Management of Clavicular Malunions: Corrective Osteotomy and Fixation

Comprehensive Introduction and Patho-Epidemiology

Historical Context and the Paradigm Shift

Historically, the vast majority of clavicle fractures were managed nonoperatively, governed by the prevailing dogma established by early orthopedic pioneers such as Neer and Rowe. This traditional perspective suggested that clavicular malunions were exceedingly well-tolerated by patients and caused no significant functional limitations, regardless of the degree of residual deformity. The overarching belief was that the robust compensatory mechanisms of the shoulder girdle would mitigate any biomechanical disadvantages imposed by a shortened or angulated clavicle. Consequently, surgical intervention was largely reserved for open fractures, severe neurovascular compromise, or impending skin necrosis.

However, the dawn of contemporary orthopedic literature, coupled with advanced biomechanical analyses and rigorous patient-reported outcome measures (PROMs), has catalyzed a profound paradigm shift. The landmark prospective randomized trials conducted by the Canadian Orthopaedic Trauma Society (COTS) unequivocally demonstrated that nonoperative management of displaced midshaft clavicle fractures yields higher rates of nonunion and symptomatic malunion than previously recognized. While many patients do achieve asymptomatic union despite some degree of radiographic deformity, a distinct and highly vocal subset of patients develops debilitating symptoms secondary to altered shoulder girdle mechanics.

This evolution in understanding has elevated the management of clavicular malunions from a mere academic curiosity to a critical component of modern shoulder reconstruction. Orthopedic surgeons now recognize that the clavicle is not merely an expendable bone, but a vital osseous strut essential for optimal upper extremity function. The contemporary consensus emphasizes that restoring native clavicular anatomy is paramount for patients who demand high-level functional performance, thereby establishing corrective osteotomy as a highly effective, albeit technically demanding, surgical solution.

Pathoanatomy of the Malunion

Malunion of the clavicle is characterized by a complex, three-dimensional deformity that typically involves shortening, inferior translation, and anterior rotation of the distal fragment relative to the proximal fragment. This pathoanatomy is dictated by the predictable deforming forces exerted by the regional musculature. The sternocleidomastoid muscle exerts a relentless superior and posterior pull on the medial fragment, while the weight of the unsupported upper extremity, combined with the inferomedial pull of the pectoralis major and latissimus dorsi, drives the lateral fragment inferiorly and medially.

The resulting deformity can result in profound functional deficits, chronic pain, and neurovascular compromise. The malunions that typically prove most disabling involve the medial or lateral thirds of the bone, though severe midshaft deformities are increasingly recognized as primary sources of significant morbidity. The classic "ptotic" or "driven-in" shoulder posture is a direct manifestation of this osseous collapse, leading to a cascade of secondary biomechanical failures throughout the entire upper quarter.

Furthermore, the formation of exuberant, hypertrophic fracture callus at the malunion site can exacerbate the pathoanatomy by encroaching upon the critical neurovascular structures traversing the costoclavicular space. This osseous prominence, particularly when projecting posteroinferiorly, acts as a space-occupying lesion that can compress the brachial plexus and subclavian vessels. Consequently, the pathoanatomy of a clavicular malunion is not limited to the bone itself but encompasses a holistic disruption of the surrounding soft-tissue envelope and neurovascular anatomy.

Epidemiology and Patient Demographics

Clavicle fractures account for approximately 2.6% to 4% of all adult fractures and up to 44% of all shoulder girdle injuries. Given the sheer volume of these injuries, even a modest rate of symptomatic malunion translates to a significant absolute number of affected patients. Epidemiological data suggest that symptomatic malunions most frequently occur following the nonoperative treatment of severely displaced, comminuted midshaft fractures (OTA/AO type 15-B2 and 15-B3).

Patients actively seeking surgical correction for clavicular malunions typically present at least one year post-injury, having exhausted extensive courses of conservative management, including targeted physical therapy, nonsteroidal anti-inflammatory drugs (NSAIDs), and activity modification. The demographic profile of these patients is heavily skewed toward young, active individuals, overhead athletes, and manual laborers whose occupational or recreational demands expose the functional deficits of their altered shoulder mechanics.

