Scapula plating system for fixation of acromion fractures

Abstract

A scapula plating system for fixing an acromion fracture in a scapula is described. The system comprises an elongate acromion plate with a medial end having bone screw holes and a lateral end having suture holes. The medial end is configured for attachment to the spine of the scapula with bone screws, while the lateral end is configured for attachment to the acromion with sutures through the suture holes, securing at least one of the deltoid muscle or its tendon. This arrangement reduces the risk of bone screw pull-out due to forces exerted by the deltoid muscle, particularly in cases where the acromion is relatively thin or compromised by conditions such as osteoporosis.

Description

Scapula Plating System for Fixation of Acromion FracturesField of the Invention

[0001] The present invention relates to orthopaedic devices and, more particularly, to a scapula plating system designed for the fixation of acromion fractures. The invention specifically addresses issues related to secure fixation of the acromion, particularly in cases where the acromion is compromised by conditions such as osteoporosis, by utilising a combination of bone screws and sutures to provide improved stability and resistance to muscular forces exerted by the deltoid muscle.Background of the Invention

[0002] The scapula, commonly referred to as the shoulder blade, plays a vital role in upper limb mobility and stability. It forms part of the shoulder girdle and provides attachment points for muscles responsible for arm movement, including the deltoid, trapezius, and rotator cuff groups. The scapula includes several anatomically distinct regions such as the spine, glenoid, and acromion. The acromion, projecting from the superior aspect of the scapula, forms part of the acromioclavicular joint and provides the insertion for the deltoid muscle. Because of its exposed position and the forces exerted by the surrounding musculature, the acromion is vulnerable to fracture, which can compromise shoulder movement and function.

[0003] Acromion fractures are observed in both traumatic and degenerative contexts. They may occur following direct impact to the shoulder or through indirect stress transmitted by muscular forces. These injuries are often encountered in active individuals involved in high-impact activities and in elderly patients affected by osteoporosis, in whom diminished bone density further weakens the acromial structure. Fixation of such fractures presents a challenge, as the acromion is relatively thin and subject to continuous tension generated by the deltoid muscle during arm elevation.

[0004] Various fixation techniques and plating systems have been proposed to address this problem. For example, a scapula plating system described in WO 2023 / 203042 A1 (UNIV GENT) 26 October 2023 discloses a plate for fixation ofacromial or scapular fractures using a combination of bone screws and suture passages that may be employed for attachment to the acromion and surrounding soft tissue.

[0005] Although such approaches seek to enhance fixation stability and distribute forces acting on the acromion, they remain representative of general developments in scapular fixation technology. These arrangements typically rely on combinations of bone screws and auxiliary suture passages to secure the plate and adjacent tissues, yet challenges continue to arise in achieving consistent fixation in anatomically thin or osteoporotic bone regions and in managing the complex load conditions generated by shoulder movement.

[0006] It is to be understood that, if any prior art information is referred to herein, such reference does not constitute an admission that the information forms part of the common general knowledge in the art, in Australia or any other country.Summary of the Disclosure

[0007] The present scapula plating system is premised on the discovery that the effectiveness of conventional acromion fixation arrangements is dependent on the structural integrity of the acromial bone, which is often thin and subjected to substantial forces generated by the deltoid muscle during arm movement. In cases where the acromion is weakened, such as in osteoporotic bone, these tensile forces can cause loosening or failure of fixation between the plate and the bone, whether the fixation is achieved by bone screws or sutures, particularly in the lateral portion of the acromion where bone stock is limited. Such failures compromise fixation stability, impede healing, and may require further surgical intervention, demonstrating the limitations of relying solely on bone-anchored fixation under dynamic muscular loading.

