Osteology of the coronoid process with clinical correlation to coronoid fractures in terrible triad injuries

Biomechanical evaluation of the modified lasso technique

BACKGROUND

The Terrible Triad of the elbow is a constellation of elbow dislocation, radial head fracture and coronoid process fracture. A common type of coronoid fracture documented with this triad is type II Regan-Morrey coronoid fractures. The preferred fixation method for this fracture type is the lasso technique, medial-lateral tunnel orientation being the traditional approach. Considering elbow anatomy, we saw an opportunity to potentially improve fixation by altering the suture lasso tunnel orientation to a proximal-distal orientation.

HYPOTHESIS

Two tunnels in the proximal-distal direction would result in greater biomechanical stability as compared to the traditional lasso technique.

MATERIAL AND METHODS

A type 2 Regan-Morrey fracture was created in 12 fresh frozen cadaveric elbows at 50% of the coronoid height using an oscillating saw. The humero-ulnar joint was placed in 0 degrees flexion then loaded at a rate of 10mm/min to failure.

RESULTS

The control technique (medio-lateral tunnels) showed failure load of 150±81N that was not significantly different (p=0.825) than the 134±116N measured for the modified technique (distal-proximal tunnels). The portion of the load-displacement curve used to calculate stiffness was linear (R^2=0.94±0.04) with determination coefficients that did not differ between the two groups (p=0.351). For stiffness, we measured 17±13N/mm and 14±12N/mm respectively for control and modified techniques that did not result in a significant difference (p=0.674).

CONCLUSION

In this attempt to improve the shortcomings of the lasso technique, we found that changing from medio-lateral to proximal-distal drilling directions did not result in an appreciable biomechanical benefit.

LEVEL OF EVIDENCE

Basic science study; Biomechanics.

"How the Wrightington classification of traumatic elbow instability can simplify the algorithm for treatment"

There are numerous injury patterns of elbow-fracture dislocation that can lead to confusion about the best surgical management. The Wrightington classification aims to provide a simple categorization based on the injury to the coronoid process and the three column concept of the elbow osseous stability that describes a medial column consisting of the anteromedial coronoid facet and sublime tubercle, the middlecolumn is the anterolateral coronoid facet, and the lateral column is the radial head and lateral ligament complex with a fulcrum for varus/valgus stability between the two coronoid facets. Injuries are classified as type A (anteromedial facet/medial-column), B (bifacet/ medial and middle-columns), B+ (bifacet with radial head/all three columns), C (combined radial head and anterolateral facet/middle and lateral-columns), D (distal to coronoid where coronoid is in continuity with olecranon process), and D+ (distal to coronoid with radial head fracture). With each bony injury pattern, we can anticipate which soft tissue constraints are likely to be involved and the importance of their repair to restore stability, and thereby develop algorithms for management. The Wrightington classification has been shown to be reliable and valid. A consecutive series of 60 patients with elbow-fracture dislocation managed according to the surgical algorithms of the Wrightington classification have been reported to have excellent outcomes with a median Mayo Elbow Performance Score of 100 (interquartile 85-100) and flexion/extension arc of movement of 123° (interquartile 101°-130°). In conclusion, the Wrightington classification of elbow-fracture dislocation is a comprehensive, reliable, and valid classification with treatment algorithms that are associated with good functional outcomes.

Morphological Characteristics of Proximal Ulna Fractures: A Proposal for a New Classification and Agreement for Validation

