Anthropometric and Radiologic Measurements of Coracoid Dimensions and Clinical Implications in an Indian Population

Comparing the Anatomical Landmarks Versus the Coracoid-Based Landmarks Techniques for Coracoclavicular Stabilization After High-Grade Acromioclavicular Injury: A Biomechanical Study

BACKGROUND

In acute high-grade acromioclavicular (AC) joint injuries, the aim of treatment is robust reduction and stabilization of the joint. The anatomical landmarks method is most commonly used for stabilization, but loss of reduction often occurs because of the suture tunnels.

PURPOSE/HYPOTHESIS

The purpose was to evaluate and compare the stability of coracoclavicular (CC) stabilization using the anatomical landmarks and coracoid-based landmarks techniques in treating a high-grade AC joint injury. It was hypothesized that stabilization using coracoid-based landmarks would provide better stability.

STUDY DESIGN

Controlled laboratory study.

METHODS

Twenty fresh-frozen cadaveric shoulders (8 male and 2 female pairs) were randomized into 2 operative technique groups: 10 shoulders in the anatomical landmarks group and 10 shoulders in the coracoid-based landmarks group. The CC ligaments and AC capsule were cut at the midlevel, and CC stabilization and AC capsule repair were performed. For the anatomical landmarks technique, two 2.5-mm clavicular tunnels were created at 25 and 45 mm from the AC joint, while for the coracoid-based landmarks technique, two 2.5-mm clavicular tunnels were drilled using the medial and lateral borders of the coracoid base to choose the tunnel sites. Before injury creation and after stabilization, each shoulder underwent a loading force of 70 N in the superior and anteroposterior directions, and the displacement distance and stiffness were compared between the 2 techniques using the paired t test.

RESULTS

The mean difference in displacement before and after stabilization was higher in the anatomical landmarks technique than the coracoid-based landmarks technique (1.82 ± 3.52 vs -0.18 ± 4.78 mm in the superior direction and 7.47 ± 9.35 vs 1.76 ± 3.91 mm in the anteroposterior direction), but none of the differences in displacement or stiffness were statistically significant between the groups.

CONCLUSION

No significant biomechanical differences in displacement or stiffness were seen between the anatomical landmarks technique and the coracoid-based landmarks technique.

CLINICAL RELEVANCE

Either stabilization technique can be utilized for repair of the CC ligaments in an acute AC injury setting.

Effect of Preoperative MRI Coracoid Dimensions on Postoperative Outcomes of Latarjet Treatment for Anterior Shoulder Instability

Background:

Preoperative coracoid dimensions may affect the size of the bone graft transferred to the glenoid rim and thus the postoperative outcomes of Latarjet coracoid transfer.

Purpose:

To determine the effect of coracoid length and width as measured on preoperative magnetic resonance imaging (MRI) on outcomes after Latarjet treatment of anterior shoulder instability.

Study Design:

Cohort study; Level of evidence, 3.

Methods:

Included were patients who underwent primary Latarjet surgery between 2009 and 2019 and had preoperative MRI scans and minimum 2-year postoperative outcomes. Longitudinal coracoid length was measured on axial MRI sequences as the distance from the coracoclavicular ligament insertion to the distal tip. Comparisons were made between shorter and longer coracoids and between narrower and wider coracoids. The outcomes of interest were recurrent instability, reoperation, complications, return to sport (RTS), and American Shoulder and Elbow Surgeons (ASES) score. Independent-samples t test, Mann-Whitney test, chi-square test, and Fisher exact test were used to compare outcomes between groups, and univariate correlation coefficients were calculated to evaluate the relationships between demographics and coracoid dimensions.

Results:

Overall, 56 patients were included (mean age, 28.4 years). The mean ± SD coracoid length was 21.6 ± 2.4 mm and width 10.0 ± 1.0 mm. Relative to patients with a longer coracoid (≥22 mm; n = 26), patients with a shorter coracoid (<22 mm; n = 30) had similar rates of recurrent instability (shorter vs longer; 6.7% vs 3.8%), complications (10.0% vs 15.4%), reoperation (3.3% vs 7.7%), and RTS (76.5% vs 58.8%) and similar postoperative ASES scores (85.0 vs 81.6) ( P ≥ .05 for all). Likewise, relative to patients with a wider coracoid (≥10 mm; n = 27), patients with a narrower coracoid (<10 mm; n = 29) had similar prevalences of recurrent instability (narrower vs wider; 6.9% vs 3.7%), complications (17.2% vs 7.4%), reoperation (3.5% vs 7.4%), and RTS (66.7% vs 68.4%) and similar postoperative ASES scores (87.1 vs 80.0) ( P ≥ .05 for all).

