Congruent Concavity Restoration of the Reconstructed Glenoid After the Latarjet Procedure: Compensation for the Position of the Graft.

ABSTRACT

BACKGROUND: Few clinical studies have addressed concavity restoration by natural remodeling after a Latarjet procedure. This study investigated the fibrous tissue and osseous remodeling of the reconstructed glenoid and concavity restoration after a Latarjet procedure using postoperative computed tomographic arthrography (CTA). METHODS: This retrospective study included 31 patients who underwent immediate postoperative computed tomographic (CT) scanning followed by CTA at 6 months postoperatively. We investigated whether fibrous tissue was newly created over the graft, whether the created fibrous tissue restored the congruity of the articular surface and the osseous remodeling of the graft to the glenoid level (whether the osseous portion of the graft was remodeled flush to the glenoid level) and the concavity of the glenoid using the radius of a best-fit circle on the articular surface, and the relationship between the amount of created fibrous tissue and the position of the graft. RESULTS: In all patients, the fibrous tissue on the graft yielded a smooth articular surface, as revealed by the CTA. The mean radius of the entire glenoid, including the transferred graft, was significantly smaller (p = 0.010) at 33.2 ± 8.5 mm than that of the glenoid posterior to the osseous step-off at 37.6 ± 9.4 mm, which is presumed to be the glenoid before the surgical procedure. Despite the congruity of the articular surfaces due to fibrous tissue seen in the CTA, 14 (45%) of 31 patients showed a subchondral osseous step-off on either the medial side or the lateral side in the immediate postoperative CT scans. However, through osseous remodeling, 8 of the 10 grafts with a lateral step-off and 2 of the 4 grafts with a medial step-off converted to a flush position. The position of the step-off was correlated with the thickness of the fibrous tissue, with a tendency for thicker tissue in cases of a step-off on the medial side (p = 0.014). CONCLUSIONS: Fibrous tissue formation plus remodeling of the transferred graft resulted in the restoration of a congruent concavity after a Latarjet procedure by compensating for initially non-flush positioning of the graft. However, due to the small sample size in our study, clinical outcomes could not be correlated with radiographic findings, and our recommendation is to continue placing the graft as anatomically as possible. LEVEL OF EVIDENCE Therapeutic Level IV . See Instructions for Authors for a complete description of levels of evidence.