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abstractFull article available online at Healio.com/Orthopedics. Search: 20121120-18

The types and prevalence of soft tissue constraint injuries associated with complex el-bow instability have been rarely investigated. The purpose of this study was to analyze the intraoperative findings of soft tissue constraint injuries in complex elbow instability and provide a comprehensive classification of these lesions. Forty-seven patients un-dergoing surgery for complex elbow instability were prospectively analyzed. Ligament injuries were classified as simple or complex lesions, depending on whether the liga-ment was damaged at a single zone or 2 to 3 zones, including its proximal, middle, and distal portions. Posterolateral capsule injuries were classified as small or large in the presence of capsular avulsions smaller than or larger than 1 cm, respectively. The presence of lesions of the common extensor and flexor–pronator muscles were also recorded. Ligament injuries were found in 96% of patients. The lateral collateral ligament showed a simple lesion, including a proximal and distal avulsion, in 19% and 2% of patients, respectively, and a middle-zone tear in 13%. Complex lesions, including the association of a middle-zone tear with a proximal or distal avulsion, were found in 47% and 6% of patients, respectively, and a combination of proximal, distal, and middle-zone injuries in 4%. Small and large posterolateral capsule lesions were found in 49% and 17% of patients, respectively. A medial collateral ligament injury was present in 45% of patients. A high prevalence of soft tissue constraint le-sions was found to be associated with complex elbow instability. Soft tissue constraint status should be carefully evaluated pre- and intraoperatively in patients with complex elbow instability. The classification reported herein may be helpful in planning the proper treatment of these complex injuries.

Drs Giannicola, Polimanti, Sacchetti, Scacchi, Gumina, Greco, and Cinotti are from the Department of Anatomical, Histological, Forensic Medicine and Orthopaedics Sciences, “Sapienza” University of Rome, Rome, Italy.

Drs Giannicola, Polimanti, Sacchetti, Scacchi, Gumina, Greco, and Cinotti have no relevant finan-cial relationships to disclose.

Correspondence should be addressed to: Giuseppe Giannicola, MD, Department of Anatomical, Histological, Forensic Medicine and Orthopaedics Sciences, “Sapienza” University of Rome, Via Emilio Repossi 15, 00158 Rome, Italy (giannicola.giuseppe@gmail.com).

doi: 10.3928/01477447-20121120-18

Soft Tissue Constraint Injuries in Complex Elbow Instability: Prevalence, Pathoanatomy, and ClassificationGiuseppe Giannicola, MD; DaviD poliManti, MD; FeDerico M. sacchetti, MD; Marco scacchi, MD; steFano GuMina, MD; alessanDro Greco, MD; Gianluca cinotti, MD

Figure: Intraoperative photograph of the lateral compartment exposed through the Kocher interval showing a lateral collateral ligment type P lesion. The detached origin of the lateral collateral ligment is raised by the clamp. The middle zone of the lat-eral collateral ligment is intact (arrowhead). The extensor carpi ulnaris muscle (asterisk) and anco-neus muscle (double asterisk) are shown.

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Complex elbow instability consists of 1 or more osteoarticular frac-tures associated with capsular,

ligamentous, and muscle-tendinous inju-ries leading to a loss of elbow stability.1-4 They include severe injuries of the upper limb requiring challenging reconstructive surgeries, the results of which may be un-predictable.5-8

The stability of the elbow joint is pro-vided by primary stabilizer structures, including soft tissue constraints (ie, lat-eral and medial collateral ligaments) and bony constraints (ie, coronoid process, olecranon, and humeral trochlea), which equally contribute to elbow stability.9-13 Secondary stabilizers of the elbow are the radiohumeral joint, anterior and posterior joint capsule, and epitrochlear and epi-condyle muscle-tendinous units.9,10,14,15 Elbow instability occurs when 2 or more primary stabilizers of the joint are injured; it may further worsen when lesions of sec-ondary stabilizers are associated.2,3,9,11

Although soft tissue constraint injuries are a consistent finding in complex elbow instability,1-4 little is known about the pathoanatomic changes of soft tissue con-straint structures associated with complex elbow instability. In the only retrospec-tive study on lateral ligamentous damage in elbow dislocations, the authors did not distinguish between ligaments damage found in simple and complex elbow insta-bilities.16 Two other studies documented medial collateral ligament injuries in simple elbow dislocations, but the series analyzed did not include patients with complex elbow instability.17,18

The purposes of the current perspec-tive study were to analyze the prevalence and pathoanatomic features of soft tissue constraint lesions found intraoperatively in patients with complex elbow instability and to design a comprehensive classifica-tion of these injuries.

