Biomechanical Comparison of Screw Fixation Versus a Cortical Button and Self-tensioning Suture for the Latarjet Procedure

Sutures, Screws, Buttons, and Anchors: A Review of Current Bone Graft Fixation Devices for Glenoid Bone Loss in the Unstable Shoulder

PURPOSE OF REVIEW

Anterior shoulder instability is associated with concomitant injury to several stabilizing structures of the shoulder, including glenoid bone loss. While instability is most common in young athletes and patients with predisposing conditions of hyperlaxity, recurrent shoulder instability can occur throughout various age ranges and may lead to longer term effects including pain and shoulder arthritis. Glenoid bone loss exceeding certain thresholds is generally treated by glenoid reconstruction via bone block augmentation to adequately stabilize the glenohumeral joint. These procedures increase the width of the articular surface on which the humeral head can translate before dislocation and, based on the procedure performed, provide a sling effect via the conjoined tendon, and increase tension to support the anterior capsule. The purpose of this review is to summarize the available literature regarding bone block fixation techniques.

RECENT DEVELOPMENTS

Various fixation techniques have been utilized to secure bone block transfers. Though screw fixation has traditionally been used for bone block fixation, suture buttons, suture anchors, and all-suture techniques have been utilized in attempts to avoid complications associated with the use of screws. Biomechanical studies report variable force-resistance, displacement, and mode of failure when comparing screw to suture button-based fixation of glenoid bone blocks. Clinical and radiographic studies have shown these novel suture-based techniques to be comparable, and in some cases advantageous, to traditional screw fixation techniques. While screw fixation has long been the standard of care in glenoid bone block procedures, it is associated with high complication rates, leading surgeons to endeavor toward new fixation techniques. In available biomechanical studies, screw fixation has consistently demonstrated high maximal load-to-failure and displacement with cyclic loading. Studies have reported similar clinical and radiographic outcomes in both screw and suture-based fixation methods, with evidence of reduced bone resorption with suture fixation. While suture button fixation is associated with a higher rate of recurrent instability, overall complication rates are low. Future research should address biomechanical shortcomings of suture-based fixation techniques and continue to assess long-term follow-up of patients treated with each fixation method.

Arthroscopic Latarjet Versus Arthroscopic Free Bone Block Procedures for Anterior Shoulder Instability: A Proportional Meta-analysis Comparing Recurrence, Complication, and Reoperation Rates

BACKGROUND

Several arthroscopic glenoid bone augmentation techniques have been introduced to treat patients affected by anterior shoulder instability associated with critical bone loss. The efficacy of the different arthroscopic bony procedures has not been compared yet.

PURPOSE

To compare the recurrence, complication, and reoperation rates of the arthroscopic Latarjet (AL) and arthroscopic free bone block (ABB) procedures for anterior shoulder instability.

STUDY DESIGN

Meta-analysis and systematic review; Level of evidence, 4.

METHODS

A systematic search was conducted in MEDLINE/PubMed, Web of Science, and Embase to identify clinical studies reporting the outcomes of the AL and ABB procedures. The following search phrases were used: "Arthroscopic" AND "Bone Block" OR "Bone Graft," and "Arthroscopic" AND "Glenoid Augmentation" OR "Glenoid Reconstruction," and "Arthroscopic" AND "Latarjet" OR "Coracoid Graft" OR "Coracoid Transfer." Exclusion criteria were <24 months of minimum follow-up, sample size <10 cases, revision after previous glenoid bone grafting, epilepsy, and multidirectional instability. Data regarding the study design, patient characteristics, surgical technique, and outcomes were extracted and analyzed. A proportional meta-analysis was conducted to compare the complication, recurrence, and reoperation rates between the 2 groups. Multiple subgroup analyses were performed to analyze the incidence of each complication and assess the weight of different fixation methods (in the whole cohort) or different graft types (in the ABB group). The modified Coleman Methodology Score was used to assess the risk of bias.

RESULTS

Of 5010 potentially relevant studies, 18 studies regarding the AL procedure (908 cases) and 15 studies regarding the ABB procedure (469 cases) were included. The 2 groups were comparable in age (P = .07), sex (P = .14), glenoid bone loss (P = .14), number of preoperative dislocations (P = .62), proportion of primary and revision procedures (P = .95), length of follow-up (P = .81), modified Coleman Methodology Score (P = .21), and level of evidence (P = .49). There was no difference in the recurrence (P = .88), reoperation (P = .79), and complication (P = .08) rates. The subgroup analyses showed a higher rate of hardware-related complications for screw fixation compared with flexible fixation (P = .01).

CONCLUSION

The AL and ABB procedures had similar recurrence, reoperation, and complication rates. Screw fixation of the bone graft was related to an increased risk of complications compared with flexible fixation.

REGISTRATION

CRD42022368153 (PROSPERO).

Editorial Commentary: Suture Button Fixation for the Latarjet Procedure Is Superior to Screw Fixation

An increasing body of evidence suggests that suture button fixation is comparable with screw fixation in Latarjet and potentially associated with reduced graft resorption. Suture button fixation may facilitate performing the Latarjet procedure, particularly when done in an arthroscopic manner. The use of suture button fixation technique theoretically facilitates improved positioning of the graft on the glenoid, as it frees the surgeon from the potential of the soft-tissue envelope to impact positioning of the graft, which can occur with screw-based guides. The bone graft can be shuttled into an optimal position and then tensioned with relative ease in comparison with screw-based techniques. Suture button fixation results in lower complication rates compared with screw fixation; almost one third of the screw fixation complications are hardware-related, and screw fixation results in a high rate of hardware removal. Moreover, the arthroscopic Latarjet suture button literature is published by experienced surgeons. Arthroscopic Latarjet has a significant learning curve, reducing the translatability of studies that report superior findings with any one technique. The generalizability of results reminds us that evidence-based medicine should be practiced through the lens of not only patient preferences, but also through an honest appraisal of a surgeon's own ability.

Arthroscopic Autologous Iliac Bone Grafting With Double-Row Elastic Fixation and Double Antirotating Anchors for Recurrent Anterior Shoulder Dislocation With Massive Glenoid Bone Defect

The management of recurrent anterior shoulder dislocations with massive glenoid bone defects typically involves arthroscopic intervention. Autologous iliac bone grafting with double-row elastic fixation reportedly yields excellent outcomes. In this article, we introduce a specialized technique for iliac bone grafting that uses double-row elastic fixation and double antirotating anchors. Implementation of this technique prevents the occurrence of iliac graft rotation.

Inlay structure can improve bone graft stability in the Bristow procedure

BACKGROUND

Compared with the Latarjet procedure, the Bristow procedure has a lower screw-related complication rate but poor bone healing. A modified Inlay Bristow procedure has been reported to significantly improve the bone healing rate, but the biomechanical mechanism is unclear. The aim of this study was to evaluate the biomechanical stability of the bone graft between a modified Inlay Bristow procedure and the classic Bristow procedure.

METHODS

Sixteen left scapula models (Sawbones, Composite Scapula, and fourth generation) were randomly divided into 2 groups (8:8). The bone graft in the first group was fixed with a 3.5 mm screw using the Inlay structure. The bone graft in the second group was fixed with a 3.5 mm screw via the traditional method. The maximum cyclic displacement, ultimate failure load and stiffness were evaluated biomechanically. The failure type was recorded for each model.

RESULTS

Cyclic loading tests demonstrated that the maximum cyclic displacement of the Inlay procedure was significantly smaller (P = .001) than that of the classic procedure. The Inlay Bristow technique resulted in a significantly higher (P = .024) ultimate failure load than the classic Bristow technique. The stiffness of the classic group was 19.17 ± 4.01 N/mm and that of the inlay group was 22.34 ± 5.35 N/mm (P = .232). Failure was mainly due to bone graft fractures through the drill hole or glenoid bone fractures.

CONCLUSION

Inlay Bristow fixation of the bone graft in a Sawbones model provides significantly stronger fixation and better time point zero stability than classic Bristow fixation, suggesting a higher likelihood of graft union.

Primary bone graft stability after Latarjet surgery: biomechanical evaluation of a fixation technique with metal-free all-suture cerclage vs. cortical screws

BACKGROUND

To reduce hardware-related complications in coracoid graft fixation to the anterior aspect of the glenoid, a metal-free Latarjet technique was recently introduced. The aim of this study was to compare the primary stability of a classic Latarjet procedure with 2 metal screws to a novel metal-free, all-suture cerclage method. It is hypothesized that fixation of the coracoid graft with 2 malleolar screws will provide higher primary stability compared with an all-suture cerclage technique.

METHODS

This biomechanical in vitro study was conducted on 12 fresh-frozen cadaveric shoulders (6 matched pairs) with a mean donor age of 80 years (range, 67-89 years). Coracoid graft fixation was performed using a recently introduced all-suture cerclage technique (group A) or a classic Latarjet technique with two 4.5-mm malleolar screws (group B). The conjoint tendon was loaded with a static force of 10 N to simulate the sling effect. Graft loading with a probe head consisted of 6 ascending load levels (10-50 N, 10-100 N, 10-150 N, 10-200 N, 10-250 N, and 10-300 N) with 100 cycles each at 1 Hz. Relative motion of the bone graft to the glenoid was measured using an optic 3-dimensional system.

RESULTS

While loading the conjoint tendon with 10 N, no difference in mean displacement of the bone-graft was found between both groups (P = .144). During cyclic loading, a significant difference in relative displacement for both groups was already detected in load level 1 (group A: 2398.8 μm vs. group B: 125.7 μm; P = .024), and this trend continued with the following load levels (P < .05).

DISCUSSION AND CONCLUSION

The study demonstrated that the innovative metal-free, all-suture cerclage fixation technique results in higher micromotion than the classic coracoid graft fixation with 2 malleolar screws. According to the present biomechanical investigation, shoulders treated with a metal-free all-suture cerclage technique might need adapted rehabilitation protocols to protect the construct and allow for graft healing.

