Clavicle Fracture Fixation: An Intraoperative Masterclass in Plate Osteosynthesis

Introduction and Epidemiology

As academic orthopedic surgeons and educators, our discourse on clavicular plate fixation must transcend rudimentary descriptions, delving into the nuanced biomechanics, surgical exigencies, and evidence-based outcomes that define contemporary management. The clavicle, often underestimated in its structural and functional significance, presents unique challenges in fracture care, with operative intervention increasingly recognized as a vital strategy for optimizing patient recovery and preventing debilitating sequelae.

Displaced, comminuted fractures of the clavicle are recognized as injuries carrying a substantial risk for nonunion and malunion, outcomes that can profoundly impair shoulder function and patient quality of life. Historically, the management of clavicle fractures leaned heavily towards non-operative treatment, even for significantly displaced patterns, predicated on the perception of excellent healing potential and satisfactory functional outcomes. However, a growing body of literature, including prospective randomized controlled trials, has challenged this paradigm, highlighting superior functional outcomes, lower rates of symptomatic malunion, and reduced nonunion rates with surgical intervention in specific fracture patterns. This evolution has solidified the role of open reduction and internal fixation (ORIF) with a plate and screws as a robust treatment option for appropriate indications.

The clavicle is the most commonly fractured bone in the upper extremity, accounting for approximately 2.6% to 5% of all adult fractures and 35% to 44% of shoulder girdle injuries. Diaphyseal (midshaft) fractures constitute the vast majority, representing 70% to 80% of all clavicular fractures. While non-operative management remains the standard for many non-displaced or minimally displaced fractures, the overall nonunion rate for diaphyseal clavicle fractures is reported to be approximately 4.5% in the broader literature, but can be significantly higher in specific high-risk cohorts. This rate escalates considerably with certain risk factors, such as initial shortening greater than 2 centimeters, completely displaced (off-ended) fracture fragments, severe comminution, advanced patient age, and tobacco use, necessitating a clear understanding of indications for operative intervention.

Surgical Anatomy and Biomechanics

The clavicle and scapula form a crucial link in the shoulder girdle, tightly integrated through the robust coracoclavicular and acromioclavicular ligaments. This complex connects the axial skeleton to the upper extremity, facilitating a wide range of motion and force transmission. Uniquely present in brachiating animals, the clavicle plays an indispensable role in maintaining the upper limb's position away from the trunk, thereby enhancing the global positioning and versatility of the limb.

The clavicle is descriptively named for its characteristic S-shaped curvature, featuring an apex anteromedially and another posterolaterally, reminiscent of the musical symbol clavicula. The larger, medial curvature is particularly significant, as it strategically widens the space for the passage of critical neurovascular structures originating from the neck and traversing into the upper extremity via the costoclavicular interval. This anatomical feature underscores the importance of precise surgical technique to avoid iatrogenic injury.

Structurally, the clavicle is composed predominantly of dense trabecular bone, notably lacking a well-defined medullary canal, which distinguishes it from many other long bones and influences reaming and intramedullary fixation strategies. Its cross-sectional morphology undergoes a gradual transformation along its length. A flat lateral aspect transitions into a more tubular midportion, which then expands into a prismatic medial end. This variability in cross-sectional geometry dictates appropriate plate contouring and screw trajectory.

The clavicle is subcutaneous throughout its length, making it a prominent aesthetic component of the neck and upper chest contour. This superficial position, while making it palpable and accessible for surgical intervention, also predisposes it to direct trauma and complicates soft tissue coverage following internal fixation. Furthermore, the supraclavicular nerves branch over the superior aspect of the clavicle, rendering them highly susceptible to iatrogenic injury during surgical approaches, which can result in problematic anterior chest wall numbness.

