Anteromedial Coronoid Fracture Research Articles

Conservative versus surgical management of isolated O'Driscoll II coronoid fracture: A systematic review

PurposeThe purpose of this systematic review is to summarize the current literature on conservative and surgical management of isolated O'Driscoll II coronoid fracture. Study DesignSystematic review. MethodsWe systematically searched Medline, Embase, Google Scholar, and Web of Science databases for published studies by complying with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines and using the keywords “isolated coronoid fracture,” “O'Driscoll type 2 coronoid fracture,” “anteromedial coronoid fracture,” “anteromedial facet coronoid fracture,” “posteromedial rotatory instability,” and “varus posteromedial rotatory instability.” Patients were divided into conservative treatment and surgical treatment groups. Oxford Centre for Evidence-Based Medicine and Methodological Index for Non-Randomized Studies were assessed to determine each article’s quality. The primary outcomes of the present reviews were the Mayo elbow performance score (MEPS) and the disabilities of the arm, shoulder, and hand (DASH) score, and the secondary outcomes were associated with complications and reoperations. Eligible trials were independently chosen by two review authors, and a third reviewer resolved all disagreements. ResultsThe search yielded 458 records, among which 446 articles were of relevance, and 12 were included. In the final review, 138 patients were evaluated—98 (71%) who received surgical treatment and 40 (29%) who received conservative treatment. The mean MEPS score and the DASH score of surgical treatment were 91 and 8, respectively; 69.8% of patients had excellent scores, and 27.0% had good scores. The mean MEPS score and the DASH score of conservative treatment were 92 and 12, respectively; 70.6% of patients had excellent scores, and 23.5% had good scores. ConclusionsIn select cases, conservative treatment can achieve good results in the treatment of isolated O'Driscoll II coronoid fracture when a stricter indication is followed. However, there is insufficient evidence to recommend the appropriate treatment for a particular fracture subtype, and there is a need for more high-quality randomized controlled trials to determine which treatment is superior.

Comparison of buttress plate and cannulated screw in the treatment of anteromedial coronoid fracture with elbow posteromedial rotatory instability.

The purpose of this study is to compare the effect of buttress plate and cannulated screw in the treatment of anteromedial coronoid fracture with posteromedial rotatory instability (PMRI). We retrospectively evaluated patients who were diagnosed with O'Driscoll type 2 fractures combined with elbow posteromedial rotatory instability and underwent surgery for anteromedial coronoid fracture between August 2014 and March 2019. They were divided into buttress plate (n=16) and cannulated screw (n=11) groups. The elbow range of motion, visual analog scale (VAS), Mayo elbow performance score (MEPS), and disabilities of the arm, shoulder, and hand score (DASH) were used for clinical outcome assessment. There were no significant differences in clinical outcomes. However, the surgical time was significantly shorter in cannulated screw group (85.45±4.156) compared to the buttress plate group (93.81±8.863, P=0.008), and the surgical time was associated with internal fixation (P=0.008). Although there was selection of cases in that small fragments were treated with buttress plate and large fragments with cannulated screw, the buttress plate and cannulated screw have comparable functional outcomes on fixation of the anteromedial coronoid fracture with elbow PMRI. The fixation of the anteromedial coronoid fracture with large fragments using the cannulated screw has a shorter operation time.

Coronoid Fractures and Varus Posteromedial Rotatory Instability

Coronoid fractures are associated with elbow fracture-dislocations. Fractures involving the anteromedial facet of the coronoid often are associated with a posteromedial rotational instability pattern which requires careful management to avoid persistent and often subtle instability. Although some anteromedial coronoid fractures may be treated nonoperatively, internal fixation through a medial approach is indicated in most cases. Without a universally accepted treatment algorithm, surgeons should consider the risk of persistent instability when approaching this injury pattern. Fracture morphology, fragment size, and joint congruity, as determined by CT imaging and physical examination, inform clinical decision making.