Surgical considerations for glenoid bone loss in anterior glenohumeral instability: a narrative review

PURPOSE

Treatment algorithms may consider many factors like glenoid and humeral bone loss, or scores such as the instability severity index score (ISIS). As most studies only evaluate a part of these factors, there is still no evidence-based consensus estalished. Our study aims to summarize the surgical options for treatment of glenoid bone loss (GBL) in anterior shoulder instability.

METHODS

Based on the current available literature, surgical options including Bankart repair and glenoid bone augmentation should be considered while taking into consideration the degree of bone loss which has been divided into < 10%, 10-20% and > 20%.

RESULTS

There are many new techniques evolving including arthroscopic anatomic glenoid reconstruction with bone blocks.

CONCLUSION

Future long-term outcome studies and randomized controlled trials comparing established techniques will be needed for new evidence-based treatment algorithms.

Suspensory fixation for bone transfer procedures in shoulder instability is superior to screws in an angled construct: a biomechanical analysis

Background

The Latarjet procedure is a common bony augmentation procedure for anterior shoulder instability. Historically, screw fixation is used to secure the coracoid graft to the anterior glenoid surface; however, malpositioning of the graft leads to oblique screw insertion that contributes to complications. Suture buttons (SBs) are a more recent fixation technique that have not been studied alongside standard screw fixation in the context of biomechanical models of angulated fixation. This study aims to compare the biomechanical strength of single and double, screw and SB fixation at various levels of angulation.

Methods

Testing was performed using polyurethane models from Sawbones. The graft piece was secured with screw fixation (Arthrex, Naples, FL, USA) or suspensory button (ABS Tightrope, Arthrex, Naples, FL, USA). Single or double constructs of screws and SBs were affixed at 0°, 15°, and 30° angles to the face of the glenoid component. An aluminum testing jig held the samples securely while a materials testing system applied loads. Five constructs were used for each condition and assessed load to failure testing.

Results

For single fixation constructs, suspensory buttons were 60% stronger than screws at 0° (P < .001), and 52% stronger at 15° (P = .004); however, at 30°, both were comparable (P = .180). Interestingly, single suspensory button at 15° was equivalent to a single screw at 0° (P = .310). For double fixation, suspensory buttons (DT) were 32% stronger than screws at 0° (P < .001) and 35% stronger than screws at 15° (P < .001). Both double fixation methods were comparable at 30° (P = .061). Suspensory buttons at 15° and 30° were equivalent to double screws at 0 (P = .280) and 15° (P = .772), respectively.

Conclusion

These measurements indicate that the suspensory button has a significantly higher load to failure capacity over the screw fixation technique, perpendicularly and with up to 15° of angulation. These analyses also indicate that the suspensory button fixation offers superior strength even when positioned more obliquely than the screw fixation. Therefore, suspensory button fixation may confer more strength while offering greater margin for error when positioning the graft.

Isolated Primary Latarjet Procedures for Anterior Shoulder Instability Results in High Rates of Graft Resorption and Glenohumeral Degenerative Changes With Low Rates of Failure at a Minimum 2-Year Follow-Up: A Systematic Review

PURPOSE

To evaluate the incidence of postoperative complications after an isolated primary Latarjet procedure for anterior shoulder instability at a minimum 2-year follow-up.

METHODS

A systematic review was performed in accordance with 2020 PRISMA guidelines. EMBASE, Scopus, and PubMed databases were queried from database inception through September 2022. The literature search was limited to human clinical studies reporting on postoperative complications and adverse events after a primary Latarjet procedure with a minimum 2-year follow-up. Risk of bias was measured using the Newcastle-Ottawa Scale.

RESULTS

Twenty-two studies, consisting of 1,797 patients (n = 1,816 shoulders), with a mean age of 24 years were identified. The overall postoperative complication rate ranged from 0% to 25.7%, with the most common complication being persistent shoulder pain (range: 0%-25.7%). Radiological changes included graft resorption (range: 7.5%-100%) and glenohumeral degenerative changes (range: 0%-52.5%). Recurrent instability following surgery was documented in 0% to 35% of shoulders, while the incidence of bone block fractures ranged from 0% to 6% of cases. Postoperative nonunion, infection, and hematomas had a reported incidence rate ranging from 0% to 16.7%, 0% to 2.6%, and 0% to 4.4%, respectively. Overall, 0% to 7.5% of surgeries were reported failures, and 0% to 11.1% of shoulders required reoperation, with a revision rate ranging from 0% to 7.7%.

CONCLUSIONS

The incidence of complications following the primary Latarjet procedure for shoulder instability was variable, ranging from 0% to 25.7%. High rates of graft resorption, degenerative changes, and nonunion were present while failure and revision rates remained low at a minimum 2-year follow-up.

LEVEL OF EVIDENCE

Level III, systematic review of Level I-III studies.

Biomechanical Evaluation of the 2 Different Levels of Coracoid Graft Positions in the Latarjet Procedure for Anterior Shoulder Instability

Background

In the Latarjet procedure, the ideal placement of the coracoid graft in the medial-lateral position is flush with the anterior glenoid rim. However, the ideal position of the graft in the superior-inferior position (sagittal plane) for restoring glenohumeral joint stability is still controversial.

Purpose

To compare coracoid graft clockface positions between the traditional 3 to 5 o'clock and a more inferior (for the right shoulder) 4 to 6 o'clock with regard to glenohumeral joint stability in the Latarjet procedure.

Study Design

Controlled laboratory study.

Methods

A total of 10 fresh-frozen cadaveric shoulders were tested in a dynamic, custom-built robotic shoulder model. Each shoulder was loaded with a 50-N compressive load while an 80-N force was applied in the anteroinferior axes at 90° of abduction and 60° of shoulder external rotation. Four conditions were tested: (1) intact, (2) 6-mm glenoid bone loss (GBL), (3) Latarjet procedure fixed at 3- to 5-o'clock position, and (4) Latarjet procedure fixed at 4- to 6-o'clock position. The stability ratio (SR) and degree of lateral humeral displacement (LHD) were recorded. A 1-factor random-intercepts linear mixed-effects model and Tukey method were used for statistical analysis.

Results

Compared with the intact state (1.77 ± 0.11), the SR was significantly lower after creating a 6-mm GBL (1.14 ± 0.61, P = .009), with no significant difference in SR after Latarjet 3 to 5 o'clock (1.51 ± 0.70, P = .51) or 4 to 6 o'clock (1.55 ± 0.68, P = .52). Compared with the intact state (6.48 ± 2.24 mm), LHD decreased significantly after GBL (3.16 ± 1.56 mm, P < .001) and Latarjet 4 to 6 o'clock (5.48 ± 3.39 mm, P < .001). Displacement decreased significantly after Latarjet 3 to 5 o'clock (4.78 ± 2.50 mm, P = .04) compared with the intact state but not after Latarjet 4 to 6 o'clock (P = .71).

Conclusion

The Latarjet procedure in both coracoid graft positions (3-5 and 4-6 o'clock) restored the SR to the values measured in the intact state. A more inferior graft position (fixed at 4-6 o'clock) may improve shoulder biomechanics, but additional work is needed to establish clinical relevance.

Clinical Relevance

An inferior coracoid graft fixation, the 4- to 6-o'clock position, may benefit in restoring normal shoulder biomechanics after the Latarjet procedure.

Editorial Commentary: Both Bristow and Latarjet Procedures Result in Low Rates of Recurrent Shoulder Instability Despite Potential for Bone Resorption and Lack of Graft Healing

Anterior shoulder instability surgery has evolved over the decades, including both anatomic and nonanatomic repairs and reconstructions. Surgeons are continually advancing their skills and performing more of these procedures using arthroscopic as opposed to open techniques in patients with and without glenoid bone loss. However, there is a steep learning curve and increased technical demands when performing these procedures arthroscopically. Despite high success rates, bone graft resorption or lack of healing after Latarjet and Bristow procedures is well documented, and it is possible that patients develop enough scarring that their shoulders remain stable. Osteoarthritis after these nonanatomic procedures can occur making shoulder arthroplasty and reconstruction technically more challenging because of scarring and the altered anatomy. It remains to be seen whether these arthroscopic techniques as opposed to open surgery lessen the scarring and thus the technical demands of shoulder reconstruction in the small subset of patients who unfortunately develop symptomatic shoulder osteoarthritis. Therefore, in my practice, these techniques are carefully chosen for select patients. My indications for use of the Bristow procedure as a primary procedure for anterior shoulder instability are in patients who perform mixed martial arts fighting and high-level wrestlers without significant glenoid or humeral bone loss. My indications for the Latarjet procedure are in patients with chronic anterior instability and associated anterior glenoid bone loss 15% to 30%, off-track Hill-Sachs lesions, and revision surgery, particularly in high-demand contact and collision athletes. These 2 arthroscopic procedures, despite being nonanatomic, provide surgeons with excellent treatment options for those difficult patients with anterior shoulder instability. Despite high success rates with these arthroscopic procedures, patients should be counseled on the risks of graft resorption, graft nonunion, and possible shoulder osteoarthritis. The appropriate indications for these arthroscopic procedures can enhance the successful outcomes for high-risk patients with shoulder instability while also considering the possible long-term impacts of altering shoulder anatomy and scarring in the rare patient who develops shoulder osteoarthritis.

Clinical Outcomes, Union Rates, and Complications of Screw Versus Button Fixation in the Bristow-Latarjet Procedure for Anterior Shoulder Instability: A Systematic Review and Meta-Analysis

Background

The Latarjet procedure is a common procedure for treating critical glenoid bone loss in anterior shoulder instability. Implants such as the screw and cortical button are widely used. The aim of this study was to compare studies on screw versus button fixation techniques in the Bristow-Latarjet procedure for anterior shoulder instability in terms of clinical outcomes, union rates, and complications.