Materials and MethodsAccording to Italian law, the authors

were not required to ask for institutional

review board or ethical committee ap-proval for this type of study. However, each author certifies that his or her insti-tution approved the human protocol for this study and that the study was conduct-ed in conformity with ethical principles of research.

Between January 2005 and December 2008, forty-seven patients underwent surgery for complex elbow instability. Patients with previous injuries or elbow surgeries were excluded. The patients included 24 men and 23 women with a mean age of 54.6 years (range, 22-75 years). Twenty-seven injuries were the re-sult of a fall from a standing height, 11 the result of a motor vehicle accident, 5 the result of a fall from a greater height, and 4 the result of sports activities. The left arm was involved in 24 patients and the right in 23. Preoperative diagnosis included a Monteggia-like lesion in 17 patients, a terrible triad in 13, a comminuted radial head fracture associated with posterior el-bow dislocation in 6, a capitulum humeri and trochlea fracture with posterior dislo-cation in 6, a coronoid fracture associated with posterior dislocation in 3, and a tran-solecranon fracture–dislocation in 2.

Patients with elbow dislocation un-derwent closed reduction and spica cast immobilization in the emergency depart-ment. No patient had an irreducible dis-location. High-quality radiographs and computed tomography (CT) scans, includ-ing 2- and 3-dimensional reconstructions, were obtained in all cases. Surgical treat-ment was performed a mean of 3 days (range, 1-7 days) after trauma. All surger-ies were performed by a single surgeon (G.G.) in a 1-step procedure. No patient had multiple injuries or open fractures requiring further surgical procedures or temporary stabilization with external fixa-tion. A posterior or extended posterolateral skin incision was used in all patients. The Kocher interval was used to expose the lateral compartment while an over-the-top approach or, alternatively, the elevation of flexor–pronator muscles from the subcuta-

neous and medial border of the ulna was accomplished to expose the medial com-partment. In all patients, the lateral com-partment was exposed, and the presence of any injury involving the common extensor origin, lateral collateral ligament complex, and posterolateral joint capsule was identi-fied. Medial collateral ligament status was assessed in all patients with intraoperative valgus–pronation stress testing at 30° of flexion under fluoroscopy; a medial col-lateral ligament tear was diagnosed when the medial joint space increased more than 2 mm during the test.19 In patients with persistent elbow instability after open re-duction and internal fixation and lateral compartment reconstruction, the medial compartment was exposed and the status of flexor–pronator origin and medial col-lateral ligament directly visualized. The medial compartment was also exposed for internal fixation of anteromedial coronoid fractures.

Soft tissue injuries observed intraopera-tively were jointly assessed by 2 operating surgeons (G.G., G.C.) and recorded with a digital camera. The collected images were then reassessed by 3 orthopedic surgeons (F.M.S., S.G., A.G.) who were not present at the surgery.

Intraoperative findings showed that lateral collateral ligaments and medial collateral ligaments were injured in dif-ferent zones of the ligament, including their proximal, middle, and distal por-tions. Because such injuries occurred as either isolated or joint lesions, they were classified as simple (ie, a single zone was damaged) or complex lesions (ie, injury involved 2 or 3 portions of the same liga-ment). Simple lesions were subclassified into 3 types: type P (proximal), a lesion located within 1 cm from its humeral inser-tion; type M (middle-zone), a lesion located 1 cm or more distal to its humeral origin or proximal to its ulnar insertion; and type D (distal), a lesion located within 1 cm from its ulnar insertion. In some patients, a bony avulsion was found to be associated with the ligament injury. It usually involved, on

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the lateral side, the lateral epicondyle or the supinator crest and, on the medial side, the inferior part of medial epicondyle and sublime tubercle. When the avulsed bone fragment was larger than 5 mm, it was re-corded as BF (bone fragment). As a result, types P and D were further classified as type P-BF and D-BF when associated with a detached bone fragment.

