Ipsilateral shoulder and elbow replacements: on the risk of periprosthetic fracture

Background. Ipsilateral shoulder and elbow replacements may leave only a short segment of bone bridging the two implants in the humerus. The potential for high stress concentrations as a result of this geometry has been a concern with regard to periprosthetic fracture, especially with osteoporotic bone. The study aims to determine the optimum length of the bone-bridge between shoulder and elbow humeral implants, and to assess the effect of filling the canal with cement.

Methods. A three-dimensional finite element model was used to compare the stresses between a humerus with a solitary prosthesis and a humerus with both proximal and distal cemented prostheses. The length of the bone-bridge and the effect of filling the canal with cement were studied under bending and torsion.

Findings. Gradual load transfer from prosthesis to bone was observed for all cases, and no stress concentration was evident. The length of the bone-bridge had no deleterious effect on stresses in the humerus, and filling the canal with cement did not appreciably decrease the loads carried by the humerus.

Interpretation. The length of the bone-bridge between stem tips has little effect on the resultant stresses in the humerus. Filling the canal with cement adds little benefit to the structural integrity of the humerus. Ipsilateral shoulder and elbow prostheses may be considered independent of one another in terms of risk of periprosthetic fracture.     

Isokinetic assessment of shoulder complex strength in adolescent elite synchronized swimmers

Children and adolescent participation in sport has increased in recent years. Synchronized swimming requires correct muscle balance in the shoulder complex. The purpose of this study was to establish isokinetic strength profiles and peak torque ratios of shoulder internal and external rotator muscles in a female high-level synchronized swimming team. Twenty-six adolescent female high-level synchronized swimmers, aged 12–14, participated in this study. Maximal bilateral shoulder concentric external and internal rotation force was measured at 60°/s (5 repetitions) and 180°/s (15 repetitions). The isokinetic concentric strength generated by the internal rotator muscles was significantly higher (p?<?0.05) than by the external rotators in both limbs and at both velocities. Significant bilateral differences in the external rotation (ER):internal rotation (IR) strength ratio were noted at 60°/s. Isokinetic assessment is essential in sports medicine, since it is the only test capable of diagnosing any shoulder strength deficit.     

Measurement properties of objective methods to assess shoulder muscle strength (a systematic review protocol)

Introduction: Shoulder disorders cause significant impaired function and health-related quality of life. Treatment consists of either conservative or surgical treatment, and results in substantial health care utilization. Strengthening exercises of the rotator cuff muscles are often included in physiotherapy treatment of patients with shoulder disorders. Valid and reliable measurement methods to assess shoulder muscle strength are important to analyse the efficacy of treatment in both clinical practice and research. There is a need for an up to date systematic review that summarize the evidence of measurement properties of objective measurements of isometric and isokinetic shoulder muscle strength in individuals with and without shoulder symptoms.

Aim: The aim of this review is to investigate measurement properties of objective methods to assess shoulder muscle strength.

Methods: The following databases; Cochrane Central Register of Controlled Trials (CENTRAL), Pubmed, EMBASE, and PEDro will be searched for relevant studies reporting the assessment of measurement properties of objective methods used to assess shoulder muscle strength. The methodological quality will be assessed with the Consensus-based Standards for the selection of health Measurement Instruments (COSMIN) checklist. The overall evidence of the measurement properties of the included instruments will be summarized in a best evidence synthesis.     

Reliability of physical examination tests used in the assessment of patients with shoulder problems: a systematic review

Background

Shoulder pain is a common clinical problem, and numerous tests are used to diagnose structural pathology.

Objectives

To systematically review the reliability of physical examination procedures used in the clinical examination of patients with shoulder pain.

Data sources

MEDLINE, PEDro, AMED, PsychInfo, Cochrane Library (2009) and CINAHL were searched from the earliest record on the database to June 2009.

Study eligibility criteria

Reliability studies that included any patients with shoulder pain were analysed for their quality and reliability results.

