Athletic injuries of the extensor carpi ulnaris subsheath: MRI findings and utility of gadolinium-enhanced fat-saturated T1-weighted sequences with wrist pronation and supination

An Analysis of Extensor Carpi Ulnaris Groove Morphology and Tendon Instability

BACKGROUND

The extensor carpi ulnaris (ECU) tendon has a distinct subsheath at the distal ulna. Symptomatic tears of this subsheath and subluxation of the ECU tendon often require reconstruction. We sought to determine the anatomical constraints of the ECU subsheath.

METHODS

The ECU subsheath was exposed on 12 fresh-frozen upper extremities. The tip of the ulnar styloid, the distal ulnar joint surface, and the proximal extent of the distal radio-ulnar joint were identified and dimensions measured. Subluxation of the tendon was then assessed with and without an intact subsheath in 9 specimens. The travel of the tendon was measured in pronation through supination and flexion before and after sectioning of the subsheath.

RESULTS

The ECU subsheath is 8.9 mm (standard deviation [SD] = 0.8 mm) wide proximally and 9.0 mm (SD = 1.2 mm) distally. The distal ulnar insertion is 0.5 mm (SD = 0.8 mm) proximal to the tip of the styloid, and stretches 10.2 mm (SD = 2.7 mm) proximally. From maximum pronation to maximum supination and flexion, the ECU tendon traveled 3.32 mm (SD = 4.24) medially when the subsheath was intact and 5.42 mm (SD = 5.0 mm) after sectioning. The maximum depth of the ulnar groove was 2.5 mm (1.59-3.56 mm). There was no significant association between changes in ECU subluxation and the depth of the ECU groove (Spearman's rho = 0.25).

CONCLUSION

The ECU subsheath is roughly 1 cm square stretching proximally from the ulnar styloid. ECU groove depth is not a significant independent predictor of tendon subluxation.

Interdisciplinary consensus statements on imaging of DRUJ instability and TFCC injuries

OBJECTIVES

The purpose of this agreement was to establish evidence-based consensus statements on imaging of distal radioulnar joint (DRUJ) instability and triangular fibrocartilage complex (TFCC) injuries by an expert group using the Delphi technique.

METHODS

Nineteen hand surgeons developed a preliminary list of questions on DRUJ instability and TFCC injuries. Radiologists created statements based on the literature and the authors' clinical experience. Questions and statements were revised during three iterative Delphi rounds. Delphi panelists consisted of twenty-seven musculoskeletal radiologists. The panelists scored their degree of agreement to each statement on an 11-item numeric scale. Scores of "0," "5," and "10" reflected complete disagreement, indeterminate agreement, and complete agreement, respectively. Group consensus was defined as a score of "8" or higher for 80% or more of the panelists.

RESULTS

Three of fourteen statements achieved group consensus in the first Delphi round and ten statements achieved group consensus in the second Delphi round. The third and final Delphi round was limited to the one question that did not achieve group consensus in the previous rounds.

CONCLUSIONS

Delphi-based agreements suggest that CT with static axial slices in neutral rotation, pronation, and supination is the most useful and accurate imaging technique for the work-up of DRUJ instability. MRI is the most valuable technique in the diagnosis of TFCC lesions. The main indication for MR arthrography and CT arthrography are Palmer 1B foveal lesions of the TFCC.

CLINICAL RELEVANCE STATEMENT

MRI is the method of choice for assessing TFCC lesions, with higher accuracy for central than peripheral abnormalities. The main indication for MR arthrography is the evaluation of TFCC foveal insertion lesions and peripheral non-Palmer injuries.

KEY POINTS

• Conventional radiography should be the initial imaging technique in the assessment of DRUJ instability. CT with static axial slices in neutral rotation, pronation, and supination is the most accurate method for evaluating DRUJ instability. • MRI is the most useful technique in diagnosing soft-tissue injuries causing DRUJ instability, especially TFCC lesions. • The main indications for MR arthrography and CT arthrography are foveal lesions of the TFCC.