Biomechanically, the clavicle acts as a critical strut. When fractured, predictable deforming forces dictate the displacement pattern. The sternocleidomastoid muscle exerts a strong superior and posterior pull on the medial fragment. Conversely, the lateral fragment is drawn inferiorly by the weight of the upper extremity and pulled medially by the pectoralis major and latissimus dorsi muscles. This antagonistic muscular pull creates the classic displaced midshaft clavicle presentation: a shortened, translated fracture with the medial fragment superiorly displaced. Understanding these deforming forces is critical for achieving and maintaining anatomic reduction during osteosynthesis.

Indications and Contraindications

The decision to proceed with operative management of a clavicle fracture requires a meticulous risk benefit analysis, weighing the inherent risks of surgery against the probability of nonunion, malunion, and persistent functional deficit with conservative care. The Canadian Orthopaedic Trauma Society (COTS) and subsequent meta-analyses have provided robust frameworks guiding these clinical decisions.

Absolute indications for immediate surgical intervention are relatively rare but critical to identify. These include open fractures, fractures associated with neurovascular compromise (such as subclavian artery injury or progressive brachial plexopathy), and severe skin tenting that threatens the integrity of the soft tissue envelope. "Floating shoulder" injuries, characterized by ipsilateral fractures of the clavicle and the scapular neck, frequently warrant operative fixation of the clavicle to restore the suspensory strut of the shoulder girdle, although this remains a topic of nuanced debate depending on the degree of glenopolar angle alteration.

Relative indications encompass a broader spectrum of displacement patterns that portend a high risk of nonunion or symptomatic malunion. Shortening greater than 1.5 to 2.0 centimeters, 100% displacement without cortical contact (off-ended fractures), Z-type comminution, and polytrauma scenarios where early mobilization of the upper extremity is requisite for overall rehabilitation are strong relative indications. Patient-specific factors, such as high-demand athletic or occupational requirements, also heavily influence the decision matrix.

Contraindications to surgical fixation include active local or systemic infection, severe medical comorbidities precluding general anesthesia, and non-displaced or minimally displaced fractures where the risk of surgical morbidity (infection, hardware prominence, nerve injury) clearly outweighs the negligible risk of nonunion.

Pre Operative Planning and Patient Positioning

Thorough preoperative planning is paramount for successful clavicular osteosynthesis. Standard radiographic evaluation must include an anteroposterior (AP) view and a 15 to 20-degree cephalad tilt view. The cephalad view removes the superimposition of the thoracic cage and provides a true orthogonal assessment of superior-inferior displacement. In cases of significant comminution, medial or lateral end involvement, or suspected intra-articular extension into the acromioclavicular or sternoclavicular joints, a computed tomography (CT) scan with 3D reconstructions is highly recommended to accurately delineate fragment morphology and plan screw trajectories.

Implant selection should be tailored to the fracture pattern and patient anatomy. Pre-contoured locking plates (typically 3.5mm or 2.7mm/3.5mm hybrid systems) have largely superseded dynamic compression plates due to their anatomical fit, which minimizes the need for intraoperative bending, thereby preserving the structural integrity of the implant. The choice between superior and anteroinferior plate placement depends on surgeon preference and fracture morphology. Superior plating provides optimal biomechanical resistance to the primary inferior bending forces exerted by the weight of the arm. However, anteroinferior plating utilizes longer screws in the AP plane, poses less risk of hardware prominence, and directs drills away from the underlying neurovascular bundle.

Patient positioning is typically performed in the beach chair (semi-Fowler) position or supine with a bump placed between the scapulae to allow the shoulder girdle to fall posteriorly, aiding in the reduction of the shortened and anteriorly translated lateral fragment. The head should be turned away from the operative side, and the entire forequarter must be prepped and draped free to allow intraoperative manipulation of the arm, which is crucial for achieving reduction. Fluoroscopy should be brought in from the contralateral side or the head of the bed, ensuring unobstructed AP and cephalad views can be obtained prior to incision.

Detailed Surgical Approach and Technique

The surgical execution of clavicular plate fixation requires precise soft tissue handling, strategic reduction maneuvers, and rigid osteosynthesis to foster secondary or primary bone healing depending on the fracture pattern.

