Selected anteromedial coronoid fractures can be treated nonoperatively

Medial elbow approaches for coronoid fractures: risk to the ulnar nerve

Background

Coronoid fractures often require open reduction internal fixation (ORIF) to restore elbow stability. The flexor pronator split, flexor carpi ulnaris (FCU) split, and Taylor and Scham (T&S) approaches are frequently used medial approaches to access the coronoid. The ulnar nerve can be released or transposed when performing these exposures. The optimal medial surgical approach and management of the ulnar nerve has not been clearly defined. The purpose of this study was to compare postoperative ulnar nerve complications in coronoid fractures undergoing ORIF following a medial surgical approach and ulnar nerve release or transposition.

Methods

A retrospective review of 91 patients with coronoid fractures treated with ORIF using a medial approach from 2004 to 2022 was performed at three academic medical centers. Patients ≥ 18 years of age who sustained coronoid fractures with or without associated injuries were included. Patient charts and perioperative imaging were reviewed. Patient demographics, fracture classification, associated injuries, surgical approaches, ulnar nerve management, and postoperative complications were recorded. Primary outcomes assessed were signs and symptoms of postoperative ulnar nerve neuropathy.

Results

The mean age of the cohort was 45 ± 16 years, 71% were males, with a mean length of follow-up of 16 ± 22 months. Of the 91 coronoid fractures, 69 were anteromedials, eight were tips, and 14 were basal types. The incidence of preoperative ulnar neuropathy was 5% (n = 5). The incidence of postoperative ulnar neuropathy was 33% (n = 30) of which 55% (n = 16) completely resolved by final follow-up. The rate of postoperative ulnar neuropathy was not significantly different between in situ release 30% (n = 9) or transposition of the ulnar nerve 34% (n = 20), (P = .64). There was a significantly higher rate of postoperative resolution with transposition (70%) versus in situ release (22%), (P = .045). The rate of postoperative ulnar neuropathy was not significantly different between the FCU, T&S, or flexor pronator split approaches, (P = .331). Finally, the rate of neuropathy resolution was not significantly different between medial approaches (P = .46).

Conclusion

There was no statistical difference in the incidence of postoperative ulnar nerve complications with ulnar nerve transposition or in situ release following coronoid fixation. However, transposing the nerve resulted in a higher rate of neuropathy resolution. While the incidence of postoperative ulnar nerve dysfunction is high following coronoid fixation when using a medial surgical approach, it was similar with the FCU, T&S, and flexor pronator split approaches. Larger cohorts and randomized clinical trials are needed to confirm these findings.

Role of three-dimensional computed tomography with humeral subtraction in assessing anteromedial facet coronoid fractures

Background

The anteromedial facet (AMF) of the coronoid is a key structure in resisting varus posteromedial rotatory instability (PMRI) of the elbow. However, not all isolated coronoid fractures involve the AMF and not all fractures involving the AMF are the result of a PMRI mechanism. There is debate regarding the management of isolated coronoid fractures. A reliable method of differentiating this heterogeneous group of isolated coronoid fractures is essential to develop an appropriate management algorithm. The aim of this study was to evaluate the role of additional humeral subtraction three-dimensional (3D) images in the detailed assessment of the known radiographic features of AMF fractures with PMRI mechanism.

Methods

Three upper extremity fellowship-trained orthopedic surgeons evaluated 32 consecutive CT scans in patients with isolated coronoid fractures, on two occasions separated by at least 5 months. On each occasion, CT scan images were evaluated for fracture morphology and orientation in two rounds. In the first round, the evaluation was made based on all two-dimensional and 3D reconstruction images of the entire elbow; in the second round, the surgeons had access to images from the first round plus 3D reconstruction with humeral subtraction. Statistical analysis to assess agreement amongst the surgeons was performed using the kappa multirater analysis. Intraobserver agreement was evaluated using Pearson's correlation coefficient.

Results

The addition of the humeral subtraction view significantly improved the interobserver agreement for fracture morphology from 0.28 (95% confidence interval [CI] 0.07-0.49) to 0.66 (95% CI 0.46-0.87), P < .001; and for orientation from 0.31 (95% CI 0.09-0.52) to 0.54 (95% CI 0.31-0.77), P < .001. Similarly, the intraobserver Pearson correlation improved from 0.28-0.38 to 0.48-0.76 for fracture morphology, and from 0.36-0.77 to 0.51-0.69 for fracture orientation.

Conclusion

3D CT reconstruction with humeral subtraction improved surgeons' ability to characterize radiographic features of AMF coronoid fractures. Future studies are required to determine whether better characterization of the morphology and orientation of AMF fractures allows for the categorization of these fractures into more homogenous groups and the development of more consistent management algorithms.

Outcomes and complications after treatment for anteromedial facet fracture of the coronoid process: A systematic review

BACKGROUND

Fracture of the anteromedial facet (AMF) of the coronoid process is associated with varus posteromedial rotatory instability (VPMRI). However, there is still controversy regarding the optimal treatment for AMF fracture. The purpose of this study is to report on a systematic review of the outcomes and complications after treatment for AMF fracture.

METHODS

This study was conducted using electronic databases, PubMed, EMBASE and Scopus. Studies reporting outcome scores and complications were included. Studies that did not utilize O'Driscoll classification for AMF fractures were excluded. Through conduct of a thorough review of included studies, definite VPMRI were identified and cases involving other injury mechanisms were excluded.

