Operative Management of Clavicular Malunions: A Comprehensive Surgical Guide

Comprehensive Introduction and Patho-Epidemiology

Historically, the prevailing orthopedic dogma, heavily influenced by the early teachings of Neer and Rowe, dictated that the vast majority of clavicle fractures could be treated nonoperatively. The traditional assertion was that these fractures would heal reliably with simple sling immobilization and that any resulting clinical deformity or radiographic malunion would be well-tolerated by the patient without significant long-term sequelae. This conservative paradigm persisted for decades, leading to a pervasive underappreciation of the biomechanical consequences of a shortened, angulated clavicle. However, while it remains true that many clavicular malunions cause no significant functional limitations and represent mere cosmetic variations, contemporary prospective outcome studies and advanced kinematic analyses have unequivocally demonstrated that a distinct and predictable subset of patients will develop debilitating, chronic symptoms.

In these symptomatic patients, malunion of the clavicle—typically characterized by substantial shortening, severe angular deformity, and inferior translation—results in profound functional deficits, rapid fatigability, and chronic regional pain. The modern orthopedic surgeon must possess a deep, nuanced understanding of shoulder girdle biomechanics to accurately identify which malunions cross the threshold from asymptomatic radiographic curiosities to true pathologic entities requiring surgical intervention. The shift in our understanding was largely driven by the Canadian Orthopaedic Trauma Society (COTS) and landmark investigations by Hill, McKee, and others, who documented that shortening greater than 15 to 20 millimeters following the closed treatment of displaced middle-third clavicular fractures is strongly associated with poor clinical outcomes, persistent weakness, and patient dissatisfaction.

The patho-epidemiology of clavicular malunion is intrinsically linked to the initial fracture pattern and the chosen modality of treatment. Displaced midshaft clavicle fractures (Robinson Type 2B) possess a high inherent risk of healing in a shortened and translated position due to the deforming forces of the regional musculature. The sternocleidomastoid muscle exerts a relentless superior pull on the medial fragment, while the weight of the arm and the contraction of the pectoralis major and latissimus dorsi pull the lateral fragment inferiorly and medially. When allowed to consolidate in this overlapping position, the resulting malunion fundamentally alters the resting position of the scapula. The execution of complex corrective osteotomies to restore native anatomy and normal scapulothoracic kinematics has therefore emerged as a critical, albeit technically demanding, procedure in the armamentarium of the upper extremity surgeon.

Detailed Surgical Anatomy and Biomechanics

Osseous and Soft Tissue Anatomy

The clavicle is a complex, S-shaped tubular bone that acts 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). Anatomically, it transitions from a robust, tubular cross-section medially to a flat, broad structure laterally. This transitional morphology, combined with the lack of medullary canal in the lateral third, dictates the biomechanical stress risers where fractures—and subsequent malunions—most commonly occur. The clavicle is enveloped by a dense muscular sleeve that dictates the displacement of fracture fragments and the ultimate morphology of a malunion. Medially, the sternocleidomastoid and pectoralis major exert opposing forces, while laterally, the deltoid and trapezius attachments provide dynamic stability. The subclavius muscle, lying on the inferior surface of the clavicle, often becomes contracted in the setting of a shortened malunion and must frequently be released during reconstructive procedures to allow for the restoration of native clavicular length.

Neurovascular Relations and the Thoracic Outlet

The intimate spatial relationship between the clavicle and the underlying neurovascular structures is of paramount importance when evaluating and operating on clavicular malunions. The brachial plexus, the subclavian artery, and the subclavian vein traverse the thoracic outlet directly posterior and inferior to the middle third of the clavicle. In the setting of a malunion, particularly one with significant inferior angulation and hypertrophic callus formation, the volume of the costoclavicular space is dramatically reduced. This osseous encroachment can mechanically compress the neurovascular bundle against the first rib, leading to secondary Thoracic Outlet Syndrome (TOS). Furthermore, the supraclavicular nerves, which branch from the cervical plexus (C3-C4), drape over the superior surface of the clavicle. These sensory nerves are highly susceptible to entrapment within the fracture callus or iatrogenic transection during surgical exposure, which can result in agonizing postoperative neuromas or distressing areas of chest wall anesthesia.

