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Arthrosc Tech
Arthrosc Tech
Arthroscopy Techniques
2212-6287
Elsevier

S2212-6287(24)00152-X
10.1016/j.eats.2024.103043
103043
Technical Note
Shoulder
Surgical Technique for Management of Congenital Pseudarthrosis of the Clavicle
Da Silva Adrik B.S. adrik.dasilva@hsc.utah.edu
∗
Radtke Logan M.D.
Chalmers Peter M.D.
Department of Orthopaedics, University of Utah, Salt Lake City, Utah, U.S.A.
∗ Address correspondence to Adrik Z. Da Silva, B.S., Department of Orthopaedics, University of Utah, 590 Wakara Way, Salt Lake City, UT 84018, U.S.A. adrik.dasilva@hsc.utah.edu
30 5 2024
9 2024
30 5 2024
13 9 10304322 1 2024
2 4 2024
© 2024 The Authors
2024
https://creativecommons.org/licenses/by-nc-nd/4.0/ This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
Congenital pseudarthrosis of the clavicle is a rare phenomenon with multiple proposed causes. Surgical management is typically indicated either because of the cosmetic appearance of the irregularity or, less commonly, for pain, particularly in adolescent patients. Multiple surgical methods have previously described in the literature, which have raised concern owing to the persistently high rate of nonunion postoperatively. This article describes management of congenital pseudarthrosis of the clavicle with open reduction and internal fixation using a T-shaped iliac crest autograft.

Technique Video
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pmcCongenital pseudarthrosis of the clavicle (CPC) is a rare diagnosis, originally described in 1910, with recent estimates of only 200 cases described in the literature to date.1,2 The exact cause of CPC remains uncertain.3 Two prevailing theories have been proposed: One suggests a failure in fusion of the 2 ossification centers during the sixth week of intrauterine gestation,4 whereas the other points to anatomic irregularities that may contribute to subclavian artery pulsations prohibiting appropriate fusion, such as the presence of a cervical rib or an unduly elevated first rib.5 CPC most commonly is appreciated in the middle third of the right clavicle, which has strengthened the argument for the latter of the 2 theories.1,2,5,6

CPC is more common in female patients, with estimates showing a 25% to 80% increased incidence in female patients relative to male patients.2,7 Patients may receive the diagnosis in early childhood or further on as adolescents, typically presenting with a painless deformity or notable protrusion of the clavicle; however, pain may be appreciated as individuals begin increasing their activity levels and/or patients may note particular discomfort while wearing backpacks.1,2,8 Rare cases of thoracic outlet syndrome or brachial plexopathy have been reported in the setting of CPC as well.2,9 The indication and age for surgery are still debated, with no consensus in the literature; however, most surgeons agree that symptomatic patients with neurovascular compromise or functional impairment should undergo surgical intervention.9,10 Bone union rates with internal plate fixation have been reported to be 70% to 74%, with a systematic review showing similar healing rates with pinning.8,11,12

Owing to the high rate of nonunion after operative fixation of CPC, we herein describe a method of iliac crest autograft fixation to address this. Previous surgical techniques have described graft preparation with a bone block of similar dimensions to the existing clavicle deformity after resection of the pseudarthrosis. The technique presented in this article describes a method using a T-shaped autograft that provides significantly increased surface area for bone-to-bone healing.

Patient Evaluation, Imaging, and Indications

CPC is more common in female patients, with many patients receiving the diagnosis in childhood or adolescence. Physical examination often reveals a notable protrusion of the clavicle. The deformity may be painful on palpation or specifically with range of motion. Radiographs should be the first step in imaging and can reveal atrophic pseudarthrosis, as shown in Figure 1. If operative intervention is pursued, subsequent imaging should consist of a computed tomography scan, which can further exhibit pseudarthrosis of the clavicle, as shown in Figure 2. The indication and age for surgery are still debated; however, a symptomatic patient with neurovascular compromise or functional impairment should be considered a candidate for surgery on further discussion of risks and benefits with the patient.Fig 1 Preoperative anteroposterior (A) and anteroposterior cephalad (B) radiographic views of right clavicle showing atrophic pseudarthrosis of clavicle with sclerotic margins (indicated by white arrows). (deg, degrees.)

Fig 2 Preoperative computed tomography scans of right shoulder. Right clavicular pseudarthrosis (indicated by white arrow) is observed on axial (A) and coronal (B) computed tomography scans, as well as 3-dimensional reconstruction (C).

Surgical Technique

The patient is placed in the supine position, and the surgical procedure begins with iliac crest harvest; the operative procedure is shown in Video 1. An incision is made over the palpable iliac crest and carried down to the external oblique fascia for 4 cm, followed by dissection down to the crest. The fascia overlying the crest is released, and the muscle is recessed from a 3 × 1-cm area; then, an oscillating saw is used to resect a 3 × 1-cm square from the crest.

