Terrible Triad Injury Research Articles

Waste Not, Want Not: A Case of a Terrible Triad Injury of the Elbow Where a Non Salvageable Radial Head Was Used as a Source of Bone Graft for a Contra Lateral Intra-Articular Distal Radius Fracture

Waste Not, Want Not: A Case of a Terrible Triad Injury of the Elbow Where a Non Salvageable Radial Head Was Used as a Source of Bone Graft for a Contra Lateral Intra-Articular Distal Radius Fracture

Results of treatment of terrible triad injury of the elbow

Background/aim A complex elbow dislocation with associated radial head and coronoid process fractures was named the terrible triad by Hotchkiss because of historically poor outcomes. This study aimed at assessing the results and functional outcome of treatment of terrible triad injuries of the elbow. Patients and methods Between 2010 and early 2013, 11 patients suffering from terrible triad injuries of the elbow were treated at Assiut University Hospitals; eight were male individuals and three were female individuals with the mean age of 43 years (range: 26–70 years). The right elbow was injured in five, and the left was injured in six patients. The radial head was replaced by a prosthesis in five and treated by internal fixation in five patients, whereas conservative treatment was decided only in one patient; the coronoid process was fixed by screws in four, whereas four were treated by suturing of the anterior capsule and were treated conservatively. Results The mean follow-up was 13.3 months (range: 6–30 months) According to the Mayo Elbow Performance Score, three patients had excellent outcome, seven had good outcome, whereas only one had fair outcome. Conclusion Prompt surgical attention with a systematic approach to restore anatomy and provide sufficient stability to allow early motion are the key factors for a successful outcome.

Risk of Subluxation or Dislocation After Operative Treatment of Terrible Triad Injuries.

The management of terrible triad injuries has evolved over the last 2 decades to include routine radial head fixation or replacement, reattachment of the lateral collateral ligament, with or without coronoid fixation. Our objective was to determine the likelihood of and factors associated with subluxation or dislocation after operative treatment of terrible triad injuries among a large group of surgeons using current techniques. Retrospective cohort study. Two level I trauma centers. A total of 107 patients with operatively treated terrible triad injuries from January 2000 to June 2015. Review of patient- and surgery-related factors during the first postoperative month. Radiographic subluxation of the ulnohumeral joint. One hundred of the 107 patients (93%) treated with open fixation of terrible triad injuries had no radiographic subluxation or redislocation. Two patients (2%) had slight transient radiographic subluxation ("drop sign") that corrected with active exercises within weeks of surgery. Five patients (5%) had persistent radiographic subluxation, 3 treated with a second surgery (3%). When treated within 2 weeks of injury, recurrent subluxation or dislocation after operative fixation of terrible triad injuries was rare (1%), provided that the radial head was replaced and the lateral collateral ligament reattached. Radiographic subluxation is very uncommon with current operative management of terrible triad injuries of the elbow within 2 weeks. Patients treated more than 2 weeks after injury might benefit from ancillary fixation to limit subluxation (ie, cross pinning, external fixation, or internal joint stabilizer). Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Comparative Analysis of Surgical Options for Medial Collateral Ligament Repair in Terrible Triad Injury of the Elbow.

The aim of our study is to evaluate the clinical and radiologic outcomes in patients with terrible triad injury, who underwent surgical treatment with or without the medial collateral ligament (MCL) repair. Fourteen patients who underwent surgery with a minimum of 12-month follow-up (mean, 17 months) were reviewed. Based on the systematic treatment protocol, radial head fracture, lateral collateral ligament, and coracoid fracture were treated. Subsequently, torn MCL was repaired in 7 patients, whereas in the remaining 7 patients, the MCL was not treated. Range of motion, elbow function, and radiographs regarding the arthrosis and heterotopic ossification were assessed. At final follow-up, no significant differences were found in elbow motion or function between the groups with and without MCL repair; except the pronation and supination which had superior range in repair group. In contrast, radiologic findings such as the arthrosis were seen more frequently in patients without MCL repair than those with repair. Our results indicate the effect of MCL repair on elbow motion and function might be small, whereas osteoarthritic changes occurred more frequently in elbows without MCL repair.

