TECHNIQUE

A Novel Approach for Coronoid Fractures Dave R. Shukla, MD, Steven M. Koehler, MD, Sara M. Guerra, MD, and Michael R. Hausman, MD

Abstract: The coronoid process serves as an important constraint that provides ulnohumeral joint stability. We describe a novel approach to coronoid fractures that minimizes surgical dissection, without compromising fracture visualization. We present the case of a 65-year-old woman who sustained an anteromedial facet fracture of the coronoid process. The elbow demonstrated intractable posteromedial instability and the inability to maintain reduction even up to 90 degrees. This report describes a surgical approach to the coronoid process that minimizes extensive soft tissue dissection. It is a variation of the previously described approach by Taylor and Scham, although it can achieve a similar exposure without elevation of the entirety of the flexor-pronator mass. Our approach involves a limited skin incision, followed by elevation of enough of the flexor-pronator mass such that adequate visualization of the posterior medial collateral ligament (which was repaired), anteromedial facet, and the fractured fragment of coronoid were achieved. Moreover, this approach enables the course of the ulnar nerve to remain unaltered. Key Words: coronoid fracture, coronoid fixation, elbow injury, posteromedial rotatory instability (Tech Hand Surg 2014;18: 189–193)

T

he coronoid process serves as an important constraint that provides ulnohumeral joint stability. Studies have demonstrated that the coronoid functions as a stabilizer against axial, varus, posteromedial, and posterolateral forces.1,2 Coronoid fractures can occur following a simple dislocation or in conjunction with associated ligamentous injuries and other fractures such as in a complex fracture dislocation. Coronoid process fractures were classified by Reagan and Morrey in 1989 based on lateral view radiographs,3 and again by O’Driscoll et al4 based on fracture patterns as seen on computed tomography (CT) imaging. Multiple surgical approaches have been described for coronoid repair. The senior author (M.R.H.) has been using a less invasive surgical approach that is a variation of a previously described report by Taylor and Scham,5 although the report remains unpublished to our knowledge. It is reasonable to assume that minimizing surgical dissection wherever possible, without compromising fracture visualization, might decrease the risk of additional HO formation as well as joint stiffness, to which the elbow is prone to following fracture dislocation.6

From the Department of Orthopedic Surgery, Mount Sinai Hospital, Mount Sinai Health System, New York, NY. Conflicts of Interest and Source of Funding: The authors report no conflicts of interest and no source of funding. Address correspondence and reprint requests to Michael R. Hausman, MD, Leni and Peter W. May Department of Orthopedic Surgery, Mount Sinai Medical Center, 5 East 98th Street, 9th Floor, Box 1188, New York 10029, NY. E-mail: [email protected]. Supplemental Digital Content is available for this article. Direct URL citations appear in the printed text and are provided in the HTML and PDF versions of this article on the journal’s Website, www. techhandsurg.com. Copyright r 2014 by Lippincott Williams & Wilkins

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ANATOMY The coronoid process of the proximal ulna articulates with the trochlea of the humerus proximally and with the radial head on its lateral side. It forms the greater sigmoid notch in conjunction with the olecranon. As the proximal ulna increases in coronal plane diameter progressing distally, it widens to form the coronoid and the sublime tubercle, onto which the anterior band of the medial collateral ligament (MCL) inserts.

INDICATIONS/CONTRAINDICATIONS Traditionally, isolated coronoid fractures were managed nonoperatively, whereas fractures occurring in “terrible-triad” elbow fracture dislocations were addressed operatively to prevent recurrent instability. However, it has become apparent that coronoid fractures that appear to be isolated may be more sinister, potentially involving injury to the lateral collateral ligament, which could result in “posteromedial rotatory instability”4 (PMRI). Fracture of the anteromedial facet can result in recurrent subluxation, which we consider an indication for operative intervention. We have observed that often the posterior bundle of the MCL is injured as well, and should be repaired. In addition to terrible triad injuries and coronoid fractures resulting in PMRI, Monteggia fractures involving the olecranon can have large coronoid fragments and should undergo operative fixation as well.

