n trauma update Section Editors: David J. Hak, MD, MBA & Philip F. Stahel, MD
Current Treatment Concepts for “Terrible Triad” Injuries of the Elbow Kevin Bohn, MS; Kyros Ipaktchi, MD; Meryl Livermore, MD; Jue Cao, MD; Rodrigo Banegas, MD
Abstract: Elbow fracture-dislocations destabilize the elbow, preventing functional rehabilitation. If left untreated, they commonly result in functional compromise and poor outcomes. The “terrible triad” injury is classically described as a combination of a coronoid process and radial head fractures, as well as a posterolateral elbow dislocation. Surgical treatment to restore stable elbow range of motion has evolved in the past few decades based on increased understanding of elbow biomechanics and the anatomy of these injuries. This article highlights current concepts in the treatment of these complicated injuries. [Orthopedics. 2014; 37(12):831-837.]
otchkiss1 first used the term “terrible triad,” meaning fractures to the coronoid process and radial head with a resulting posterolateral elbow dislocation and refractory instability. The usual traumatic mechanism leading to this injury is a fall on to the outstretched, supinated arm with a valgus stress through the elbow (Figure 1). This
Figure 1: Preoperative anteroposterior (A) and lateral (B) radiographs of a 35-year-old man who sustained a left “terrible triad injury.”
condition accounted for 4% of adult radial head fractures and 31% of elbow dislocations in a study by van Riet and Morrey.2 Terrible triad injuries are seen more commonly in men and have a peak occurrence in the fourth decade of life.3-12 Concurrent ipsilateral injuries to the distal radius, diaphyseal ulna, rotator cuff, and carpal bones have been described.3-12
The authors are from the University of Colorado School of Medicine (KB), Aurora; the Department of Orthopaedic Surgery (KI, ML, RB), Denver Health Medical Center, Denver; and the Department of Orthopaedic Surgery (JC), University of Colorado, Aurora, Colorado. The authors have no relevant financial relationships to disclose. Correspondence should be addressed to: Kyros Ipaktchi, MD, Department of Orthopaedic Surgery, Denver Health Medical Center, 777 Bannock, Denver, CO 80204 ([email protected]
). doi: 10.3928/01477447-20141124-06
The goal of treatment for terrible triad injuries is restoring the bony anatomy and reconstructing the ligamentous restraints of the elbow to provide enough stability for early elbow range of motion and prevent elbow stiffness.3,10,12-15 The elbow is prone to stiffness, even with short-term immobilization. Seijas et al10 reported that most patients treated for terrible triad injuries regained their maximum range of motion during the first 3 to 4 months after treatment. Although outcomes have improved with increased
understanding of elbow biomechanics and advancements in surgical techniques and implants, no clear consensus exists regarding how and in which order to address bony and ligamentous injuries. Several algorithms have been proposed, with most favoring, at a minimum, repair of the radial head, the coronoid process, and the lateral ulnar collateral ligament.5,11,13,15 In addition, due to multiple factors, definitive treatment can sometimes be delayed for these injuries and differences in outcome for acute vs subacute management
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have been recognized.8 Treatment algorithms must be case and patient specific.