Management of the Terrible Triad Injury of the Elbow: A Case Series Retrospective Review

Objectives: To expose our experience in the multidisciplinary management of patients with terrible triad injury of the elbow (TTIE) treated in our hospital. Material and methods: A descriptive-retrospective study including all patients with TTIE treated surgically between January/2008-December/2014. The analyzed variables were demographic, etiologic, type of fracture (Mason, Reagan and Morrey Scale), type of surgery/approaching technique, time between injury-surgery, immobilization period, range-of-movement (ROM) before/after treatment, and complications. An assessment before/after the treatment using analogical visual scale (AVS), goniometry and Mayo Elbow Performance Index (MEPI) was carried out. Results: A total of 12 patients were included. The most common cause was accidental fall (75%). All fractures were surgically treated (mean 4.6 days after injury) with subsequent detention (29 days average). The surgical approach was lateral (n=8), posterior (n=2), and both lateral and medial (n=2). The increase in the flexion/extension ROM was 27.27º/24.09º, in pronation/supination was 23.65º/23.9º. The initial/final AVS was 4.46/2.16. In MEPI scale, 9 patients had excellent-good results, 2 regular, and one underwent bad response. Only one patient had complications during the follow up period. All patients were treated surgically promptly and immobilized for a month. As the MEPI states, the results of our series are acceptable. This is in accordance with present day reports. Conclusions: The clinical results of the series are consistent in relation to the literature. The results suggest that an integral, multidisciplinary approach (surgical and rehabilitation) for the TTIE must be achieved. Despite the small series and the infrequent appearance of the pathology, no cases were lost during the study.

Importance of the posterior bundle of the medial ulnar collateral ligament

There has been a renewed interest in the pathomechanics of elbow dislocation, with recent literature having suggested that the medial ulnar collateral ligament is more often disrupted in dislocations than the lateral ligamentous complex. The purpose of this serial sectioning study was to determine the influence of the posterior bundle of the medial ulnar collateral ligament (pMUCL) as a stabilizer against elbow dislocation. An elbow dislocation was simulated in 5 cadaveric elbows by mechanically applying an external rotation moment and valgus force. Medial ulnohumeral joint gapping was measured at 30°, 60°, and 90° of flexion in an intact elbow after sectioning of the medial collateral ligament's anterior bundle (aMUCL) and then after sectioning of the pMUCL as well. After sectioning of the aMUCL, the pMUCL was able to stabilize the joint against dislocation. After aMUCL sectioning, the proximal joint space significantly increased by 4.2 ± 0.6 mm at 30° of flexion and 2.6 ± 0.3 mm at 60° of flexion, although it did not dislocate. The gapping increase of 0.9 ± 0.6 at 90° of flexion did not reach significance. After sectioning of the pMUCL (after having already sectioned the aMUCL), all of the specimens frankly dislocated at all flexion angles. An intact pMUCL can prevent elbow dislocation and limited joint subluxation to within 6.6 mm. Our findings indicate that repair or reconstruction may be warranted in certain circumstances (ie, residual instability after operative management of a terrible triad injury or after aMUCL reconstruction).

Radial Head Fractures Treated with Modular Metallic Radial Head Replacement: Outcomes at a Mean Follow-up of Eight Years.

Radial head arthroplasty is commonly used to treat acute unreconstructible radial head fractures. The purpose of this study was to report on the clinical and radiographic outcomes at a minimum follow-up of five years after radial head arthroplasty with a modular metallic implant for the treatment of acute radial head fractures. The cases of fifty-five patients with unreconstructible radial head fractures treated acutely with a smooth-stemmed modular metallic radial head implant were retrospectively reviewed. A wide variety of injuries, which ranged from isolated radial head fractures to so-called terrible triad injuries, were included. All patients returned for an interview, physical examination, and radiographic evaluation at a mean of eight years (range, five to fourteen years) postoperatively. Elbow and forearm motion, elbow strength, and grip strength were measured. Radiographs were evaluated, and validated patient-rated outcome questionnaires were completed. A longitudinal subgroup analysis was performed for thirty-three patients who were previously evaluated at two years postoperatively. At a mean of 8.2 ± 2.9 years, the mean arc of flexion (and standard deviation) of the affected elbow was 11° ± 14° to 137° ± 15°. Elbow strength and motion were significantly diminished compared with the unaffected elbow (p < 0.05). The mean Mayo Elbow Performance Index (MEPI) was 91 ± 13 points. Twenty-five patients (45%) had stem lucencies; twenty-one (38%), ulnohumeral arthritis; and twenty (36%), heterotopic ossification, including one with radioulnar synostosis. Two patients underwent secondary elbow surgery, but no patient required implant removal or revision. In the subgroup evaluated longitudinally, there was a significant improvement in MEPI scores from the two-year to the eight-year follow-up (p = 0.012), with no loss of motion or strength (p > 0.05). The mid-term outcomes of radial head arthroplasty with a smooth-stemmed modular metallic prosthesis are comparable with previously reported short-term outcomes, with no evidence of functional deterioration. Radial head arthroplasty with a smooth-stemmed metallic modular implant is a good treatment option for patients with acute unreconstructible radial head fractures, and sustained clinical outcomes may be expected beyond five years of follow-up. Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Anatomic cadaveric study of the extensile extensor digitorum communis splitting approach for exposing the ulnar coronoid process

