Annular ligament reconstruction with the superficial head of the brachialis: surgical technique and biomechanical evaluation

Finite Element Analysis of Elbow Joint Stability by Different Flexion Angles of the Annular Ligament

Objective

The injury of the annular ligament can change the stress distribution and affect the stability of the elbow joint, but its biomechanical mechanism is unclear. The present study investigated the biomechanical effects of different flexion angles of the annular ligament on elbow joint stability.

Methods

A cartilage and ligament model was constructed using SolidWorks software according to the magnetic resonance imaging results to simulate the annular ligament during normal, loosened, and ruptured conditions at different buckling angles (0°, 30°, 60°, 90°, and 120°). The fixed muscle strengths were 40 N (F1), 20 N (F2), 20 N (F3), 20 N (F4), and 20 N (F5) for the triceps, biceps, and brachial tendons and the base of the medial collateral ligament and lateral collateral ligament. The different elbow three‐dimensional (3D) finite element models were imported into ABAQUS software to calculate and analyze the load, contact area, contact stress, and stress of the medial collateral ligament of the olecranon cartilage.

Results

The results showed that the stress value of olecranon cartilage increased under different conditions (normal, loosened, and ruptured annular ligament) with elbow extension, and the maximum stress value of olecranon cartilage was 2.91 ± 0.24 MPa when the annular ligament was ruptured. The maximum contact area of olecranon cartilage was 254  mm² with normal annular ligament when the elbow joint was flexed to 30°, while the maximum contact area of loosened and ruptured annular ligament was 283 and 312 mm² at 60° of elbow flexion, and then decreased gradually. The maximum stress of the medial collateral ligament was 6.52 ± 0.23, 11.51 ± 0.78, and 18.74 ± 0.94 MPa under the different conditions, respectively.

Conclusion

When the annular ligament ruptures, it should be reconstructed as much as possible to avoid the elevation of stress on the surface of the medial collateral ligament of the elbow and the annular cartilage, which may cause clinical symptoms.

Technical Note: Arthroscopic Resection of Snapping, Interponating Annular Ligament of the Elbow

The indication for surgical treatment of lateral snapping elbow syndrome is recurrent joint blockage in combination with pain of the affected elbow joint. Different parts of the lateral synovial capsule sleeve complex, including the annular ligament itself, a hypertrophic synovial fold, or meniscus-like soft tissue interposition can lead to painful entrapment. Surgical treatment options can include an arthroscopic or open procedure. The aim of this technical note is to provide a step-by-step illustration of the authors' preferred arthroscopic approach with a comprehensive review of literature on clinical outcome.

The role of the brachialis muscle in elbow stability with collateral ligament injury: A biomechanical investigation

BACKGROUND

The brachialis muscle lies in close anatomic relation to the anterior capsule of the elbow joint. The contribution of the brachialis muscle to elbow stability has not yet been fully investigated. Therefore, the aim of this biomechanical in-vitro study was to analyze its influence on joint stability.

METHODS

Nine fresh frozen cadaveric elbows were evaluated for stability against valgus and varus/posterolateral rotatory forces. Brachialis loading was measured indirectly using strain gauges. Three distinct scenarios were analyzed: A) with intact lateral ulnar and ulnar collateral ligaments B) with a ruptured lateral ulnar collateral ligament C) with ruptured lateral ulnar and ulnar collateral ligaments.

FINDINGS

In all scenarios, an increased strain was observed under posterolateral rotatory/varus forces. The maximum measured strain occurred with elbow flexion of 30° and pronation of the forearm. The strain was significantly higher with dual-ligament rupture (mean - 210.5 μm/m; min. 97.8 μm/m; max. -310 μm/m; SD 107.8 μm/m; p = .034) compared to intact ligaments (mean - 106.9 μm/m; min. -32.51 μm/m, max. -287 μm/m; SD 100.2 μm/m) and single-ligament rupture (mean - 109.5 μm/m; min. - 96.7 μm/m; max - 130.4 μm/m; SD 18.2).

INTERPRETATION

A strain of the brachialis muscle was observed under varus/posterolateral rotatory forces with a pronated forearm and the strain increased significantly in the event of a dual-ligament rupture. This suggests that the brachialis muscle may influence varus/posterolateral rotatory stability of the elbow. Hence, a concomitant tear of the brachialis muscle might result in pronounced instability following simple elbow dislocation.

LEVEL OF EVIDENCE

Basic Science Study, Biomechanics.