Historically, proximal ulna fractures have been simplistically diagnosed and treated as simple olecranon fractures, leading to an unacceptable number of complications. Our hypothesis was that the recognition of lateral, intermediate, and medial stabilizers of the proximal ulna and ulnohumeral and proximal radioulnar joints would facilitate decision-making, including the choice of approach and type of fixation. The primary aim was to propose a new classification for complex fractures of the proximal ulna based on morphological characteristics seen on three-dimensional computed tomography (3D CT). The secondary aim was to validate the proposed classification regarding its intra- and inter-rater agreement. Three raters with different levels of experience analyzed 39 cases of complex fractures of the proximal ulna using radiographs and 3D CT scans. We presented the proposed classification (divided into four types with subtypes) to the raters. In this classification, the medial column of the ulna involves the sublime tubercle and is where the anterior medial collateral ligament is inserted, the lateral column contains the supinator crest and is where the lateral ulnar collateral ligament is inserted, and the intermediate column involves the coronoid process of the ulna, olecranon, and anterior capsule of the elbow. Intra- and inter-rater agreement was analyzed for two different rounds, and the results were evaluated according to Fleiss kappa, Cohen kappa, and Kendall coefficient. Intra- and inter-rater agreement values were very good (0.82 and 0.77, respectively). Good intra- and inter-rater agreement attested to the stability of the proposed classification among the raters, regardless of the level of experience of each one. The new classification proved to be easy to understand and had very good intra- and inter-rater agreement, regardless of the level of experience of each rater.

Greater sigmoid notch dysplasia causing elbow instability: Lateral ligament reconstruction and Stamp osteotomy

The coronoid is one of the elbow's primary static stabilisers, and the importance of reconstruction following fracture with instability has been established. In the developing elbow, instability can lead to greater sigmoid notch dysplasia that can make reconstruction challenging. A novel technique to improve osseous stability with an opening wedge 'stamp osteotomy' reconstruction of the coronoid is described combined with a lateral ligament reconstruction, in two patients with recurrent posteromedial rotatory instability. The technique improves congruity and coverage of the greater sigmoid notch with the trochlea whilst maintaining articular cartilage. Extra-articular iliac crest bone graft is used to maintain the position with buttress plate support. The surgical technique is described and the clinical and radiographic outcome reported in two patients. Level of evidence: IV.

Computed tomography analysis of the relationship between the coronoid and the radial head

BACKGROUND

The coronoid process is an important stabilizer of the elbow, and its anatomy has been extensively studied. However, data documenting the relationship of the coronoid relative to the radial head (RH) are limited. The latter is a good landmark for the surgeon when débriding or reconstructing the coronoid. This imaging-based study quantified the anatomic relationship between the coronoid and the proximal radius and ulna.

METHODS

We investigated 80 cadaveric upper extremities (18 paired elbows) by 3-dimensional digital analysis of computed tomography data. After construction of a standardized coordinate system, the relationships between the coronoid, the anterior-most point of the RH, the deepest point of the articular surface of the RH, the top of the lesser sigmoid notch, and the deepest point of the guiding ridge of the trochlear notch were analyzed.

RESULTS

The mean height of the tip of the coronoid was 36 ± 4 mm (range, 26-43 mm). The mean height of the anterior-most point of the RH was 40 ± 4 mm (range, 28-47 mm). The mean distance between the tip of the coronoid and the anterior-most point of the RH was 4.5 ± 1 mm (range, 2-10 mm). For paired elbows, the heights of the tip of the coronoid and the anterior-most point of the RH were similar between sides.

CONCLUSION

This study described the relationship between the coronoid and RH. This information should prove useful when reconstructing a coronoid from a medial approach in the case of an intact RH. The difference in radiographic height between the tip of the coronoid and anterior RH in the normal elbow averages 5 mm. However, when we account for the normal cartilage thickness of the RH and coronoid, a 3- to 6-mm difference in height would be seen at surgery depending on whether the cartilage of the coronoid process is intact or removed. The distance between the tip of the coronoid and the anterior-most point of the RH is similar to the size of shavers used when débriding osteophytes during arthroscopy.

Dislocations of the elbow - An instructional review

Dislocations of the elbow require recognition of the injury pattern followed by adequate treatment to allow early mobilisation. Not every injury requires surgery but if surgery is undertaken all structures providing stability should be addressed, including fractures, medial and lateral ligament insertion and the radial head. The current concepts of biomechanical modelling are addressed and surgical implications discussed.

