The Comma Sign: An Anatomic Study.

The comma sign is a comma-shaped arc of tissue located at the superolateral edge of the subscapularis at its insertion on the humeral head. It consists of the coracohumeral ligament (CHL) and the superior glenohumeral ligament (SGHL). It was recently recognized as an important landmark to aid surgeons in identifying the edge of a torn subscapularis tendon. The exact proportion of CHL and SGHL has not been precisely defined. The goal of this study was to dissect and more accurately define the composition of the comma tissue and its exact relationship to the subscapularis tendon. A total of 8 fresh frozen cadaveric shoulder specimens (mean age, 74 years; 5 male, 3 female) were dissected via a wide deltopectoral approach. Anatomic landmarks were identified, and measurements were taken with a digital caliper. The midpoint width of the SGHL and CHL and the composite insertion width of the subscapularis were measured. Measurements were taken 3 times each and averaged to calculate mean width. Mean midpoint width of the SGHL, CHL, and composite insertion was 5.99 mm (range, 5.25-6.91 mm), 5.13 mm (range, 4.28-5.72 mm), and 9.93 mm (range, 6.69-12.05 mm), respectively. The comma sign consists of approximately half SGHL (54%) and half CHL (46%) at its insertion to the subscapularis tendon, with an approximate width of 1 cm. With the increase in arthroscopic subscapularis repairs, knowledge of these dimensions will aid surgeons in discerning the comma tissue from other capsular elements and ultimately help in surgical restoration of native anatomy.

The Comma Sign: The Coracohumeral Ligament and Superior Glenohumeral Ligament Exhibit Similar Quantitative Characteristics With Terminal Confluence at the Subscapularis Insertion.

PURPOSE: The purpose of this morphologic cadaveric study was to quantitatively define the composition of the previously described comma tissue along with its relation to the subscapularis tendon insertion. METHODS: Fresh frozen cadaveric shoulder specimens were included for analysis. The coracohumeral ligament (CHL) was exposed at its origin along the base of the coracoid process and freed laterally along its course to the lesser tuberosity adjacent to the bicipital groove. The superior glenohumeral ligament (SGHL) was identified and traced along its course deep to the CHL within the rotator interval with insertion onto the superior aspect of the lesser tuberosity. The midpoint diameters of the SGHL and CHL and their composite insertional diameters on the subscapularis tendon insertion and lesser tuberosity were measured with digital calipers. The mean diameter was determined from 3 measurements taken of each ligament. RESULTS: Eight specimens were included. With the use of digital calipers, the mean midpoint diameters of the SGHL and CHL were identified as 5.99 mm (range, 5.25-6.91 mm) and 5.13 mm (range, 4.28-5.72 mm), respectively. The composite insertional diameter of the SGHL and CHL on both the lesser tuberosity and humeral insertion of the subscapularis tendon was 9.93 mm (range, 6.69-12.05 mm). At its insertion, the SGHL and CHL comprised 54% and 46% of the comma tissue, respectively. Additionally, all specimens were identified as showing a confluence of the SGHL and CHL composite insertion with the subscapularis tendon at the point of its humeral head insertion. CONCLUSIONS: The comma tissue is a pivotal structure for the identification, mobilization, and repair of retracted subscapularis tendon tears. Therefore, quantitative knowledge of the midpoint diameter, insertional diameter, and composite distribution of the CHL and SGHL provided by this morphologic cadaveric analysis may aid surgeons in their efforts to restore the native anatomy. CLINICAL RELEVANCE: Subscapularis tendon tears have often been under-addressed during rotator cuff repair. The comma tissue has been described as an anatomic structure that can aid in the identification, mobilization, and repair of retracted subscapularis tendon tears. Therefore, quantitative knowledge of this important arthroscopic landmark may aid surgeons in their efforts to restore the native anatomy

Magnetic hydroxyapatite nanomaterial–cyclodextrin tethered polymer hybrids as anticancer drug carriers

Osteosarcoma, the most common bone cancer, leads to a poor survival rate of patients. Drug targeting employing hydroxyapatite (HAp)-based nanocarriers represents a fascinating choice for non-invasive treatment of osteosarcoma. Herein, we report strontium-doped (Sr-HAp) and iron- and strontium-co-doped (Sr,Fe-HAp) hydroxyapatite nanoparticles as novel materials that deliver doxorubicin to bone cancer cells. A platinum-complexed and cyclodextrin-functionalized chitosan derivative is utilized to coat the NPs. Sr-HAp (aspect ratio ∼20) and Sr,Fe-HAp (aspect ratio ∼3) nanoparticles are formed as nanowhiskers and nanorods, respectively, as revealed by transmission electron microscopy. Strontium ferrite NPs are synthesized and their properties are compared with those of the Sr/Sr,Fe-doped HAp NPs. These ferrite NPs show ferromagnetic behavior, as opposed to Sr-HAp and Sr,Fe-HAp. The latter two respectively display paramagnetic and superparamagnetic behaviors. The loading percentage of the anticancer drug, Doxorubicin (Dox), in the nanocarriers is high and the release of Dox is sustained at physiological pH. The Dox-loaded nanocarriers are tested for their in vitro cytotoxicity against lung, cervical, liver, and bone cancer cell lines. In general, the efficacy of Dox is not diminished on loading in the nanocarriers. In addition, the Dox-carriers demonstrate a time- and dose-dependent cytotoxicity. The efficacy is enhanced in the case of Dox-loaded carriers on MG-63 (osteosarcoma) cell lines. The anticancer activity is tested in vivo on both male and female albino mice. Enhanced chemotherapeutic potential is observed for Dox-loaded Sr,Fe-HAp in a metastatic model of MG-63. The platinum derivative polymer possesses its own therapeutic effect and contributes to the general activity. The novel polymer-HAp nanohybrid represents an effective nanocarrier for the treatment of osteosarcoma