influential factors of subacromial impingement syndrome after hook plate fixation for acromioclavicular joint dislocation: A retrospective study.

ABSTRACT: Subacromial impingement syndrome (SIS) after hook plate fixation for acromioclavicular joint (AC) dislocation was the most common complication. However, the researches on its' influential factors were rare. The purpose of this study was to identify the risk factors by analyzing the influencing factors of postoperative SIS and minimize the incidence of SIS in clinical surgery.We retrospectively analyzed the prospectively collected data from 330 consecutive patients with AC joint dislocation between August 2014 and August 2017 at our institute. The SIS was presented as the dependent variable at the last follow-up when the internal fixation was removed. The independent variables included age, gender, body-mass index (BMI), smoking status, alcohol consumption, type of injury, Rockwood Classification, site of injury, operation time, injury-to-surgery, the distance between the hook body and the acromion (DBA), the depth of hook tip (DHT), the distance between the hook plate and the humeral head (DHH), the distance between the acromion and the humeral head (DAH), the hook plate angle (AHP) and acromial shape. Logistic regression analysis was performed to identify independent influential factors of SIS.A total of 312 cases were included and 18 cases were lost. The follow-up rate was 94.5%. In without SIS group, there were 225 cases (123 males and 102 females). In with SIS group, a total of 87 cases were included (56 males and 31 females). The incidence of SIS was 27.8%. DHT (OR = 9.385, 95% CI = 4.883 to 18.040, P < .001) and DBA (OR = 2.444, 95% CI = 1.591 to 3.755, P < .001) were the significant independent risk factor for SIS of AC dislocation treat with hook plate. DAH (OR = 0.597, 95% CI = 0.396 to 0.900, P = .014) and acromial shape with flat and straight (OR = 0.325, 95% CI = 0.135 to 0.785, P = .012) were also independent factors of SIS, but they were all protective.The SIS had a high incidence in fixation of clavicular hook plate for AC dislocation. DHT and DBA were two independent risk factors, DAH and acromial shape with flat and straight were two independent protective factors for SIS. In clinical surgery, we should avoid risk factors to reduce the incidence of SIS.

To explore the reasonable selection of clavicular hook plate to reduce the occurrence of subacromial impingement syndrome after operation.

BACKGROUND: Acromioclavicular joint dislocation is a shoulder joint injury common in the clinical setting and is generally surgically treated with clavicular hook plate technique with confirmed curative effect. However, symptoms such as shoulder abduction limitation, shoulder discomfort and joint pain postoperatively may occur in some patients. Therefore, this study aimed to explore whether the existing clavicular hook plate can be reasonably selected to reduce the incidence of subacromial impingement syndrome (SIS) and provide a reference for clinical diagnosis and treatment. MATERIALS AND METHODS: Patients with SIS admitted from March 2018 to June 2020 were selected as the experimental group and asymptomatic patients postoperatively, as the control group. The hook end depth and acromial height of the hook plate used in patients were recorded, and the difference between them was calculated. RESULTS: The difference between the hook plate depth and acromial height was 7.500±1.912 mm and 6.563±1.537 mm in the experimental and control groups, respectively, with statistically significant difference (t=3.021, P=0.006). A difference of >0.6 mm as a grouping index is required to perform a single factor analysis, with statistically significant difference (t=3.908, P=0.048). CONCLUSIONS: The occurrence of SIS after placing the clavicular hook plate may be related to the difference between its depth and the acromial height. A difference of >6 mm may be a factor affecting the occurrence of SIS. Pre-imaging measurement of the acromial height can provide suggestions for selecting the type of hook plate intraoperatively.

Assessment of Mitochondrial Dysfunction in a Murine Model of Supraspinatus Tendinopathy.