Current concepts in elbow fracture dislocation

BACKGROUND

Elbow fracture dislocations are complex injuries that can provide a challenge for experienced surgeons. Current classifications fail to provide a comprehensive system that encompasses all of the elements and patterns seen in elbow fracture dislocations.

METHODS

The commonly used elbow fracture dislocation classifications are reviewed and the three-column concept of elbow fracture dislocation is described. This concept is applied to the currently recognised injury patterns and the literature on management algorithms.

RESULTS

Current elbow fracture dislocation classification systems only describe one element of the injury, or only include one pattern of elbow fracture dislocation. A new comprehensive classification system based on the three-column concept of elbow fracture dislocation is presented with a suggested algorithm for managing each injury pattern.

DISCUSSION

The three-column concept may improve understanding of injury patterns and treatment and leads to a comprehensive classification of elbow fracture dislocations with algorithms to guide treatment.

Posteromedial rotatory instability of the elbow: What the radiologist needs to know

Varus posteromedial rotatory instability of the elbow joint is a relatively new subject described for the first time in 2003. It occurs secondary to axial loading of the elbow with varus force and internal rotation of the forearm. There is usually a specific pattern of osseous and soft tissue injuries that can be recognized on imaging. This includes an anteromedial coronoid fracture and avulsion of the lateral collateral ligament complex from its humeral attachment. Ulnar collateral ligament complex injury is also reported, particularly its posterior bundle which plays an important role in posteromedial elbow joint stability. There is high incidence of early osteoarthritis secondary to the resultant varus instability and increased contact pressure at the ulnohumeral joint. Surgical fixation of the coronoid fracture and ligamentous reconstruction maybe indicated to prevent this recurrent instability. The article reviews the key radiological features of posteromedial rotatory instability with multiple examples from different imaging modalities. The relevant anatomy of the elbow joint stabilising structures will be illustrated, in particular the coronoid process anatomy and the O'Driscoll classification for coronoid process fractures. Radiologists should be familiar with the imaging findings of posteromedial rotatory instability.

Surgical Selection of Unstable Intertrochanteric Fractures: PFNA Combined with or without Cerclage Cable

Due to the instability of unstable intertrochanteric fractures, the selection of a suitable internal fixation has always been a challenge for orthopedic surgeons. This study is aimed at comparing the clinical efficacy of PFNA combined with cerclage cable and without cerclage cable and finally recommend a stable internal fixation method to provide the basis for clinical therapy. From January 2014 to January 2018, we retrospectively analyzed all cases of unstable intertrochanteric fractures who received treatment in the Orthopedics Department of our hospital and finally screened 120 cases, 51 of whom were treated with cerclage cable, 69 without cerclage cable. The follow-up period was one year. HHS, BI, and RUSH scores were given within the specified time. We divided the patients into the PFNA+cable (PFNA combined with cerclage cable) group and the PFNA group. The time of fracture healing and weight-bearing in the PFNA+cable group was shorter than that in the PFNA group. With regard to HHS, BI, and RUSH, the PFNA+cable group was higher than the PFNA group at 1 month, 3 months, 6 months, and 12 months after operation. For HHS rating, the PFNA+cable group has a higher excellent rate than the PFNA group, which was 96.1% and 84.1%, respectively. All the results mentioned above were statistically significant. Compared with the group without cerclage cable, the application of cerclage cable can reduce the incidence of complications. From the comparison between the two groups, it can be seen that the surgical method of PFNA combined with cerclage cable can not only help to improve the stability of fracture reduction, shorten the time of fracture healing and postoperative weight-bearing, and significantly improve patients' self-care ability but also reduce the incidence of postoperative complications. Therefore, we think PFNA combined with cerclage cable is a good choice.

[Treatment of ulnar coronoid process fracture via a modified anteromedial approach]

Objective

To investigate the effectiveness of a modified anteromedial approach in the treatment of ulnar coronoid process fracture.