Anatomy of the Elbow The elbow joint consists of 3 distinct articulations: the proximal radioulnar, the ulnohumeral, and the radiocapitellar joint. All 3 components are essential for proper range of motion of the forearm and elbow. The elbow has 2 degrees of motion: flexion-extension at the ulnotrochlear joint and supination-pronation at the radiocapitellar joint and the proximal and distal radioulnar joints. Normal range of motion is approximately 0° to 140° in extension and flexion, 85° in supination, and 80° in pronation.16 However, normal daily activity is associated with only 30° of extension, 130° of flexion, 50° of supination, and 50° of pronation.17 The elbow’s stability depends on static and dynamic stabilizers. Static stability is maintained by osseous and capsuloligamentous restraints, whereas muscles crossing the elbow provide dynamic stability.16,17 As described by O’Driscoll et al,18 the combination of static and dynamic stabilizers provides primary and secondary constraints that prevent elbow instability. Primary constraints are the ulnohumeral articulations, the medial collateral ligaments (especially the anterior bundle), and the lateral collateral ligament complex (especially the lateral ulnar collateral ligament). The secondary constraints are the ra-
diohumeral articulations, the common flexor-pronator tendons, the common extensor tendons, and the capsule. The proximal radioulnar joint articulation contains the radial notch of the ulna, the lesser sigmoid notch of the ulna, and the rim of the radial head. A main component of the secondary constraints of the elbow, the radiocapitellar articulation contains the concave surface of the radial head and the capitellum of the distal humerus. The ulnotrochlear articulation is a main part of the primary constraints of the elbow. It contains the sagittal ridge and greater sigmoid notch of the ulna and the trochlea of the humerus. In full flexion of the elbow, the coronoid process locks into the coronoid fossa of the distal humerus to provide more stability. Stability in full extension is provided by the olecranon as it rotates into the olecranon fossa of the humerus. Capsuloligamentous stabilizers include the anterior and posterior joint capsule, and the medial and lateral collateral complex.16 The anterior capsule extends from the proximal margin of the coronoid fossa to the edge of the coronoid process distally and to the annular ligament laterally. The posterior capsule extends from the proximal edge of the olecranon fossa to the proximal edge of the medial and lateral greater sigmoid notch, and merges laterally with the annular ligament. The ulnar (or medial) collateral complex contains the anterior bundle, the posterior bundle, and the
transverse ligament. The anterior bundle originates at the anteroinferior surface of the medial epicondyle and inserts on the sublime tubercle on the anteromedial aspect of the coronoid process. The anterior bundle provides significant stability against valgus force.16 The posterior bundle is part of the thickening of the capsule rather than a ligament.16 The lateral complex consists of the radial collateral ligament, the lateral ulnar collateral ligament, the annular ligament, and the accessory collateral ligament. The radial collateral ligament and the lateral ulnar ligament share a common origin at the distal edge of the lateral epicondyle, with the radial collateral ligament inserting on to the anterior portion of the annular ligament and the lateral ulnar ligament inserting on to the posterior attachment of the annular ligament. The lateral ulnar collateral ligament is a main component of the primary constraint of the elbow that provides posterolateral and varus stability.18 The annular ligament starts at the anterior margin and ends at the posterior margin of the lesser sigmoid notch. Four muscle groups provide dynamic stability to the elbow: the elbow flexors, elbow extensors, forearm flexorspronators, and forearm extensors. The elbow flexors include the biceps, brachialis, and brachioradialis. The extensors include the triceps and the anconeus. The flexorspronators include all muscles in the anterior compartment, whereas the extensors include
those in the posterior compartment of the forearm.
Mechanisms of Terrible Triad Injuries The mechanisms of terrible triad injuries can be separated into low-energy falls from standing height and highenergy accidents. Most of the low-energy mechanisms are in those patients with poor bone quality. Approximately 60% of terrible triad injuries are the result of minor falls on an outstretched arm from standing height.3-12 One-third of cases are the result of falls from greater heights, are bicycle related, or occur in sportsrelated injuries; motor vehicle accidents account for just 6% of cases.3-12 O’Driscoll et al18 described the mechanism failure according to the “Horii” circle, where the sequential failure of softtissue constraints starts from the lateral side and moves anteriorly and posteriorly to the medial side. Although the coronoid fracture was once described as an avulsion fracture, it is now understood to most often be the result of shear forces caused by posterior translation against the humeral trochlea.19 Once the coronoid is fractured and the anterior bundle disrupted, valgus compression and radiocapitellar abutment occurs. This results in compression fractures to the radial head as the forearm dislocates posteriorly.18 The ultimate result is gross instability due to disruption of 3 of the primary and secondary static stabilizers of the elbow20—the ulnohumeral
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articulation, the anterior bundle, the lateral ulnar collateral ligament, and the coronoid as anterior bony constraint of the distal humerus.