Study appraisal and synthesis methods

Pre-established criteria were used to judge the quality of the studies (high quality >60% methods score) and satisfactory levels of reliability (kappa or intraclass correlation coefficient ≥0.85, sensitivity analysis 0.70). A qualitative synthesis was performed based on levels of evidence.

Results

Thirty-six studies were included with a mean methods score of 57%. Seventeen studies were deemed to be of high quality; high-quality studies were less likely to meet the pre-agreed level of reliability. The majority of studies indicated poor reliability for all procedures investigated.

Limitations

Overall, the evidence regarding reliability was contradictory.

Conclusions and implications

There is no consistent evidence that any examination procedure used in shoulder assessments has acceptable levels of reliability. Alternate methods of classification which are reliable should be used to classify patients with shoulder problems.     

Reduced elbow mobility affects the flexion or extension domain in activities of daily living

Background

Rehabilitation of patients with joint affecting diseases makes an appeal to available compensating motions. Objective information about compensatory motions is required for clinical decision-making. Our objective was to quantify resulting shoulder and arm motions from limited elbow mobility during activities of daily living in healthy controls and patients.

Methods

Ten hemophilia patients with reduced elbow motion and ten controls volunteered in a kinematic motion analysis of thorax, shoulder, arm and wrist during 5 experimental activities of daily living. In controls, the elbow range of motion was limited by an elbow brace with variable flexion and extension stops. The elbow angle of patients was not intervened. Outcome variables were minimal required elbow range of motion for successful activity of daily living completion and concurring compensatory motions.

Findings

An elbow flexion and extension domain was identified separated by a 97° to 110° interval in which none of the observed tasks could be fulfilled. A minimal average elbow flexion angle of 86° and an additional range of motion of 36° were required to finish all tasks successfully. Predominant significant compensatory motion was found in the glenohumeral joint and wrist.

Interpretation

Two functional elbow flexion domains exist, separated by a transition domain of 36°. Treatment should be focussed to bridge both domains. Limiting treatments, e.g. arthrodesis of the elbow joint within this transition range, especially in a cosmetic 90°, leads to severe disability. Limited joint range of motion requires increased compensatory motions in other joints.     

Comparison of portable handheld versus fixed isokinetic dynamometers in measuring strength of the wrist and forearm

Purpose: The purpose of this study was to test the concurrent validity of using hydraulic dynamometers in comparison to the gold standard isokinetic dynamometers in measuring wrist and forearm strength. Materials and methods: Healthy adults between the ages of 18–65 participated, including 24 participants, 8 men and 16 women. The examiner used a handheld dynamometer, forearm/wrist dynamometer, and an isokinetic dynamometer to measure force/torque production in forearm rotation and wrist flexion/extension using a standardized protocol of two handle types for each motion. Sequence of testing was randomized. The data were analyzed using Pearson correlation coefficients and paired t-tests. Results: When matched for handle type, three of the four correlations between the strength measurements taken with the different dynamometers were moderate to high with Pearson product moment coefficients ranging from 0.72 to 0.96; the screwdriver handle demonstrated less than acceptable correlation (r = 0.45, 0.67 for wrist flexion and extension, respectively). There were significant differences in most of the force/torque values obtained by different handle types for wrist and forearm motions. Discussion and conclusions: Overall, the dynamometers demonstrated acceptable correlations supporting concurrent validity for measuring forearm and wrist strength, except with the screwdriver handle. However, different tools, positions, and handle interfaces provided different absolute values, therefore the tools cannot be used interchangeably. It is recommended that repeated measurements to monitor patient progress are taken with the same tool and handle type.     

Ultrasound assessment of elbow enthesitis in patients with seronegative arthropathies

Background

Enthesopathy is an evolving area for applied clinical research. MRI is the gold standard in the diagnosis of elbow joint pathology, but recent reports indicate that ultrasound imaging is more sensitive and accurate than MRI in detecting enthesopathy of the heels and knees. Too many patients are under-diagnosed and/or misdiagnosed because the early pathological changes of enthesitis in the different types of seronegative arthropathies are not detected.