Complex lesions included a combi-nation of simple lesions: type PM (type P1type M), a proximal avulsion associ-ated with a middle-zone lesion; type DM (type D1type M), a distal avulsion as-sociated with a middle-zone lesion; and type PMD (type P1type M1type D), an entirely torn ligament. Type PM and DM were further classified as PM-BF and DM-BF when associated with a bone fragment.

Posterolateral capsule injuries were classified as small or large, depending on whether the capsular detachment from the posterolateral aspect of the distal humerus adjacent to the lateral collateral ligament origin was smaller than or larger than 1 cm, respectively. Posterolateral capsule lesions were further classified as type small-BF and large-BF when associated with an avulsed bone fragment smaller or larger than 5 mm. To describe injuries of common extensor and flexor–pronator muscle origin, the criteria of McKee et al16 were used; these injuries were diag-nosed in the presence of a lack of tendon continuity greater than 50%. Because the medial compartment was exposed only in patients in whom the medial collateral ligament or anteromedial coronoid frac-ture was reconstructed, the type of injury of flexor–pronator origin was assessed in only these patients. The types of injuries included in the soft tissue constraint clas-sification are shown in Figures 1 through 3.

Statistical Analysis Inter- and intraobserver reliability of

classification was assessed in 25 random-ly selected patients by 3 surgeons who were asked to classify each soft tissue

constraint injury based on intraoperative images. Three weeks later, a second eval-uation was performed; the order of initial images was randomly changed to gener-ate a new sequence. Data were collected on spreadsheets and the k coefficient was used to assess agreement.20

resultsLigament lesions were found in 45

(96%) patients. In the remaining 2 (4%) patients, both of whom had a transolec-ranon fracture–dislocation, no ligament injury occurred. Two patients with a Bado I Monteggia-like lesion had an isolated annular ligament injury. In one of these patients, the annular ligament torn was in-terposed in the proximal radioulnar joint, preventing the reduction of the radial head. In the other patient, a middle-zone lesion in the anterior portion of the annular ligament was observed.

Lateral Collateral Ligament InjuriesLateral collateral ligament tears were

found in 43 (91%) patients. Proximal avulsions were found in 31 (66%) patients (Figures 4, 5); 7 (15%) were type P, 22 (47%) were type PM, and 2 (4%) were type P-BF. In all cases, the proximal avul-sion was associated with a posterolateral capsule lesion.

Lateral collateral ligament type M lesions were found in 6 (13%) patients and type D in 1 (2%). The latter was as-sociated with a bony avulsion of the su-pinator crest and thus classified as type D-BF (Figure 6). A type DM lesion was observed in 3 (6%) patients. A type PMD disruption of the lateral collateral ligament was observed in 2 (4%) patients (Figure 7). The prevalence of lateral col-lateral ligament lesions found in differ-ent complex elbow instability patterns is shown in Table 1.

Medial Collateral Ligament InjuriesMedial collateral ligament tears were

noted under fluoroscopy in 21 (45%) pa-tients. In 6 (29%) of these patients, the

medial collateral ligament was exposed intraoperatively, showing an avulsion from its humeral origin in 4 (19%) cases. The remaining 2 (10%) patients exhibited a ligament avulsion from its ulnar inser-tion, associated in 1 (5%) case with a sub-lime tubercle fragment. In all 6 patients, the lesion was classified as complex be-cause a concomitant middle-zone tear was found. As a result, 4 (19%) cases were classified as type PM (Figure 8), 1 (5%) as type DM, and 1 (5%) as type DM-BF. Medial collateral ligament tears were ob-served more frequently in terrible triads (61%), distal humerus shear fracture–dis-locations (67%), and coronoid fracture–dislocations (66%) than in other complex elbow instability patterns (Table 2).