Classification Multiple classification systems have been proposed for radial head and coronoid fractures. Mason’s21 classification of the radial head is most widely used and has been modified by others.22-24 In Mason’s21 classification, Type I describes a nondisplaced fracture of the radial head, Type II adds displacement of a partial radial head fracture, and Type III describes a comminuted fracture of the entire radial head (Figure 2). Broberg and Morrey22 further specified Mason’s system by defining Type I as fracture with less than 2-mm displacement, Type II as 2-mm or greater displacement and/ or involvement of greater than 30% of the joint surface, Type III as radial head comminution, and Type IV as a fracture with associated elbow dislocation. Hotchkiss23 further added to the classification by including treatments and outcome to differentiate nonoperative, repairable, and non-repairable injuries of the radial head. In this system, a Type I fracture is less than 2 mm displaced without block of motion and amenable to nonoperative management; a Type II fracture has mechanical block to motion, greater than 2-mm displacement, and can be viewed as repairable; and Type III is a non-repairable comminuted fracture that will require excision and replacement.23
Mason Type I is rarely associated with terrible triad injuries, accounting for just 5% of cases.3-7,10,11 The other 95% of injuries are nearly equally distributed between Mason Type II and Type III injuries (84 vs 81; P=.8).3-7,10,11 Although few studies have used the Broberg and Morrey system for classification of radial head injuries in terrible triad injuries, there appears to be a similar distribution pattern. An attempt at radial head reconstruction in fractures with more than 3 fragments is thought to result in poorer outcomes relative to radial head replacement.25 Regan and Morrey’s26 system is 1 of the 2 common classification systems for coronoid fractures, the other being the classification according to O’Driscoll et al. In the Regan and Morrey classification, Type 1 coronoid fractures involve only the coronoid tip. Type 2 describes a single or comminuted fracture involving less than 50% of the coronoid height. Type 3 is a single or comminuted fracture involving greater than 50% of the coronoid. The classification proposed by O’Driscoll et al27 describes 3 coronoid fractures and their respective subclasses regarding location and mechanism. Type 1 describes transverse tip fractures of the coronoid, Type 2 anteromedial facet fractures, and Type 3 coronoid base fractures. Among studies using the O’Driscoll et al system to grade coronoid injuries, Type I is the most common pattern, accounting for 92% of injuries, compared with 7% being
Figure 2: Intraoperative photographs of retrieval of the radial head fragment through a separate medial approach (A) and fragment assembly for sizing of the radial head prosthesis (B).
classified as Type II and just 1% being classified as Type III.4,6-8
Initial Evaluation Patients with terrible triad injuries are often seen after higher-energy mechanisms such as motor vehicle accidents. In addition to local symptoms such as pain, swelling, and deformity of the elbow, ipsilateral and contralateral upper-extremity fractures as well as injuries to other parts of the body can be found.3-12 A full primary and secondary trauma survey according to Advanced Trauma Life Support (ATLS) guidelines, including a full assessment of the musculoskeletal system, should be performed. Next, a full orthopedic survey should also be performed to look for other musculoskeletal injuries. Areas of deformity and ecchymosis must be noted, including open laceration at the elbow area, which may constitute an open fracture. Ipsilateral shoulder deformities or wrist tenderness can be signs of associated injuries. A neurovascular examination is mandatory before and after reductions or manipulation. The ulnar nerve is the most vulnerable and commonly injured nerve in complex elbow trauma.21,23
Reduction should be attempted with the arm in supination to help the coronoid process clear the trochlea. In addition, coronal displacement as well as posterior displacement must be corrected by posterior to anterior application of pressure on the olecranon tip while flexing the elbow to obtain reduction.18 A terrible triad injury, like other elbow fracture-dislocations, can also distend anterior structures in the antecubital fossa, including the brachial artery. This has been reported but rarely leads to ischemia and compartment syndrome.24
Diagnostic Imaging Standard radiographs of the elbow are mandatory before and after reduction (Figure 1). Concentric reduction of the ulnohumeral and radiocapitellar joints must be verified. Although conventional radiographs obtained after elbow reduction allow injury assessment and planning, especially in terrible triad injuries, computed tomography (CT) can facilitate detailed fracture visualization, including involvement of the coronoid process and the radial head. Threedimensional CT reconstruction of the elbow can complement preoperative planning.