BACKGROUND: The purpose of this study was to assess mitochondrial dysfunction in a murine model of supraspinatus tendinopathy. METHODS: Eighty-four mice (168 limbs) were included in the study. Supraspinatus tendinopathy was induced by inserting a microsurgical clip in the subacromial space of 63 mice bilaterally (126 limbs). Forty-two of these limbs were harvested at 4 weeks postoperatively, 42 underwent clip removal at 4 weeks after the initial procedure and were harvested at 2 weeks, and 42 underwent clip removal at 4 weeks and were harvested at 4 weeks. Forty-two limbs in the remaining 21 mice did not undergo surgical intervention and were utilized as the control group. Outcomes included biomechanical, histological, gene expression, superoxide dismutase (SOD) activity, and transmission electron microscopy (TEM) analyses. RESULTS: Radiographs confirmed stable clip position in the subacromial space at 4 weeks. Biomechanical testing demonstrated a 60% decrease in failure force of the supraspinatus tendons at 4 weeks compared with the control group. The failure force gradually increased at 2 and 4 weeks after clip removal. Histological analysis demonstrated inflammation surrounding the tendon with higher modified Bonar scores at 4 weeks after clip placement followed by gradual improvement following clip removal. The expression of mitochondrial-related genes was decreased at 4 weeks after clip placement and then significantly increased after clip removal. SOD activity decreased significantly at 4 weeks after clip placement but increased following clip removal. TEM images demonstrated alterations in morphology and the number of mitochondria and cristae at 4 weeks after clip placement with improvement after clip removal. CONCLUSIONS: Mitochondrial dysfunction appears to be associated with the development of tendinopathy. CLINICAL RELEVANCE: Mitochondrial protection may offer a potential strategy for delaying the development of tendinopathy and promoting tendon healing.

The acromion-greater tuberosity impingement index: A new radiographic measurement and its association with rotator cuff pathology.

PURPOSE: Several radiographic parameters describe humeral head coverage by the acromion. We describe a new radiographic measurement, the acromion-greater tuberosity impingement index (ATI), and its ability to predict rotator cuff pathology. METHODS: The ATI was measured with magnetic resonance imaging (MRI) and X-ray analysis in 83 patients with rotator cuff pathology and 76 patients with acute rotator cuff tears. The lateral acromial angle (LAA), acromion type, the acromion index (AI) and the critical shoulder angle (CSA) were measured to assess their correlations with the ATI. Receiver operating characteristic (ROC) curves were used to predict degenerative rotator cuff pathology. The change in the ATI after acromion surgery was evaluated in both groups. RESULTS: According to the ROC curves, the ATI is a good predictor of degenerative rotator cuff pathology on both X-ray (cut-off, 0.865) and MRI (cut-off, 0.965). Patients with degenerative rotator cuff pathology had a significantly higher average ATI compared to the trauma group (p = 0.001 for X-ray and MRI). The degenerative group had a significantly lower LAA (p = 0.001) and a higher ratio of type III acromion (p = 0.035) than the trauma group. The ATI on X-ray was negatively related to the LAA and positively related to the AI, the CSA and acromion type (each p < 0.05). The ATI on MRI was negatively related to the LAA and positively related to the AI and acromion type (each p <0.05). More patients in the degenerative group than the trauma group needed acromioplasty or acromion decompression (p < 0.05). The ATI on MRI was significantly lower after acromion surgery compared to before surgery in both groups (p < 0.05). CONCLUSION: The ATI is a good predictor of degenerative supraspinatus tendon tears or subacromial impingement syndrome. The ATI on MRI is more accurate and can precisely guide acromion surgery.

Is antegrade nailing a proper option in 2- and 3-part proximal humeral fractures?

PURPOSE: To report our experience with antegrade short locked intramedullary nail for treatment of proximal humeral fractures and to review the current literature. MATERIALS AND METHODS: From January 2012 to July 2013, 41 patients affected by two and three-part proximal humeral fractures were treated with surgical internal fixation with short locked intramedullary nails. Outcome analysis included standard clinical follow-up, Constant shoulder score and plain radiographs. The mean follow-up was 30 months (range 24-42). Moreover, a review of the literature was carried out. RESULTS: The mean Constant shoulder score was 81.5, excellent functional outcomes in 24/38 patients. All the fractures healed in an average time of 3.7 months. Five patients underwent additional operations, complications included hardware penetration into the joint (n = 2), backed out screw (n = 1), shoulder impingement due to protrusion of the nail (n = 2) and superficial infection (n = 1). The literature review showed 530 patients affected by proximal humeral fracture and treated with intramedullary nail with mean age of 65 years, mean follow-up of 22.2 months and a Constant shoulder score of 72.9 points; the major complications reported were backing out of the screws, shoulder impingement and joint protrusion of the screws. CONCLUSIONS: Antegrade short locked intramedullary nail allows stable fixation, minimal soft tissue dissection, early mobilization of the shoulder and good outcomes. It is an efficacious therapeutic solution for 2- and 3-part proximal humeral fractures.

