Preoperative CT planning of screw length in arthroscopic Latarjet

Arthroscopic Latarjet procedure: current concepts and surgical techniques

The Latarjet procedure is a surgical procedure that can effectively restore glenohumeral stability, especially in patients with anterior shoulder instability and glenoid bone loss. Many studies have shown comparable clinical outcomes between patients undergoing the arthroscopic Latarjet procedure and those undergoing traditional open methods or other glenohumeral joint stabilization procedures. However, the arthroscopic Latarjet procedure is a challenging technique due to the unfamiliar portal placements, proximity of neurovascular structures, and serious postoperative complications. The arthroscopic Latarjet procedure has not yet been widely applied, and a clear understanding of the anatomical structure and the precise methods is required prior to operation performance. Satisfactory clinical outcomes can be achieved by thorough preoperative planning and proper implant fixation methods.

Arthroscopic Latarjet procedure and suture-button fixation: can we predict nonunion early?

BACKGROUND

The arthroscopic Latarjet procedure is a technically challenging technique that provides well-known results. The first series reported fixation with screws. An alternative fixation technique has been proposed, using a button, to improve the reproducibility and to decrease the complications due to screws. The first reports using this fixation technique have yielded comparable rates of fusion. The objective of this study was to assess the fusion rate and bone modifications with this type of fixation.

METHODS

Two hundred sixteen patients were included in this prospective study. An arthroscopic Latarjet procedure, fixed with 1 button according to the Smith & Nephew technique, was performed by a single surgeon for the treatment of anterior instability. The radiographic protocol consisted of computed tomography scans at 3, 12, and 24 weeks postoperatively. We measured the coronal and sagittal positions of the bone block, distance between the bone block and the glenoid, diameter of the glenoid tunnel, fusion rate, and time to fusion.

RESULTS

The position was deemed flush in 92.6% of cases in the coronal plane and under the equator in 87.5% of cases in the sagittal plane. At last follow-up, we observed 9 cases of nonunion (4%), as well as 18 cases of delayed fusion. The fusion rate was 92% at 3 months and 96% at 6 months. For bone blocks that ultimately healed, the diameter of the glenoid tunnel was <2 mm in 62% of cases at 3 weeks and <1 mm in 90% of cases at 3 months. Conversely, the diameter of this tunnel significantly increased and was >3 mm in all cases of delayed union or nonunion.

CONCLUSION

The described technique achieved a reliable position of the bone block and a very good fusion rate with a new type of fixation. The time to obtain fusion can be lengthy, occurring between the third and sixth months. The diameter of the glenoid tunnel was the best predictive factor for fusion. Widening of the glenoid tunnel diameter >3 mm during the first 3 weeks was the most predictive factor for delayed union or nonunion of the bone block. This finding is probably explained by a sliding effect of the sutures through this tunnel, comparable to the bungee effect in anterior cruciate ligament repair in the knee.

What is the best position for coracoid fixation in the Latarjet procedure?

Hypothesis

Multiple problems and complications associated with Latarjet fixation have been described; thus, this is the first study in the literature to identify the maximum allowed screw clamping force and best fixation screw position for Latarjet surgery.

Methods

A variation of distal and proximal coracoid screw positions with and without a flat washer was evaluated through finite element analysis, at a minimum distance of 3 mm from the edge. A loading progression test was performed until the maximum stress reached a limit imposed by the bone yield. We identified the maximum allowed screw clamping force based on a von Mises and maximum principal stresses failure theory.

Results

When using the flat washer, the cortical bone generally has only space for 1 piece. For this reason, as a primary study, it was observed that when the distal screw was more than 7 mm from the edge, the clamping force supported will be higher than that during the proximal fixation regardless of the proximal location screw. We have found that the best position is 7 mm from the distal edge, with the highest compression of 445 N (7 mm proximal distance, 5 mm distal distance) in due respect to the von Mises failure theory. To get around this lack of space situation, in this study, we have proposed a fixation plate to replace the flat washer. This plate has shown very interesting values when compared to the previously flat washer study, but now, for both screw holes. With those results, we can assure that using a fixation plate like this will ensure surgery safety and higher allowed compression force when clamping the bolts.

Conclusion

The distal screw provided higher tensile strength values when located more than 7 mm from the coracoid edge. The geometry of the coracoid in its distal position supports higher stress loads than in the proximal position. When the flat washer was in the proximal position, the coracoid was submitted with a more distributed and uniform load, preventing localized bone damage as a crush.

Use of Cannulated Screws for Primary Latarjet Procedures

Background

Rapid consolidation of the bone block is paramount for the success of the Latarjet procedure. Noncannulated screws have shown satisfactory long-term bone block fusion, while cannulated screws are challenged with inferior mechanical properties and fusion rates.