[0008] A scapula plating system for fixation of acromion fractures comprises an elongate acromion plate having a medial end secured to the scapular spine by bone screws and a lateral end attached to the acromion by sutures that engage directly with the deltoid muscle or its tendon. The sutures transmit tensile forces generated by deltoid contraction through the sutures into the plate, reducing load transfer to theacromion and lessening reliance on bone fixation in regions of limited cortical strength. This direct deltoid-to-plate coupling establishes a controlled load-sharing construct that redistributes muscular forces through the plate to the scapular spine, maintaining fixation stability even in osteoporotic bone and mitigating the risk of loosening or failure under physiological shoulder movement.

[0009] In some embodiments, the lateral end of the acromion plate may be free of bone screws, relying entirely on suture-based fixation to reduce the risk of hardware loosening or pull-out in the relatively thin or osteoporotic acromial bone. This configuration enables fixation through soft-tissue engagement rather than direct cortical anchorage, maintaining secure attachment under cyclic deltoid loading.

[0010] The lateral end may be formed wider than the medial end, providing an increased contact area for suture placement and promoting more uniform distribution of tensile forces transferred from the deltoid. This widened geometry also accommodates a greater number of suture holes or button interfaces without increasing local stress concentration.

[0011] In preferred arrangements, the acromion plate may incorporate anatomical curvature along its transverse plane, shaped to conform closely to the superior contour of the scapula. This conformation assists in achieving intimate contact between the plate and bone, minimising soft-tissue irritation and ensuring accurate load transfer through the fixation construct.

[0012] The medial end can include five or more bone screw holes to facilitate multipoint anchorage to the scapular spine, allowing the use of both locking and nonlocking bone screws for combined angular stability and compressive fixation. Such screw placement along the medial end enhances overall rigidity while maintaining controlled flexibility at the lateral fixation interface.

[0013] In various examples, the lateral end may include seven or more suture holes, distributed along its periphery to allow versatile routing and tensioning of sutures according to individual patient anatomy. Locating the suture holes along both posterior and lateral edges of the plate enables secure engagement of the posteriorand lateral deltoid fibres, which are responsible for the majority of the tensile loading during abduction.

[0014] Certain embodiments intentionally omit suture holes along the anterior edge of the plate to prevent interference with the anterior deltoid and adjacent soft tissues, reducing postoperative irritation and facilitating a natural range of motion.

[0015] The lateral end may further define a series of insert apertures configured to receive superior suture buttons that can be used to anchor sutures or to form a clamping assembly with corresponding inferior buttons. The superior buttons may each include paired apertures for suture passage, providing stable knot seating and improved load transfer between the superior and inferior button components.

[0016] In some examples, the insert apertures are aligned along a longitudinal axis of the acromion plate to maintain a consistent tension path across the acromion. This arrangement promotes predictable suture orientation and facilitates reproducible surgical technique.

[0017] In yet further configurations, an inferior suture button or series of buttons may be positioned beneath the acromion, aligned with the superior buttons, and coupled via the sutures to generate a compressive clamping force across the acromion. The inferior buttons may include multiple suture holes to allow differential load distribution and to limit focal bone pressure.

[0018] When used in combination, the superior and inferior suture buttons form a dualbutton construct that effectively converts tensile forces generated by deltoid contraction into stabilising compression across the fracture site, thereby enhancing construct stability and maintaining alignment throughout the postoperative healing phase.

[0019] Other aspects of the invention are also disclosed.Brief Description of the Drawings

[0020] Notwithstanding any other forms which may fall within the scope of the present invention, preferred embodiments of the disclosure will now be described, by way of example only, with reference to the accompanying drawings in which:

[0021] Figure 1 shows a scapula plating system in accordance with an embodiment;

[0022] Figure 2 shows a posterior view of a scapula with the system installed thereon;

[0023] Figure 3 shows a disassembled view of a lateral end of an acromion plate and associated componentry in accordance with an embodiment;

[0024] Figure 4 shows a top perspective view showing an inferior suture button in accordance with an embodiment; and

[0025] Figure 5 illustrates an additional embodiment of the scapula plating system as applied to an anatomical model of the scapulaDescription of Embodiments