Coronoid fixation and lateral collateral ligament repair in varus posteromedial rotatory instability of the elbow

BackgroundVarus posteromedial rotatory instability is a relatively rare elbow injury, that has been infrequently reported in published literature. We intended to evaluate the outcomes of surgical management of this rare injury with anteromedial coronoid fixation, and, in selected patients, lateral ulnar collateral ligament (LUCL) repair. MethodsBetween 2017 and 2020, we identified 12 patients with anteromedial coronoid fractures, and a varus posteromedial rotatory instability, who underwent surgery for fixation of the coronoid fracture, with or without LCL repair. All the included patients were either O'Driscoll subtype 2-2, or subtype 2–3. All the 12 patients were followed up for a minimum of 24 months, and their functional outcomes assessed using the Mayo Elbow Performance Score (MEPS). ResultsThe mean MEPS recorded in our study was 92.08, and the mean range of elbow flexion achieved was 124.2°. The mean flexion contracture in our patients was 5.83°. Three of our twelve patients (25%) suffered from elbow stiffness even at final follow-up. The results were graded as Excellent in eight, Good in three, and Fair in one patient. ConclusionCoronoid fractures and LUCL disruptions associated with varus posteromedial rotatory instability can be reliably managed by employing a protocol that combines radiographic parameters, as well as intra-operative assessments of stability. While surgical intervention successfully restored stability, there is a learning curve to the management of these injuries and complications are not uncommon, particularly elbow stiffness. Hence, in addition to surgical fixation, emphasis should also be placed on intensive post-operative rehabilitation to improve outcomes.

Anteromedial coronoid fractures: technical description of an extensile surgical approach and outcomes from a small series using this technique

Varus posteromedial rotatory instability is a difficult clinical problem to diagnose and treat. Fixation of the anteromedial coronoid fracture is often necessary to achieve elbow stability. We describe an extensile surgical approach to the anteromedial coronoid. A retrospective review was performed of all patients at our institution who had anteromedial coronoid fracture fixed with this approach between 2012 and2020. Six patients were identified. They all achieved a stable elbow. Four of 6 developed heterotopic ossification and 2/6 required further surgery for this. Only 1 patient had a transient ulnar sensory loss. We describe an approach to the coronoid that allows great visualization of the joint and access to large coronoid fractures. The approach is extensile and does not require extensive dissection or work around the ulnar nerve. Access to fracture and for fixation can be improved by release of the common flexor pronator origin and the medial collateral ligament.

The three-column concept of elbow joint stability and the Wrightington elbow fracture-dislocation classification, emphasizing the role of cross-sectional imaging.

Elbow fracture-dislocation is a complex injury with a combination of osseous and soft tissue disruption. Different classification systems have been used to describe the injury pattern and help guide the management. The article describes the important cross-sectional findings in complex elbow fracture-dislocation injuries based on the relatively new Wrightington classification. This includes the various elements and patterns seen in elbow fracture-dislocations providing a simple and comprehensive system to classify these injuries and help guide the surgical management. The article also describes the three-column concept of elbow joint stability, dividing the elbow joint osseous structures into lateral, middle and medial columns. Detailed radiological assessment of the fractures pattern is vital to understand the mechanism of injury, allowing clinicians to predict the associated capsuloligamentous injury and help guide the management decisions. The Wrightington elbow fracture-dislocation classification categorizes the injuries according to the ulnar coronoid process and radial head fractures. Type A is an anteromedial coronoid fracture. Type B is a bifacet or basal coronoid fracture, with B + indicating associated radial head fracture. Type C is a combined anterolateral facet and radial head or comminuted radial head fractures. Type D is a diaphyseal ulnar fracture, with D + indicating associated radial head fracture.

