Relationship between the Axillary Nerve and Accompanying Vessels and Proximal Humeral Locking Plates in Japanese: An MRI Study.

We investigated the anatomical features of the axillary nerve and its accompanying vessels with respect to the lateral wall of the greater tuberosity, focusing on the relationship between the neurovascular bundle and the proximal humeral locking plates. Magnetic resonance images of 30 Japanese patients' shoulders were examined. Oblique sagittal images across the greater tuberosity and the neurovascular bundle, which contain the axillary nerve and posterior circumflex humeral artery and vein, were obtained. The distance between the superior aspect of the greater tuberosity and the superior and inferior borders of the neurovascular bundles was measured at the anterior, middle, and posterior edges of the greater tuberosity. The neurovascular bundle was 28.5-36.7 mm, 32.6-41.3 mm, and 38.1-47.5 mm distal to the superior aspect of the greater tuberosity at the anterior, middle, and posterior edges, respectively. We evaluated the relationship between the neurovascular bundle and 3 different locking plates, which were placed at the lateral aspect of the greater tuberosity. Only 3 or four locking screws at the most proximal part could be safely inserted without axillary nerve interference.

Coverage of the humeral head by the coracoacromial arch: relationship with rotator cuff tears.

The pathogenetic roles of the coracoacromial arch in the development of rotator cuff tears are still controversial. This study compared the anteroposterior coverage of the humeral head by the coracoacromial arch between shoulders with and without full-thickness rotator cuff tears. Forty-two shoulders from 21 embalmed cadaveric specimens were macroscopically examined. Specimens were divided into 2 groups:shoulders with full-thickness cuff tears (tear group) and those with intact cuff tendons (normal group). The coverage angle of each component of the coracoacromial arch was measured using true lateral photographs. We also measured the angle of the total arc of the coracoacromial arch, as well as the angle of the anterior acromial projection. These data were compared between the tear group and the normal group. Although no significant differences were observed in the total arc of the coracoacromial arch between the groups, the tear group had significantly less coverage by the coracoacromial ligament than did the normal group (p＜0.05). Moreover, greater anterior acromial projection was observed in the tear group (p＜0.05). These results suggest that greater coverage of the bony structures on the rotator cuff may correlate with the development of rotator cuff tears.

Histological analysis of failed cartilage repair after marrow stimulation for the treatment of large cartilage defect in medial compartmental osteoarthritis of the knee.

Bone marrow-stimulating techniques such as microfracture and subchondral drilling are valuable treatments for full-thickness cartilage defects. However, marrow stimulation-derived reparative tissues are not histologically well-documented in human osteoarthritis. We retrospectively investigated cartilage repairs after marrow stimulation for the treatment of large cartilage defects in osteoarthritic knees. Tissues were obtained from patients who underwent total knee arthroplasty (TKA) after arthroscopic marrow stimulation in medial compartmental osteoarthritis. Clinical findings and cartilage repair were assessed. Sections of medial femoral condyles were histologically investigated by safranin O staining and anti-type II collagen antibody. Marrow stimulation decreased the knee pain in the short term. However, varus leg alignment gradually progressed, and TKA conversions were required. The grade of cartilage repair was not improved. Marrow stimulations resulted in insufficient cartilage regeneration on medial femoral condyles. Safranin O-stained proteoglycans and type II collagen were observed in the deep zone of marrow-stimulated holes. This study demonstrated that marrow stimulation resulted in failed cartilage repair for the treatment of large cartilage defects in osteoarthritic knees. Our results suggest that arthroscopic marrow stimulation might not improve clinical symptoms for the long term in patients suffering large osteoarthritic cartilage defects.

Attachment of the anteroinferior glenohumeral ligament-labrum complex to the glenoid: an anatomic study.

PURPOSE: To determine the morphology of the attachment of the anteroinferior glenohumeral ligament-labrum complex (AIGHL-LC) to the anterior rim of the glenoid. METHODS: Sixty-six cadaveric shoulders with a mean age of 81 years were studied. The length of the AIGHL-LC attachment in the superoinferior direction and its depth in the mediolateral direction at the 2-, 3-, 4-, and 5-o'clock positions were measured. The radial histologic sections from the center of the glenoid at the 2- and 4-o'clock positions were used for histologic examinations. RESULTS: The mean length of the AIGHL-LC attachment was 11.7 mm. The mean depth was 4.7 mm (1.6 mm on the articular cartilage and 3.0 mm on the glenoid neck) at the 2-o'clock position, 6.7 mm (2.4 mm and 4.3 mm, respectively) at the 3-o'clock position, 8.4 mm (3.0 mm and 5.4 mm, respectively) at the 4-o'clock position, and 6.8 mm (2.5 mm and 4.3 mm, respectively) at the 5-o'clock position. The depth of the AIGHL-LC attachment was the greatest at the 4-o'clock position (P < .01) and the smallest at the 2-o'clock position (P < .05). Histologically, the AIGHL-LC attached to both the cartilage and bone in 52 shoulders (86.7%) at the 2-o'clock position and in 53 shoulders (88.3%) at the 4-o'clock position. CONCLUSIONS: The depth of the AIGHL-LC attachment was the greatest at the 4-o'clock position and the smallest at the 2-o'clock position. At the 4-o'clock position, the AIGHL-LC attaches to both the articular cartilage and bone in 88% of shoulders whereas it attaches only to bone in 12%. CLINICAL RELEVANCE: This study provides fundamental information on the AIGHL-LC attachment. Because healing of the AIGHL-LC to the articular cartilage cannot be expected, the same attachment area as to the bone and cartilage observed in normal shoulders needs to be created on the glenoid neck during Bankart repair to obtain the physiological strength of the AIGHL-LC.