[0026] Figures 1 and 2 illustrate a scapula plating system 100 designed for the fixation of an acromion fracture in a scapula 101. The system 100 includes an elongate acromion plate 102, typically manufactured from a rigid biocompatible metal such as titanium, stainless steel, or cobalt-chromium alloy. The acromion plate 102 comprises a medial end 103 with bone screw holes 104 and a lateral end 105 with suture holes 106. As shown in Figure 2, the medial end 103 is configured for attachment to the spine 107 of the scapula 101 using bone screws 109 inserted through the bone screw holes 104. The lateral end 105 is configured for attachment to the acromion 108 of the scapula 101 by sutures extending through the suture holes 106 and also engaging directly with at least one of a deltoid muscle or a tendon of the deltoid muscle.

[0027] In use, the sutures are secured so as to establish a direct mechanical connection between the deltoid muscle or its tendon and the acromion plate 102. Each suture may be passed through one of the suture holes 106 in the lateral end 105 of the plate and directed distally toward the deltoid insertion, where it is passed transversely through the deltoid tendon or looped through the adjacent muscle fibres in a locking or figure-of-eight configuration. The suture is then drawn taut and anchored to the plate surface by knotting, clamping, or engaging a suture button, thereby creating a continuous load path from the deltoid to the plate. Under physiological motion, contraction of the deltoid muscle applies tensile force to the sutures, which transmit the load into the plate rather than into the weakened acromial bone. The force is then distributed along the plate and dissipated into the scapular spine through the medial fixation screws. By redirecting deltoid-generated tensileloading through the suture-plate construct, the arrangement reduces dependence on bone screw fixation at the acromion, enhances resistance to cyclic muscular stress, and maintains stable anatomical alignment even in osteoporotic or thin bone. The resulting construct provides a compliant yet robust fixation that remains secure under dynamic shoulder movement while preserving anatomical conformity and soft-tissue integrity.

[0028] It should be noted that the placement of the acromion plate 102 may vary according to the location and nature of the fracture. The lateral end 105 is generally positioned lateral to the acromion fracture, while the medial end 103 is positioned medial to the fracture to engage the stronger scapular spine 107. This configuration allows forces generated by the deltoid to be channelled through the plate across the fracture line, facilitating stabilisation and healing.

[0029] Preferably, the sutures are also passed through the acromion 108 itself to achieve additional purchase through the bone, thereby securing the acromion to the lateral end 105. In the illustrated embodiments, the lateral end 105 may be attached exclusively by sutures without any bone screws 109, eliminating the risk of screw pullout or stress concentration in thin or osteoporotic bone. The lateral end 105 may be wider than the medial end 103 to increase surface area for suture engagement and to promote even force distribution. The acromion plate 102 may further incorporate anatomical curvature along the transverse plane to conform closely to the scapular surface, enhancing fit and reducing local irritation to surrounding soft tissue. This contoured geometry ensures intimate contact between the plate and bone, while still allowing compliant motion of the soft-tissue interface provided by the deltoidengaging sutures.

[0030] The medial end 103 is preferably configured with more than three bone screw holes 104, and in the embodiment shown, it contains at least five bone screw holes 104. Various types of bone screws 109 may be used, including locking cortical bone screws to maintain angular stability and non-locking compression bone screws to allow controlled compression across the fracture. These screw configurations providerigid fixation along the scapular spine while allowing the lateral fixation to rely on the flexible, muscle-coupled suture architecture.

[0031] The lateral end 105 preferably includes more than five suture holes 106, and in the embodiment shown, it includes at least seven suture holes 106. In certain variations, the lateral end 105 may feature at least ten suture holes 106 for securing the deltoid muscle or its tendon with corresponding sutures. These suture holes 106 are predominantly located along the periphery of the lateral end 105, allowing the surgeon to access the deltoid tendon from multiple angles and to tie or weave sutures directly through the tendon or muscle fibres. The increased number of suture holes provides flexibility in surgical technique and allows tailored tensioning to optimise the distribution of deltoid loads.

