Capsular Insertions Research Articles

Anatomy of lateral meniscus.

The anatomy of the lateral meniscus underlies the understanding of its unique biomechanics. Moreover, the knowledge of its microscopic structure, its vascularization and its ligament insertions can make us understand the rationale for its surgical treatment. It is well known as the respect of the anatomy leads to better results in reconstructive surgery. Knowing the differences in the shape and in the areas of insertion of the meniscal roots can be useful in case of reinserting a root or when performing a meniscal transplant. Learning about the capsular insertions, the anchoring ligaments and the areas of greatest mobility of the lateral meniscus is useful during meniscal repair and replacement surgery. This information can let us choose the most appropriate technique and the best device to face any kind of meniscal lesion. In this article, we will consider both the micro and the macro meniscal structure in order to be able to give a description as complete as possible of this fundamental structure. We will consider the interrelation of the meniscus with the neighboring anatomical structures with which it contributes to the biomechanical control of the joint. It is important to understand the interrelation with both anterior and posterior cruciate ligament (PCL) given that frequently a combined meniscal and ligamentous reconstruction is necessary.

Biomechanical Evaluation of Knotless and Knotted All-Suture Anchor Repair Constructs in 4 Bankart Repair Configurations

To evaluate the biomechanical performance of Bankart repair using 1.8-mm knotless all-suture anchors in comparison to 1.8-mm knotted all-suture anchors with both simple and horizontal mattress stitch configurations. Thirty fresh-frozen human cadaveric shoulders were dissected to the capsule, leaving the glenoid and humeral capsular insertions intact. A standardized anteroinferior labral tear was created and repaired using 3 anchors. A 2× 2 factorial design was implemented, with 6 matched pairs randomized between knotless and knotted anchor repairs and 6 matched pairs randomized into simple and horizontal mattress stitch configurations. In addition, 6 unpaired shoulders were used to evaluate the native capsulolabral state. First failure load, ultimate load, and stiffness were assessed. Linear mixed-effects modeling was used to compare endpoints. Digital image correlation was used to evaluate capsular strain throughout testing. Failure modes were reported qualitatively. The knotless all-suture anchor repair showed similar biomechanical strength to the knotted all-suture anchors for first failure load (coefficient, 142 N; 95% confidence interval [CI], -30 to 314 N; P= .12), ultimate load (coefficient, 11.1 N; 95% CI, -104.9 to 127.2 N; P= .847), and stiffness (coefficient, 3.4 N/mm2; 95% CI, -14.1 to 20.9 N/mm2; P= .697) when stitch configuration was held constant. No statistically significant differences were found on comparison of simple and mattress stitch configurations for first failure load (coefficient, -31 N; 95% CI, -205 to 143 N; P= .720), ultimate load (coefficient, 112 N; 95% CI, -321 to 97 N; P=.291), and stiffness (coefficient, -9.6 N/mm2; 95% CI, -27.3 to 8.1 N/mm2; P= .284) when anchor type was held constant. Specimens with knotless anchors and simple stitch techniques resulted in lower stiffness compared with the native state (P= .030). The knotless-mattress configuration resulted in significantly lower strain than the knotted-mattress (P= .037) and knotless-simple (P= .019) configurations and was the only configuration that did not result in a significant increase in strain compared with the intact specimens (P= .216). Fewer instances of suture slippage (loss of loop security) were observed with knotless anchors versus knotted anchors (11% vs 30%), and less soft-tissue failure was observed with the mattress stitch configuration versus the simple stitch configuration (36% vs 47%). Knotless and knotted all-suture anchor repairs with simple and mattress stitch configurations showed similar values of ultimate load, first failure load, and stiffness. However, the horizontal mattress stitch configuration proved to decrease capsular strain more similarly to the native state compared with the simple stitch configuration. Ultimate load and first failure load for all repairs were similar to those of the native state. Knotless all-suture anchors have a smaller diameter than solid anchors, can be inserted through curved guides, and preserve glenoid bone stock. This study presents knotless, tensionable all-suture anchor repair for labral tears that displays high biomechanical fixation strength, similar to the native capsulolabral state.