Advantages of the Use of Axial Traction Magnetic Resonance Imaging (MRI) of the Shoulder in Patients with Suspected Rota-Tor Cuff Tears: An Exploratory Pilot Study

Magnetic Resonance Imaging (MRI) with axial traction is a tool for the assessment of musculoskeletal pathology. Previous reports have demonstrated a better distribution of intra-articular contrast material. No investigations were performed to evaluate glenohumeral joint axial traction MRI in patients with suspected rotator cuff tears. This study aims to assess the morphological changes and the potential advantage of glenohumeral joint axial traction MRI without intra-articular contrast administration in patients with suspected rotator cuff tears. Eleven patients with clinical suspicion of rotator cuff tears underwent a shoulder MRI scan with and without axial traction. PD weighted images with SPAIR fat saturation technique and T1 weighted images with TSE technique were acquired in the oblique coronal, oblique sagittal and axial planes. Axial traction allowed a significant widening of the subacromial space (11.1 ± 1.5 mm vs. 11.3 ± 1.8 mm; p = 0.001) and inferior glenohumeral space (8.6 ± 3.8 mm vs. 8.9 ± 2.8 mm; p = 0.029). With axial traction, there was a significant decrease in measurements of the acromial angle (8.3 ± 10.8° vs. 6.4 ± 9.8°; p < 0.001) and gleno-acromial angle (81 ± 12.8° vs. 80.7 ± 11.5°; p = 0.020). Our investigation demonstrates for the first time significant morphological changes in the shoulder of patients with suspected rotator cuff tears who underwent a glenohumeral joint axial traction MRI.

Radially Based Extensor Retinacular Sling Reconstruction for Extensor Carpi Ulnaris Subsheath Injuries in Elite Athletes

BACKGROUND

Extensor carpi ulnaris (ECU) subsheath injuries are an increasingly recognized cause of ulnar-sided wrist pain in elite athletes. There is a lack of surgical outcome data in elite athletes, and unique considerations exist for these patients.

METHODS

We performed a retrospective review of our hand center experience of 14 elite professional or collegiate athletes who prospectively underwent radially based extensor retinacular sling ECU subsheath reconstruction by 3 hand surgery-fellowship-trained surgeons between April 2011 and April 2021. Clinical, magnetic resonance imaging (MRI), and intraoperative findings were cataloged. Subgroup analyses of elite hockey players and acute subsheath injuries were also conducted. Statistical analysis was performed via a 2-tailed paired t test.

RESULTS

Mean age at the time of surgery was 21.3 years (range, 18-34). Mean time from symptom onset to surgery was 102.1 ± 110.7 days. All 14 patients underwent preoperative MRI. Five patients (35.7%) had intrinsic ECU tendinopathy, 9 patients (64.3%) had ECU tenosynovitis, 6 patients (42.9%) had triangular fibrocartilage complex tears, and 9 patients (64.3%) had ulnocarpal synovitis. Mean postoperative pain on a Visual Analog Scale was 0.25 ± 0.43. Grip strength (P = .001), wrist flexion-extension (P = .037), and pronosupination arcs (P = .093) showed excellent recovery postoperatively. Mean time to unrestricted return to sports was 92.5 ± 21.0 days. There were no complications. Subgroup analyses found similar functional improvement and characterized injury patterns.

CONCLUSIONS

Overall, our findings suggest surgical management of ECU subsheath injuries is a viable option in both acute and chronic settings in elite athletes and may be favorable compared with nonoperative management.

Radially Based Extensor Retinacular Sling Reconstruction for Extensor Carpi Ulnaris Subsheath Injuries

Purpose

Extensor carpi ulnaris (ECU) subsheath injuries result in ulnar-sided wrist pain and often present concurrently with intrinsic ECU pathology and ulnocarpal compartment injuries. There is a lack of surgical outcome data despite the variety of described ECU subsheath pathologies and reconstructive strategies.

Methods

We retrospectively reviewed our hand-center experience of 33 patients who prospectively underwent radially based extensor retinacular sling ECU subsheath reconstruction by 4 hand surgery-fellowship-trained surgeons between April 2010 and April 2021. Preoperative clinical and magnetic resonance imaging findings, along with intraoperative findings, were cataloged. Statistical analysis was conducted via a 2-tailed paired t test.