Parameterization of proximal humerus locking plate impingement with in vitro, in silico, and in vivo techniques.

BACKGROUND: Locked plating of displaced proximal humeral fractures is common, but rates of subacromial impingement remain high. This study used a multidisciplinary approach to elucidate the relationships between common surgical parameters, anatomic variability, and the likelihood of plate impingement. METHODS: The experiment was completed in 3 phases. First, a controlled in vitro experiment was conducted to simulate impingement. Second, a dynamic in silico musculoskeletal model modeled changes to implant geometry, surgical techniques, and acromial anatomy, where a collision detection algorithm was used to simulate impingement. Finally, in vivo shoulder kinematics were recorded for 9 activities of daily living. Motions that created a high likelihood of impingement were identified. RESULTS: Of simulated impingement events, 73.9% occurred when the plate was moved proximally, and 84% occurred when acromial tilt was 20° or 25°. Simulations of impingement occurred at cross-body adduction angles between 10° and 50°. Impingement occurred at an average of 162.0° ± 14.8° abduction with 10 mm distal plate placement, whereas the average was 72.1° ± 11.4° with 10 mm proximal placement. A patient may encounter these shoulder angles when performing activities such as combing one's hair, lifting an object overhead, and reaching behind one's head. DISCUSSION AND CONCLUSION: Proximal implant placement and decreases in acromial tilt play major roles in the likelihood of impingement, whereas plate thickness and humeral head center of rotation should also be considered. Careful preoperative planning that includes these factors could help guide operative decision making and improve clinical outcomes.

Three-dimensional scapular kinematics, shoulder outcome measures and quality of life following treatment for breast cancer - A case control study.

BACKGROUND: There are no conclusive results concerning changes in scapular kinematics associated with upper limb dysfunctions after breast cancer surgery. OBJECTIVE: To compare the three-dimensional (3-D) scapular kinematics during elevation of the arm between women after breast cancer surgery and controls. Shoulder range of motion (ROM), muscle strength, pain intensity, upper limb function, and quality of life were also assessed. METHODS: Forty-two women were assigned to two groups (surgery group, n = 21; control group, n = 21). 3-D scapular kinematics was collected during elevation of the arm in the scapular plane. ROM was assessed using a digital inclinometer, muscle strength using a manual dynamometer, pain with the Visual Analogue Scale (VAS), upper limb function with the Disabilities of the Arm, Shoulder and Hand (DASH) questionnaire and quality of life with the 36-item Short-Form Health Survey (SF36). RESULTS: The surgery group presented decreased scapular upward rotation at 120° of arm elevation in the scapular plane (p < .05; d = -0.88), decreased shoulder external rotation ROM and strength of shoulder abduction and external rotation when the affected side was compared to the non-affected side and control group. Moreover, the surgery group also reported higher pain, increased upper limb disability and poorer quality of life compared with healthy controls. CONCLUSION: Scapular upward rotation seems to be decreased at 120° of arm elevation in women following breast cancer surgery. In addition, shoulder external rotation ROM, abduction strength, external rotation strength, function, and quality of life are also impaired in these women. They also experienced pain during the studied movements.

Frozen shoulder or shoulder stiffness from Parkinson disease?

PURPOSE: To understand the role of camptocormia (increased kyphosis) and postural alteration in Parkinson's disease in the development of shoulder pathology, with a special concern for adhesive capsulitis and shoulder stiffness. METHODS: A preliminary online search was carried out, with combination of keywords including "Parkinson," "Shoulder stiffness," "Frozen shoulder," "Adhesive capsulitis," "Postural alteration," "Camptocormia". The retrieved papers were screened by title and abstract and those considered relevant to the aim of the review were read in full text and included. Relevant information were extracted and reported into text. RESULTS: Due to a severe impairment of posture, patients affected by PD show an increased thoracic kyphosis (camptocormia) and decreased mobility of the trunk that can yield a humeroacromial impingement syndrome and capsulitis, resulting in inflammation of the bursa, shoulder pain and reduction of movement. Furthermore, kinematic of the shoulder is allowed by the combined movement of the humerus, the scapula, the clavicle, the thoracic wall and thoracic spine. The thoracic spine and wall mobility are severely impaired in the parkinsonian patient, thus limiting the shoulder motion. CONCLUSION: The postural alteration observed in PD is the primum movens for shoulder pathology, since anterior tilt of the scapula, which occurs with the increment of thoracic kyphosis, yields to a subacromial impingement. A closed loop is then created, as the rigidity of the shoulder causes further alteration in the posture, which worsens the impingement syndrome and so on.

