Ryuzo Arai

Subscapularis Tendon Tear: An Anatomic and Clinical Investigation

PURPOSE The purpose of this study was to clarify anatomically and clinically how the subscapularis tendon supports the superior portion of the biceps tendon to the intertubercular groove. METHODS Thirty-three embalmed shoulder girdles were examined to investigate the subscapularis tendon and the pathway of the biceps tendon. In addition, operation records of 435 consecutive arthroscopic rotator cuff repairs were retrospectively reviewed. RESULTS Anatomically, the superior-most insertion of the subscapularis tendon was located on the upper margin of the lesser tuberosity. In addition, a thin tendinous slip extended from the insertion and attached to the fovea capitis of the humerus. The insertion, the tendinous slip, and the lateral portion of the cranial part of intramuscular tendons were in direct contact with the inferior side of the biceps tendon at its corner portion. The clinical study showed that 27.4% of rotator cuff tears (119/435) had subscapularis tendon tears. In cases with an unstable biceps tendon there was no intact subscapularis tendon. The superior-most insertion of the subscapularis tendon was involved in all transverse tears. Of 29 full-thickness transverse tears, 13 (44.8%) showed intra-articular dislocation. CONCLUSIONS The trochlea-like structure was composed of the superior-most insertion, the tendinous slip, and the lateral portion of the cranial part of intramuscular tendons supporting the biceps tendon. The transverse tear of the subscapularis tendon, which included this trochlea-like structure, often leads to intra-articular dislocation of the biceps tendon. CLINICAL RELEVANCE Instability of the biceps tendon should be carefully assessed because it is associated with subscapularis tendon tears at a very high incidence. When we repair a transverse tear of the subscapularis tendon, we should widely fix sufficiently strong tissue to support the biceps tendon on the uppermost margin, not on the anteromedial portion, of the lesser tuberosity.

Functional anatomy of the superior glenohumeral and coracohumeral ligaments and the subscapularis tendon in view of stabilization of the long head of the biceps tendon

BACKGROUND Various findings in the lateral rotator interval to support the long head of the biceps tendon have been reported. The purpose of this study was to clarify the functional anatomy regarding the stabilization of the biceps tendon. MATERIAL AND METHODS Twenty embalmed shoulders were used for anatomic study, and 5 specimens of the anterosuperior part of the glenohumeral joint were histologically studied. RESULTS Anatomically, the most superior part of the subscapularis tendon was attached to the upper margin of the lesser tuberosity and extended as a thin tendinous slip to the fovea capitis of the humerus. The superior glenohumeral ligament ran spirally along the biceps tendon. Histologically, the superior glenohumeral ligament was attached to the tendinous slip. There was no clear boundary between the superior glenohumeral and coracohumeral ligament. CONCLUSION To keep the biceps tendon in place and stabilized, tension in the superior glenohumeral ligament and the buttress support of the most superior insertion point of the subscapularis from behind the ligament may be necessary. LEVEL OF EVIDENCE Basic Science.

Effect of early implementation of electrical muscle stimulation to prevent muscle atrophy and weakness in patients after anterior cruciate ligament reconstruction

OBJECTIVE Following anterior cruciate ligament (ACL) reconstruction, restricted weight bearing and immobilization results in thigh and calf muscle atrophy and weakness. The purpose of this study was to assess the effect of electrical muscle stimulation (EMS) on prevention of muscle atrophy in patients during the early rehabilitation stage after ACL reconstruction. METHODS Twenty patients with acute ACL tears were divided into two groups randomly. The control group (CON group) participated in only the usual rehabilitation program. In addition to this protocol, the electrical muscle stimulation group (EMS group) received EMS training using the wave form of 20 Hz exponential pulse from the 2nd post-operative day to 4 weeks after the surgery. RESULTS Muscle thickness of vastus lateralis and calf increased significantly 4 weeks after surgery in the EMS group, while it decreased significantly in the CON group. The decline of knee extension strength was significantly less in the EMS group than in the CON group at 4 weeks after the surgery, and the EMS group showed greater recovery of knee extension strength at 3 months after surgery. CONCLUSIONS EMS implemented during the early rehabilitation stage is effective in maintaining and increasing muscle thickness and strength in the operated limb.