[0032] As depicted in Figure 1 , the suture holes 106 may be arranged along the posterior edge 110 and lateral edge 111 of the lateral end 105. This configuration ensures that the sutures are positioned to engage the posterior and lateral deltoid muscle fibres, which exert the most significant tensile forces on the acromion, while avoiding the anterior deltoid, which primarily attaches along the clavicle. In the illustrated embodiment, the acromion plate 102 intentionally omits suture holes along its anterior edge to prevent interference with the anterior deltoid and surrounding soft tissues. The combination of posterior and lateral placement of the suture holes allows multidirectional distribution of tensile loads, contributing to the plate’s overall stability and load-sharing performance.

[0033] With reference to Figure 3, the lateral end 105 of the acromion plate 102 may also define insert apertures 112 for engaging superior suture buttons 113. These insert apertures 112 are distinct from the suture holes 106 and are designed for mechanical engagement with suture-button assemblies that enhance the stability and strength of the suture fixation. The superior suture buttons 113 are configured to wedge into the insert apertures 112 to provide additional fixation through the acromion 108. The insert apertures 112 are typically aligned in a row along the longitudinal axis of the acromion plate 102, allowing the surgeon to position the suture buttons in a manner that follows the natural contour and loading path of the acromion.

[0034] Holes may be drilled through the acromion 108 in alignment with the insert apertures 112 to permit passage of sutures and insertion of corresponding inferior suture toggle buttons 114, as illustrated in Figure 4. The inferior suture buttons 114 are inserted lengthwise through these drilled apertures and subsequently rotated or “flipped” beneath the acromion to assume a transverse orientation that anchors them against the bone’s undersurface. In some embodiments, a unitary elongate inferior suture button 114 is employed to distribute tensile loads over a wide area beneath the acromion, while in other variations, multiple shorter inferior suture buttons 114 are used for modular fixation.

[0035] Once the inferior buttons 114 are in place, sutures are passed through the inferior suture buttons and tied off using the superior suture buttons 113, which are retained within the insert apertures 112 of the plate. Each superior suture button 113 may feature a pair of apertures 115 through which the suture limbs are passed and tied securely. The cooperation between the superior and inferior buttons creates a dual-button construct that transfers tensile loads from the deltoid into compressive retention across the acromion. This biomechanical arrangement converts muscle- induced tensile forces into stabilising compressive forces that act across the fracture line, effectively clamping the acromion and maintaining alignment under physiological load.

[0036] In an alternative embodiment shown in Figure 3, the system 100 includes an elongate inferior suture button 116 defining multiple suture holes 117. This button 116 is positioned beneath the acromion 108, aligned with the insert apertures 112 for additional stability. The elongate inferior suture button 116 may distribute compressive force along the acromion’s undersurface, improving load distribution and reducing localised bone stress. In other variations, several shorter inferior suture buttons 116 may be used to achieve similar multi-point load sharing.

[0037] In a further embodiment, the elongate inferior suture button 116 may instead be implemented as multiple (such as three) individual inferior suture buttons arranged in spaced relation along the undersurface of the acromion. Each of the individual buttons defines one or more suture holes 117 aligned with respective insert apertures112 of the acromion plate 102. This arrangement provides modularity in button placement, allowing the surgeon to position each inferior button 118 independently to suit the patient’s anatomy and fracture pattern, thereby improving conformity, tension distribution, and ease of intraoperative adjustment compared with a single continuous button.

[0038] Through this configuration, the scapula plating system 100 provides a defined load-sharing construct in which the sutures, suture buttons, and acromion plate 102 function together to stabilise the acromion 108. The superior and inferior suture buttons 113, 114 cooperate to apply a compressive force across the acromion 108, counteracting separation at the fracture site. The sutures engaging the deltoid muscle or its tendon transfer tensile loading from the deltoid through the plate 102, thereby reducing direct stress on weakened bone. The anatomical curvature of the plate 102 and the widened lateral end 105 distribute load along the scapular contour and minimise localised stress concentration.

