Arthroscopic Bone Block Cerclage: A Fixation Method for Glenoid Bone Loss Reconstruction Without Metal Implants

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.

Clinical Outcomes and Graft Resorption After Metal-Free Bone Block Suture Tape Cerclage Fixation for Recurrent Anterior Shoulder Instability: A Computed Tomography Analysis

BACKGROUND

Glenoid reconstruction with a bone block for anterior glenoid bone loss (GBL) has shown excellent outcomes. However, fixation techniques that require metal implants are associated with metal-related complications and bone graft resorption.

HYPOTHESIS

Arthroscopic glenoid reconstruction using a tricortical iliac crest bone graft (ICBG) and metal-free suture tape cerclage fixation can safely and effectively restore the glenoid surface area in patients with recurrent anterior shoulder instability and anterior GBL.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

Adult patients (≥18 years) of both sexes with recurrent anterior shoulder instability and anterior GBL ≥15% were enrolled. These patients underwent arthroscopic glenoid reconstruction with ICBGs and metal-free suture tape cerclage fixation. The effectiveness and clinical outcomes with this technique were evaluated at 24 months using functional scores. Resorption of the graft articular surface was assessed by computed tomography, with the graft surface divided into 6 square areas aligned in 2 columns. Descriptive analysis was conducted.

RESULTS

A total of 23 consecutive patients met inclusion criteria (22 male, 1 female; mean age, 30.5 ± 7.9 years). The mean preoperative GBL was 19.7% ± 3.4%, and there were 15 allograft and 8 autograft ICBGs. All patients exhibited graft union at 3 months. The median follow-up was 38.5 months (interquartile range, 24-45 months). The Western Ontario Shoulder Instability Index, Rowe, Constant-Murley, and Subjective Shoulder Value scores improved from preoperatively (35.1%, 24.8, 83.1, and 30.9, respectively) to postoperatively (84.7%, 91.1, 96.0, and 90.9, respectively) (P < .001). No differences in clinical scores were observed between the graft types. One surgical wound infection was reported, and 2 patients (8.7% [95% CI, 2.4%-26.8%]) required a reoperation. The mean overall glenoid surface area increased from 80.3% ± 3.5% to 117.0% ± 8.3% immediately after surgery before subsequently reducing to 98.7% ± 6.2% and 95.0% ± 5.7% at 12 and 24 months, respectively (P < .001). The mean graft resorption rate was 18.1% ± 7.9% in the inner column and 80.3% ± 22.4% in the outer column. Additionally, 3 patients treated with an allograft (20.0% [95% CI, 7.1%-45.2%]), including the 2 with clinical failures, exhibited complete graft resorption at the last follow-up.

CONCLUSION

Arthroscopic glenoid reconstruction using an ICBG and metal-free suture tape cerclage fixation was safe and effective, yielding excellent clinical outcomes. Resorption of the graft articular surface predominantly affected the nonloaded areas beyond the best-fit circle perimeter.

The Subscapularis-Sparing "Flipped Latarjet" Procedure

The Latarjet procedure is a proven and effective operation to treat anterior shoulder instability. Especially in cases with anterior glenoid bone loss, the Latarjet operation is the most popular procedure to restore glenoid anatomy and avoid further dislocations. Next to the re-creation of the missing glenoid bone, the sling effect of the conjoint tendon transferred between a split in the subscapularis muscle is an important "soft tissue stabilizer" of the humeral head. However, it has been shown that the inferior part of the subscapularis muscle tends to degenerate, leading to fatty infiltration of the muscle itself. Also, exposure through the subscapularis split is technically demanding, and there is a risk of nerve damage due to the pulling forces of the retractors during open surgery. When performing the procedure arthroscopically, extremely low and medial portals are necessary to find a correct angle for the glenoid drilling when approaching from anterior. Neurovascular structures may be at risk during these surgical steps. The aim of the flipped Latarjet procedure is to facilitate a safe and reliable arthroscopic operation to anteriorly stabilize the shoulder by transferring the coracoid to the deficient glenoid without splitting the subscapularis muscle while keeping the benefits of a sling effect of the conjoined tendon.

Editorial Commentary: Button Fixation for Glenoid Bone Grafting Results in Less Graft Resorption Compared to Screws

Iliac crest bone grafting is conducted in cases of anteroinferior shoulder instability with substantial bone loss of the glenoid rim to reconstruct the glenoid concavity and its stabilizing function. The technique is more than 100 years old, and it evolved to include graft fixation with metal screws. The disadvantages of metal screw fixation include risk of screw migration, loosening, and breakage, as well as irritation and injury to the surrounding osseous and soft tissue structures (e.g., humeral cartilage and subscapularis muscle). With the implementation of arthroscopic techniques, new graft fixation techniques were introduced, including absorbable or biologic screws, buttons, interconnected suture anchors, and bone cerclage techniques. Recent research shows button fixation is a successful alternative to screw fixation. In addition, buttons show less graft resorption and related pain.