Management of anteromedial coronoid fractures according to a protocol focused on instability assessment provides good outcomes with infrequent need for coronoid fixation

Anteromedial coronoid fractures (AMCFs) are associated with persistent elbow instability and post-traumatic arthritis if managed incorrectly. It is unclear exactly which AMCFs require surgical intervention and how to make this decision. The aims of this study were to report outcomes of AMCFs managed using a protocol based on reproduction of instability using radiographic and clinical testingand to ascertain a threshold size of AMCF associated with instability. Forty-three AMCFs were studied. Thirty-two patientsformed the primary study group (group A). All were treated using a protocol in which the decision to perform coronoid fixation was based on the presence of radiographic or clinical evidence of instability. Functional outcomes (Oxford Elbow Score), radiographic outcomes, complications, and reoperations were collected, and a receiver operating characteristic curve analysis was performed to assess the optimal coronoid fracture height to recommend coronoid fixation. The results were compared with a historical group of 11 patientswith AMCFs not treated according to the protocol (group B). Of the patients, 23 had an isolated AMCF and 20 had a concurrent radial head injury. Complete nonoperative treatment of the elbow was performed in 16 patients (37%) (11 of 32 [34%] in group A vs. 5 of 11 [45%] in group B, P = .46). In 10 patients (23%), only repair of the lateral collateral ligament was performed (9 in group A and 1 in group B), whereas 8 patients (19%) underwent repair of the lateral collateral ligament and radial head fixation or replacement (6 in group A and 2 in group B). Acute coronoid fixation was performed in 9 patients (21%) (6 in group A and 3 in group B). At a mean follow-up of 20 months (range, 12-56 months), group A showed a significantly better Oxford Elbow Score (42 vs. 31, P = .02), lower complication rate (3 of 32 [9%] vs. 8 of 11 [72%], P < .001), and lower reoperation rate (1 of 32 [3%] vs. 6 of 11 [54%], P < .001) than group B. Persistent instability was found in 6 patients in group B and none in group A. The receiver operating characteristic curve analysis demonstrated 6.5 mm to be the optimal AMCF size for surgery to prevent persistent instability. Patients treated according to a protocol in which preoperative reproduction of instability determined the degree of surgical intervention had good clinical and radiographic outcomes. Our study demonstrated that AMCFs > 6.5 mm are likely to be more unstable and require intervention. If these principles are followed, a specifically defined subset of AMCFs can be treated nonsurgically without adverse outcomes.

Arthroscopic Treatment of Anteromedial Coronoid Fracture: Complete Functional Recovery at One Year Follow Up

Arthroscopic Treatment of Anteromedial Coronoid Fracture: Complete Functional Recovery at One Year Follow Up

Posteromedial rotatory incongruity of the elbow: a computational kinematics study

Our objective was to analyze the effect of different anteromedial coronoid fracture patterns with different combinations of ligamentous repairs. We hypothesized that smaller fractures would be sufficiently treated with ligamentous repair alone but that larger fragments would require a combination of ligament and bony repair versus reconstruction. Two multibody models were created from cadaveric specimens in the ADAMS program. Four different conditions were simulated: (1) no fracture, (2) O'Driscoll anteromedial subtype I (2.5-mm) fracture, (3) subtype II 2.5-mm fracture, and (4) subtype II 5-mm fracture. In each of these conditions, 3 ligament repairs were studied: lateral ulnar collateral ligament (LUCL), posterior bundle of the medial collateral ligament (pMCL), and both LUCL and pMCL. For each condition, kinematics and articular contact areas were calculated. LUCL repair alone increases whereas pMCL repair decreases internal rotation of the ulna relative to all tested posteromedial rotatory instability conditions; their rotational effects are summative when both ligaments are repaired. With a subtype I fracture and both pMCL and LUCL injuries, repairing the LUCL alone corrects angulation whereas rotational stability is satisfactory through the arc from 0° to 90°. In a subtype II 2.5-mm fracture, isolated repair of the LUCL or pMCL is not capable of restoring rotation or angulation. For a subtype II 5-mm fracture, no combination of ligamentous repairs could restore rotation or angulation. This study suggests that LUCL repair alone is sufficient to restore kinematics for small subtype I fractures for an arc avoiding deep flexion; whereas nearly normal kinematics throughout the arc of motion can be achieved if the pMCL is also repaired. Larger anteromedial coronoid fractures should ideally have fragments fixed in addition to ligament repairs.