Posterolateral Capsule, Common Extensor, and Flexor–Pronator Muscle Origin Injuries

Posterolateral capsule lesions were observed in 31 (66%) patients. They were classified as small in 23 (74%) cases, large in 7 (23%), and large-BF in 1 (3%) (Figure 9). Large posterolateral capsule lesions were always associated with anco-neus detachment from the humeral inser-tion. Posterolateral capsule lesions were observed more frequently in terrible triads (69%) and Monteggia-like lesions (70%) than in other complex elbow instability patterns. Injuries of the common extensor muscle origin were present in 10 (21%) patients and were always associated with complex lateral collateral ligament lesions (Figure 7). This lesion was observed more frequently in terrible triads (54%) than in other complex elbow instability patterns. The flexor–pronator muscle origin was damaged in 2 (33%) of the 6 cases as-sessed intraoperatively. The frequency of medial collateral ligament, posterolateral capsule, common extensor, and flexor–pronator muscle origin injuries found in different complex elbow instability pat-terns is shown in Table 2.

The interobserver reliability of classi-fication was good, with a k value of 0.72

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(range, 0.56-0.82), whereas the intraob-server reliability was excellent, with a k value of 0.85 (range, 0.78-0.94).

discussionAlthough the presence of soft tissue

constraint lesions may increase the com-

plexity of reconstructive surgery and com-promise the surgical outcomes in patients with complex elbow instability, little is

Figure 1: Classification of lateral collateral ligment (LCL) injuries. Abbreviations: D, distal; D-BF, distal with bone fragment; DM, distal1middle zone; DM-BF, distal1middle zone with bone fragment; M, middle zone; P, proximal; P-BF, proximal with bone fragment; PM, proximal1middle zone; PM-BF, proximal1middle zone with bone fragment; PMD, proximal1middle zone1distal.

1

Figure 2: Classification of medial collateral ligament (MCL) injuries. Abbreviations: D, distal; D-BF, distal with bone fragment; DM, distal1middle zone; DM-BF, distal1middle zone with bone fragment; M, middle zone; P, proximal; P-BF, proximal with bone fragment; PM, proximal1middle zone; PM-BF, proximal1middle zone with bone fragment; PMD, proximal1middle zone1distal.

2

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known about their prevalence and patho-anatomic features. McKee et al16 retro-spectively analyzed the operative records of 62 elbow injuries, including simple and complex elbow instabilities, and re-ported 6 patterns of pathoanatomical le-sions. The most frequent type of lateral collateral ligament injury observed was

a proximal avulsion (52%), followed by a midsubstance rupture (29%) and a hu-meral condylar avulsion fracture (8%). Common extensor origin disruptions and medial collateral ligament tears were observed in more than half of cases, and distal soft tissue avulsions, proximal ul-nar avulsions, and a combined pattern of

the previous types were found in 12% of cases. However, the authors did not distin-guish between the results of patients with simple and complex elbow instabilities or report what type of complex elbow insta-bility was present. In addition, the intra-operative findings may have been biased by the long time interval between trauma

Figure 3: Classification of posterolateral capsule (PLC) and muscle-tendinous origin injuries. Abbrevia-tions: BF, bone fragment; CEO, common extensor origin; FPO, flexor–pronator origin.

3

Figure 4: Intraoperative photograph of lateral compartment exposed through the Kocher interval showing a lateral collateral ligment type P lesion. The detached origin of the lateral collateral ligment is raised by the clamp. The middle zone of the lat-eral collateral ligment is intact (arrowhead). The extensor carpi ulnaris muscle (asterisk) and anco-neus muscle (double asterisk) are shown.

4

Figure 5: Intraoperative photograph of lateral compartment exposed through the Kocher interval showing a lateral collateral ligment proximal avul-sion associated with a middle-zone tear, classified as type PM. The clamp raises the detached origin of the lateral collateral ligment. The middle-zone tear (arrowheads), radial head (arrow), and lateral epicondyle (asterisk) are shown.

5Figure 6: Intraoperative photograph of lateral compartment exposed through the Kocher interval showing a lateral collateral ligment distal avulsion, classified as type D-BF. The clamp raises the de-tached insertion of the lateral collateral ligment. The radial head (arrow), bony avulsion of the su-pinator crest (arrowhead), and lateral epicondyle (asterisk) are shown.

6Figure 7: Intraoperative photograph of lateral compartment exposed through the Kocher interval showing a complete disruption of the lateral collat-eral ligment (type PMD) with a concomitant rupture of the common extensor tendon. The radial head (arrow), common extensor tendon injury (arrow-heads), and lateral epicondyle with proximal lateral collateral ligment avulsion (asterisk) are shown.

