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Selected anteromedial coronoid fractures can be treated nonoperatively
ARTICLE IN PRESS J Shoulder Elbow Surg (2016) ■■, ■■–■■
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ORIGINAL ARTICLE
Selected anteromedial coronoid fractures can be treated nonoperatively Kevin Chan, MD, MSc, FRCSC, Kenneth J. Faber, MD, MHPE, FRCSC, Graham J.W. King, MD, MSc, FRCSC, George S. Athwal, MD, FRCSC* Roth McFarlane Hand and Upper Limb Center, St. Joseph’s Health Care, University of Western Ontario, London, ON, Canada Background: Surgical fixation is currently recommended for unstable anteromedial coronoid fractures, but the role of nonoperative management is not well defined. Our purpose was to report the functional and radiographic outcomes of select patients managed nonoperatively. Methods: Between 2006 and 2012, 10 patients with anteromedial coronoid fractures underwent nonoperative treatment. Outcomes assessed included elbow range of motion (ROM), stability, strength, radiographs, and 3 functional questionnaires, including the Patient-Rated Elbow Evaluation, Disabilities of Arm, Shoulder and Hand, and Mayo Elbow Performance Index. Results: There were 9 anteromedial subtype 2 coronoid fractures and 1 subtype 3. Mean fragment size was 5 mm, with a mean displacement of 3 mm for the subtype 2 fractures. The subtype 3 fracture was 9 mm in size with 1 mm of maximal gap displacement. At a mean follow-up of 50 months (range, 12-83 months), the average ROM of the affected elbow was 137° ± 8° of flexion, 2° ± 5° of extension, 88° ± 5° of pronation, and 86° ± 10° of supination. The mean Patient-Rated Elbow Evaluation score was 9 ± 13, Mayo Elbow Performance Index score was 94 ± 8, and the Disabilities of Arm, Shoulder and Hand score was 7 ± 9. All patients had bony union without radiographic arthrosis. There were no cases of recurrent instability or delayed surgical intervention. Conclusions: Current indications for nonoperative management, based on the results of this study, include fractures that are small, minimally displaced, and most importantly, demonstrate no evidence of elbow subluxation. The elbow joint must be congruent and demonstrate a stable ROM to a minimum of 30° of extension. For selected anteromedial coronoid fractures, nonoperative management is an option that can lead to good clinical and radiographic outcomes. Level of evidence: Level IV; Case Series; Treatment Study © 2016 Journal of Shoulder and Elbow Surgery Board of Trustees. All rights reserved. Keywords: elbow; coronoid; fracture; instability; anteromedial coronoid; varus posteromedial instability
The University of Western Ontario Research Ethics Board approved the study protocol (study number 103067). *Reprint requests: George S. Athwal, MD, FRCSC, 268 Grosvenor St, London, ON N6A 4L6, Canada. E-mail address: [email protected] (G.S. Athwal).
Fractures of the coronoid process have historically been classified according to the fragment size on a lateral radiograph as type 1 (tip), 2 (up to 50% of the coronoid), or 3 (greater than 50%).15 Improved recognition of various injury patterns has increased our understanding of coronoid fractures and has led to a newer classification by O’Driscoll et al.10 This classification considers the anatomic location
1058-2746/$ - see front matter © 2016 Journal of Shoulder and Elbow Surgery Board of Trustees. All rights reserved. http://dx.doi.org/10.1016/j.jse.2016.02.025
ARTICLE IN PRESS 2 and morphology of the fracture, which helps to predict the injury mechanism, associated injuries, and treatment strategy. Anteromedial coronoid fractures are classified as type 2 in this system and are further divided into 3 subtypes: 1 (rim), 2 (rim and tip), or 3 (rim and sublime tubercle). These fractures are theorized to occur with a distinct injury mechanism involving an axial load with a varus posteromedial torque.5,17 As a result, they are commonly associated with an avulsion of the lateral collateral ligament off of the lateral epicondyle and are less likely to have concomitant injuries to the radial head and medial collateral ligament.5,6,17 Operative intervention is typically recommended for anteromedial coronoid fractures, although the evidence stems from expert opinion or small case series.6,17 Nonoperative treatment may be indicated for small, minimally displaced fractures with no elbow subluxation, but the available evidence is limited by short follow-up and small sample sizes.8,18 This study evaluated the results of carefully selected patients with anteromedial coronoid fractures after a purposeful nonsurgical treatment protocol.
Materials and methods Study design Between 2006 and 2012, 10 patients with radiographically documented anteromedial coronoid fractures underwent nonoperative management by 1 of 3 participating surgeons (K.J.F., G.J.W.K., G.S.A.). Patients eligible for participation in the study were contacted by an independent physician (K.C.) who was not directly involved with their care. After informed consent, each patient’s medical record was retrospectively reviewed for demographic information and clinical course. Computed tomography (CT) images were used to classify the anteromedial coronoid fractures according to the system by O’Driscoll et al.10 The anteromedial coronoid rim is classically located between the tip of the coronoid and the sublime tubercle.10 Two-dimensional CT images were also used to measure the maximal fragment size and displacement in the coronal plane by selecting an axial cut of the coronoid (Fig. 1). CT images were obtained with 1.25-mm axial slices.