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Treatment Nonoperative Treatment Recurrent instability is a hallmark of terrible triad injuries,1 and surgical management is indicated for most patients medically fit for operation.3-15,28 A small subset of patients who maintain concentric reduction of a terrible triad injury with stable range of motion to approximately 30° of extension may be amenable to conservative treatment. These cases usually have coronoid tip avulsions (Type 1) with nondisplaced and mechanically not blocking radial head fractures. In this setting, both a functional examination under fluoroscopy and CT are important to fully understand the extent of injury and to confirm the nonoperative treatment. Operative Treatment Surgical fracture fixation and ligament reconstruction is the treatment of choice in the majority of terrible triad injuries. Approaches. Lateral or medial approaches as well as a single posterior midline incision as a global approach can be used.29 Most terrible triad injuries can be repaired using a lateral approach only. When using a posterior global approach, bilateral full-thickness fasciocutaneous flaps are raised, allowing access to both the medial and the lateral aspects of the elbow. Traumatic ruptures of fascial and capsular structures are commonly found. These traumatic windows can facilitate access; often, however, they need to be extended using standard deep approach-
es to visualize key structures. On the lateral side, inspection of the radial head is usually achieved using Kocher’s30 interval between the anconeus and the extensor carpi ulnaris, with the common extensor origin elevated anteriorly to provide visualization of the lateral ulnar collateral ligament injury. An arthrotomy is then made or extended along the anterior border of the lateral ulnar collateral ligament to allow assessment of the radial head injury.30 If necessary, increased exposure of the radial head can be gained by extending the Kocher interval proximally via anterior reflection of the common extensor origin from the lateral humerus,29 or by an additional approach through Kaplan’s interval between the extensor carpi radialis longus and the extensor digitorum communis.29,31 If the radial head is deemed appropriate for fixation, then the coronoid process is approached from the medial side. If a radial head excision and replacement is indicated, the radial head fragments are excised and used for prosthesis sizing before approaching the coronoid laterally through the defect. As in lateral dissection, a traumatic window can be used for the medial approach. If it is insufficient for assessment of the coronoid fracture, then the Hotchkiss medial “over the top” approach between the flexor-pronator origin and brachialis and the flexor carpi ulnaris and triceps can be used. Reconstructive Strategy. Algorithm-driven approaches can help standardize surgical strategy. After determining the
type of surgical approach, it is important to decide whether the radial head fracture is considered technically repairable. If it is, then open reduction and internal fixation is attempted. If the radial head is comminuted with greater than 3 fragments or presents subacutely, then radial head replacement is generally performed. The decision regarding salvage or replacement directs the surgical approach to the coronoid process: if the radial head is excised, the resulting defect allows an approach to the coronoid from the lateral side, which spares a separate medial incision. In cases where the radial head is reconstructed, a separate medial approach is recommended. In the majority of cases, the medial collateral ligament is not repaired. Most authors recommend medial collateral complex repair only when, after radial head and coronoid process repair as well as lateral ulnar collateral ligament reconstruction, the elbow remains unstable. Finally, in cases where, even after mediolateral reconstruction of bony and ligamentous restraints, the elbow remains unstable, a hinged external fixator is indicated, which can restore congruent and stable early elbow motion5,6,11,15 (Figure 3). Static external fixators or temporary Steinmann pins can be used if a dynamic hinged fixator is unavailable. Static treatment should not exceed 3 weeks because significant stiffness can occur then. Coronoid and Radial Head Repair. Several techniques are available for repair of the coronoid process, depending
