Graft osteolysis and recurrent instability after the Latarjet procedure performed with bioabsorbable screw fixation

HYPOTHESIS AND BACKGROUND

The Latarjet procedure is a reliable treatment of recurrent anterior shoulder instability. The coracoid process is usually fixed with metallic screws; however, these can lead to irritation and the necessity for hardware removal and also can produce artifacts on imaging studies. The use of resorbable screws could avoid these complications. The purpose of this study was to assess the clinical results of the Latarjet procedure performed with bioabsorbable screws in addition to healing of the graft and resorption of the screws.

METHODS

In 2009, we performed a prospective study (case series,

LEVEL OF EVIDENCE

IV) of 11 patients (12 shoulders) who underwent a Latarjet procedure fixed with resorbable screws. Each patient was observed clinically and had a computed tomography scan at 3 months and 2 years of follow-up.

RESULTS

Every graft healed at 3-month follow-up. At 2-year follow-up, 4 patients had at least one instability episode, and one underwent a revision surgery. Three of these 4 patients were unhappy or disappointed. The Walch-Duplay score was excellent or good for 7 shoulders and medium or poor for 5. Screw resorption appeared complete in every case. No drill hole enlargement was observed. Every drill hole was partially filled with bone. Of 12 shoulders, 8 (66.67%) were associated with a severe osteolysis and an almost complete disappearance of the graft.

CONCLUSION

Coracoid graft osteolysis, previously reported after the Latarjet procedure, appears to be exacerbated with a risk of complete disappearance of the graft when the procedure is performed with the bioabsorbable screws used in this study.

Three-dimensional volume measurement of coracoid graft osteolysis after arthroscopic Latarjet procedure

BACKGROUND AND HYPOTHESIS

The Latarjet procedure has been shown to be a reliable method to prevent recurrent anterior shoulder instability. Coracoid bone graft osteolysis is a potential catastrophic complication and can lead to recurrent instability. The purpose of our study is to present a novel quantitative method to measure the amount of coracoid bone osteolysis using 3-dimensional (3D) computed tomography (CT) scan imaging.

MATERIALS AND METHODS

This is a prospective study with 15 patients (16 shoulders) who underwent an arthroscopic Latarjet procedure. Three-dimensional CT scans were obtained at 6 weeks and 6 months. Using volumetric analysis, we quantified the amount of bone loss using our described method. Interobserver reliability and intraobserver reliability were calculated.

RESULTS

On the basis of our new volumetric analysis of the arthroscopic Latarjet procedure using 3D CT scans, we found that the superior half of the coracoid bone graft undergoes a significant amount of osteolysis at 6 months postoperatively. The interobserver reliability and intraobserver reliability were excellent.

DISCUSSION

This study presents a reproducible method to quantify and compare coracoid bone graft osteolysis after an arthroscopic Latarjet procedure. We also developed a description system that may be used for comparison studies. To our knowledge, this is the first method that quantifies the amount of coracoid bone graft osteolysis using more accurate 3D CT scanning.

CONCLUSION

The 3D analysis we propose is a valid method to measure the amount of coracoid bone graft osteolysis after an arthroscopic Latarjet procedure. Our description system may guide the surgeon regarding possible revision surgery when faced with significant osteolysis of the coracoid bone graft.

Coracoid graft union: a quantitative assessment by computed tomography in primary and revision Latarjet procedure

BACKGROUND

The goal of the Latarjet procedure is restoration of shoulder stability enabled by accurate graft positioning and union. This study aimed to establish a reproducible method of quantitatively assessing coracoid graft osseous union percentage (OUP) using computed tomography (CT) scans and to determine the effect of other factors on the OUP.

MATERIALS AND METHODS

Postoperative CT scans of 41 consecutive patients treated with the open Latarjet procedure (37% primary, 63% revision) for anterior glenohumeral instability were analyzed for the OUP, position of the graft, and screw type and angle. Two musculoskeletal radiologists independently examined the images 2 times, and intraobserver and interobserver reliability was calculated using intraclass correlation coefficient (ICC).

RESULTS

Mean OUP was 66% (range, 0%-94%) using quantitate methods, with good intraobserver reliability (ICC = 0.795) and interobserver reliability (ICC = 0.797). Nonunion and significant graft resorption was found in 2 patients. No significant difference was found in the mean OUP in the primary (63%) vs. revision Latarjet procedure (67%). Grafts were flush in 39%, medial in 36%, and lateral in 8%. The medial and neutral graft position was associated with slightly higher OUP (72% and 69%) compared with lateral (65%). OUP was higher when the superior screw angle was less than 17° and the inferior screw angle was less than 24°. This difference did not reach statistical significance. Screw type was not associated with significant difference in OUP.