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.

Assessment of micromotion at the bone-bone interface after coracoid and scapular-spine bone-block augmentation for the reconstruction of critical anterior glenoid bone loss-a biomechanical cadaver study

BACKGROUND

Glenoid bone loss is among the most important risk factors for recurrent anterior shoulder instability, and a bony reconstruction is recommended in cases of critical bone loss (> 15%). The commonly used surgical techniques, including coracoid transfer, are associated with considerable complications. The aim of this study was to assess the motion at the glenoid-bone-block interface after coracoid and spina-scapula bone-block reconstruction of the anterior glenoid.

METHODS

Twelve cadaveric shoulders were tested. A 20% bone defect of the anterior glenoid was created, and the specimens were randomly assigned for glenoid augmentation using a coracoid bone block (n = 6) or a scapular spine bone block (n = 6). The glenoid-bone interface was cyclically loaded for 5000 cycles with a force of 170 N. The micromotion was tracked using an optical measurement system (GOM ARMIS) and was evaluated with the GOM Correlate Pro software.

RESULTS

The most dominant motion component was medial irreversible displacement for the spina-scapula (1.87 mm; SD: 1.11 mm) and coracoid bone blocks (0.91 mm; SD: 0.29 mm) (n.s.). The most medial irreversible displacement took place during the first nine cycles. The inferior reversible displacement was significantly greater for spina-scapula bone blocks (0.28 mm, SD: 0.16 mm) compared to coracoid bone blocks (0.06 mm, SD: 0.10 mm) (p = 0.02).

CONCLUSIONS

The medial irreversible displacement is the dominant motion component in a bone-block reconstruction after a critical bone loss of the anterior glenoid. The spina-scapula and coracoid bone blocks are comparable in terms of primary stability and extent of motion. Thus, spina-scapula bone blocks may serve as alternatives in bony glenoid reconstruction from a biomechanical point of view.

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.

Management of off-track Hill-Sachs lesions in anterior glenohumeral instability

Bone loss has been identified as a risk factor for recurrent shoulder dislocations or failure after soft tissue repair. Although the range for "critical" bone loss is yet to be determined, glenoid and humeral bone defects should not be regarded as independent problems, but the interaction between them during shoulder motion should be evaluated as suggested by the glenoid track concept. The glenoid track concept is now widely accepted and considered essential for making decisions about surgery. Soft-tissue procedures usually work well in patients with on-track Hill-Sachs lesions but in off-track lesions do not. In this situation additional procedures should be performed.Different surgical options have been described to address off-track Hill-Sachs lesions, most commonly remplissage, Latarjet or free bone block procedures. Coracoid graft and free bone grafts convert the off-track Hill-Sachs lesion into on-track by lengthening the glenoid-track, whereas remplissage fill-in the humeral lesion so that it does not engage. In the setting of a Hill-Sachs lesion with little or no glenoid bone loss, remplissage has demonstrated satisfactory outcomes with a low complications and recurrence rate. Favorable results have been reported with glenoid bone grafting when managing isolated Hill-Sachs or bipolar lesions. Studies analyzing Latarjet and Eden-Hybinette procedures show that both procedures are safe and effective in the management of anterior glenohumeral instability. Attention should be paid to those patients with large bone defects not amenable to be restored with an isolated Latarjet that may be better addressed with an Eden-Hybinnete or adding a remplissage to the Latarjet procedure.

Arthroscopic Anterior Glenoid Bone Grafting for Shoulder Instability Using an Interconnected Suture Anchor Technique

Anterior bone grafting is an established and frequently used treatment option for recurrent anterior shoulder instability in combination with significant glenoid bone loss. Several open and arthroscopic fixation techniques have been presented to this field in recent years. Some of these techniques are associated with different peri- and postoperative problems or complications. Therefore, the technical gold standard for anterior bone grafting has not been determined, resulting in an ongoing evolvement of bone-grafting techniques. Arthroscopic, metal-free fixation procedures were introduced to the field bone grafting to overcome previous problems of screw fixation. These metal-free techniques frequently include surgically challenging transglenoidal drilling and are placing anterior soft tissues and neurovascular structures at risk. We therefore present an arthroscopic anterior, PEEK (polyether ether ketone)-anchor based, interconnecting bone-grafting technique bypassing previous challenges to restore the anterior glenoid bone stock with adequate positioning and fixation of the bone graft.