Description of treatment We used a nonoperative treatment protocol that is similar to a previously published study.4 In the acute setting, patients underwent closed reduction under conscious sedation, if applicable, and were subsequently immobilized in a posterior elbow splint at 90° of flexion with the forearm in neutral rotation. All patients were subsequently assessed by 1 of 3 fellowship-trained elbow surgeons (K.J.F., G.J.K., G.S.A.) within 1 week of injury. Patients underwent a physical examination and a CT scan to characterize the anteromedial coronoid fractures. The criteria applied to identify patients
K. Chan et al.
Figure 1 An axial cut of the coronoid was obtained from 2-dimensional computed tomography images to measure the maximal fragment size and displacement in the coronal plane.
suitable for nonoperative management were (1) a congruent elbow joint seen on plain radiographs and CT scans, (2) a stable arc of active elbow motion to a minimum of 30° of extension with the forearm in neutral rotation to allow early range of motion (ROM) within the first 10 to 14 days, and (3) normal findings with the hyperpronation and gravity varus stress test. Patients who met the prespecified indications for nonoperative treatment were referred to therapy for supervised ROM exercises within a stable arc in the first 10 to 14 days after injury. We are unaware of any validated clinical examination maneuvers for varus posteromedial rotatory instability (PMRI). Typically, we test for dynamic PMRI by palpating for subluxation with hyperpronation of the forearm and the elbow at 90° of flexion (hyperpronation test). In addition, we use a gravity varus stress test (Fig. 2) by placing the shoulder in 90° abduction and then asking the patient to flex and extend the elbow with the forearm in neutral rotation. A positive test is when the patient describes a sense of instability or experiences grinding or crepitation in the elbow. Patients were seen weekly thereafter for 3 weeks for repeated clinical and radiographic examinations to monitor for fracture displacement, subluxation, or dislocation of the elbow. Active and active assisted elbow flexion/extension exercises with the forearm in neutral rotation were initiated within 2 weeks of injury. Overhead exercises with supine positioning were performed to allow early motion with the effect of gravity to maintain a congruous reduction.12 Shoulder abduction was avoided to minimize varus stress on the injured elbows. A resting elbow splint at 90° of flexion was used for comfort in between exercises until fracture and soft tissue healing progressed, usually by approximately 6 weeks after injury. Strengthening exercises were then added. Static progressive extension splints were used as needed to manage residual flexion contractures after 6 weeks.
ARTICLE IN PRESS Nonoperative anteromedial coronoid fractures
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Figure 2 Gravity varus stress test for posteromedial rotatory instability. The patient is asked to place the shoulder in 90° abduction with the forearm in neutral rotation. The test is positive when the patient experiences instability or crepitations while the elbow is actively moved from (A) flexion to (B) extension.
Description of outcome measures
Statistical analyses
Patients returned to the clinic for a study-specific evaluation by an observer (K.C.) not involved with their care. The outcome measures used in this study included 3 functional outcome scores (Patient-Rated Elbow Evaluation [PREE], Mayo Elbow Performance Index [MEPI], and Disabilities of the Arm, Shoulder, and Hand [DASH]), elbow ROM, stability, isometric strength measurements, and radiographic evaluation. Elbow motion was recorded using a standard long-arm goniometer for flexion, extension, pronation, and supination, as reported by Armstrong et al.2 Measurements for forearm rotation were based off of the distal forearm. Medial and lateral instability was evaluated by applying a varus and valgus stress to the elbow. Posterolateral rotatory instability was tested using the posterolateral pivot shift test,9 hypersupination test, and the chair-rise sign. 14 PMRI was evaluated using the hyperpronation and gravity varus stress tests, as described above. Stability was graded as 1 (stable), 2 (moderate instability), or 3 (gross instability). We considered elbows unstable if any one of the above physical examination tests were positive for instability. Isometric strength measurements were performed using the Biodex System 4 Pro (Biodex Medical Systems, Shirley, NY, USA). Testing was done with the patient sitting, the shoulder in neutral flexion/abduction, and the elbow at 90° of flexion and neutral rotation. Three maximal contractions were performed, and the mean value was recorded for elbow flexion, extension, pronation, and supination. Measurements were repeated for the contralateral unaffected elbow for comparison. Radiographic evaluation consisted of standard anteroposterior and lateral radiographs of the affected elbow. Radiographs were examined for evidence of bony union, subluxation, and elbow arthrosis, which was graded according to the system of Broberg and Morrey.3,7 This consisted of grade 0 (normal joint), grade 1 (mild joint space narrowing with minimal osteophytes), grade 2 (moderate joint narrowing and osteophytes), and grade 3 (severe). We also reviewed medical records and interviewed patients for the presence of complications, including instability, stiffness, ulnar neuritis, and need for surgical intervention.
Descriptive statistics were used to report summary data, including means and standard deviations for continuous data. Where applicable, a paired t test was used to measure statistical difference between means. A threshold of P ≤ .05 was used for statistical significance.
Results Patient demographics Ten patients (6 men, 4 women) satisfied our inclusion criteria and were treated between 2006 and 2012. The average age at the time of injury was 49 ± 10 years (range, 28-61 years). Mean follow-up time was 50 ± 24 months (range, 12-83 months). The mechanism of injury was a fall from standing height in 5 patients, a sports-related injury in 4, and a fall from a ladder in 1. There were no open fractures. One patient had a concomitant elbow dislocation requiring a closed reduction.
Fracture characteristics According to the O’Driscoll classification, there were 9 anteromedial coronoid subtype 2 fractures (Fig. 3) and one subtype 3 fracture (Fig. 4). The subtype 2 injuries had an average fragment size of 5 ± 1 mm (range, 2-7 mm) with a mean displacement of 3 ± 2 mm (range, 0-7 mm). The subtype 3 fracture was 9 mm in size with 1 mm of maximal gap, but no articular step. There were no associated radial head fractures in our series.
Functional outcomes scores The mean PREE score was 9 ± 13, MEPI was 94 ± 8, and DASH score was 7 ± 9. According to the MEPI, 6 patients had an excellent outcome, and 4 patients were rated as good.