[Application of annular ligament reposition and repair via Henry's approach for Monteggia fracture in children]

Objective

To explore the effectiveness of annular ligament reposition and repair via Henry's approach for Monteggia fracture in children.

Methods

A clinical data of 21 children with Monteggia fractures was retrospectively analysed, who underwent open reduction of the radial head and annular ligament reposition and repair via Henry's approach between May 2015 and July 2019. There were 11 boys and 10 girls with an average age of 8 years and 1 month (range, 4 years and 5 months to 14 years and 4 months). The fracture was caused by falling in 17 cases and by falling from height in 4 cases. There were 16 fresh fractures and 5 old fractures. The Monteggia fractures were rated as Bado typeⅠin 14 cases and Bado type Ⅲ in 7 cases. Preoperative MRI examination and intraoperative observation confirmed that the annular ligament was intact. After operation, the fracture healing, elbow range of motion (ROM), and complications were recorded, and the effectiveness was evaluated according to the Mackay's function scoring system.

Results

The incisions healed by first intention after operation, and there was no complication such as radial nerve injury. All children were followed up 12-25 months, with an average of 15 months. No dislocation or subluxation of the radial head occurred after operation. At last follow-up, the ROM of elbow flexion and extension of the children with old fractures increased from (92.6±11.2)° before operation to (123.6±11.6)°, and the ROM of forearm rotation from (96.8±11.8)° to (129.8±5.9)°; the differences between pre- and post-operation were significant ( t=7.672, P=0.002; t=9.487, P=0.001); the ROM of elbow flexion and extension of the children with fresh fractures was 139°-156° (mean, 145°); the ROM of forearm rotation was 158°-168° (mean, 162°). According to Mackay's criteria, 17 cases were excellent and 4 cases were good, with an excellent and good rate of 100%. X-ray film examination showed no nonunion, heterotopic ossification, or loosening of internal fixation after operation. The ulnar fracture and the ulnar osteotomy healed in all cases.

Conclusion

The annular ligament in Monteggia fractures in children is intact. Compared with the reconstruction of the annular ligament, the reposition and repair of the annular ligament via Henry's approach is closer to the original anatomical state of the annular ligament and has the advantages of less trauma and fewer complications.

Isolated Proximal Radioulnar Joint Instability: Anatomy, Clinical Presentation, and Current Treatment Options

Isolated proximal radioulnar joint instability is an uncommon and often challenging problem that may manifest as recurrent instability of the proximal aspect of the radius, usually during forearm pronation and supination. Instability is due to deficiency of the stabilizing structures around the proximal aspect of the radius, and biomechanical studies have highlighted the importance of the annular ligament and the interosseous membrane in both transverse and longitudinal plane stability. Reconstruction of the stabilizing structures around the radial head often is indicated in cases of recurrent instability and includes joint-preserving procedures such as annular ligament reconstruction, proximal ulnar osteotomy, and interosseous membrane reconstruction. Rarely, salvage procedures such as interpositional arthroplasty or 1-bone forearm reconstruction are necessary. A thorough understanding of the anatomic structures that stabilize the proximal aspect of the radius and the complexities of forearm biomechanics is required in order to successfully diagnose and manage this condition.

Neuroanatomical distribution of sensory receptors in the human elbow joint capsule

BACKGROUND

The topographic arrangement of sensory receptors in the human elbow joint capsule is pertinent to their role in the transmission of neural signals. The signals from stimuli in the joint are concisely delivered via afferent pathways to allow recognition of pain and proprioception. Sensory receptors in the elbow joint include mechanoreceptors and free nerve endings acting as nociceptors, although the distribution of each of the structures has not been determined, despite their importance for the integrity of the joint. We therefore aimed to investigate the neuroanatomical distribution and densities of mechanoreceptors and free nerve endings in the capsule of the elbow, at the same time as considering surgical approaches that would result in the minimum insult to them.

METHODS

Four elbow joint capsules were harvested from fresh cadavers. The specimens were carefully separated from adjacent osteoligamentous attachments and the capsular complex was stained with a modified gold chloride method. Evaluations of free nerve endings, and Golgi, Ruffini and Pacinian corpuscles were performed under an inverted light microscope. The number and density of each structure were recorded.

RESULTS

Ruffini corpuscles observed to be the dominant mechanoreceptor type. No Golgi corpuscle was observed. Free nerve endings were found at the highest density at posterodistal sites, whereas mechanoreceptors were most frequent at bony attachment sites.

