Graft Position, Healing, and Resorption in Anterior Glenohumeral Instability: A Comparison of 4 Glenoid Augmentation Techniques

Abstract

Background: The success of glenoid augmentation procedures depends on accurate placement and healing of the graft to the glenoid. Different glenoid augmentation techniques have been described, but no comparative studies between them exist.

Purpose: To assess the bone graft position, healing, and resorption in a group of patients treated with 1 of 4 procedures: arthroscopic anterior bone-block procedure using either (1) fresh-frozen iliac crest allograft or (2) iliac crest autograft, (3) open Latarjet, or (4) arthroscopic Latarjet.

Study design: Cohort study; Level of evidence, 3.

Methods: A total of 40 patients (87.5% men; mean age, 29.5 ± 7.9 years) were included, with 10 patients in each of the procedure groups. The graft position in the axial and sagittal planes was assessed on postoperative computed tomography (CT). Graft healing and resorption were assessed in a second CT scan performed 1 year postoperatively. Qualitative variables were compared between the 4 procedures using the chi-square test, and quantitative variables were compared with the Student t test or Mann-Whitney U test.

Results: No differences were found between the procedures in the axial or sagittal position. The healing rate was significantly lower in the allograft bone-block group (20%) compared with the autograft bone-block (80%), open Latarjet (90%), and arthroscopic Latarjet (90%) groups (P < .001). Graft resorption developed in 17 of 40 (42.5%) cases overall. Osteolysis occurred in 100% of cases in the allograft bone-block group compared with 50% in the autograft group, 20% in the open Latarjet group, and 0% in the arthroscopic Latarjet group (P < .001). The glenoid surface area on 1-year CT scan was significantly lower in the allograft bone-block group compared with the autograft bone-block, open Latarjet, and arthroscopic Latarjet groups (P < .001).

Conclusion: Arthroscopic bone-block, open Latarjet, and arthroscopic Latarjet procedures provided accurate bone graft positioning. However, very high rates of osteolysis and nonunion were observed in the iliac crest fresh-frozen allograft bone-block procedure when compared with the other procedures.

Keywords: Latarjet procedure; anterior shoulder instability; arthroscopic bone block; glenoid bone loss.

Figure 1.

Axial position evaluation on computed tomography. A circle along the glenoid rim was drawn, and the distance between the tip of the graft and the circle was measured. (A) Mildly medialized graft. (B) Slightly lateralized graft.

Figure 2.

Sagittal position evaluation of the bone-block procedure on computed tomography. The percentage of coverage was obtained using the formula (A/B) × 100, where A is the amount of glenoid defect covered by the graft and B is the length of the bone defect. (A) Coverage >90%. (B) More than 10% of the bone defect is uncovered.

Figure 3.

Sagittal position evaluation of the Latarjet procedure on computed tomography. The percentage of graft below the glenoid equator (dotted line) was obtained using the formula (A/B) × 100, where A is the length of the graft and B is the amount of graft above the equator.

Figure 4.

Healing evaluation on axial computed tomography. (A) A healed graft. (B) No bony bridges are observed; thus, the graft was considered unhealed.

Figure 5.

For osteolysis evaluation, graft volume was obtained on computed tomography. (A and B) The contour of the bone graft was manually defined in the axial plane using the close polygon tool in different heights. (C) The entire volume (in cm³) was automatically generated using 3-dimensional reconstruction software.

Figure 6.

The glenoid surface area, A, and residual glenoid bone loss, B, were measured on computed tomography according to the Pico method. (A) Residual bone loss is observed. (B) The glenoid surface area is fully restored.

Figure 7.

Mean glenoid surface area preoperatively, postoperatively, and at the final follow-up.