ARTICLE IN PRESS 4
K. Chan et al.
Figure 3 Example of an anteromedial coronoid subtype 2 fracture treated nonoperatively. Shown here are (A, B) initial plain radiographs, (C) a 3-dimensional computed tomography reconstruction image, and (D) a 2-dimensinal computed tomography axial image.
ROM and strength
Radiographic outcomes and complications
The mean ROM of the affected elbow was 137° ± 8° of flexion (range, 120°-150°), 2° ± 5° of extension (range, 0°-15°), 88° ± 5° of pronation (range, 75-90°), and 86° ± 10° of supination (range, 60-90°). This corresponded with the following percentages of the contralateral, unaffected elbow: 100% (P = .92), 97% (P = .06), 100% (P = .34), and 98% (P = .51), respectively. These results were not statistically different. The mean affected elbow strength was 38 ± 24 Newtonmeters (Nm) of flexion, 34 ± 17 Nm of extension, 7 ± 3 Nm of pronation, and 6 ± 3 Nm of supination. These strength measurements corresponded with the following percentages of the contralateral, unaffected elbow: 82% (P = .17), 83% (P = .13), 92% (P = .69), and 74% (P = .20), respectively. There was no statistical difference in strength between the 2 sides.
All patients demonstrated bony union without radiographic evidence of elbow subluxation/instability or post-traumatic arthrosis. None of the patients experienced clinical instability at the latest follow-up, and there were no incidences of delayed surgical intervention.
Discussion Current literature suggests that operative fixation of anteromedial coronoid fractures may lead to better elbow function, even when the fracture is very small.6,11 Doornberg and Ring6 analyzed 9 patients who were felt to have had limited treatment, including 3 who had nonoperative treatment, 4 who did not have the anteromedial coronoid fracture addressed operatively, and 2 who
ARTICLE IN PRESS Nonoperative anteromedial coronoid fractures
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Figure 4 A 44-year-old man fell while playing soccer. (A-D) He sustained an undisplaced, anteromedial coronoid subtype 3 fracture. (E, F) After 36 months of follow-up, the fracture healed uneventfully, and the patient has no pain and full range of motion.
received tenuous surgical fixation. They found that 7 of these 9 patients had persistent problems with elbow instability, and the remaining 2 patients who did not have instability were believed to be “atypical.”6 As a result, there have been limited studies8,18 that have explored the possible indications and associated outcomes after nonoperative treatment. Although less common, in our experience, we believe that some of these injuries can be successfully managed without surgery. We therefore reviewed the clinical results of a select cohort of patients with anteromedial coronoid fractures who were treated nonsurgically after meeting specific inclusion criteria. At a mean follow-up of 50 months, the 10 patients in our case series had regained nearly symmetric elbow motion with satisfactory strength and function. It was interesting to note that patients lost approximately 25% supination strength, although this did not translate into poor functional outcomes. There were no instances of instability or need for delayed surgical intervention. Our results coincide with 2 case reports documenting successful nonoperative treatment of anteromedial coronoid fractures.8,18 We believe that there are important similarities that may be generalizable to the management of these fractures. Nonoperative treatment can be considered if there is no evidence of static elbow subluxation or dislocation. The detection of subtle dynamic elbow instability is more difficult in the acute setting. However, we used the hyperpronation and gravity varus
stress tests to identify and exclude patients who may have had clinically significant PMRI that warranted operative stabilization. In addition, we defined a clinically stable joint if the elbow could actively extend with the forearm in neutral rotation to a minimum of 30° within the first 10 to 14 days after injury. Finally, our data suggest that small, minimally displaced or undisplaced anteromedial subtype 2 fractures can be amenable to a careful, nonoperative rehabilitation protocol, provided that the elbow remains reduced as previously described. These injuries do not involve the sublime tubercle and sufficient medial ligamentous support may remain intact, thereby permitting early rehabilitation while the coronoid fracture and lateral ligaments heal. Unfortunately, we cannot comment on anteromedial subtype 1 fractures because we did not encounter any of these patients in our series, although a biomechanical study by Pollock et al13 suggested that they may be treated nonoperatively as well if the fracture fragments are small. Thus, we included only those patients with anteromedial coronoid fractures who had a sufficiently stable elbow joint, both statically and dynamically, to permit early rehabilitation. In this study, 1 minimally displaced anteromedial coronoid subtype 3 fracture was treated without surgical fixation (Fig. 4). The patient recovered uneventfully and has been monitored for 3 years since the initial injury. Similarly, Moon et al8 treated 1 patient with the same fracture pattern and achieved good results at 24 months of follow-up.