CONCLUSION

Quantitative assessment of osseous union of the graft using a reproducible method that we introduced showed similar OUP in the primary and revision Latarjet procedure.

Accuracy of Coracoid Bone Graft Placement: Open versus Arthroscopic Latarjet

Purpose  The aim of this study was to compare the accuracy of the coracoid bone graft placement with the open Latarjet-Patte and arthroscopic Latarjet (arthro-Latarjet) procedures in the treatment of anterior instability of the shoulder.

Methods  Forty-six patients affected by anterior shoulder instability were divided into two groups. In group A ( n  = 25), patients were operated by arthroscopic Latarjet (arthro-Latarjet) procedure and in group B ( n  = 21), patients were operated by open Latarjet-Patte procedure. Instrumental investigation was based on three-dimensional computed tomography (3D-CT) at a minimum 1-year follow-up. Graft placement and integration, divergence and posterior protrusion of the screws, and glenohumeral osteoarthritis were considered as outcomes. Statistical analysis was performed with chi-square or Fisher's exact test. Significance was set at p  < 0.05.

Results  Positioning of the coracoid graft proved to be optimal in 76% (19/25) of patients of group A and in 100% (21/21) of patients of group B (Fisher's exact test, p  = 0.025). Screw placement with respect to the glenoid surface showed a posterior divergence in 44% (11/25) of patients in group A and in 24% (5/21) of patients in group B ( p  = 0.15). Posterior protrusion of screw was observed in 76% (19/25) of patients in group A and 71.4% (15/21) of patients in group B ( p  = 0.73). Graft integration was present in 76% (19/25) of patients in group A and 85.7% (18/21) of patients in group B (Fisher's exact test, p  = 0.48). Mild signs of glenohumeral osteoarthritis were observed in 12% (3/25) of patients in group A and 28.6% (6/21) of patients in group B (Fisher's exact test, p  = 0.26).

Conclusion  Patients operated with open Latarjet-Patte procedure showed better results than those of the arthro-Latarjet group in reference to the positioning of the graft on the coronal plane ( p  = 0.025). No significant differences between the groups were observed for graft integration, divergence of the screws, posterior protrusion of the screws, and osteoarthritis.

Level of Evidence  Level II, nonrandomized prospective comparative study.

Proximal-medial part in the coracoid graft demonstrates the most evident stress shielding following the Latarjet procedure: a simulation study using the 3-dimensional finite element method

BACKGROUND

Although the osteolysis of the coracoid graft is frequently observed after the Latarjet procedure particularly in its proximal part, its pathomechanism is not well understood.

METHODS

Three-dimensional finite element glenohumeral joint models were developed using CT-DICOM data of 10 normal shoulders. A 25% bony defect was created on the anterior glenoid rim, and the coracoid process was transferred flush with the glenoid cartilage using 2 half-threaded screws. In the hanging arm as well as in the 90° abducted positions, a compressive load (50 N) was applied to the greater tuberosity toward the center of the glenoid and a tensile force (20 N) was applied to the coracoid tip along the direction of the conjoint tendon. Next, elastic analysis was performed, and the distribution patterns of the equivalent stress as well as the maximum principal stress were compared among 4 parts (proximal/distal and medial/lateral) of the coracoid graft.

RESULTS

Both the equivalent stress and the maximum principal stress were reduced in the proximal half of the coracoid graft. A high stress concentration was observed in the lateral aspect of the coracoid graft particularly in the 90° abducted position. The proximal-medial part demonstrated the lowest equivalent stress as well as the maximum principal stress for both arm positions, which were significantly lower than those in the distal 2 parts.

CONCLUSION

In the Latarjet procedure, the proximal-medial part of the coracoid graft demonstrated the most evident stress shielding, which may play an important role in postoperative osteolysis.

Intra-articular biomechanical environment following modified Bristow and Latarjet procedures in shoulders with large glenoid defects: relationship with postoperative complications

BACKGROUND

Although coracoid transfers including the modified Bristow and Latarjet procedures are widely used to treat anterior shoulder instability, the influence of the choice of procedure on the biomechanical outcomes is not well characterized. We aimed to clarify the intra-articular stress distribution following these 2 procedures using 3-dimensional finite-element analysis and to investigate the role of stress distribution in the pathophysiology of postoperative complications.