Methods

The PubMed, Scopus, and Embase databases were searched to find comparative studies that reported outcomes of using screw versus button fixation in the Bristow-Latarjet procedure following the 2020 Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) guidelines. Studies that directly compared the screw and button fixation techniques and provided postoperative patient-reported outcomes, union rates, or complications were included. The Methodology Index for Non-Randomized Research (MINORS) criteria were used to assess the quality of the included studies. Odds ratios (ORs) were calculated for dichotomous outcomes whereas mean differences were calculated for continuous outcomes.

Results

Five articles included a total of 877 shoulders. All five studies had level 3 evidence. There was no statistically significant difference between the two techniques using the Walch-Duplay score, visual analog scale for pain, American Shoulder and Elbow Surgeons score, Simple Shoulder Test, range of motion, and graft union rates. However, the button fixation technique had statistically significantly higher recurrence rates than the screw fixation technique (OR, 0.24; 95% confidence interval, 0.10-0.58; p = 0.001).

Conclusions

The screw fixation technique had statistically significantly lower recurrence rates than the button fixation technique. However, there was no significant difference between screw and button fixation techniques regarding postoperative patient-reported outcomes, range of motion, graft union rates, nerve injury rates, infection rates, and reoperation rates.

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.

Free Bone Block Procedures for Glenoid Reconstruction in Anterior Shoulder Instability

Advances in the understanding and management of bone loss in shoulder instability have led to the development of free bone block techniques as an alternative to the Latarjet procedure. These techniques have been proposed as a theoretically safer option to Latarjet, and there is growing clinical enthusiasm in their use. The purpose of this article was to contextualize the utilization of free bone block procedures in the current treatment paradigm of anterior shoulder instability and to review the history and common types of bone autograft (eg, iliac crest, distal clavicle, scapular spine) and allograft (eg, distal tibia, preshaped blocks) techniques and approaches, as well as their clinical effectiveness and safety.

A Systematic Review of Screw and Suture Button Glenoid Augmentation Constructs

Background

Glenohumeral dislocations often lead to glenoid bone loss and recurrent instability, warranting bony augmentation. While numerous biomechanical studies have investigated fixation methods to secure a graft to the glenoid, a review of available constructs has yet to be performed.

Purpose

To synthesize the literature and compare the biomechanics of screw and suture button constructs for anterior glenoid bony augmentation.

Study Design

Systematic review.

Methods

A systematic review was conducted in accordance with the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. There were 2 independent reviewers who performed a literature search using the PubMed, Embase, and Google Scholar databases of studies published between 1950 and 2020. Studies were included that compared the biomechanical outcomes of fixation for the treatment of anterior shoulder instability with glenoid bone loss.

Results

Overall, 13 of the 363 studies screened met the inclusion criteria. The included studies measured the biomechanical strength of screws or suture buttons on a cadaveric or synthetic Latarjet construct. Screws and suture buttons were biomechanically similar, as both constructs exhibited comparable loads at failure and final displacement. Screw type (diameter, threading, or composition) did not significantly affect construct strength, and double-screw fixation was superior to single-screw fixation. Additionally, 2 screws augmented with a small plate had a higher load at failure than screws that were not augmented. Unicortical double-screw fixation was inferior to bicortical double-screw fixation, although construct strength did not significantly decrease if 1 of these screws was unicortical. Further, 2 screws inserted at 15° off axis experienced significantly higher graft displacement and lower ultimate failure loads than those inserted at 0° parallel to the glenoid.

Conclusion

Suture buttons provided comparable strength to screws and offer an effective alternative to reduce screw-related complications. Augmentation with a small plate may clinically enhance construct strength and decrease complications through the dispersion of force loads over a greater surface area. Differences in screw type did not appear to alter construct strength, provided that screws were placed parallel to the articular surface and were bicortical.

Primary Stability and Bone Contact Loading Evaluation of Suture and Screw based Coracoid Graft Fixation for Anterior Glenoid Bone Loss

BACKGROUND

Reconstruction techniques for anterior glenoid bone loss have seen a trend from screws to suture-based fixations. However, comparative biomechanical data, including primary fixation and glenoid-graft contact pressure mapping, are limited.

HYPOTHESIS

Suture-based bone block cerclage (BBC) and suspensory suture button (SB) techniques provide similar primary fixation and cyclic stability to double-screw fixation but with higher contact loading at the bony interface.

STUDY DESIGN

Controlled laboratory study.

METHODS

In total, 60 cadaveric scapulae were prepared to simulate anterior glenoid bone loss with coracoid autograft reconstruction. Graft fixation was performed with 3 different techniques: (1) an interconnected all-suture BBC, (2) 2 SB suspensions, and (3) 2 screws. Initial compression was analyzed during primary fixation. Cyclic peak loading with 50 N and 100 N over 250 cycles at 1 Hz was performed with a constant valley load of 25 N. Optical recording and pressure foils allowed for spatial bone block tracking and contact pressure mapping at the glenoid-graft interface. Load-to-failure testing was performed at a rate of 1.5 mm/s with ultimate load and stiffness measured.

RESULTS

Initial graft compression was higher with screw fixation (141 ± 5 N) compared with suture-based fixations (P < .001), with BBC fixation providing significantly higher compression than SB fixation (116 ± 7 N vs. 91 ± 5 N; P < .001). Spatial bone block migration and ultimate failure load were similar between the BBC and screw groups. The SB group showed significantly increased bone block translation (3.1 ± 1.0 mm; P≤ .014) and rotation (2.5°± 1.4°; P≤ .025) and significantly lower ultimate failure load (180 ± 53 N) compared with the BBC (P = .046) and screw (P = .002) groups. Both suture-based fixations provided significantly increased graft-glenoid contact loading with higher pressure amplitudes (P≤ .032) and contact pressure after cyclic loading (+13%; SB: P = .007; BBC: P = .004) compared with screw fixation.

CONCLUSION

Both SB and interconnected cerclage fixation improved dynamic contact loading compared with screw fixation in a biomechanical glenoid bone loss model. Cerclage fixation was biomechanically comparable with screw fixation but with a greater variability. SB fixation showed significantly lower primary fixation strength and greater bone block rotation and migration.

CLINICAL RELEVANCE

Suture-based bone block fixations improved graft-glenoid contact loading, but the overall clinical consequence on healing remains unclear.

Remodeling process and clinical outcomes following all-arthroscopic modified Eden-Hybinette procedure using iliac crest autograft and 1-tunnel double Endobutton fixation system

BACKGROUND

Arthroscopically modified Eden-Hybinette procedures for glenohumeral stabilization have been used for a long time. With the advancement of arthroscopic techniques and the development of sophisticated instruments, a double Endobutton fixation system has been used clinically to secure bone graft to the glenoid rim placed through a specifically designed guide. The purpose of this report was to evaluate clinical outcomes and serial glenoid remodeling process following all-arthroscopic anatomical glenoid reconstruction using autologous iliac crest bone grafting technique through 1-tunnel fixation.

METHODS

Forty-six patients with recurrent anterior dislocations and significant glenoid defects greater than 20% underwent arthroscopic surgery with a modified Eden-Hybinette technique. Instead of firm fixation, autologous iliac bone graft was fixed to the glenoid by double Endobutton fixation system through 1-tunnel placed in the glenoid surface. Follow-up examinations were performed at 3, 6, 12, and 24 months. The patients were followed up for a minimum of two years using the Rowe score, the Constant score, the Subjective Shoulder Value, and the Walch-Duplay score; patient satisfaction with the procedure outcome was also rated. Graft positions, healing, and absorption were evaluated postoperatively with computed tomography imaging.

RESULTS

At a mean follow-up of 28 months, all patients were satisfied and had a stable shoulder. The Constant score improved from 82.9 to 88.9 points (P ＜ .001), the Rowe score, improved from 25.3 to 89.1 points (P < .001), the Subjective Shoulder Value improved from 31% to 87% (P < .001), and the Walch-Duplay score improved from 52.5 to 85.7 points (P ＜ .001). One donor-site fracture occurred during the follow-up period. All grafts were well-positioned and achieved optimal bone healing with zero excessive absorption. The preoperative glenoid surface (72.6% ± 4.5%) increased significantly immediately after surgery to 116.5% ± 9.6% (P ＜ .001). After a physiological remodeling process, the glenoid surface remained significantly increased at the last follow-up (99.2% ± 7.1%) (P ＜ .001). The glenoid surface area appeared to decrease serially when compared between the first 6 months and 12 months postoperatively, while there was no significant interval change between 12 and 24 months postoperatively.

CONCLUSION

Patient outcomes were satisfactory following the all-arthroscopic modified Eden-Hybinette procedure using an autologous iliac crest grafting technique through one-tunnel fixation system with double Endobutton. Graft absorption mostly occurred on the edge and outside the ''best-fit'' circle of the glenoid. Glenoid remodeling occurred within the first year after all-arthroscopic glenoid reconstruction with an auto iliac bone graft.

Acromion and Distal Clavicle Grafts for Arthroscopic Glenoid Reconstruction

BACKGROUND

We intended to determine if an acromion or distal clavicle bone graft could restore large glenoid defects using two novel, screw-free graft fixation techniques.

METHODS

Twenty-four sawbone shoulder models were divided into four groups (n = 6 per group) according to fixation technique and bone graft: (1) modified buckle-down technique with clavicle graft, (2) modified buckle-down technique with acromion graft, (3) cross-link technique with acromion graft, (4) cross-link technique with clavicle graft. Testing was performed sequentially in (1) intact models, (2) after creation of a 30% by-width glenoid defect and (3) after repair. The shoulder joint was translated anteriorly, and glenohumeral contact pressures and load were measured to quantify the biomechanical stability.