Glenohumeral instability

• Normal anatomical variants: ○ Sublabral foramen ○ Sublabral recess ○ Buford complex ○ Capsular insertions • Shoulder instability: ○ Anterior glenohumeral instability • Anteroinferior labral tear ○ Bankart lesion ○ Anterior labroligamentous periosteal sleeve avulsion lesion ○ Perthes lesion ○ Glenolabral articular disruption lesion • Extensive anterior labral tear • Anterosuperior labral tear • Glenohumeral ligament injury ○ SLAP lesion ○ Posterior glenohumeral instability ○ Posterior superior glenoid impingement MR arthrography is useful in diagnosing and characterizing the labral–ligamentous lesions resulting in glenohumeral instability. The sublabral foramen, sublabral recess and Buford complex are normal variants of the glenoid labrum, which must not be confused with true labral abnormalities. The most common type of glenohumeral instability is anteroinferior instability, characterized by avulsion of the anteroinferior labral–ligamentous complex, which is termed a Bankart lesion. Variants of the Bankart lesion, where the scapular periosteum remains intact, are the anterior labroligamentous periosteal sleeve avulsion lesion, the Perthes lesion and the glenolabral articular disruption lesion. Anterosuperior labral tears are uncommon and must be differentiated from a normal sublabral foramen. Anterior glenohumeral instability also occurs following injury to the glenohumeral ligaments, most commonly described as humeral avulsion of the inferior glenohumeral ligament lesion. The superior labral anteroposterior (SLAP) lesion is a superior labral tear that extends both anterior and posterior to the biceps tendon attachment. SLAP lesions have a complex classification but the presence and the extent of biceps tendon involvement is the most important feature. A SLAP II lesion must be distinguished from a normal sublabral recess. Patterns of injury seen in posterior instability are the reverse of those found following anterior dislocation with posterior labral tears referred to as a reverse Bankart lesion. Posterior superior glenoid impingement or internal impingement is when the posterosuperior aspect of the glenoid and the humeral head come into contact, causing injury to the interposed rotator cuff and posterosuperior labrum.

Surgically Relevant Bony and Soft Tissue Anatomy of the Proximal Femur.

Background:Hip endoscopy facilitates the treatment of extra-articular disorders of the proximal femur. Unfortunately, current knowledge of proximal femur anatomy is limited to qualitative descriptions and lacks surgically relevant landmarks.Purpose:To provide a quantitative and qualitative analysis of proximal femur anatomy in reference to surgically relevant bony landmarks.Study Design:Descriptive laboratory study.Methods:Fourteen cadaveric hemipelvises were dissected. A coordinate measuring device measured dimensions and interrelationships of the gluteal muscles, hip external rotators, pectineus, iliopsoas, and joint capsule in reference to osseous landmarks.Results:The vastus tubercle, superomedial border of the greater trochanter, and femoral head-neck junction were distinct and reliable osseous landmarks. The anteroinferior tip of the vastus tubercle was 17.1 mm (95% CI: 14.5, 19.8 mm) anteroinferior to the center of the gluteus medius lateral insertional footprint and was 22.9 mm (95% CI: 20.1, 25.7 mm) inferolateral to the center of the gluteus minimus insertional footprint. The insertions of the piriformis, conjoint tendon of the hip (superior gemellus, obturator internus, and inferior gemellus), and obturator externus were identified relative to the superomedial border of the greater trochanter. The relationship of the aforementioned footprints were 49% (95% CI: 43%, 54%), 42% (95% CI: 33%, 50%), and 64% (95% CI: 59%, 69%) from the anterior (0%) to posterior (100%) margins of the superomedial border of the greater trochanter, respectively. The hip joint capsule attached distally on the proximal femur 18.2 mm (95% CI: 14.2, 22.2 mm) from the head-neck junction medially on average.Conclusion:The vastus tubercle, superomedial border of the greater trochanter, and the femoral head-neck junction were reliable osseous landmarks for the identification of the tendinous and hip capsular insertions on the proximal femur. Knowledge of the interrelationships between these structures is essential for endoscopic navigation and anatomic surgical repair and reconstruction.Clinical Relevance:The qualitative and quantitative clinically relevant anatomic data presented here will aid in the diagnosis of proximal femur pathology and will provide a template for anatomic repair or reconstruction.

SAT0327 Estimation of Enthesitis of Rotator Cuff Shoulder by Ultrasound in Osteoarthritis

BackgroundThe rotator cuff consists of muscles and their tendons: subscapularis, supraspinatus, infraspinatus. The subscapularis tendon inserts in the lesser tuberosity of the humerus. The supraspinatus tendon inserts in the of...

