Development of the human elbow joint

Major change in morphology of the talofibular ligaments during fetal development and growth

BACKGROUND AND PURPOSE

Ankle sprain is often attributed to damage of the anterior and posterior talofibular ligaments (ATFL, PTFL). We compared the morphology of these ligaments in fetuses of different gestational ages (GAs) with the horizontal configuration in adults.

MATERIALS AND METHODS

Histological sections of unilateral ankles were examined in 22 fetuses, 10 at GA of 9-12 weeks and 12 at GA of 26-39 weeks.

RESULTS

At a GA of 9 to 10 weeks, the ATFL and PTFL consisted of horizontally running straight fibers. The initial ATFL appeared as a thickening of the capsule of the talocrural joint, although the initial PTFL was distant from this joint. Until a GA of 12 weeks, the talus and fibula were separated by an expanding joint cavity. Thus, the initial horizontal ligaments were "pulled" in a distal direction. The distal parts of the ligaments consisted of thin collagenous fibers that had an irregular array, whereas the short proximal parts had thick fibers and a horizontal array. In near-term fetuses, the ligaments contained no horizontal fibers. The ATFL had a wavy course around the thick synovial fold, and was exposed to the joint cavity along the entire course; the distal part was thinner than the proximal part. The PTFL was bulky and consisted of fibers with an irregular array. Therefore, the morphology in a near-term fetus was quite different from that in adults.

CONCLUSION

The horizontal and straight composite ankle fibers in adults apparently result from postnatal reconstruction, depending on mechanical demand.

The elbow plica: a systematic review of terminology and characteristics

BACKGROUND

There has been a lack of evidence regarding the structure of the elbow plica, or synovial fold. Inconsistency remains regarding the correct terminology, prevalence, and investigation used to understand this anatomic structure.

METHODS

For this systematic review, we searched the PubMed, Ovid-MEDLINE, Cochrane, Google Scholar, and Embase databases using keywords as well as medical subject headings for English-language studies. We conducted a systematic review using the Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines.

RESULTS

We included 27 articles in this review. "Plica" was the most commonly used terminology (33%). The prevalence of plicae in asymptomatic and symptomatic patients was 77% and 97%, respectively. Provocative factors were sporting activities (57%), including those performed by professional athletes, and heavy labor (43%). Lateral elbow pain represented the most common symptom (49%). Magnetic resonance imaging was the most commonly used diagnostic modality (64%). On the magnetic resonance imaging scans of symptomatic patients, the most common location of the plica was the posterolateral region (54%) and its thickness was a minimum of 3 mm. In 2 studies that included symptomatic patients, the plica was found to cover more than one-third of the radial head.

CONCLUSION

Plicae are prevalent in both asymptomatic and symptomatic patients. Consideration of the pathologies associated with an elbow plica helped identify the following: (1) its thickness is >3 mm and (2) its location is in the posterolateral aspect and/or it covers more than one-third of the radial head quadrant.

Systematic Review of the Surgical Outcomes of Elbow Plicae

Background:

Surgical resection is usually required for symptomatic elbow plicae that have failed nonoperative therapy. However, evidence of surgical outcomes has not been presented.

Purpose:

To review the surgical outcomes for the treatment of synovial plicae in the radiocapitellar joint.

Study Design:

Systematic review; Level of evidence, 4.

Methods:

We searched the PubMed, Ovid/MEDLINE, Cochrane Library, Google Scholar, and Embase databases using keywords as well as Medical Subject Headings terms and Emtree ([(elbow OR humeroradial joint OR radiohumeral joint) AND (meniscus OR plica)] OR snapping elbow OR snapping triceps OR synovial fold syndrome OR synovial fringe) for English-language studies. We conducted a systematic review using PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines.

Results:

A total of 14 articles comprising four level 5 and ten level 4 studies were identified, including 279 patients (284 elbows). The triggering factors reported for 58 patients were heavy labor (29 patients; 50.0%), sporting activities (17 patients; 29.3%), and nonspecific trauma (12 patients; 20.7%). Overall, 92 patients (33.0%) were administered a steroid injection before surgery. Arthroscopic plica resection was performed in 266 patients (95.3%). Intraoperatively, plicae were mostly found in the posterior (44.0%) and posterolateral (28.6%) sites, and chondromalacia of the radial head was observed in 25 patients (9.2%). Of the reported surgical outcomes, 67.7% showed a resolution of symptoms. However, 9.3% of patients had residual symptoms, which were likely associated with pre-existing radial head chondromalacia. The complication rate was reported as 1.8%.