Purpose

To report outcomes of the Latarjet procedure using cannulated screws, notably bone block fusion and complication rates at 3 months, as well as clinical scores and return to sports at minimum 2 years postoperatively.

Study Design

Case series; Level of evidence, 4.

Methods

We reviewed the records of 124 consecutive patients (124 shoulders) who underwent primary Latarjet procedures using cannulated screws between 2015 and 2018. All patients underwent clinical examination at 3 months postoperatively, including range of motion and radiographs to assess graft fusion. The Walch-Duplay score, Rowe score, Subjective Shoulder Value, and visual analog scale for pain were collected at a minimum follow-up of 2 years.

Results

Overall, 9 patients (7%) required reoperation: 7 (6%) had screw removal for unexplained residual pain, 1 (0.8%) had lavage for deep infection, and 1 (0.8%) had evacuation to treat a hematoma. Furthermore, 3 patients (2.4%) had recurrent instability, none of whom underwent reoperation. At 3-month follow-up, all 124 shoulders showed complete radiographic graft fusion, and at 40 ± 11 months (mean ± SD; range, 24-64 months), 88% of patients had returned to sport (109/124), the Walch-Duplay score was 86 ± 14, Rowe was 84 ± 15, Subjective Shoulder Value was 88 ± 11, and visual analog scale for pain was 1 ± 1.

Conclusion

The clinical relevance of these findings is that 4.5-mm cannulated screws are safe and effective for primary Latarjet procedures and grant adequate graft healing, with low recurrence of instability and a high rate of return to sports.

Screw Removal Can Resolve Unexplained Anterior Pain Without Recurrence of Shoulder Instability After Open Latarjet Procedures

BACKGROUND

Anterior shoulder instability can be successfully treated using Latarjet procedures, although a small proportion of patients report unexplained pain.

PURPOSE/HYPOTHESIS

The purpose was to report the prevalence and characteristics of patients with unexplained pain without recurrent instability after open Latarjet procedures and to determine whether screw removal can alleviate pain. The hypothesis was that unexplained pain without recurrent instability might be due to soft tissue impingements against the screw heads and that the removal of screws would alleviate or reduce pain.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

We retrospectively reviewed the clinical and radiographic records of 461 consecutive shoulders treated by open Latarjet procedures for anterior instability between 2002 and 2014. Unexplained anterior pain was present in 21 shoulders (4.6%) and treated by screw removal at 29 ± 37 months (mean ± SD). Postoperative assessment at >12 months after screw removal included complications, visual analog scale for pain (pVAS), subjective shoulder value, Rowe score, Walch-Duplay score, and ranges of motion. The study cohort comprised the shoulders of 20 patients (9 women, 11 men) aged 25 ± 6 years (median, 25 years; range, 16-34 years) at screw removal and involved the dominant arm in 13 (62%) shoulders.

RESULTS

Screw removal alleviated pain completely in 14 shoulders (67%; pVAS improvement, 6.4 ± 1.8; median, 6; range, 3-8) and reduced pain in the remaining 7 (33%; pVAS improvement, 2.4 ± 1.4; median, 2; range, 1-5). At 38 ± 23 months after screw removal, 2 recurrences of instability unrelated to screw removal occurred. The subjective shoulder value was 79% ± 22% (median, 90%; range, 0%-95%); Rowe score, 85 ± 20 (median, 95; range, 30-100); and Walch-Duplay score, 82 ± 19 (median, 85; range, 25-100). Mobility improved in active forward elevation (171°± 14°), external rotation with the elbow at the side (61°± 12°), and external rotation with the arm at 90° of abduction (67°± 13°) and especially in internal rotation, with only 2 shoulders (10%) limited to T12 spine segment.

CONCLUSION

The present findings confirm that unexplained anterior pain after Latarjet procedures can be related to the screws used to fix bone blocks, which can safely be alleviated or reduced by screw removal.

Arthroscopic Latarjet Stabilization: Analysis of the Learning Curve in the First 90 Primary Cases: Early Clinical Results and Computed Tomography Evaluation

PURPOSE

To assess the learning curve of arthroscopic Latarjet, evaluating time of surgery, clinical outcomes, complications, revisions, and recurrence.

METHODS

Arthroscopic Latarjet procedures performed from 2011 to 2016 were reviewed. Satisfaction rate, subjective shoulder value, Walch-Duplay, Rowe scores, range of motion, and stability were evaluated on clinical examination. Graft position and fusion were analyzed using computed tomography. All patients were divided into 3 chronological groups.

