Best implant choice for coracoid graft fixation during the Latarjet procedure depends on patients' morphometric considerations.

PURPOSE

To assess the anthropometric dimensions of the coracoid process and the glenoid articular surface and to determine possible implications with the different commercially available Latarjet fixation techniques.

METHODS

In a total of 101 skeletal scapulae the glenoid length (GL), the glenoid width (GW), the coracoid length (CL), the coracoid width (CW) and the coracoid thickness (CTh) were measured. In order to assess the ability of the transferred coracoid to restore the glenoid anatomy we created a hypothetical model of 10%, 15%, 20%, 25% and 30% glenoid bone loss. We analyzed four common surgical fixation techniques for the Latarjet procedure (4.5 mm screws, 3.75 mm screws, 3.5 mm screws, and 2.8 mm button). The distances from the superior-inferior and medio-lateral limits of the coracoid using the four different fixation methods were calculated. We hypothesized that the "safe distance" between the implant and the coracoid osteotomy should be at least equal to the diameter of the implant.

RESULTS

The intra and inter-observer reliability tests were almost perfect for all measurements. The mean GH was 36.8 ± 2.5 mm, the GW 26.4 ± 2.2 mm, the CL 23.9 ± 3 mm, the CW 13.6 ± 2.mm, and the mean CTh was 8.7 ± 1.3 mm. The CL was < 25 mm in 46% of the cases. In cases with 25% and 30% bone loss, the coracoid graft restored the glenoid anatomy in 96% and 79.2% of the cases. With the use of the 4.5 mm screws the "safe distance" was present in 56% of the cases, with the 3.75 mm screws in 85%, with the 3.5 mm screws in 87%, and with the 2.8 mm button in 98% of the cases. The distance from the medio-lateral limit of the coracoid could be significantly increased (up to 9 mm) when smaller-button implants are used.

CONCLUSIONS

The coracoid graft could not always restore glenoid defects of 30%. Larger implants could be positioned too close to the osteotomy and the "medio-lateral offset" of the coracoid could be increased with smaller implants.