Interestingly, there is a growing recognition of symptomatic malunions in the aging population, particularly among individuals who maintain high levels of physical activity. In these older cohorts, the compensatory mechanisms of the periscapular musculature may fatigue more rapidly, unmasking the biomechanical detriment of the shortened clavicle. Regardless of age, the defining characteristic of this patient population is a profound dissatisfaction with their functional limitations and a strong desire to return to their pre-injury baseline.

Clinical Presentation and Symptomatology

The clinical presentation of a symptomatic clavicular malunion is multifaceted, reflecting the complex interplay between osseous deformity, muscular imbalance, and potential neurovascular irritation. Patients frequently report chronic, dull, aching pain localized to the periscapular region, the trapezius ridge, and the anterior chest wall. This pain is characteristically exacerbated by sustained overhead activities, repetitive lifting, or carrying heavy loads.

A hallmark symptom of significant clavicular shortening is rapid fatigability of the shoulder girdle. Patients often describe a subjective sense of weakness or a "dead arm" sensation after minimal exertion, a direct consequence of the altered length-tension relationship of the rotator cuff and periscapular musculature. Furthermore, the prominent malunion apex frequently causes localized soft-tissue irritation, rendering patients unable to comfortably wear heavy backpacks, seatbelts, or over-the-shoulder straps (such as brassiere straps).

In severe cases, the clinical presentation may be dominated by symptoms of secondary thoracic outlet syndrome (TOS). Inferior angulation and hypertrophic callus formation can compress the medial cord of the brachial plexus or the subclavian vessels. Patients may report paresthesias, numbness, or radicular pain radiating down the ulnar aspect of the forearm and hand. Vascular compression may manifest as claudication, cyanosis, or cold intolerance in the affected extremity. The cosmetic deformity of the "droopy" shoulder, while rarely the sole indication for surgery, is a frequent source of profound psychological distress and dissatisfaction for the patient.

Detailed Surgical Anatomy and Biomechanics

Osteology and the Strut Function

The clavicle is a unique, S-shaped tubular bone that functions as the sole osseous strut connecting the axial skeleton (via the sternoclavicular joint) to the appendicular skeleton of the upper extremity (via the acromioclavicular joint). Its complex morphology transitions from a robust, tubular cross-section in its medial third to a flattened, broad structure in its lateral third. This transitional zone in the middle third represents a biomechanical weak point, explaining why approximately 80% of all clavicle fractures occur in this region.

Functionally, the clavicle acts akin to a crane jib, suspending the scapula away from the thoracic wall and maintaining the optimal resting length of the shoulder girdle musculature. By projecting the glenohumeral joint laterally, the clavicle maximizes the mechanical advantage of the deltoid and rotator cuff, allowing for a vast and powerful arc of motion. Furthermore, the clavicle serves as a protective canopy for the underlying neurovascular bundle and the superior aspect of the pleural dome.

When a clavicular malunion occurs, this critical strut function is compromised. The loss of osseous length allows the scapula to collapse anteriorly and medially against the thoracic wall. This loss of the "crane jib" effect fundamentally alters the spatial orientation of the entire forequarter, transforming the clavicle from a rigid stabilizer into a collapsed, non-functional tether that actively impedes normal shoulder kinematics.

Ligamentous and Muscular Attachments

The clavicle serves as a critical anchor point for several major muscle groups, and understanding these attachments is paramount for both comprehending the deforming forces of a fracture and executing a safe surgical approach. Medially, the clavicular head of the sternocleidomastoid (SCM) originates from the superior surface, while the pectoralis major originates from the anterior border. Laterally, the trapezius inserts on the posterior border, and the anterior deltoid originates from the anterior border. The subclavius muscle lies along the inferior surface of the middle third, providing a modest dynamic stabilizing effect and serving as a soft-tissue buffer for the subclavian vessels.

The ligamentous anatomy is equally crucial, particularly the coracoclavicular (CC) ligament complex, comprising the conoid and trapezoid ligaments. These robust structures anchor the distal clavicle to the coracoid process of the scapula, providing primary resistance to superior displacement of the clavicle. In the setting of lateral third malunions, the integrity of the CC ligaments is often compromised, necessitating concurrent ligamentous reconstruction alongside corrective osteotomy to restore stability.