Conclusion:

Patients undergoing Latarjet coracoid transfer had similar postoperative outcomes regardless of preoperative coracoid dimensions. These findings should be confirmed in a larger cohort before further clinical recommendations are made.

Open Classic Latarjet Procedure Performed Using Freehand Technique-Surgical Technique and Outcome

INTRODUCTION

Latarjet procedure is commonly performed for recurrent anterior shoulder instability with glenoid side bone loss. Classic Latarjet procedure can be performed using specially designed drill guides, jigs, or by freehand technique. Here we have described a technical note on classic Latarjet procedure performed with freehand technique utilizing simple rulers and caliper. The functional and radiological outcomes of our patients have also been analysed.

MATERIAL AND METHODS

149 open classic Latarjet procedures were performed using our technique between March 2015 and July 2018. The mean age of the patients was 32.95 years (Range 22-59 years). The functional outcome of the patients was measured using Western Ontario Shoulder Instability (WOSI) and Oxford Shoulder Instability Score (OSIS) at 2 years of follow-up. Screw and graft positioning were studied in 24 consecutive patients with a postoperative computed tomography (CT) scan.

RESULTS

There was no incidence of recurrent subluxation or dislocation post-surgery. Mean OSIS score increased from 15.63 ± 3.20 preoperatively to 42.44 ± 3.88 postoperatively (p value < 0.05). WOSI score decreased significantly from 62.54% ± 8.24 to 10.26 ± 6.33 postoperatively at 2-year follow-up (p value < 0.05). Postoperative CT scan also showed satisfactory screw placement in all patients.

CONCLUSION

Open Latarjet procedure performed using freehand technique provides good functional and radiological outcomes in patients with recurrent anterior shoulder instability with glenoid side bone loss.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s43465-021-00385-7.

Computed Tomography-Based Preoperative Planning Provides a Pathology and Morphology-Specific Approach to Glenohumeral Instability With Bone Loss

PURPOSE

To use computed tomography (CT) to determine a reproducible method of coracoid measurement to compare the ability of the classic Latarjet technique and the congruent arc modification (CAM) to restore native glenoid diameter and to develop a preoperative planning algorithm for glenoid restoration with a goal of achieving an on-track shoulder.

METHODS

Coracoid dimensions were measured on multiplanar reconstructed shoulder CT scans of patients aged 18 to 45 years obtained between December 1, 2019, and March 13, 2020. Patients were excluded if CT demonstrated osteophyte formation, glenoid dysplasia, coracoid fracture, or tumor. The proportion of glenoid diameter able to be restored using classic Latarjet technique and CAM were calculated. A treatment algorithm was proposed considering the amount of bone loss present and coracoid dimensions.

RESULTS

Coracoid dimensions of 117 consecutive patients were measured and varied considerably (length: 17.5-31.8 mm, width: 9.1-20.5 mm, thickness: 6.1-15.7 mm). While most patients had harvestable coracoid length ≥20 mm (male: 96.3% vs female: 94.4%, P = .65), only 27.8% of female patients had coracoid thickness ≥10 mm. When comparing Latarjet techniques, there was no difference in the proportion of patients in whom 30% glenoid diameter could be fully restored, but CAM was able to restore at least 35% in more male and female patients (98.8% vs 79.0% and 100% vs 61.1%, respectively, P = .00001). Intra- and inter-rater reliability was excellent ( intraclass correlation coefficient ≥0.950 for all dimensions).

CONCLUSIONS

We describe a reliable method of measuring coracoid dimensions for preoperative planning of glenoid restoration. The classic Latarjet technique reliably restores the glenoid anteroposterior diameter with bone loss of up to 30%. The majority of female patients have coracoid thickness <10 mm, which may increase the risk of graft fracture when using CAM. The decision to use the classic Latarjet technique or CAM considers each individual's glenoid and coracoid dimensions with a goal of achieving an on-track shoulder.

CLINICAL RELEVANCE

Our reliable method of coracoid measurement demonstrated the differing abilities of the classic Latarjet and CAM to restore the native glenoid diameter. An evidence-based algorithm using these measurements was developed to assist in preoperative planning for glenohumeral instability in the setting of bone loss, with a goal of achieving an on-track shoulder. Alternative techniques may be considered if an on-track shoulder cannot be achieved with Latarjet.

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.