Biomechanics of Shortening and Scapular Dyskinesia

The biomechanical consequences of clavicular malunion extend far beyond the clavicle itself, profoundly affecting the entire shoulder girdle. The clavicle functions to hold the shoulder out from the chest wall, maximizing the mechanical advantage of the rotator cuff and periscapular musculature. When a clavicle fracture heals with significant overlap, the resulting shortening alters the resting position of the scapula, leading to a phenomenon clinically recognized as the "driven-in" or ptotic shoulder. Biomechanical and clinical studies have established that shortening of 15 millimeters or more frequently causes discomfort, while shortening approaching 20 millimeters is a critical threshold for severe dysfunction.

A specialized vector model has been devised to calculate the position of the glenoid fossa in relation to the clavicle. This model illustrates how medial and forward displacement of the shoulder girdle directly alters glenoid version, typically increasing anterior orientation. This kinematic alteration leads to significant functional deficits in shoulder abduction and overhead motion. The resting ptotic posture places abnormal, chronic tension on the periscapular musculature—specifically the trapezius, levator scapulae, and rhomboids—leading to the rapid fatigability, muscular spasm, and chronic pain frequently reported by these patients. Restoring the strut function of the clavicle through corrective osteotomy lateralizes the scapula, normalizes glenoid version, and restores the optimal resting length-tension relationship of the shoulder musculature.

Exhaustive Indications and Contraindications

The decision to proceed with corrective osteotomy and plate fixation for a clavicular malunion must be meticulously weighed. The procedure is technically demanding, carries inherent risks of neurovascular injury and nonunion, and requires a highly compliant patient. Surgery is never indicated for cosmesis alone; there must be a direct correlation between the patient's subjective functional deficits and the objective radiographic deformity.

According to the criteria established by modern investigators, surgical intervention is indicated only for patients who have failed an exhaustive trial of conservative management, typically lasting a minimum of 6 to 12 months. This nonoperative phase should include targeted physical therapy focusing on periscapular strengthening, postural correction, and dynamic stabilization of the scapula. If the patient remains highly symptomatic despite these measures, surgical reconstruction may be considered. The primary clinical indications include chronic, debilitating pain over the malunion site and periscapular region, profound subjective weakness during overhead activities, rapid fatigability due to altered resting muscle lengths, and symptoms of Thoracic Outlet Syndrome (TOS) secondary to hypertrophic callus compression.

Radiographically, the deformity must be substantial enough to explain the clinical symptomatology. While absolute numbers can be debated, widely accepted radiographic criteria for intervention include substantial shortening (strictly greater than 1 centimeter, but usually 2 to 3 centimeters in symptomatic patients), angular deformity greater than 30 degrees, and translation greater than 1 centimeter. Conversely, absolute contraindications include active or recent local infection, inadequate soft tissue coverage that would preclude safe plate coverage, a noncompliant patient who cannot adhere to strict postoperative rehabilitation, or an asymptomatic malunion regardless of how grotesque the radiographic appearance may be. Prophylactic osteotomy to prevent future glenohumeral arthritis or hypothetical dysfunction is not supported by current orthopedic literature.

Pre-Operative Planning, Templating, and Patient Positioning

Advanced Imaging and Digital Templating

Meticulous preoperative planning is the cornerstone of a successful clavicular malunion takedown. Standard radiographic evaluation should include an Anteroposterior (AP) view to assess superior/inferior displacement, a 15- to 30-degree cephalic tilt view to accurately assess anteroposterior translation and shortening, and bilateral panoramic views to compare the injured clavicle's length to the contralateral normal side. However, plain radiographs are insufficient for the complex three-dimensional understanding required for this surgery. A Computed Tomography (CT) scan with 3D reconstructions is mandatory. The CT scan allows for precise measurement of shortening, characterization of the angular deformity, and, critically, the assessment of the hypertrophic callus in relation to the thoracic outlet and underlying neurovascular structures.

Digital templating should be performed using the 3D CT data to determine the exact location, plane, and angle of the planned osteotomy. The surgeon must decide preoperatively whether a simple transverse osteotomy, an oblique osteotomy, or a complex closing/opening wedge osteotomy will be required to correct the multiplanar deformity. Furthermore, if the patient has a concurrent nonunion or if an opening wedge osteotomy is planned that will create a significant structural void, preoperative planning must include provisions for autologous bone grafting. The surgeon must template the size of the required intercalary graft and prepare for iliac crest bone harvesting.

