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Concept: Joint dislocation

169

PurposeIn this retrospective study we investigated the clinical and radiological outcome after operative treatment of acute Rockwood III-V injuries of the AC-joint using two acromioclavicular (AC) cerclages and one coracoclavicular (CC) cerclage with resorbable sutures. METHODS: Between 2007 and 2009 a total of 39 patients fit the inclusion criteria after operative treatment of acute AC joint dislocation. All patients underwent open reduction and anatomic reconstruction of the AC and CC-ligaments using PDS® sutures (Polydioxane, Ethicon, Norderstedt, Germany). Thirty-three patients could be investigated at a mean follow up of 32+/-9 months (range 24–56 months). RESULTS: The mean Constant score was 94.3+/-7.1 (range 73–100) with an age and gender correlated score of 104.2%+/-6.9 (88-123%). The DASH score (mean 3.46+/-6.6 points), the ASES score (94.6+/-9.7points) and the Visual Analogue Scale (mean 0.5+/-0,6) revealed a good to excellent clinical outcome. The difference in the coracoclavicular distance compared to the contralateral side was <5 mm for 28 patients, between 5-10 mm for 4 patients, and more than 10 mm for another patient. In the axial view, the anterior border of the clavicle was within 1 cm (ventral-dorsal direction) of the anterior rim of the acromion in 28 patients (85%). Re-dislocations occured in three patients (9%). CONCLUSION: Open AC joint reconstruction using AC and CC PDS cerclages provides good to excellent clinical results in the majority of cases. However, radiographically, the CC distance increased significantly at final follow up, but neither the amount of re-dislocation nor calcifications of the CC ligaments or osteoarthritis of the AC joint had significant influence on the outcome.Level of evidenceCase series, Level IV.

Concepts: Osteoarthritis, Joint, Joints, Ligament, Joint dislocation, Clavicle, Acromioclavicular joint, Acromion

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INTRODUCTION: We present the case of a patient with extensor carpi ulnaris tendon subluxation who was first treated for distal radioulnar joint sprain. CASE PRESENTATION: A 25-year-old Caucasian man was seen at our policlinic one month after he had fallen on his outstretched hand. A diagnosis of extensor carpi ulnaris subluxation was made clinically but we also had the magnetic resonance imaging scan of the patient’s wrist which displayed an increased signal on T2-weighted images consistent with inflammation around the extensor carpi ulnaris tendon. The extensor carpi ulnaris tendon was found to be dislocating during supination and relocating during pronation. The sheath was reconstructed using extensor retinaculum due to attenuation of subsheath. CONCLUSION: There was no recurrent dislocation of the extensor carpi ulnaris tendon of the patient at his last follow up 12 months after the operation.

Concepts: Nuclear magnetic resonance, Magnetic resonance imaging, Wrist, Joint dislocation, Distal radioulnar articulation, Extensor carpi ulnaris muscle, Extensor carpi radialis longus muscle, Proximal radioulnar articulation

28

Acute acromioclavicular joint dislocations indicated for surgery can be treated with several stabilization techniques. This in vitro study evaluated the acromioclavicular joint stability after 3 types of validated repair techniques compared with the native situation.

Concepts: Synovial joint, Joints, Joint dislocation, Acromioclavicular joint, Acromioclavicular ligament

27

Immobilization of the shoulder in 60 ° external rotation and 30 ° abduction after primary anterior shoulder dislocation has been shown to allow anatomical reduction and potential healing of the capsule-labrum complex. The purpose of the present study was to evaluate commercially available shoulder braces concerning functionality and comfort as well as for potential problems.

Concepts: Present, Shoulder, Joint dislocation, Dislocated shoulder

27

PURPOSE: Acute elbow instability leading to dislocation is thought to be a spectrum initiated by an injury to the lateral stabilizing structures of the elbow. Previous cadaveric studies have shown elbow dislocations to occur in flexion. The purpose of this study was to analyze videographic evidence of the deforming forces and upper extremity position during elbow dislocations. We sought to corroborate previous biomechanics studies with in vivo observations. METHODS: We included 62 YouTube.com videos with a clear videographic view of an elbow dislocation. Three senior elbow surgeons independently evaluated arm position at the time of dislocation, along with the suspected deforming forces at the elbow based on these positions. RESULTS: Of the 62 visualized elbow dislocation events, the vast majority (92%) dislocated at or near full extension. The most common arm positions were forearm pronation (68%) with shoulder abduction (97%) and forward flexion (63%). The typical elbow deforming forces were a valgus moment (89%), an axial load (90%), and progressive supination (94%). We identified 4 discrete patterns of arm position and deforming forces. CONCLUSIONS: Acute elbow dislocations in vivo occur in relative extension irrespective of forearm position, a finding distinct from previous cadaveric studies. The most common mechanism appears to involve a valgus moment to an extended elbow, which suggests a requisite disruption of the medial collateral ligament, the known primary constraint to valgus force. These videographic findings suggest that some acute elbow dislocations may result from acute valgus instability and therefore are distinct in nature and mechanism from posterolateral rotatory instability. This information could lead to improved understanding of the sequence of structural failure, modification of rehabilitation protocols, and overall treatment. TYPE OF STUDY/LEVEL OF EVIDENCE: Diagnostic IV.