RESULTS

Maximum contact pressures were restored to 42-56% of intact glenoid using acromion and clavicle grafts with novel fixation techniques. Acromion grafts attained higher maximum contact pressures than clavicle grafts in all groups. Peak translational forces increased by 171-368% after all repairs.

CONCLUSIONS

This controlled laboratory study on sawbone models found that both the acromion and distal clavicle are suitable autologous bone graft options for treating large anterior glenoid defects, having appropriate dimensions and contours for reconstructing the glenoid arc. The modified buckle-down and cross-link techniques are two graft fixation techniques that restore stability to the shoulder joint upon repairing a large glenoid defect and are advantageous in being screw-free and simple to execute.

Radiological and Histological Analyses of Nonrigid Versus Rigid Fixation for Free Bone Block Procedures in a Rabbit Model of Glenoid Defects

BACKGROUND

Nonrigid fixation techniques have been recently introduced in free bone block (FBB) procedures to treat substantial glenoid bone loss in patients with anterior shoulder instability. However, the radiological and histological effectiveness of nonrigid fixation versus conventional rigid fixation have not been comprehensively understood in vivo.

PURPOSE

To (1) explore the radiological and histological characteristics of nonrigid fixation for FBB procedures in a rabbit model of glenoid defects and (2) further compare them with those of conventional rigid fixation.

STUDY DESIGN

Controlled laboratory study.

METHODS

Unilateral shoulder glenoid defects were created in 36 mature New Zealand White rabbits, of which 24 underwent FBB procedures using allogenic iliac crest bone and were randomly divided into rigid fixation (RF) and nonrigid fixation (N-RF) groups, with the remaining divided into 2 control groups: 6 with sham surgery for glenoid defects (GD group) and 6 native glenoids (normal group). In the RF and N-RF groups, 6 rabbits were sacrificed at 6 or 12 weeks postoperatively for radiological and histological analyses of the reconstructed glenoid, and all rabbits in the GD and normal groups were sacrificed at 12 weeks. The radiological glenoid morphology was evaluated via micro-computed tomography. Moreover, the graft-glenoid healing and graft remodeling processes were determined using histological staining.

RESULTS

At 6 weeks, both the N-RF and RF groups had similarly improved radiological axial radian and en face area of the glenoid compared with the GD group, but the N-RF group showed superiority in restoration of the glenoid radian and area compared with the RF group at 12 weeks, with the native glenoid as the baseline. Histologically, the bone graft in both groups was substantively integrated into the deficient glenoid neck at 6 and 12 weeks, showing similar osseous healing processes at the graft-glenoid junction. Moreover, the bone graft histologically presented similar regenerated vascular density, total graft bone, and integrated graft bone in both groups. In contrast, the N-RF group had a different remodeling profile on radiological and histological analyses regarding regional bone resorption, mineralization, and fibrous tissue replacement during osseointegration.

CONCLUSION

Compared with rigid fixation, nonrigid fixation resulted in superior reconstructed glenoid morphology radiologically and similar graft-glenoid osseous healing histologically, showing different graft remodeling profiles of regional bone resorption, mineralization, and fibrous tissue replacement.

CLINICAL RELEVANCE

The nonrigid fixation technique can be feasible for FBB procedures to treat glenoid bone loss in anterior shoulder instability. More clinical evidence is required to determine its pros and cons compared with conventional rigid fixation.

Arthroscopically Assisted Anterior Bone Block for Shoulder Instability

Background:

Shoulder instability is a common complaint, with treatment depending on the severity of the bony defect. Advancements in arthroscopic techniques have allowed for a less invasive surgery with decreased postoperative pain, improved graft placement, and better visualization.

Indications:

Large bony defects of the glenoid require bone block augmentation to reduce recurrent instability. In this presentation, arthroscopically assisted anterior bone block was performed with a distal tibial allograft to address recurrent anterior shoulder instability with a large glenoid defect.

Technique Description:

The patient is placed in a lateral decubitus position. Standard arthroscopic portals are made. The bone block is fashioned from a distal tibial allograft. Using a guide, drill holes are placed in the bone block. The guide is inserted from the posterior portal and placed parallel to the joint surface. Using drill sleeves, superior and inferior screw holes are drilled and a metal cannula is left in place to allow for shuttling of suture. Two anchors are placed on the glenoid to allow for capsule labral junction to be brought up to the graft once the graft is in place. The bone block is delivered through a dilated anterior portal and reduced. The sutures are tensioned. A button is placed on each set of looped sutures, a Nice knot is placed into each, and a tensioning device is tensioned. Once compression is achieved, knots are tied to perform final fixation over the buttons. A suture passing device is used to grab inferior capsule and labrum to the priorly placed anchor on the inferior glenoid and tied.

Results:

Arthroscopically assisted anterior bone block for shoulder instability has been demonstrated to have similar clinical and radiographic outcomes when compared with open treatment. However, arthroscopically assisted Latarjet has been shown to have decreased soft tissue disruption and possible improvements in graft placement.

Discussion/Conclusion:

Arthroscopically assisted anterior bone block is a technically demanding surgery but has been shown to have similar outcomes when compared with open treatment. In this video, we demonstrate an arthroscopically assisted anterior bone block for recurrent anterior shoulder instability.

Patient Consent Disclosure Statement:

The author(s) attests that consent has been obtained from any patient(s) appearing in this publication. If the individual may be identifiable, the author(s) has included a statement of release or other written form of approval from the patient(s) with this submission for publication.

Biomechanical Strength of Screw Versus Suture Button Fixation in the Latarjet Procedure: A Cadaver Study

We compared the strength of screw vs suture button fixation in the Latarjet procedure for shoulder dislocation through biomechanical testing in a cadaver model. Cadavers were assigned randomly to receive screw or suture button fixation (both groups, n=5). The anteroposterior radius of the glenoid was measured, and a bony defect was created on the anteroinferior rim of the glenoid, equal to 25% of the width of the anteroposterior radius of the glenoid surface. The coracoid process was transferred into the newly created bony defect of the glenoid and fixed with two 3.5-mm partially threaded cannulated screws or 2 surgical buttons. All samples underwent tensile testing in the anteroinferior direction. Statistical analysis was performed to compare mean forces at failure between groups (alpha=.05). The mean force at failure was higher in the screw group (295 N; range, 103-534 N) than in the suture button group (133 N; range, 74-270 N) (P=.045). We found no difference between groups in ability to withstand a force of 150 N, which is the reported mean daily force threshold borne by the shoulder (P=.52). Screw fixation withstood a higher failure load than suture button fixation, indicating that screw fixation is a biomechanically superior option in the Latarjet procedure. The fixation methods did not differ in their ability to withstand the mean force borne by the shoulder during activities of daily living; thus, suture button fixation should be considered as an option in the Latarjet procedure. [Orthopedics. 2022;45(6):e321-e325.].

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.

Clinical and Radiologic Outcomes of All-Arthroscopic Latarjet Procedure With Modified Suture Button Fixation: Excellent Bone Healing With a Low Complication Rate

PURPOSE

To investigate the clinical outcomes and radiologic evaluation of an all-arthroscopic Latarjet procedure with modified button fixation.

METHODS

Patients who received all-arthroscopic Latarjet procedure with modified suture button fixation between September 2015 to September 2016 were retrospectively reviewed. Indications for surgery were recurrent anterior shoulder dislocation with any 1 of these 3 conditions: glenoid defect >15%, contact-sport athlete, or failure after Bankart repair. Inclusion criteria included cases who received this surgery. Clinical outcomes were evaluated by University of California Los Angeles, ASES and Rowe score with a minimal follow-up of 3 years. Radiologic assessment on 3D computed tomography scan was performed preoperatively and postoperatively at different time points. Complications were also recorded.

RESULTS

A total of 30 patients were eventually included in this study. The mean follow-up time was 38.0 ± 2.5 months. There were 25 patients who performed contact sports. Of them, 10 patients were without glenoid defect >15% or failed Bankart repair. The remaining 20 patients had glenoid defect >15%, including 2 failed Bankart cases. Ten patients had glenoid defect < 13.5%, and the rest 20 patients had > 13.5%. UCLA, American Shoulder and Elbow Surgeons, and Rowe score significantly improved during follow-up, and the improvement exceeded MCID for all patients. No severe complications were noted. In total, 86.7% of the graft positioning was measured as flush and 13.3% as medial. The bone union rate was 96.7% at 3 months postoperatively and at final follow-up. The remodeling process for the restoration of the normal anatomy of the lower part of glenoid was noted.

CONCLUSIONS

All-arthroscopic Latarjet with modified suture button fixation can achieve stable fixation of the coracoid, good clinical outcomes (all patients with improvement exceeding MCID), low complications rate. Furthermore, the bone remodeling process contributes to the recovery of the normal anatomy of anteroinferior glenoid.

STUDY DESIGN

Case series; Level of evidence, 4.

Tensioning device increases coracoid bone block healing rates in arthroscopic Latarjet procedure with suture-button fixation

BACKGROUND

There is growing interest in using suture buttons for coracoid fixation to avoid the complications associated with screws during the Latarjet procedure. However, achieving bone block healing is critical for successful shoulder stabilization and return to sport. The purpose of this study was to assess and compare the healing rates and positioning of the coracoid bone block fixed with cortical suture buttons that were either manually tensioned (using a knot pusher) or mechanically tensioned (using a tensioning device) during arthroscopic Latarjet procedures.

METHODS

This prospective, nonrandomized, comparative study enrolled 69 consecutive patients (mean age, 27 years) who underwent an arthroscopic guided Latarjet procedure with suture-button fixation. Hand tensioning was performed in the first 34 shoulders, whereas the next 35 shoulders underwent mechanical tensioning. Twelve patients (17%) had a history of failed Bankart stabilization. The characteristics of the patients in each group in terms of age, sex, type of sport, bone loss, number of previous failed surgical procedures, smoking, and length of follow-up were comparable. Intraoperatively, the tensioning device was set at 100 N successively 3 times until complete immobilization of the bone block was confirmed, as assessed with a probe. The primary outcome measure was coracoid bone block union and position on computed tomography scan images at 6 months' follow-up. Secondary outcome measures included functional outcome scores, shoulder stability, return to sports, and complications at last follow-up.