The extensile extensor digitorum communis (EDC) splitting approach can access the ulnar coronoid process (UCP), which can be used to treat terrible triad injuries. The present study anatomically examined the extensile EDC splitting approach for exposing the UCP. Twenty fresh frozen cadaveric upper limbs were dissected. The splitting length of the EDC and detachment length of the extensor carpi radialis brevis (ECRB)-extensor carpi radialis longus (ECRL)-brachioradialis (BR) origin were measured to expose the UCP. The distance between the most distal site of the EDC splitting and the point at which the posterior interosseous nerve (PIN) crosses the anterior aspect of the radial shaft, and the distance between the most proximal site of the ECRB-ECRL-BR origin detachment and the point at which the radial nerve crosses the anterior aspect of the humeral shaft were measured. The splitting length of the EDC was 45.4 ± 4.8 mm, the detachment length of the ECRB-ECRL-BR origin was 30.2 ± 4.7 mm, the distance between the distal site of the EDC splitting and PIN was 10.6 ± 6.1 mm (minimum distance, 1.1 mm), and the distance between the proximal site of the ECRB-ECRL-BR origin detachment and the radial nerve was 49.5 ± 9.7 mm (minimum distance, 31.7 mm). The extensile EDC splitting approach can sufficiently expose the UCP. However, splitting must be performed carefully because the most distal site of the EDC splitting is close to the point at which the PIN crosses the anterior aspect of the radial shaft (average distance, 10 mm; minimum distance, 1 mm).

Treatment of complex elbow fracture-dislocations.

Successful management of complex elbow fracture-dislocations requires, in part, recognition of the overall injury pattern, which can aid in the identification of concomitant bony and soft tissue injuries. Trans-olecranon fracture-dislocations are best treated surgically with stable anatomic restoration of the trochlear notch. Terrible triad elbow injuries are believed to be caused by a valgus posterolateral force. Although select terrible triad injuries can be managed non-operatively, the majority of injuries are treated with stable surgical repair to allow early elbow motion. Unlike terrible triads, varus posteromedial forces are theorized to cause anteromedial coronoid fractures. These are usually associated with LCL disruptions, but do not have concomitant MCL or radial head injuries. A subset of anteromedial coronoid fractures can also be managed non-operatively. Internal fixation is recommended for injuries associated with large fracture fragments or elbow instability preventing early motion.

Primary Hinged External Fixation of Terrible Triad Injuries and Olecranon Fracture-Dislocations of the Elbow.

This study aimed to introduce a new treatment that apples primary hinged external fixation for complex fracture-dislocations of the elbow in 12 cases. We retrospectively assessed the functional outcomes of eight patients with terrible triad injuries and three patients with an olecranon fracture-dislocation of the elbow, who were treated at our hospital using a primary hinged external fixator between June 2012 and December 2014. Ten patients underwent repair or replacement of the radial head, while three underwent repair of the olecranon. In principle, they were treated without reconstruction of the coronoid fracture and collateral ligament injury. The patients were evaluated for a mean follow-up period of 16 months after the initial surgery. Early mobilization was encouraged while the hinged external fixator was in place. At the follow-up, the mean Mayo Elbow Performance Score was 93 points; the results were "excellent" in six cases and "good" in five. No patients had recurrent elbow instability. Only one patient needed an additional procedure after the initial operation. These results suggested that primary hinged external fixation without repair of the ligament and soft tissue is an effective minimally invasive surgery for the management of terrible triad injuries and olecranon fracture-dislocations of the elbow.