During surgical exposure, the surgeon must meticulously navigate these muscular attachments. Subperiosteal elevation must be precise to preserve the vascular supply to the bone while adequately exposing the malunion site. The delicate balance between achieving sufficient exposure for osteotomy and fixation and minimizing soft-tissue stripping is a critical determinant of successful osseous union following corrective surgery.

Neurovascular Proximity and Risk Zones

The surgical anatomy of the clavicle is fraught with peril due to its intimate relationship with vital neurovascular structures. The subclavian artery and vein, along with the trunks and divisions of the brachial plexus, traverse the costoclavicular space directly inferior to the middle third of the clavicle. The subclavian vein is the most vulnerable structure, lying anterior and inferior to the artery, separated only by the thin subclavius muscle and the clavipectoral fascia.

The supraclavicular nerves, branches of the superficial cervical plexus (C3-C4), descend over the clavicle to provide sensory innervation to the anterior chest wall and the skin overlying the deltoid. These nerves are highly variable in their branching patterns and are exquisitely sensitive to traction or transection. Iatrogenic injury during the surgical approach can result in painful neuromas or disabling areas of numbness, which are frequent sources of postoperative patient dissatisfaction.

A thorough understanding of these risk zones is mandatory for the operating surgeon. The "danger zone" lies directly posterior and inferior to the middle third of the clavicle. Penetration of drills, taps, or screws beyond the posterior cortex must be strictly controlled. The use of blunt retractors placed subperiosteally to protect the neurovascular bundle is an absolute requirement during osteotomy and drilling to prevent catastrophic iatrogenic injury.

Biomechanical Consequences of Deformity

When a clavicle fracture heals with significant shortening or angular deformity, the spatial orientation of the glenoid fossa is fundamentally altered, initiating a cascade of biomechanical failures. Shortening causes the scapula to protract, internally rotate, and tilt anteriorly. This resting malposition, termed scapular dyskinesia, forces the rotator cuff to operate at a profound mechanical disadvantage, leading to impingement syndromes, altered force vectors, and rapid muscular fatigue.

Altered glenoid version directly impacts glenohumeral mobility. As the scapula tilts anteriorly, the acromion is driven inferiorly, encroaching upon the subacromial space. This mechanical narrowing exacerbates rotator cuff impingement during forward elevation and abduction. Furthermore, the loss of clavicular length alters the tension of the trapezius and rhomboids, leading to chronic spasm and pain as these muscles struggle to support the weight of the ptotic upper extremity.

Clinical thresholds for symptomatic deformity have been rigorously investigated. Eskola et al., in a landmark study, demonstrated that clavicular shortening of 15 mm or more caused significant discomfort and dysfunction. Similarly, Hill et al. found that 20 mm of shortening following closed treatment of displaced middle-third fractures was highly correlated with poor clinical outcomes. While the modern consensus acknowledges that absolute measurements must be interpreted in the context of the patient's size and activity level, shortening greater than 2 cm in an active patient is universally recognized as a major risk factor for symptomatic malunion requiring surgical correction.

Exhaustive Indications and Contraindications

Establishing the Need for Intervention

The decision to proceed with corrective osteotomy for a clavicular malunion is highly nuanced and must be based on a meticulous synthesis of the patient's clinical symptoms, functional demands, and radiographic parameters. Surgery is never indicated based solely on an abnormal radiograph; the radiographic deformity must directly correlate with the patient's clinical complaints. The surgeon must establish that the patient's pain, weakness, or neurological symptoms are unequivocally derived from the altered mechanics or compressive effects of the malunion.

A critical component of this evaluation is ensuring that the patient has completed a rigorous, supervised trial of conservative management for a minimum of 6 to 12 months. This nonoperative phase should focus on periscapular strengthening, postural re-education, and targeted stretching to maximize compensatory mechanisms. Only when conservative measures have demonstrably failed, and the patient remains significantly disabled by their symptoms, should surgical intervention be entertained.

Furthermore, the surgeon must rule out concomitant shoulder pathology that could mimic or exacerbate the symptoms of a malunion. Concomitant rotator cuff tears, superior labral anterior-posterior (SLAP) lesions, or cervical radiculopathy must be evaluated and addressed. A diagnostic injection of local anesthetic into the subacromial space or the AC joint can be a valuable adjunct in isolating the primary source of the patient's pain.