The Synovio-entheseal Complex and Its Role in Tendon and Capsular Associated Inflammation

Tendon, ligament, and capsular insertions are parts of "enthesis organs" whereby the enthesis itself has an elaborate functional integration with the adjacent soft tissues and the synovium in particular. The purpose of this article is to review the sophisticated degree of integration between insertions and adjacent synovium in what has been dubbed "synovio-entheseal complexes" (SEC). SEC arise at multiple sites in the immediate vicinity of insertions and may also arise within the joint capsule at sites well away from enthesis insertions. Not only does this relationship between the enthesis and synovium hold in synovial joints, but it is also crucial for understanding the microanatomical basis for joint disease localization to tendons in the seronegative spondyloarthropathies as well as in other conditions including osteoarthritis. The fibrocartilages at insertions are prone to microdamage whereas this tissue is completely devoid of immune cells. In healthy conditions, the synovium lubricates and nourishes the entheseal associated fibrocartilages, but damage or aberrant tissue repair responses at the insertion may manifest as an immediately adjacent synovitis or tenosynovitis, given that the synovium has resident immune cell populations and the ability to undergo substantial hyperplasia. Therefore SEC are likely to represent key orchestrators that contribute to joint inflammation by mechanisms that have been hitherto poorly appreciated.

Analysis of the Capsule and Ligament Insertions About the Acromioclavicular Joint: A Cadaveric Study

The purpose of this study was to analyze the capsular and ligamentous insertions about the acromioclavicular (AC) joint to determine the amount of bone that can be removed without destabilizing the joint. We dissected 28 cadaveric shoulders. The AC ligament insertions were measured under loupe magnification with a digital caliper on the acromial and clavicular sides on the anterior, posterior, superior, and inferior edges. We measured the distance to the coracoacromial (CA) and coracoclavicular ligaments. In addition, the axial and coronal angle of the AC joint was measured. The AC joint capsular insertion on the acromion begins, on average, 2.8 mm (range, 2.3 to 3.3 mm) from the medial acromion and begins on the lateral clavicle a mean of 3.5 mm (range, 2.9 to 3.9 mm) from the distal clavicle. The mean capsular width ranged from 1.6 to 2.9 mm. The mean distance from the medial acromion to the CA ligament insertion was 3.5 mm. The mean axial angle of the AC joint was 51 degrees , with a 12 degrees coronal angle. The mean distance from the lateral clavicle to the start of the trapezoid ligament was 14.7 mm, and that to the conoid ligament was 32.1 mm. An anatomic-based recommendation for safe AC joint resection is that 2 to 3 mm of the medial acromion and 3 to 4 mm of the distal clavicle can be resected without removing the AC capsular insertions. The trapezial and CA attachments are in close proximity to the AC capsular insertions. Medial resections greater that 15 mm will begin to take down the trapezoid ligament. Arthroscopic bone resection should be directed into the AC joint at approximately 50 degrees in the axial plane and 12 degrees in the coronal plane for safe symmetric resection. These anatomic measurements suggest that AC joint resections (5 to 7 mm) with 2 to 3 mm from the acromial side and 3 to 4 mm from the clavicular side will not disrupt the stabilizing ligaments of the AC joint after distal clavicle resection.

Ultrasound and clinical evaluation of quadricipital tendon enthesitis in patients with psoriatic arthritis and rheumatoid arthritis.

Enthesitis is an inflammatory lesion of the tendon, ligament and capsular insertions into the bone, and it is a fundamental element in the diagnosis of spondyloarthropathies. Sonography is the method of choice for studying periarticular soft tissues because it is capable of detecting both the early (oedema, thickening) and late alterations (erosions and enthesophytes); it is also an inexpensive, biologically harmless and easily repeatable technique. The aim of this study was to compare the prevalence of quadricipital enthesitis in psoriatic arthritis (PsA) and rheumatoid arthritis (RA) patients, and to document any clinical and echostructural differences in this lesion between the two diseases. The results show that enthesitis is more frequent in PsA patients, more than half of whom are asymptomatic. Knee inflammation was found in the PsA patients with enthesitis regardless of the concomitant presence of joint effusion; none of the RA patients suffered from enthesitis alone. Quadricipital enthesitis is more frequent in male patients. There was no significant correlation between the presence of peripatellar psoriatic lesions and enthesitis. Sonographic examinations of patients with enthesitis revealed that those with RA had predominantly inflammatory lesions, whereas PsA patients also showed major new bone deposition.