肘関節Terrible Triad損傷の治療経験－鉤状突起骨折の骨接合は必須か

肘関節Terrible Triad損傷の治療経験－鉤状突起骨折の骨接合は必須か

Terrible triad of the elbow: is it still a troublesome injury?

Terrible triad injury (TTI), one of the main patterns of complex elbow instability, is difficult to treat and yields conflicting surgical results. We analyzed prospectively a series of patient affected by TTI and treated according to the current diagnostic and surgical protocols to investigate whether their application allow to obtain more predictable outcomes. We analyzed 26 patients with a mean age of 52 years. Preoperative X-rays and CT were performed; all patients were operated by the same elbow surgeon and underwent the same surgical and rehabilitation treatment. Final functional outcome was assessed by the Mayo Elbow Performance Score (MEPS), Quick-Disability of the Arm Shoulder and Hand-score (Q-DASH) and the modified-American Shoulder and Elbow Surgeons score (m-Ases). A radiographic evaluation was also performed. Mean follow-up was 31 months. At final evaluation, mean flexion, extension, supination and pronation were 137°, 10°, 77° and 79°, respectively; mean MEPS, m-ASES and Q-DASH scores were respectively 96, 91 and 8 points. Complications observed after first surgery were: elbow stiffness in 5 cases, mild posterolateral instability in 3 cases, chronic subluxation in 1 case. Radiographic evaluation showed secondary arthritis in 9 cases, symptomatic HO in 3 cases and late hardware displacement in 2 cases. Six out of 26 patient underwent reoperation with final satisfactory results. The current diagnostic and therapeutic protocols allow obtaining satisfactory clinical outcomes in majority of cases but a high number of major and minor unpredictable complications persist yet. In this series, low compliance, obesity, and extensive soft elbow tissue damage caused by high-energy trauma represented negative prognostic factors unrelated to surgery. On the other hand, the strict application of current algorithms by an expert elbow surgeon appears to improve clinical results by reducing the influence of other avoidable negative prognostic factors well known in current literature, such as the incomplete recognition of injuries, delayed treatment, inadequate treatment of bony and ligamentous injuries, prolonged immobilization and, last but not least, the surgeon's inexperience. Level IV, Case series, Treatment study.

Loop plating for ulnar coronoid fractures of Regan-Morry type I

Objective To explore the clinical efficacy of loop plating for treatment of ulnar coronoid fractures of Regan-Morry type I. Methods From January 2011 to March 2014, 42 patients with ulnar coronoid fracture of Regan-Morry type I were treated in our department. They were 31 males and 11 females, 23 to 58 years of age (mean, 39.3 years). There were 5 cases of coronoid fracture combined with elbow dislocation, 33 cases of terrible triad injury, 30 cases of comminuted coronoid process, and 12 cases of simple fractures. All the patients were treated through the Kocher approach aided by a small posterior incision. The 12 simple fractures were fixated with a loop plate after anatomic reduction. The anterior joint capsule and the brachialis muscle insertion were reconstructed with a loop plate in the 30 cases of comminuted fractures. Replacement of the radial head was performed in the 38 cases of combined radial head fracture. Anchor repair was conducted for cases combined with disruption of lateral collateral ligament. Reduction, reduction loss after loop plating, fracture healing time and complications were documented. The elbow function was evaluated at the last follow-up by Mayo elbow performance score (MEPS). Results Thirty-eight patients were followed up for 8 to 34 months (average, 25 months), and 4 patients were lost. All the 38 patients obtained bony union after 6 to 18 weeks (average, 11.8 weeks). At the last follow-up, elbow flexion ranged from 110° to 135° (average, 115°), elbow extension from 0 to 15° (average, 5°), forearm pronation from 45° to 75° (average, 70°), and supination from 68° to 94° (average, 82°). According to MEPS, 22 patients were excellent, 10 good, 2 fair, and 4 poor. The excellent to good rate was 84.2%. None of the patients had deep wound infection. Plate breakage at the radial head occurred in one case and stiff elbow in 4. One case had superficial wound infection which responded to dressing changes. Conclusions In treatment of ulnar coronoid fractures of Regan-Morry type I, loop plating can result in good efficacy because it allows reduction under direct vision, leads to rigid fixation which facilitates articular stability, and is simple as well. Key words: Elbow joint; Fracture fixation, internal; Fractures, comminuted; Ulna coronoid