RESULTS

Fifteen articles reporting on 246 patients were included. According to O'Driscoll classification, 6.2% of cases were anteromedial subtype I, 73.7% were subtype II, and 20.1% were subtype III. Two-hundred sixteen patients (87.8%) were treated surgically and 30 patients (12.2%) were treated conservatively. Lateral collateral ligament (LCL) injuries were 76.2% (157/206) and medial collateral ligament injuries were 16.9% (33/195). Among 216 cases who underwent surgical treatment, depending on the fragment size, displacement, and instability, coronoid fixation was performed in 189 cases and LCL repair alone was performed in 27 cases. The mean final Mayo Elbow Performance Score was 92.1 and the Broberg & Morrey score was 89.5. The overall complication and reoperation rates were 17.7% (41/232) and 12.9% (26/202).

CONCLUSIONS

Both surgical and conservative treatment for AMF fractures resulted in satisfactory final clinical outcomes. However, high complication and reoperation rates were observed.

Factors associated with the choice of treatment for coronoid fractures

Aims

This study aimed to gather insights from elbow experts using the Delphi method to evaluate the influence of patient characteristics and fracture morphology on the choice between operative and nonoperative treatment for coronoid fractures.

Methods

A three-round electronic (e-)modified Delphi survey study was performed between March and December 2023. A total of 55 elbow surgeons from Asia, Australia, Europe, and North America participated, with 48 completing all questionnaires (87%). The panellists evaluated the factors identified as important in literature for treatment decision-making, using a Likert scale ranging from "strongly influences me to recommend nonoperative treatment" (1) to "strongly influences me to recommend operative treatment" (5). Factors achieving Likert scores ≤ 2.0 or ≥ 4.0 were deemed influential for treatment recommendation. Stable consensus is defined as an agreement of ≥ 80% in the second and third rounds.

Results

Of 68 factors considered important in the literature for treatment choice for coronoid fractures, 18 achieved a stable consensus to be influential. Influential factors with stable consensus that advocate for operative treatment were being a professional athlete, playing overhead sports, a history of subjective dislocation or subluxation during trauma, open fracture, crepitation with range of movement, > 2 mm opening during varus stress on radiological imaging, and having an anteromedial facet or basal coronoid fracture (O'Driscoll type 2 or 3). An anterolateral coronoid tip fracture ≤ 2 mm was the only influential factor with a stable consensus that advocates for nonoperative treatment. Most disagreement existed regarding the treatment for the terrible triad injury with an anterolateral coronoid tip fracture fragment ≤ 2 mm (O'Driscoll type 1 subtype 1).

Conclusion

This study gives insights into areas of consensus among surveyed elbow surgeons in choosing between operative and nonoperative management of coronoid fractures. These findings should be used in conjunction with previous patient cohort studies when discussing treatment options with patients.

Pure varus posteromedial rotatory instability of the elbow: Radiographic findings, treatment, and outcomes

INTRODUCTION

Although varus posteromedial rotatory instability (VPMRI) is a subtle elbow injury that involves anteromedial coronoid facet (AMCF) fracture and ligamentous injuries, treatment options and outcomes of VPMRI remains controversial. The aim of this study was to investigate radiographic findings, treatments, and outcomes of a large series of VPMRI.

METHODS

We retrospectively reviewed 91 pure VPMRI cases with AMCF fracture (O'Driscoll classification anteromedial type) which were treated at 6 hospitals. Clinical and radiographic outcomes were investigated with a mean follow-up period of 46.8 months using the Mayo elbow performance score (MEPS), and the Quick Disabilities of the Arm, Shoulder and Hand (Quick-DASH) score, and serial plain radiographs.

RESULTS

In AMCF fracture, there were 4 cases of subtype 1, 67 cases of subtype 2, and 20 cases of subtype 3. On MRI, complete tears of lateral collateral ligament and medial collateral ligament were observed in 83.1 % (59/71 cases) and 33.8 % (24/71 cases). Operative treatment was performed in 68 cases (74.7 %) including both side fixation in 40 cases (58.8 %), medial side fixation only in 17 cases (25.0 %), and lateral side fixation only in 11 cases (16.2 %). Nonoperative treatment was performed in 23 cases (25.3 %). The mean final MEPS and Quick-DASH scores were 93.7 and 7.9. The overall complication and reoperation rates were 22.0 % and 15.4 %. No significant differences regarding final clinical scores and range of motions were observed between the operative group and the nonoperative group, but significant differences were observed regarding number (p = 0.019) and displacement (p = 0.002) of coronoid fragment, and complication rate (p < 0.001) between the two groups.

CONCLUSION

Depending on the pattern of coronoid fragment and the degree of ligamentous injuries, operative treatment of unstable VPMRI using various fixation techniques including coronoid fixation and ligament repair yielded satisfactory final clinical outcomes. However, surgeons should be aware of the high complication and reoperation rates after operative treatment. Stable VPMRI with AMCF fracture involving minimal displacement or small number of fragments can be treated nonoperatively.

A Feasibility Study on Using Hanging Arm Test to Assess Elbow Stability During Surgical Treatment for Varus Posteromedial Rotatory Instability

Objectives

The aim of this study to investigate the safety and effectiveness of performing the hanging arm test during surgical treatment for elbow varus posteromedial rotatory instability (VPMRI) to assess elbow stability and determine whether to repair the lateral ulnar collateral ligament (LUCL).

Methods

In a retrospective study from August 2014 to March 2019, 27 patients with VPMRI who had a negative result in the hanging arm test after fixation of coronoid fracture were selected. Intraoperative bleeding, operative time, elbow range of motion (ROM), and complications were recorded. Elbow function was evaluated with the Mayo elbow performance score (MEPS) and the disabilities of the arm, shoulder, and hand (DASH) score.