Surgical treatment for terrible triad injury of the elbow with anteromedial coronoid fracture through a combined surgical approach.

SummaryObjectiveTo report the results of the surgical treatment of terrible triad injury with anteromedial coronoid fracture through a combined surgical approach.MethodsThis retrospective study evaluated data from patients who underwent surgery to repair terrible triad injuries and anteromedial coronoid fractures. Surgical treatment involved radial head repair or replacement, medial and lateral collateral ligament repair, and coronoid fracture fixation through combined approaches. Evaluations were performed using the Mayo Elbow Performance Score (MEPS) and anteroposterior and lateral radiographs of the elbow.ResultsTwenty-two patients (15 males, seven females; mean ± SD age, 47.5 ± 11.4 years) were enrolled in this study. Fracture union and concentric reduction of both the ulnotrochlear and radiocapitellar articulations were achieved in all patients. The mean ± SD follow-up was 31.6 ± 11.9 months. The mean ± SD arc of flexion–extension was 110.3° ± 26.3° and arc of forearm rotation was 139.5° ± 17.1°. The mean ± SD MEPS was 88.1 ± 12.2 points, with results classified as excellent in eight elbows, good in ten, and fair in four. Six patients had radiographic signs of post-traumatic arthritis. Three patients required secondary surgeries.ConclusionCombined surgical approaches can be considered for the treatment of terrible triad injuries in association with anteromedial coronoid fractures.

Research progress of posteromedial rotatory instability of the elbow

To summarize the research progress in posteromedial rotatory instability (PMRI) of the elbow joint. The recent researches about the management of PMRI of the elbow joint from the aspects of pathological anatomy, biomechanics, diagnosis, and therapy were analyzed and summarized. The most important factors related to PMRI of the elbow joint are lateral collateral ligament complex (LCLC) lesion, posterior bundle of the medial collateral ligament complex (MCLC) lesion, and anteromedial coronoid fracture. Clinical physical examination include varus and valgus stress test of the elbow joint. X-ray examination, computed tomography, particularly three-dimensional reconstruction, are particularly useful to diagnose the fracture. Also MRI, arthroscopy, and dynamic ultrasound can assistantly evaluate the affiliated injury of the parenchyma. It is important to repair and reconstruct LCLC and MCLC and fix coronoid process fracture for recovering stability of the elbow joint. There are such ways to repair ligament injury as in situ repairation and functional reconstruction, which include direct suturation, borehole repairation, wire anchor repairation, and transplantation repairation etc. The methods for fixation of coronal fracture include screw fixation, plate fixation, unabsorbable suture fixation, and arthroscopy technology. It is crucial that recovering the stability of the elbow joint and early functional exercise for the treatment of PMRI. Individual treatment is favorable to protect soft tissue, reduce surgical complications, and improve the functional recovery and the quality of life.

Surgical treatment for the terrible triad injury of the elbow complicated with fracture of the antero-medial facet of coronoid process