RESULTS

Overall, the rate of bone block healing was 74% (25 of 34 patients) in the hand-tensioning group and 94% (33 of 35 patients) in the mechanical tensioning group (P = .043). Smoking was an independent risk factor associated with nonunion (P < .001) in each group. Patient age, size of the preoperative glenoid bone defect (<20% or >20%), and a history of surgery were not found to have any influence. The tensioning modality did not affect the bone block position, which was subequatorial in 92% of the cases and flush with the glenoid rim in 92%. At a mean of 34 months of follow-up (range, 24-62 months), 96% of the patients (65 of 69) had a stable shoulder and 87% returned to sports. At final follow-up, no significant difference in clinical scores was noted between the groups; no neurologic or hardware complications were observed.

CONCLUSION

Mechanical tensioning achieves significantly higher healing rates than hand tensioning during the arthroscopic Latarjet procedure with suture-button fixation. The use of a suture-tensioning device is a key step to the suture-button fixation technique during arthroscopic Latarjet procedures. By making the suture-button construct rigid, the tensioning device transforms the initially flexible suture into a "rigid fixation", similar to a bolt (or a rivet).

Arthroscopic Technique for Distal Tibial Allograft Bone Augmentation With Suture Anchor Fixation for Anterior Shoulder Instability

Recurrent instability associated with glenoid bone loss is a commonly encountered problem after anterior shoulder dislocation. Surgical management with bony augmentation can be achieved with several allograft or autograft options. Fixation strategies also vary, including screw, suture button, or suture anchor fixation. Concerns exist regarding screw fixation because of the technical difficulty of a medial portal establishment, as well as the potential for graft osteolysis. Suture button fixation for osteochondral graft fixation has been previously described. However, no description of graft fixation using suture anchors exists. We describe an arthroscopic technique for glenoid augmentation using distal tibial allograft with suture anchor fixation.

A review of bone grafting techniques for glenoid reconstruction

BACKGROUND

Traumatic anterior shoulder dislocations can cause bony defects of the anterior glenoid rim and are often associated with recurrent shoulder instability. For large glenoid defects of 20-30% without a mobile bony fragment, glenoid reconstruction with bone grafts is often recommended. This review describes two broad categories of glenoid reconstruction procedures found in literature: coracoid transfers involving the Bristow and Latarjet procedures, and free bone grafting techniques.

METHODS

An electronic search of MEDLINE and PubMed was conducted to find original articles that described glenoid reconstruction techniques or modifications to existing techniques.

RESULTS

Coracoid transfers involve the Bristow and Latarjet procedures. Modifications to these procedures such as arthroscopic execution, method of graft attachment and orientation have been described. Free bone grafts have been obtained from the iliac crest, distal tibia, acromion, distal clavicle and femoral condyle.

CONCLUSION

Both coracoid transfers and free bone grafting procedures are options for reconstructing large bony defects of the anterior glenoid rim and have had similar clinical outcomes. Free bone grafts may offer greater flexibility in graft shaping and choice of graft size depending on the bone stock chosen. Novel developments tend towards minimising invasiveness using arthroscopic approaches and examining alternative non-rigid graft fixation techniques.

Clinical and Radiographic Outcomes After Arthroscopic Inlay Bristow Surgery With Screw Versus Suture Button Fixation: A Comparative Study of 117 Patients With 3.3-Year Follow-up

Background:

Some studies have advocated the use of suture button fixation during Bristow-Latarjet surgery to reduce complications associated with screw fixation. However, data comparing these fixation methods are relatively incomplete.

Purpose:

To investigate the efficacy of modified arthroscopic Bristow-Latarjet surgery and compare the clinical and radiographic outcomes using screw versus suture button fixation.

Study Design:

Cohort study; Level of evidence, 3.

Methods:

We evaluated 136 patients with traumatic anterior shoulder instability who underwent the modified arthroscopic Bristow-Latarjet surgery between June 2015 and February 2018. Of these patients, 117 who met the inclusion criteria were enrolled at a mean follow-up of 3.3 ± 0.7 years. Shoulders were separated into 2 groups based on fixation technique: screw fixation (group A; n = 63) or suture button fixation (group B; n = 54). Computed tomography imaging findings and clinical results were assessed preoperatively; immediately after operation; and postoperatively at 3 months, 6 months, 1 year, and final follow-up.

Results:

There were no significant differences between the groups in terms of postoperative clinical scores, the level of return to sports, range of motion, graft position, or reoperation rates. Bone healing was observed in 97.4% of the cases overall (114/117), with 98.4% bone union in group A and 96.3% in group B at final follow-up. Bone absorption was more common in group A (n = 30; 47.6%) compared with group B (n = 10; 18.5%) (P = .003). There were no hardware-related complications in group B, compared with 7.9% of patients in group A (P = .034). One patient in group B had a recurrent dislocation due to an unexpected event, and there were no recurrent dislocations in group A.

Conclusion:

After the modified arthroscopic Bristow-Latarjet procedure, both suture button and screw fixation methods demonstrated high bony healing rates and low risk of recurrence. Less coracoid graft resorption and no hardware-related complications were seen with suture button fixation.

Factors affecting biomechanical strength of Latarjet constructs: A systematic review and meta-regression

BACKGROUND

The Latarjet procedure reduces recurrent glenohumeral instability but has potential hardware and graft complications. The procedure has been modified to use various screw types as well as suture buttons. Biomechanical studies have evaluated the effect of these implants on construct strength. With varying results it is unclear whether there is an optimal implant to use.

METHODS

We conducted a systematic review of human cadaveric biomechanical studies evaluating Latarjet ultimate failure load. Two independent reviewers screened articles and included them after full text review. Additional factors including implants used, graft orientation, cortices engaged, drill diameter, and screw characteristics were recorded. Meta-regression was performed on the 145 specimens from eight studies that met inclusion criteria.

RESULTS

Screw fixation resulted in a 396.8 N (95% CI, 149.8-643.7) N higher ultimate failure load against shear stresses than suture buttons (p = 0.002). There were no differences between implants for ultimate failure load against tensile forces. Tensile strength was significantly affected by drill diameter with each millimeter of increase reducing the mean ultimate failure load by 127.4 N (95% CI, 41.2-213.6) N (p = 0.004).

CONCLUSIONS

These results suggest that using screw fixation and minimizing drill diameter can obtain the maximum ultimate failure load against both shear and tensile forces in a Latarjet construct.

Arthroscopic Latarjet: 2 or 4 Cortical Buttons for Coracoid Fixation? A Case-Control Comparative Study

BACKGROUND

While 2 screws are traditionally used for coracoid bone block fixation, no gold standard technique has yet been established when using cortical buttons.

PURPOSE

To compare anatomic and clinical outcomes of the arthroscopic Latarjet procedure using either 2 or 4 buttons for coracoid bone block fixation.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

A total of 23 patients with 4-button fixation (group 4B) were matched for age at surgery, sex, and follow-up to 46 patients who had 2-button fixation (group 2B). All patients underwent guided arthroscopic Latarjet (using coracoid and glenoid guides), and a tensioning device was used to rigidify the suture button construct and get intraoperative bone block compression. The primary outcome was assessment of bone block positioning and healing using computed tomography scans performed at 2 weeks and at least 6 months after surgery. The mean ± standard deviation follow-up was 49 ± 7 months (range, 24-64 months).

RESULTS

The bone block healing rate was similar in both groups: 91% in group 4B versus 95.5% in group 2B. The transferred coracoid was flush to the glenoid surface in 21 patients (91%) in group 4B and 44 patients (96%) in group 2B (P = .6); it was under the equator in 22 patients (96%) in group 4B and 44 patients (96%) in group 2B (P≥ .99). There was no secondary bone block displacement; the rate of bone block resorption was similar between the groups: 28% in group 4B and 23% in group 2B (P = .71). Patient-reported outcomes, return to sports, and satisfaction were also similar between the groups. The operating time was significantly longer in group 4B (95 vs 75 minutes; P = .009).

CONCLUSION

A 4-button fixation technique did not demonstrate any anatomic or clinical advantages when compared with a 2-button fixation technique, while making the procedure more complex and lengthening the operating time by 20 minutes. A 2-button fixation is simple, safe, and sufficient to solidly fix the transferred coracoid bone block. The use of drill guides allows accurate graft placement, while the use of a tensioning device to rigidify the suture button construct provides high rates of bone block healing with both techniques (>90%).

A biomechanical comparison of steel screws versus PLLA and magnesium screws for the Latarjet procedure

INTRODUCTION

The fixation of the coracoid process onto the glenoid is an important step of the Latarjet procedure, and implant-associated complications are a relevant and severe problem. This study compares the fixation strength and failure mode of two biodegradable materials with stainless-steel screws.

METHODS

24 Fresh-frozen cadaveric scapulae were divided into three groups of equal size and received a coracoid transfer. Cadavers were matched according to their bone mineral density (BMD). In group 1, small-fragment screws made of stainless steel were used. In the second group, magnesium screws were used, and in the third group, screws consisted of polylactic acid (PLLA). A continuously increasing sinusoidal cyclic compression force was applied until failure occurred, which was defined as graft displacement relative to its initial position of more than 5 mm.

RESULTS

At 5-mm displacement, the axial force values showed a mean of 374 ± 92 N (range 219-479 N) in group 1 (steel). The force values in group 2 (magnesium) had a mean of 299 ± 57 N (range 190-357 N). In group 3 (PLLA), failure occurred at 231 ± 83 N (range 109-355 N). The difference between group 1 (steel) and group 2 (magnesium) was not statistically significant (P = 0.212), while the difference between group 1 (steel) and group 3 (PLLA) was significant (P = 0.005).

