A. Van Tongel

A cadaveric study of the structural anatomy of the sternoclavicular joint.

Pathologies of the sternoclavicular (SC) joint are infrequent and effective management is often hindered by a limited understanding of the anatomy. In this study, we did macroscopic evaluations of the ligaments, the intra‐articular disc, and the articulating surfaces of 25 SC joints. After removal of the joint capsule, the articulating surfaces of the sternal end of clavicle and the sternum were evaluated and the intra‐articular disc was macroscopically examined. The anterior SC ligament covered the intra‐articular disc, which divided the joint into a clavicular and a sternal part. A thin capsule, relatively lateral and medial from the anterior SC ligament, covered the two intra‐articular parts. This means that the anterior SC ligament can be used as a landmark to enter into clavicular or sternal part of the SC joint. Posteriorly, there was a thick capsule without soft‐spot or clear posterior SC ligament. Only the antero‐inferior surface of the sternal end of every clavicle was covered by cartilage. Of the intra‐articular discs 56% were incomplete. All of these incomplete discs displayed a central hole with signs of degeneration and fraying. This was associated with increased cartilage degeneration at the clavicular side. By experimental design (past and present), it would seem reasonable to assume that the incomplete types are caused by degeneration and are not developmental. Clin. Anat. 25:903–910, 2012.

MEASURING SHOULDER EXTERNAL AND INTERNAL ROTATION STRENGTH WITH A HAND-HELD DYNAMOMETER, AND RANGE OF MOTION USING A GONIOMETER AND A DIGITAL INCLINOMETER: COMPREHENSIVE INTRA- AND INTER RATER RELIABILITY STUDY OF SEVERAL TESTING PROTOCOLS

Background Shoulder range of motion (ROM) and strength measurements are imperative in the clinical assessment of the overhead athlete in the prevention and rehabilitation of sports related shoulder injuries. The method and type of assessment varies among clinicians and institutions. Until present, no comprehensive study ever examined reliability of a variety of procedures based on different testing equipment, and specific patient or shoulder position. Objective To establish absolute and relative reliability for several procedures measuring the rotational shoulder ROM and strength into internal (IR) and external (ER) rotation strength. Design Controlled laboratory study. Participants 30 healthy subjects (15 male, 15 female) with a mean age of 22.1 (±1.4) years. Risk factor assessment Subjects were examined by 2 examiners measuring ROM with a goniometer and inclinometer, and isometric strength with a Hand-Held-Dynamometer (HHD) respectively, in different patients positions, and shoulders positions. Relative reliability was determined by Intra-Class-Correlation coefficients (ICC). Absolute reliability was quantified by Standard-Error-of-Measurement (SEM) and Minimal-Detectable-Change (MDC). Systematic differences across trials or between testers, as well as differences among similar measurements under different testing circumstances were analyzed with dependent t-tests or ANOVA Repeated Measures (in case of 2 or more than 2 conditions respectively). Main outcome measurements Range of motion (in degrees) and isometric muscle strength (in Newton). Results Good to excellent intra- and intertester reliability was established for IR and ER ROM and isometric strength measurements, regardless of patient or shoulder position or equipment used (ICC 0.85-0.99). No systematic differences were found across trials or between testers. However patients position, as well as equipment resulted in different outcome measures. Conclusions All procedures examined showed acceptable reliability for clinical use. However, patient position and equipment might influence the results. For sport specific measurements, ROM and strength should be measured in positions, resembling the throwing position.

Improving the surface properties of an UHMWPE shoulder implant with an atmospheric pressure plasma jet

Insufficient glenoid fixation is one of the main reasons for failure in total shoulder arthroplasty. This is predominantly caused by the inert nature of the ultra-high molecular weight polyethylene (UHMWPE) used in the glenoid component of the implant, which makes it difficult to adhesively bind to bone cement or bone. Previous studies have shown that this adhesion can be ameliorated by changing the surface chemistry using plasma technology. An atmospheric pressure plasma jet is used to treat UHMWPE substrates and to modify their surface chemistry. The modifications are investigated using several surface analysis techniques. The adhesion with bone cement is assessed using pull-out tests while osteoblast adhesion and proliferation is also tested making use of several cell viability assays. Additionally, the treated samples are put in simulated body fluid and the resulting calcium phosphate (CaP) deposition is evaluated as a measure of the in vitro bioactivity of the samples. The results show that the plasma modifications result in incorporation of oxygen in the surface, which leads to a significant improved adhesion to bone cement, an enhanced osteoblast proliferation and a more pronounced CaP deposition. The plasma-treated surfaces are therefore promising to act as a shoulder implant.

Introduction of the Angle of Shoulder Slope in a South African Population

Background: The angle of shoulder slope has been reported in accordance with the specific occupational activities of the aviation and textile industries. However, as no accurate definition nor standardised anatomical landmarks exist within the medical field, this study aimed to devise an appropriate definition with preplaced reference landmarks. In addition, the vertebral level of the acromial tip was also determined. Methods: The sample series comprised 260 posterior radiographs of the shoulder, of which 127 were males and 133 females. The ethnic distribution included ten black, 13 coloured, 49 Indian and 188 white individuals. In accordance with the trapezial line, the angle of shoulder slope was defined and measured as the angle between the line from the spinous process of C7 to the acromial tip and the line from the acromial tip directly across to the median plane of the vertebral column. Results: The standard mean angle of shoulder slope was approximately 13.56±3.70o. Left and right sides appeared to have mean angles of 13.81±3.41o and 13.33±3.95o, respectively. Mean angular values were also calculated in accordance with the demographic representation – sex: male 13.64±3.71o, female 13.48±3.71o; ethnic groups: black: 13.81±3.81o, coloured: 12.18±3.82o, Indian: 12.97±3.09o, white: 13.64±3.96o. Although the acromial tip was commonly aligned to the level of the spinous process of T3, the incidence of the vertebral level of the acromion was categorised into seven groups, viz. i) intervertebral disc between T1 and T2; ii) intervertebral disc between T2 and T3; iii) intervertebral disc between T3 and T4; iv) spinous process of T1; v) spinous process of T2; vi) spinous process of T3; vii) spinous process of T4. Conclusion: Since a statistically significant P value was recorded for the comparison between the angle of shoulder slope and the acromial vertebral level, it was postulated that the magnitude of the angle may determine the acromial vertebral level. As the present study incorporated standard osteological landmarks into the definition and calculation of the angle of shoulder slope, it may provide reference data regarding the position of the acromion which may be indicative of shoulder asymmetry and distorted shoulder setting. Level of evidence: Level 3

Physical Examination of the Elbow

The evaluation of elbow pain in the athlete can be challenging because of the complexity of the joint and its central location in the upper extremity. Although the elbow is not a weight bearing joint, it is subjected to significant loads, especially in overhead and throwing athletes.

The history of shoulder arthroplasty

Abstract: Shoulder arthroplasty is currently an established treatment for any type of osteoarthritis. It can provide reliable pain relief and, if biomechanical and anatomical considerations are taken into account pre- and postoperatively, it can provide an improved to almost normal function of the shoulder. These results last on the longer term and provide a relevan improvement of the quality of life. Depending on the indication an anatomical or a reverse polarity shoulder arthroplasty can be indicated. In general, the anatomical prosthesis needs a normal rotator cuff function whereas the reversed prosthesis only needs a well-functioning deltoid. This chapter discusses the biomechanical specificities and indications of each type of shoulder prosthesis.