The anatomy of the coracohumeral ligament and its relation to the subscapularis muscle

BACKGROUND Only a few reports describe the extension of the coracohumeral ligament to the subscapularis muscle. The purposes of this study were to histo-anatomically examine the structure between the ligament and subscapularis and to discuss the function of the ligament. METHODS Nineteen intact embalmed shoulders were used. In 9 shoulders, the expansion of the ligament was anatomically observed, and in 6 of these 9, the muscular tissue of the supraspinatus and subscapularis was removed to carefully examine the attachments to the tendons of these muscles. Five shoulders were frozen and sagittally sectioned into 3-mm-thick slices. After observation, histologic analysis was performed on 3 of these shoulders. In the remaining 5 shoulders, the coracoid process was harvested to investigate the ligament origin. RESULTS The coracohumeral ligament originated from the horizontal limb and base of the coracoid process and enveloped the cranial part of the subscapularis muscle. The superficial layer of the ligament covered a broad area of the anterior surface of the muscle. Laterally, it protruded between the long head of the biceps tendon and subscapularis and attached to the tendinous floor, which extended from the subscapularis insertion. Histologically, the ligament consisted of irregular and sparse fibers abundant in type III collagen. CONCLUSION The coracohumeral ligament envelops the whole subscapularis muscle and insertion and seems to function as a kind of holder for the subscapularis and supraspinatus muscles. The ligament is composed of irregular and sparse fibers and contains relatively rich type III collagen, which would suggest flexibility.

Ultrasound Can Detect Macroscopically Undetectable Changes in Osteoarthritis Reflecting the Superficial Histological and Biochemical Degeneration: Ex Vivo Study of Rabbit and Human Cartilage

Recognizing subtle cartilage changes in the preclinical stage of osteoarthritis (OA) is essential for early diagnosis. To this end, the ability of the ultrasound signal intensity to detect macroscopically undetectable cartilage change was investigated. In this study, cartilage of rabbit OA model and human OA samples was examined by macroscopic evaluation, ultrasound signal intensity, histology with Mankin scores, and Fourier transform infrared imaging (FTIRI) analysis. Rabbit OA was induced by anterior cruciate ligament transection and evaluated at 1, 2, 4 and 12 weeks. Twenty human samples were harvested during total knee arthroplasty from OA patients who had macroscopically normal human cartilage (ICRS grade 0) on the lateral femoral condyle. In the animal study, there was no macroscopic OA change at 2 weeks, but histology detected degenerative changes at this time point. Ultrasound signal intensity also detected degeneration at 2 weeks. In human samples, all samples were obtained from macroscopically intact site, however nearly normal (0≤ Mankin score <2), early OA (2≤ Mankin score <6), and moderate OA (6≤ Mankin score <10) samples were actually intermixed. Ultrasound signal intensity was significantly different among these 3 stages and was well correlated with Mankin scores (R = −0.80) and FTIR parameters related to collagen and proteoglycan content in superficial zone. In conclusion, ultrasound can detect microscopic cartilage deterioration when such changes do not exist macroscopically, reflecting superficial histological and biochemical changes.

Effects of trunk rotation on scapular kinematics and muscle activity during humeral elevation

Trunk rotation often accompanies humeral elevation, during daily activities as well as sports activities. Earlier studies have demonstrated that changes in spinal posture contribute to scapular motion during humeral elevation. However, the effect of trunk rotation on scapular kinematics during humeral elevation has received scant attention. This study aimed to clarify how trunk rotation affects scapular kinematics and muscle activities during humeral elevation. Electromagnetic motion capture and electromyography were used to assess scapular and clavicular motion and muscle activity in the right and left sides of 12 healthy young men. The subjects were seated and instructed to elevate both arms with the trunk in neutral, ipsilaterally rotated, or contralaterally rotated position. Ipsilaterally rotated trunk position decreased the internal rotation (by 5°, relative to neutral trunk position) and increased the upward rotation (by 4°, relative to neutral trunk position) of the scapula. Trunk position did not affect clavicular motion during humeral movement. Electromyography showed that contralaterally rotated trunk position increased the activity of the upper trapezius and serratus anterior muscles and decreased the activity of the lower trapezius. Therapists should consider the importance of trunk rotation, which may be the key to developing more efficient rehabilitation programs.

Longitudinal evaluation of cartilage after osteochondral autogenous transfer with delayed gadolinium-enhanced MRI of the cartilage (dGEMRIC)

The aim was to use repeat delayed gadolinium‐enhanced magnetic resonance imaging of cartilage (dGEMRIC) to estimate glycosaminoglycan (GAG) content in reparative cartilage after osteochondral autogenous transfer (OAT). The study group comprised 7 knees of 7 patients that were examined three times by dGEMRIC, at 3, 6, and 12 months using a 1.5 Tesla MRI system in both OAT operated and nonoperated condyles at 90 min after the injection. The gadolinium diethylene triamine pentaacetic acid (Gd‐DTPA)2− containing contrast medium (0.2 mmols/kg) was injected intravenously. The mean T1 values of the plug cartilage at 3, 6, and 12 months after OAT was 230 ± 40, 213 ± 31, and 230 ± 23 ms (mean ± SD), respectively. There were differences between the plug and control cartilage at 3 (p < 0.01) and 12 (p < 0.05) months after OAT, but not at 6 months (p = 0.089). No T1 changes were detected between the plug cartilage at the different time points after OAT. The fact that the GAG content of the OAT plugs were maintained for 12‐month study period suggest that no major deterioration of load‐bearing properties occurs in the cartilage after the OAT.

