Posteromedial Rotatory Instability Research Articles

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

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). 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. The operation time was 85.9 ± 11.06min (range 65-110). The intraoperative blood loss was 70.7 ± 9.31ml (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 2months after operation and was treated with ulnar nerve release. The symptom of numbness went away completely 1week after operation. No complications such as wound infection, arthritis, or chronic instability of the elbow were found in the other patients. 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 IV; Retrospective studies.

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

BackgroundFracture 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. MethodsThis 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. ResultsFifteen 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). ConclusionsBoth surgical and conservative treatment for AMF fractures resulted in satisfactory final clinical outcomes. However, high complication and reoperation rates were observed.

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 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.

Coronoid reconstruction with autologous iliac crest bone graft in chronic elbow instability through amedial approach

Neutralizing a posteromedial rotatory instability (PMRI) caused by coronoid deficiency by restoration of the humeroulnar joint surface with an autologous iliac crest bone graft. Surgery is indicated in patients with chronic deficiency of the anteromedial facet of the coronoid with subsequent PMRI. Coronoid reconstruction is not recommended in patients with advanced osteoarthritis of the elbow caused by subluxation of the humeroulnar joint. General contraindications like acute infection, pregnancy and lack of operability should also be taken into account. First, amedial approach is established and the base of the coronoid is prepared. Afterwards an autologous iliac crest bone graft is placed onto the defect and secured by screws or aplate. In addition, a reconstruction of the anterior bundle of the medial collateral ligament with an autologous tendon graft is performed. An elbow orthesis is worn for 6weeks after surgery to avoid valgus or varus stress. There is no restriction in range of motion. Acontinuous passive motion elbow chair supports the patient in regaining elbow mobility. Between 2015 and 2017, we treated 10patients suffering from chronic coronoid defects with coronoid reconstruction. Eight of the patients were available for follow-up 86weeks after surgery. The mean age was 41.4years. In all patients, elbow range of motion and patient-related outcome measures were improved after surgery. Plain radiographs illustrated correct centering of the elbow joint. One patient had to undergo elbow arthroplasty and was excluded. Coronoid reconstruction with an autologous iliac crest bone graft restored humeroulnar joint congruency and improved satisfaction in patients suffering from chronic coronoid deficiency.

Operative Fixation of the Anteromedial Facet of the Coronoid Process.

Anteromedial coronoid facet fractures typically occur with varus, pronation, and axial forces applied to the elbow. Due in part to the high rate of concomitant lateral collateral ligament (LCL) injuries, untreated anteromedial facet fractures can result in varus and posteromedial rotatory elbow instability. Although small fractures that are not amenable to open reduction and internal fixation can be treated with isolated LCL repair, larger fragments are treated with buttress plating on the anteromedial surface of the coronoid with or without LCL repair. The "over-the-top" approach via a split in the flexor pronator mass is the preferred method of accessing the anteromedial facet. Although data regarding the functional outcomes after operative fixation of the anteromedial facet are limited, observational studies have demonstrated good restoration of elbow stability and motion.

Clinical treatment of dorsal avulsion fracture of the capitellum combined with medial or posterior medial dislocation of the elbow joint