Metal-Free Fixation for Free Bone-Block Reconstruction of Chronic Anteroinferior Shoulder Instability

Background:

Anterior shoulder instability is common and may cause a considerable effect on quality of life. For cases with glenoid bone loss, there is still a controversial discussion regarding the optimal treatment. Most of the recent methods are using metal implants to attach the needed graft to the glenoid with reported disadvantages such as metal impingement, damage to the humeral head, cartilage destruction, and premature arthritis.

Indications:

(1) Erosion-type defects with significant bone loss (>15%-20%); (2) chronic fragment-type defects if the size of the fragment is not large enough for an anatomical reconstruction; and (3) non-reconstructible, multifragmented acute fragment type of lesions.

Technique Description:

After placing the patient in a lateral decubitus position and fixing the arm in a traction devise, 3 arthroscopic entries are established: a posterior portal, an anterosuperior portal, and an anteroinferior portal. A harvested tricortical iliac crest bone graft is provided with 2 drilling holes which match the drilling holes through the glenoid. The tapes are then placed from the posterior to the anterior side of the glenoid, and then the graft is passed from the anterior to the posterior side, thus compressing the cancellous side of the bone block onto the glenoid defect. A following interconnection of the sutures creates a continuous loop. The end of the tapes was loaded into a pretied racking hitch knot system, which creates sliding knots between the 2 pair of tapes, whereon the knots can be reduced to the glenoid in a symmetrical fashion. Finally, the reconstruction of the anterosuperior labrum can be done, to cover the bone block with enough soft tissue.

Results:

First short-term results show radiographic consolidation after 3 months and an increased median glenoid estimated surface area at 12 months. The functional scores showed good outcomes, and there were no serious complications reported.

Discussion/Conclusion:

The presented arthroscopic reconstruction of the glenoid using a tricortical bone graft and high-strength fiber tapes provides a metal-free technique which results in a high primary stability of the construct and should therefore be considered when treating anterior shoulder instability with significant bone loss.

Arthroscopic Bone Block Cerclage Technique Using a Tricortical Scapular Spine Autograft for Glenoid Reconstruction in Patients With Anterior Shoulder Instability

In the treatment of anterior shoulder instability with glenoid bone loss, free bone graft transfers have proven to be a viable anatomic alternative to the commonly performed, nonanatomic Latarjet procedure. Implant-free fixation of the free bone grafts, in particular, has rendered excellent short- and long-term results. However, a drawback remains the source of the graft. We describe an arthroscopic bone block cerclage technique using a tricortical scapular spine autograft, which provides an anatomic arthroscopic glenoid reconstruction with the combined benefit of sparing the subscapularis, metal-free fixation, and intraregional donor site for autograft harvesting.

Arthroscopic Iliac Crest Bone Graft Augmentation Using All-Suture Anchors for Shoulder Instability Caused by Glenoid Bone Loss

Augmentation of the anterior glenoid with bone graft is an established treatment for recurrent anterior instability due to critical glenoid bone loss. Both open and arthroscopic techniques have been described. Fixation with metal screws through an open approach is the most common technique, but the risk of metal screw-related complications remains a concern. A variety of arthroscopic techniques using suspensory fixation or suture anchors have been described in the literature. However, they all require a posterior incision to insert a targeting device or to manage sutures. We describe a technique for arthroscopic bone grafting of the anterior glenoid via a purely anterior approach with 2 linked knotless suture anchors, thereby avoiding posterior suture management and glenoid metalwork complications.

Current concepts in anterior glenohumeral instability: diagnosis and treatment

The glenohumeral joint is the most dislocated articulation, accounting for more than 50% of all joint dislocations. The reason behind shoulder instability should be investigated in detail for successful management, and the treatment plan should be individualized for all patients. Several classification systems have been proposed for glenohumeral instability. A physical exam is mandatory no matter what classification system is used. When treating patients with anterior shoulder instability, surgeons need to be aware of the critical size of the bone loss, which is commonly seen. The glenoid track concept was clinically adopted, and the measurement of the glenoid track for surgical decision-making is recommended. Detailed assessment of existing soft tissue injury to the labrum, capsule, glenohumeral ligaments, and rotator cuff is also mandatory as their presence influences the surgical outcome. Rehabilitation, arthroscopic repair techniques, open Bankart procedure, capsular plication, remplissage, Latarjet technique, iliac crest, and other bone grafts offer the surgeon different treatment options according to the type of patient and the lesions to be treated. Three-dimensional (3D) technologies can help to evaluate glenoid and humeral defects. Patient-specific guides are low-cost surgical instruments and can be used in shoulder instability surgery. 3D printing will undoubtedly become an essential tool to achieve the best results in glenohumeral instability surgery.