Results

The operation time was 85.9 ± 11.06 min (range 65-110). The intraoperative blood loss was 70.7 ± 9.31 ml (range 60-100). At the last follow-up, the elbow joint averaged 73.8° ± 2.931° in pronation, 78.9° ± 2.941° in supination, 7.2° ± 3.207° in extension, and 123.3° ± 6.651° in flexion. The MEPS score was 90.7 ± 4.36 (range 74-95), and the DASH score was 9.8 ± 2.58 (range 6.67-13.3). One patient presented with symptoms of ulnar nerve entrapment 2 months after operation and was treated with ulnar nerve release. The symptom of numbness went away completely 1 week after operation. No complications such as wound infection, arthritis, or chronic instability of the elbow were found in the other patients.

Conclusion

Our findings suggest that not all VPMRI patients need the LUCL to be repaired, and the hanging arm test is a safe and reliable method to assess whether to repair the LUCL in the treatment of elbow VPMRI.

Level of evidence

Level IV; Retrospective studies.

Finite element analysis of a customized coronoid prosthesis for traumatic coronoid deficiency

BACKGROUND

Traumatic coronoid deficiency with persistent elbow instability is a challenging condition. Autologous bone graft reconstruction is often associated with a range of additional clinical problems and the outcome is often unpredictable. The purpose of this study was to design a prosthetic device that can reconstruct coronoid deficiency of any height and to evaluate its mechanical properties using finite element analysis.

MATERIALS AND METHODS

A customized coronoid prosthesis was designed based on image registration, automatic measurement, and computer-aided design. After pilot study and sample size calculation, image data collected from 6 patients who underwent bilateral complete upper extremity CT scans were reconstructed. The test was divided into 3 groups: coronoid intact, prosthesis and autograft. Regan-Morrey type II and autologous olecranon osteotomy models were established. The prosthesis and autogenous olecranon were assembled to the coronoid base. Stress was applied axially along the proximal humeral diaphysis and implant micromotion and contact mechanics of the humeroulnar joint were measured at 30°, 45°, 60° and 90° of joint flexion respectively.

RESULTS

At all flexion angles, the maximum stress on the coronoid articular surface was significantly reduced in the prosthesis and autograft groups, with the reduction being more significant in the latter (P < .001). With increasing flexion, the maximum stress at the coronoid articular surface increased significantly after autograft reconstruction (7.2 to 68 MPa, P < .001), whereas the humeroulnar joint obtained a similar contact mechanics pattern to that of the control group after prosthetic reconstruction. As the flexion angle increased, the relative micromotion of both the prosthesis and autograft increased significantly (0.5-1.6 vs. 0.2-1.2, Pmeasure time < 0.001, Pgroups < 0.001). Contact pressure and center-of-force paths of the humeroulnar joint experience abrupt stress changes at approximately 60° of flexion.

CONCLUSION

The contact stress pattern in the humeroulnar joint is similar in prosthesis and intact coronoid groups. Autograft reconstruction increases contact stresses at the articular surface and alters the joint center-of-force path. The "stress surge phenomenon" in the humeroulnar joint surface before and after 60° of flexion may be one of the mechanisms of traumatic elbow degeneration.

Morphometrics of the coronoid process and the radial notch of the ulna: implications for fracture assessment

PURPOSE

A comprehensive analysis of the morphology of fractures of the coronoid process (CP) can aid diagnosis and guide treatment. The involvement of the radial notch of the ulna (RN)-e.g., in anterolateral facet fractures and transverse fractures of the CP-may influence the biomechanical conditions of the proximal radioulnar joint. However, the morphometric relation between the CP and the RN and the extent to what the proximal radioulnar joint can be affected in these types of fractures is unknown.

METHODS

A total of 113 embalmed, cadaveric ulnae were dissected. All soft tissue was removed. Strictly lateral, high-resolution photographs were taken and digitally analyzed. The height of the CP and its relation to the RN was measured. Sex differences and correlations between measured parameters were calculated.

RESULTS

Mean height of the CP was 16 mm (range: 12-23 mm; SD: 2). Mean height of the RN was 16 mm (11-25 mm; 2.2). The 50% mark of the CP corresponded to 18% (0-56%; 11.2) of the height of the RN. No significant differences were found between male and female specimens.

CONCLUSION

The RN of the ulna extends only to a small part to the CP. Transverse or anterolateral fractures of less than 50% of the coronoid process may involve only a small portion of the proximal radioulnar joint.

"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.

Coronoid fractures and traumatic elbow instability

The coronoid process is key to concentric elbow alignment. Malalignment can contribute to post-traumatic osteoarthritis. The aim of treatment is to keep the joint aligned while the collateral ligaments and fractures heal. The injury pattern is apparent in the shape and size of the coronoid fracture fragments: (1) coronoid tip fractures associated with terrible triad (TT) injuries; (2) anteromedial facet fractures with posteromedial varus rotational type injuries; and (3) large coronoid base fractures with anterior (trans-) or posterior olecranon fracture dislocations. Each injury pattern is associated with specific ligamentous injuries and fracture characteristics useful in planning treatment. The tip fractures associated with TT injuries are repaired with suture fixation or screw fixation in addition to repair or replacement of the radial head fracture and reattachment of the lateral collateral ligament origin. Anteromedial facet fractures are usually repaired with a medial buttress plate. If the elbow is concentrically located on computed tomography and the patient can avoid varus stress for a month, TT and anteromedial facet injuries can be treated nonoperatively. Base fractures are associated with olecranon fractures and can usually be fixed with screws through the posterior plate or with an additional medial plate. If the surgery makes elbow subluxation or dislocation unlikely, and the fracture fixation is secure, elbow motion and stretching can commence within a week when the patient is comfortable.