Objectives

This study was undertaken to describe the ultrasound features of elbow enthesitis in patients with seronegative arthropathies.

Methods

We studied 38 diseased elbows in 38 patients with spondyloarthropathies (26 men and 12 women, mean age 32 years). All had elbow enthesopathy without typical conventional radiographic findings. Patients with histories of degenerative changes and/or local steroid injections were excluded. An HDI 3000 ATL ultrasound machine was used with a 5–12 MHz linear transducer to examine the affected elbow joints. The elbows of 10 normal healthy individuals were examined as normal controls. The patients were examined in the supine position with the elbow flexed 30°–50°. Longitudinal and transverse scans were obtained of the radiohumeral joint, the ulnahumeral joint, and the olecranon fossa. Two independent observers unaware of the clinical diagnosis read the ultrasound images and assessed the collateral ligaments, intratendinous echogenicity, tendon calcification, tendon thickness, presence of fluid, synovial proliferation, and bony changes. The reliability of the sonographic images was assessed by review of video recordings of the ultrasound examinations.

Results

Ultrasound revealed loss of the fibrillar echopattern (100 %), lack of a homogenous pattern with loss of the tightly packed echogenic dots (100 %), peritendinous edema with flaring of the tendon margins (84.2 %), irregular fusiform tendon thickening (100 %), and hyperechoic intratendinous lesions with ill-defined focal defects (18.4 %). Ultrasound also detected intratendinous calcifications of both the common extensor and common flexor tendons (52.6 %). Bony erosions were seen at the tendon insertions into the lateral epicondyles (13.15 %).

Conclusion

Ultrasonographic features of elbow enthesitis differed from those described in knee and heel enthesitis. Ultrasound clearly showed early signs of tendon calcification, tendon edema, peritendinitis, and bony entheseal erosions. However, in elbow enthesitis the early bone erosion was associated with bone marrow edema, and the common extensor tendon was diffusely thickened. Ultrasound is a reliable, reproducible bedside imaging procedure. It improves the documentation of disease activity, progression, and treatment responses in patients with spondyloarthropathies. We recommend its use for the diagnosis and post-treatment follow-up of patients with enthesitis and seronegative spondyloarthropathies.     

Ranges of active joint motion for the shoulder,elbow, and wrist in healthy adults

Purpose: The aim of this study was to show highly reliable normal values and three-dimensional characteristics for final range of motion during active movements of the upper extremity joints, and to develop a database from healthy participants, with the advantage of this database lying in the methods of defining shoulder axial rotation angle and of compensating for soft tissue artifacts. Methods: We used an electromagnetic tracking system (FASTRAK) to measure three-dimensional motions of the shoulder (thoracohumeral), elbow/forearm, and wrist in 20 healthy adults (age range: 18–34 years) during active joint motion tasks of the upper extremity. Results: Joint angles of the upper extremity at the final position of joint motion tasks were determined. Highly reliable data for shoulder axial rotation angle were obtained, using a new definition of joint angle and regression analysis to compensate for estimation errors. Conclusions: These results should be useful in setting goals for the treatment of upper extremity joint functions in the fields of rehabilitation, orthopedics, and sports medicine.

Implications for Rehabilitation

• Complex joint motions that occur naturally (unconsciously) about some axes should be taken into account in interventions for range of joint motion (ROM).

• The data obtained through this study simultaneously indicating multiple interrelated angles can be used as reference values for maximum active ROM.

• ROM in the directions of motion involved in the various tasks (for example, elevation angle during shoulder flexion) may have a role to play in evaluating and setting goals for patients with impaired ROM of the arm joints.