Methods

Between February 2017 and July 2018, 15 patients with ulna coronoid process fracture were reviewed. There were 9 males and 6 females, with an average age of 42.3 years (range, 24-60 years). The causes of injury included falling in 10 cases and traffic accidents in 5 cases, all cases were closed injury. According to the O'Driscoll classification, there were 4 cases of type Ⅰ, 6 cases of type Ⅱ, and 5 cases of type Ⅲ. The time from injury to operation was 2-8 days (mean, 3.7 days). All fractures were treated via a modified anteromedial approach between the pronator teres and the flexor carpi radialis plus with partial incision of flexor tendon aponeurosis. The fracture healing, muscle strength of forearm, postoperative complications were observed. At last follow-up, the elbow mobility were measured, the function of elbow was evaluated by Mayo elbow performance score (MEPS).

Results

All cases were followed up 10-18 months (mean, 13.3 months). Fracture union was achieved in all patients with a mean time of 10 weeks (range, 8-14 weeks). No obvious decrease of hand grip strength, nerve injury, and infection occurred. One patient had slight heterotopic ossification without special treatment. At last follow-up, all patients had stable elbows with good flexion-extension and varus-valgus stability, the mean flexion was 123.3° (range, 100°-140°), mean extension loss compared with that before operation was 6.7° (range, 0°-20°), mean pronation was 76.0° (range, 60°-85°), and mean supination was 75.8° (range, 55°-90°). The MEPS score was 65-100 (mean, 90.3) with the result of excellent in 10 cases, good in 4 cases, and fair in 1 case.

Conclusion

The treatment of ulnar coronoid process fracture via the modified anteromedial approach provides excellent exposure, minimal invasion, fewer complications, and satisfactory prognosis, which is conducive to elbow joint function recovery.

Buttress plate fixation of coronoid process fractures via a medial approach

PURPOSE

To assess the clinical and radiographic outcomes of coronoid process fractures surgically managed with buttress plate fixation via a medial approach.

METHODS

A retrospective review of all coronoid fractures surgically fixed in our institution using a buttress plate technique via a medial approach between June 2012 and April 2015 by the senior author was performed. These fractures were all sizeable fractures contributing to persistent elbow instability in terrible triad or varus posteromedial rotatory instability injury patterns. A prospective telephone questionnaire was conducted to assess patient outcomes using the disabilities of the arm, shoulder and hand (DASH) score and Mayo hlbow performance score (MEPS).

RESULTS

Twelve patients were included in the study, comprising 10 males and 2 females with an average age of 39 years (range, 19-72 years). Mean follow-up was 16 months (range, 4-18 months). The average time to radiographic union was 4 months (range, 3-7 months). Range of motion measurements at final follow-up were obtained in 11 out of 12 patients, with one patient defaulting follow-up. All 11 patients displayed a functional elbow range of motion of at least 30°-130°, with an average arc of motion of 130° (range, 110° -140°), mean elbow flexion of 134° (range, 110° -140°) and mean flexion contracture of 3° (range, 0° -20°). The mean DASH score was 16 (range, 2.5-43.8) and the mean MEPS was 75 (range, 65-100). Complications observed included one patient with a superficial wound infection which resolved with a course of oral antibiotics and one patient with radiographic evidence of heterotopic ossification which was conservatively managed. No residual elbow instability was observed and no reoperations were performed.

CONCLUSION

Buttress plate fixation via a medial approach of coronoid process fractures that contribute to persistent elbow instability represents a reliable method of treatment that produces satisfactory and predictable outcomes.

Quantitative measurements of facets on the ulnar coronoid process from reformatted CT images

Background

To quantify the size and angle of the medial and lateral facets of the ulnar coronoid process by reformatted computed tomography (CT) imaging.

Methods

Elbow CT images were retrospectively selected from the picture archiving and communication system in our hospital over a 5-year period (January 2011 to December 2015). The widths, heights, gradient and tilt angles of both the medial and lateral facet of the ulnar coronoid process were measured using two-dimensional (2D) reformations of CT images.