To analyze the possible injury mechanisms in patients with dorsal avulsion fracture of the capitellum combined with medial or posterior medial dislocation of the elbow joint, and to discuss their treatment and prognosis. Retrospective analysis was made on the clinical data of 4 patients with dorsal avulsion fracture of the capitellum combined with medial or posterior medial dislocation of the elbow joint admitted between September 2014 and September 2020, including 3 males and 1 female with an average age of 20.7 years (range, 13-32 years). There were 2 cases of dorsal avulsion fracture of the capitellum combined with medial dislocation of the elbow joint and 2 cases of dorsal avulsion fracture of the capitellum and anterior medial fracture of the coronoid process combined with posterior medial subluxation of the elbow joint. Closed reduction was performed in 3 patients with fresh fracture combined with dislocation, then 2 cases were fixed with tension band and 1 case was fixed with tension band combined with Acumed coronoid anatomic plate. And in patient with old fracture nonunion, the coronoid process was fixed with 1 screw, then the humeral sclerotic bone mass was removed, and finally the lateral collateral ligament was repaired and a hinged external fixator was added. All the incisions healed by first intention without early complications such as infection or peripheral nerve injury. The 4 patients were followed up 13-30 months (mean, 20.8 months). The fractures all healed with a healing time of 70-90 days (mean, 79.5 days). At 6 months after operation, heterotopic ossification was seen in the posterior aspect of the right elbow joint in 1 case, and the alkaline phosphatase level was normal (67 U/L); the tension band was removed to clear the heterotopic ossification and the elbow joint was released. The rest of the patients had no heterotopic ossification. At last follow-up, all patients had good functional recovery of the elbow joint, with a Mayo score of 85-100 (mean, 92.5), and the excellent and good rate was 100%. The elbow flexion range of motion was 120°-135°, the extension range of motion was 10°-20°, and the pronation and supination range of motion were all 75°-85°. Dorsal avulsion fractures of the capitellum combined with medial or posterior medial dislocation of the elbow may be due to simple varus stress. If an anteromedial coronoid facet fracture also occurs, it may be for the varus posteromedial rotatory instability, which is the opposite mechanism to that of an Osborne-Cotterill lesion. For fresh dorsal avulsion fractures of the capitellum, tension band fixation can be used with good results.

Internal joint stabilizer for varus posteromedial rotatory instability of the elbow.

Management of varus posteromedial rotatory instability (VPMRI) of the elbow presents a challenging problem, sometimes requiring supplemental external fixation or ulnohumeral cross-pinning. A relatively new treatment adjunct for posterolateral rotatory instability of the elbow has become available with the development of the internal joint stabilizer (IJS) implant. However, this has not been studied for VPMRI because the implant is thought to be ineffective at treating this instability when placed in the usual manner on the lateral side of the elbow. We hypothesize that modifying the IJS technique to place the implant medially will make it as effective as external fixation at preventing VPMRI. Nine whole-arm cadaveric specimens were tested on a rig that allowed for gravity stress of the elbow at 60° of abduction. Intact specimens (INT) were tested to find the baseline stability with all structures intact. Then, O'Driscoll type 2-subtype III coronoid fractures were created with a microsagittal saw, and these same specimens were again tested without any fixation (WAF), with a static lateral external fixator (SLEF), and with a medially placed IJS (MIJS). The method for medial IJS placement is detailed within. The WAF specimens were significantly more unstable than the INT, SLEF, and MIJS groups (P < .001). There was no difference in stability between the INT and the SLEF (P = .59) or MIJS group (P = .21). In this cadaveric model, a medially placed IJS was as effective as an SLEF at maintaining elbow stability in a coronoid-deficient elbow. This technique allows for early elbow range of motion, with no external hardware, and may eliminate the complications associated with external fixation or ulnohumeral cross-pinning.

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

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

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

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]). 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. 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 subtype3. 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.

Soft tissue injury patterns in posteromedial rotatory instability with dislocation compared with posteromedial dislocation of the elbow joint