Evaluation of Surgical Approaches to Management of Traumatic Posteromedial Elbow Instability Syndrome: A Systematic Literature Review Protocol

Posteromedial Instability Syndrome of the Elbow (PMIE) is a condition that arises from injuries to the stabilizing structures of the elbow joint, such as the coronoid process or ulnar lateral collateral ligament. Surgical treatment is commonly performed, but there is uncertainty regarding its results. This systematic review will synthesise the available evidence regarding the efficacy of surgical approaches to PMIE. Published and unpublished primary studies that regard outcomes of patients treated for PMIE, irrespective of approach, will be considered for inclusion. Iterative searches will be performed in the PubMed/MEDLINE, EMBASE, and Cochrane CENTRAL repositories from their inception to May 2023. Grey literature repositories will also be searched. The Cochrane risk of bias tool will be used to assess the quality of eligible interventional studies, while the MINORS tool will be employed for observational studies. If possible, a meta-analysis based on the random-effects model will be conducted. Heterogeneity will be assessed using Cochrane's Q and I2 statistics, and explored through subgroup analyses and sensitivity analyses. Relevant outcomes will include elbow joint functionality as assessed by validated scales, the proportion of patients returning to usual daily life activities, the development of recurrent joint instability in the postoperative period, quality of life and the development of postoperative arthritis. This protocol has been registered in the International Prospective Register of Systematic Reviews (PROSPERO) at the University of York. Its registration number is CRD42023451516.

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

PURPOSE

The purpose of this systematic review is to summarize the current literature on conservative and surgical management of isolated O'Driscoll II coronoid fracture.

STUDY DESIGN

Systematic review.

METHODS

We 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.

RESULTS

The 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.

CONCLUSIONS

In 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

PURPOSE

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).

METHODS

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.

RESULT

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).

CONCLUSION

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.

Anteromedial coronoid facet fractures and associated ligament lesions: A case series

INTRODUCTION

Varus posteromedial rotational injury mechanisms lead to fractures of the coronoids process' anteromedial facet. As these fractures are often unstable, rapid fracture treatment is vital to prevent progressive osteoarthritis.

MATERIALS AND METHODS

Twelve patients with a fracture of the anteromedial facet treated surgically were enrolled in the study. Computed tomography images were used to classify the fractures according to the system by O'Driscoll et al. Clinical follow-up included each patient's medical record, surgical treatment algorithm, all complications encountered during the follow-up period, Disabilities of the arm, shoulder, and hand score, subjective elbow value, and pain.

RESULTS

A total of 8 men (66.7%) and 4 women (33.3%) were treated surgically and followed-up after a mean period of 45 ± 23 months. The mean DASH score was 11.9 ± 12.9 points. One patient complained of transient neuropathy in the innervation area of the ulnar nerve, however, this existed already pre-operatively and resolved after less than three months.

CONCLUSIONS

The presented patient cohort shows that AMF fracture of the coronoid process are unstable lesions according to the bony instability and the frequently ruptured collateral ligament complexes which need to be addressed. The MCL seems to be affected more frequently than previously appreciated.

LEVEL OF EVIDENCE

Level IV; Case Series; Treatment Study.

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

Background

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.

Methods

A retrospective review was performed of all patients at our institution who had anteromedial coronoid fracture fixed with this approach between 2012 and 2020.

Results

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.

Conclusion

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.

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

Background

Varus 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.

Methods

Between 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).

Results

The 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.

Conclusion

Coronoid 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.

Results of arthroscopically assisted reduction and fixation of anteromedial facet coronoid fractures at short-term follow-up

BACKGROUND

Varus posteromedial rotatory instability is a typical pattern of elbow injury that involves fracture of the anteromedial facet (AMF) of the coronoid, as well as injuries to the lateral ligament complex and the posterior bundle of the medial collateral ligament. Some authors support the idea that subtype II AMF coronoid fractures require fixation to restore elbow stability, but this topic is still an issue in the literature. The purpose of this study was to assess the clinical and radiologic outcomes of arthroscopically assisted reduction and internal fixation (ARIF) of AMF fractures.

METHODS

This retrospective single-center trial evaluated consecutive patients who underwent ARIF of isolated subtype II AMF coronoid fractures between 2014 and 2020. At the final follow-up, the patients were examined for elbow range of motion, stability, and pain. Injury and post-treatment radiographs were reviewed to assess fracture healing and heterotopic ossification.

RESULTS

A total of 32 patients (21 male and 11 female patients) with a median age of 47 ± 16 years were included. The average follow-up period was 28 ± 12.4 months. Coronoid process fractures were fixed by cannulated screws in 26 cases (81.25%); in 2 of these cases, additional Kirschner wires were used. Two Kirschner wires were used in 1 case (3.12%), and in the remaining 5 cases (15.62%), osteosuture was used. The lateral ulnar collateral ligament was injured in 27 cases (84.4%) and was always repaired. Other associated lesions were medial collateral ligament injury, osteochondral lesion, and radial head fracture. There were no surgical complications. At the final follow-up, the average Mayo Elbow Performance Score was 98.4 ± 2.7 and the mean Oxford Elbow Score was 47.3 ± 1.4. No cases of nonunion were detected on radiographic assessment.