CONCLUSION

Stainless-Steel screws showed the highest stability. However, all three screw types showed axial force values of more than 200 N. Stainless steel screws and PLLA screws showed screw cut-out as the most common failure mode, while magnesium screws showed screw breakage in the majority of cases.

EVIDENCE

Controlled laboratory study.

Arthroscopic "Double-Inlay" Eden-Hybinette Procedure with Modified Suture Button Fixation for the Revision of Failed Bristow-Latarjet

Bristow-Latarjet procedure has been widely regarded as a reliable and satisfactory operation for recurrent anterior glenohumeral instability, especially for patients with significant glenoid bone loss or high sports demand. Once failed, however, the subsequent revision surgery could be challenging. Eden-Hybinette procedure is the most common operation for revision of failed Bristow-Latarjet. It can perfectly restore the bone defect of the failed Bristow-Latarjet by harvesting a proper size of iliac bone block. Furthermore, several studies have shown the advantages of using suture button fixation in the revision surgery for failed Bristow-Latarjet procedure. However, the potential inferior biomechanical strength of suture button fixation is still a concern. This Technical Note introduced an arthroscopic "double-inlay" Eden-Hybinette procedure with modified suture button fixation for the revision of failed Bristow-Latarjet. With its "quadruple" reinforcement effect, this procedure can achieve an excellent biomechanical strength of fixation.

Arthroscopic Distal Clavicular Autograft for Congruent Glenoid Reconstruction

Arthroscopic distal clavicular autograft (DCA) is effective in shoulder instability with glenoid bone loss. The original technique uses an osteochondral autograft, fixed with screws or suture anchors. We developed a modified procedure called "congruent arc DCA" characterized by (1) use of drilling guides to optimize graft positioning and make the all-arthroscopic procedure safer and reproducible; (2) rotation of the DCA of 90° to reach a congruent arc with its undersurface; (3) fixation of the graft with cortical buttons to simplify its intra-articular passage, avoid hardware problems, and facilitate possible revision surgery; and (4) intraoperative use of a suture tensioner to achieve satisfactory compression of the graft and increase its consolidation.

No difference in 90-day complication rate following open versus arthroscopic Latarjet procedure

The purpose of this study was to compare the 90-day complication rate between the open and arthroscopic Latarjet procedure. A retrospective review of patients who underwent an open or arthroscopic Latarjet procedure at NYU Langone Health between 2012 and 2019 was performed. The complications, readmissions, and reoperations within 90 days were assessed. Outcomes were compared between the two approaches, and a p value of < 0.05 was considered to be statistically significant. The study included 150 patients (open: 110; arthroscopic: 40), with no patients lost to follow-up within the first 90 days. Both cohorts were similar in terms of patient demographics. No intra-operative complications were observed in either group. Overall, there were 4 post-operative complications with the open approach and 2 with the arthroscopic approach (3.6% and 5.0%, respectively; n.s.) during the study period. Three patients required a readmission within the 90-day period; one patient in both groups required a revision Latarjet for graft fracture, and one patient in the open Latarjet required irrigation and debridement for deep infection (n.s.). With the open approach, there were 2 (2.3%) wound complications, 1 graft complication, and 1 (1.1%) nerve injury. With the arthroscopic approach, there was 1 (2.8%) wound complication and 1 (2.8%) hardware complication. The safety, and 90-day complication and readmission profile of arthroscopic Latarjet is similar to open Latarjet procedure. LEVEL OF EVIDENCE: Level III.

Short-Term Bone Fusion With Arthroscopic Double-Button Latarjet Versus Open-Screw Latarjet

BACKGROUND

Recently, arthroscopic double-button Latarjet (AL) has provided an alternative to conventional open Latarjet (OL) in the treatment of anterior shoulder instability with glenoid bone loss. Therefore, theoretically, the faster fusion is obtained, the sooner return to sports under safe conditions can occur. The emerging flexible fixation of the bone block has clearly offered a new approach to achieve bone fusion. However, the period required to achieve this goal remains controversial.

PURPOSE/HYPOTHESIS

The purpose was to compare computed tomography (CT) scan results of AL and OL in the early postoperative period. It was hypothesized that the bone block fusion with AL would require a longer time than that with OL.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

In a retrospective 1-year study, the authors compared 17 primary double-button AL to 22 primary 2-screw OL procedures indicated for anterior shoulder instability in patients with an Index Severity Instability Score >3 points. These patients were reviewed with a CT scan at 1 day, 3 months, and 6 months postoperatively. The characteristics for the 2 groups were comparable. CT scans aimed to analyze graft position, bone contact area with the scapula, and fusion at 3 and 6 months. Clinical assessment was based on the Walch-Duplay and Rowe scores.

RESULTS

The mean preoperative Index Severity Instability Score was 5.3 ± 1.9 points, with a mean anterior glenoid bone loss of 9.1% ± 4.6%. At 3 months, the rates of fusion were 41% and 100% for the AL and OL groups, respectively (P < .001). This rate increased to 70% in the AL group at 6 months (P = .006). In the axial and sagittal planes, there was no difference in graft position between the AL group and the OL group. The bone block was longer and there was a more extensive bone contact area in the OL group (AL, 131 mm² vs OL, 223 mm²; P < .001). At 6 months of follow-up, no significant difference in clinical scores was noted between the groups: Walch-Duplay score, 93.0 ± 10.9 points versus 91.8 ± 12.5 points (P = .867); and Rowe score, 99.0 ± 2.2 points versus 95.0 ± 8.4 points (P = .307) for the AL and OL groups, respectively.

CONCLUSION

AL required more time to achieve bone block fusion than OL. This finding should be taken into account when considering this procedure for patients in a hurry to return to sports involving the shoulder.

Variation in technique and postoperative management of the Latarjet procedure among orthopedic surgeons

BACKGROUND

The Latarjet procedure has become a treatment of choice for glenohumeral instability in the setting of large glenoid osseous defects (>20%) and for prior failed soft tissue repairs. However, surgical techniques and postoperative rehabilitation protocols vary among expert shoulder surgeons. The purpose of this survey study was to characterize the variation in current practice patterns among fellowship-trained orthopedic shoulder surgeons and identify factors related to variation.

METHODS

A 9-question survey was created (SurveyMonkey, San Mateo, CA, USA) and distributed to orthopedic surgeons who are active members of the American Shoulder and Elbow Surgeons or American Orthopaedic Society for Sports Medicine. The survey asked questions regarding surgeon experience with the Latarjet procedure, fellowship training, open vs. arthroscopic approach, method of coracoid-to-glenoid fixation, period of sling use postoperatively, and time before clearance to return to sport. Subgroup analysis was performed to determine whether further variation was evident between surgeons who completed sports medicine vs. shoulder and elbow fellowship training.

RESULTS

In total, 242 surgeons completed the survey. Of these, 55% indicated performing a sports medicine fellowship and 39% indicated completing a shoulder and elbow fellowship. Among all surgeons, the classic open Latarjet procedure was the strongly preferred technique (79%), followed by the open congruent-arc (17%) and all-arthroscopic (3%) techniques. With respect to fixation, 98% used screw fixation and only 1% indicated cortical button use. With respect to the postoperative course, >85% of surgeons preferred immobilization for 3-6 weeks after the procedure and 42% of respondents stated they waited ≥6 months prior to clearing their patients to return to sport. Subgroup analysis revealed that surgeons who completed a shoulder and elbow fellowship performed the classic open technique 89% of the time compared with 63% of those who completed a sports medicine fellowship (P < .001).

CONCLUSION

The results of our survey study indicate an overall strong preference for the open classic Latarjet technique as well as an overall strong preference for screw fixation of the coracoid graft to the glenoid among all surgeons. Shoulder and elbow fellowship-trained surgeons are significantly more likely to perform open surgery with a classic technique compared with sports medicine fellowship-trained surgeons. Furthermore, the significant variation in postoperative sling use and return to sport suggests that further research is needed to develop an evidence-based postoperative Latarjet rehabilitation protocol.

Non-rigid fixation of the glenoid bone block for patients with recurrent anterior instability and major glenoid bone loss: A systematic review

BACKGROUND

New types of glenoid bone block fixation, involving suture buttons, suture anchors or even implant-free impaction of the graft, have been recently introduced. In contrast to screws which allow for a rigid fixation of the bone block, these alternative procedures provide a non-rigid type of fixation.

METHODS

Two reviewers independently conducted the search in a systematic way (according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) using the MEDLINE/PubMed database and the Cochrane Database of Systematic Reviews. These databases were queried with the terms "Latarjet" OR "Eden-Hybbinette" OR "bone block" AND "anterior" AND "shoulder" AND "instability."

RESULTS

Eight out of the 325 initial studies were finally chosen according to our inclusion-exclusion criteria. In total, 750 patients were included in this review. The overall anterior instability recurrence rate for patients treated with non-rigid fixation was 2.6%, while the overall rate of non-union or graft osteolysis was 5.4%.

CONCLUSIONS

Regardless of the graft type, bone block non-rigid fixation showed satisfactory clinical and functional outcomes for the treatment of anterior shoulder instability with substantial glenoid bone deficiency. Furthermore, non-rigid fixation resulted in adequate bone graft healing and osseous incorporation. Lastly, given the relative lack of data, further prospective controlled studies are required to assess bone block non-rigid fixation procedures in comparison with the traditional rigid (with screws) fixation techniques.

LEVEL

Systematic review, IV.