We sought to determine injury mechanisms and soft tissue injury patterns of dislocation caused by posteromedial rotatory instability (PMRI) and simple posteromedial (PM) dislocation of the elbow joint that appear similar on simple radiographs. In this retrospective case-series study, we reviewed 13 patients with PMRI dislocation and 10 patients with simple PM dislocation. Three-dimensional computed tomography and magnetic resonance imaging were performed in both groups. The ulnar collateral ligament, lateral collateral ligament complex (LCLC), overlying extensor muscle, and locus of bone contusion were identified. The direction of dislocation was categorized into the pure-posterior or PM type by simple radiographs. The LCLC was completely ruptured in both groups. A completely torn ulnar collateral ligament was observed in 3 patients (23%)in the PMRI dislocation group and 9 patients (90%)in the simple PM dislocation group (P = .005). Regarding injury patterns of the LCLC and overlying extensor muscle, the distraction type was found in 10 patients (77%) and the stripping type was found in 3 patients (23%) in the PMRI dislocation group, whereas all patients (100%) in the simple PM dislocation group had the distraction type (P = .103). Bone contusion was observed at the posterolateral olecranon in 2 patients (15%)in the PMRI dislocation group andat the PM olecranon in 4 patients (40%),posterolateral olecranon in 1 (10%),posterior olecranon in 1 (10%), and PM-posterolateral olecranon in 1 (10%) in the simple PM dislocation group (P = .008). In the PMRI dislocation group, 7 patients (54%) had the PM type and 6 (46%) had the pure-posterior type. Simple PM and PMRI dislocations of the elbow joint might have different soft tissue injury characteristics because of different injury mechanisms.

Buttress plate fixation of coronoid process fractures via a medial approach

PurposeTo assess the clinical and radiographic outcomes of coronoid process fractures surgically managed with buttress plate fixation via a medial approach. MethodsA retrospective review of all coronoid fractures surgically fixed in our institution using a buttress plate technique via a medial approach between June 2012 and April 2015 by the senior author was performed. These fractures were all sizeable fractures contributing to persistent elbow instability in terrible triad or varus posteromedial rotatory instability injury patterns. A prospective telephone questionnaire was conducted to assess patient outcomes using the disabilities of the arm, shoulder and hand (DASH) score and Mayo hlbow performance score (MEPS). ResultsTwelve patients were included in the study, comprising 10 males and 2 females with an average age of 39 years (range, 19–72 years). Mean follow-up was 16 months (range, 4–18 months). The average time to radiographic union was 4 months (range, 3–7 months). Range of motion measurements at final follow-up were obtained in 11 out of 12 patients, with one patient defaulting follow-up. All 11 patients displayed a functional elbow range of motion of at least 30°-130°, with an average arc of motion of 130° (range, 110° −140°), mean elbow flexion of 134° (range, 110° −140°) and mean flexion contracture of 3° (range, 0° −20°). The mean DASH score was 16 (range, 2.5–43.8) and the mean MEPS was 75 (range, 65–100). Complications observed included one patient with a superficial wound infection which resolved with a course of oral antibiotics and one patient with radiographic evidence of heterotopic ossification which was conservatively managed. No residual elbow instability was observed and no reoperations were performed. ConclusionButtress plate fixation via a medial approach of coronoid process fractures that contribute to persistent elbow instability represents a reliable method of treatment that produces satisfactory and predictable outcomes.

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.

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

To identify associated injuries that occur in varus posteromedial rotatory instability (VPMRI) of the elbow and present their surgical management. Level II retrospective study. Tertiary referral center. Twenty-seven patients with VPMRI injuries treated surgically over an 8-year period. Open reduction and internal fixation of anteromedial coronoid facet fracture, lateral collateral ligament repair, and associated injured soft-tissue repairs. Radiographic classification, associated medial and lateral bony and soft-tissue injuries, surgical fixation method, and complications were recorded. 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. 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. Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

The role of the posterior bundle of the medial collateral ligament in posteromedial rotatory instability of the elbow.

