Operative Management of Clavicular Malunions: A Comprehensive Surgical Guide

Introduction to Clavicular Malunion

Historically, the prevailing orthopedic dogma dictated that the vast majority of clavicle fractures could be treated nonoperatively, with the expectation that they would heal reliably and that any resulting deformity would be well-tolerated by the patient. While it remains true that many clavicular malunions cause no significant functional limitations, contemporary outcome studies have unequivocally demonstrated that a distinct subset of patients will develop debilitating symptoms.

In these patients, malunion of the clavicle—characterized by substantial shortening, angular deformity, and translation—results in profound functional deficits and chronic pain. The modern orthopedic surgeon must possess a deep understanding of shoulder girdle biomechanics to identify which malunions require surgical intervention and to execute complex corrective osteotomies that restore native anatomy and scapulothoracic kinematics.

Pathoanatomy and Biomechanics

The clavicle acts as the sole osseous strut connecting the axial skeleton to the upper extremity. It functions to hold the shoulder out from the chest, maximizing the mechanical advantage of the shoulder musculature and protecting the underlying neurovascular bundle.

The Biomechanics of Shortening and Deformity

When a clavicle fracture heals with significant overlap, the resulting shortening alters the resting position of the scapula.
* Thresholds of Dysfunction: Biomechanical and clinical studies have established that shortening of 15 mm or more frequently causes discomfort and dysfunction of the shoulder girdle. Furthermore, 20 mm of shortening following the closed treatment of displaced middle-third clavicular fractures is strongly associated with poor clinical outcomes.
* Kinematic Alterations: A cadaveric study demonstrated that clavicular shortening, particularly when combined with caudal displacement, leads to significant functional deficits in shoulder abduction and overhead motion.
* Glenoid Version and Scapular Rotation: Angular deformity and shortening directly alter the spatial orientation of the glenoid fossa. 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 affects glenohumeral mobility and scapular rotation, ultimately leading to secondary scapular winging.

Clinical Pearl: The "driven-in" or ptotic shoulder is the clinical hallmark of a severely shortened clavicular malunion. This resting posture places abnormal tension on the periscapular musculature, leading to the rapid fatigability and chronic pain frequently reported by these patients.

Clinical Presentation and Evaluation

Patients with symptomatic clavicular malunions present with a constellation of symptoms that can range from mild cosmetic dissatisfaction to severe neurological compromise.

Symptomatology

• Pain and Weakness: Chronic pain over the malunion site and periscapular region, accompanied by subjective weakness, particularly during overhead activities.
• Rapid Fatigability: Due to altered resting muscle lengths and compensatory scapular dyskinesia.
• Thoracic Outlet Syndrome (TOS): Hypertrophic callus formation, combined with inferior angulation and shortening, can compress the brachial plexus and subclavian vessels against the first rib.
• Mechanical Irritation: Difficulty wearing over-the-shoulder straps (e.g., backpacks, seatbelts, brassieres) due to the prominent bony deformity.
• Cosmetic Deformity: A visibly droopy, ptotic, or asymmetrical shoulder girdle.

Radiographic Evaluation

Standard radiographic evaluation should include:
1. Anteroposterior (AP) View: To assess superior/inferior displacement.
2. 15- to 30-Degree Cephalic Tilt View: To accurately assess anteroposterior translation and shortening.
3. Bilateral Panoramic Views: To compare the injured clavicle's length to the contralateral normal side.
4. Computed Tomography (CT): A CT scan with 3D reconstructions is mandatory for preoperative planning. It allows for precise measurement of shortening, angular deformity, and the assessment of the hypertrophic callus in relation to the thoracic outlet.

Indications and Contraindications for Surgery

The decision to proceed with corrective osteotomy and plate fixation must be carefully weighed, as the procedure is technically demanding and carries inherent risks. Surgery is never indicated for cosmesis alone.