Results

The median age at the time of surgery was 44 years (range, 18-63 years). Twenty (60.6%) patients underwent reconstruction on their dominant wrist. The median time between symptom onset and surgery was 6.5 months (range, 4 days-16.1 years). Eight (18%) patients were collegiate-level or professional athletes. Ten (30.3%) patients had frank ECU snapping on the preoperative examination with no recurrence or apprehension on the postoperative examination. All 33 patients underwent a preoperative magnetic resonance imaging. Fifteen (45.4%) patients had intrinsic ECU tendinopathy, 19 (57.6%) patients had ECU tenosynovitis, 18 (54.5%) patients had triangular fibrocartilage complex tears, 20 (60.6%) patients had ulnocarpal synovitis, and 2 (6.1%) patients had lunotriquetral interosseous ligament tears. The mean postoperative pain on a visual analog scale was 0.39 ± 0.55. Grip strength, wrist flexion-extension, and pronosupination arcs (P < .05) showed excellent recovery after surgery. The mean time to unrestricted return to sports was 97.3 ± 19.7 days for the athletes in this study. There were no major complications.

Conclusions

Radially based extensor retinacular sling ECU subsheath reconstruction resulted in satisfactory improvements in range of motion and grip strength. Although the mean improvements in these parameters were statistically significant, the clinical significance of these postoperative improvements remains to be defined.

Type of study/level of evidence

Therapeutic, Level IV.

Tendons and Tendon Sheaths of the Hand - An Update on MRI

BACKGROUND

 The tendons of the hand run in close proximity to each other and within retinacular tunnels adjacent to articular joints, while forming intersections in characteristic locations. The enclosing tendon sheaths are often sites of systemic or infectious inflammation.

METHOD

 This review article outlines the different entities of tendon and tendon sheath pathology and their manifestation in the hands. Diagnostic findings in tendon and tendon sheath disorders are illustrated using MRI imaging and discussed in context with the current literature.

RESULTS AND CONCLUSION

 Overuse may cause stenosis in the fibrous outer layer of the retinacula and the A1 annular ligaments as well as tendinosis. In contrast, proliferative tenosynovitis is a disease of the synovial inner layer of the tendon sheath with tendon infiltration and tendinitis. Pyogenic tenosynovitis favors the flexor compartments. Because of the narrow spaces in the hand, a high-resolution MRI technique must be used.

KEY POINTS

  · Diseases of the tendons and tendon sheaths may have a mechanical, degenerative, metabolic, systemic inflammatory, or infectious etiology.. · Fibrous tunnels and bony prominences in close proximity to crossing tendons predispose to mechanical tendon irritation at typical sites of the hand.. · Stenosing tenovaginitis occurs in the fibrous layer of the extensor retinaculum or the A1 annular pulleys. The most frequent manifestations are the "trigger finger" and de Quervain disease.. · Proliferative tenosynovitis affects the synovial layer of the tendon sheaths before infiltrating the tendons. The classic representative is rheumatoid arthritis..

CITATION FORMAT

· Schmitt R, Hesse N, Grunz JP. Tendons and Tendon Sheaths of the Hand - An Update on MRI. Fortschr Röntgenstr 2022; DOI: 10.1055/a-1826-1007.

Advanced Imaging of Ulnar Wrist Pain

Ulnar-sided wrist pain can be a diagnostic challenge for clinicians and radiologists. The ulnar wrist has complex morphology and is composed of many small bone and soft tissue structures. Within these structures, a wide variety of pathologic conditions can occur. To successfully diagnose and treat these pathologic conditions, clinicians and radiologists must have a strong understanding of the advanced imaging techniques available to them. In this review, the authors present a brief review of the normal ulnar wrist anatomy, discuss the differential diagnosis of ulnar-sided wrist pain, and examine the indications for different advanced imaging modalities.

Is it really safe to evaluate symptomatic extensor carpi ulnaris tendon instability by magnetic resonance imaging (MRI)?

The extensor carpi ulnaris (ECU) tendon is in the sixth extensor compartment of the wrist and is isolated from other tendons by a different sheath. Extensor carpi ulnaris pathologies are characterized by pain locally localized to the wrist ulnar side. Outpatient records and wrist MRI (magnetic resonance imaging) tests were retrospectively scanned between January 2018 and July 2019. By examining the anamnesis and examination notes of the patients in the outpatient clinic records, patients with wrist ulnar side pain, pain or sensitivity on the ulnar styloid and provocation test (synergy) were assigned to the first study group (Group 1).The second study group was composed of patients who underwent wrist MR for the diagnosis or differential diagnosis of a synovial cyst around the wrist, without ulnar side pain (Group 2).While evaluating MR images in the axial plane, the depth and width of the ulnar groove, thickness of the ECU tendon were measured. The position of the ECU tendon relative to the ulnar groove and the forearm rotation during the shooting were recorded.105 cases evaluated, there were 41 cases in the symptomatic subgroup and 64 cases in the asymptomatic subgroup. Among all patients, the mean patient age was 38.05.In the evaluation according to whether cases were symptomatic or not, there was no significant relationship between being symptomatic and the degree of instability and MR withdrawal position. Our study suggests that ECU instability in MR is not a specific condition, and detection of MR in instability may not be associated with a patient’s symptoms.