Conclusion:

Symptomatic elbow plicae were mostly treated arthroscopically, with most of the results being favorable. Pre-existing chondromalacia and the underestimation of concomitant intra-articular abnormalities may yield an inferior outcome.

Arthroscopic Modified Bosworth Procedure for Refractory Lateral Elbow Pain With Radiocapitellar Joint Snapping

Background:

Radiocapitellar joint snapping due to the presence of synovial plica has been described as a contributory intra-articular pathology of lateral epicondylitis (LE).

Hypothesis:

The arthroscopic modified Bosworth technique can provide a safe and favorable outcome for refractory LE with radiocapitellar snapping.

Study Design:

Case series; Level of evidence, 4.

Methods:

Patients treated with the arthroscopic modified Bosworth procedure for refractory LE with radiocapitellar joint snapping were included in this study. The sequential surgical procedures included excision of the upper portion of the anterolateral annular ligament, removal of the synovial plicae, and release of the extensor carpi radialis brevis for all patients. Clinical outcomes were measured at a minimum 1-year follow-up.

Results:

A total of 22 patients with a mean ± SD age of 51.2 ± 10.4 years were included in this study. The mean follow-up was 29.4 ± 7.7 months (range, 21-42 months). The overall visual analog scale score (from preoperative to final follow-up) was 7.5 ± 1.2 vs 2.5 ± 1.8 (P < .001); flexion-extension motion arc was 133.8° ± 11.2° vs 146.4° ± 7.1° (P = .001); pronation-supination motion arc was 101.8° ± 9.2° vs 141.7° ± 10.2° (P = .001); Disabilities of the Arm, Shoulder and Hand score was 54.5 ± 13.2 vs 3.6 ± 4.1 (P < .001); and Mayo Elbow Performance Score was 51.9 ± 12.2 vs 84.3 ± 10.3 (P < .001).

Conclusion:

Radiocapitellar joint snapping may coexist with LE as a disease spectrum. The arthroscopic modified Bosworth technique provides safe and favorable outcomes for patients with refractory LE associated with radiocapitellar joint snapping.

A temporary disc-like structure at the median atlanto-axial joint in human fetuses

During observations of mid-term and late-stage fetuses, we found a joint disk-like structure at the anterior component of the median atlanto-axial joint. At mid-term, the disk-like structure was thick (0.1–0.15 mm) relative to the sizes of bones surrounding the joint. However, it did not completely separate the joint cavity, and was absent in the inferior and/or central part of the cavity. This morphology was similar to the so-called fibroadipose meniscoid of the lumbar zygapophysial joint that is usually seen in adults. In mid-term fetuses, there was evidence suggesting that a mesenchymal tissue plate was separated from a roof of the joint cavity. In late-stage fetuses, the thickness (less than 0.15 mm) was usually the same as, or less than that at mid-term, and the disk-like structure was often flexed, folded and fragmented. Therefore, in contrast to the zygapophysial meniscoid as a result of aging, the present disk-like structure was most likely a temporary product during the cavitation process. It seemed to be degenerated in late-stage fetuses and possibly also in newborns. Anomalies at the craniocervical junction such as Chiari malformations might accompany this disk-like structure at the median atlanto-axial joint even in childhood.

Prominent synovial plicae in radiocapitellar joints as a potential cause of lateral elbow pain: clinico-radiologic correlation

BACKGROUND

Thickened synovial plicae in the radiocapitellar joint have been reported as a cause of lateral elbow pain. However, few reports regarding diagnosis based on detailed physical examination and magnetic resonance imaging (MRI) findings are available. The aims of this study were to characterize the clinical manifestations of this syndrome and to investigate the clinical outcomes of arthroscopic surgery.

METHODS

We analyzed 20 patients who received a diagnosis of plica syndrome and underwent arthroscopic débridement between 2006 and 2011. The diagnosis was based on physical examination and MRI findings. Elbow symptoms were assessed using a visual analog scale for pain; the Mayo Elbow Performance Index; and the Disabilities of the Arm, Shoulder and Hand score at a minimum of 2 years after surgery. The thickness of plicae on MRI was compared with the normal data in the literature.