Objective To report the clinical results of surgical treatment of fracture of the antero-medial facet of the coronoid process in terrible triad injury. Methods Of the 59 patients with terrible triad injury of the elbow, 17 were surgically treated for fracture of the anteromedial facet of the coronoid process from July 2010 to July 2014. They were 12 men and 5 women, from 29 to 70 years of age (average, 50 years). By the Mason classification for the radial head fractures, 2 cases were type Ⅰ, 13 type Ⅱ and 2 type Ⅲ; by the O’Driscoll classification for coronoid process fractures, one was type Ⅰ, 14 were type Ⅱ and 2 type Ⅲ. All patients were treated through combined approaches. The lateral Kocher approach was used to fixate or replace the radial head and to repair the lateral ligament complex; the anteromedial approach was used to fixate the coronoid process fracture and to explore and repair the medial collateral ligament if neces-sary. Fracture union, implant loosening, ectopic ossification, regression and articular alignment were assessed on the postoperative X-rays. At final follow-ups, the elbow function was evaluated using Mayo elbow perfor-mance score (MEPS) and Broberg & Morrey grading system for traumatic arthritis. Results The average follow-up duration for the 17 patients was 32 months (range, from 24 to 60 months). Final follow-ups showed that the mean arc of flexion-extension was 97° (from 70° to 120°), the mean extension limitation 23° (from 0° to 40°), the mean arc of forearm rotation 139° (from 90° to 145°), the mean pronation 71° (from 60° to 90°) and the mean supination 67° (from 60° to 85°). The MEPT scores averaged 87 points (from 80 to 100 points), yielding 7 excellent, 8 good and 2 fair cases. By the Broberg & Morrey grading, there were 4 cases of grade 1 and one of grade 2. No evidence of elbow instability, nonunion or implant failure was found. Ec-topic ossification around the elbow happened in 4 cases, transient ulnar nerve palsy was found in one, and the Kirschner wire was removed operatively in 2 because it had loosened after fracture union. Conclusion The treatment of anteromedial coronoid fractures in terrible triad injury should be anatomically reduced through direct exposure and fixated rigidly. Key words: Elbow joint; Fracture fixation, internal; Dislocation

Role of the lateral collateral ligament in posteromedial rotatory instability of the elbow

Posteromedial rotatory instability (PMRI) of the elbow consists of an anteromedial coronoid fracture with lateral collateral ligament (LCL) and posterior bundle of the medial collateral ligament (PMCL) tears. We hypothesized that the LCL tear is required for elbow subluxation/joint incongruity and that an elbow affected by an anteromedial subtype 2 coronoid fracture and a PMCL tear exhibits contact pressures different from both an intact elbow and an elbow affected by PMRI. Six cadaveric elbows were tested under gravity varus stress using a custom-made machine designed to simulate muscle loads and to passively flex the elbow from 0° to 90° and measure joint contact pressures. After testing of the intact specimen (INTACT-elbow), an anteromedial subtype 2 coronoid fracture with a PMCL tear (COR+PMCL-elbow) and a PMRI injury (PMRI-elbow), after adding an LCL tear, were tested. The highest values of mean contact pressure were used for the comparison among the 3 groups. Neither subluxation nor joint incongruity was observed in the COR+PMCL-elbow. The addition of an LCL detachment consistently caused subluxation and joint incongruity. Mean contact pressures were higher in the COR+PMCL-elbow compared with the INTACT-elbow (P < .03) but lower than in the PMRI-elbow (P < .001). The LCL lesion in PMRI is necessary for elbow subluxation and causes marked elevations in contact pressures. Even without subluxation, the COR+PMCL-elbow showed higher contact pressures compared with the INTACT-elbow. Treatment of PMRI should be directed toward prevention of joint incongruity, whether by surgical or nonsurgical means, to prevent high articular contact pressures.

Selected anteromedial coronoid fractures can be treated nonoperatively

Surgical fixation is currently recommended for unstable anteromedial coronoid fractures, but the role of nonoperative management is not well defined. Our purpose was to report the functional and radiographic outcomes of select patients managed nonoperatively. Between 2006 and 2012, 10 patients with anteromedial coronoid fractures underwent nonoperative treatment. Outcomes assessed included elbow range of motion (ROM), stability, strength, radiographs, and 3 functional questionnaires, including the Patient-Rated Elbow Evaluation, Disabilities of Arm, Shoulder and Hand, and Mayo Elbow Performance Index. There were 9 anteromedial subtype 2 coronoid fractures and 1 subtype 3. Mean fragment size was 5 mm, with a mean displacement of 3 mm for the subtype 2 fractures. The subtype 3 fracture was 9 mm in size with 1 mm of maximal gap displacement. At a mean follow-up of 50 months (range, 12-83 months), the average ROM of the affected elbow was 137° ± 8° of flexion, 2° ± 5° of extension, 88° ± 5° of pronation, and 86° ± 10° of supination. The mean Patient-Rated Elbow Evaluation score was 9 ± 13, Mayo Elbow Performance Index score was 94 ± 8, and the Disabilities of Arm, Shoulder and Hand score was 7 ± 9. All patients had bony union without radiographic arthrosis. There were no cases of recurrent instability or delayed surgical intervention. Current indications for nonoperative management, based on the results of this study, include fractures that are small, minimally displaced, and most importantly, demonstrate no evidence of elbow subluxation. The elbow joint must be congruent and demonstrate a stable ROM to a minimum of 30° of extension. For selected anteromedial coronoid fractures, nonoperative management is an option that can lead to good clinical and radiographic outcomes.