Results

Our database research yielded 120 elbow joints (53 right, 67 left) of 120 patients (54 males, 66 females) which fulfilled our criteria. The average width of the two facets of the ulnar coronoid process were 13.34±1.85 mm for the medial facet and 8.39±1.29 mm for the lateral facet. The average height of the medial facet was 18.45±3.38 mm and the lateral facet was 17.55±3.81 mm. The average tilt angles of medial and lateral facet were 80.34°±7.71° and 98.78°±5.71° respectively. The average gradient angles of the medial and lateral facet ridge were 60.02°±8.78° and 36.97°±4.99° respectively. The length of the lateral facet ridge was longer than the medial facet ridge.

Conclusions

Reformatted CT images allow for multiple, accurate measurements of facets on the ulnar coronoid process. These measurements can be applied to guiding appropriate surgical interventions for fractures in this area.

Complex coronoid and proximal ulna fractures are we getting better at fixing these?

Technological advances and improved understanding of functional anatomy about the elbow have lead an evolution regarding operative reconstruction of complex proximal ulnar and coronoid fractures. When treating these complex and challenging fractures, goals of anatomic articular restoration along with balanced soft tissue stability can lead to early range of motion and thus, desired functional outcome. The purpose of this review is to outline and provide tips and pearls to achieve desired results, with a comprehensive update on the most recent literature to support the latest fixation methods and techniques.

The ulnar greater sigmoid notch "coverage angle": bone and cartilage contribution. Magnetic resonance imaging anatomic study on 78 elbows

BACKGROUND

To study the degree of coverage provided by the greater sigmoid notch (GSN) to the humeral trochlea, as well as the contribution of the olecranon and coronoid process cartilage tips to this angle, and its variations.

METHODS

We recruited 39 healthy volunteers, comprising 19 women and 20 men, with a mean age of 28 years (range, 21-32 years). High-definition magnetic resonance images were obtained for the right and left elbows. Four angles were measured on the sagittal plane passing through the coronoid and olecranon tips: angle A, identified by 2 lines from the trochlea center to the olecranon bone-cartilage junction and olecranon cartilage tip; angle B, identified by 2 lines from the trochlea center to the olecranon and coronoid bone-cartilage junction; angle C, identified by 2 lines from the trochlea center to the coronoid bone-cartilage junction and coronoid cartilage tip; and GSN coverage angle (GSN-ca), defined as the sum of angles A, B, and C. Pearson correlation tests, t tests, and intraclass correlation coefficients were used for statistical analyses.

RESULTS

The mean angle A, angle B, and angle C values were 6° (range, 2°-12°), 182° (range, 153°-204°), and 9° (range, 2°-16°), respectively. No correlations were found between these 3 angles. The mean GSN-ca was 198° (range, 167°-222°), and the GSN-ca was less than 180° in 8% of the cases. No significant differences emerged for side or gender or for total length of the ulna.

CONCLUSION

The GSN showed significantly different shapes on the sagittal plane that we defined as closed type when the GSN-ca was greater than 180° (92%) and as open type when the GSA-ca was less than 180° (8%). The cartilage tip contribution varied and was not correlated with that of bone.

An original internal fixation technique by tension band wiring with steel wire in fractures of the coronoid process

Fractures of the coronoid process, which is a key element in anterior elbow joint stability, represent 14% of proximal ulnar fractures. Optimal treatment should stabilize all fractures associated with elbow instability. Different techniques have been described: suture repair, screws, plates… We propose a series of 5 patients who were treated with an original, easy, tension band wiring fixation technique using steel wire with easy hardware removal.

Single-staged treatment using a standardized protocol results in functional motion in the majority of patients with a terrible triad elbow injury

BACKGROUND

Terrible triad injuries of the elbow, defined as elbow dislocation with associated fractures to the radial head and coronoid, are associated with stiffness, pain, and loss of motion. Studies to date have consisted of small sample sizes and used heterogeneous surgical techniques, which render comparisons difficult and unreliable.

QUESTIONS/PURPOSES

In a group of patients treated under a standard surgical protocol, we sought to determine the early dislocation rate, the range of motion in those not undergoing secondary procedures, the frequency and types of secondary surgical interventions required, the difference in motion between those undergoing secondary surgery and those who did not, and the frequency of heterotopic ossification and patient-reported stiffness.