A Systematic Review and Meta-analysis of Functional Shoulder Impairment After Latissimus Dorsi Breast Reconstruction.

PURPOSE: The latissimus dorsi flap (LDF) is a very reliable flap and may be used for a multitude of reconstructive purposes. It is widely used for breast reconstruction when performed. It has few complications, except for a possible impact on shoulder function. The aims of this study were to evaluate the validity of the literature by investigating the level of evidence and to perform a meta-analysis. METHODS: A systematic literature search was conducted using the databases PubMed, Scopus, and Web of Science. Predictor variables were shoulder function after breast reconstruction with the LDF. Articles were chosen according to 4 different outcomes: shoulder range of motion (ROM), shoulder strength, DASH score, and subjective evaluation. RESULTS: Twenty-six articles were found, including 1045 patients: 8 level II, 16 level III, 1 level IV, and 1 level V articles. The meta-analysis showed that both ROMs for flexion and abduction are significantly impaired at less than or at 3 months of follow-up. CONCLUSIONS: There are several influencing factors, such as age, smoking, obesity, radiotherapy, and physiotherapy. Moreover, the impact on shoulder function seemed influenced by the type of thoracodorsal vessel-based flap. From the level of evidence analysis, there is a tendency that the LDF transfer does affect shoulder function. This limitation seems to be minimal, and few patients experience a major impact on shoulder function. However, the existing literature on total shoulder impairment after breast reconstruction with LDF is insufficient to draw any final conclusion. There is a need for future studies and current articles that suggest that the initial measurement should be performed preoperatively (preferably at the time of diagnosis or initial biopsy) and follow-ups with measurements at 6, 12, and 24 months (long-term effect) after surgery. We recommend measurements of both operated and nonoperated sides. Each measurement should be accompanied by a history with special emphasis on shoulder function. The methods of measuring outcomes of recommendation are DASH score, ROM with use of a goniometer preferably by a physiotherapist or a health care professional trained by a physiotherapist, and strength measured by, for example, a handheld dynamometer.

A new method for measurement of the size of subacromial spurs of the shoulder by cassette tilt view.

OBJECTIVE: Subacromial impingement syndrome is one of the most common causes of pain in the shoulder. To this date, there is no specific radiographic view that can be used to evaluate the size of a subacromial spur. This study aims to examine a cassette tilt view can be used to evaluate the size of a subacromial spur. METHODS: A cross-sectional study was conducted between the time period of January 1, 2016, and December 31, 2016. Forty-three consecutive patients that had planned treatment of arthroscopic subacromial decompression (SAD) participated in this study. Rockwood view and cassette tilt view (caudal tilt 30  with beam and cassette) X-rays were done in all these patients. The measurements of the spur sizes were calculated from both views and were compared to the spur sizes measured intraoperatively. RESULT: The size of the spurs from intraoperative measurement was not significantly different from the spur size measured using the cassette tilt view with a mean difference of 0.54 (95% confidence interval (CI): - 0.58, 1.65), but the intraoperative measurement was significantly different from the Rockwood view spur measurement, with a mean difference of 2.84 (95% CI: 1.56, 4.11). Average proportions of the size of the spur from the cassette tilt and Rockwood view compared to that from intraoperative measurements were 1.09 and 1.55, respectively. CONCLUSION: The cassette tilt view is a simple method of measurement of the size of subacromial spurs, with good inter- and intra-observer reliabilities and good validity. This can be useful clinically when setting the patient position and portals to evaluate the size of the spur when planning SAD. LEVEL OF EVIDENCE: This is level III.

Scapular Notching After Reverse Total Shoulder Arthroplasty: Prediction Using Patient-Specific Osseous Anatomy, Implant Location, and Shoulder Motion.