Ulnar-Sided Wrist Pain in the Athlete: Sport-Specific Demands, Clinical Presentation, and Management Options

ABSTRACT

Ulnar-sided wrist injuries are common in sports that require repeated pronosupination, wrist radial/ulnar deviation, axial loading, and gripping equipment. Common anatomic structures affected include the triangular fibrocartilage complex, extensor carpi ulnaris tendon, distal radioulnar and ulnocarpal joints, and hamate bone. Presenting symptoms include pain with activity, swelling, possible snapping or clicking, and reproduction of symptoms with provocative maneuvers. Imaging may confirm or rule out pathologies, but abnormal findings also may present in asymptomatic athletes. Initial treatment is usually nonoperative with splinting, load management, activity modification, strengthening the components of the kinetic chain of the particular sport, and pain management. Surgery is usually indicated in ulnar-wrist pain pathology such as hook of hamate fractures and required in associated instability. Future research should address specific treatment and rehabilitation protocols, emphasizing the complete kinetic chain along with the injured wrist.

Tennis overuse injuries in the upper extremity

OBJECTIVE

Tennis is a popular sport with high levels of participation. This article aims to describe how upper extremity overuse injuries occur in relation to tennis biomechanics and to review their imaging characteristics and implications for management. In particular, we will review the imaging patterns of internal impingement, scapular dyskinesis, lateral and medial epicondylitis, ulnar collateral ligament insufficiency, valgus extension overload, capitellar osteochondritis dissecans, extensor carpi ulnaris tendinosis and instability, tenosynovitis, triangular fibrocartilage complex injuries, and carpal stress injuries.

CONCLUSION

Tennis is a complex and physically demanding sport with a wide range of associated injuries. Repetitive overloading commonly leads to injuries of the upper extremity. An understanding of the underlying mechanisms of injury and knowledge of these injury patterns will aid the radiologist in generating the correct diagnosis in both the professional and recreational tennis athlete.

An Evidence-Based Review of Overuse Wrist Injuries in Athletes

Overuse wrist injuries are a common problem in athletes and can be related to tendinopathies or osteoarticular pathology. Fortunately, athletes rarely miss time from their sport due to these conditions because many can be treated nonoperatively. For refractory cases, there often is a curative surgical procedure that can be done during the off-season.

Do magnetic resonance imaging abnormalities of the non-dominant wrist correlate with ulnar-sided wrist pain in elite tennis players?

OBJECTIVE

Ulnar-sided injuries of the non-dominant wrist are common in elite tennis players that use the double-handed backhand technique. This study aimed to define the relationship between ulnar-sided wrist pain in symptomatic and asymptomatic elite tennis players, and the presence of abnormalities on magnetic resonance imaging (MRI).

MATERIALS AND METHODS

Fourteen symptomatic tennis players, 14 asymptomatic tennis players, and 12 healthy controls who did not play tennis, were analyzed prospectively, after undergoing MRI of their non-dominant wrist. Five anatomical regions were analyzed, thought to relate to ulnar-sided wrist pain. These consisted of the triangular fibrocartilage complex (TFCC), ulnar collateral ligament (UCL), extensor carpi ulnaris tendon (ECU), osseous-articular structures, and ganglia. Images were independently reviewed by two blinded musculoskeletal radiologists.

RESULTS

Non-dominant, ulnar-sided, wrist pain in elite tennis players was not statistically significantly associated with an increased number of MRI abnormalities when compared with asymptomatic tennis players (p > 0.05). However, some evidence of statistical association was seen with an increased prevalence of ECU tendon abnormalities (OR = 8.0, 95% CI = (0.74, 20.00), p = 0.07). A statistically significant increase in MRI abnormalities of osseous structures (OR = 15.1, 95% CI = (1.56, 656.05), p = 0.02) and the dorsal radioulnar ligament (DRUL) (OR = 12.5, 95% CI = (2.15, 111.11), p = 0.03), was observed in symptomatic players compared with controls.