CASE REPORT AND SURGICAL TECHNIQUE We present the case of a 65-year-old woman who sustained an injury to her left elbow after a fall. X-ray imaging demonstrated an anteromedial facet fracture of the coronoid process (Figs. 1A, B), which was confirmed using CT (Figs. 1C, D). There was no fracture of the radial head or neck. The elbow demonstrated intractable posteromedial instability, and the inability to maintain reduction even up to 90 degrees, and consequently operative management was pursued. The procedure was performed 7 days after the initial injury. Regional anesthesia was administered, followed by an examination, which confirmed posteromedial instability without posterolateral instability. The arm was secured in a McConnell shoulder positioner in 90 degrees of flexion over the patient’s body (Fig. 2). The proximal extent of the skin incision was 2 cm proximal to the olecranon tip, extending 4 cm distally along the subcutaneous border of the ulna (Fig. 3). Careful blunt subcutaneous dissection was performed to identify the ulnar nerve proximally. The ulnar nerve was unroofed but otherwise left unaltered in its native position. The subcutaneous border of the ulna was then identified and the flexor pronator mass was elevated from the ulna in a posterior to anterior direction (Fig. 4). This allowed for identification of the ruptured posterior MCL and the medial border of the trochlea (Fig. 5). Further dissection anteriorly exposed the anteromedial facet of the coronoid and just anterior to this, the fractured coronoid fragment could be identified. At this point marked posteromedial instability was evident, as gapping

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FIGURE 1. (A) Lateral x-ray view of left elbow demonstrating a coronoid fracture. (B) Anteroposterior view of left elbow demonstrating a coronoid fracture. (C and D) Sagittal computed tomography demonstrating a coronoid fracture.

FIGURE 2. Preoperative patient positioning. Patient is supine with a McConnell arm positioner.

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occurred with the application of a varus stress (Fig. 6). The small piece of the articular surface was identified, carefully and anatomically reduced, and temporarily fixed with a K wire. The position was checked both with visual inspection and the image intensifier, confirming achievement of an anatomic reduction. Next the Acumed (Hillsboro, OR) coronoid plate was fitted against the coronoid fragment and fixed with the center screw. The plate was then rotated into position to compress the fragment in an anatomic reduction. The distal screw was then placed in an oblique manner to fix the fragment under compression. Once this was carried out, the elbow was examined, and a posteromedial stress test was performed once again, demonstrating that significant stability had been restored. Drill holes were then made at the anatomic site of insertion of the posterior bundle of the MCL, and PDS sutures were used to anatomically repair the posterior MCL to the border of the olecranon (Fig. 7). A stress test was then performed under image intensification, confirming that the instability pattern could not be reproduced. The wound was then thoroughly irrigated and the flexor pronator mass was anatomically reattached to the subcutaneous border of the ulna, leaving the ulnar nerve in its anatomically normal position. Final radiographs (Figs. 8, 9) confirmed an anatomic reduction. The temporary fixation wire was trimmed and left in position to provide additional support (Video, Supplemental Digital Content 1, http://links.lww.com/BTH/A47). r

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Novel Approach for Coronoid Fractures

FIGURE 4. Illustration demonstrating the plane of dissection; the flexor carpi ulnaris (FCU) is subperiosteally elevated off of the ulna. The ulnar nerve is visualized and unroofed but otherwise undisturbed. Printed with permission from r Mount Sinai Health System.

Expected Outcomes Fixation of the coronoid and repair or reconstruction of associated ligamentous injuries should restore the ability to resist ulnohumeral subluxation, particularly under rotational stress. Radial head injury or deficiency significantly increases the importance of an intact coronoid in this respect. Extensive soft tissue dissection may have detrimental consequences, particularly about the elbow. Heterotopic bone formation is a common complication following elbow injuries,

FIGURE 3. Illustration demonstrating the posterior skin incision, which extends from 2 cm proximal to the olecranon tip and extends 4 cm distally along the subcutaneous border of the ulna. Printed with permission from r Mount Sinai Health System.