Arthroscopic bone block metal-free fixation for anterior shoulder instability. Short-term functional and radiological outcomes

INTRODUCTION

Anterior glenohumeral bone loss reconstruction reduces failure rates after soft tissue surgery in patients with large glenoid bone defects. Multiple bone block techniques have been described, most with metal hardware fixation. The objective of this study is to evaluate the safety, as well as the short-term functional and radiological results of an arthroscopic bone block metal-free fixation or bone block cerclage.

MATERIAL AND METHODS

Retrospective study of patients with glenohumeral instability and>15% glenoid bone loss operated during 2019 with follow-up of at least 12 months. Radiography and computerized tomography studies were performed. Functional outcomes were evaluated before and after surgery with the Western Ontario Shoulder Instability Index and Rowe score.

RESULTS

A total of 21 patients with a median age of 30.6 (SD 7.1) were included. All showed radiographic consolidation at 3 months follow-up. A percentage of 90.4 of bone grafts presented osteolysis at peripherical areas and 95.2% revealed consolidation in the areas with contact to the glenoid. The median glenoid estimated surface went from 79.3% before surgery to 98.4% at 12 months. Functional scores were statically significant (P<.001) for Western Ontario Shoulder Instability Index (35.6-86.9) and Rowe score (25.2 to 96.4). No serious complications were reported.

CONCLUSION

The bone block cerclage is a safe, metal-free technique that achieves total consolidation of the bone graft and favorable functional and radiological outcomes at 12 months follow-up.

Investigation of Mg-xLi-Zn alloys for potential application of biodegradable bone implant materials

Implant therapy after osteosarcoma surgery is a major clinical challenge currently, especially the requirements for mechanical properties, degradability of the implants, and their inhibition of residual tumor cells. Biodegradable magnesium (Mg) alloy as medical bone implant material has full advantages and huge potential development space. Wherein, Mg-lithium (Li) based alloy, as an ultra-light alloy, has good properties for implants under certain conditions, and both Mg and Li have inhibitory effects on tumor cells. Therefore, Mg-Li alloy is expected to be applied in bone implant materials for mechanical supporting and inhibiting tumor cells simultaneously. In this contribution, the Mg-xLi-Zinc (Zn) series alloys (x = 3 wt%, 6 wt%, 9 wt%) were prepared to study the influence of different elements and contents on the structure and properties of the alloy, and the biosafety of the alloy was also evaluated. Our data showed that the yield strength, tensile strength, and elongation of as-cast Mg-xLi-Zn alloy were higher than those of as-cast Mg-Zn alloy; Mg-xLi-Zn alloy can kill osteosarcoma cells (MG-63) in a concentration-dependent manner, wherein Mg-3Li-Zn alloy (x = 3 wt%) and Mg-6Li-Zn alloy (x = 6 wt%) promoted the proliferation of osteoblasts (MC3T3) at a certain concentration of Li. In summary, our study demonstrated that the Mg-6Li-Zn alloy could be potentially applied as a material of orthopedic implant for its excellent multi-functions.

The glenoid and humeral head in shoulder osteoarthritis: A comprehensive review

The key management of glenohumeral osteoarthritis is shoulder arthroplasty which aims to reduce pain and restore full shoulder function: it has increased in recent years. A detailed understanding of the anatomy of the glenoid and humeral head, as well as morphological changes of the glenoid in osteoarthritis, are important factors to consider when deciding on replacement components. This review begins with a brief introduction of the glenohumeral joint itself, and then considers the detailed anatomy of the glenoid fossa and humeral head, both of which are reported to have variable morphology. Several studies have been undertaken to assess various parameters, especially of the glenoid fossa including its shape, height, width, and articular surface area, version and inclination, in an attempt to define a standard classification that can be applied to surgical intervention. Nevertheless, no definitive consensus concerning the classification of these morphologies has been forthcoming, hence the need for this review. Following a consideration of these morphologies, the current state of knowledge regarding glenoid deformity in osteoarthritis, as well as its surgical management, is considered.

Arthroscopic "Bone Block Cerclage" Technique for Posterior Shoulder Instability

Many open and arthroscopic techniques have been described to treat posterior glenohumeral instability. Multifactorial features of posterior shoulder instability pathoanatomy and varied patient characteristics have challenged the understanding of this condition and have led to dissimilar results, without a strong consensus for the most adequate technique to treat it. We describe an arthroscopic anatomical metal-free posterior glenoid reconstruction technique, using a tricortical iliac crest allograft with 2 ultra-high strength sutures (FiberTape Cerclage System; Arthrex, Naples, FL) with concomitant posterior capsulolabral complex reconstruction procedure.