Fiber components of the shoulder superior labrum

PurposeThe purpose of this study was to investigate the anatomy of the superior glenoid labrum focusing on the fiber arrangement of its components.MethodsForty-nine embalmed shoulder girdles were removed and each posterior capsule was incised. After recording the macroscopic findings 12 superior-half glenoids were histologically examined. In nine serially sectioned glenoids, four were cut parallel to and five were cut vertical to the glenoid surface. The remaining three glenoids were radially sectioned at the clock position for each hour between 10:00 and 14:00.ResultsThe superior labrum had a semi-circular fiber component along the outer margin of the glenoid. In addition, a so-called ‘sheet-like structure’ which branched off the rotator interval and contained many elastic fibers, attached to its anterosuperior portion. The fibers of the sheet-like structure mixes with fibers of the semi-circular component and ran posteriorward. The fibers of the long head of the biceps tendon extended posteriorward from its origin along the glenoid edge. These fibers communicated with other labrum fibers and became a major element of the posterior portion.ConclusionThe superior labrum is not homogenous. The posterior portion mainly consists of the robust fiber component of the long head of the biceps tendon. The anterosuperior portion includes fibers of the sheet-like structure which contains numerous elastic fibers. Tensile stress from the rotator interval might be conveyed to the anterosuperior labrum.

Anatomical study for SLAP lesion repair.

PurposeThe purpose of this study was to meticulously observe the structures around the origin of the long head of the biceps tendon (LHB) in order to propose a method of anatomical superior labrum anterior and posterior repair.MethodsTwenty-eight shoulders of 16 cadavers with intact LHB origin were macroscopically investigated. Among them, 20 shoulders with an intact superior labrum were additionally observed, to determine whether the anterior edge of LHB on the labrum (point ‘A’) was anterior to the supraglenoid tubercle. Serial sections vertical to LHB were observed using ordinary light and polarized microscopy in three glenoids and scanning acoustic microscopy in one.ResultsThe labrum had a meniscal appearance, and no LHB fibre was sent anterior to the anterior edge of the supraglenoid tubercle. ‘A’ was not located more posterior than the supraglenoid tubercle. All specimens had the so-called ‘the sheet-like structure’, in which the portion closer to the LHB origin tends to be stiffer. Fibres of the sheet-like structure ran vertically to LHB.ConclusionFibre orientation and the stiffness of the sheet-like structure suggest its support of LHB. As LHB fibres do not anteriorly cross over ‘A’, ‘A’ could be a landmark for the anterior border of LHB, independent from the sheet-like structure. Considering a previous report mentioning that the horizontal mattress suture maintains the meniscus-like structure which might be sufficient for proper motion of the normal superior labrum, the horizontal mattress suture not crossing over ‘A’ should be recommended from the viewpoint of functional anatomy.

Isometric muscle activation of the serratus anterior and trapezius muscles varies by arm position: a pilot study with healthy volunteers with implications for rehabilitation

BACKGROUND This study aimed to determine the most appropriate angle and moving direction of the arm for improving coordination of the periscapular muscles, including the serratus anterior (SA), upper trapezius (UT), middle trapezius (MT), and lower trapezius (LT). METHODS Muscle activation amplitudes were evaluated in the SA, UT, MT, and LT in 11 healthy subjects by use of surface electromyography. The subjects were asked to maintain the arm position at 5 elevated positions with maximal effort against applied manual forces, which were directed from upper to lower (test 1), lower to upper (test 2), posterior to anterior in the frontal plane and lateral to medial in the sagittal plane (test 3), and anterior to posterior in the frontal plane and medial to lateral in the sagittal plane (test 4). The relative activity of the UT with respect to the SA, MT, and LT was calculated, resulting in the UT/SA, UT/MT, and UT/LT ratios. RESULTS Test 4 in all positions but 150° of elevation in the frontal plane showed high activity of the SA with a low UT/SA ratio. High MT activity with a low UT/MT ratio was observed during test 3 at the 90° elevated position, whereas high LT activity without UT hyperactivation was not found. DISCUSSION To strengthen the periscapular muscles in the balanced condition, horizontal adduction is recommended for the SA. Horizontal abduction at the 90° elevated position should be effective for the MT. Because no technique in this study was effective for the LT, further studies are needed.