RESULTS

Ninety patients (3 groups of 30) were available for clinical evaluation (96,8%). The mean follow-up was 23.7 months. Surgical time was significantly (P = .0028) longer in group I (mean 128 minutes, standard deviation [SD] 33.6) when compared with groups II (mean 102 minutes, SD 16.2) and III (mean 108 minutes, SD 21.8). A regression analysis and cumulative sum learning curve analysis showed the surgeon oscillated around mean operative time (112.7 minutes; SD 27.2) after 30 procedures. The number of intraoperative complications was significantly greater (P = .024) in Group I (5 cases; 17%) compared with zero in group II, and 3 (10%) in group III. All 3 cases (3.3%) of recurrence were reported in group I (P = .033). Significantly, 2 of 3 patients with recurrence had intraoperative graft complications (P = .0107). Overall patient satisfaction was evaluated as 92%, SSV 90%, Walch-Duplay and Rowe scores, respectively, 79 and 81 points. Nine revisions (10%) were reported. No significant differences were found between the results and revisions of the 3 chronological groups.

CONCLUSIONS

This study confirms that the arthroscopic Latarjet procedure provides good clinical and radiologic results at short-term follow-up. The surgical time, frequency of complications, and number of hardware problems significantly decreased after the first 30 cases. As such, surgeons should be aware of the elevated potential for complications and recurrence early in the learning curve-serious intraoperative complications are important risk factors for recurrence.

LEVEL OF EVIDENCE

III. Therapeutic study: case-control study.

Intraoperative graft-related complications are a risk factor for recurrence in arthroscopic Latarjet stabilisation

PURPOSE

The goal of this study was to evaluate clinical and radiological outcomes after arthroscopic Latarjet stabilisation in anterior shoulder instability.

METHODS

Ninety-three patients after primary arthroscopic Latarjet stabilisation were reviewed. Satisfaction, subjective shoulder value (SSV), Walch-Duplay and Rowe scores, and range of motion and stability were evaluated on clinical examination. Computed tomography (CT) was used to analyse graft position and fusion.

RESULTS

Ninety patients (96.8%) were available for clinical and 85 for CT evaluation. The mean follow-up was 23.7 months (13-50, SD 7.1) and age at surgery was 26.2 years (16-44, SD 5.6). Intraoperative complications were reported in eight patients (8.9%) and recurrence in three (3.3%). Significantly, two out of three patients with recurrence had intraoperative graft complications (p = 0.0107). Forty-one patients (45.6%) reported the feeling of "subjective return to sport anxiety". External rotation with arm at the side was 59° (10-90°, SD 20) with 15° (0-70°, SD 17) of loss of rotation. These two factors correlated with results the most. Patient satisfaction was evaluated as 92% (40-100, SD 14) and SSV 90% (30-100, SD12). Revision rate after primary surgery was 10%. CT showed graft healing in 81 (95.3%) patients. A graft position between 2 and 5 o'clock was found in 70 (83.4%) patients and flush to the anterior glenoid rim in 34 (40.5%). Osteolysis of the superior part of the graft was found in 55 (64.7%) patients. CT evaluation showed no correlation with clinical results.

CONCLUSION

Arthroscopic Latarjet stabilisation demonstrates satisfactory results in short-term follow-up; however, intraoperative graft-related complications are a risk factor for recurrence. "Subjective return to sport anxiety" and loss of external rotation with the arm at the side are factors worsening the results. Graft position imperfections and osteolysis of the superior part of the graft reported in CT evaluation do not influence the clinical results.

Monocortical fixation of the coracoid in the Latarjet procedure is significantly weaker than bicortical fixation

PURPOSE

A crucial step of the Latarjet procedure is the fixation of the coracoid process onto the glenoid. Multiple problems associated with the fixation have been described, including lesions of the suprascapular nerve due to prominence of the screw or bicortical drilling. The purpose of the present study was to evaluate whether monocortical fixation, without perforating the posterior glenoid cortex, would provide sufficient graft stability.

METHODS

Coracoid transfer was performed in 14 scapula models (Sawbones^®, Composite Scapula, 4th generation). Two groups were assigned: in one group, fixation was achieved with two screws that did not perforate the posterior cortex of the glenoid neck (monocortical fixation), in the other group, fixation was achieved with perforation of the posterior cortex (bicortical fixation). The ultimate failure load and mode of failure were evaluated biomechanically.

RESULTS

Monocortical fixation was a significantly weaker construct than bicortical fixation (median failure load 221 N, interquartile range 211-297 vs. median failure load 423 N, interquartile range 273-497; p = 0.017). Failure was either due to a pullout of the screws from the socket or a fracture of the glenoid. There was no significant difference in the mode of failure between the two groups (n.s.).

CONCLUSION

Monocortical fixation was significantly weaker than bicortical fixation. However, bicortical drilling and overly long screws may jeopardize the suprascapular nerve. Thus, anatomic knowledge about the safe zone at the posterior rim of the glenoid is crucial. Until further research has evaluated, if the inferior stability is clinically relevant, clinicians should be cautious to use a monocortical fixation technique for the coracoid graft.