7

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and surgery (average, 15 days; range, 1-76 days). Nevertheless, to the authors’ knowl-edge, no other studies have reported intra-operative findings or pathologic changes involving soft tissue constraint structures in patients with complex elbow instabil-ity. The current study reports elbow soft tissue constraint injures observed in a

large series of patients with complex el-bow instability. Each lesion was evaluated intraoperatively by 2 orthopedic surgeons and thereafter reassessed on digitalized images by 3 independent examiners.

The results showed that the lateral collateral ligament complex was the soft tissue structure most frequently injured;

it was found to be damaged in all but 2 patients. Conversely, medial collateral ligament tears were observed in approxi-mately half of the cases. Only 2 patients in this series, both of whom had transolecra-non fracture–dislocations, had no soft tis-sue constraint lesions present, confirming that, in these injuries, ligament damage is

Table 1

LCL Complex Lesions for Each Pattern of Complex Elbow Instability

No.

Complex Elbow Instability Pattern

Type P

Type M

Type D

Type PM

Type DM

Type PMD Total

Terrible triad (n513) 1 1 1BF 8 0 2 13

Radial head fracture–dislocation (n56)

1 2 0 3 0 0 6

Monteggia-like lesion (n517)

5 (1BF)

1 0 7 2 0 15

Distal humerus shear fracture–dislocation (n56)

1 2 0 2 1 0 6

Transolecranon fracture–dislocation (n52)

0 0 0 0 0 0 0

Coronoid fracture–dislocation (n53)

1BF 0 0 2 0 0 3

Total 9 6 1 22 3 2 43

Abbreviations: BF, bone fragment; D, distal; DM, distal1middle zone; LCL, lateral collateral ligament; M, middle zone; P, proximal; PM, proximal1middle zone; PMD, proximal1middle zone1distal.

Figure 8: Intraoperative photograph of medial compartment exposed through the Hotchkiss ap-proach showing a medial collateral ligament proxi-mal avulsion associated with a midsubstance tear, classified as type PM. The clamp raises the de-tached origin of the medial collateral ligament. The medial collateral ligament reversed (arrowhead), medial epicondyle (asterisk), and flexor carpi ulna-ris (double asterisk) are shown.

8

Figure 9: Intraoperative photograph taken after posterior exposure of the elbow and after ulnar os-teosynthesis in a Monteggia-like lesion. The pos-terolateral capsule is detached from the posterolat-eral aspect of the humerus with a bone fragment. This lesion was classified as posterolateral capsule large-BF lesion. The posterolateral aspect of the humerus (asterisk) and posterolateral capsule with bone avulsion (arrowhead) are shown.

9

Table 2

CEO, MCL, and PLC Lesions for Each Pattern of Complex Elbow Instability

Complex Elbow Instability Pattern

No.

CEO MCL PLC6Small PLC6Large Total

Terrible triad (n513) 7 8 4 5 24

Radial head fracture–dislocation (n56)

2 2 3 1 BF 8

Monteggia-like lesion (n517) 0 5 11 1 17

Distal humerus shear fracture–dislocation (n56)

0 4 3 0 7

Transolecranon fracture–dislocation (n52)

0 0 0 0 0

Coronoid fracture–dislocation (n53)

1 2 2 1 6

Total 10 21 23 8 62

Abbreviations: BF, bone fragment; CEO, common extensor origin; MCL, medial collateral ligament; PLC, posterolateral capsule.

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rare and osteosynthesis of an ulnar fracture is usually sufficient to restore elbow joint stability.2,4,21,22