ARTICLE IN PRESS 6 Although these 2 cases illustrate that subtype 3 fractures can be successfully managed nonoperatively, we caution against extrapolating this treatment strategy to all subtype 3 fracture types, because these fracture patterns lack critical medial and lateral ligamentous restraints and can be unstable.13 Surgical fixation may be necessary to restore stability, and clinical reports of outcomes after fracture fixation have demonstrated good results in a small series.11 On the basis of a limited sample size, we believe that subtype 3 fractures should be treated surgically if there is any fragment displacement or evidence of joint instability. If patients elect for nonoperative management, the treating physician should use advanced imaging to confirm that the fracture is truly undisplaced before embarking on a careful treatment plan that includes rehabilitation and frequent reassessments to ensure the joint remains stable and that the fracture remains well aligned. In another study, Rhyou et al16 applied a treatment algorithm to 18 patients with anteromedial coronoid fractures. Treatment decisions were determined by the fragment size and the results of varus stress testing with the forearm in pronation using fluoroscopy. They identified only 1 patient who was managed conservatively using their approach. In our opinion, the role and accuracy of varus stress testing in the acute setting is still poorly defined for patients with anteromedial coronoid fractures. In our study, varus stress was applied using dynamic fluoroscopy in 4 patients, and none demonstrated varus posteromedial instability. However, limitations of fluoroscopic varus stress testing include pain in the acute setting and variability in the amount of force applied by the orthopedic surgeon. Further studies are warranted to document the accuracy and utility of varus stress tests for complex elbow instability. Despite this, given adequate muscle relaxation and pain relief, we expect that many of our patients would likely have demonstrated varus instability; but, similar to the management of an acute simple dislocation of the elbow, nonoperative treatment can be successful in most patients despite demonstrable instability demonstrated under anesthesia.1 We have also identified a difference between clinical outcomes and in vitro biomechanical results. Pollock et al13 showed that there was persistent varus elbow instability with larger anteromedial coronoid fractures (>5 mm subtype 1, >2.5 mm subtype 2, or subtype 3), even after secure repair of the lateral collateral ligament using an elbow motion simulator in vitro. They concluded that internal fixation should be considered for these larger fractures.13 However, we identified 1 patient with a subtype 3 anteromedial coronoid fracture in our series, and Moon et al8 also had a similar injury in 1 patient in their series. Both patients were successfully managed with purposeful nonoperative treatment. In our series, the average fragment size of the anteromedial coronoid subtype 2 fractures was 5 mm, whereas Pollock et al13 showed persistent instability with fragments >2.5 mm. Despite having mean fragment sizes larger than Pollock et al,13 we encountered no patients who required surgery for instability. In the clinical setting, it is possible that muscle forces stabilize the elbow with activation in vivo, and together with avoiding varus elbow stress, this may be sufficient to
K. Chan et al. allow osteoligamentous healing and to maintain stability over time. Additional studies are also needed to examine the combined effects of varying fragment sizes and displacement on elbow stability. Therefore, definitively concluding on a threshold fragment size from available data is difficult, but minimally displaced (≤3 mm) anteromedial coronoid subtype 2 fractures may be considered for nonoperative treatment as long as the elbow joint is concentrically reduced. Our study had several strengths, including the largest series of patients with anteromedial coronoid fractures managed nonsurgically. Despite this, the overall sample size is comparatively small. Additional investigations with multicenter collaboration would further clarify the optimal indications and treatment for this relatively uncommon fracture pattern. Another strength of our study is that all patients were monitored for a minimum of 12 months, with the longest followup being 83 months. They all returned for a clinical and radiographic review, completion of functional outcome questionnaires, and objective strength testing. Furthermore, we carefully applied clear and strict inclusion criteria to the patients in our series. Weaknesses of the current study include its small sample size and noncomparative and nonrandomized design. Often owing to fracture comminution, our technique for measuring maximal fragment size and displacement on CT images may produce variability, but this was not directly examined. Additional studies are also needed to better define the clinical tests for varus posteromedial elbow instability and to clarify the optimal rehabilitation after these fractures.
Conclusions Nonoperative treatment may be considered for patients with anteromedial coronoid fractures if they meet all of the following criteria: (1) a concentrically reduced elbow joint seen on both plain radiographs and CT images, (2) a stable ROM to a minimum of 30° of extension, and (3) normal findings on hyperpronation and gravity varus stress testing. The fractures in this study that met these criteria were typically subtype 2, and they were small and minimally displaced. As for any nonoperative management, patients should be compliant with their splinting and exercises and be available for serial follow-up to monitor for elbow instability and fracture displacement.
Disclaimer Graham J.W. King received royalties from Wright Medical, which may be related to the subject of this work. The other authors, their immediate families, and any research foundations with which they are affiliated did not receive any financial payments or other benefits from any commercial entity related to the subject of this article.
ARTICLE IN PRESS Nonoperative anteromedial coronoid fractures
References 1. Anakwe RE, Middleton SD, Jenkins PJ, McQueen MM, Court-Brown CM. Patient-reported outcomes after simple dislocation of the elbow. J Bone Joint Surg Am 2011;93:1220-6. http://dx.doi.org/10.2106/ jbjs.j.00860 2. Armstrong AD, MacDermid JC, Chinchalkar S, Stevens RS, King GJ. Reliability of range-of-motion measurement in the elbow and forearm. J Shoulder Elbow Surg 1998;7:573-80. 3. Broberg MA, Morrey BF. Results of treatment of fracture-dislocations of the elbow. Clin Orthop Relat Res 1987;216:109-19. 4. Chan K, MacDermid JC, Faber KJ, King GJ, Athwal GS. Can we treat select terrible triad injuries nonoperatively? Clin Orthop Relat Res 2014;472:2092-9. http://dx.doi.org/10.1007/s11999-014-3518-9 5. Doornberg JN, Ring D. Coronoid fracture patterns. J Hand Surg [Am] 2006;31:45-52. http://dx.doi.org/10.1016/j.jhsa.2005.08.014 6. Doornberg JN, Ring DC. Fracture of the anteromedial facet of the coronoid process. J Bone Joint Surg Am 2006;88:2216-24. http:// dx.doi.org/10.2106/JBJS.E.01127 7. Lindenhovius A, Karanicolas PJ, Bhandari M, Ring D. Radiographic arthrosis after elbow trauma: interobserver reliability. J Hand Surg [Am] 2012;37:755-9. http://dx.doi.org/10.1016/j.jhsa.2011.12.043 8. Moon JG, Bither N, Jeon YJ, Oh SM. Non surgically managed anteromedial coronoid fractures in posteromedial rotatory instability: three cases with 2 years follow-up. Arch Orthop Trauma Surg 2013;133:1665-8. http://dx.doi.org/10.1007/s00402-013-1846-y 9. O’Driscoll SW, Bell DF, Morrey BF. Posterolateral rotatory instability of the elbow. J Bone Joint Surg Am 1991;73:440-6.