     

Ultrasound of the elbow: Examination techniques and US appearance of the normal and pathologic joint

Ultrasound studies are frequently requested for the work-up of patients with local elbow pain, which is generally caused by overuse syndromes, trauma, inflammatory diseases, or neuropathies. The technique used to examine this joint will vary to some extent depending on the precise location of the pain and other clinical findings. The aim of this article is to describe the standard technique used for elbow ultrasound, the normal anatomy of the joint, and the appearance on ultrasound of normal elbow anatomy and the alterations associated with some of the more common disorders affecting this joint.     

偏瘫肩半脱位康复评定与放射学测量研究

目的：比较康复评定与放射学测量在偏瘫肩半脱位评定中的应用价值。方法：偏瘫肩半脱位３７例，平均年龄６０．１±１１．５岁，分为低张组和高张组。用Ｆｕｇｌ－Ｍｅｙｅｒ和Ｂｒｕｎｎｓｔｒｕｍ量表评定患侧上肢功能，测量双侧肩峰下间隙，肩峰肱骨外上髁距，摄双肩正位和后斜位片，用ｔ检验和Ｓｐｅａｒｍａｎ相关性检验。结果：两组患者疼痛发生率、Ｂｒｕｎｎｓｔｒｕｍ分期、双侧肩峰下间隙、肩峰外上髁距差异有非常显著性（Ｐ＜０．０１）；放射学测量双侧肱骨头的水平和垂直移位、肱骨绝对外展角差异有显著性（Ｐ＜０．０５）；肌张力与肩峰下间隙呈负相关，简易测量和放射学测量方法明显相关（ｒ＝０．３３６～０．３６４，Ｐ＜０．０５）。结论：触诊法、简易测量和放射学检查均可用于偏瘫肩半脱位的评定，其中肩峰肱骨外上髁距具有定性和定量双重作用，且方法简单，值得在康复评定中应用。     

A finite element model of the shoulder: application to the comparison of normal and osteoarthritic joints

Objective. The objective of the present study was to develop a numerical model of the shoulder able to quantify the influence of the shape of the humeral head on the stress distribution in the scapula. The subsequent objective was to apply the model to the comparison of the biomechanics of a normal shoulder (free of pathologies) and an osteoarthritic shoulder presenting primary degenerative disease that changes its bone shape.

Design. Since the stability of the glenohumeral joint is mainly provided by soft tissues, the model includes the major rotator cuff muscles in addition to the bones.

Background. No existing numerical model of the shoulder is able to determine the modification of the stress distribution in the scapula due to a change of the shape of the humeral head or to a modification of the glenoid contact shape and orientation.

Methods. The finite element method was used. The model includes the three-dimensional computed tomography-reconstructed bone geometry and three-dimensional rotator cuff muscles. Large sliding contacts between the reconstructed muscles and the bone surfaces, which provide the joint stability, were considered. A non-homogenous constitutive law was used for the bone as well as non-linear hyperelastic laws for the muscles and for the cartilage. Muscles were considered as passive structures. Internal and external rotations of the shoulders were achieved by a displacement of the muscle active during the specific rotation (subscapularis for internal and infrapinatus for external rotation).

Results. The numerical model proposed is able to describe the biomechanics of the shoulder during rotations. The comparison of normal vs. osteoarthritic joints showed a posterior subluxation of the humeral head during external rotation for the osteoarthritic shoulder but no subluxation for the normal shoulder. This leads to important von Mises stress in the posterior part of the glenoid region of the pathologic shoulder while the stress distribution in the normal shoulder is fairly homogeneous.

Conclusion. This study shows that the posterior subluxation observed in clinical situations for osteoarthritic shoulders may also be cause by the altered geometry of the pathological shoulder and not only by a rigidification of the subscapularis muscle as often postulated. This result is only possible with a model including the soft tissues provided stability of the shoulder.