CONCLUSIONS

Although technically demanding, ARIF has several potential advantages in comparison to open surgery: less scarring, a decreased risk of infection, and less postoperative pain.

Classification of coronoid process fractures: A pending question

Ulna coronoid fracture is a complicated elbow injury. Comprehensive classification of coronoid fracture can assist diagnosis, guide treatment, and improve prognosis. Existing coronoid fracture classifications are insufficient to interpret all fracture patterns. The coronoid fracture classification is associated with elbow-specific trauma patterns. Coronoid fractures are often associated with other elbow injuries, commonly with radial head fractures, which makes the clinical strategies inconsistent and prognosis poor. The current fracture classifications do not contain information about combined injuries. Preservation of ulnohumeral joint contact after trauma is critical to elbow mechanical and kinematic stability. Important fracture types for treatment include terrible-triad injuries and anteromedial facet fractures. Open reduction and internal fixation of these two fractures should be conducted when marked displacement of the fragment, elbow instability under stress, and complicated associated injuries. The current surgical tactics based on classifications are still controversial.

The radiological findings in complex elbow fracture-dislocation injuries

Elbow fracture-dislocation is a complex injury which can lead to significant bony and soft tissue damage. Surgical intervention is guided towards restoring joint stability, allowing early mobilization and preventing long-term joint stiffness. The most common types are posterolateral, posteromedial, Monteggia type (and variants), and anterior trans-olecranon fracture-dislocations. Posterolateral fracture-dislocation is characterized by a radial head fracture (± anterolateral coronoid fracture) and typically capsuloligamentous disruption (lateral collateral ligaments injury is the most common). A posterolateral fracture-dislocation with radial head and coronoid anterolateral facet fractures is termed a terrible triad injury. In posteromedial fracture-dislocation, there is a fracture of the anteromedial facet of the coronoid, typically with proximal avulsion of the lateral collateral ligaments (± injury to the posterior bundle of the ulnar collateral ligament). Monteggia fracture-dislocation injuries demonstrate proximal ulnar fracture (with possible involvement of the olecranon and the coronoid) and radial head dislocation. These can be divided into apex anterior or apex posterior variants. The latter are commonly associated with radial head fractures and lateral ligamentous injury, and have a worse prognosis. In trans-olecranon fracture-dislocation, there is significant disruption of the greater sigmoid notch and the olecranon, with various involvement of the coronoid and the proximal ulna. The article describes the radiological findings and outlines the management principles in complex elbow fracture-dislocation injuries.

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.

Morphological characteristics of fractures of the anteromedial facet of the coronoid in posteromedial rotatory instability of the elbow: a three-dimensional CT remodeling study

BACKGROUND

Fractures of the anteromedial facet of the coronoid in posteromedial rotatory instability of the elbow are classified into 3 subtypes based on their location. The purpose of this study was to analyze the fracture morphology of anteromedial facet fractures in their 3 subtypes (anteromedial rim, anteromedial rim + tip, and anteromedial rim + sublime tubercle [±tip]).

METHODS

Three-dimensional computed tomography remodeling was used to evaluate anteromedial facet fractures in a consecutive series of 40 patients, all of whom were affected by posteromedial rotatory instability of the elbow. Characteristics of the fractures, including the number of fragments, size of fragments, plane of the fracture line, and involvement of the sublime tubercle and radial notch, were measured for each subtype of the anteromedial facet fractures.

RESULTS

Each subtype had a typical fracture pattern and distinct size. The fracture subtype 1 showed a single-fragment fracture, subtype 2 showed either a single- or dual-fragment fracture, and subtype 3 showed either a dual- or triple-fragment fracture. The angle between the fracture line and the coronal plane was greatest in subtype 3 fractures. The surface area of the fragment was largest in subtype 3 fractures. The percentages of articular involvement of the sublime tubercle were 0% in subtype 1, 47% in subtype 2, and 79% in subtype 3. The percentages of articular involvement of the radial notch were 0% in subtype 1, 7% in subtype 2, and 8% in subtype 3.

CONCLUSION

Analysis with quantitative 3-dimensional computed tomography showed the characteristic morphology of each subtype of anteromedial facet fracture. Subtype 1 comprised 1 fragment with the smallest fragment size. Subtype 2 was a single- or dual-fragment fracture, the size of which should be considered in the treatment plan. Subtype 3 was a large fragment comprising the sublime tubercle. Our findings are significant because they highlight unique fracture morphology that may help surgeons to distinguish one fracture subtype from another in clinical practice.

Proximal ulna fractures in adults: A review of diagnosis and management

Proximal ulna fractures are relatively common upper limb injuries, which may represent fragility fractures or result from high-energy trauma. These include fractures of the olecranon, coronoid and associated radial head dislocations. A wide variety of treatment options are available for the management of these injuries that makes the selection of most appropriate treatment difficult. We aim to provide a brief overview of the treatment options for such injuries.

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.

Coronoid process reconstruction with a distal clavicle autograft: an in silico analysis of fitting accuracy

BACKGROUND

The coronoid process plays a vital role in preserving elbow stability. In cases of acute or chronic deficiency of the coronoid process, reconstruction is warranted to restore stability and to avoid early joint degeneration. The distal clavicle might be a useful osteochondral autograft for coronoid reconstruction with low donor-site morbidity. This study evaluated the fitting accuracy of the distal clavicle as an autograft for coronoid process reconstruction.

