Stabilizing effect of an elbow orthosis with an adjustable hinge axis after lateral collateral ligament injury: A biomechanical study.

Background: Current commercial elbow braces have a straight hinge that does not account for the native carrying angle of the elbow. The objective of this study was to determine the effectiveness of a custom-designed hinged elbow orthosis (HEO) with variable valgus angulations in stabilizing a lateral collateral ligament (LCL) deficient elbow. Methods: Eight cadaveric upper extremities were mounted in an elbow motion simulator in the abducted varus gravity-loaded position. The specimens were examined before and after simulated LCL injury and then with the addition of the custom-designed HEO with 0°, 10°, and 20° of valgus angulation. Kinematic data were recorded using an electromagnetic tracking system. Results: The LCL injured state with or without the brace resulted in significant increases in varus angulation of the elbow compared to the intact state in both pronation and supination (P < 0.05). There were no significant differences in varus-valgus angulation or ulnohumeral rotation between any of the brace angles and the LCL injured state with the forearm pronated and supinated. Discussion: The custom-designed HEO did not provide any additional stability to the LCL injured elbow. The varus arm position should be avoided during the rehabilitation of an LCL injured elbow even when an HEO is used.

Traumatic Volar Carpal Instability Nondissociative: A Case Series.

Carpal instability nondissociative (CIND) involves disruption between carpal rows from injury to extrinsic and intrinsic wrist ligaments. CIND traumatic (CINDT) highlights the posttraumatic etiology of some of these cases and has been gaining increasing attention in the literature. We present four cases of CINDT-volar intercalated segmental instability (VISI). We diagnosed two adults with distal radius fractures and two adolescents with Galeazzi fractures, all treated surgically, who developed CINDT-VISI with radiolunate angles greater than 15° at 2 weeks after surgery. One adult had progressive deformity but was asymptomatic at 33 months. The other underwent volar capsular release at 1 year to improve alignment. One adolescent with a fixed deformity required soft tissue releases and temporary pinning to restore alignment at 7 months. We treated the other successfully with early physiotherapy. No patient had radiographic signs of arthritis at 1-2 years. This is the first reported association between Galeazzi fractures and CINDT-VISI. Contrary to existing literature, we report successful outcomes with nonsurgical and delayed nonfusion surgery of CINDT-VISI.

The effect of lateral collateral ligament repair tension on elbow stability: An in vitro biomechanical study.

BACKGROUND: The aim of this study was to determine the optimal repair tension of the lateral collateral ligament of the elbow by performing simulated active flexion with the arm in the varus gravity loaded position using an in vitro elbow simulator. METHODS: Eight cadaveric specimens were mounted in the varus gravity loaded orientation onto an elbow motion simulator. Four states were studied (intact, lateral collateral ligament injured, and 15 N and 20 N lateral collateral ligament repairs) with the forearm in supination and pronation. An electromagnetic tracking system was used to measure joint kinematics during active elbow flexion. FINDINGS: There was no difference in ulnohumeral rotation between the intact state and the 15 N repair (P = .150 for pronation; P = 1.0 for supination) or the 20 N repair (P = 1.0 for pronation; P = .568 for supination). For varus-valgus angulation, the 20 N repair was not statistically different from the intact state (P = .059 in pronation; P = 1.0 in supination). INTERPRETATION: Repair of the lateral collateral ligament following injury can restore joint kinematics with the arm in the varus position. A repair tension of 20 N was successful in restoring joint stability for simulated active motion with the forearm in pronation and supination. This study shows that when the lateral collateral ligament is repaired with adequate tension, avoidance of the varus position may not be as crucial during early motion.

Cannabis use patterns among patients with upper extremity conditions at the time of legalization in Canada.

BACKGROUND: Recreational cannabis use was legalized in Canada in 2018. Cannabis use patterns and patient attitudes toward cannabis use, particularly in the context of these legal changes, are not well understood. Our aim was to evaluate baseline cannabis use patterns and attitudes at the time of legalization among patients with upper extremity conditions in Canada. METHODS: In 2018, we conducted a multicentre cross-sectional survey study of 1561 patients with upper extremity conditions at 7 surgical centres. Participants were asked whether they currently use cannabis. If yes, they were asked questions regarding usage patterns and perceptions of cannabis use, including likelihood of use, safety and comfort discussing it with their physician. RESULTS: In the 6 months after legalization, 790 (51%) participants felt that cannabis was safer than prescription narcotics, with 450 (29%) currently using cannabis. Reasons for cannabis use included pain (56%), stress (51%) and recreation (42%). Of the 1105 patients not using cannabis, 267 (24%) were more likely to consider it after legalization. Of the 450 cannabis users, 73 (16%) had been using it for less than 6 months, 206 (46%) stated they were more comfortable discussing cannabis with their physician after legalization and 195 (43%) were using cannabis more than 4 times per week. CONCLUSION: Many patients with upper extremity conditions were regularly using cannabis. Patients were more comfortable discussing cannabis with their physician than before legalization. Treating surgeons should be aware of these trends and expect to receive questions regarding cannabis use.