Once the graft is obtained, attention is directed to the clavicle. A 6-cm incision is made transversely overlying the palpable clavicle. Dissection is performed down to the clavicle, and the fascia overlying the clavicle is incised, revealing the pseudarthrosis site. The bone is circumferentially dissected in this location while care is taken to protect the underlying plexus. After dissection, an oscillating saw is used to excise the pseudarthrosis. This creates a 4-mm gap, depending on the size of the pseudarthrosis. The ends are drilled, and the anterior surface is burred to spur a healing surface. The iliac crest autograft is then cut into a T shape. The arms of the T in this case are just over 1 cm each, and the leg of the T is 7 mm wide and 1 cm long (Fig 3). This is shaped with an oscillating saw. The leg of the T is then wedged into the gap such that the arms contact the previously burred anterior surface (Fig 3). A 3.5-mm titanium, locking, anatomically contoured clavicle plate (Synthes) is bent to match the bone shape and is fixated using a standard compression technique. After plate fixation, the graft is fixated to the bone ends from anterior to posterior using 2.7-mm cortical screws. Thus, the graft is compressed at the endosteal surface with the plate and at the anterior surface using lag screws. Biplanar fluoroscopic views are obtained to confirm appropriate screw lengths, and the patient is placed in a sling and transferred to the postoperative unit. Radiographs obtained 4 months postoperatively show that all hardware is intact with progression to union (Fig 4).Fig 3 (A) Photograph of T-shaped iliac bone graft being cut with oscillating saw. (B) Photograph of graft in place in excised pseudarthrosis site of right clavicle (outlined in dotted black line).

Fig 4 (A, B) Four-month postoperative radiographs of right clavicle. The radiographs show that all hardware is intact without evidence of persistent nonunion of the right clavicle.

Discussion

CPC is a rare phenomenon usually diagnosed in early childhood or adolescence, characterized by a painless deformity or notable protrusion of the clavicle. Surgical management is controversial, with many proposed methods yielding a persistently high rate of nonunion postoperatively. This article describes management of CPC with open reduction and internal fixation using a T-shaped iliac crest autograft. Table 1 describes the pearls and pitfalls that should be taken into account when performing this operation, and Table 2 lists the advantages and disadvantages of performing this operation.Table 1 Pearls and Pitfalls

Pearls	Pitfalls	
Careful dissection	When dissecting the pseudarthrosis, the surgeon should take care to protect the underlying plexus.	
Measurement of size of pseudarthrosis site	Leaving too much of a gap between the bone and osteotomy surface can lead to nonunion.	
Use of iliac crest bone graft	The iliac crest has natural osteoinductivity and increased trabecular surface, which make it an ideal bone graft.	

Table 2 Advantages and Disadvantages

Advantages	
 A stable construct is achieved.	
 The T-shaped graft leads to increased stability.	
 The plate yields increased stability.	
Disadvantages	
 The use of a plate and screws could lead to symptomatic hardware.	
 The prominence of the graft could lead to esthetic concerns.	
 There is potential concern for increased infection rates.	

When surgery is performed, the most common methods of fixation involve resection of the pseudarthrosis and placement of an autologous iliac crest bone graft that is secured either via internal plate fixation or with K-wires.10,11 Additionally, age at the time of surgery is controversial, but recent studies have reported higher rates of union in patients treated at an older age than in infants treated with suture fixation.6 Regarding the repair construct, a systematic review revealed a similar healing rate when comparing plate fixation with the use of K-wires.11 Whereas previous studies relied on K-wire fixation, more recent studies have reported increasing use of plating.6,8 The literature lacks consensus on the ideal method of fixation, with varying results reported. Some studies indicate faster union and fewer complications with plating,13 whereas others highlight increased infection rates associated with this method.8

Treatment of pseudarthrosis is complicated by reported nonunion rates of approximately 30%.8,11 The leading cause of nonunion is mechanical factors or a large gap between bone surfaces, with an ideal gap being less than 0.01 mm and interfragmentary strain being less than 2%.14,15 Furthermore, unstable fixation is a risk factor for infection and leads to worse outcomes.16 It has been shown that micromovement in the osteotomy can induce callus proliferation—but only in cases in which there is not a large gap between the bone and osteotomy surface.17,18 Given the importance of stabilization and minimal gap allowance, we opted to use a plate in addition to direct cortical screw fixation of our graft. The decision to use a T-shaped graft was made because it increases the surface area to promote bone healing and provides increased stability in the anterior-posterior as well as medial-lateral dimensions after secure fixation. A top hat–shaped iliac crest graft has previously been described in the hand literature for metacarpal nonunions, which offers similar theories toward the benefit of this technique.19 Autogenous iliac crest bone graft is largely preferred owing to its natural osteoinductivity and increased trabecular surface area, which increases incorporation into the graft site.20,21 Some potential disadvantages of this technique are the risk of symptomatic hardware and potential esthetic concerns owing to the larger shaped bone graft. However, given the high rate of nonunion in CPC, this option seems to provide the benefit of avoiding poor outcomes and further surgical intervention.

Disclosures

The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: P.C. reports a consulting or advisory relationship with DJO Surgical, DePuy Synthes, 10.13039/100009026 Smith & Nephew , and Exactech; owns equity or stocks in TitinKM; and reports board membership with Journal of Shoulder and Elbow Surgery. All other authors (A.D.S., L.R.) declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Supplementary Data

Video 1

Surgical technique using T-shaped iliac crest bone graft for treatment of clavicular pseudarthrosis. The patient is placed in the supine position, and the surgical procedure begins with the harvest of a 3 × 1-cm square from the iliac crest (not shown). After this, attention is turned to the clavicle. After dissection, an oscillating saw is used to excise the pseudarthrosis, creating a 4-mm gap. The ends are drilled, and the anterior surface is burred to spur a healing surface. The iliac crest autograft is then cut into a T shape based on the defect. A 3.5-mm titanium plate (Synthes) is bent to match the bone shape and fixated using a standard compression technique. After plate fixation, the graft is fixated to the bone ends from anterior to posterior using 2.7-mm cortical screws. Thereafter, the wound is closed per surgeon preference.
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