Incision and Superficial Dissection

The surgical incision is classically made along the anterior border of the clavicle, centered over the fracture site. Alternatively, an incision placed slightly inferior to the clavicle within Langer's lines can yield a more cosmetically acceptable scar, though it necessitates a superior soft tissue flap.

During the superficial dissection, meticulous attention must be paid to the supraclavicular nerves. These intermediate branches of the cervical plexus emerge deep to the platysma and cross the clavicle to provide sensation to the anterior chest wall. Whenever feasible, these branches should be identified, mobilized, and protected using vessel loops. Transection or aggressive retraction can lead to painful neuromas or a bothersome patch of anesthesia over the anterior deltoid and superior chest.

Deep Dissection and Fracture Exposure

Deep dissection proceeds through the platysma and the clavipectoral fascia. The periosteum should be incised sharply along the mid-axis of the clavicle. In simple fracture patterns (OTA/AO Type A or B), a subperiosteal dissection is performed to expose the fracture ends, taking care not to strip the periosteum excessively, which would devascularize the bone and impair healing.

In highly comminuted fractures (OTA/AO Type C), a "biologic" or bridge plating technique is preferred. The comminuted butterfly fragments should be left undisturbed within their soft tissue envelope to preserve their blood supply. Dissection is limited to the proximal and distal main fragments where the plate will be anchored.

Fracture Reduction Techniques

Reduction of the midshaft clavicle fracture must overcome the deforming forces of the sternocleidomastoid and pectoralis muscles. Direct manipulation of the arm (abduction, external rotation, and upward pressure on the elbow) assists in restoring length and alignment. Pointed reduction forceps (Weber clamps) can be applied to the main fragments.

For oblique fracture patterns, an independent lag screw (typically 2.7mm or 3.5mm) should be placed perpendicular to the fracture plane to achieve interfragmentary compression. This converts the construct into a load-sharing device, significantly enhancing construct rigidity. If the fracture geometry does not permit an independent lag screw, compression can be achieved dynamically through the plate using eccentrically placed non-locking screws.

Plate Application and Fixation

The pre-contoured plate is applied to the superior or anteroinferior surface of the clavicle. Superior placement requires careful attention to screw length, as over-penetration inferiorly directly threatens the subclavian vessels and brachial plexus. A depth gauge must be used meticulously, and bi-cortical purchase is standard, though uni-cortical locking screws may be utilized in specific osteoporotic or highly comminuted scenarios to avoid neurovascular injury.

A minimum of three bi-cortical screws (six cortices) on each side of the fracture is the biomechanical standard for adequate fixation, though four screws per side are preferred in comminuted or osteoporotic bone. In bridge plating constructs for comminution, the plate should span the zone of comminution, utilizing locking screws in the main proximal and distal fragments to create a fixed-angle construct that maintains length, alignment, and rotation while secondary bone healing occurs via callus formation.

Prior to final tightening, fluoroscopic verification in both AP and cephalad views is mandatory to confirm anatomic reduction, appropriate plate positioning, and accurate screw length. The wound is irrigated, and the clavipectoral fascia and platysma are closed in distinct layers to cover the hardware and optimize the cosmetic outcome of the skin closure.

Complications and Management

Despite high union rates associated with operative fixation, complications can and do occur. Surgeons must be adept at recognizing and managing these issues to optimize final outcomes.

Hardware prominence is the most frequently reported complication, particularly with superior plating in thin individuals. The subcutaneous nature of the clavicle means that even low-profile plates can cause irritation from backpack straps or seatbelts. Symptomatic hardware removal is a viable option, but should strictly be delayed until at least 12 to 18 months post-operatively to ensure complete radiographic and clinical consolidation of the fracture, mitigating the risk of re-fracture through empty screw holes.

Infection rates following clavicle ORIF are generally low (1-2%) but represent a severe complication. Superficial infections can often be managed with oral antibiotics. Deep infections require operative debridement, irrigation, and potentially hardware removal if the fracture has healed. If the fracture is unhealed, the hardware should be retained if stable, and culture-directed suppressive intravenous antibiotics initiated until union is achieved.