Primary total elbow arthroplasty.

There have been significant improvements in surgical techniques and implant designs of elbow arthroplasty over the last five decades. These advances have resulted in improved outcomes and expansion of indications for total elow arthroplasty (TEA). As the proportion of TEAs being performed for inflammatory arthritis has been decreasing in recent years, TEAs are being performed more commonly for the management of acute distal humerus fractures in the elderly, post-traumatic sequelae, and primary osteoarthritis. Appropriate patient selection and meticulous attention to surgical technique including the surgical approach, implant positioning and fixation will result in acceptable outcomes. Future advances in the design, instrumentation, and surgical technique will allow for further improvement in outcomes as the indications for TEA continue to expand.

The role of biceps loading and muscle activation on radial head stability in anterior Monteggia injuries: An in vitro biomechanical study.

INTRODUCTION: Little evidence-based information is available to direct the optimal rehabilitation of patients with anterior Monteggia injuries. PURPOSE OF THE STUDY: The aims of this biomechanical investigation were to (1) quantify the effect of biceps loading and (2) to compare the effect of simulated active and passive elbow flexion on radial head stability in anterior Monteggia injuries. STUDY DESIGN: In vitro biomechanical study. METHODS: Six cadaveric arms were mounted in an elbow motion simulator. The effect of biceps loading, simulated active and passive elbow flexion motions was examined with application of 0N, 20N, 40N, 60N, 80N, and 100N of load. Simulated active and passive elbow flexion motions were then performed with the forearm supinated. Radial head translation relative to the capitellum was measured using an optical tracking system. After testing the intact elbows, the proximal ulna was osteotomized and realigned using a custom jig to simulate an anatomical reduction. We then sequentially sectioned the anterior radiocapitellar joint capsule, annular ligament, quadrate ligament, and the proximal and middle interosseous membrane to simulate soft tissue injuries commonly associated with anterior Monteggia fractures. RESULTS: Greater magnitudes of biceps loading significantly increased anterior radial head translation. However, there was no significant difference in radial head translation between simulated active and passive elbow flexion except in the final stage of soft tissue sectioning. There was a significant increase in anterior radial head translation with progressive injury states with both isometric biceps loading and simulated active and passive motion. CONCLUSIONS: Our results demonstrate that anatomic reduction of the ulna may not be sufficient to restore radial head alignment in anterior Monteggia injuries with a greater magnitude of soft tissue injury. In cases with significant soft tissue injury, the elbow should be immobilized in a flexed and supinated position to allow relaxation of the biceps and avoid movement of the elbow in the early postoperative period.

Effect of ulnar angulation and soft tissue sectioning on radial head stability in anterior Monteggia injuries: an in vitro biomechanical study.

BACKGROUND: Radial head instability continues to be a challenge in the management of anterior Monteggia injuries; however, there is a paucity of literature on the factors that contribute to this instability. The aim of this biomechanical investigation was to examine the effects of ulnar angulation and soft tissue insufficiency on radial head stability in anterior Monteggia injuries. METHODS: Six cadaveric arms were mounted in an elbow motion simulator. Radial head translation was measured during simulated active elbow flexion with the forearm supinated. After testing the elbows in the intact state, the ulna was osteotomized and tested at 0°, 10°, 20°, and 30° of extension angulation. To examine the effect of soft tissue insufficiency, the anterior radiocapitellar joint capsule, annular ligament, quadrate ligament, and the proximal and middle interosseous membrane (IOM) were sequentially sectioned. RESULTS: There was a significant increase in anterior radial head translation with greater ulnar extension angulation. Sequential soft tissue sectioning also significantly increased anterior radial head translation. There was no increase in radial head translation with isolated sectioning of the anterior radiocapitellar joint capsule. Additional sectioning of the annular ligament and quadrate ligament slightly increased anterior radial head translation but did not reach statistical significance. Subsequent sectioning of the proximal and middle IOM resulted in significant increases in anterior radial head translation. CONCLUSION: Our study demonstrates that progressive ulnar extension angulation results in an incremental increase in anterior radial head translation in anterior Monteggia injuries. Moreover, increasing magnitudes of soft tissue disruption result in greater anterior radial head instability.

Analysis of Three-Dimensional Anatomical Variance and Fit of the Distal Radius to Current Volar Locking Plate Designs.