Ossifications hétérotopiques après chirurgie des fractures du coude : facteurs de risque

BackgroundHeterotopic ossification (HO) is a common complication of elbow fracture surgery that can significantly impair function and range of motion (ROM). Whereas numerous studies have assessed HO after hip trauma or replacement surgery, few data have been reported on the prevalence and risk factors of HO after elbow fractures. HypothesisOur objective was to investigate the prevalence and risk factors of clinically relevant HO after elbow fracture surgery under the hypothesis that the ability to identify high-risk patients would improve treatment tailoring and assist in meeting patient expectations. Materials and methodsWe retrospectively included consecutive patients who had surgery for elbow injuries between January 2007 and December 2011. Patient demographics, operative details, and radiographs were reviewed. ResultsOf 124 elbows in 122 patients, 38 (30.6 %) had HO and 26 (21 %) clinically relevant HO. The prevalence of clinically relevant HO was highest in floating elbow injury, followed by combined olecranon and radial head fractures, types A and B distal humerus fractures, and terrible triad injury. By multiple logistic regressions, factors that independently predicted clinically relevant HO were fracture-dislocation (OR, 4.87; 95 %CI, 1.78–13.29; p=0.002) and longer time to surgery (P<0.05). Of the 26 patients with clinically relevant HO, 6 (23 %) eventually required revision elbow surgery to improve ROM. DiscussionHO of the elbow occurred in almost one-third of our patients with surgically treated elbow fractures. Fracture-dislocation of the elbow and longer time to surgery independently predicted HO responsible for ROM loss. Clinically relevant HO was associated with significant morbidity. Level of evidenceLevel IV, retrospective study.

Radial Head Ingrowth Anatomic Implant vs. Smooth Stem Monoblock Implant in Acute Terrible Triad Injury: A Prospective Study

Radial Head Ingrowth Anatomic Implant vs. Smooth Stem Monoblock Implant in Acute Terrible Triad Injury: A Prospective Study

Clinically relevant heterotopic ossification after elbow fracture surgery: A risk factors study

BackgroundHeterotopic ossification (HO) is a common complication of elbow fracture surgery that can significantly impair function and range of motion (ROM). Whereas numerous studies have assessed HO after hip trauma or replacement surgery, few data have been reported on the prevalence and risk factors of HO after elbow fractures. HypothesisOur objective was to investigate the prevalence and risk factors of clinically relevant HO after elbow fracture surgery under the hypothesis that the ability to identify high-risk patients would improve treatment tailoring and assist in meeting patient expectations. Materials and methodsWe retrospectively included consecutive patients who had surgery for elbow injuries between January 2007 and December 2011. Patient demographics, operative details, and radiographs were reviewed. ResultsOf 124 elbows in 122 patients, 38 (30.6%) had HO and 26 (21%) clinically relevant HO. The prevalence of clinically relevant HO was highest in floating elbow injury, followed by combined olecranon and radial head fractures, types A and B distal humerus fractures, and terrible triad injury. By multiple logistic regression, factors that independently predicted clinically relevant HO were fracture-dislocation (OR, 4.87; 95%CI, 1.78–13.29; P=0.002) and longer time to surgery (P<0.05). Of the 26 patients with clinically relevant HO, 6 (23%) eventually required revision elbow surgery to improve ROM. DiscussionHO of the elbow occurred in almost one-third of our patients with surgically treated elbow fractures. Fracture-dislocation of the elbow and longer time to surgery independently predicted HO responsible for ROM loss. Clinically relevant HO was associated with significant morbidity. Level of evidenceLevel IV, retrospective study.