Radiographic and Clinical Thresholds

The indications for surgery are defined by specific radiographic and clinical thresholds that have been validated in the orthopedic literature. The authors’ current radiographic criteria for considering osteotomy and plating include substantial shortening, significant angular deformity, and gross translation. These parameters are best quantified using advanced imaging modalities, comparing the affected side to the uninjured contralateral clavicle.

Clinically, the indications are driven by the severity and persistence of the patient's symptoms. Chronic pain and profound weakness that preclude the patient from returning to their pre-injury occupation or athletic pursuits are primary drivers for surgery. The presence of documented thoracic outlet syndrome secondary to osseous compression is an absolute indication for intervention, as progressive neurological deficit or vascular compromise can lead to irreversible damage.

It is imperative to note that surgery is rarely, if ever, indicated for cosmesis alone. While the restoration of normal shoulder contour is a frequent and highly appreciated secondary benefit of corrective osteotomy, the inherent risks of the procedure—including nonunion, infection, and neurovascular injury—far outweigh the benefits if the patient is functionally asymptomatic. Extensive preoperative counseling is required to align patient expectations with realistic surgical outcomes.

Indications and Contraindications Table

Pre-Operative Planning, Templating, and Patient Positioning

Advanced Imaging Modalities

Meticulous preoperative planning is the cornerstone of a successful clavicular osteotomy. Standard orthogonal radiographs, including bilateral anteroposterior (AP) and 15-degree cephalic/caudal tilt views, are mandatory. Bilateral imaging is absolutely crucial, as the uninjured contralateral clavicle serves as the patient's specific anatomical template. By comparing the injured side to the normal side, the surgeon can accurately quantify the exact degree of shortening, angulation, and translation.

However, standard radiographs are often insufficient for complex, three-dimensional deformities. A high-resolution Computed Tomography (CT) scan with 3D reconstructions is considered the gold standard for preoperative planning. The 3D models allow the surgeon to virtually rotate the clavicle, precisely delineating the plane of the malunion, the location of hypertrophic callus, and the exact morphology of any bone spikes threatening the neurovascular bundle.

Advanced imaging also allows for the assessment of bone quality and the presence of any occult nonunion within the malunion mass. The CT scan data can be utilized for advanced digital templating, and in highly complex cases, for the fabrication of 3D-printed patient-specific instrumentation (PSI) cutting guides, which ensure unparalleled accuracy during the execution of the osteotomy.

Digital Templating and Graft Selection

Digital templating is an essential step in determining the surgical strategy. The surgeon must virtually plan the osteotomy cut based on the original fracture morphology. Depending on the geometry of the malunion, an oblique osteotomy along the original fracture line (often termed a "take-down" osteotomy) or a single transverse osteotomy through the apex of the deformity may be required. The goal is to maximize the surface area for bone-to-bone contact while allowing for multi-planar correction.

A critical decision during the templating phase is determining the need for an intercalary structural bone graft. When the required lengthening exceeds 1.5 to 2.0 cm, acute distraction without a graft can leave a massive cortical defect, severely compromising the mechanical stability of the construct and placing undue tension on the brachial plexus. In these scenarios, the surgeon must plan for the harvest of an autologous tricortical iliac crest bone graft.

The dimensions of the required graft must be calculated preoperatively based on the templated length deficit. The graft not only provides immediate structural support to bridge the osteotomy gap but also supplies osteoinductive and osteogenic elements crucial for rapid osseous consolidation. While some authors advocate for the use of structural allografts to avoid donor site morbidity, the gold standard remains autologous iliac crest due to its superior biologic profile.

Anesthesia and Patient Positioning

The procedure is typically performed under general anesthesia, often supplemented with an interscalene regional nerve block to provide robust postoperative analgesia. The patient is placed in the beach-chair position, with the head securely stabilized in a specialized headrest. The back of the bed is elevated to approximately 45 to 60 degrees, allowing optimal access to the superior aspect of the shoulder girdle.