7 10. O’Driscoll SW, Jupiter JB, Cohen MS, Ring D, McKee MD. Difficult elbow fractures: pearls and pitfalls. Instr Course Lect 2003;52:113-34. 11. Park SM, Lee JS, Jung JY, Kim JY, Song KS. How should anteromedial coronoid facet fracture be managed? A surgical strategy based on O’Driscoll classification and ligament injury. J Shoulder Elbow Surg 2015;24:74-82. http://dx.doi.org/10.1016/j.jse.2014.07.010 12. Pipicelli JG, Chinchalkar SJ, Grewal R, Athwal GS. Rehabilitation considerations in the management of terrible triad injury to the elbow. Tech Hand Up Extrem Surg 2011;15:198-208. http://dx.doi.org/10.1097/ BTH.0b013e31822911fd 13. Pollock JW, Brownhill J, Ferreira L, McDonald CP, Johnson J, King G. The effect of anteromedial facet fractures of the coronoid and lateral collateral ligament injury on elbow stability and kinematics. J Bone Joint Surg Am 2009;91:1448-58. http://dx.doi.org/10.2106/jbjs.h.00222 14. Regan W, Lapner PC. Prospective evaluation of two diagnostic apprehension signs for posterolateral instability of the elbow. J Shoulder Elbow Surg 2006;15:344-6. http://dx.doi.org/10.1016/j.jse.2005.03.009 15. Regan W, Morrey B. Fractures of the coronoid process of the ulna. J Bone Joint Surg Am 1989;71:1348-54. 16. Rhyou IH, Kim KC, Lee JH, Kim SY. Strategic approach to O’Driscoll type 2 anteromedial coronoid facet fracture. J Shoulder Elbow Surg 2014;23:924-32. http://dx.doi.org/10.1016/j.jse.2014.02.016 17. Sanchez-Sotelo J, O’Driscoll SW, Morrey BF. Medial oblique compression fracture of the coronoid process of the ulna. J Shoulder Elbow Surg 2005;14:60-4. http://dx.doi.org/10.1016/j.jse.2004.04.012 18. Van Der Werf HJ, Guitton TG, Ring D. Non-operatively treated fractures of the anteromedial facet of the coronoid process: a report of six cases. Shoulder Elbow 2010;2:40-2. http://dx.doi.org/10.1111/j.1758-5740 .2009.00044.x
www.elsevier.com/locate/ymse
ORIGINAL ARTICLE
Selected anteromedial coronoid fractures can be treated nonoperatively Kevin Chan, MD, MSc, FRCSC, Kenneth J. Faber, MD, MHPE, FRCSC, Graham J.W. King, MD, MSc, FRCSC, George S. Athwal, MD, FRCSC* Roth McFarlane Hand and Upper Limb Center, St. Joseph’s Health Care, University of Western Ontario, London, ON, Canada Background: Surgical fixation is currently recommended for unstable anteromedial coronoid fractures, but the role of nonoperative management is not well defined. Our purpose was to report the functional and radiographic outcomes of select patients managed nonoperatively. Methods: Between 2006 and 2012, 10 patients with anteromedial coronoid fractures underwent nonoperative treatment. Outcomes assessed included elbow range of motion (ROM), stability, strength, radiographs, and 3 functional questionnaires, including the Patient-Rated Elbow Evaluation, Disabilities of Arm, Shoulder and Hand, and Mayo Elbow Performance Index. Results: There were 9 anteromedial subtype 2 coronoid fractures and 1 subtype 3. Mean fragment size was 5 mm, with a mean displacement of 3 mm for the subtype 2 fractures. The subtype 3 fracture was 9 mm in size with 1 mm of maximal gap displacement. At a mean follow-up of 50 months (range, 12-83 months), the average ROM of the affected elbow was 137° ± 8° of flexion, 2° ± 5° of extension, 88° ± 5° of pronation, and 86° ± 10° of supination. The mean Patient-Rated Elbow Evaluation score was 9 ± 13, Mayo Elbow Performance Index score was 94 ± 8, and the Disabilities of Arm, Shoulder and Hand score was 7 ± 9. All patients had bony union without radiographic arthrosis. There were no cases of recurrent instability or delayed surgical intervention. Conclusions: Current indications for nonoperative management, based on the results of this study, include fractures that are small, minimally displaced, and most importantly, demonstrate no evidence of elbow subluxation. The elbow joint must be congruent and demonstrate a stable ROM to a minimum of 30° of extension. For selected anteromedial coronoid fractures, nonoperative management is an option that can lead to good clinical and radiographic outcomes. Level of evidence: Level IV; Case Series; Treatment Study © 2016 Journal of Shoulder and Elbow Surgery Board of Trustees. All rights reserved. Keywords: elbow; coronoid; fracture; instability; anteromedial coronoid; varus posteromedial instability
The University of Western Ontario Research Ethics Board approved the study protocol (study number 103067). *Reprint requests: George S. Athwal, MD, FRCSC, 268 Grosvenor St, London, ON N6A 4L6, Canada. E-mail address: [email protected] (G.S. Athwal).