METHODS

Overall, 6 male patients aged 17-47 years with unilateral anterior shoulder instability were recruited. Computed tomographic digital imaging and communications in medicine (CT-DICOM) data of the contralateral (healthy) shoulder of each patient was obtained and used for developing the 3-dimensional normal glenohumeral joint model. A 25% bony defect was created in the anterior glenoid rim where the coracoid process was transferred in the standing and lying-down positions to create the Bristow and Latarjet models, respectively. The arm position was set as 0° or 90° abduction. The Young moduli of the humerus and scapula were calculated using CT data, and set as 35.0 MPa and 113.8 GPa for the articular cartilage and inserted screw, respectively. A compressive load (50 N) was applied to the greater tuberosity toward the center of the glenoid, and a tensile load (20 N) was applied to the tip of the coracoid in the direction of conjoint tendon. Elastic analysis was used to determine the equivalent stress distribution.

RESULTS

A significant reduction in mean equivalent stress was observed within the glenoid cartilage for both models (P = .031); however, a new stress concentration appeared within the grafted coracoid-facing region of the humeral-head cartilage in both models. The proximal half of the coracoid graft exhibited lower equivalent stress than the distal half in 5 of the 6 Latarjet models, whereas the proximal half showed higher equivalent stress than the distal half in all 6 Bristow models. High stress concentration was identified at the midpoint of the inserted screw in Bristow models.

DISCUSSION AND CONCLUSIONS

Intra-articular stress distribution may explain the different rates of postoperative complications associated with the modified Bristow and Latarjet procedures. New stress concentration within the humeral-head cartilage might contribute to the development of glenohumeral osteoarthritis following both procedures. Stress shielding in the proximal part of the coracoid graft might contribute to osteolysis following the Latarjet procedure. Surgeons should be aware of the risk of breakage of the inserted screw following the modified Bristow procedure.

Influence of Graft Positioning during the Latarjet Procedure on Shoulder Stability and Articular Contact Pressure: Computational Analysis of the Bone Block Effect

The Latarjet procedure is the most popular surgical procedure to treat anterior glenohumeral (GH) instability in the presence of large anterior glenoid bone defects. Even though the placement of the bone graft has a considerable influence on its efficacy, no clear indications exist for the best graft position. The aim of this study was to investigate the influence of the medial-lateral positioning of the bone graft on the contact mechanics and GH stability due to the bone block effect. Four finite element (FE) models of a GH joint, with a 20% glenoid bone defect, treated by the Latarjet procedure were developed. The FE models differed in the medial-lateral positioning of the bone graft, ranging from a flush position to a 4.5 mm lateral position with respect to the flush position. All graft placement options were evaluated for two separate shoulder positions. Anterior GH instability was simulated by translating the humeral head in the anterior direction, under a permanent compressive force, until the peak translation force was reached. Joint stability was computed as the ratio between the shear and the compressive components of the force. The lateralization of the bone graft increased GH stability due to the bone block effect after a 3 mm lateralization with respect to the flush position. The increase in GH stability was associated with a concerning increase in peak contact pressure due to the incongruous contact between the articulating surfaces. The sensitivity of the contact pressures to the medial-lateral positioning of the bone graft suggests a trade-off between GH stability due to the bone block effect and the risk of osteoarthritis, especially considering that an accurate and consistent placement of the bone graft is difficult in vivo.

Functional Outcome of Open Latarjet Procedure in Non-Athletic Middle-Aged Patients

Introduction:

The movement and steadiness of the shoulder joint is due to both the dynamic and static stabilisers. Recurrent anterior shoulder instability is common due to the Bankart lesion or the Hill Sachs lesion. The bone loss and soft tissue failure due to these lesions causing instability is well compensated by Latarjet procedure which acts by triple blocking effect of the bone graft, the sling effect of the conjoint tendon of subscapularis and the ligament of the coracoacromial ligament stump.

Materials and methods:

Middle-aged patients with recurrent anterior shoulder dislocation and a mid-range instability on clinical assessment with an isolated glenoid bone loss of 20% or Bankart lesion with engaging Hill Sachs lesion were selected for the study. The surgical procedure included a subscapularis split to expose the glenoid. The coracoid graft harvested was prefixed with Kirschner wires and placed flush over the glenoid ensuring no medial or lateral overhang and fixed with 4.0mm cancellous screws with the washer. The functional outcome was measured with the ROWE score and ASES score and the movements were evaluated.

Results:

A total of 24 patients fulfilled the inclusion criteria. Post-operatively at final follow-up, the mean ROWE score was 97.08 ±8.45 and the mean ASES score was 94.4±9.10. One patient had screw breakage as a complication and another had restriction of movement which was managed with physiotherapy.

Conclusion:

Open Latarjet is an effective procedure for recurrent anterior shoulder instability in non-athletic middle-aged patients as a excellent functional outcome was achieved with this technique. We therefore recommend open Latarjet as an alternative to arthroscopic treatment in developing countries where patient affordability and the availability of the resources are the issues.