Ultrasound and clinical evaluation of quadricipital tendon enthesitis in patients with psoriatic arthritis and rheumatoid arthritis.

Enthesitis is an inflammatory lesion of the tendon, ligament and capsular insertions into the bone, and it is a fundamental element in the diagnosis of spondyloarthropathies. Sonography is the method of choice for studying periarticular soft tissues because it is capable of detecting both the early (oedema, thickening) and the late alterations (erosions and enthesophytes); it is also an inexpensive, biologically harmless and easily repeatable technique. The aim of this study was to compare the prevalence of quadricipital enthesitis in psoriatic arthritis (PsA) and rheumatoid arthritis (RA) patients, and to document any clinical and echostructural differences in this lesion between the two diseases. The results show that enthesitis is more frequent in PsA patients, more than half of whom are asymptomatic. Knee inflammation was found in the PsA patients with enthesitis regardless of the concomitant presence of joint effusion; none of the RA patients suffered from enthesitis alone. Quadricipital enthesitis is more frequent in male patients. There was no significant correlation between the presence of peripatellar psoriatic lesions and enthesitis. Sonographic examinations of patients with enthesitis revealed that those with RA had dominantly inflammatory lesions, whereas PsA patients also showed major new bone deposition.

Evidence of a hypermineralised calcified fibrocartilage on the human femoral neck and lesser trochanter.

Femoral neck fractures are a major cause of morbidity and mortality in elderly humans. In addition to the age-related loss of cancellous bone, changes to the microstructure and morphology of the metaphyseal cortex may be a contributing factor in osteoporotic hip fractures. Recent investigations have identified a hypermineralised tissue on the neck of the femur and trochanteric region that increases in fractional area with advancing age in both males (Boyce & Bloebaum, 1993) and females (Vajda & Bloebaum, 1999). The aim of this study was to determine if the hypermineralised tissue previously observed on the proximal femur is calcified fibrocartilage. Regional variations in the fractional area of hypermineralised tissue, cortical bone, and porosity of the cortical bone along the neck of the femur and lesser trochanter were also quantified. Comparison of back scattered electron and light microscope images of the same area show that regions of hypermineralised tissue correlate with the regions of calcified fibrocartilage from tendon and capsular insertions. The hypermineralised tissue and calcified fibrocartilage had similar morphological features such as the interdigitations of the calcified fibrocartilage into the bone, lacunar spaces, and distinctly shaped pores adjacent to the 2 tissues. Regions of the neck that did not contain insertions were covered with periosteum. There were no regional differences (P > 0.05) on the superior and inferior femoral neck in terms of the percentage area of hypermineralised calcified fibrocartilage, cortical bone, or cortical bone porosity. The lesser trochanter exhibited regional differences in the fractional area of hypermineralised calcified fibrocartilage (P = 0.007) and cortical bone (P = 0.007) but not porosity of the cortical bone (P > 0.05). The effects of calcified fibrocartilage on femoral neck periosteal expansion, repair, and mechanics are unknown, but may play a role in osteoporotic fractures and intracapsular fracture healing.

Impingement of the deep surface of the subscapularis tendon and the reflection pulley on the anterosuperior glenoid rim: A preliminary report

Sixteen patients underwent detailed arthroscopic evaluation; all had moderate to severe, primarily unexplained shoulder pain provoked by anterior elevation and internal rotation, and all were nonresponsive to subacromial injection of local anesthetic. None of the patients had any symptoms or signs of instability. Partial subscapularis lesions were documented in 10 of 13 patients who had undergone preoperative arthro–magnetic resonance imaging. At arthroscopy, an isolated lesion of the common humeral insertion of the superior glenohumeral and coracohumeral ligaments (a so-called pulley lesion) was found in 3 cases, a lesion associating a pulley and an articular side partial subscapularis lesion in 10 cases, and an isolated articular side partial subscapularis tear in 3 cases. The most painful movement, which consisted of flexion and internal rotation, caused impingement of the involved ligamentous and/or capsular insertions in all patients. If the arm was elevated above 90 degrees, the zone of mechanical contact was between the long head of the biceps and the pulley region and superiormost aspect of the labrum; if elevation was decreased, impingement occurred between the tendinous insertion of the subscapularis and the anterior glenoid labrum and rim. This study suggests that in addition to the posterosuperior impingement of the supraspinatus tendon originally described by Walch, anterosuperior impingement of the deep surface of the subscapularis is a form of intraarticular impingement responsible for painful structural disease of the shoulder. (J Shoulder Elbow Surg 2000;9:483-90.)