on fragment size and surgeon preference. Transosseous FiberWire (Arthrex, Inc, Naples, Florida) sutures, passed either freehand or using a targeting device through the ulnar, grasp the anterior capsule and coronoid tip and can provide good stability.13 In larger coronoid fragments, cannulated headless compression screws or suture anchors may also be used. Larger Type II and Type III fragments, as well as anteromedial fractures, may be repaired with plate fixation, which is often facilitated by medial exposure. After fixation of the coronoid, anterior capsule, or both, the radial head is repaired or replaced, based on prior assessment. Plate fixation of radial head or neck fractures needs to be positioned in the so-called “safe zone”—the nonarticular portion of the radial head—to avoid impingement during rotation.32 This area lies on the lateral aspect of the radial head if the forearm is held in neutral rotation. Modular radial head prostheses allow intraoperative customization of stem, neck, and head sizes for optimal fit. When sizing the neck length, the implanted head should project proximal to lesser sigmoid articulation.14,33 In some cases, it may be necessary to excise greater portions of the radial neck to ensure optimal fit and avoid overstuffing of the radiocapitellar joint (Figure 2). Ligament Repair and Closure. Following repair or replacement of the radial head, the lateral ulnar collateral ligament, which is usually avulsed
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off the lateral epicondyle, needs to be reattached using suture anchors or transosseous sutures passed through ulnar drill holes. Drill holes should tunnel through the insertion of the lateral ulnar collateral ligament on isometric point on the center of the lateral epicondyle (Figure 3); improper placement of the humeral tunnels may reduce stability or restrict motion.11 Care must be taken when tensioning the lateral ulnar collateral ligament to not over tighten the lateral side in cases of medial collateral complex instability. Placing the medial collateral complexdeficient, unstable elbow in supination when tightening the lateral ulnar collateral ligament can minimize this problem. Following repair of the lateral ulnar collateral ligament, the elbow is tested through a range of flexion from 30° to 120° under fluoroscopy to assess for stability as well as ulnar nerve traction if a medial approach was used for coronoid repair. Repair of the anterior bundle of the medial collateral ligament is not necessary if the elbow is stable following lateral ulnar collateral ligament repair,6,11 but can be indicated for persistent instability.11 Prophylactic ulnar nerve decompression or transposition at initial treatment is optional and up to the surgeon to prevent postoperative ulnar nerve dysfunction.6-8 Persistent instability or incongruent reduction despite lateral ulnar collateral ligament and medial collateral ligament repair will call for either static or dynamic external fixation. An
Figure 4: Clinical photograph 2 weeks postoperatively demonstrating the healed lateral approach and the clinical aspect of a hinged external fixator assembly.
Figure 3: Postoperative anteroposterior (A) and lateral (B) radiographs demonstrating concentric reduction of the ulnohumeral joint in a hinged external fixator and lateral ulnar collateral ligament reinsertion using an anchor and radial head replacement.
alternate strategy is placement of a hinged fixator without medial collateral ligament repair. Further research is needed to refine the treatment algorithm.
Postoperative Care and Complications Patients receive a long arm splint for temporary soft-tissue rest in 90° of elbow flexion. Supervised rehabilitation begins within the first week and is guided by the extent of the surgical procedure and the achieved elbow stability. Active extension and flexion in a hinged elbow brace is initiated to usually 30° of terminal extension. Mobilization proceeds during the first 6 to 8 weeks, increasing the motion arc by 10 degrees per week. Progressive nighttime extension splinting can facilitate extension. Forearm rotation is permitted at this time in 90° of elbow flexion, protecting medial collateral ligament and lateral ulnar collateral ligament repairs. Hinged external fixators are usually removed after 4 weeks.
Two case examples are illustrated in Figures 1 through 8. Case 1 demonstrates an acute presentation of a terrible triad injury with a comminuted radial head that was replaced. Coronoid process and lateral ulnar collateral ligament reconstruction ensued as well as a hinged external fixator to permit early mobilization. The case was instrumented from the lateral side, except for a medial incision to retrieve a displaced radial head piece. The medial collateral
complex was not repaired; instead, a hinged external fixator was placed and early active motion begun (Figures 1-4). Case 2 demonstrates a delayed presentation of a terrible triad injury (Figures 5-8). A global posterior approach was used in this case. Figure 8 shows the full functional outcome in this case. Complications include instability as well as stiffness, infection, pain, ulnar neuropathy, malunion, nonunion, heterotopic ossification arthrosis, osteoarthritis, and contracture.3,10,11,34 Re-operation is necessary in as many as 28% of patients.11,13 Instability is thought to be more common in smaller avulsiontype coronoid fractures, possi-
Figure 5: Preoperative anteroposterior (A) and lateral (B) radiographs of a 45-year-old patient presenting with elbow pain 4 weeks after injury. Subluxation of the ulnohumeral joint, radial head fracture, and coronoid avulsion are seen.