In contrast with a previous investi-gation,16 the current authors found that complex ligament lesions (ie, 2 or 3 por-tions of the same ligament damaged) were present in a relevant percentage (57%) of patients with complex elbow instability. For example, in lateral collateral ligament injures, a proximal or distal avulsion was associated with a tear of the middle zone of the ligament in 73% of cases. Complex ligament lesions should be distinguished from simple ligament injuries, in which an isolated portion of the ligament is disrupted, because they usually require a more complex reparative surgery.23 Based on this assumption, the authors designed a comprehensive classification of the differ-ent types of soft tissue constraint injures. In particular, in addition to simple lesions of the collateral ligaments (types P, M, and D),16 complex ligament lesions (types PM, DM, and PMD) are also classified because they are likely to require differ-ent reconstructive procedures. For exam-ple, when the lesion is located more than 1 cm from ligament insertions (ie, in the middle zone of the ligament), a side-to-side suture is usually indicated, whereas in the presence of a ligament tear occur-ring within 1 cm from its insertion, a bony reinsertion technique should be used. The classification also includes the presence of bony avulsions greater than 5 mm be-cause, in that case, a different ligamentous repair technique may be needed.23

Lateral collateral ligament injuries were distinguished from posterolateral capsule lesions, and the latter were further classi-fied into small and large lesions because they usually require different treatments. Small posterolateral capsule lesions are easily repairable during lateral collateral ligament reinsertion at the epicondyle and further treatments are rarely necessary, whereas large posterolateral capsule le-sions often require specific surgical proce-dures, including the positioning of suture

anchors on the posterior aspect of the capi-tellum or on the lateral border of olecra-non.23 Large posterolateral capsule lesions were also found to be associated, in all cas-es, with anconeus detachment. Because the anconeus muscle is a secondary stabilizer of the elbow,24,25 it should be repaired when the lateral collateral ligament is severely damaged, a condition that was frequently observed in the current series.

Several studies have reported the clini-cal and biomechanical relevance of sec-ondary stabilizers of the elbow, includ-ing capsule and common extensor and flexor origin muscles.9,10,14,15 The entity of muscular damage has been correlated with the tendency to redislocate under anesthesia,18 and flexor–pronator muscle mass plays a role in elbow valgus stabil-ity.14 In the current series, a common ex-tensor origin tear was observed in 21% of cases. It was always accompanied by a posteromedial lesion of the lateral col-lateral ligament and by a posterolateral capsule injury, suggesting that lateral soft tissue constraints are likely to be detached sequentially from the lateral condyle dur-ing a posterolateral dislocation.16

In the current series, soft tissue con-straint injures showed a different prevalence in each pattern of complex elbow instability. Medial collateral ligament tears were ob-served more frequently in terrible triads, hu-meral shear fracture–dislocations, and coro-noid fracture–dislocations. Posterolateral capsule lesions were observed more fre-quently in terrible triads and Monteggia-like lesions, whereas common extensor origin injuries were more frequent in terrible triads than in other complex el-bow instability patterns. However, such differences were not statistically signifi-cant, likely due to the limited sample size, which did not allow definitive conclusions to be drawn.

This study had some limitations. A relatively small number of patients was re-ported for each complex elbow instability pattern. Furthermore, because the medial collateral ligament was explored intraop-

eratively only when necessary (eg, when elbow instability persisted after recon-struction of the lateral collateral ligament complex), data on the types and severities of medial collateral ligament injures are in-complete and need to be further investigat-ed. However, this is the first study prospec-tively analyzing the pathoanatomy of acute soft tissue constraint lesions in patients with complex elbow instability. In addi-tion, because a short time interval occurred between trauma and surgery, it was pos-sible to identify several pathologic changes involving elbow soft tissue constraint not previously described.

conclusionComplex elbow instability is consid-

ered a challenging condition, even for ex-pert elbow surgeons. The diagnosis of a lesion involving primary and secondary el-bow constraints, which may be encoun-tered in complex elbow instability, is cru-cial to performing an accurate joint recon-struction and planning an adequate reha-bilitation program.1-4 A comprehensive and reproducible classification of these injuries may be useful to guide surgeons in the re-constitution of soft tissue constraints of the elbow joint and to compare the results of different surgical techniques. Further stud-ies with larger series of patients are needed to evaluate whether the reported classifica-tion may achieve these goals.

references 1. Morrey BF. Complex instability of the elbow.

Instr Course Lect. 1998; 47:157-164.

2. Ring D, Jupiter JB. Fracture–dislocation of the elbow. Hand Clin. 2002; 18(1):55-63.

3. Morrey BF. Current concepts in the manage-ment of complex elbow trauma. Surgeon. 2009; 7(3):151-161.

4. Giannicola G, Sacchetti FM, Greco A, Cinotti G, Postacchini F. Management of complex elbow instability. Musculoskelet Surg. 2010; 94(suppl 1):S25-S36.

