A Novel Treatment for Anterior Shoulder Instability

Abstract

Background: Anterior glenohumeral instability with >20% glenoid bone loss is a disorder that can be treated with the Latarjet stabilizing procedure; however, complications are common. The purposes of this study were to (1) evaluate the effect of an anatomic-specific titanium implant produced by 3-dimensional (3D) printing as a treatment option for recurrent shoulder instability with substantial glenoid bone loss and (2) compare the use of that implant with the Latarjet procedure. Methods: Ten fresh-frozen cadaveric shoulders (mean age at the time of death, 78 years) were tested in a biomechanical setup with the humerus in 30° of abduction and in neutral rotation. The shoulders were tested under 5 different conditions: (1) normal situation, (2) creation of an anterior glenoid defect, (3) implantation of an anatomic-specific titanium implant produced by 3D printing, and the Latarjet procedure (4) with and (5) without 10 N of load attached to the conjoined tendon. In each condition, the humerus was translated 10 mm anteriorly relative to the glenoid, and the maximum peak translational force that was necessary for this translation was measured. Results: After creation of the glenoid defect, the mean translational peak force decreased by 30% ± 6% compared with that for the normal shoulder. After restoration of the original glenoid anatomy, the translational force needed to dislocate the humeral head from the glenoid significantly increased compared with that in the defect condition—to 119% ± 16% of normal (p < 0.01) with the 3D-printed anatomic-specific implant and to 121% ± 48% of normal (p < 0.01) following the Latarjet procedure. No significant differences in mean translational force were found between the anatomic-specific implant and the Latarjet procedure (p = 0.72). Conclusions: The mean translational peak force needed to dislocate the humerus 10 mm anteriorly on the glenoid was higher after glenoid restoration with the 3D-printed anatomic-specific implant compared with when the glenoid had a 20% surface defect but also compared with when the glenoid was intact. No differences in mean translational peak force were found between the 3D-printed anatomic-specific glenoid implant and the Latarjet procedure, although there was less variability in the 3D-implant condition. Clinical Relevance: Novel 3D-printing technology could provide a reliable patient-specific alternative to solve problems related to traditional treatment methods for shoulder instability.

Comparison of Glenoid Dimensions Between 3D Computed Tomography and 3D Printing

“…They found no statistically significant difference in the maximum width measurements contrary to the mean difference for the glenoid height which was 3.67±12.04 mm. Willemsen et al in a cadaveric study used 3D printing to produce an anatomy-specific titanium implant to restore a glenoid defect [ 24 ].…”

The Role of 3D Custom Implants in Upper Extremity Surgery

“…Novel 3D-printed arthroplasty designs have also been described for upper extremity bone defects. In the shoulder, Willemsen et al 22 tested a custom 3D-printed implant to restore bone loss in the glenoid as a potential alternative to the Latarjet procedure in shoulder instability. A custom coronoid implant has also been described for bone loss in the setting of elbow instability because no current implant for this exists on the market.…”

Open versus Arthroscopic Latarjet Procedures for the Treatment of Shoulder Instability

“…In 1954, Latarjet described his treatment for recurrent dislocation of shoulder by transposing the coracoid process on the neck of the scapula and securing it with a screw. The following steps were usually followed: coracoid preparation and osteotomy, subscapularis muscle split, preparation of the anterior glenoid neck and fixation of the coracoid graft to the anterior side of the glenoid with two 3.5-mm cannulated cortical screws (2) .…”