METHODS

One hundred upper-extremity computed tomography scans of 85 body donors were available for this study (mean age, 69 ± 17 years; 46 male and 39 female donors; 15 bilateral specimens). Standardized 40% transverse defects of the coronoid process were digitally created; the distal clavicles were digitally harvested and placed onto the defects by a best-fit technique in 2 different orientations using commercially available software: (1) with the superior aspect of the articular surface of the graft oriented toward the coronoid tip and (2) with the inferior aspect of the articular surface of the graft oriented toward the coronoid tip. The fitting accuracy of the grafts to the native coronoid process was evaluated from lateral to medial using custom code.

RESULTS

Regardless of the orientation of the graft, the distal clavicle provided a good fit in the central portion of the coronoid process. In the lateral and medial aspects of the defect, however, the fitting accuracy of the graft declined significantly (P ≤ .044). No significant differences were observed between ipsilateral and contralateral grafts (P ≥ .199). The intrarater reliability was excellent.

CONCLUSION

The results of this study suggest that a distal clavicle autograft may be suitable to replace a transverse defect of the coronoid process; however, it may not fully reconstruct the anteromedial and anterolateral aspects of the coronoid.

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

BACKGROUND

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 testing and to ascertain a threshold size of AMCF associated with instability.

METHODS

Forty-three AMCFs were studied. Thirty-two patients formed 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 patients with AMCFs not treated according to the protocol (group B).

RESULTS

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.

CONCLUSION

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.

The treatment of anteromedial coronoid facet fractures: a systematic review

BACKGROUND

Fractures of the anteromedial facet (AMF) of the coronoid process are caused by a varus posteromedial rotational injury force, leading to instability in the ulnohumeral joint. AMF fractures are usually accompanied by avulsion of the lateral ulnar collateral ligament (LUCL). O'Driscoll's description and classification of AMF coronoid fractures has increased awareness and interest in this injury, but the optimal treatment has yet to be decided.

METHODS

We systematically reviewed the available literature searching electronic databases, MEDLINE using the PubMed interface and Embase. The primary objective was to determine outcome scores but also complication and revision rates depending on the fracture and its therapy in order to gain a more comprehensive picture. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines were applied.

RESULTS

Initially, 304 publications were identified. Finally, 10 studies were left for inclusion, all of them retrospective in design, comprising 128 patients; the majority of them were male (75.7%). A total of 114 patients (89.1%) were treated surgically and 14 patients (10.9%) were treated conservatively. Among the surgically treated patients, 70.2% were treated with LUCL refixation. The average Mayo Elbow Performance Score of the surgically treated patients was 91.5 points. The average Mayo Elbow Performance Score of the conservatively treated patients was 91.4 points. A total of 10 patients (7.8%) required reoperation.

CONCLUSION

Surgery of AMF fractures leads to a satisfactory functional outcome in the vast majority of patients independent of the subtype. An algorithm for LUCL fixation is still pending. Conservative treatment may be considered under strict preconditions, especially for nondisplaced subtype 1 and 2 fractures, as these fractures show satisfactory functional outcomes when treated nonoperatively.

Biomechanical comparison of screw osteosyntheses and anatomical plating for coronoid shear fractures of the ulna

INTRODUCTION

Among the few techniques described for the treatment of coronoid fractures, osteosynthesis techniques include screw osteosynthesis from anterior to posterior (AP) or from posterior to anterior (PA) and plate osteosynthesis. The aim of this study was to test the biomechanical stability of screw osteosynthesis and plate osteosynthesis using anatomical plates in coronoid process fractures.

MATERIALS AND METHODS

On a total of 25 biomechanical synthetical ulnae, a coronoid shear fracture including 70% of the coronoid height was simulated. Osteosynthesis was then performed using two 2.7 mm screws from anterior, posterior and with use of three different anatomical plates of the coronoid process. For the biomechanical testing, axial load was applied to the fragment with 1000 cycles from 5 to 250 N, load to failure and load at 100 µm displacement. Displacements were measured using a point-based three-dimensional motion analysis system.

RESULTS

Osteosynthesis using the PA-screw showed significant more displacement during cyclic loading compared with all other osteosyntheses (0.99 mm), whereas AP-screw showed the smallest displacement (0.10 mm) during cyclic loading. The PA-screw technique showed a significant lower load to failure compared to all other osteosynthesis with the highest load in AP-screw osteosynthesis. The load for 100 µm displacement was the smallest in PA-screw with a significant difference to the AP-screw and one plate osteosynthesis.

CONCLUSION

Osteosynthesis of large coronoid shear fractures with two small-fragment screws from anterior allows stable fixation that is not inferior to anterior plate osteosynthesis and might be an alternative in specific fracture types. Posterior screw fixation was found as the weakest fixation method.

LEVEL OF EVIDENCE

Basic science study.

Injuries to the Coronoid Process of the Ulna with Involvement of the Lesser Sigmoid Notch

INTRODUCTION

This study aimed to describe the involvement of the lesser sigmoid notch in fractures to the coronoid process. We hypothesized that injuries to the lateral aspect of the coronoid process regularly involve the annular ligament insertion at the anterior lesser sigmoid notch.

MATERIAL AND METHODS

Patients treated for a coronoid process fracture at our institution between 06/2011 and 07/2018 were included. We excluded patients < 18 years, patients with arthritic changes or previous operative treatment to the elbow, and patients with concomitant injuries to the proximal ulna. In patients with involvement of the lesser sigmoid notch, the coronoid height and fragment size (anteroposterior, mediolateral, and craniocaudal) were measured.