Clinical and radiographic outcomes after Latarjet using suture-button fixation

Background

Latarjet has become a common treatment option for patients with shoulder instability in the setting of bone loss. The coracoid is commonly secured with screws

Methods

All patients who underwent Latarjet with suture-button fixation with minimum 1-year follow-up were eligible for inclusion. Preoperative demographic and clinical outcome data including American Shoulder and Elbow Surgeons (ASES), Single Assessment Numerical Evaluation (SANE), and Visual Analog Scale (VAS) were recorded and compared with postoperative scores. Radiographs were reviewed for signs of nonunion. Complications were recorded.

Results

Overall 21 patients (76% male, average age: 30.4 ± 11.3 years) underwent Latarjet with suture-button fixation. Significant improvements at 1 year were seen in ASES (P < 0.001), SANE (P < 0.001), and VAS (P = 0.011) scores compared with preoperative scores. Of the 21 patients who had reached 1-year follow-up, 17 (81%) reached 2-year follow-up. For the 17 patients who reached 2-year follow-up, there were significant improvements in ASES (P = 0.001), SANE (P = 0.001), and VAS (P = 0.005) scores from preoperative values. When isolating the 17 patients with 2-year follow-up, there were no significant differences between their 1-year and 2-year ASES (P = 0.73), SANE (P = 0.17), and VAS (P = 0.37) scores. Overall, 3 patients (14%) sustained a complication (one redislocation, one with coracoid migration and a fibrous union, and one superior labral tear requiring biceps tenodesis and superior labral repair).

Conclusion

Suture-button fixation of the coracoid during the Latarjet provides encouraging clinical and radiographic outcomes at 1 and 2 years.

Modification of the Traditional Open Latarjet Technique with the Use of Sutures and Cortical Buttons Instead of Screws

In this article we describe a modification of the open Latarjet technique, using sutures and cortical buttons, for the fixation of the coracoid. The transfer of the coracoid to the anterior glenoid is a popular technique used for complex shoulder instability. The technique is proven to be effective with consistently good results but complications have been reported related to the screws used for the fixation of the coracoid. Recent studies confirm that the suture-button technique for the fixation of the coracoid is biomechanically comparable to the screw fixation. The proposed technique combines the advantages of the open approach and avoids the use of metal screws, potentially minimizing hardware-related complications.

Arthroscopic double-button Latarjet: two-thirds of bone block healed at 90 days

PURPOSE

The aim of this study was to evaluate the union rate and risk factors for delayed union in the early postoperative period after an arthroscopic Latarjet with double-button fixation.

METHOD

In a retrospective study, postoperative CT scans at 3 months were analysed following an arthroscopic Latarjet with double-button fixation used to treat anterior shoulder instability. Healing of the bone block, its position in the sagittal and coronal planes, and the contact area graft/scapula were analysed.

RESULTS

Ninety-eight CT scans (98 patients) were included. The rate of healing at 3 months was 63/98 (64%) and four grafts clearly migrated. The position was perfectly flush to the glenoid rim in 67% and under the equator in 96%. The mean contact graft/scapula area was 135 mm 2 (4-420). In multivariate analysis, the risk of non-union at 3 months was associated with tobacco consumption (p = 0.001, aOR = 12.17 95% CI [2.62-56.49]), absence of preoperative glenoid bone defect (p = 0.003, aOR = 8.06 95% CI [2.06-31.56]), and a contact area graft/scapula less than 120 mm 2 (p = 0.010, aOR = 5.25 95% CI [1.50-18.40]). Among 31 non-united grafts, 93% definitively healed on CT scan at 1 year, leaving an overall rate of 93% of united grafts at last follow-up.

CONCLUSIONS

The rate of union at 3 months after an arthroscopic Latarjet with double-button fixation was 64%, reaching 93% at 1 year. This procedure should be carefully indicated in case of tobacco use or instability without glenoid bone defect, especially when the shoulder is exposed to high-energy trauma in the early phase after surgery.

The novel arthroscopic subscapular quadriceps tendon-bone sling procedure provides increased stability in shoulder cadavers with severe glenoid bone loss

PURPOSE

Treatment of anterior glenoid bone loss in patients with recurrent anterior shoulder instability is a challenge. The subscapular sling method with quadriceps tendon bone (QTB) graft is a modification of the subscapular sling with a semitendinosus (ST) graft. The aim of the study was to test the biomechanical stability of the QTB sling procedure in human shoulder cadavers with severe anterior glenoid bone loss.

METHODS

Fourteen cadaveric shoulders were tested with a force-moment-guided robot in three conditions: physiologically intact, anterior glenoid bone resection, and the subscapular sling procedure with a QTB graft. Joint stability was measured in anterior, anterior inferior and inferior directions in four glenohumeral joint positions: 0° and 60° of glenohumeral abduction, with each at 0° and 60° of external rotation. Maximum external rotation was measured at 0° and 60° glenohumeral abduction. Computer tomography scans were obtained preoperatively to plan the glenoid bone resection, as well as postoperatively to calculate the proportion of the glenoid bone actually resected.

RESULTS

Significantly decreased translations were observed in the shoulders with the QTB sling compared to the intact joint and the glenoid bone loss model. No significant differences in maximum external rotation were observed between the three different conditions.

CONCLUSION

This biomechanical study revealed a significant stabilizing effect of the arthroscopic subscapular QTB graft sling procedure in human shoulder cadavers without compromising external rotation. Clinical trials may reveal the usefulness of this experimental method.

Double-screw and quadruple-button fixation for the glenoid: Latarjet versus bone block applications

Background

The Latarjet and bone block procedures can be secured with screws or cortical buttons. The purpose of this biomechanical study was to compare quadruple buttons vs. double screws for fixation of anterior glenoid bone grafts.

Methods

Twelve cadaveric scapulae (6 pairs) were denuded, resected, and potted. Pairs were randomized to quadruple-button or double-screw fixation after creation of a 15% anterior glenoid defect. The specimens underwent cyclic uniaxial compressive glenoid loading between 50 and 200 N for 1000 cycles at 1 Hz. Testing was repeated for conjoint tendon loads of 0 N (simulating a bone block procedure), 10 N, and 20 N (simulating a Latarjet procedure). Peak resultant relative coracoid graft displacement was optically tracked at 3 points (superior, central, and inferior) on the edge of the coracoid.

Results

No significant differences were found between buttons and screws for bone block applications or with 10 N of conjoint tendon loading (P ≥ .095). At 20 N of conjoint tendon loading, however, the screws were significantly more stable than the buttons (P ≤ .023). During the initial 20-N conjoint load application, all 3 points displaced significantly more with the button reconstruction than with the screws (P ≤ .01). Overall, mean displacements did not exceed 1 mm at any position on the coracoid, regardless of testing condition.

Conclusions

The quadruple-button technique is comparable to screws when the coracoid is used as a bone block or when conjoint tendon loading is minimized. However, at higher conjoint tendon loads, the screws produced a more stable coracoid graft than the buttons.

90-Day Complication Rate After the Latarjet Procedure in a High-Volume Center

BACKGROUND

The Latarjet procedure is indicated for patients with recurrent anterior shoulder instability, previous failed soft tissue stabilization, glenoid bone loss, or high-risk factors for recurrence, although there is still a concern with the surgical complication rates associated with the Latarjet procedure.

PURPOSE

To evaluate the 90-day complication rate after the open Latarjet procedure in a high-volume center.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

A retrospective review was performed of patients who underwent an open Latarjet procedure at our institution over a 5-year period between January 2015 and December 2019. The complications, readmissions, and reoperations within 90 days were evaluated.

RESULTS

A total of 441 patients with a mean age of 23.0 ± 5.7 years was included; 97.5% of the patients were male. There were 2 intraoperative complications (0.5%): 1 coracoid fracture and 1 anaphylactic reaction to vancomycin. Overall, there were 19 postoperative complications (4.3%) in 18 patients, with 4 (0.9%) readmissions for revision surgery. Hematomas were the most common complication, occurring in 12 patients (2.7%), with 9 (2.0%) requiring a return to the operating theater during their stay for an evacuation. In those who required a readmission for a reoperation, 1 was for a hematoma requiring a washout, 2 were for irrigation and debridement of a surgical site infection, and the third was for a biceps tenodesis in a patient with severe bicipital pain. No patients had recurrence or any postoperative graft complications; additionally, there were no neurovascular complications.

CONCLUSION

We found that in a high-volume center, the open Latarjet procedure has a low 90-day complication rate with a low revision rate. Hematomas were the most common complication experienced by patients who underwent the Latarjet procedure, while there was no recurrent instability or neurological or hardware complications reported among the 441 patients included in this study.

Early Follow-Up of Arthroscopic Latarjet Procedure with Screw or Suture-Button Fixation for Recurrent Anterior Shoulder Instability

Objective

To evaluate the early clinical and radiographic results of arthroscopic Latarjet procedure using screw or suture‐button fixation in patients with recurrent anterior shoulder dislocation.

Methods

Twelve patients who underwent arthroscopic Latarjet procedure between January 2015 and December 2018 at our institution were retrospectively studied. Data of the patients' history, including age, gender, side of affected arm, body mass index (BMI), and the number of dislocations since fist dislocation were collected. Preoperative and postoperative clinical follow‐up data were evaluated using Walch–Duplay score, American Shoulder and Elbow Society (ASES) score, and modified Rowe score. Active external rotation and active internal rotation at 90° of abduction as well as active elevation were evaluated preoperatively and postoperatively. The position and healing condition of the transferred coracoid bony graft were also assessed using computed tomography (CT) and Mimics 19.0 software.