Concepts: Knee, Shoulder, Forearm, Upper limb, Joint dislocation, Work hardening, Dislocation, Pronation

27

The present multicenter, prospective study evaluated the subjective outcomes in patients after extraosseous talotarsal stabilization using the HyProCure(®) stent as a standalone procedure for the treatment of recurrent and/or partial talotarsal joint dislocation (RTTD) in a population of pediatric and adult patients. RTTD has been cited as a possible etiology for a number of foot ailments and might contribute to the development of pathologic features localized more proximally in the weightbearing musculoskeletal chain. Correction of RTTD might, therefore, lead to the reduction of pathologic features associated with this deformity. A total of 46 feet in 35 patients were included in the present investigation. Subjective evaluation used the Maryland Foot Score assessment, which was obtained preoperatively and 1, 2, and 3 weeks, 1, 2, 3, and 6 months, and 1 year postoperatively. The mean overall scores improved from a preoperative value of 69.53 ± 19.56 to a postoperative value of 89.17 ± 14.41 at the 1-year follow-up. Foot pain decreased by 36.97%, foot functional activities improved by 14.39%, and foot appearance improved by 29.49%. The greatest magnitude of improvement occurred 4 weeks postoperatively, with gradual improvement continuing through to the 1-year follow-up. Implants were removed from 2 patients (2 feet, 4.35%). No unresolved complications were observed. The positive subjective outcomes resulting from the extraosseous talotarsal stabilization procedure suggest that the intervention employing the device we have described alleviates pain and improves foot function and appearance in patients with RTTD.

Concepts: Present, Better, Improve, Foot, Joint dislocation, Case series, Imperial units

25

Anterior-posterior stability in an unconstrained mobile-bearing total knee arthroplasty (TKA) and one with rotational constraints is compared in a computational model based on an ASTM test. Both TKA designs dislocate at loads greater than reported maximum in vivo forces. The posterior drawer forces (mean: 3027 N vs. 1817 N) needed to induce subluxation increase with a greater anterior jump distance (12 mm vs. 7 mm; refers to the vertical height of the anterior or posterior border of the tibial insert’s articulating surface). The posterior jump distance for both tested TKA differed by 1.5 mm and had minimal effect on the magnitude of the anterior drawer forces at dislocation in mid-flexion (unconstrained vs. constrained: 445 N vs. 412 N). The unconstrained insert dislocated by means of spin-out whereas in the constrained TKA the femur dislocated from the bearing during posterior drawer and the bearing from the baseplate during anterior drawer. MCL function is an important consideration during ligament balancing since a ± 10% variation in MCL tension affects dislocation forces by ± 20%. The simulation platform provided the means to investigate TKA designs in terms of anterior-posterior stability as a function of knee flexion, collateral ligament function and mechanical morphology.

Concepts: Knee, Knee replacement, Computational model, Joint dislocation, Dislocation

20

Ehlers-Danlos syndrome (EDS)-hypermobility type (HT) is considered to be the most common subtype of EDS and the least severe one; EDS-HT is considered to be identical to the joint hypermobility syndrome and manifests with musculoskeletal complaints, joint instability, and soft tissue overuse injury. Musculoskeletal complaints manifest with joint pain of non-inflammatory origin and/or spinal pain. Joint instability leads to dislocation or subluxation and involves peripheral joints as well as central joints, including the temporomandibular joints, sacroiliac joints, and hip joints. Soft tissue overuse injury may lead to tendonitis and bursitis without joint inflammation in most cases. Ehlers-Danlos syndrome-HT carries a high potential for disability due to recurrent dislocations and subluxations and chronic pain. Throughout the years, extra-articular manifestations have been described, including cardiovascular, autonomic nervous system, gastrointestinal, hematologic, ocular, gynecologic, neurologic, and psychiatric manifestations, emphasizing the multisystemic nature of EDS-HT. Unfortunately, EDS-HT is under-recognized and inadequately managed, leading to neglect of these patients, which may lead to severe disability that almost certainly could have been avoided. In this review article we will describe the known manifestations of the extra-articular systems.

Concepts: Joint, Marfan syndrome, Sacroiliac joint, Joints, Ehlers-Danlos syndrome, Temporomandibular joint, Joint dislocation, Hypermobility

4

Dislocations of the sternoclavicular joint (SCJ) occur with relative infrequency and can be classified into anterior and posterior dislocation, with the former being more common. The SCJ is inherently unstable due to its lack of articular contact and therefore relies on stability from surrounding ligamentous structures, such as the costoclavicular, interclavicular and capsular ligaments. The posterior capsule has been shown in several studies to be the most important structure in determining stability irrespective of the direction of injury. Posterior dislocation of the SCJ can be associated with life threatening complications such as neurovascular, tracheal and oesophageal injuries. Due to the high mortality associated with such complications, these injuries need to be recognised acutely and managed promptly. Investigations such as X-ray imaging are poor at delineating anatomy at the level of the mediastinum and therefore CT imaging has become the investigation of choice. Due to its rarity, the current guidance on how to manage acute and chronic dislocations is debatable. This analysis of historical and recent literature aims to determine guidance on current thinking regarding SCJ instability, including the use of the Stanmore triangle. The described methods of reduction for both anterior and posterior dislocations and the various surgical reconstructive techniques are also discussed.

Concepts: Osteoarthritis, Joint, Joints, Ligament, Instability, Joint dislocation, Sternoclavicular articulation, Costoclavicular ligament

4

Most emergency physicians routinely obtain shoulder radiographs before and after shoulder dislocations. However, currently there is limited literature demonstrating how frequently new fractures are identified on post-reduction radiographs. The primary objective of this study was to determine the frequency of new, clinically significant fractures identified on post-reduction radiographs with a secondary outcome assessing total new fractures identified.

Concepts: Primary education, Shoulder, Joint dislocation, Dislocation, Plasticity