Nonunion, defined as a lack of radiographic progression of healing at 6 months, occurs in approximately 1-5% of operatively managed cases. Risk factors include inadequate fixation, infection, smoking, and severe initial comminution. Management of an aseptic nonunion requires revision ORIF. This typically involves removal of broken or loose hardware, aggressive debridement of the nonunion site down to bleeding bone, opening of the medullary canals, rigid fixation with a new plate (often utilizing a longer plate or dual plating techniques), and the application of autologous bone graft (typically from the iliac crest) to provide osteoinductive and osteoconductive stimulation.

Post Operative Rehabilitation Protocols

Rehabilitation following clavicular plate fixation is phased, balancing the need to protect the osteosynthesis construct with the imperative to prevent shoulder stiffness and adhesive capsulitis.

Phase I (0 to 2 weeks post-operative) focuses on soft tissue healing and pain control. The patient is placed in a simple sling for comfort. Absolute immobilization is unnecessary and detrimental; patients are encouraged to perform immediate pendulum exercises, as well as active range of motion of the elbow, wrist, and hand to prevent distal edema and stiffness.

Phase II (2 to 6 weeks post-operative) initiates progressive shoulder mobilization. Passive range of motion (PROM) and active-assisted range of motion (AAROM) are introduced, typically limiting forward elevation to 90 degrees and external rotation to neutral to avoid excessive rotational torque on the healing clavicle. Isometrics for the deltoid and rotator cuff can be safely initiated.

Phase III (6 to 12 weeks post-operative) begins once clinical and radiographic evidence of early callus formation is observed. The sling is completely discontinued. Active range of motion (AROM) is advanced in all planes. Progressive isotonic strengthening of the rotator cuff, deltoid, and periscapular stabilizers is integrated.

Phase IV (12+ weeks post-operative) focuses on a return to baseline function. Once radiographic union is confirmed (bridging callus on three of four cortices across orthogonal views), patients may return to heavy labor, contact sports, and advanced athletic activities. Full, unrestricted strength and dynamic stability of the shoulder girdle are the ultimate goals of this final phase.

Summary of Key Literature and Guidelines

The paradigm shift toward operative management of displaced midshaft clavicle fractures is anchored in landmark prospective literature. The Canadian Orthopaedic Trauma Society (COTS) published a pivotal multicenter randomized clinical trial in 2007 comparing non-operative management to plate fixation for completely displaced midshaft fractures. The study demonstrated that operative fixation resulted in significantly improved functional outcomes (DASH and Constant scores), a lower rate of nonunion (2% vs. 15%), and a lower rate of symptomatic malunion compared to conservative care.

Subsequent trials by Robinson et al. corroborated these findings, particularly in young, active patients, noting that open reduction and internal fixation significantly reduced the risk of nonunion and provided faster functional recovery. However, these studies also highlighted the trade-off of surgical intervention, specifically the risk of hardware-related complications and the frequent need for secondary operations for hardware removal.

Recent literature has also investigated plate positioning. Altamimi et al. and other biomechanical studies have compared superior versus anteroinferior plating. While superior plating offers a higher moment of inertia against inferior bending forces, anteroinferior plating has been shown to be clinically equivalent regarding union rates while demonstrating a statistically significant reduction in symptomatic hardware prominence and the subsequent need for implant removal.

Current consensus guidelines from the Orthopaedic Trauma Association (OTA) and the American Academy of Orthopaedic Surgeons (AAOS) support a shared decision-making model. While non-operative management remains appropriate for minimally displaced fractures and patients with low functional demands or high surgical risks, operative fixation with pre-contoured plates is strongly recommended for completely displaced fractures, fractures with significant shortening (>2cm), and in patients requiring expedited return to high-demand activities. The academic surgeon must synthesize this literature, applying it judiciously to the individual patient's anatomical and functional presentation to optimize outcomes and mitigate the risk of nonunion.

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