Humeral head osteonecrosis in an adolescent amateur swimming athlete: a case report.

Osteonecrosis of the humeral head in an adolescent without clear pathogenesis has not been reported in the literature. In this case report, we present such a case of humeral head osteonecrosis in a 15-year-old adolescent. The lesion was located at the subchondral area of the medial part of the humeral head with characteristic appearances on MRI. The shoulder was immobilized in a sling until the pain disappeared, and the patient was told to refrain any kind of sport activities. Bone remodeling was noted five months after the first visit, and it took 2 years for the lesion to be totally healed.

Anatomical and functional segments of the deltoid muscle.

Previous studies showed that the insertion of the intramuscular tendons of the deltoid muscle formed three discrete lines. The purpose of the present study was to establish a new dividing method of the deltoid muscle into various anatomical segments based on the distribution of the intramuscular tendons with their insertions (anatomical study). We further hoped to clarify the relationship between the anatomical segments and their activity pattern assessed by positron emission tomography with [¹8F]-2-fluoro-deoxyglucose (FDG-PET; PET study). Sixty cadaveric shoulders were investigated in the anatomical study. Three tendinous insertions of the deltoid muscle to the humerus were identified. Then, the intramuscular tendons were traced from their humeral insertions to the proximal muscular origins. The extent of each anatomical segment of the muscle including its origin and insertion was determined through careful dissection. Six healthy volunteers were examined using FDG-PET for the PET study. PET images were obtained after exercise of elevation in the scapular plane. On the PET images, margins of each anatomical segment of the deltoid muscle were determined using magnetic resonance images. Then, the standardized uptake value in each segment was calculated to quantify its activity. The anatomical study demonstrated that the deltoid muscle was divided into seven segments based on the distribution of its intramuscular tendons. The PET study revealed that the intake of FDG was not uniform in the deltoid muscle. The area with high FDG intake corresponded well to the individual muscular segments separated by the intramuscular tendons. We conclude that the deltoid muscle has seven anatomical segments, which seem to represent the functional units of this muscle.

GDF-5/7 and bFGF activate integrin alpha2-mediated cellular migration in rabbit ligament fibroblasts.

Cellular activities responding to growth factors are important in ligament healing. The anterior cruciate ligament (ACL) has poor healing potential compared to the medial collateral ligament (MCL). To assess the differences, we investigated the proliferation, migration, adhesion, and matrix synthesis responding to growth factors in rabbit ACL and MCL fibroblasts. ACL cell proliferation to basic fibroblast growth factor (bFGF), bone morphogenetic protein-2, growth and differentiation factor (GDF)-5, and GDF-7 treatment was similar to that of MCL cells. GDF-5 enhanced Col1a1 expression in ACL and MCL fibroblasts up to 4.7- and 17-fold levels of control, respectively. MCL fibroblasts showed stronger migration activities in response to bFGF and GDF-5 than ACL cells. GDF-5/7 and bFGF also changed the stress fiber formation and cellular adhesion by modulating the distribution of integrin alpha2. Functional blocking analyses using anti-integrin alpha2 antibodies revealed that cellular migration responding to growth factors depended on the integrin alpha2-mediated adhesion on type I collagen. The expression of integrin alpha2 was also increased by growth factors in both cells. Our results demonstrate that GDF-5/7 and bFGF stimulate cellular migration by modulating integrin alpha2 expression and integrin alpha2-dependent adhesion, especially in MCL fibroblasts. These findings suggest that the different healing potential between ACL and MCL may be caused by different cellular behavior in the integrin alpha2-mediated cellular migration in response to growth factors.

Disease-specific screening for deep venous thrombosis and pulmonary thromboembolism using plasma D-dimer values after total knee arthroplasty.

We prospectively evaluated the disease-specific features of the early postoperative plasma D: -dimer value and the relationship with deep venous thrombosis and/or pulmonary thromboembolism (DVT/PE) in 95 patients following total knee arthroplasty. Patients in whom DVT/PE was highly suspected were diagnosed by high-resolution multi-detector row computed tomography scanning (MDCT). Forty-nine knees in 46 patients with rheumatoid arthritis (RA, 24 knees) or osteoarthritis (OA, 25 knees) were finally recruited. DVT/PE was detected in 28 (57.1%) of the 49 cases examined by diagnostic MDCT: 12 (50.0%) of the 24 cases of RA, and 16 (64.0%) of the 25 cases of OA. Of these, PE was found in 11 cases (39.2%), but none of them showed clinical symptomatic signs of dyspnea or chest pain. In both RA and OA cases, there were statistically significant differences in the D: -dimer value on postoperative day 3 (P = 0.027) and after day 28 (P = 0.037) between the groups with and without DVT/PE. In OA cases, there were significant differences between the two groups on postoperative days 1 (P = 0.034), 3 (P = 0.020), 5 (P = 0.005), and 7 (P = 0.045), respectively. At the baseline, perioperative D: -dimer levels in the RA group without DVT/PE were higher than in the OA group. However, multivariate logistic regression analysis showed that RA was not a significant risk factor of DVT/PE in comparison with OA. In conclusion, individual evaluation of the D: -dimer level between RA and OA should provide a more precise predictive indicator of early postoperative DVT/PE.