[0039] These embodiments differ from prior scapular fixation arrangements that employ sutures only as static tie elements in that the suture-button assembly and plate 102 act as a dynamic fixation mechanism that converts deltoid-induced tensile forces into compressive retention across the acromion 108, reducing the risk of loosening or failure at the bone-plate interface. The arrangement also allows intraoperative selection and placement of suture buttons 113, 114, 116 based on bone density and fracture pattern, providing controlled stabilisation of the acromion even in osteoporotic or thin bone.

[0040] In practice according to a preferred methodology, the scapula plating system 100 is positioned such that the medial end 103 is aligned with the spine 107 of the scapula 101 and the lateral end 105 is aligned with the acromion 108. The medial end 103 is secured using bone screws 109 inserted through the screw holes 104, establishing a rigid anchor point along the dense cortical structure of the scapular spine. This medial fixation serves as a stable base for transferring load from the lateral region of the plate. The lateral end 105, which interfaces with the acromion 108, is then secured using sutures threaded through the suture holes 106. Eachsuture is directed distally through the deltoid tendon or muscle fibres to create a continuous mechanical linkage between the contractile tissue and the plate. In some cases, the sutures are additionally passed through drilled apertures in the acromion 108 to achieve combined soft-tissue and bone fixation. Where greater load-bearing capacity is required, superior suture buttons 113 are inserted into the insert apertures 112, with corresponding inferior toggle buttons 114 deployed beneath the acromion to establish a clamping construct. Once tensioned and tied, the suture-button assembly generates a compressive stabilising force across the acromion while maintaining secure coupling to the deltoid.

[0041] This surgical configuration establishes a hybrid load-sharing construct in which the deltoid-generated tensile force is redirected through the sutures into the acromion plate 102, rather than being transmitted directly to the acromion. The plate distributes the transmitted load longitudinally and medially toward the scapular spine 107, which provides a stronger cortical anchor. This redistribution of stress reduces the likelihood of screw pull-out and localised strain in thin or osteoporotic bone, maintaining fixation integrity under cyclic muscular loading. Controlled adjustment of suture tension allows optimisation of compressive force across the fracture while preserving physiological deltoid excursion and shoulder biomechanics.

[0042] Figure 5 illustrates an embodiment in which the plate 102 exhibits multiple suture holes 106 positioned along both the posterior edge 110 and lateral edge 111 of the lateral end 105, thereby accommodating engagement of the posterior and lateral deltoid fibres that generate the greatest tensile forces during shoulder abduction. This orientation permits multi-vector tensioning and improved modulation of deltoid loading. The insert apertures 112 are arranged to accept superior suture buttons 113 positioned along the plate’s longitudinal axis, while the surrounding suture holes 106 permit supplemental fixation through adjacent soft tissue or bone.

[0043] The anatomical curvature of the acromion plate 102, as shown in Figure 5, conforms closely to the scapular surface, maintaining intimate contact and ensuring even stress distribution. The lateral end 105 is widened to increase the available surface area for suture placement and to distribute compressive forces transmittedthrough the suture-button assembly. This geometry, combined with the absence of bone screws in the lateral region, significantly reduces the incidence of localised bone failure and allows the construct to remain stable despite cyclical deltoid loading.

[0044] Through this hybrid fixation methodology, the scapula plating system 100 delivers superior biomechanical stability compared with conventional acromion plating techniques. By coupling the deltoid directly to the plate, the system achieves dynamic load sharing, sustained compression across the fracture, and improved fixation reliability even in osteoporotic bone. The result is a mechanically resilient construct that supports natural shoulder movement while promoting effective bone healing and reducing the risk of fixation failure.