Operating Room Setup and Patient Positioning

Proper patient positioning is critical to facilitate both the surgical exposure and the intraoperative reduction of the shoulder girdle. The patient is typically placed in the beach-chair position, with the backrest elevated to approximately 30 to 45 degrees. The head must be securely fixed in a neutral position using a specialized headrest or Mayfield tongs, ensuring that the cervical spine is neither hyperextended nor rotated, which could place undue traction on the brachial plexus.

A small bump (e.g., a rolled towel or intravenous fluid bag) is placed vertically between the scapulae. This allows the involved shoulder girdle to fall posteriorly, which significantly aids in the restoration of clavicular length during the reduction phase of the procedure. The entire forequarter, from the sternum to the mid-humerus, must be prepped and draped free, allowing the surgeon to manipulate the arm dynamically to assist with fracture reduction. If bone grafting is anticipated, the ipsilateral anterior iliac crest must be simultaneously prepped and draped in a sterile fashion. A sterile tourniquet is not applicable here, so meticulous hemostasis using electrocautery is essential throughout the procedure.

Step-by-Step Surgical Approach and Fixation Technique

Surgical Approach and Neuroma Prevention

The surgical incision must be planned carefully to optimize both exposure and cosmetic outcome. An incision centered over the apex of the malunion is utilized, typically following Langer’s lines (slightly oblique to the axis of the clavicle) to minimize scar hypertrophy, or placed directly over the superior border of the clavicle. Meticulous dissection through the subcutaneous tissue and the platysma muscle is performed. The surgeon must remain hyper-vigilant to identify, mobilize, and protect the branches of the supraclavicular nerve (medial, intermediate, and lateral branches). Entrapment in the plate or iatrogenic transection of these nerves is a leading cause of patient dissatisfaction, resulting in painful neuromas or distressing chest wall numbness. Once the nerves are protected, the clavipectoral fascia is incised. A subperiosteal dissection is then performed, strictly limited to the area requiring osteotomy and plate application, to preserve the tenuous periosteal vascular supply critical for subsequent bone healing.

Osteotomy and Callus Resection

The initial osseous step involves the careful resection of the hypertrophic callus, particularly in patients presenting with Thoracic Outlet Syndrome. The posteroinferior callus is often the primary culprit compressing the brachial plexus and subclavian vessels. This resection must be performed with extreme caution, utilizing small osteotomes, rongeurs, or a high-speed burr, while constantly protecting the underlying neurovascular bundle with a malleable retractor or a right-angle elevator.

Once the callus is cleared and the original fracture plane or apex of deformity is identified, the osteotomy is performed. Using a fine-toothed oscillating saw, the surgeon cuts through the apex of the malunion. Depending on the preoperative templating and the morphology of the malunion, this may be a simple transverse osteotomy to correct shortening, an oblique osteotomy to increase the surface area for healing, or an opening wedge osteotomy to correct severe angular deformity. Copious saline irrigation must be used during the saw cut to prevent thermal necrosis of the bone, which could precipitate a nonunion.

Reduction Techniques and Restoration of Length

Mobilization of the osteotomized fragments is often the most challenging aspect of the procedure due to chronic soft tissue contractures. The subclavius muscle and the inferior periosteum frequently require careful release to allow for the restoration of length. Pointed reduction forceps (Weber clamps) are applied to the medial and lateral fragments to manipulate them in three-dimensional space. A laminar spreader can be gently inserted between the osteotomy ends to distract the fragments and restore native length.

The surgeon must be cautious not to over-lengthen the clavicle beyond its native anatomical length, as this can cause acute traction injuries to the brachial plexus (supraclavicular neurapraxia). The restored length should be constantly compared to the preoperative measurements of the contralateral normal clavicle. The arm can be pushed superiorly and posteriorly by an assistant to help align the lateral fragment with the medial fragment, counteracting the deforming forces of the weight of the arm and the pectoralis major.