Relevance One possible cause of the glenoid loosening is the eccentric loading of the glenoid component due to the translation of the humeral head. The proposed model would be a useful tool for designing new shapes for a humeral head prosthesis that optimizes the glenoid loading, the bone stress around the implant, and the bone/implant micromotions in a way that limits the risks of loosening.     

Correlation between handgrip and isokinetic strength of shoulder muscles in elite sitting volleyball players

The aim of this study was to examine the relationships between isometric handgrip (HG) strength and isokinetic strength data of the glenohumeral rotator muscles. Twelve (Female = 50%) Brazilian Sitting Volleyball (SV) national team players volunteered. Measures of maximal grip strength were obtained by a HG dynamometer Jamar® and isokinetic measures of peak torque (PT) and total work (TW) during shoulder rotations movements were obtained with a Biodex isokinetic dynamometer at speed of 60°/s and 180°/s. Pearson correlation coefficients between isometric HG and isokinetic strength data ranged between 0.23 and 0.72 for the PT and between 0.3 and 0.76 for the isokinetic TW. Results presented positive relationships between HG isometric strength and isokinetic strength of external rotators of the shoulder in SV players. We can suggest that in the absence of isokinetic dynamometers, HG isometric strength measurements could be used to measure strength levels of the external rotator muscles of elite SV players’ shoulder, particularly in the TW values.     

A Comparison of Pitching Biomechanics and Sport Specialization in High School Pitchers

BackgroundThe prevalence of sport specialization in high school athletes continues to rise, particularly among baseball players. Previous research has focused on the incidence of injury among specialized and non-specialized athletes but has yet to examine the level of sport specialization and pitching biomechanics.Hypotheses/PurposeThe purpose of this study was to investigate differences in pitching volume and biomechanics between low-, moderate-, and high-level specialized baseball pitchers. It was hypothesized that high-level specialized pitchers would have the most pitching volume within the current and previous years while low-level specialized pitchers would exhibit the least amount. The second hypothesis states that kinematics and kinetics commonly associated with performance and injury risk would differ between low-, moderate-, and high-level specialized pitchers.Study DesignCase-Control StudyMethodsThirty-six high school baseball pitchers completed a custom sport specialization questionnaire before participating in a three-dimensional pitching motion analysis. Sport specialization was based off current guidelines and categorized as low-, moderate-, and high-level specialized based upon self-reported outcomes. Pitchers then threw ≈10 fastballs from a mound engineered to professional specifications. Data averaged across fastballs was used for biomechanics variables. Key pitching biomechanical and pitching volume variables were compared between low-, moderate-, and high-level specialized pitchers.ResultsHigh-level specialized pitchers were older (p = 0.003), had larger body mass (p = 0.05) and BMI (p = 0.045), and threw faster (p = 0.01) compared to low-level specialized pitchers. Pitching volume and pitching biomechanics were similar across groups.ConclusionsPitching biomechanics were similar across groups, although high-level specialized pitchers threw with significantly higher throwing velocity compared to low-level pitchers. The low amount of pitching volume throughout the season may be responsible for the lack of additional observed differences. Further research should examine the relationship between pitching biomechanics, upper extremity strength and flexibility, and sport specialization.Level of EvidenceLevel III     

超声检查类风湿关节炎患者肩关节病变的应用价值

目的 探讨超声检查在诊断类风湿关节炎(rheumatoid arthritis,RA)患者肩关节病变中的应用价值.方法 RA患者41例,健康志愿者20例,分别应用高频超声检查双侧肩关节,并进行临床体检,观察RA患者肩关节病变的声像图表现及临床体征,比较两种检查方法的阳性率.结果 RA患者中36个肩关节有异常超声表现,主要为肱二头肌长头腱肌腱炎、滑膜炎、肩袖病变、骨侵蚀及关节腔积液;16个肩关节临床检查有阳性体征,超声检查阳性率明显高于临床体检(P=0.001).对照组仅2个肩关节可见肱二头肌长头腱腱鞘少量积液.结论 超声可以发现RA患者多数肩关节异常改变,且其敏感性高于临床体检,具有较高的临床应用价值.     