CONCLUSIONS

Non-dominant, ulnar-sided, wrist pain in a subgroup of elite tennis players using a double-handed backhand technique is not associated with a statistically significant increased prevalence of MRI abnormalities when compared with asymptomatic tennis players, other than some evidence of statistical association with ECU tendon abnormalities. Therefore, significance of MRI abnormalities should be interpreted in the context of clinical findings.

MRI does not effectively diagnose ulnar-sided wrist pain in elite tennis players

OBJECTIVES

Ulnar-sided injuries of the non-dominant wrist are common in elite tennis players using a double-handed backhand technique. This study investigated the radiological changes of the non-dominant wrist in elite symptomatic and asymptomatic players using this technique as well as healthy controls. We compared clinical findings to radiological abnormalities.

DESIGN

Cross-sectional design with blinded radiological assessment, and contemporaneous clinical assessment of symptomatic players.

METHODS

Magnetic resonance images (MRI) of wrists related to non-dominant ulnar-sided pain, were taken in 14 symptomatic tennis players, 14 asymptomatic tennis players, and 12 healthy controls which were then independently reviewed for abnormalities by blinded radiologists. Total abnormalities and global between-group differences in the triangular fibrocartilage complex (TFC), ulnar collateral ligament (UCL), extensor carpi ulnaris (ECU) and supporting structures, osseous-articular lesions and ganglia were assessed. These were then compared to clinical examinations of the symptomatic players to assess agreement.

RESULTS

Symptomatic players reported a mean 3.64 abnormalities, being exactly 1 abnormality greater than asymptomatic players (2.64) and controls (2.50), suggesting similar asymptomatic lesions in all three groups. Players with pain reported significantly more osseous-articular lesions, ECU tendon and dorsal radio-ulnar ligament abnormalities, while changes to the UCL may reflect an isolated problem in specific wrists. There were no between-group differences in the presence of ganglia, most TFC structures nor ECU subsheath tear and subluxation.

CONCLUSIONS

Clinicians should carefully consider radiological changes alongside their clinical diagnosis of non-dominant wrist pain in tennis players due to possible tennis-related changes and/or asymptomatic findings.

Radiographic/MR Imaging Correlation of the Wrist

In this review article, the authors discuss the imaging features of the most common pathologic conditions of the wrist by putting the emphasis on radiographic and MR imaging correlations. A topographic approach based on the 3 functional columns of the wrist (radial, central, and ulnar) serves as a framework. The pathologic conditions are classified, based on the structures involved, as fractures, ligament injuries, arthropathies, bone abnormalities, and tendinopathies. The authors describe and evaluate classic radiographic signs and explain how they correlate with MR imaging. The advantages and limitations of each technique are thoroughly discussed as well as other imaging modalities.

Hand and Wrist Injuries in Tennis Players

PURPOSE OF REVIEW

The purpose of this article is to review common hand and wrist injuries experienced by tennis players.

RECENT FINDINGS

A myriad of different wrist pathologies can be seen in tennis players ranging from metacarpal and carpal stress fractures to triangular fibrocartilage injuries and ulnar impaction. These vary depending upon the nature of the player, stroke mechanics, and time point within the season. A broad differential should guide work-up and management of wrist pain in tennis players.

Mid-term outcome (11-90 months) of the extensor retinaculum flap procedure for extensor carpi ulnaris tendon instability

INTRODUCTION

The aim of our study was the assessment of the mid-term outcome of patients treated with a pediculated extensor retinaculum flap for extensor carpi ulnaris (ECU) tendon subluxation including postoperative tendon stability control.

MATERIALS AND METHODS

Twelve patients treated with an extensor retinaculum flap for symptomatic ECU tendon instability were retrospectively evaluated. Follow-up examinations included functional and radiologic assessment. The range of motion, grip strength, DASH score, PRWE score, Krimmer score and subjective satisfaction were recorded. A rotation-movie MRI was conducted before and after surgery to visualize tendon displacement.

RESULTS

Wrist extension was 65.8° (SD 10.0°), flexion 64.2° (SD 12.2°), radial deviation 15.8° (SD 6.0°), ulnar deviation 32.1° (SD 7.2°), pronation 82.5° (SD 9.4°) and supination 85.0° (SD 9.0°). Mean grip strength was 30.5 kg (SD 8.9 kg). Six patients presented an excellent, four a good, one a fair and one a poor result on the Krimmer score. The DASH and PRWE scores showed a mean of 24.2 (SD 25.1) and 32.2 (SD 29.4) points. MRI showed a dislocation (n = 7) or subluxation (n = 5) of the ECU tendon preoperatively. Five patients showed an unchanged displacement pattern postoperatively.