DISCUSSION This report describes a surgical approach to the coronoid process that minimizes extensive soft tissue dissection. It is a variation of the previously described approach by Taylor and Scham,5 although it can achieve a similar exposure without elevation of the entirety of the flexor-pronator mass. We feel such muscular dissection is excessive for achieving fixation of many coronoid fractures. r

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FIGURE 5. Illustration demonstrating retraction of the flexorpronator mass, allowing for visualization of the fractured coronoid process and collateral ligament complex (the posterior bundle of the MCL was ruptured in our case). A-MCL indicates anterior bundle of the medial collateral ligament; P-MCL, posterior bundle of the medial collateral ligament. Printed with permission from r Mount Sinai Health System. www.techhandsurg.com |

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FIGURE 8. Image-intensifier film demonstrating fragment reduction and fixation.

FIGURE 6. (A) Intraoperative PMRI seen with varus stress. (B) PMRI reduced. PMRI indicates posteromedial rotatory instability.

and significant additional dissection may increase the risk of its development.6 In addition, manipulation and the risk of an inadvertent traction injury of the ulnar nerve can be avoided. Doornberg and Ring7 reported postoperative ulnar motor and sensory neuropathies in 2/18 (11%) patients with anteromedial facet fractures. Although 3 different approaches were used, the ulnar nerve was mobilized and transposed anteriorly in all. The authors attributed the neuropathies to handling of or traction on the nerve. In our reported case, the ulnar nerve was unroofed but otherwise left in its native position. Once identified and exposed, it is critical to remain cognizant of the nerve’s location at all times, particularly while using instruments for provisional fixation, placing retractors, and securing hardware. However, the approach can be extended distally along the subcutaneous border of the ulna should the surgeon elect to perform a transposition of the nerve. Several medial approaches to the coronoid have been described (Table 1). As mentioned above, the approached described by Taylor and Scham5 involves an incision along the subcutaneous border of the ulna, followed by subperiosteal dissection medially and elevation of the ulnar and deep heads of the flexor digitorum superficialis and pronator teres,

respectively. The muscular origin of the flexor digitorum profundus is then elevated, with dissection carried anteriorly until the anterior margin of the coronoid and sublime tubercle are delineated. The Hotchkiss approach8 involves a posteromedial skin incision, identification and dissection of the ulnar nerve distally, visualization of the medial antebrachial cutaneous nerve, and splitting of the flexor carpi ulnaris. Morrey and O’Driscoll9 described a posterior elbow incision, which allows for subsequent lateral exposure through a single incision, followed by exposure of the ulnar nerve, elevation of the brachialis and pronator, while leaving a cuff of FCU for closure. Garofalo et al10 described a minimally invasive surgical technique for coronoid fractures, which requires anterior and posterior skin incisions, followed by cannulated screw placement. The presently described approach differs from all of the previous reports, except for that of Taylor and Scham, in that a different muscular interval is utilized. This approach differs from Taylor and Scham’s description in the extent of dissection required to obtain an adequate reduction. Our approach involves a limited skin incision, followed by elevation of enough of the flexor-pronator mass such that adequate visualization of the posterior MCL (which was repaired), anteromedial facet, and the fractured fragment of coronoid were achieved. This approach may be of utility in situations of complex fracture dislocations as well. The pattern of coronoid fracture in terrible-triad injuries is typically a tip fracture (O’Driscoll type I),4 which is possible to address from a lateral approach, along with the radial head fracture and LCL complex disruption.11–13 The approach can also be extended to access the tip of the coronoid by further reflecting the flexor-pronator mass, which would provide access to the entire coronoid. An isolated anterolateral fragment might be more effectively accessed from a lateral approach. However, this approach may be used in cases in which MCL repair or fixation of a more extensive coronoid fracture (ie, anteromedial facet) is required.

Complications

FIGURE 7. Medial collateral ligament (MCL) repair after coronoid plate fixation completed.