RESULTS

Plicae were located on the anterior side in 1 patient, on the posterior side in 15, and on both sides in 4. Radiocapitellar joint tenderness and pain with terminal extension were observed in 65% of patients. MRI showed enlarged plicae consistent with intraoperative findings. The mean plica thickness on MRI was 3.7 ± 1.0 mm, which was significantly thicker than the normal value. The mean lengths (mediolateral length, 9.4 ± 1.6 mm; anteroposterior length, 8.2 ± 1.7 mm) were also greater than the normal values. The visual analog scale score for pain decreased from 6.3 to 1.0 after surgery. The Mayo Elbow Performance Index and Disabilities of the Arm, Shoulder and Hand scores improved from 66 to 89 and from 26 to 14, respectively.

CONCLUSIONS

Specific findings of the physical examination and MRI provide clues for the diagnosis of plica syndrome. Painful symptoms were successfully relieved after arthroscopic débridement.

[The bare area of the proximal ulna : An anatomical study on optimizing olecranon osteotomy]

BACKGROUND

Olecranon osteotomy is an established approach for the treatment of distal humerus fractures. It should be performed through the bare area of the proximal ulna to avoid iatrogenic cartilage lesions.

OBJECTIVES

The goal of this study was to analyze the anatomy of the proximal ulna with regard to the bare area and, thereby, to optimize the hitting area of the bare area when performing olecranon osteotomy.

MATERIALS AND METHODS

The bare areas of 30 embalmed forearm specimens were marked with a radiopaque wire and visualized three-dimensionally with a mobile C‑arm. By means of 3D reconstructions of the data sets, the following measurements were obtained: height of the bare area; span of the bare area-hitting area in transverse osteotomy; ideal angle for olecranon osteotomy to maximize the hitting area of the bare area; distance of the posterior olecranon tip to the entry point of the transverse osteotomy and the ideal osteotomy.

RESULTS

The height of the bare area was 4.92 ± 0.81 mm. The hitting area of the transverse osteotomy averaged 3.73 ± 0.89 mm. The "ideal" angle for olecranon osteotomy was 30.7° ± 4.19°. The distance of the posterior olecranon tip to the entry point was 14.08 ± 2.75 mm for the transverse osteotomy and 24.21 ± 3.15 mm for the ideal osteotomy. The hitting area of the bare area in the ideal osteotomy was enhanced significantly when compared to the transverse osteotomy (p < 0.0001).

CONCLUSIONS

This study provides guide values for correct osteotomy of the olecranon. Moreover, a 30° angulation of the osteotomy can significantly increase the hitting area of the bare area.

CT arthrography and anatomical correlation of the bare area of the ulnar trochlear fossa: a risk of misdiagnosis of cartilage ulcerations

AIMS

There is a variable bare area on the ulnar trochlear fossa that may be somehow interpreted as a cartilage defect. We aimed to correlate radiological images and dissections of this bare spot with CT arthrography imaging.

MATERIALS AND METHODS

We conducted a double study that included 10 unpaired fresh-frozen human cadaveric elbows (CT arthrography + dissection) and 40 CT arthrography of patients to investigate the 3-D architecture of the trochlear fossa of the ulna. Positioning, shape and measurements of the bare spot of each ulna were measured and correlated. A total of 40 were analyzed with this protocol of measurements to validate the anatomical findings.

RESULTS

The bare spot area is located 15.8 mm from the tip of the olecranon and 13.8 mm from the coronoid process (mean values). This area measures 4.1 mm in cranio-caudal plane, 2.2 mm in transversal plane. This area is located above a small subchondral tubercle that measures 1.0 mm in antero-posterior axis. No significant difference has been found between left and right elbow regarding its positioning and shape. A significant difference has been found between genders regarding the positioning of this area but not according to its shape.

CONCLUSION

The ulnar trochlear notch has a small area without cartilage. This bare area is located at the site of fusion of the different ossification center of the proximal ulna. It should not be interpreted as a chondral lesion. The existence of a subchondral tubercle clearly indicates that this uncovered zone is normal. Radiologist should consider this when interpreting elbow CT arthrography.