老年男性肩关节外展,内收运动功能初步评价

应用ＫｉｎＣｏｍ等速装置对老年男性肩外展、内收运动功能进行初步评价。其中对１８名正常男性肩外展／内收进行了６０°／ｓ、１８０°／ｓ角速度下的向心收缩、离心收缩测试，并在１周后对优势肩用同样方法进行再测试，以此进行可重复性研究、年龄与力量的相关性研究、正常力矩值及有关比值分析。对１２名疼痛期冻结肩患者肩外展／内收亦进行了６０°／ｓ、１８０°／ｓ角速度下向心收缩、离心收缩测试，并采用简化ＭｃＧｉｌ疼痛调查表进行疼痛调查，以分析冻结肩患者肩外展／内收力量改变情况及其与疼痛的相关性。研究表明：正常老年男性肩外展／内收测试后再测试结果无显著差异，变异系数在８％～１７％之间，即可重复性较好；正常老年男性肩外展／内收力量与年龄之间无显著相关性；正常老年男性肩外展／内收力量及有关比值与以往研究结果基本相似，但其向心收缩力量随角速度增大而增大的原因还有待于进一步研究；优势肩与非优势肩同名肌群缺失百分比为１０％～１３％。疼痛期冻结肩患者肩外展／内收力量明显降低、缺失百分比为３０％左右，且以外展为甚；无痛阈活动范围内测试方法、简化ＭｃＧｉｌ疼痛调查结果与力量相关分析结果表明这种力量显著降低并非由疼痛引起的肌肉痉挛所致。     

Safety and efficacy of arthroscopy in the setting of shoulder arthroplasty

Shoulder arthroplasty has become a reliable and reproducible method of treating a range of shoulder pathologies including fractures, osteoarthritis, and rotator cuff arthropathy. Although most patients experience favorable outcomes from shoulder arthroplasty, some patients suffer from persistent symptoms post-arthroplasty and it is these patients who present a unique diagnostic and therapeutic challenge. The role of arthroscopy in assessing and treating patients with symptomatic prosthetic joints elsewhere in the body has been established in recent literature. However, the range of pathology that can affect a prosthetic shoulder is distinct from the knee or the hip and requires careful and considered assessment if an accurate diagnosis is to be made. When used alongside other investigations in a comprehensive assessment protocol, arthroscopy can play an important role in the diagnosis and treatment of the problematic shoulder arthroplasty.     

In vitro quantitative assessment of total and bipolar shoulder arthroplasties: A biomechanical study using human cadaver shoulders

Background

Glenohumeral arthroplasty has produced results far inferior to those seen with hip and knee joint procedures. Therefore, the objective of this study was to evaluate the biomechanical parameters of the glenohumeral joint before and after total shoulder arthroplasty and bipolar hemiarthroplasty in 12 different positions simulating overhead activities.

Methods

Six matched pairs of cadaveric shoulders were used with a custom shoulder testing system to quantify the joint reactive force, contact areas, contact patterns and contact pressures in 12 different positions simulating overhead activities. The entire study was performed for the anatomic glenohumeral joint and following total shoulder arthroplasty on one side, and for the anatomic glenohumeral joint and following bipolar shoulder hemiarthroplasty on the contra-lateral side.

Findings

There was a significant increase in posterior force following total shoulder arthroplasty in two positions of horizontal adduction (P < 0.05). In positions of increased glenohumeral abduction and horizontal adduction, the contact pressures and patterns were greatly altered following both total shoulder arthroplasty and bipolar hemiarthroplasty procedures compared to the anatomic state.

Interpretation

The alterations in joint reaction force, contact pressure and contact patterns following shoulder arthroplasty suggest a possible etiology for glenoid component edge loading in patients following total shoulder arthroplasty. This edge loading may lead to a rocking phenomenon of the glenoid component and subsequent loosening.