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Complications can occur as a result of the initial injury, as well as secondary to iatrogenic insult. Heterotopic ossification is a known complication that follows elbow fracture dislocations. Ulnar nerve injury can occur as a result of the operative approach or in a delayed manner. Although rare, failure of r

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Novel Approach for Coronoid Fractures

FIGURE 9. Postoperative radiographs demonstrating coronoid fracture reduction and elbow stability in supination, pronation, and flexion.

fixation or nonunion can occur as well. Posteromedial rotatory instability may persist and would necessitate additional treatment, possibly with a hinged external fixator. Wound healing complications and arthrofibrosis are significant concerns as well. The optimal type of fixation used to achieve satisfactory alignment of the coronoid is beyond the scope of this report. Our purpose was to propose a less invasive manner by which the coronoid process can be approached. It requires minimal

TABLE 1. Four Possible Approaches for Fixation of Coronoid Fractures

Approach

Incision

FCU-split

Posterior or medial

Interval/Encountered Structures

Floor of cubital tunnel Ulnar nerve transposition or retraction FCU (2 heads) split Anterior band of MCL Taylor and Subcutaneous Elevation of FDS, PT Scham border of ulna Elevation of muscular origin of FDP Dissection distally to anterior coronoid and sublime tubercle Hotchkiss Posteromedial Ulnar nerve exposure skin incision MABC nerve protection Incision of brachial fascia Flexor-pronator mass split Elevation of brachialis, FCR, PT off anterior capsule Morrey and Posterior skin Ulnar nerve exposure O’Driscoll incision Elevation of brachialis and pronator Keep cuff of FCU for closure FCR indicates flexor carpi radialis; FCU, flexor carpi ulnaris; FDP, flexor digitorum profundus; FDS, flexor digitorum superficialis; MABC, medial antebrachial cutaneous nerve; PT, pronator teres.

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soft tissue dissection and allows the ulnar nerve to remain relatively unaltered from its anatomic position. REFERENCES 1. Beingessner DM, Dunning CE, Stacpoole RA, et al. The effect of coronoid fractures on elbow kinematics and stability. Clin Biomechan. 2007;22:183–190. 2. Schneeberger AG, Sadowski MM, Jacob HA. Coronoid process and radial head as posterolateral rotatory stabilizers of the elbow. J Bone Joint Surg Am. 2004;86-A:975–982. 3. Regan W, Morrey B. Fractures of the coronoid process of the ulna. J Bone Joint Surg. 1989;71-A:1348–1354. 4. O’Driscoll SW, Jupiter JB, Cohen MS, et al. Difficult elbow fractures: pearls and pitfalls. Instr Course Lect. 2003;52:113–134. 5. Taylor TK, Scham SM. A posteromedial approach to the proximal end of the ulna for the internal fixation of olecranon fractures. J Trauma. 1969;9:594–602. 6. Ring D, Jupiter JB. Surgical Exposure of Coronoid Fractures. Techn Shoulder Elbow Surg. 2002;3:48–56. 7. Doornberg JN, Ring DC. Fracture of the anteromedial facet of the coronoid process. J Bone Joint Surg Am. 2006;88:2216–2224. 8. Kasparyan NG, Hotchkiss RN. Dynamic skeletal fixation in the upper extremity. Hand Clin. 1997;13:643–663. 9. Morrey B, O’Driscoll S. Fractures of the coronoid and complex instability of the elbow. In: Morrey B, ed. Master Techniques in Orthopedic Surgery: The Elbow. Philadelphia: Lippincott Williams & Wilkins; 2001:129–130. 10. Garofalo R, Bollmann C, Kombot C, et al. Minimal invasive surgery for coronoid fracture: technical note. Knee Surg Sports Traumatol Arthrosc. 2005;13:608–611. 11. Garrigues GE, Wray WH, Lindenhovius ALC, et al. Fixation of the coronoid process in elbow fracture-dislocations. J Bone Joint Surg Am. 2011;93:1873–1881. 12. Dyer G, Ring D. My approach to the terrible triad injury. Oper Tech Orthop. 2010;20:11–16. 13. McKee MD, Pugh DMW, Wild LM, et al. Standard surgical protocol to treat elbow dislocations with radial head and coronoid fractures. Surgical technique. J Bone Joint Surg Am. 2005;87(Suppl 1(Pt 1)): 22–32.

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A novel approach for coronoid fractures.

The coronoid process serves as an important constraint that provides ulnohumeral joint stability. We describe a novel approach to coronoid fractures t...
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