5. Broberg MA, Morrey BF. Results of treat-ment of fracture–dislocations of the elbow. Clin Orthop Relat Res. 1987; (216):109-119.

6. Ring D, Jupiter JB, Simpson NS. Monteggia fractures in adults. J Bone Joint Surg Am. 1998; 80(12):1733-1744.

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7. Pugh DM, Wild LM, Schemitsch EH, King GJ, McKee MD. Standard surgical protocol to treat elbow dislocations with radial head and coronoid fractures. J Bone Joint Surg Am. 2004; 86(6):1122-1130.

8. Konrad GG, Kundel K, Kreuz PC, Oberst M, Sudkamp NP. Monteggia fractures in adults: long-term results and prognostic factors. J Bone Joint Surg Br. 2007; 89(3):354-360.

9. Morrey BF, An KN. Articular and ligamen-tous contributions to the stability of the elbow joint. Am J Sports Med. 1983; 11(5):315-319.

10. Morrey BF, Tanaka S, An KN. Valgus stabil-ity of the elbow. A definition of the primary and secondary constraints. Clin Orthop Relat Res. 1991; (265):187-195.

11. O’Driscoll SW, Jupiter JB, King GJ, Hotchkiss RN, Morrey BF. The unstable el-bow. Instr Course Lect. 2001; 50:89-102.

12. Deutch SR, Jensen SL, Tyrdal S, Olsen BS, Sneppen O. Elbow joint stability following experimental osteoligamentous injury and re-construction. J Shoulder Elbow Surg. 2003; 12(5):466-471.

13. Morrey BF, An KN. Stability of the elbow: osseous constraints. J Shoulder Elbow Surg. 2005; 14(1 suppl S):S174-S178.

14. Park MC, Ahmad CS. Dynamic contribu-tions of the flexor–pronator mass to elbow valgus stability. J Bone Joint Surg Am. 2004; 86(10):2268-2274.

15. Seiber K, Gupta R, McGarry MH, Safran MR, Lee TQ. The role of the elbow mus-culature, forearm rotation, and elbow flex-ion in elbow stability: an in vitro study. J Shoulder Elbow Surg. 2009; 18(2):260-268.

16. McKee MD, Schemitsch EH, Sala MJ, O’ Driscoll SW. The pathoanatomy of later-al ligamentous disruption in complex elbow instability. J Shoulder Elbow Surg. 2003; 12(4):391-396.

17. Johansson O. Capsular and ligament inju-ries of the elbow joint. A clinical and ar-thrographic study. Acta Chir Scand. 1962; (suppl 287):1-159.

18. Josefsson PO, Johnell O, Wendeberg B. Ligamentous injuries in dislocations of the elbow joint. Clin Orthop Relat Res. 1987; (221):221-225.

19. Berquist TH. Diagnostic imaging of the elbow. In: Morrey BF, ed. The Elbow and Its Disorders. 4th ed. Philadelphia, PA: Saunders; 2009:92.

20. Cohen J. A coefficient of agreement for nominal scales. Educ Psychol Meast. 1960; 20(1):37-46.

21. Ring D, Jupiter JB, Sanders RW, Mast J, Simpson NS. Transolecranon fracture– dislocation of the elbow. J Orthop Trauma. 1997; 11(8):545-550.

22. Mouhsine E, Akiki A, Castagna A, et al. Transolecranon anterior fracture dislo-cation. J Shoulder Elbow Surg. 2007; 16(3):352-357.

23. Giannicola G, Polimanti D, Sacchetti FM, et al. Soft tissue constraint injuries in com-plex elbow instability: surgical techniques and clinical outcomes. Orthopedics. 2012; 35(12):e1746-e1753.

24. Basmajian JV, Griffin WR Jr. Function of anconeus muscle. An electromyograph-ic study. J Bone Joint Surg Am. 1972; 54(8)1712-1714.

25. Molinier F, Laffosse JM, Bouali O, Tricoire JL, Moscovici J. The anconeus, an active lateral ligament of the elbow: new anatomi-cal arguments. Surg Radiol Anat. 2011; 33(7):617-621.

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