RESULTS

Seventy-two patients (mean age: 47 years ± 17.6) could be included in the study. Twenty-one patients (29.2%) had a fracture involving the lateral sigmoid notch. The mean anteroposterior fragment length was 7 ± 1.6 mm. The fragment affected a mean of 43 ± 10.8% of the coronoid height. The mean mediolateral size of the fragment was 10 ± 5.0 mm, and the mean cranio-caudal size was 7 ± 2.7 mm.

CONCLUSION

Coronoid fractures regularly include the lesser sigmoid notch. These injuries possibly affect the anterior annular ligament insertion which is important for the stability of the proximal radioulnar joint and varus stability of the elbow.

[Plate osteosynthesis of the coronoid process of the ulna]

OBJECTIVE

The aim of surgical treatment is reconstruction of the coronoid process' bony anatomy.

INDICATIONS

Large shear fractures of the coronoid process (Regan-Morrey type II-III, O'Driscoll "tip" subtype 2 and "basal" subtype 1-2) and fractures of the anteromedial facet (O'Driscoll "anteromedial" subtype 1-3) can occur isolated or as part of the "terrible triad" injuries to the elbow. Due to the resulting instability of these injuries, surgical reconstruction is generally indicated.

CONTRAINDICATIONS

In case of major accompanying soft tissue injuries to the elbow or an elbow infection, primary operative treatment using anatomical plate osteosynthesis is contraindicated.

SURGICAL TECHNIQUE

Plate osteosynthesis of the coronoid process is performed through a medial approach (Hotchkiss or M. flexor carpi ulnaris split). After repositioning of the fracture fragments, a preformed anatomical plate can be fixed to the coronoid process.

POSTOPERATIVE MANAGEMENT

The arm is immobilized in an over-the-elbow cast until the wounds are dried. Afterwards, the elbow should preferably be treated functionally without varus or valgus stress.

RESULTS

Between January 2015 and July 2018, a total of 11 patients underwent osteosynthesis of the coronoid using anatomically preformed plate osteosynthesis. After a mean follow-up of 10.7 months, the mean Mayo Elbow Performance Score showed an excellent result with 78.89 points. The Quick Disabilities of Arm, Shoulder and Hand (Q-DASH) score showed a median of 18.64 points with a mean functional arc of 118°.

Most coronoid fractures and fracture-dislocations with no radial head involvement can be treated nonsurgically with elbow immobilization

HYPOTHESIS

Conservative treatment of isolated coronoid fractures and fracture-dislocations focused on soft-tissue healing can provide good clinical results in the majority of patients. Our aims were (1) to evaluate the outcome of a conservative treatment protocol designed for isolated coronoid fractures with or without associated elbow dislocations (ICFs) and (2) to characterize the fractures with a dedicated image analysis protocol.

METHODS

Of 38 consecutive patients sustaining acute ICFs, 28 were treated nonsurgically after meeting specific inclusion criteria, prospectively followed up, and clinically evaluated at least 1 year after sustaining their injuries. All cases underwent elbow computed tomography scans with tri-plane and 3-dimensional reconstructions according to a specific protocol referenced to the proximal ulna.

RESULTS

The study included 15 male and 13 female patients, with a mean follow-up period of 32 ± 14 months (range, 12-61 months). An associated dislocation was presented in 8 (29%). Mean extension and flexion were 2° ± 8° (range, -10° to 30°) and 139° ± 11° (range, 110°-155°), respectively. Mean pronation and supination were 74° ± 3° (range, 60°-75°) and 83° ± 9° (range, 40°-85°), respectively. Of the patients, 78% rated their elbow as being normal or nearly normal. The mean Mayo Elbow Performance Score was 95 ± 9 (range, 70-100). The mean Disabilities of the Arm, Shoulder and Hand score was 7 ± 13 (range, 0-57). The mean coronoid fracture height was 5.7 ± 1.2 mm (range, 3.7-7.9 mm). The mean percentage of coronoid height fractured was 33% ± 6% (range, 23%-43%). Mean fracture displacement was 2.7 ± 2 mm (range, 1-9 mm). Of the fractures, 23 (82%) were located at the anteromedial coronoid.

CONCLUSION

An ICF with a perfectly reduced ulnohumeral joint, a competent sublime tubercle, and a fractured coronoid height up to 50% can be treated without surgery with excellent or good results in more than 90% of cases regardless of the location of the fracture in the coronoid or the type of soft tissue-associated disruptions.

The naked capitellum: a surgeon's guide to intraoperative identification of posterolateral rotatory instability

HYPOTHESIS

This study's purpose was to provide a reproducible way for surgeons to intraoperatively assess the elbow's lateral ulnar collateral ligament origin and determine whether there is posterolateral rotatory instability (PLRI) despite an intact common extensor origin (CEO). We hypothesized that we could re-create clinically relevant disruption of lateral supporting structures despite an intact CEO and illustrate progressive elbow PLRI.

METHODS

The relationship of the lateral capsule to the capitellum articular surface was noted in 8 cadaveric upper extremities. The lateral capsule and extensor origin were sequentially sectioned at 4 stages: intact, release to the lateral epicondyle, release of the posterior capsular insertion, and release of the CEO. Posterior and lateral translation of the radial head (RH) relative to the capitellum was measured with the forearm in extension and supination.

RESULTS

The average specimen age was 78.9 years. The lateral capsule originated within 1 to 2 mm of the capitellum articular surface. Lateral capsular sectioning to the 6-o'clock position of the lateral epicondyle created an unstable elbow with posterior and lateral RH translation. Sequential sectioning of the posterior capsular insertion created significant additional RH translation posteriorly (P < .05). With release of the capsule and the extensor origin, the elbow was grossly unstable.