BACKGROUND: Scapular notching is frequently observed following reverse total shoulder arthroplasty (rTSA), although the etiology is not well understood. METHODS: Twenty-nine patients with preoperative computed tomography (CT) scans who underwent rTSA with a Grammont design were evaluated after a minimum of 2 years of follow-up with video motion analysis (VMA), postoperative three-dimensional (3D) CT, and standard radiographs. The glenohumeral range of motion demonstrated by the VMA and the postoperative implant location on the CT were used in custom simulation software to determine areas of osseous impingement between the humeral implant and the scapula and their relationship to scapular notching on postoperative CT. Patients with and without notching were compared with one another by univariable and multivariable analyses to determine factors associated with notching. RESULTS: Seventeen patients (59%) had scapular notching, which was along the posteroinferior aspect of the scapular neck in all of them and along the anteroinferior aspect of the neck in 3 of them. Osseous impingement occurred in external rotation with the arm at the side in 16 of the 17 patients, in internal rotation with the arm at the side in 3, and in adduction in 12. The remaining 12 patients did not have notching or osseous impingement. Placing the glenosphere in a position that was more inferior (by a mean of 3.4 ± 2.3 mm) or lateral (by a mean of 6.2 ± 1.4 mm) would have avoided most impingement in the patients' given range of motion. Notching was associated with glenosphere placement that was insufficiently inferior (mean inferior translation, -0.3 ± 3.4 mm in the notching group versus 3.0 ± 2.9 mm in the no-notching group; p = 0.01) or posterior (mean, -0.3 ± 3.5 mm versus 4.2 ± 2.2 mm; p < 0.001). Two-variable models showed inferior and posterior (area under the curve [AUC], 0.887; p < 0.001), inferior and lateral (AUC, 0.892; p < 0.001), and posterior and lateral (AUC, 0.892; p < 0.001) glenosphere positions to be significant predictors of the ability to avoid scapular notching. CONCLUSIONS: Osseous impingement identified using patients' actual postoperative range of motion and implant position matched the location of scapular notching seen radiographically. Inferior, lateral, and posterior glenosphere positions are all important factors in the ability to avoid notching. Only small changes in implant position were needed to avoid impingement, suggesting that preoperative determination of the ideal implant position may be a helpful surgical planning tool to avoid notching when using this implant design. LEVEL OF EVIDENCE: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Management of AO type 12C humerus proximal metadiaphyseal fractures with minimally invasive plate osteosynthesis in geriatric patients.

BACKGROUND: To evaluate the treatment efficacy and complications of the lateral minimally invasive plate osteosynthesis (MIPO) method in geriatric patients with a humerus diaphyseal fracture with proximal extension. PATIENTS AND METHODS: The study included a total of 21 patients (18 females, 3 males; mean age 74±6.3 years, range 65-89 years) who underwent surgery with the lateral MIPO technique for a humerus diaphyseal fracture with proximal extension during the period January 2011 to December 2016. None of the patients had additional injuries and all completed regular follow-up. According to the Arbeitsgemeinschaft für Osteosynthesefragen/Association for the Study of Internal Fixation classification system, the fractures were evaluated as 12C1 in 17 cases and 12C3 in 4 cases. All patients were evaluated radiologically and functionally at 6 months and 1 year. In the follow-up evaluations, the Constant-Murley score and the Quick Disabilities of the Arm, Shoulder, and Hand (Q-DASH) score were used. RESULTS: No non-union, avascular necrosis or infection was seen in any patient. The mean time to union was 15.7 weeks. Impingement syndrome was seen in 2 patients and radial nerve palsy in 2 patients. The mean Constant-Murley score was 70.6±10.2 at 6 months and 84±7.6 at the end of 1 year. The mean Q-DASH score was 38.6±15.1 at 6 months and 21.9±13.1 at the end of 1 year. The increase in the Constant-Murley scores from 6 months to 1 year was statistically significant (p<0.0001). The decrease in the Q-DASH scores between 6 months and 1 year was determined to be statistically significant. In the 2 patients with radial nerve palsy, the functions were seen to completely recover during follow-up. No axillary nerve palsy was seen in any patient. CONCLUSION: Metadiaphyseal humerus fractures with proximal extension in the elderly can be successfully treated with the lateral MIPO technique. When applied correctly, it is a method with high rates of union and low rates of complications.

Do subscapularis tears really result in superior humeral migration?