A critical nuance of positioning is the placement of a small bump or rolled towel longitudinally between the scapulae. This maneuver allows the affected shoulder girdle to fall posteriorly, utilizing gravity to assist in the restoration of clavicular length and the correction of anterior scapular protraction. The entire forequarter, from the sternal notch to the fingertips, is prepped and draped free, allowing the surgeon to manipulate the arm through a full range of motion intraoperatively to assess reduction and hardware clearance.

If an intercalary bone graft is anticipated, the ipsilateral iliac crest must be prepped and draped simultaneously. The surgical team must ensure that the patient is securely strapped to the table, as significant force may be required during the distraction phase of the procedure. A sterile tourniquet is not utilized, necessitating meticulous hemostasis throughout the surgical approach.

Equipment and Implant Selection

The selection of appropriate instrumentation and implants is critical for achieving absolute stability at the osteotomy site. The surgeon must have access to a variety of fine oscillating saws, sharp osteotomes, and specialized distraction tools, such as articulating laminar spreaders or articulated tension devices. These tools are essential for safely executing the osteotomy and gradually stretching the contracted soft tissues to restore anatomical length.

Implant selection heavily favors pre-contoured, anatomically designed clavicle locking plates. These plates are engineered to match the complex S-shaped geometry of the clavicle, minimizing the need for intraoperative bending, which can weaken the implant. The surgeon must decide between superior and anteroinferior plate placement. Superior plating offers excellent biomechanical stability on the tension band side of the bone but carries a higher risk of postoperative hardware prominence.

Conversely, anteroinferior plating utilizes longer screws directed from anterior to posterior, providing excellent pullout strength and significantly reducing hardware irritation beneath the skin. However, anteroinferior placement requires a meticulous drilling trajectory to avoid penetrating the posterior cortex and injuring the underlying neurovascular bundle. The surgeon must have both plate designs available and select the optimal implant based on the specific morphology of the corrected clavicle.

Step-by-Step Surgical Approach and Fixation Technique

Incision and Superficial Dissection

The surgical approach begins with a meticulously planned skin incision. A transverse or slightly oblique incision is centered over the palpable apex of the malunion, typically following Langer's lines to optimize postoperative cosmetic healing. The incision must be of sufficient length to allow for unencumbered access to both the medial and lateral segments of the clavicle, as well as the anticipated site of the osteotomy.

Dissection proceeds sharply through the subcutaneous adipose tissue to expose the platysma muscle. The platysma is incised in line with the skin incision. It is at this superficial plane that the surgeon encounters the most critical soft-tissue structures of the approach: the supraclavicular nerves. These sensory branches traverse the surgical field from superior to inferior.

Meticulous, blunt dissection using a hemostat or surgical loupes is required to identify, mobilize, and protect these nerve branches. They should be gently retracted with vessel loops. Transection or aggressive traction on the supraclavicular nerves can lead to the formation of exquisitely painful neuromas and debilitating anterior chest wall numbness, which can overshadow an otherwise technically perfect osteotomy. Preservation of these nerves is an absolute priority.

Deep Exposure and Neurovascular Protection

Once the superficial nerves are protected, the underlying clavipectoral fascia is incised to expose the periosteum of the clavicle. Subperiosteal elevation is performed using a sharp Cobb elevator or a periosteal elevator. The elevation must be strictly limited to the area required for the osteotomy and plate application. Aggressive circumferential stripping of the periosteum devascularizes the bone, drastically increasing the risk of nonunion.

The most hazardous step of the exposure is the dissection along the posterior and inferior borders of the clavicle, where the subclavian vessels and brachial plexus lie in intimate proximity. The surgeon must maintain a strict subperiosteal plane. As the inferior border is cleared, the subclavius muscle is gently elevated.

CRITICAL STEP: Before any saw blade or drill bit is activated, a protective barrier must be placed between the deep surface of the clavicle and the neurovascular bundle. A malleable copper retractor or a blunt-tipped Hohmann retractor is carefully advanced subperiosteally along the posterior-inferior cortex. This retractor serves as a physical shield, ensuring that any over-penetration by surgical instruments impacts the metal retractor rather than the catastrophic alternative of lacerating the subclavian vein.