Fractures of the coronoid process have historically been classified according to the fragment size on a lateral radiograph as type 1 (tip), 2 (up to 50% of the coronoid), or 3 (greater than 50%).15 Improved recognition of various injury patterns has increased our understanding of coronoid fractures and has led to a newer classification by O’Driscoll et al.10 This classification considers the anatomic location
1058-2746/$ - see front matter © 2016 Journal of Shoulder and Elbow Surgery Board of Trustees. All rights reserved. http://dx.doi.org/10.1016/j.jse.2016.02.025
ARTICLE IN PRESS 2 and morphology of the fracture, which helps to predict the injury mechanism, associated injuries, and treatment strategy. Anteromedial coronoid fractures are classified as type 2 in this system and are further divided into 3 subtypes: 1 (rim), 2 (rim and tip), or 3 (rim and sublime tubercle). These fractures are theorized to occur with a distinct injury mechanism involving an axial load with a varus posteromedial torque.5,17 As a result, they are commonly associated with an avulsion of the lateral collateral ligament off of the lateral epicondyle and are less likely to have concomitant injuries to the radial head and medial collateral ligament.5,6,17 Operative intervention is typically recommended for anteromedial coronoid fractures, although the evidence stems from expert opinion or small case series.6,17 Nonoperative treatment may be indicated for small, minimally displaced fractures with no elbow subluxation, but the available evidence is limited by short follow-up and small sample sizes.8,18 This study evaluated the results of carefully selected patients with anteromedial coronoid fractures after a purposeful nonsurgical treatment protocol.
Materials and methods Study design Between 2006 and 2012, 10 patients with radiographically documented anteromedial coronoid fractures underwent nonoperative management by 1 of 3 participating surgeons (K.J.F., G.J.W.K., G.S.A.). Patients eligible for participation in the study were contacted by an independent physician (K.C.) who was not directly involved with their care. After informed consent, each patient’s medical record was retrospectively reviewed for demographic information and clinical course. Computed tomography (CT) images were used to classify the anteromedial coronoid fractures according to the system by O’Driscoll et al.10 The anteromedial coronoid rim is classically located between the tip of the coronoid and the sublime tubercle.10 Two-dimensional CT images were also used to measure the maximal fragment size and displacement in the coronal plane by selecting an axial cut of the coronoid (Fig. 1). CT images were obtained with 1.25-mm axial slices.
Description of treatment We used a nonoperative treatment protocol that is similar to a previously published study.4 In the acute setting, patients underwent closed reduction under conscious sedation, if applicable, and were subsequently immobilized in a posterior elbow splint at 90° of flexion with the forearm in neutral rotation. All patients were subsequently assessed by 1 of 3 fellowship-trained elbow surgeons (K.J.F., G.J.K., G.S.A.) within 1 week of injury. Patients underwent a physical examination and a CT scan to characterize the anteromedial coronoid fractures. The criteria applied to identify patients
K. Chan et al.
Figure 1 An axial cut of the coronoid was obtained from 2-dimensional computed tomography images to measure the maximal fragment size and displacement in the coronal plane.
suitable for nonoperative management were (1) a congruent elbow joint seen on plain radiographs and CT scans, (2) a stable arc of active elbow motion to a minimum of 30° of extension with the forearm in neutral rotation to allow early range of motion (ROM) within the first 10 to 14 days, and (3) normal findings with the hyperpronation and gravity varus stress test. Patients who met the prespecified indications for nonoperative treatment were referred to therapy for supervised ROM exercises within a stable arc in the first 10 to 14 days after injury. We are unaware of any validated clinical examination maneuvers for varus posteromedial rotatory instability (PMRI). Typically, we test for dynamic PMRI by palpating for subluxation with hyperpronation of the forearm and the elbow at 90° of flexion (hyperpronation test). In addition, we use a gravity varus stress test (Fig. 2) by placing the shoulder in 90° abduction and then asking the patient to flex and extend the elbow with the forearm in neutral rotation. A positive test is when the patient describes a sense of instability or experiences grinding or crepitation in the elbow. Patients were seen weekly thereafter for 3 weeks for repeated clinical and radiographic examinations to monitor for fracture displacement, subluxation, or dislocation of the elbow. Active and active assisted elbow flexion/extension exercises with the forearm in neutral rotation were initiated within 2 weeks of injury. Overhead exercises with supine positioning were performed to allow early motion with the effect of gravity to maintain a congruous reduction.12 Shoulder abduction was avoided to minimize varus stress on the injured elbows. A resting elbow splint at 90° of flexion was used for comfort in between exercises until fracture and soft tissue healing progressed, usually by approximately 6 weeks after injury. Strengthening exercises were then added. Static progressive extension splints were used as needed to manage residual flexion contractures after 6 weeks.
ARTICLE IN PRESS Nonoperative anteromedial coronoid fractures
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Figure 2 Gravity varus stress test for posteromedial rotatory instability. The patient is asked to place the shoulder in 90° abduction with the forearm in neutral rotation. The test is positive when the patient experiences instability or crepitations while the elbow is actively moved from (A) flexion to (B) extension.
Description of outcome measures
Statistical analyses
Patients returned to the clinic for a study-specific evaluation by an observer (K.C.) not involved with their care. The outcome measures used in this study included 3 functional outcome scores (Patient-Rated Elbow Evaluation [PREE], Mayo Elbow Performance Index [MEPI], and Disabilities of the Arm, Shoulder, and Hand [DASH]), elbow ROM, stability, isometric strength measurements, and radiographic evaluation. Elbow motion was recorded using a standard long-arm goniometer for flexion, extension, pronation, and supination, as reported by Armstrong et al.2 Measurements for forearm rotation were based off of the distal forearm. Medial and lateral instability was evaluated by applying a varus and valgus stress to the elbow. Posterolateral rotatory instability was tested using the posterolateral pivot shift test,9 hypersupination test, and the chair-rise sign. 14 PMRI was evaluated using the hyperpronation and gravity varus stress tests, as described above. Stability was graded as 1 (stable), 2 (moderate instability), or 3 (gross instability). We considered elbows unstable if any one of the above physical examination tests were positive for instability. Isometric strength measurements were performed using the Biodex System 4 Pro (Biodex Medical Systems, Shirley, NY, USA). Testing was done with the patient sitting, the shoulder in neutral flexion/abduction, and the elbow at 90° of flexion and neutral rotation. Three maximal contractions were performed, and the mean value was recorded for elbow flexion, extension, pronation, and supination. Measurements were repeated for the contralateral unaffected elbow for comparison. Radiographic evaluation consisted of standard anteroposterior and lateral radiographs of the affected elbow. Radiographs were examined for evidence of bony union, subluxation, and elbow arthrosis, which was graded according to the system of Broberg and Morrey.3,7 This consisted of grade 0 (normal joint), grade 1 (mild joint space narrowing with minimal osteophytes), grade 2 (moderate joint narrowing and osteophytes), and grade 3 (severe). We also reviewed medical records and interviewed patients for the presence of complications, including instability, stiffness, ulnar neuritis, and need for surgical intervention.