CONCLUSION

The pediculated extensor retinaculum flap as a treatment for a symptomatic ECU instability shows good to excellent results and a high subjective satisfaction independent of postoperative ECU tendon displacement.

Anatomy and injuries of the pediatric wrist: beyond the basics

Ligamentous injuries of the pediatric wrist, once thought to be relatively uncommon, are increasingly recognized in the context of acute high-energy mechanism trauma and chronic axial loading, including those encountered in both recreational and high-performance competitive sports. Recent advances in MR-based techniques for imaging the pediatric wrist allow for sensitive identification of these often radiographically occult injuries. Detailed knowledge of the intrinsic and supportive extrinsic ligamentous complexes, as well as normal developmental anatomy and congenital variation, are essential to accurately diagnose injuries to these structures. Early identification of ligamentous injury of the pediatric wrist is essential within the conservative treatment culture of modern pediatric orthopedics because treatment of these lesions often necessitates surgery, and outcomes often depend on early and sometimes aggressive intervention. In this article, we review MR arthrogram technique and pediatric wrist anatomy, and correlate appearances on MR and selected ligamentous pathologies of the pediatric wrist.

Intra-articular Fracture of the Distal part of the Triquetrum within the Pisotriquetral Joint: Case Report and Review of Literature

Background

Intra-articular fractures of the distal part of the triquetrum within the pisotriquetral joint are uncommon, and can be associated with tears of the dorsal carpal ligaments, pisiform subluxation and/or FCU dislocation. Their diagnosis is difficult and requires a high clinical suspicion and a proper radiological examination including oblique wrist x-rays, computed tomography and MRI scan. These fractures can be delayed diagnosed due to late presentation thus leading to painful nonunion, persistent instability and late pisotriquetral arthritis.

Case Report

We present a case of a 40-year-old male who complained about ulnarsided wrist pain after a fall on his extended wrist during bicycling. The diagnosis of triquetrum fracture was suspected on clinical examination and confirmed using standard and oblique radiographs and CT scan evaluation. He was immobilized in a short-arm cast for 6 weeks followed by a progressive return to wrist motion and subsequent strengthening for another 5 weeks. He reported complete resolution of pain and excellent wrist motion and function one year after the injury, demonstrating a Mayo score of 100.

Conclusion

Isolated intra-articular fractures of the triquetrum within the pisotriquetral joint are rare injuries and may constitute a subcategory of body fractures other than the dorsal cortical (chip), main body and volar lip avulsion fractures. Early clinical suspicion and proper imagine can lead to a successful outcome.

High-resolution 3-T MRI of the triangular fibrocartilage complex in the wrist: injury pattern and MR features

OBJECTIVES

To investigate if using high-resolution 3-T MRI can identify additional injuries of the triangular fibrocartilage complex (TFCC) beyond the Palmer classification.

MATERIALS AND METHODS

Eighty-six patients with surgically proven TFCC injury were included in this study. All patients underwent high-resolution 3-T MRI of the injured wrist. The MR imaging features of TFCC were analyzed according to the Palmer classification.

RESULTS

According to the Palmer classification, 69 patients could be classified as having Palmer injuries (52 had traumatic tears and 17 had degenerative tears). There were 17 patients whose injuries could not be classified according to the Palmer classification: 13 had volar or dorsal capsular TFC detachment and 4 had a horizontal tear of the articular disk.

CONCLUSION

Using high-resolution 3-T MRI, we have not only found all the TFCC injuries described in the Palmer classification, additional injury types were found in this study, including horizontal tear of the TFC and capsular TFC detachment. We propose the modified Palmer classification and add the injury types that were not included in the original Palmer classification.

MRI of the Extensor Tendons of the Wrist

OBJECTIVE

This article reviews the normal anatomy of the extensor tendons of the wrist as well as the clinical presentation and MRI appearances of common tendon abnormalities, such as tears, tenosynovitis, intersection syndromes, and associated or predisposing osseous findings. Treatment options are also discussed.