Influence of developing ligaments on the muscles in contact with them: a study of the annular ligament of the radius and the sacrospinous ligament in mid-term human fetuses

The supinator muscle originates from the annular ligament of the radius, and the muscle fibers and ligament take a similar winding course. Likewise, the coccygeus muscle and the sacrospinous ligament are attached together, and show a similar fiber orientation. During dissection of adult cadavers for our educational curriculum, we had the impression that these ligaments grow in combination with degeneration of parts of the muscles. In histological sections of 25 human fetuses at 10-32 weeks of gestation, we found that the proximal parts of the supinator muscle were embedded in collagenous tissue when the developing annular ligament of the radius joined the thick intermuscular connecting band extending between the extensor carpi radialis and anconeus muscles at 18-22 weeks of gestation, and the anterior parts of the coccygeus muscle were surrounded by collagenous tissue when the intramuscular tendon became the sacrospinous ligament at 28-32 weeks. Parts of these two muscles each seemed to provide a mold for the ligament, and finally became involved with it. This may be the first report to indicate that a growing ligament has potential to injure parts of the "mother muscle," and that this process may be involved in the initial development of the ligament.

Elbow MR imaging findings in patients with synovial fringe syndrome

OBJECTIVE

To describe imaging findings in patients with synovial fringe (SF) syndrome of the elbow and to compare with a control population.

MATERIALS AND METHODS

Nine patients (5 men, 4 women) whose mean age was 35.7 years were diagnosed with SF syndrome and had undergone preoperative elbow MRI. The radiohumeral (RH) plica was assessed for thickness, cross-sectional area, coverage of one third or more of the radial head, blunting of the free edge, and T2 signal intensity abnormality. Other abnormalities of the RH joint were also assessed, including adjacent articular cartilage defects, subcortical bone marrow signal abnormality in the capitellum, and synovitis. Results were compared with 15 control patients who were asymptomatic laterally and posteriorly.

RESULTS

Mean thickness and cross-sectional area of the RH plica were 1.8 mm and 19.4 mm(2) respectively in controls, compared with 2.5 mm and 21.9 mm(2) respectively in symptomatic patients. No statistically significant differences in the distribution of the mean thickness or cross-sectional area of the RH plica were found between the two groups. However, 67% of SF syndrome patients had a RH plica thickness greater than 2.6 mm compared with only 13% of controls (p = 0.021). Other abnormalities of the RH plica occurred more frequently in patients with SF syndrome compared with controls, but were not statistically significant.

CONCLUSION

In patients presenting with posterolateral pain or mechanical symptoms in the elbow, RH plica thickness greater than 2.6 mm on elbow MRI examinations may help identify patients with SF syndrome.

Regeneration of the elbow joint in the developing chick embryo recapitulates development

Synovial joints are among the most important structures that give us complex motor abilities as humans. Degenerative joint diseases, such as arthritis, cause loss of normal joint functioning and affect over 40 million people in the USA and approximately 350 million people worldwide. Therapies based on regenerative medicine hold the promise of effectively repairing or replacing damaged joints permanently. Here, for the first time, we introduce a model for synovial joint regeneration utilizing the chick embryo. In this model, a block of tissue that contains the prospective elbow is excised, leaving a window with strips of anterior and posterior tissue intact (window excision, WE). In contrast, we also slice out the same area containing the elbow and the distal piece of the limb is pinned back onto the stump (slice excision, SE). Interestingly, when the elbow is removed via WE, regeneration of the joint takes place, whereas the elbow joint does not regenerate following SE. In order to investigate whether the regeneration response recapitulates the developmental program of forming joints, we used GDF-5 and Autotaxin (Atx) as joint tissue specific markers, and Sox-9 and Col-9 as cartilage markers for in situ hybridization on sections at different time points after WE and SE surgeries. Re-expression of GDF-5 and Atx is observed in the WE samples by 60h after surgery. In contrast, the majority of the samples that underwent SE surgery did not express GDF-5 and Atx. Also, in SE fusion of cartilage elements takes place and the joint interzone does not form. This is indicated by continuous Col-9 expression in SE limbs, whereas Col-9 is downregulated at the joint interzone in the regenerating WE samples. This order and pattern of gene expression observed in regenerates is similar to the development of a joint suggesting that regeneration recapitulates development at the molecular level. This model defines some of the conditions required for inducing joint regeneration in an otherwise nonregenerating environment. This knowledge can be useful for designing new therapeutic approaches for joint loss or for conditions affecting joint integrity in humans.

Usefulness of MRI for diagnosis of painful snapping elbow

Painful snapping of the elbows is rare. We report on a 12-year-old boy with a painful snap in both elbows. High-resolution magnetic resonance imaging of the elbow using microscopy coils detected a synovial fold interposed in each humeroradial joint and was very helpful in establishing the cause of symptoms. Resection of the synovial folds was performed with subsequent relief of symptoms.