[0045] The foregoing description, for purposes of explanation, used specific nomenclature to provide a thorough understanding of the invention. However, it will be apparent to one skilled in the art that specific details are not required in order to practise the invention. Thus, the foregoing descriptions of specific embodiments of the invention are presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the invention to the precise forms disclosed as obviously many modifications and variations are possible in view of the above teachings. The embodiments were chosen and described in order to best explain the principles of the invention and its practical applications, thereby enabling others skilled in the art to best utilize the invention and various embodiments with various modifications as are suited to the particular use contemplated. It is intended that the following claims and their equivalents define the scope of the invention.

Claims

Claims1. A scapula plating system for fixing an acromion fracture in a scapula, the system comprising: an elongate acromion plate having a medial end defining a plurality of bone screw holes and a lateral end defining a plurality of suture holes, wherein the medial end is configured for attachment to a spine of the scapula by bone screws extending through the bone screw holes, and wherein the lateral end is configured for attachment to an acromion of the scapula by sutures extending through the suture holes and also engaging directly with at least one of a deltoid muscle or a tendon of the deltoid muscle, such that tensile loading generated by the deltoid muscle is transmitted through the sutures to the acromion plate to reduce dependence on bone fixation at the acromion.

2. The scapula plating system of claim 1 , wherein the lateral end is free of bone screws.

3. The scapula plating system of claim 1 , wherein the lateral end is wider than the medial end.

4. The scapula plating system of claim 1 , wherein the acromion plate has anatomical curvature conforming to the scapula in a transverse plane.

5. The scapula plating system of claim 1 , wherein the medial end comprises at least five bone screw holes.

6. The scapula plating system of claim 1 , wherein the lateral end comprises at least seven suture holes.

7. The scapula plating system of claim 1 , wherein the suture holes are located along an edge of the lateral end.

8. The scapula plating system of claim 7, wherein the suture holes are located along both a posterior edge and a lateral edge of the lateral end.

9. The scapula plating system of claim 7, wherein the suture holes are not located along an anterior edge of the lateral end.

10. The scapula plating system of claim 1 , wherein the lateral end defines insert apertures for receiving superior suture buttons.11 . The scapula plating system of claim 10, further comprising superior suture buttons engaged within the insert apertures.

12. The scapula plating system of claim 11 , wherein each superior suture button comprises a pair of suture holes through which the sutures are tied.

13. The scapula plating system of claim 10, wherein the insert apertures are arranged in a row along an elongate axis defined by the acromion plate.

14. The scapula plating system of claim 10, further comprising an inferior suture button configured for placement beneath the acromion and tied to the superior suture buttons by the sutures.

15. The scapula plating system of claim 14, wherein the inferior suture button comprises a plurality of suture holes aligned with the insert apertures of the acromion plate.

16. The scapula plating system of claim 14, wherein the sutures extend through apertures formed in the acromion to interconnect the superior and inferior suture buttons.

17. The scapula plating system of claim 16, wherein the superior and inferior suture buttons cooperate to apply a compressive clamping force across the acromion.

18. A method of fixing an acromion fracture in a scapula, comprising: positioning a scapula plating system according to claim 1 such that the medial end is aligned with a spine of the scapula and the lateral end is aligned with an acromion of the scapula; inserting bone screws through the bone screw holes in the medial end to secure the medial end to the spine; and threading sutures through the suture holes in the lateral end and engaging the sutures with at least one of a deltoid muscle or a tendon of the deltoid muscle such that tensile loading generated by the deltoid muscle is transmitted through the sutures to the acromion plate to reduce dependence on bone fixation at the acromion.

19. The method of claim 18, further comprising passing the sutures through apertures in the acromion, securing superior suture buttons within insert apertures of the acromion plate, and tying the sutures to the superior suture buttons.

20. The method of claim 19, further comprising locating at least one inferior suture button beneath the acromion and tying the sutures between the inferior suture button and the superior suture buttons so as to apply a compressive clamping force across the acromion.

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