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Background: Since the description of the arthroscopic Latarjet technique, discussion about the superiority of the open or arthroscopic procedure has arisen. The appropriate placement of the coracoid graft (CG) on the anterior glenoid neck is reported to be the most important step of the Latarjet procedure. Purpose: To verify if there are differences in the parameters that may affect the final position and fixation of CG obtained from the open and arthroscopic Latarjet techniques. Study Design: Controlled laboratory study. Methods: Twenty fresh-frozen human paired cadaveric shoulder specimens were randomly distributed in 2 surgery groups (open group [OG] and arthroscopic group [AG]) with 10 specimens in each. Two surgeons, each with experience performing open and arthroscopic Latarjet techniques, executed these procedures: one surgeon performed all open techniques, and the other performed all arthroscopic techniques, respectively. After surgery, a computerized tomography scan was performed. The surgical time, the position of each CG, a series of variables that might affect the CG fixation, and the level of the subscapularis muscle split were evaluated. Results: The mean surgical time was significantly longer in the AG (mean, 26 minutes for OG and 57 minutes for AG). Three intraoperative complications (30%) were identified in the AG, consisting of graft fractures. The CG was determined to be in an optimal cranial-caudal position in 90% of specimens of the OG and 44% of the AG (Fisher, P = .057). In both groups, the CG was placed in an optimal medial-lateral position in all specimens. In the OG, the degree of parallelism between the major axes of the glenoid surface and CG was significantly greater than in the AG (mean, 3.8º for OG and 15.1º for AG). No significant differences were observed in superior and inferior screw orientation between the groups. In the longitudinal and transverse directions, significant differences were found in the centering of the superior screw, being closer to the ideal point in the OG than in the AG. The location where the longitudinal subscapularis muscle split was performed was significantly higher in the AG. Conclusion: The open Latarjet technique required less surgical time; presented a lower number of intraoperative complications; and allowed more adequate placement of the CG, better centering of the screws, and a subscapularis muscle split closer to the ideal position. Clinical Relevance: The reported benefits of the arthroscopic Latarjet technique seem less clear if we take into account the added surgery time and complications.

The ontogenic development of the sphincter iris has been studied by immunocytochemistry and standard staining on chick embryos from stage 25 HH to the time of hatching. We have used the monoclonal antibody 13F4, a highly specific marker of muscular cells. We have observed three different regions in the iris. In the pupillary region, immunoreactive cells are in continuous contact with the inner epithelium of the pupillary margin. In the intermediate region, the outer epithelium forms buds of pigmented cells that emigrate toward the stroma. In this epithelium cells that are totally or partially unpigmented exist, and they are 13F4 positive. In the sphincter we have observed 13F4 positive cells with melanin granules. In the ciliary region, the immunoreactivity appears in dispersed mesenchymal cells. The present findings are consistent with a triple origin of the sphincter iris in the chick embryo. This muscle is derived from the inner epithelium of the pupillary margin, the intermediate region of the outer epithelium, and from the mesenchymal cells. The cells of the inner epithelium of the pupillary margin are differentiated into smooth muscle cells, and the remaining cells form striated muscle cells.

It has long been maintained that the ciliary muscle derives from mesenchymal cells. The embryonic development of the avian ciliary muscle was studied in chick embryos from stage 25 HH to the time of hatching. Serial sections of the eye were stained routinely or immunocytochemically using the monoclonal antibody 13F4, which recognizes a cytoplasmic antigen specific for all types of muscle cells. We found that the mesenchymal immunoreactive cells, at stage 37 HH, are arranged in two distinct orientations forming the anterior and posterior portions of the ciliary muscle. At stages 38 and 39 HH the pigmented epithelium contained 13F4 positive cells, which detach from the epithelium and apparently migrate into stroma. These epithelial cells may differentiate into muscle cells. Within this same time period a progressive accumulation of myoblasts was detected between the pigmented epithelium and the ciliary muscle. Some myoblasts containing melanin were also observed. At stage 40 HH the internal portion of the ciliary muscle was visible. These findings indicate that the immunopositive epithelial cells participate in the formation of the internal portion of the muscle. We conclude that the ciliary muscle derives not only from the mesenchymal cells but also from the pigmented epithelium.