CONCLUSIONS

A consistent distribution pattern of articular sensory receptors was observed, which allows further understanding of elbow pathology. An awareness of the neuroanatomical distribution of sensory receptors in the elbow joint capsule may allow their preservation during surgical procedures for elbow joint pathology.

Laparoscopic pectopexy: a follow-up cyclic biomechanical analysis determining time to functional stability

INTRODUCTION

Pectopexy, a laparoscopic method for prolapse surgery, showed promising results in previous transient testing by this group. It was shown that a single suture, yielding an ultimate load of 35 N, was equivalent to continuous suturing. This was demonstrated in an in vitro cadaver study. This transient data were used to establish an elastic stress-strain envelope. It was now possible to proceed to dynamic in vitro analysis of this surgical method to establish time to functional stability.

METHODS

Cyclic testing of this fixation method was performed on human female embalmed cadaver (cohort 1) and fresh, non-embalmed cadaver (cohort 2) pelvises. The testing envelope was 5-25 N at a speed of 1 mm/s. 100 load regulated cycles were applied.

RESULTS

100 cycles were completed with each model; no overall system failure occurred. Steady state, i.e., functional stability was reached after 14.5 (± 2.9) cycles for the embalmed group and after 19.1 (± 7.2) cycles for the non-embalmed group. This difference was statistically significant p = 0.00025.

CONCLUSION

This trial showed in an in vitro cyclic testing of the pectopexy method that functional stability may be achieved after no more than 19.1 cycles of load exposure. When remaining within the established load envelope of below 25 N, patients do not need to fear global fixation failure. Testing did demonstrate differences in non-embalmed and embalmed cadaver testing. Embalmed cadaver testing tends to underestimate time to steady state by 26.3%.

Snapping of the annular ligament: a uncommon injury characterised by snapping or locking of the elbow with good surgical outcomes

PURPOSE

Snapping annular ligament is an uncommon cause of lateral elbow pain. The purpose of this case series was to evaluate the clinical presentation and surgical outcomes for snapping annular ligament.

METHODS

Included were 23 patients with snapping annular ligament who received surgical treatment between 2007 and 2016. There were two treatment groups with either resection (arthroscopic or open procedure, n = 15) or open annular ligament reconstruction (n = 8). Patients were assessed with the Mayo Elbow Performance Index and the Oxford Elbow Score. Preoperative and postoperative scores were compared with a paired t test.

RESULTS

Pain was located laterally in nine patients (39.1%), anteriorly in three patients (13.0%), anterolaterally in two patients (8.7%), and diffusely in nine patients (39.1%). In total, 16 patients (69.6%) experienced a snapping sensation and ten patients (43.5%) locking of the elbow. According to the patients' reported outcomes, their symptoms improved significantly after both procedures.

CONCLUSIONS

This is the largest case series in the literature on snapping annular ligament, an uncommon cause of lateral elbow pain. Good treatment results are expected with resection of the interpositioned part of the annular ligament or annular ligament reconstruction.

LEVEL OF EVIDENCE

IV.

Mechanoreceptor profile of the lateral collateral ligament complex in the human elbow

Background

Active restraint for the elbow joint is provided by the soft tissue component, which consists of a musculoligamentous complex. A lesion of the lateral collateral ligament complex (LCLC) is thought to be the primary cause of posterolateral rotatory instability in the elbow. Its role as a protective reflexogenic structure is supported by the existence of ultrastructural mechanoreceptors. The aim of this study was to describe the existence and distribution of LCLC mechanoreceptors in the human elbow joint and to determine their role in providing joint stability.

Methods

Eight LCLCs were harvested from fresh frozen cadaver elbows. Specimens were carefully separated from the lateral epicondyle and ulna. The ligament complex was divided into 7 regions of interest and stained with modified gold chloride. Microscopic evaluation was performed for Golgi, Ruffini, and Pacinian corpuscles. The number, distribution, and density of each structure were recorded.

Results

Golgi, Ruffini, and Pacinian corpuscles were observed in LCLCs, with variable distribution in each region of interest. Ruffini corpuscles showed the highest total mechanoreceptor density. Mechanoreceptor density was higher at bony attachment sites.

Conclusion

The existence and role of each mechanoreceptor defined the purpose of each region of interest. Mechanoreceptors are beneficial for its proprioceptive feature towards a successful elbow ligament reconstruction.