Indications for Corrective Osteotomy

According to the criteria established by McKee et al. and other modern investigators, surgical intervention is indicated for patients who have failed at least 6 to 12 months of conservative management and present with:
* Chronic, debilitating pain and weakness.
* Thoracic outlet syndrome secondary to callus compression.
* Radiographic Criteria:
* Substantial shortening (strictly > 1 cm, but usually 2 to 3 cm).
* Angular deformity greater than 30 degrees.
* Translation greater than 1 cm.

Contraindications

• Absolute: Active infection, inadequate soft tissue coverage, noncompliant patient, or asymptomatic malunion (regardless of radiographic appearance).
• Relative: Severely osteopenic or pathological bone, heavy tobacco use (unless the patient commits to cessation due to the high risk of nonunion).

Surgical Warning: Do not operate on a clavicular malunion based solely on radiographic parameters. The patient must have corresponding, refractory clinical symptoms. Prophylactic osteotomy to prevent future arthritis or dysfunction is not supported by current literature.

Surgical Management: Techniques and Approaches

The primary goal of surgery is to restore the native length and alignment of the clavicle, decompress the neurovascular structures if necessary, and achieve rigid internal fixation to promote predictable union.

Preoperative Planning

Utilize the 3D CT scan to determine the exact location and plane of the osteotomy. If the patient has a concurrent nonunion, preoperative planning must include provisions for autologous bone grafting (e.g., iliac crest bone graft).

Patient Positioning

1. Place the patient in the beach-chair position with the head secured and the neck in a neutral position.
2. Place a small bump between the scapulae to allow the shoulder girdle to fall posteriorly, aiding in the restoration of clavicular length.
3. Prep and drape the entire forequarter, allowing free manipulation of the arm. Prepare the ipsilateral iliac crest if bone grafting is anticipated.

Surgical Approach

1. Incision: Make an incision centered over the malunion, typically following Langer’s lines (slightly oblique to the clavicle) to optimize cosmetic healing, or directly over the superior border of the clavicle.
2. Nerve Protection: Meticulously dissect through the subcutaneous tissue and platysma. Identify and protect the branches of the supraclavicular nerve. Entrapment or transection of these nerves can lead to painful neuromas or distressing chest wall numbness.
3. Periosteal Elevation: Incise the clavipectoral fascia. Perform a subperiosteal dissection strictly limited to the area requiring osteotomy and plate application to preserve the vascular supply.

Technique 1: Corrective Osteotomy and Plate Fixation

This is the gold standard for symptomatic midshaft malunions.

1. Callus Resection: In patients with Thoracic Outlet Syndrome, carefully excise the posteroinferior hypertrophic callus. This bony prominence is often the primary culprit compressing the brachial plexus.
2. The Osteotomy: Using an oscillating saw, perform the osteotomy through the apex of the deformity. Depending on the malunion morphology, this may be a simple transverse osteotomy, an oblique osteotomy, or a closing/opening wedge osteotomy to correct angular deformity.
3. Mobilization: Release contracted soft tissues (such as the subclavius muscle) to allow for the restoration of length.
4. Reduction: Use pointed reduction forceps to manipulate the fragments. A laminar spreader can be gently utilized between the osteotomy ends to restore length.
5. Fixation: Apply a pre-contoured anatomical locking plate. Superior plating offers excellent biomechanical stability for bending forces, while anteroinferior plating allows for longer screw purchase and less hardware prominence. Ensure at least three (preferably four) bicortical screws are placed on each side of the osteotomy.
6. Bone Grafting: In the series by McKee et al., intercalary bone grafts were not routinely required for malunions. However, if an opening wedge osteotomy creates a significant structural void, or if there is an associated nonunion, autologous cancellous or structural iliac crest bone graft must be utilized.

Pitfall: Over-lengthening the clavicle beyond its native anatomical length can cause traction injuries to the brachial plexus. Always compare the restored length to the preoperative measurements of the contralateral normal clavicle.