Descriptive statistics were used to report summary data, including means and standard deviations for continuous data. Where applicable, a paired t test was used to measure statistical difference between means. A threshold of P ≤ .05 was used for statistical significance.
Results Patient demographics Ten patients (6 men, 4 women) satisfied our inclusion criteria and were treated between 2006 and 2012. The average age at the time of injury was 49 ± 10 years (range, 28-61 years). Mean follow-up time was 50 ± 24 months (range, 12-83 months). The mechanism of injury was a fall from standing height in 5 patients, a sports-related injury in 4, and a fall from a ladder in 1. There were no open fractures. One patient had a concomitant elbow dislocation requiring a closed reduction.
Fracture characteristics According to the O’Driscoll classification, there were 9 anteromedial coronoid subtype 2 fractures (Fig. 3) and one subtype 3 fracture (Fig. 4). The subtype 2 injuries had an average fragment size of 5 ± 1 mm (range, 2-7 mm) with a mean displacement of 3 ± 2 mm (range, 0-7 mm). The subtype 3 fracture was 9 mm in size with 1 mm of maximal gap, but no articular step. There were no associated radial head fractures in our series.
Functional outcomes scores The mean PREE score was 9 ± 13, MEPI was 94 ± 8, and DASH score was 7 ± 9. According to the MEPI, 6 patients had an excellent outcome, and 4 patients were rated as good.
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K. Chan et al.
Figure 3 Example of an anteromedial coronoid subtype 2 fracture treated nonoperatively. Shown here are (A, B) initial plain radiographs, (C) a 3-dimensional computed tomography reconstruction image, and (D) a 2-dimensinal computed tomography axial image.
ROM and strength
Radiographic outcomes and complications
The mean ROM of the affected elbow was 137° ± 8° of flexion (range, 120°-150°), 2° ± 5° of extension (range, 0°-15°), 88° ± 5° of pronation (range, 75-90°), and 86° ± 10° of supination (range, 60-90°). This corresponded with the following percentages of the contralateral, unaffected elbow: 100% (P = .92), 97% (P = .06), 100% (P = .34), and 98% (P = .51), respectively. These results were not statistically different. The mean affected elbow strength was 38 ± 24 Newtonmeters (Nm) of flexion, 34 ± 17 Nm of extension, 7 ± 3 Nm of pronation, and 6 ± 3 Nm of supination. These strength measurements corresponded with the following percentages of the contralateral, unaffected elbow: 82% (P = .17), 83% (P = .13), 92% (P = .69), and 74% (P = .20), respectively. There was no statistical difference in strength between the 2 sides.
All patients demonstrated bony union without radiographic evidence of elbow subluxation/instability or post-traumatic arthrosis. None of the patients experienced clinical instability at the latest follow-up, and there were no incidences of delayed surgical intervention.
Discussion Current literature suggests that operative fixation of anteromedial coronoid fractures may lead to better elbow function, even when the fracture is very small.6,11 Doornberg and Ring6 analyzed 9 patients who were felt to have had limited treatment, including 3 who had nonoperative treatment, 4 who did not have the anteromedial coronoid fracture addressed operatively, and 2 who
ARTICLE IN PRESS Nonoperative anteromedial coronoid fractures
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Figure 4 A 44-year-old man fell while playing soccer. (A-D) He sustained an undisplaced, anteromedial coronoid subtype 3 fracture. (E, F) After 36 months of follow-up, the fracture healed uneventfully, and the patient has no pain and full range of motion.
received tenuous surgical fixation. They found that 7 of these 9 patients had persistent problems with elbow instability, and the remaining 2 patients who did not have instability were believed to be “atypical.”6 As a result, there have been limited studies8,18 that have explored the possible indications and associated outcomes after nonoperative treatment. Although less common, in our experience, we believe that some of these injuries can be successfully managed without surgery. We therefore reviewed the clinical results of a select cohort of patients with anteromedial coronoid fractures who were treated nonsurgically after meeting specific inclusion criteria. At a mean follow-up of 50 months, the 10 patients in our case series had regained nearly symmetric elbow motion with satisfactory strength and function. It was interesting to note that patients lost approximately 25% supination strength, although this did not translate into poor functional outcomes. There were no instances of instability or need for delayed surgical intervention. Our results coincide with 2 case reports documenting successful nonoperative treatment of anteromedial coronoid fractures.8,18 We believe that there are important similarities that may be generalizable to the management of these fractures. Nonoperative treatment can be considered if there is no evidence of static elbow subluxation or dislocation. The detection of subtle dynamic elbow instability is more difficult in the acute setting. However, we used the hyperpronation and gravity varus
stress tests to identify and exclude patients who may have had clinically significant PMRI that warranted operative stabilization. In addition, we defined a clinically stable joint if the elbow could actively extend with the forearm in neutral rotation to a minimum of 30° within the first 10 to 14 days after injury. Finally, our data suggest that small, minimally displaced or undisplaced anteromedial subtype 2 fractures can be amenable to a careful, nonoperative rehabilitation protocol, provided that the elbow remains reduced as previously described. These injuries do not involve the sublime tubercle and sufficient medial ligamentous support may remain intact, thereby permitting early rehabilitation while the coronoid fracture and lateral ligaments heal. Unfortunately, we cannot comment on anteromedial subtype 1 fractures because we did not encounter any of these patients in our series, although a biomechanical study by Pollock et al13 suggested that they may be treated nonoperatively as well if the fracture fragments are small. Thus, we included only those patients with anteromedial coronoid fractures who had a sufficiently stable elbow joint, both statically and dynamically, to permit early rehabilitation. In this study, 1 minimally displaced anteromedial coronoid subtype 3 fracture was treated without surgical fixation (Fig. 4). The patient recovered uneventfully and has been monitored for 3 years since the initial injury. Similarly, Moon et al8 treated 1 patient with the same fracture pattern and achieved good results at 24 months of follow-up.