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Figure 6: Intraoperative photographs demonstrating the posterior global approach (A) and the excised radial head fragments (B). This was a nonreconstructable radial head injury.
Figure 7: Postoperative anteroposterior (A) and lateral (B) radiographs showing the hinged external fixator as well as radial head replacement and lateral ulnar collateral ligament reconstruction. Transosseous drill holes for coronoid refixation are visible.
ally described as having a poor long-term prognosis, good and excellent results have been achieved with increased understanding of elbow anatomy and physiology. Surgical treatment is the standard of care when concentric stable reduction cannot be achieved. A standardized approach to reconstruct bony and ligamentous anatomy is necessary to achieve the goal of early mobilization. Ongoing research must answer the many open questions in the treatment of these severe injuries.
Figure 8: Clinical photographs taken 12 weeks after injury demonstrating functional forearm rotation (A, B) as well as extension-flexion (C, D).
bly due to the more challenging fixation. Although loosening of radial head prostheses has been well described, newer designs as well as modular components may improve biomechanical
performance and prosthetic survival.11,12
1. Hotchkiss RN. Fractures and dislocations of the elbow. In: Court-Brown C, Heckman JD, Koval KJ, Wirth MA, Tornetta P, Bucholz RW, eds. Rockwood and Green’s Fractures in Adults. Philadelphia, PA: Lippincott-Raven; 1996.
2. van Riet RP, Morrey BF. Documentation of associated injuries occurring with radial head fracture. Clin Orthop Relat Res. 2008; 466(1):130-134.
Although terrible triad injuries have been tradition-
3. Chemama B, Bonnevialle N, Peter O, Mansat P, Bonnevialle
P. Terrible triad injury of the elbow: how to improve outcomes? Orthop Traumatol Surg Res. 2010; 96(2):147-154. 4. Doornberg JN, Ring D. Coronoid fracture patterns. J Hand Surg Am. 2006; 31(1):45-52. 5. Egol KA, Immerman I, Paksima N, Tejwani N, Koval KJ. Fracture-dislocation of the elbow: functional outcome following treatment with a standardized protocol. Bull NYU Hosp Jt Dis. 2007; 65(4):263-270. 6. Forthman CM, Henket M, Ring DC. Elbow dislocation with intra-articular fracture: the results of operative treatment without repair of the medial collateral ligament. J Hand Surg Am. 2007; 32(8):12001209. 7. Jeong WK, Oh JK, Hwang JH, Hwang SM, Lee WS. Results of terrible triads in the elbow: the advantage of primary restoration of medial structure. J Orthop Sci. 2010; 15(5):612-619. 8. Lindenhovius AL, Jupiter JB, Ring D. Comparison of acute versus subacute treatment of terrible triad injuries of the elbow. J Hand Surg Am. 2008; 33(6):920-926. 9. Pai V, Pai V. Use of suture anchors for coronoid fractures in the terrible triad of the elbow. J Orthop Surg (Hong Kong). 2009; 17(1):31-35. 10. Seijas R, Ares-Rodriguez O,
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Orellana A, Albareda D, Collado D, Llusa M. Terrible triad of the elbow. J Orthop Surg (Hong Kong). 2009; 17(3):335-339. 11. Watters TS, Garrigues GE, Ring D, Ruch DS. Fixation versus replacement of radial head in terrible triad: is there a difference in elbow stability and prognosis? Clin Orthop Relat Res. 2014; 472(7):2128-2135. 12. Winter M, Chuinard C, Cikes A, Pelegri C, Bronsard N, de Peretti F. Surgical management of elbow dislocation associated with non-reparable fractures of the radial head. Chir Main. 2009; 28(3):158-167. 