OBJECTIVES: The aim of this study was to analyse the effect of subscapularis tear on superior humeral excursion (SHE) and acromiohumeral distance (AHD). The hypothesis was that subscapularis tears do not result in superior humeral excursion. METHODS: Patients who underwent shoulder arthroscopy between August of 2011 and 2015 were reevaluated. Those with isolated Bankart lesion were used as control group and included in the Group 1, isolated full-thickness supraspinatus tear in the Group 2, isolated subscapularis tear in the Group 3, and combined subscapularis and supraspinatus tear in the Group 4. The mean SHE and AHD measurements on magnetic resonance imaging of these groups were compared to reveal any difference in superior humeral migration (SHM). RESULTS: There were 30 patients in each group. The mean age of Group 1 (26.44 ± 8.34) was younger than the other 3 groups. The mean AHD and SHE were higher in Group 1 and 3 (Mean AHD: 12.89 ± 2.24 and 12.28 ± 1.9, respectively. Mean SHE: -3.2 ± 0.99 and -2.78 ± 0.64, respectively) than Group 2 and 4 (Mean AHD: 6.2 ± 1.78 and 6.16 ± 1.52, respectively. Mean SHE: 0.72 ± 0.65 and 1.24 ± 0.63, respectively). The AHD and SHE were strongly correlated with each other (Pearson correlation coefficient = 0.184). The inter-observer and intra-observer correlation of the measurements of SHE on MRI were excellent with intraclass correlation coefficient of 0.95 and 0.94, respectively. CONCLUSION: Subscapularis tears do not lead to SHM and subacromial impingement. However, superior rotator cuff tears can still lead to SHM and subacromial impingement even when subscapularis tendon is intact. LEVEL OF EVIDENCE: Level III, diagnostic study.

Three-dimensional scapular dyskinesis in hook-plated acromioclavicular dislocation including hook motion.

BACKGROUND: The purpose of this study is to analyze the 3-dimensional scapular dyskinesis and the kinematics of a hook plate relative to the acromion after hook-plated acromioclavicular dislocation in vivo. Reported complications of acromioclavicular reduction using a hook plate include subacromial erosion and impingement. However, there are few reports of the 3-dimensional kinematics of the hook and scapula after the aforementioned surgical procedure. METHODS: We studied 15 cases of acromioclavicular dislocation treated with a hook plate and 15 contralateral normal shoulders using computed tomography in the neutral and full forward flexion positions. Three-dimensional motion of the scapula relative to the thorax during arm elevation was analyzed using a computer simulation program. We also measured the distance from the tip of the hook plate to the greater tuberosity, as well as the angular motion of the plate tip in the subacromial space. RESULTS: Decreased posterior tilting (22° ± 10° vs 31° ± 8°) in the sagittal plane and increased external rotation (19° ± 9° vs 7° ± 5°) in the axial plane were evident in the affected shoulders. The mean values of translation of the hook plate and angular motion against the acromion were 4.0 ± 1.6 mm and 15° ± 8°, respectively. The minimum value of the distance from the hook plate to the humeral head tuberosity was 6.9 mm during arm elevation. CONCLUSIONS: Acromioclavicular reduction using a hook plate may cause scapular dyskinesis. Translational and angular motion of the hook plate against the acromion could lead to subacromial erosion. However, the hook does not seem to impinge directly on the humeral head.

Lower shoulder abduction during throwing motion may cause forceful internal impingement and decreased anterior stability.

BACKGROUND: Internal impingement and decreased anterior stability, which result from shoulder capsular loosening, are common shoulder pathologies in throwing athletes. The purpose of this study was to assess the effect of shoulder abduction angle on shoulder internal impingement and anterior shoulder stability during the simulated throwing motion. METHODS: Eight cadaveric shoulders were tested by simulating the late-cocking and acceleration phases of the throwing motion for intact and thrower's shoulder conditions. The maximal glenohumeral external rotation, anterior translation, location of the rotator cuff insertion with respect to the glenoid, length and site of internal impingement, and glenohumeral contact pressure were measured. All data were compared between shoulder abduction angles of 80°, 90°, and 100°. RESULTS: Decreasing shoulder abduction in the simulated late-cocking phase shifted the humeral head posteriorly (P < .03) and superiorly (P < .001), decreasing the total internal impingement area between the greater tuberosity and glenoid (P = .04) and increasing the glenohumeral contact pressure during internal impingement (P = .02). In the simulated acceleration phase, anterior glenohumeral translation significantly increased as the shoulder abduction angle decreased (P < .001). CONCLUSION: Decreasing shoulder abduction significantly increased the contact pressure during internal impingement in the simulated late-cocking phase of the throwing motion. During the simulated acceleration phase of the throwing motion, anterior glenohumeral translation significantly increased as shoulder abduction decreased.