Results

Mean follow‐up was 24.9 months (range, 13 to 53 months) of all patients. At final follow‐up, the average ASES score (preoperative vs postoperative values) had improved from 68.9 ± 7.9 to 91.1 ± 6.1 in screw fixation group and 68.9 ± 8.9 to 87.5 ± 6.7 in suture‐button fixation group; the average Rowe score (preoperative vs postoperative values) had improved from 25.0 ± 8.4 to 92.5 ± 4.2 in screw fixation group and 21.7 ± 13.7 to 93.3 ± 4.1 in suture‐button fixation group; the average of Walch–Duplay score (preoperative vs postoperative values) had improved from 12.5 ± 15.1 to 91.7 ± 4.1 in screw fixation group and 18.3 ± 20.7 to 88.3 ± 7.5 in button fixation group. The forward flexion was 175.0° ± 8.4° preoperatively and 178.3° ± 4.1° postoperatively in screw fixation group while 174.8° ± 10.2° preoperatively and 175.0° ± 5.5° postoperatively in suture‐button fixation group. The active external rotation was 77.5° ± 5.2° preoperatively and 71.7° ± 4.1° postoperatively in screw fixation group while 72.5° ± 6.9° preoperatively and 68.3° ± 7.5° postoperatively in suture‐button fixation group. The average of active internal rotation was 66.7° ± 6.1° preoperatively and 67.5° ± 6.1° postoperatively in screw fixation group while 68.3° ± 11.3° preoperatively and 66.7° ± 7.5° postoperatively in suture‐button fixation group. In postoperative CT scan, 91.7% grafts midline center were located at or under the equator in the en face view; 75% of the bone blocks were flush to the glenoid face in the axial view, with only two grafts exhibiting slight medial placement in screw fixation group (33.3%) and one graft exhibiting slight lateral placement in suture‐button fixation group (16.7%). All grafts achieved bone union. Graft absorption mostly occurred outside of the “best‐fit” circle. The average bony absorption rates of the coracoid grafts were 25.2% and 10.18% in screw fixation group and suture‐button fixation group, respectively, at 6 months postoperative follow‐up.

Conclusion

Both suture‐button fixation and screw fixation techniques in arthroscopic Latarjet procedure revealed excellent clinical outcomes with low complication rates in the early follow‐up. The suture‐button fixation exhibited a flexible fixation pattern that allowed for self‐correction to some extent, even slight lateralization could finally remodel over time.

Mechanical behavior of screw versus Endobutton for coracoid bone-block fixation

INTRODUCTION

Arthroscopic coracoid bone-block fixation by Endobutton was developed to avoid the complications associated with screwing. However, few studies have assessed the mechanical characteristics of the two. The aim of the present study was to assess and compare fixation rigidity by screw versus Endobutton. The study hypothesis was that rigidity is lower with Endobutton than with screws.

MATERIAL AND METHOD

3D print-outs of a glenoid and a coracoid process were obtained from CT scans of a patient showing anterior shoulder instability with significant bone defect. Four types of coracoid fixation were implemented: 1 or 2 4.5mm malleolar screws, and 1 or 2 Endobuttons. Three specimens per assembly were placed on a specific test bench. Lateromedial bone-block compression was exerted at 0.1mm/sec at 3 points: superior, central, inferior. The resultant force and bone-block displacement were recorded.

RESULTS

Mean fixation rigidity with 1 screw, 2 screws, 1 Endobutton and 2 Endobuttons was respectively 158N/mm (range, 133-179), 249N/mm (241-259), 10N/mm (5-13) and 14N/mm (13-15), with significant difference between the screw and Endobutton groups (p<0.001). Displacement was greater with 1 than 2 Endobuttons under superior or inferior force, while the difference was non-significant under central force (7.45 vs 6.93mm; p=0.53) CONCLUSIONS: Screw fixation showed greater rigidity, while the Endobutton assembly showed less tension, leading to greater bone-block mobilization. The interest of using two Endobuttons is to reduce displacement under polar pressure. the present biomechanical study confirmed the mechanical vulnerability of bone-blocks fixed by endobutton until consolidation is achieved.

LEVEL OF EVIDENCE

Biomechanical study.

Cortical suture button fixation vs. bicortical screw fixation in the Latarjet procedure: a biomechanical comparison

BACKGROUND

The Latarjet procedure traditionally has been performed with 2 screws in an open manner. Recently, cortical suture button fixation for coracoid transfer has been used in hopes of mitigating complications seen with screw placement. The aim of this study was to evaluate a cortical suture button and technique currently available in the United States compared with screw fixation in the Latarjet procedure in a cadaveric model.

METHODS

We randomly assigned 9 matched pairs of fresh-frozen cadaveric shoulders (N = 18) to undergo the Latarjet procedure with either screw fixation or cortical suture button fixation. After fixation, all shoulders underwent biomechanical testing with direct loading on the graft vas a material testing system. Cyclic testing was performed for 100 cycles to determine axial displacement with time; each graft was then monotonically loaded to failure.

RESULTS

The maximum cycle displacement was significantly less for screw fixation vs. cortical suture button fixation (3.1 ± 1.3 mm vs. 8.9 ± 2.1 mm, P < .0001). The total load at failure was 481.1 ± 88.8 N for screws and 175.5 ± 95.8 N for cortical suture buttons (P < .0001). Bony damage to the surrounding anatomy was more extensive at failure in the screw-fixation group.

CONCLUSION

At time zero, the cortical button fixation and technique did not resist direct loads to the graft as much as traditional screw fixation, although bony damage to the surrounding anatomy was more extensive in screw fixation than button fixation. In the event of unanticipated loading, this could place a patient at higher risk of graft migration, which could lead to unintended early outcomes. These results support the need for implants and techniques specifically tailored to the Latarjet procedure and should bring into question the adoption of a cortical button and technique not specific to the procedure.

A new mini-open technique of arthroscopically assisted Latarjet

BACKGROUND

The aim is to describe a new arthroscopically assisted Latarjet technique.

METHODS

We evaluated the clinical and radiological findings of 60 patients with chronic recurrent anterior gleno-humeral instability who underwent, between September 2013 and November 2014, an arthroscopically-assisted Latarjet procedure with double round endobutton fixation. Inclusion criteria were: chronic anterior recurrent instability, Instability Severity Index Score (ISIS) greater than three points, a glenoid bone defect > 15% or a Hill Sachs lesion with concomitant glenoid bone defect > 10%. During surgery the joint capsule and the anterior glenoid labrum were detached. Two drill tunnels perpendicular to the neck of the glenoid were made through a guide. An accessible pilot hole through the glenoid was created to allows the passage of guidewires for coracoid guidance and final fixation onto the anterior glenoid. Through a restricted deltopectoral access a coracoid osteotomy was made. Finally, the graft was prepared, inserted and secured using half-stitches.

RESULTS

The mean follow-up was 32.5 months (range 24-32 months). At a mean follow-up, 56 of the 60 subjects claimed a stable shoulder without postoperative complaints, two (3.3%) had an anterior dislocation after new traumatic injury, and two (3.3%) complained of subjective instability. At the latest follow-up, four subjects complained of painful recurrent anterior instability during abduction-external rotation with apprehension. At 1 year, the graft had migrated in one patient (1.7%) and judged not healed and high positioned in another patient (1.7%). Moreover, a glenoid bony gain of 26.3% was recorded. At the latest follow-up, three patients had grade 1 according to Samilson and Prieto classification asymptomatic degenerative changes. Nerve injuries and infections were not detected. None of the 60 patients underwent revision surgery. Healing rate of the graft was 96.7%.

CONCLUSIONS

This technique of arthroscopically assisted Latarjet combines mini-open and arthroscopic approach for improving the precision of the bony tunnels in the glenoid and coracoid placement, minimizing any potential risk of neurologic complications. It can be an option in subjects with anterior gleno-humeral instability and glenoid bone defect. Further studies should be performed to confirm our preliminary results.

TRIAL REGISTRATION

Trial registration number 61/int/2017 Name of registry: ORS Date of registration 11.5.2017 Date of enrolment of the first participant to the trial: September 2013 'retrospectively registered' LEVEL OF EVIDENCE: IV.

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.

The Effect of Screw Design and Cortical Augmentation on Insertional Torque and Compression in Coracoid-Glenoid Fixation in a Sawbones Model

PURPOSE

To compare screw insertional torque and coracoid-glenoid compression from 4 fixation techniques with different screw design parameters and cortical augmentation for the Latarjet procedure.

METHODS

Simulated Latarjet procedures were performed with 4 fixation techniques using laminated polyurethane blocks with dimensions similar to the coracoid-glenoid construct. The groups included DePuy Synthes Mitek 3.5-mm partially threaded screws with top hats, Arthrex 3.75-mm fully threaded screws with a 2-hole plate, Arthrex 3.75-mm fully threaded screws, and Smith & Nephew 4.0-mm partially threaded screws. Screws were inserted using a digital torque-measuring screwdriver to determine maximum insertional torque. Pressure-sensitive film was used to measure the maximum contact pressure and the effective pressure distribution (EPD) between the coracoid and glenoid; the EPD represents the percentage of the film's surface area that experienced pressure greater than 10 MPa. One-way analysis of variance and post hoc tests were used for statistical analysis.

RESULTS

Significant differences were found between the 4 fixation groups for each variable measured. The 2 cortically augmented systems produced significantly higher maximum insertional torque than the non-cortically augmented systems (P < .001 for both). The 3.75-mm screws with a 2-hole plate yielded significantly higher contact pressures than the 4.0-mm screws (P = .028). This group also had a high EPD, with a mean value more than double the values of the non-cortically augmented systems (P = .037 and P < .001).

CONCLUSIONS

Cortically augmented fixation methods showed higher maximum insertional torque, maximum contact pressure, and EPD between the surfaces of the coracoid and glenoid in this Sawbones model.

CLINICAL RELEVANCE

Various implants are available for the Latarjet procedure, but their biomechanical characteristics have not yet been fully elucidated. Graft fracture and nonunion represent 2 modes of failure that may be related to insertional torque and coracoid-glenoid compression. This study compared screw insertional torque and compression achieved using 4 fixation techniques with different screw design parameters and cortical augmentation in a Sawbones model.