Reliability of a CT reconstruction for preoperative surgical planning in the arthroscopic Latarjet procedure.

PURPOSE: The arthroscopic Latarjet procedure has provided reliable results in the treatment of anterior shoulder instability. However, this procedure remains technically challenging and is related to several complications. The morphology of the coracoid and the glenoid are inconsistent. Inadequate coracoid and glenoid preparing may lead to mismatching between their surfaces. Inadequate screws lengthening and orientation are a major concern. Too long screws can lead to suprascapular nerve injuries or hardware irritation, whereas too short screws can lead to nonunions, fibrous unions or migration of the bone block. The purpose of the study was to investigate the application of virtual surgical planning and digital technology in preoperative assessment and planning of the Latarjet procedure. METHODS: Twelve patients planned for an arthroscopic Latarjet had a CT scan evaluation with multi-two-dimensional reconstruction performed before surgery. Interobserver and intraobserver reliability were evaluated. The shape of the anterior rim of the glenoid and the undersurface of the coracoid were classified. Coracoid height was measured, respectively, at 5 mm (C1) and 10 mm (C2) from the tip of the coracoid process, corresponding to the drilling zone. Measurements of the glenoid width were then taken in the axial view at 25 % (G1) and 50 % (G2) of the glenoid height with various α angles (5°, 10°, 15°, 20°, 25°, 30°) 7 mm from the anterior glenoid rim. Shapes of the undersurface of the coracoid and the anterior rim of the glenoid were noted during the surgical procedure. Post-operative measurements included the α angle. RESULTS: Concerning coracoid height measurements, there was an almost perfect to substantial intra- and inter-reliability, with values ranging from ICC = 0.75-0.97. For the shape of the coracoid, concordances were, respectively, perfect (ICC = 1) and almost perfect (0.87 [0.33; 1]) for the intra- and interobserver reliabilities. Concerning the glenoid, concordance was always almost perfect for 50 % height. Concordance was almost perfect for 25 % height 15° and 30° for inter- and intraobserver, for intraobserver at 0° and 25°. All the other values were still showing moderate concordance. Shape of the coracoid analysis reproducibility was perfect for both intra- and interobserver ICC = 1. There was a total agreement (ICC = 1) between the preoperative evaluation of the shape of the glenoid and the coracoid and the intraoperative assessment. CONCLUSION: The ideal and accurate preoperative planning of screwing of the coracoid graft in the arthroscopic Latarjet can be achieved in the real surgery assisted by the virtual planning. The clinical importance of this study lies in the observation that this new preoperative planning could offer a simple, effective and reproducible tool for surgeons helping them to prepare in the best possible way a technically challenging procedure usually associated with a high rate of complications.

Preoperative CT planning of screw length in arthroscopic Latarjet.

PURPOSE: The Latarjet procedure has shown its efficiency for the treatment of anterior shoulder dislocation. The success of this technique depends on the correct positioning and fusion of the bone block. The length of the screws that fix the bone block can be a problem. They can increase the risk of non-union if too short or be the cause of nerve lesion or soft tissue discomfort if too long. Suprascapular nerve injuries have been reported during shoulder stabilisation surgery up to 6 % of the case. Bone block non-union depending on the series is found around 20 % of the cases. The purpose of this study was to evaluate the efficiency of this CT preoperative planning to predict optimal screws length. The clinical importance of this study lies in the observation that it is the first study to evaluate the efficiency of CT planning to predict screw length. METHODS: Inclusion criteria were patients with chronic anterior instability of the shoulder with an ISIS superior to 4. Exclusion criteria were patients with multidirectional instability or any previous surgery on this shoulder. Thirty patients were included prospectively, 11 of them went threw a CT planning, before their arthroscopic Latarjet. Optimal length of both screws was calculated, adding the size of the coracoid at 5 and 15 mm from the tip to the glenoid. Thirty-two-mm screws were used for patients without planning. On a post-operative CT scan with 3D reconstruction, the distance between the screw tip and the posterior cortex was measured. A one-sample Wilcoxon test was used to compare the distance from the tip of the screw to an acceptable positioning of ±2 mm from the posterior cortex. RESULTS: In the group without planning, screw 1 tended to differ from the acceptable positioning: mean 3.44 mm ± 3.13, med 2.9 mm, q1; q3 [0.6; 4.75] p = 0.1118, and screw 2 differed significantly from the acceptable position: mean 4.83 mm ± 4.11, med 3.7 mm, q1; q3 [1.7; 5.45] p = 0.0045. In the group with planning, position of screw 1 or 2 showed no significant difference from the acceptable position: mean 2.45 mm ± 2.07 med 1.8 mm, q1; q3 [1; 3.3] p = 1; mean 2.75 mm ± 2.32 med 2.3 mm, q1; q3 [1.25; 3.8] p = 0.5631. CONCLUSION: Unplanned Latarjet can lead to inaccurate screw length especially in the lower screw and can increase the risk of non-union and nerve damage. The clinical relevance of this article is that CT planning of screw length before surgery showed good results on post-operative CT.

Graft position and fusion rate following arthroscopic Latarjet.

PURPOSE: The arthroscopic Latarjet procedure is recently becoming an increasingly popular technique. Nevertheless, position and fusion of the autograft had not been well studied yet. The purpose of this study was to assess the positioning of the coracoid graft and the fusion rate on CT scan in the arthroscopic Latarjet procedure. METHODS: The study design was a prospective series of 19 consecutive patients who received arthroscopic Latarjet procedure. Radiological assessment on CT scan performed 3 months post-operatively included an analysis of the fusion and the position of the coracoid bone graft using a validated method. 02:30-04:20 was considered an ideal positioning in the sagittal view. In the axial view, the positioning was considered as flush, congruent, medial, too medial, or lateral. RESULTS: The median age of patients was 27.6 (±6.9). Mean operative time was of 161 min ±34.8. The fusion rate was of 78 %. Coracoid grafts were positioned 01:52 h (56° ± 14°) to 4:04 h (122° ± 12.5°). In the axial view, 32 % of the grafts positioning were considered as flush, 38 % as congruent, 30 % as medial, and 6 % too medial. No lateral position was noted. Two complications occurred, one graft fracture during screwing requiring opening conversion and an early case of osteolysis in a medial-positioned graft. CONCLUSION: The arthroscopic Latarjet procedure is a technically challenging technique that provides satisfactory fusion rate and graft positioning with a low complication rate. The clinical importance of this study lies in the observation that it is the first study to evaluate the position of the coracoid bone graft in arthroscopic Latarjet according to a detailed and validated method. LEVEL OF EVIDENCE: IV.