CONCLUSION

We review the anatomy and normal MRI appearance of the clinically important dorsal extensor tendons of the wrist, in addition to the spectrum of abnormalities associated with these tendons.

High-resolution 3T Magnetic Resonance Imaging of the Triangular Fibrocartilage Complex in Chinese Wrists: Correlation with Cross-sectional Anatomy

BACKGROUND

The injury of the triangular fibrocartilage complex (TFCC) is a common cause of ulnar-sided wrist pain. The aim of this study was to investigate if the high-resolution 3T magnetic resonance imaging (MRI) could demonstrate the detailed complex anatomy of TFCC in Chinese.

METHODS

Fourteen Chinese cadaveric wrists (from four men and three women; age range at death from 30 to 60 years; mean age at 46 years) and forty healthy Chinese wrists (from 20 healthy volunteers, male/female: 10/10; age range from 21 to 53 years with a mean age of 32 years) in Beijing Jishuitan Hospital from March 2014 to March 2016 were included in this study. All cadavers and volunteers had magnetic resonance (MR) examination of the wrist with coronal T1-weighted and proton density-weighted imaging with fat suppression in three planes, respectively. MR arthrography (MRAr) was performed on one of the cadaveric wrists. Subsequently, all 14 cadaveric wrists were sliced into 2 mm thick slab with band saw (six in coronal plane, four in sagittal plane, and four in axial plane). The MRI features of normal TFCC were analyzed in these specimens and forty healthy wrists.

RESULTS

Triangular fibrocartilage, the ulnar collateral ligament, and the meniscal homolog could be best observed on images in coronal plane. The palmar and dorsal radioulnar ligaments were best evaluated in transverse plane. The ulnotriquetral and ulnolunate ligaments were best visualized in sagittal plane. The latter two structures and the volar and dorsal capsules were better demonstrated on MRAr.

CONCLUSION

High-resolution 3T MRI is capable to show the detailed complex anatomy of the TFCC and can provide valuable information for the clinical diagnosis in Chinese.

Ulnar-sided wrist pain in the athlete (TFCC/DRUJ/ECU)

PURPOSE OF REVIEW

The goal of this manuscript is to review key historic and recent literature regarding extensor carpi ulnaris (ECU), triangular fibrocartilage complex (TFCC) and distal radioulnar joint (DRUJ) injuries, particularly in athletes.

RECENT FINDINGS

Many recent studies examining the ECU focus on clinical and radiographic diagnosis. Several physical exam findings are described in addition to the use of MRI and US. Imaging studies must be clinically correlated due to high incidence of findings in asymptomatic patients. In regard to the TFCC/DRUJ, there are numerous recent studies that support the use of MRA as an adjunctive diagnostic study. There are also a number of repair constructs that are described for the various different kinds of TFCC pathology reviewed here. In summary, there are a number of options for the diagnosis and treatment of ulnar-sided wrist pain. Patient factors, especially in the athletic population, must be taken into account when approaching any patient with these pathologies.

Axial traction magnetic resonance imaging (MRI) of the glenohumeral joint in healthy volunteers: initial experience

OBJECTIVE

Evaluate technical feasibility and potential applications of glenohumeral (GH) joint axial traction magnetic resonance imaging (MRI) in healthy volunteers.

MATERIALS AND METHODS

Eleven shoulders were imaged in neutral and with 4kg axial traction at 3T. Quantitative measurements were assessed.

RESULTS

Axial traction was well tolerated. There was statistically significant widening of the superior GH joint space (p=0.002) and acromial angle (p=0.017) with traction. Inter-rater agreement was high.

CONCLUSION

GH joint axial traction MRI is technically feasible and well tolerated in volunteers. Traction of the capsule, widening of the superior GH joint space and acromial angle were observed.

Subluxation of the peroneus long tendon in the cuboid tunnel: is it normal or pathologic? An ultrasound and magnetic resonance imaging study

OBJECTIVE

To evaluate the position of the peroneus longus (PL) tendon relative to the cuboid tuberosity and cuboid tunnel during ankle dorsiflexion and plantarflexion using ultrasound and MRI.

MATERIALS AND METHODS

The study population included two groups: 20 feet of 10 asymptomatic volunteers who underwent prospective dynamic ultrasound and 55 ankles found through retrospective review of routine ankle MRI examinations. The location of the PL tendon at the cuboid tuberosity and cuboid tunnel was designated as completely within the tunnel, indeterminate, or subluxed with respect to ankle dorsiflexion and plantarflexion.