Complex elbow instability: surgical management of elbow fracture dislocations.

There are three main patterns of complex elbow instability: posterolateral (terrible triad), varus posteromedial (anteromedial coronoid fracture with lateral collateral ligament complex disruption), and trans-olecranon fracture dislocations.Radial head fractures, in the setting of complex elbow instability, often require internal fixation or arthroplasty; the outcome of radial head replacement is dictated by adequate selection of the head diameter, correct restoration of radial length, and proper alignment and tracking.Small coronoid fractures can be ignored. Larger coronoid fractures, especially those involving the anteromedial facet, require fixation or graft reconstruction, particularly in the presence of incongruity.The lateral collateral ligament complex should be repaired whenever disrupted. Medial collateral ligament disruptions seem to heal reliably without surgical repair provided all other involved structures are addressed.The most common mistakes in the management of trans-olecranon fracture dislocations are suboptimal fixation, lack of fixation of coronoid fragments, and lack of restoration of the natural dorsal angulation of the ulna.Cite this article: Sanchez-Sotelo J, Morrey M. Complex elbow instability. EFORT Open Rev 2016;1:183-190.

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.

Medial Elbow Exposure for Coronoid Fractures

The optimal exposure interval for anteromedial coronoid fractures is unknown. The purpose of this study was to quantitatively compare the osseous and ligamentous exposure of the medial elbow using the flexor carpi ulnaris (FCU)-Splitting and Hotchkiss Over-the-Top approaches. Forty surgical approaches were performed on 20 fresh-frozen cadaveric elbows using a randomized crossover design. Access to key anatomic landmarks [anteromedial facet, coronoid tip, sublime tubercle/anterior bundle of the medial collateral ligament (MCL), posterior bundle of the MCL, and radial head] was assessed. A calibrated digital image was taken from the surgeon's perspective of each approach, and these images were analyzed using a software program, ImageJ (NIH), to calculate the surface area of osseous structures exposed. The average surface area exposed was 3 times greater with the FCU-Splitting approach (13.3 cm) compared with the Hotchkiss Over-the-Top approach (4.4 cm) (P < 0.0001). All key anatomic landmarks were directly visualized with the FCU-Splitting approach in each specimen. Visualization of the sublime tubercle/anterior bundle of the MCL and posterior bundle of the MCL was unobtainable with the Hotchkiss approach in 17 (85%) and 20 (100%) specimens, respectively. There were no statistically significant correlations between exposure and sequence of dissection, specimen age, gender, or laterality. The FCU-Splitting approach provides more extensive exposure of the anteromedial coronoid and proximal ulna and the medial ligamentous structures than the Hotchkiss Over-the-Top approach.

Non surgically managed anteromedial coronoid fractures in posteromedial rotatory instability: three cases with 2 years follow-up

Varus posteromedial rotatory instability refers to one of the complex elbow fracture-dislocation caused by anteromedial coronoid fracture with disruption of lateral collateral ligament (LCL). Recent clinical and biomechanical studies have demonstrated that this unstable complex injury resulted in incongruence of joint, which could lead to early posttraumatic arthritis. With reports of poor result after conservative treatment, surgical treatment including anteromedial fixation and LCL repair has been strongly recommended to achieve stable joint. This case series describes three patients with anteromedial coronoid fracture who were managed conservatively with excellent outcomes. This report suggests that anteromedial coronoid fracture associated with posteromedial rotatory instability might be treated using conservative treatment in selective cases when anteromedial coronoid fracture is minimally displaced and there is no evidence of elbow subluxation.