13. Garrigues GE, Wray WH III, Lindenhovius ALC, Ring DC, Ruch DS. Fixation of the coronoid process in elbow fracturedislocations. J Bone Joint Surg Am. 2011; 93(20):1873-1881. 14. Leigh WB, Ball CM. Radial head reconstruction versus replacement in the treatment of terrible triad injuries of the elbow. J Shoulder Elbow Surg. 2012; 21(10):1336-1341. 15. Zeiders GJ, Patel MK. Man agement of unstable elbows following complex fracturedislocations: the “terrible triad”
injury. J Bone Joint Surg Am. 2008; 90(suppl 4):75-84. 16. Levangie PK, Norkin CC. Joint Structure and Function: A Comprehensive Analysis. Philadelphia, PA: F. A. Davis; 2005. 17. Youm Y, Dryer RF, Thambyrajah K, Flatt AE, Sprague BL. Biomechanical analyses of forearm pronation-supination and elbow flexion-extension. J Biomech. 1979; 12(4):245-255. 18. O’Driscoll SW, Morrey BF, Korinek S, An K-N. Elbow subluxation and dislocation: a spectrum of instability. Clin Orthop Relat Res. 1992; (280):186197. 19. Cage DJ, Abrams RA, Callahan JJ, Botte MJ. Soft tissue attachments of the ulnar coronoid process: an anatomic study with radiographic correlation. Clin Orthop Relat Res. 1995; (320):154-158. 20. O’Driscoll SW, Jupiter JB, King GJW, Hotchkiss RN, Morrey BF. The unstable elbow. J Bone Joint Surg Am. 2000; 82(5):724-738. 21. Mason ML. Some observations on fractures of the head of the radius with a review of one hundred cases. Br J Surg. 1954;
42(172):123-132. 22. Broberg MA, Morrey BF. Results of treatment of fracturedislocations of the elbow. Clin Orthop Relat Res. 1987; (216):109-119. 23. Hotchkiss RN. Displaced fractures of the radial head: internal fixation or excision? J Am Acad Orthop Surg. 1997; 5(1):1-10. 24. Johnston GW. A follow-up of one hundred cases of fracture of the head of the radius with a review of the literature. Ulster Med J. 1962; 31:51-56. 25. Ring D. Displaced, unstable fractures of the radial head: fixation vs. replacement—what is the evidence? Injury. 2008; 39(12):1329-1337. 26. Regan W, Morrey BF. Classification and treatment of coronoid process fractures. Orthopedics. 1992; 15(7):845-848. 27. O’Driscoll SW, Jupiter JB, Cohen MS, Ring D, McKee MD. Difficult elbow fractures: pearls and pitfalls. Instr Course Lect. 2003; 52:113-134. 28. Guitton TG, Ring D. Nonsurgically treated terrible triad injuries of the elbow: report of four cases. J Hand Surg Am. 2010;
35(3):464-467. 29. Patterson SD, Bain GI, Mehta JA. Surgical approaches to the elbow. Clin Orthop Relat Res. 2000; (370):19-33. 30. Kocher T. Operations at the elbow. In: Kocher T, ed. Textbook of Operative Surgery. London: Adam and Charles Black; 1911:313-318. 31. Kaplan EB. Surgical approach to the proximal end of the radius and its use in fractures of the head and neck of the radius. J Bone Joint Surg Am. 1941; (23):86-92. 32. Smith GR, Hotchkiss RN. Radial head and neck fractures: anatomic guidelines for proper placement of internal fixation. J Shoulder Elbow Surg. 1996; 5(2 pt 1):113-117. 33. Doornberg JN, Linzel Zurakowski D, Ring D. erence points for radial prosthesis size. J Hand Am. 2006; 31(1):53-57.
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34. Rodriguez-Martin J, PretellMazzini J, Andres-Esteban EM, Larrainzar-Garijo R. Outcomes after terrible triads of the elbow treated with the current surgical protocols: a review. Int Orthop. 2011; 35(6):851-860.
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