Technique 2: Intramedullary Fixation

For specific patterns of malunion, Smekal et al. described corrective osteotomy utilizing an Elastic Stable Intramedullary Nail (ESIN).
* Advantages: This technique offers a minimally invasive approach, excellent cosmetic outcomes, and avoids the soft tissue stripping associated with extensive plating.
* Limitations: It provides less rotational stability than plate osteosynthesis and is generally reserved for simple angular deformities without the need for massive lengthening or structural grafting.

Management of Lateral Third Malunions

Malunions of the lateral third of the clavicle present a unique biomechanical challenge, often involving disruption of the coracoclavicular (CC) ligaments.
* If the malunion is associated with CC ligament incompetence, simple osteotomy is insufficient.
* The procedure must be combined with a CC ligament reconstruction (similar to the techniques described for chronic acromioclavicular joint dislocations), utilizing allograft or synthetic suspensory fixation devices to restore vertical stability to the lateral clavicle.

Postoperative Protocol and Rehabilitation

Successful outcomes depend heavily on a structured, phased rehabilitation program.

• Phase I (0 to 2 weeks): The arm is supported in a sling. Pendulum exercises and active range of motion of the elbow, wrist, and hand are initiated immediately. Passive forward elevation is limited to 90 degrees.
• Phase II (2 to 6 weeks): Sling is discontinued. Active-assisted range of motion is progressed. Scapular retraction and posture-correction exercises are emphasized to overcome the chronic "driven-in" posture.
• Phase III (6 to 12 weeks): Isotonic strengthening is initiated once radiographic evidence of early bridging callus is observed.
• Phase IV (3 to 6 months): Return to heavy labor and contact sports is permitted only after clinical and radiographic confirmation of solid union, typically around 12 to 16 weeks.

Clinical Outcomes and Complications

Efficacy of Surgical Intervention

The literature demonstrates high satisfaction rates following corrective osteotomy for properly selected patients. In the landmark study by McKee et al. involving 15 patients with an average preoperative shortening of 2.9 cm (range 1.6 to 4.0 cm):
* Functional scores improved in all patients.
* Of 12 patients with preoperative pain and weakness, symptoms resolved entirely in eight and improved in four.
* Of 11 patients with neurological complaints (TOS), symptoms resolved in seven, improved in three, and remained unchanged in only one.
* Cosmetic satisfaction was exceptionally high (12 of 13 patients satisfied).
* Overall, 14 of 15 patients were highly satisfied with the surgical outcome.

Persistent Impairment

Despite achieving solid osseous union, surgeons must counsel patients that a return to absolute baseline is not guaranteed. Rosenberg et al. noted that while solid union is reliably obtained after reduction, plating, and bone grafting, some patients remain functionally impaired. In their series, only 6 of 13 patients were able to return to their previous professional and recreational activities without restriction. This highlights the chronic soft-tissue and neuromuscular adaptations that occur during the malunion period, which may not be entirely reversible.

Complications

• Nonunion: The most significant complication, occurring in a small percentage of cases (e.g., one loss of fixation resulting in nonunion in the McKee series). Rigid fixation and meticulous soft tissue handling are paramount.
• Hardware Prominence: Due to the subcutaneous nature of the clavicle, plates frequently become symptomatic. Elective hardware removal is common (two plates were removed electively in the McKee series) but should be delayed until at least 12 to 18 months postoperatively.
• Infection and Wound Breakdown: Rare, but devastating. Careful layered closure over a suction drain (if dead space is present) mitigates this risk.
• Hypertrophic Scarring: The supraclavicular region is prone to widened or hypertrophic scars. Subcuticular closures and postoperative scar management protocols are recommended.

Conclusion

The management of clavicular malunions requires a nuanced understanding of shoulder biomechanics and rigorous patient selection. While nonoperative management remains the standard 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 and targeted neurovascular decompression, is a highly effective, albeit technically demanding, intervention that can reliably restore anatomy, alleviate pain, and return function to the compromised shoulder girdle.