Partial distal humeral resurfacing of a trochlear defect after elbow fracture-dislocation

Varus posteromedial rotatory instability (VPMRI) is a well-recognized type of elbow instability with an injury pattern distinct from posterolateral rotatory instability. O’Driscoll et al recognized that anteromedial coronoid fractures occur because of a varus and posteromedial rotation force on the forearm. This force causes rupture of the lateral collateral ligament (LCL) from the humeral origin. As the LCL stretches and ultimately ruptures, the medial coronoid process comes into contact with the medial trochlea. This contact can lead to fracture of the coronoid process and/or create a defect in the cartilage or subchondral bone of the trochlea. Though type II anteromedial coronoid fractures occur most commonly in VPMRI injuries, a variation with smaller type I coronoid fractures has been described. Radial head fractures are not commonly associated with VPMRI and the anterior band of the medial ulnar collateral ligament is generally intact unless a complete dislocation has occurred. Unrecognized, VPMRI can lead to rapidly progressive ulnohumeral joint arthritis. This is due to unbalanced force across the ulnohumeral joint combined with the medial articular injury. Because of this tendency, early repair is recommended. Optimal results are thought to occur with fixation of coronoid fractures and LCL ligament repair or support with external fixation. Investigations on elbow dislocation or subluxation with associated intra-articular fracture are uncommon. These injuries are generally complex with a high rate of

The Effect of Anteromedial Facet Fractures of the Coronoid and Lateral Collateral Ligament Injury on Elbow Stability and Kinematics

It is postulated that fractures of the anteromedial facet of the coronoid process and avulsion of the lateral collateral ligament lead to posteromedial subluxation and arthritis of the elbow. It is not clear which injuries require internal fixation and whether repair of the lateral collateral ligament is sufficient. We hypothesized that increasing sizes and subtypes of anteromedial facet fractures cause increasing instability and that isolated lateral collateral ligament repair without fracture fixation would restore elbow stability in the presence of small subtype-I fractures. Ten fresh-frozen cadaveric arms from donors with a mean age of 66.3 years at the time of death were used in this biomechanical study. Passive elbow flexion was performed with the plane of flexion oriented horizontally to achieve varus and valgus gravitational loading. An in vitro unconstrained elbow-motion simulator was used to simulate active elbow flexion in the vertical position. Varus-valgus angle and internal-external rotational kinematics were recorded with use of an electromagnetic tracking system. Testing was repeated with the coronoid intact and with subtype-I, subtype-II, and subtype-III fractures. Instability was defined as an alteration in varus-valgus angle and/or in internal-external rotation of the elbow. All six coronoid states were tested with the lateral collateral ligament detached and after repair. In the vertical position, the kinematics of subtype-I and subtype-II anteromedial coronoid fractures with the lateral collateral ligament repaired were similar to those of the intact elbow. In the varus position, the kinematics of 2.5-mm subtype-I fractures with the lateral collateral ligament repaired were similar to those of the intact elbow. However, 5-mm fractures demonstrated a mean (and standard deviation) of 6.2 degrees +/- 4.5 degrees of internal rotation compared with a mean of 3.3 degrees +/- 3.1 degrees of external rotation in the intact elbow (p < 0.05). In the varus position, subtype-II 2.5-mm fractures with the lateral collateral ligament repaired demonstrated increased internal rotation (mean, 7.0 degrees +/- 4.5 degrees; p < 0.005). Subtype-II 5-mm fractures demonstrated instability in both the varus and valgus positions (p < 0.05). Subtype-III fractures with the lateral collateral ligament repaired were unstable in all three testing positions (p < 0.05). This study suggests that the size of the anteromedial coronoid fracture fragment affects elbow kinematics, particularly in varus stress. The size of an anteromedial coronoid fracture and the presence of concomitant ligament injuries may be important determinants of the need for open reduction and internal fixation.