MR imaging of the labral-capsular complex: normal variations.

Understanding the normal anatomy of the shoulder and its variations is important for the proper interpretation of MR images. This study was performed to describe variations in the normal labral-capsular complex as seen on MR images. MR images of 52 shoulders in 30 asymptomatic volunteers and 27 shoulders of symptomatic patients who had subsequent arthroscopy and/or reconstructive surgery were obtained with 1.5-T MR. The 52 scans of the asymptomatic group were reviewed by three radiologists in conference, and the assessment of labral shapes and capsular insertions was done by consensus. The 27 MR scans of the shoulders in the symptomatic group were reviewed by one radiologist before and after the asymptomatic cases were interpreted. Differences in these two interpretations were shown on receiver-operating-characteristic curves by using the results of subsequent arthroscopy and surgery as the gold standard. The anterior and posterior parts of the labra, respectively, varied in shape but showed several dominant features: triangular (45%, 73%), round (19%, 12%), cleaved (15%, 0%), notched (8%, 0%), flat (7%, 6%), and absent (6%, 8%). Most capsules inserted anteriorly on the labrum (47%) or glenoid rim (49%). All posterior insertions were on the labrum (100%). Intrinsic labral signal was noted on proton density-weighted images, but never on T2-weighted images. Receiver-operating-characteristic curves from interpretations of the symptomatic and clinical cases made before and after evaluation of the asymptomatic shoulders showed the interpretations improved considerably after scans of asymptomatic volunteers were studied. Our study reveals a wide variability in the MR appearance of the labral-capsular complex in asymptomatic shoulders.

Retinyl acetate-induced arthritis in C3H-A(vy) mice.

Severely impaired musculoskeletal mobility in C3H-A(vy) mice was noted during a pharmacologic trial evaluating the antitumorigenic properties of retinyl acetate (RAc). To determine the etiology of this impairment, we studied 103 female C3H-A(vy) mice that were fed RAc in daily doses of 75-300 micrograms or placebo and were killed after 3-16 months. Whole-body radiographs and histologic sections of the hindlimbs were scored for presence and severity of arthritis. C3H-A(vy) mice treated with RAc in any dose had a significantly higher incidence of arthritis than placebo-treated mice. Histologic evidence of enthesopathic disease closely paralleled the radiographic changes and ranged from small enthesophytes at tendinous and capsular insertions to complete periarticular bony bridging. Articular cartilage was not grossly affected. The incidence and severity of arthritis were significantly correlated with the total dose of RAc administered. The bony metaplasia induced by RAc was similar to the pathologic changes caused by other retinoids. This model may be useful for studying the pathogenesis of periarticular bone formation in diffuse idiopathic skeletal hyperostosis and related syndromes.

CT arthrography of capsular structures of the shoulder.

The capsular mechanism of the shoulder joint consists of the joint capsule, which is strengthened by the glenohumeral ligaments and the rotator cuff, the glenoid labrum, and a variable number of synovial recesses. Although the fibrous capsule is a lax structure, the normal function of the capsular mechanism makes it an effective barrier against anterior dislocation, particularly in external rotation. There has been a tendency in the past to overestimate the role of the glenoid labrum in stability of the shoulder joint. In patients with instability, the significance of the capsular attachment or its anomalous insertions to the glenoid has not been adequately recognized. Labral tears may develop as secondary lesions due to repeated dislocations and subluxations rather than representing the primary lesion responsible for instability. Operative visualization of capsular defects or detachments is often difficult. Prior knowledge of these lesions can effectively help the choice of an appropriate surgical procedure and reduce operating time. The results of computed tomographic (CT) arthrography of the shoulder joint in 45 patients are reported and the normal and pathologic variations of the joint capsule and particularly the capsular insertions are described. Configuration of the joint recesses and the glenoid labrum are also evaluated. These CT findings were correlated and verified by surgery or arthroscopy in 26 cases.