The aim of this study was to evaluate two hypotheses. First, that disruption of posterior bundle of the medial collateral ligament (PMCL) has to occur for the elbow to subluxate in cases of posteromedial rotatory instability (PMRI) and second, that ulnohumeral contact pressures increase after disruption of the PMCL. Six human cadaveric elbows were prepared on a custom-designed apparatus which allowed muscle loading and passive elbow motion under gravitational varus. Joint contact pressures were measured sequentially in the intact elbow (INTACT), followed by an anteromedial subtype two coronoid fracture (COR), a lateral collateral ligament (LCL) tear (COR + LCL), and a PMCL tear (COR + LCL + PMCL). There was no subluxation or joint incongruity in the INTACT, COR, and COR + LCL specimens. All specimens in the COR + LCL + PMCL group subluxated under gravity-varus loads. The mean articular contact pressure of the COR + LCL group was significantly higher than those in the INTACT and the COR groups. The mean articular contact pressure of the COR + LCL + PMCL group was significantly higher than that of the INTACT group, but not higher than that of the COR + LCL group. In the presence of an anteromedial fracture and disruption of the LCL, the posterior bundle of the MCL has to be disrupted for gross subluxation of the elbow to occur. However, elevated joint contact pressures are seen after an anteromedial fracture and LCL disruption even in the absence of such subluxation. Cite this article: Bone Joint J 2018;100-B:1060-5.

Anteromedial fractures of the ulnar coronoid process: correlation between surgical outcomes and radiographic findings

BackgroundThis study aimed to report the radiographic findings and surgical outcomes of anteromedial facet (AMF) fracture of the ulnar coronoid process and to suggest an optimal approach.MethodsIn this retrospective study, 20 consecutive patients with unilateral AMF fracture of coronoid process were surgically treated and divided into two groups without (group A) and with (group B) additional proximal ulnar fractures in equal case number. Time from injury to surgery averaged 4.38 ± 2.56 weeks. Mayo Elbow Performance Score (MEPS) and Shortened Disability of the Arm and Shoulder and Hand (quickDASH) score were used for functional evaluation. Cohen kappa coefficient (kappa) analysis was used to determine interobserver reliability on a radiographic reading.ResultsAll cases had a mean follow-up of 2.3 years. MEPS at 2 years averaged 87.75 ± 12.51; quickDASH, 7.05 ± 6.19. A significantly higher MEPS was found in subtype 3 than in subtype 2 (p = 0.036) and in group B than in group A (p = 0.020). Significantly lower quickDASH cores were found in group B than in group A (p = 0.011). Kappa analysis showed moderate agreement in the O’Driscoll classification (kappa = 0.56) and substantial agreement in categorization of the additional proximal ulnar fractures (kappa = 0.76).ConclusionsAdditional proximal ulnar lesions were considered an integral part of varus posteromedial rotatory instability and required further categorization in the management of AMF fractures. Significantly better functional outcomes were achieved when those lesions were fully addressed.

Varus posteromedial rotatory instability: a biomechanical analysis of posterior bundle of the medial ulnar collateral ligament reconstruction

Recently, there has been growing interest in the involvement of the posterior bundle of the medial ulnar collateral ligament (pMUCL) in varus posteromedial rotatory instability (PMRI). Varus PMRI has been observed clinically, but the degree of involvement of the pMUCL remains unclear. This study assessed the degree to which the pMUCL is involved in stabilizing the elbow and the feasibility of a pMUCL reconstruction to restore stability. Movements simulating PMRI were performed in 8 cadaveric elbows. Joint gapping values were obtained by 3-dimensional motion capture for the proximal and distal aspects of the ulnohumeral joint. Specimens were assessed at "intact," "cut coronoid + pMUCL," "reconstruction," and "cut anterior aspect MUCL + reconstruction" conditions with mechanical testing at 30°, 60°, and 90° of elbow flexion. Proximal joint gapping significantly increased from intact to cut coronoid + pMUCL at 60° and 90°, and distal joint gapping significantly increased at 90°. In the reconstruction condition, joint gapping across the proximal joint at 60° and 90° significantly recovered, as did distal joint gapping at 90°. In the cut anterior aspect MUCL + reconstruction condition, no significant increase occurred in proximal or distal joint gapping. Transection of the pMUCL with a coronoid fracture leads to increased joint gapping, suggesting the presence of PMRI. PMRI can still occur with an intact lateral ligamentous complex. A pMUCL tendon graft reconstruction confers some elbow stability in this injury mechanism.

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.