Plate Osteosynthesis and Bone Grafting

Once anatomical alignment and length are restored, rigid internal fixation is achieved using a pre-contoured anatomical locking plate. Superior plating offers excellent biomechanical stability against the primary bending forces exerted on the clavicle, while anteroinferior plating allows for longer screw purchase (due to the AP diameter of the clavicle) and results in less hardware prominence beneath the skin. The choice of plate position depends on the specific fracture morphology and surgeon preference.

A minimum of three, but preferably four, bicortical screws must be placed on each side of the osteotomy to ensure adequate construct rigidity. If an oblique osteotomy was performed, a lag screw can be placed across the osteotomy site prior to, or through, the neutralization plate to provide absolute stability. In cases where an opening wedge osteotomy creates a significant structural void, or if there is an associated nonunion with sclerotic bone ends, autologous bone grafting is mandatory. Cancellous graft from the iliac crest can be packed into small defects, while larger defects require an intercalary structural tricortical iliac crest bone graft to bridge the gap and provide mechanical support.

Management of Lateral Third Malunions

Malunions of the lateral third of the clavicle present a unique biomechanical challenge that differs significantly from midshaft deformities. These malunions often involve concurrent disruption or chronic incompetence of the coracoclavicular (CC) ligaments. If the malunion is associated with CC ligament incompetence, a simple osteotomy and plating will inevitably fail due to the massive deforming forces of the trapezius and the weight of the arm. In these complex scenarios, the corrective osteotomy must be combined with a CC ligament reconstruction. This is achieved utilizing techniques similar to those described for chronic acromioclavicular joint dislocations, employing allograft tissue (e.g., semitendinosus) or synthetic suspensory fixation devices (endobuttons) to restore vertical stability to the lateral clavicle and offload the osteosynthesis construct while it heals.

Complications, Incidence Rates, and Salvage Management

Despite meticulous surgical technique, the operative management of clavicular malunions is fraught with potential complications. The altered anatomy, scarred soft tissue envelope, and the necessity to stretch chronically contracted neurovascular structures make this a high-risk procedure that should be reserved for experienced shoulder and upper extremity surgeons.

Intraoperative and Early Postoperative Complications

Intraoperative complications primarily involve injury to the neurovascular structures. The subclavian vein is particularly vulnerable during the resection of posteroinferior callus or during the plunging of a drill bit. Meticulous technique and the use of drill stops are mandatory. Early postoperative complications include wound breakdown and infection. The supraclavicular region has a relatively thin soft tissue envelope, and the introduction of bulky hardware can compromise skin perfusion. Careful, layered closure over a suction drain (if significant dead space is present) mitigates this risk. Supraclavicular nerve neuropraxia or neuroma formation is common, occurring in up to 10-15% of cases, and can cause significant patient distress despite a radiographically perfect osteotomy.

Late Complications and Hardware Management

The most significant late complication is nonunion, which occurs in approximately 1% to 5% of corrective osteotomies. Nonunion is typically the result of inadequate mechanical fixation, thermal necrosis during the osteotomy, failure to utilize bone graft when indicated, or patient noncompliance (particularly tobacco use). Hardware prominence is an exceedingly common late complaint due to the subcutaneous nature of the clavicle. Plates frequently become symptomatic, particularly under backpack straps or seatbelts. Elective hardware removal is performed in 10% to 30% of patients but must be strictly delayed until at least 12 to 18 months postoperatively, and only after CT confirmation of solid, mature osseous union.

Salvage of the Failed Malunion Takedown

In the devastating event of a nonunion following a malunion takedown, salvage procedures are complex. The surgeon must rule out indolent infection (e.g., Cutibacterium acnes) through deep tissue cultures. Aseptic nonunions require revision open reduction and internal fixation, typically utilizing a longer, more robust plate (often orthogonal dual plating), combined with aggressive resection of the nonunion site and massive autologous bone grafting. In extreme cases of recalcitrant nonunion with massive bone loss, vascularized fibular autograft transfer may be the only viable salvage option to restore the shoulder strut.

Phased Post-Operative Rehabilitation Protocols

Successful functional outcomes following clavicular malunion takedown depend just as heavily on a structured, phased rehabilitation program as they do on the surgical execution. The chronically "driven-in" shoulder has undergone significant neuromuscular adaptation, and the patient must actively un-learn pathologic movement patterns.