METHODS

Patients underwent a surgical protocol that involved fixing the coronoid, fixing the radial head if possible, otherwise performing radial head arthroplasty, and repairing the lateral ligamentous structures. Patients were excluded if ipsilateral upper extremity fractures from the humerus to the distal forearm were present. Fifty-two patients had a minimum followup of 6 weeks and were included for the early dislocation rate, and 34 of these (65%) had a minimum of 6 months followup and were included for the rest of the data. Eighteen of the 52 (35%) were considered lost to followup because they were seen for less than 6 months postsurgically and were excluded from further analysis. Chart review was performed to determine the presence of early dislocation within the first 6 weeks after surgery, range of motion in patients not requiring a secondary procedure, the frequency and types of secondary procedures required, the range of motion before and after a secondary procedure if it was required, and postoperative stiffness. Postoperative radiographs were analyzed to determine the presence and severity of heterotopic ossification.

RESULTS

One of 52 patients sustained a dislocation within the first weeks of surgery (1.9%). Those not undergoing a secondary procedure were able to achieve a flexion arc of 110° and a supination-pronation arc of 148°. Nine of 34 patients (26%) underwent a secondary surgical procedure with stiffness, heterotopic ossification, and ulnar neuropathy being the most common surgical indications. Before secondary surgical procedures, patients had a flexion arc of 57° and a supination-pronation arc of 55°, which was less than those only requiring primary surgery alone (p < 0.001). After secondary surgery, patients were able to achieve a flexion arc of 96° and a supination-pronation arc of 124°, which was not different from those who did not undergo reoperation (p = 0.09 and p = 0.08, respectively). Twenty-eight of 34 patients demonstrated evidence of heterotopic ossification on radiographs, whereas 20 patients, including all nine undergoing secondary procedures, reported stiffness at the elbow.

CONCLUSIONS

Using a standardized surgical protocol, a low early dislocation rate was observed, although stiffness remains a challenge. Many patients who initially do not attain functional range of motion can usually attain this after secondary procedures aimed at removing the heterotopic ossification.

LEVEL OF EVIDENCE

Level IV, therapeutic study. See guidelines for authors for a complete description of levels of evidence.

Use of fine-threaded K-wires in the treatment of coronoid fractures in complex elbow instability

The coronoid process is one of the main elbow constraints that provides ulnohumeral joint stability. Coronoid fractures may be fixed using multiple techniques, including transosseous sutures, screws, and plates. The goal of this study was to analyze the clinical and radiographic outcomes in a series of patients with complex elbow instability in whom coronoid fractures were repaired using fine-threaded K-wires. Eight men and 10 women (mean age, 47 years) were followed prospectively for a mean of 26 months. Surgical treatment consisted of open reduction and internal fixation of all fractures; radial head replacement in Mason III injuries; lateral collateral ligament repair in all patients; and, in cases of persistent instability, medial collateral ligament repair, hinged fixator application, or both. Coronoid fixation was performed using 2 or more fine-threaded K-wires, depending on the fragment size, inserted from the posterior aspect of the ulna and directed toward the coronoid fragment using a 1-step fixation technique. At last follow-up, mean extension was 15°, mean flexion was 133°, mean pronation was 78°, and mean supination was 69°; mean Disabilities of the Arm, Shoulder and Hand score was 9.7, mean American Shoulder and Elbow Surgeons score was 85, and mean Mayo Elbow Performance Score was 89. According to the Mayo Elbow Performance Index, 10 excellent, 7 good, and 1 fair result were recorded. All but 1 patient had a stable elbow. Fracture healing was observed in all but 1 patient. No secondary coronoid fragment dislocation or implant failures were reported. This study shows that using fine-threaded K-wires provides easy, minimally invasive, stable, and successful 1-step fixation that can be used to obtain osteosynthesis of coronoid fractures in patients with complex elbow instability.