Osteotomy Execution and Deformity Correction

With the neurovascular structures meticulously protected, the osteotomy is executed. Based on the preoperative CT templating, the surgeon identifies the optimal plane for the cut. If the original fracture line is discernible and oblique, a "take-down" osteotomy along this plane is preferred, as it maximizes the surface area for subsequent healing. If the malunion is a consolidated, amorphous mass, a transverse or step-cut osteotomy through the apex of the deformity is performed.

A fine, sharp oscillating saw is used under continuous saline irrigation to prevent thermal necrosis of the bone. The cut is made deliberately and carefully, ensuring the saw blade does not plunge beyond the posterior cortex. Once the osteotomy is complete, sharp osteotomes and rongeurs are used to clear away hypertrophic callus and fibrous tissue. Any prominent posterior or inferior bony spikes that were compressing the brachial plexus must be meticulously resected to achieve complete neural decompression.

Deformity correction is achieved by applying a laminar spreader or a specialized articulated distraction tool between the medial and lateral fragments. Distraction must be performed gradually, allowing the chronically contracted soft tissues (particularly the subclavius and pectoralis major) to stretch. The goal is to restore the anatomical length, rotation, and alignment of the clavicle, visually confirming the correction by comparing the spatial relationship of the fragments to the preoperative plan.

Intercalary Bone Grafting and Plate Fixation

If the required lengthening exceeds 1.5 to 2.0 cm, an intercalary structural bone graft is mandatory. The surgeon measures the exact dimensions of the defect and harvests a precisely matched tricortical block from the ipsilateral anterior iliac crest. This graft is contoured to fit perfectly within the osteotomy gap, acting as a structural spacer and a potent biologic stimulus for healing.

Fixation is achieved using a pre-contoured, anatomically designed clavicle locking plate. The plate is positioned either superiorly or anteroinferiorly, based on the surgeon's preference and the patient's anatomy. The plate must be of sufficient length to allow for a minimum of three (preferably four or five) bicortical locking screws in both the proximal and distal main fragments.

Absolute stability is the biomechanical goal. If the osteotomy geometry allows, an independent interfragmentary lag screw should be placed across the osteotomy site (or through the plate) to achieve dynamic compression. If an intercalary graft is utilized, it must be compressed between the main fragments and incorporated into the fixation construct with at least one screw passing directly through the graft. Following final tightening, fluoroscopic imaging in orthogonal planes confirms the restoration of length, the accuracy of reduction, and the appropriate length of all screws.

Considerations for Lateral Third Malunions

Malunions involving the lateral third of the clavicle present a unique and formidable biomechanical challenge. These deformities frequently involve disruption or chronic attenuation of the coracoclavicular (CC) ligament complex. If a lateral malunion is symptomatic, performing a simple corrective osteotomy and plate fixation is often insufficient, as the underlying vertical instability of the lateral clavicle remains unaddressed due to the incompetent CC ligaments.

In these complex scenarios, the surgical strategy must parallel the management of chronic, high-grade acromioclavicular (AC) joint dislocations. The procedure involves a corrective osteotomy of the lateral clavicle, rigid plate fixation utilizing a specialized lateral clavicle plate (which features multiple small-diameter locking screws for the diminutive distal fragment), and concurrent reconstruction of the CC ligament complex.

CC ligament reconstruction is typically achieved using a robust, free tendon allograft (such as a semitendinosus graft) passed beneath the coracoid and through osseous tunnels in the clavicle, often augmented with a suspensory cortical button device. This combined approach restores both the osseous anatomy and the critical superior-inferior soft-tissue stability of the lateral clavicle, preventing secondary displacement and hardware failure during the rehabilitation phase.

Complications, Incidence Rates, and Salvage Management

Nonunion and Hardware Failure

Nonunion is the most devastating complication following corrective osteotomy for clavicular malunion, with reported incidence rates ranging from 2% to 7% in major series. Nonunion typically results from a failure to achieve absolute mechanical stability, inadequate biological environment (e.g., excessive periosteal stripping, failure to use bone graft when indicated), or patient noncompliance with postoperative restrictions. Active tobacco use is a profound risk factor, exponentially increasing the rate of osseous failure.

Hardware failure, including plate breakage or screw pullout, is almost always secondary to an underlying nonunion. The clavicle is subjected to immense, repetitive bending and torsional forces. If the osteotomy does not consolidate, the plate acts as a load-bearing device rather than a load-