• Phase I: Immediate Postoperative Period (0 to 2 weeks)
  The primary goal in this phase is the protection of the osteosynthesis construct and soft tissue healing. The arm is supported in a standard sling at all times, except for hygiene and exercises. Pendulum exercises and active range of motion of the elbow, wrist, and hand are initiated immediately to prevent distal stiffness. Passive forward elevation of the shoulder is strictly limited to 90 degrees to minimize rotational forces on the clavicle. Active shoulder motion is prohibited.
• Phase II: Early Mobilization (2 to 6 weeks)
  As soft tissue healing progresses, the sling is gradually discontinued, usually around the 4-week mark depending on patient comfort and hardware stability. Active-assisted range of motion is progressed, utilizing pulleys and wand exercises. A critical component of this phase is the initiation of scapular retraction and posture-correction exercises. The patient must consciously work to overcome the chronic ptotic posture and engage the trapezius and rhomboids to stabilize the scapula dynamically.
• Phase III: Strengthening and Functional Restoration (6 to 12 weeks)
  Isotonic strengthening is initiated only once radiographic evidence of early bridging callus is observed on follow-up radiographs (typically at the 6-week mark). Resistance band exercises for the rotator cuff and periscapular stabilizers are introduced. Range of motion should be pushed to achieve full, symmetric elevation and rotation. Closed kinetic chain exercises can be cautiously introduced to improve proprioception.
• Phase IV: Return to High-Level Activity (3 to 6 months)
  Return to heavy labor, overhead lifting, and contact sports is strictly prohibited until there is clinical (absence of pain at the osteotomy site) and radiographic (obliteration of the osteotomy lines on multiple views or CT scan) confirmation of solid union. This typically occurs around 12 to 16 weeks postoperatively. Patients must be counseled that maximal medical improvement, particularly regarding muscular endurance and the resolution of chronic dyskinesia, may take up to a full year.

Summary of Landmark Literature and Clinical Guidelines

The evolution of operative management for clavicular malunions is heavily anchored in several landmark clinical studies that have shaped modern orthopedic guidelines. The literature consistently demonstrates high satisfaction rates following corrective osteotomy, provided that patient selection is rigorous and surgical technique is flawless.

The seminal study by McKee et al. remains the gold standard reference for this procedure. In their prospective evaluation involving 15 patients with an average preoperative shortening of 2.9 centimeters (ranging from 1.6 to 4.0 centimeters), the results were transformative. Functional scores (DASH and Constant scores) improved significantly in all patients. Of the 12 patients presenting with preoperative pain and weakness, symptoms resolved entirely in eight and improved in four. Crucially, of the 11 patients with neurological complaints indicative of Thoracic Outlet Syndrome, symptoms resolved in seven, improved in three, and remained unchanged in only one. Cosmetic satisfaction was exceptionally high, and overall, 14 of the 15 patients were highly satisfied with their surgical outcome. This study definitively proved that restoring the anatomical length of the clavicle directly reverses the pathoanatomy of the ptotic shoulder.

However, subsequent literature, such as the series by Rosenberg et al., provides a necessary tempering of expectations. Rosenberg noted that while solid osseous union is reliably obtained after reduction, plating, and bone grafting, some patients remain functionally impaired. In their specific cohort, only a fraction of patients were able to return to their previous professional and recreational activities completely without restriction. This highlights a critical clinical guideline: surgeons must preoperatively counsel patients that while surgery is highly effective at alleviating severe pain and neurovascular compression, a return to absolute pre-injury baseline is not guaranteed. The chronic soft-tissue contractures, capsular adaptations, and neuromuscular dyskinesia that occur during the months or years of living with a malunion may not be entirely reversible, even with a perfectly executed osteotomy.

In conclusion, the management of clavicular malunions requires a nuanced, highly technical approach. While nonoperative management remains the standard of care for acute, minimally displaced fractures, the orthopedic surgeon must recognize the profound morbidity associated with severe shortening and angular deformity. Corrective osteotomy, combined with rigid plate osteosynthesis, targeted neurovascular decompression, and rigorous postoperative rehabilitation, is a highly effective intervention that can reliably restore anatomy, alleviate debilitating pain, and return critical function to the compromised shoulder girdle.