ARTICLE IN PRESS 6 Although these 2 cases illustrate that subtype 3 fractures can be successfully managed nonoperatively, we caution against extrapolating this treatment strategy to all subtype 3 fracture types, because these fracture patterns lack critical medial and lateral ligamentous restraints and can be unstable.13 Surgical fixation may be necessary to restore stability, and clinical reports of outcomes after fracture fixation have demonstrated good results in a small series.11 On the basis of a limited sample size, we believe that subtype 3 fractures should be treated surgically if there is any fragment displacement or evidence of joint instability. If patients elect for nonoperative management, the treating physician should use advanced imaging to confirm that the fracture is truly undisplaced before embarking on a careful treatment plan that includes rehabilitation and frequent reassessments to ensure the joint remains stable and that the fracture remains well aligned. In another study, Rhyou et al16 applied a treatment algorithm to 18 patients with anteromedial coronoid fractures. Treatment decisions were determined by the fragment size and the results of varus stress testing with the forearm in pronation using fluoroscopy. They identified only 1 patient who was managed conservatively using their approach. In our opinion, the role and accuracy of varus stress testing in the acute setting is still poorly defined for patients with anteromedial coronoid fractures. In our study, varus stress was applied using dynamic fluoroscopy in 4 patients, and none demonstrated varus posteromedial instability. However, limitations of fluoroscopic varus stress testing include pain in the acute setting and variability in the amount of force applied by the orthopedic surgeon. Further studies are warranted to document the accuracy and utility of varus stress tests for complex elbow instability. Despite this, given adequate muscle relaxation and pain relief, we expect that many of our patients would likely have demonstrated varus instability; but, similar to the management of an acute simple dislocation of the elbow, nonoperative treatment can be successful in most patients despite demonstrable instability demonstrated under anesthesia.1 We have also identified a difference between clinical outcomes and in vitro biomechanical results. Pollock et al13 showed that there was persistent varus elbow instability with larger anteromedial coronoid fractures (>5 mm subtype 1, >2.5 mm subtype 2, or subtype 3), even after secure repair of the lateral collateral ligament using an elbow motion simulator in vitro. They concluded that internal fixation should be considered for these larger fractures.13 However, we identified 1 patient with a subtype 3 anteromedial coronoid fracture in our series, and Moon et al8 also had a similar injury in 1 patient in their series. Both patients were successfully managed with purposeful nonoperative treatment. In our series, the average fragment size of the anteromedial coronoid subtype 2 fractures was 5 mm, whereas Pollock et al13 showed persistent instability with fragments >2.5 mm. Despite having mean fragment sizes larger than Pollock et al,13 we encountered no patients who required surgery for instability. In the clinical setting, it is possible that muscle forces stabilize the elbow with activation in vivo, and together with avoiding varus elbow stress, this may be sufficient to
K. Chan et al. allow osteoligamentous healing and to maintain stability over time. Additional studies are also needed to examine the combined effects of varying fragment sizes and displacement on elbow stability. Therefore, definitively concluding on a threshold fragment size from available data is difficult, but minimally displaced (≤3 mm) anteromedial coronoid subtype 2 fractures may be considered for nonoperative treatment as long as the elbow joint is concentrically reduced. Our study had several strengths, including the largest series of patients with anteromedial coronoid fractures managed nonsurgically. Despite this, the overall sample size is comparatively small. Additional investigations with multicenter collaboration would further clarify the optimal indications and treatment for this relatively uncommon fracture pattern. Another strength of our study is that all patients were monitored for a minimum of 12 months, with the longest followup being 83 months. They all returned for a clinical and radiographic review, completion of functional outcome questionnaires, and objective strength testing. Furthermore, we carefully applied clear and strict inclusion criteria to the patients in our series. Weaknesses of the current study include its small sample size and noncomparative and nonrandomized design. Often owing to fracture comminution, our technique for measuring maximal fragment size and displacement on CT images may produce variability, but this was not directly examined. Additional studies are also needed to better define the clinical tests for varus posteromedial elbow instability and to clarify the optimal rehabilitation after these fractures.
Conclusions Nonoperative treatment may be considered for patients with anteromedial coronoid fractures if they meet all of the following criteria: (1) a concentrically reduced elbow joint seen on both plain radiographs and CT images, (2) a stable ROM to a minimum of 30° of extension, and (3) normal findings on hyperpronation and gravity varus stress testing. The fractures in this study that met these criteria were typically subtype 2, and they were small and minimally displaced. As for any nonoperative management, patients should be compliant with their splinting and exercises and be available for serial follow-up to monitor for elbow instability and fracture displacement.
Disclaimer Graham J.W. King received royalties from Wright Medical, which may be related to the subject of this work. The other authors, their immediate families, and any research foundations with which they are affiliated did not receive any financial payments or other benefits from any commercial entity related to the subject of this article.
ARTICLE IN PRESS Nonoperative anteromedial coronoid fractures
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