RESULTS

On dynamic ultrasound, the PL tendon was perched plantar to the cuboid tuberosity in dorsiflexion, and glided to enter the cuboid tunnel distal to the tuberosity in plantarflexion in all 20 feet. On the MRI evaluation, there was a statistically significant difference (p = 0.0006) in the location of the PL tendon between the ankles scanned in dorsiflexion and plantarflexion.

CONCLUSION

Based on our findings on ultrasound and MRI, the PL tendon can glide in and out of the cuboid tunnel along the cuboid tuberosity depending on ankle position. Thus, "subluxation" of the tendon as it curves to enter the cuboid tunnel, which to the best of our knowledge has not yet been described, should be recognized as a normal, position-dependent phenomenon and not be reported as pathology.

Association between distal ulnar morphology and extensor carpi ulnaris tendon pathology

OBJECTIVE

The purpose of this study was to evaluate the association between distal ulnar morphology and extensor carpi ulnaris (ECU) tendon pathology.

MATERIALS AND METHODS

We retrospectively reviewed 71 adult wrist MRI studies with ECU tendon pathology (tenosynovitis, tendinopathy, or tear), and/or ECU subluxation. Subjects did not have a history of trauma, surgery, infection, or inflammatory arthritis. MRI studies from 46 subjects without ECU tendon pathology or subluxation were used as controls. The following morphological parameters of the distal ulna were measured independently by two readers: ulnar variance relative to radius, ulnar styloid process length, ECU groove depth and length. Subjects and controls were compared using Student's t test. Inter-observer agreement (ICC) was calculated.

RESULTS

There was a significant correlation between negative ulnar variance and ECU tendon pathology (reader 1 [R1], P = 0.01; reader 2 [R2], P < 0.0001; R1 and R2 averaged data, P < 0.0001) and ECU tendon subluxation (P = 0.001; P = 0.0001; P < 0.0001). In subjects with ECU tendon subluxation there was also a trend toward a shorter length (P = 0.3; P <0.0001; P = 0.001) and a shallower ECU groove (P = 0.01; P = 0.03; P = 0.01; R1 and R2 averaged data with Bonferroni correction, P = 0.08). ECU groove depth (P = 0.6; P = 0.8; P = 0.9) and groove length (P = 0.1; P = 0.4; P = 0.7) showed no significant correlation with ECU tendon pathology, and length of the ulnar styloid process showed no significant correlation with ECU tendon pathology (P = 0.2; P = 0.3; P = 0.2) or subluxation (P = 0.4; P = 0.5; P = 0.5). Inter-observer agreement (ICC) was >0.64 for all parameters.

CONCLUSION

Distal ulnar morphology may be associated with ECU tendon abnormalities.

Sports-related extensor carpi ulnaris pathology: a review of functional anatomy, sports injury and management

The extensor carpi ulnaris (ECU) muscle plays a key role not only in the active movements of wrist extension and ulnar deviation but also in providing stability to the ulnar side of the wrist. Its position relative to the other structures in the wrist changes with forearm pronation and supination. As such, it must be mobile yet stable. The ECU tendon relies on specific stabilising structures to hold it in the correct positions to perform its different functions. These structures can be injured in a variety of different athletic activities such as tennis, golf and rugby league, yet their injury and disruption is predictable when the mechanics of the ECU and the techniques of the sport are understood. The ECU tendon is also vulnerable to tendon pathologies other than instability. It lies subcutaneously and is easily palpated and visualised with diagnostic ultrasound, allowing early diagnosis and management of its specific conditions. Treatment includes rest, splintage and surgery with each modality having specific indications and recognised outcomes. This review described the functional anatomy in relevant sporting situations and explained how problems occur as well as when and how to intervene.

Pathologies of the extensor carpi ulnaris (ECU) tendon and its investments in the athlete

Those who have dedicated significant time to the study and care of stick-and-ball athletes have an appreciation for the unique anatomy, unusual forces, and proclivity for injury. It is imperative that hand surgeons involved in the care of baseball, hockey, tennis, and golf athletes appreciate the anatomic and mechanical elements of extensor carpi ulnaris (ECU) pathology. It is necessary to maintain a high level of suspicion for ECU problems, among other ulnar wrist pathologies, as well as acute diagnostic skill and a portfolio of therapeutic alternatives for their treatment.