CONCLUSIONS

The elbow's lateral capsuloligamentous complex plays an important role in preventing PLRI. Larger degrees of elbow laxity are associated with further peel back of the capsuloligamentous complex despite an intact CEO. The surgeon must retract the extensor origin intraoperatively to assess for lateral ulnar collateral ligament and/or lateral capsule disruption to prevent a missed case of PLRI.

Insertional anatomy of the anterior medial collateral ligament on the sublime tubercle of the elbow

BACKGROUND

Acute injuries to the anterior medial collateral ligament (AMCL) can occur due to valgus trauma or during other dislocating events to the elbow. AMCL lesions are often associated with bony lesions, such as radial head fractures or fractures of the coronoid process. We analyzed the insertion of the AMCL on the sublime tubercle in relation to surrounding osseous structures. We aimed to increase the understanding of the involvement of the AMCL in bony lesions to the sublime tubercle.

METHODS

We investigated 86 elbows from 43 embalmed human specimens. We measured the most ventral extensions of the AMCL at the sublime tubercle in relation to a clearly defined and reproducible landmark. We used as our landmark a horizontal line (baseline) originating on the lesser sigmoid notch in a right angle to the ulnar ridge.

RESULTS

The mean distance of the coronoid process tip to the baseline was 4.0 mm (standard deviation [SD], 1.3 mm; range, 1.4-6.7 mm). The mean distance of the ventral extension of the AMCL to the horizontal line was 3.7 mm (SD, 2.6 mm; range: 9.4-2.2 mm). The mean horizontal distance between the ventral aspect of the AMCL and the coronoid tip was 13.7 mm (SD, 2.5 mm; range, 7.7-20.5 mm).

CONCLUSIONS

We present a detailed description of the insertional anatomy of the AMCL at the sublime tubercle. These values could be helpful for classifications of coronoid fractures and to estimate the involvement of the AMCL in fractures of the sublime tubercle.

Posteromedial rotatory incongruity of the elbow: a computational kinematics study

BACKGROUND

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.

METHODS

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.

RESULTS

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.

CONCLUSIONS

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.

Varus Posteromedial Rotatory Instability of the Elbow: Injury Pattern and Surgical Experience of 27 Acute Consecutive Surgical Patients

OBJECTIVES

To identify associated injuries that occur in varus posteromedial rotatory instability (VPMRI) of the elbow and present their surgical management.

DESIGN

Level II retrospective study.

SETTING

Tertiary referral center.

PATIENT/PARTICIPANTS

Twenty-seven patients with VPMRI injuries treated surgically over an 8-year period.

INTERVENTION

Open reduction and internal fixation of anteromedial coronoid facet fracture, lateral collateral ligament repair, and associated injured soft-tissue repairs.

MAIN OUTCOME MEASURED

Radiographic classification, associated medial and lateral bony and soft-tissue injuries, surgical fixation method, and complications were recorded.

RESULTS

According to the O'Driscoll classification, there were 15 (55%) type 2-2, 11 (41%) type 2-3, and 1 (4%) type 3-1 fractures. Lateral and medial collateral ligament tears were found in 100% and 63%, respectively. Common extensor and flexor origin injuries occurred in 19 (70%) and 2 (7%) elbows, respectively. A marginal radial head fracture was found in 1 patient. Most patients were treated with a combination of fixation methods. Complications occurred in 7 (26%) patients.

CONCLUSIONS

This study documents both associated findings and surgical fixation methods. In all cases, the lateral collateral ligament was disrupted, often in association with an injured common extensor origin. Medial collateral ligament injuries are commonly involved. Radial head fractures are rarely associated. The surgeon should have a high index of suspicion if an isolated coronoid fracture is encountered. Clinical and functional outcome scores are needed in future studies to further inform treatment of VPMRI of the elbow.

LEVEL OF EVIDENCE

Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

[Research progress of posteromedial rotatory instability of the elbow]

Objective

To summarize the research progress in posteromedial rotatory instability (PMRI) of the elbow joint.

Methods

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.

Results

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.

Conclusion

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.

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

BACKGROUND

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.

MATERIALS AND METHODS

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.

RESULTS

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).

CONCLUSIONS

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.

[Elbow dislocation fractures]

The treatment of complex elbow dislocation fractures is a challenge to both the treating surgeon as well as to the patient due to the complex bony and soft tissue anatomy of the joint. In order to establish an expedient treatment algorithm, all osseous and ligamentous injuries need to be thoroughly assessed. Furthermore, a detailed knowledge of the joint-stabilizing structures, practicable surgical approaches as well as the possible techniques for fracture fixation and/or arthroplasty are essential to facilitate early rehabilitation of the elbow and avoid injury-related complications. Any unnecessary delay in treatment of this complex injury can result in posttraumatic functional disorders, recurrent instability and secondary arthrosis. In conclusion, the goals of surgical treatment must be the correct restoration of the joint anatomy and stability as the prerequisites for any successful treatment of elbow fracture dislocations in order to enable early motion of the joint.

Controversies in Fractures of the Proximal Ulna

The olecranon process, coronoid process, and greater sigmoid notch are important components of the complex proximal ulna. Along with providing bony stability to the ulnohumeral joint, the proximal ulna serves as the attachment site of many important muscles and ligaments that impart soft tissue stability to the elbow joint. Management of proximal ulnar fractures continues to evolve as advances in imaging and anatomic and biomechanical studies have led to improvements in available implants; however, controversies remain, as shown in the current relevant literature.