Purpose: Distal radius fractures are the most common upper-extremity fracture and are increasingly being treated surgically with precontoured volar locking plates. It is not currently known whether existing implant designs are anatomically accurate and whether this has clinical implications. The objective of this study was to determine whether anatomic alignment of the distal radius corresponds accurately to modern volar locking plate designs, including any sex-linked differences in morphology of the distal radius. It was hypothesized that the 2 plates examined would show differences in watershed line (WSL) overlap and that female specimens would have a larger overlap compared with males owing to a decrease in plate-WSL border distances. Methods: We used 3-dimensional models of 20 cadaver arms (10 female: mean age, 88.7 ± 4.6 years [range, 82-97 years]; and 10 male: mean age, 86 ± 3.6 years [range, 81-91 years]) to create 3-dimensional computed tomography models of the distal radius. Virtual models of 2 common volar plates were created and were used to place the plate virtually onto the distal radii. Outcome measures included the volar cortical angle of the bone and plate, the definition of the WSL subsequently followed by quantitative distance and overlap measures, and percent contact between the plate and the distal radius. Results: Both sexes showed an decrease (approximately 7°) in average volar cortical angle measure from medial to lateral columns that was statistically significantly smaller on the lateral column (males: 38°; females: 29°) compared with the medial column (males: 45°; females: 36°). Watershed line overlap ranged from 0% to 34.8% with statistically significant differences between sexes. Average border distance for females was 2.7 mm, compared with 3.8 mm for males. Maximum percent contact of 22.0% was observed at a 0.3-mm threshold. Conclusions: Distal radius fractures are common in elderly female patients, yet clinically available plates have important differences in WSL overlap between sexes, and with minimal contact. Female specimens had more WSL overlap than did males. This indicates the need for volar locking plates to be redesigned to factor in anatomical features of individual patients with a particular focus on sex differences. Clinical relevance: New plate designs should focus on providing smaller head sizes that are more accurately tailored to the natural contours of the volar distal radius. It is recommended that future studies incorporate expertise from multiple surgeons to diversify and further understand plate placement strategies.

The effect of torsional moments on the posterolateral rotatory stability of a lateral ligament deficient elbow: An in vitro biomechanical investigation.

BACKGROUND: Clinical tests for posterolateral rotatory instability of the elbow apply external torsional moments to the forearm; however, biomechanical studies of lateral collateral ligament injuries and their surgical repair, reconstruction and rehabilitation have primarily relied on varus gravity loading to quantify instability. The aim of this investigation was to determine the effect of torsional moments on the posterolateral rotatory instability of the lateral ligament deficient elbow. METHODS: Six cadaveric arms were tested in an elbow motion simulator with the arm in the varus position. A threaded outrigger was inserted on the dorsal aspect of the proximal ulna to suspend 400 g, 600 g, and 800 g of weight to allow torsional moments of 0.12, 0.18, and 0.23 Nm respectively on the ulna. An injured model was created by sectioning of the common extensor origin, and the lateral collateral ligament. FINDINGS: During simulated active flexion with the arm in varus, the injured model resulted in a significant increase in external rotation of the ulnohumeral articulation with the forearm both pronated and supinated (pronation: P = .021; supination: P = .015). The application of torsional moments to the lateral ligament deficient elbow resulted in a significant increase in the posterolateral rotatory instability of the elbow. INTERPRETATION: This investigation demonstrates that the application of even small amounts of external torsional moments on the forearm with the arm in the varus position increases the rotational instability of the lateral ligament deficient elbow. During clinical examination for posterolateral rotatory instability and biomechanical studies of lateral ligament injury, the application of external torsion to the forearm should be considered to detect subtle instability. LEVEL OF EVIDENCE: Basic Science Study.

Role of the anconeus in the stability of a lateral ligament and common extensor origin-deficient elbow: an in vitro biomechanical study.

BACKGROUND: The role of the anconeus in elbow stability has been a long-standing debate. Anatomic and electromyographic studies have suggested a potential role as a stabilizer. However, to our knowledge, no clinical or biomechanical studies have investigated its role in improving the stability of a combined lateral collateral ligament and common extensor origin (LCL + CEO)-deficient elbow. METHODS: Seven cadaveric upper extremities were mounted in an elbow motion simulator in the varus position. An injured model was created by sectioning of the CEO and the LCL. The anconeus tendon and its aponeurosis were sutured in a Krackow fashion and tensioned to 10 N and 20 N using a transosseous tunnel. Varus-valgus angles and ulnohumeral rotations were recorded using an electromagnetic tracking system during simulated active elbow flexion with the forearm pronated and supinated. RESULTS: During active motion, the injured model resulted in a significant increase in varus angulation (P = .0001 for pronation; P = .001 for supination) and external rotation (P = .001 for pronation; P = .003 for supination) of the ulnohumeral articulation compared with the intact state. Tensioning of the anconeus significantly decreased the varus angulation (P = .006 for 10 N pronation; P = .0001 for 20 N pronation; P = .0001 for 10 N supination; P = .0001 for 20 N supination) and external rotation angle (P = .008 for 10 N pronation; P = .0001 for 20 N pronation; P = .0001 for 10 N supination; P = .0001 for 20 N supination) of the injured elbow. CONCLUSIONS: In the highly unstable varus elbow orientation, anconeus tensioning restores the in vitro stability of a combined LCL + CEO-deficient elbow during simulated active motion with the forearm in both pronation and supination. These results may have several clinical implications in managing symptomatic lateral elbow instability.