Terrible Triad Elbow Fracture-Dislocation With Triceps and Flexor-Pronator Mass Avulsion

Terrible triad elbow injuries, consisting of fractures of the radial head and coronoid with ulnohumeral dislocation, are challenging to treat. They require a comprehensive understanding of the complex anatomy of the elbow to effectively treat all of the pathology and create a stable, congruent joint. The authors present a case of a terrible triad injury with avulsion of the triceps and flexor-pronator mass after a low-energy fall in a young patient. Although most terrible triad fracture-dislocations can be successfully treated with coronoid fixation, radial head fixation or replacement, and repair of the lateral collateral ligament complex, this case involved a completely circumferential injury to the elbow. The coronoid and anterior capsule were disrupted anteriorly, the radial head and lateral collateral ligament complex were disrupted laterally, the triceps was disrupted posteriorly, and the flexor-pronator mass was disrupted medially. Although the authors prefer to address most terrible triad injuries through a lateral approach, they suspected a circumferential injury preoperatively and elected to use a single posterior incision to address all of the pathology conveniently. This injury required treatment of all disrupted structures, because the elbow remained unstable until the triceps and flexor-pronator mass avulsions were ultimately repaired. With any elbow fracture-dislocation, surgeons should look for evidence of additional injuries that do not fit the commonly described patterns, because they may necessitate modifications to the treatment plan. Given the relatively common complications of stiffness and instability despite modern surgical techniques, additional injuries may further compromise functional outcomes unless they are addressed properly.

Management of Terrible Triad Injuries of the Elbow

ABSTRACT The term ‘Terrible Triad’ was initially coined by Hotchkiss et al to describe fracture-dislocations of the elbow involving three specific injuries: a posterolateral dislocation, coronoid fracture and radial head fracture.1 Fracture-dislocations of this type are notoriously unstable secondary to loss of the anterior buttress support from the coronoid, valgus support from the radial head, and the posterolateral stabilization of the lateral ulnar collateral ligament (LUCL).2,3 Furthermore, these injury patterns are particularly difficult to treat and have resulted in poor functional outcomes including the need for multiple reoperations.4-6 Herein, the pathoanatomy, classification, diagnosis and management of these challenging injuries will be discussed. Vovos T, Blizzard DJ, Garrigues G. Management of Terrible Triad Injuries of the Elbow. The Duke Orthop J 2015;5(1): 2834.

Terrible triad of the elbow: treatment protocol and outcome in a series of eighteen cases

The terrible triad is an uncommon injury, which includes an elbow posterior dislocation with fractures of the radial head and coronoid process of the ulna. In addition there is rupture of the lateral and medial collateral ligaments. The short-term and long term results are historically poor, with a high rate of complications. The main objective of this study is to report the results of a multicentre study of patients who sustained the terrible triad injury focusing on surgical treatment in order to offer a standardized surgical protocol.We retrospectively review the results of surgical treatment of eighteen terrible triads from a multicentre study of 226 elbow dislocations. At an average follow up of 31.5 months postoperatively, all eighteen patients returned for clinical examination, functional evaluation, and radiographs. The mean MEPS score value was 78 (25–100), which correspond to three excellent results, ten good results, three fair results, and two poor results. Five early and three late complications were reported.This particular case of elbow dislocation is very unstable and leads to many complications. The surgeon should attempt to restore stability by preserving the radial head whenever possible or replacing it with prosthesis otherwise, by repairing the lateral collateral ligament and performing fixation of the coronoid fracture. If after anatomical restoration of stability elements, the elbow remains unstable, options include repair of the medial collateral ligament or stabilization assumed by hinged external fixator.

The Effect of Capitellar Impaction Fractures on Radiocapitellar Stability

To determine the effect of capitellar impaction fractures on radiocapitellar stability in a model that simulated a terrible triad injury. Six cadaveric elbows were dissected free of skin and muscles. Tendons were preserved. The lateral collateral ligament was released and repaired (surgical control). Two sizes of capitellar impaction defects were created. After lateral collateral ligament release and repair, we then sequentially created osseous components of a terrible triad injury (partial radial head resection and coronoid fracture) through an olecranon osteotomy that was fixed with a plate. Radiocapitellar stability was recorded after the creation of each new condition. Significantly less force was required for radiocapitellar subluxation after the creation of 20° and 40° capitellar defects compared with the surgical control (intact capitellum). After the addition of a Mason type II radial head defect and then a coronoid defect, stability decreased significantly further. Impaction fractures of the distal portion of the capitellum may contribute to a loss of radiocapitellar stability, particularly in an elbow fracture-dislocation. Because these injuries may be unrecognized, consideration should be given to diagnosing and addressing them.