Subluxation of the distal radioulnar joint as a predictor of foveal triangular fibrocartilage complex tears

Distal Radioulnar Joint Instability

SUMMARY

The distal radioulnar joint (DRUJ) is vital to the stability and function of the wrist and forearm. The osseous morphology is variable and provides little stability. A complex of confluent soft tissues is the primary stabilizer; however, the contribution of each component has yet to be elucidated. It has become increasingly clear that the anatomic fixation of distal radius fractures restores DRUJ stability, obviating the need for additional DRUJ stabilization. This review will describe the anatomy and biomechanics of the DRUJ and discuss injury patterns, treatments, and clinical results.

Magnetic Resonance Imaging Assessment of Ulnar Wrist Pain: A Practical Guide for Surgeons

Ulnar-sided wrist pain is a challenging clinical scenario due to multiple overlapping pathologies and involved anatomic structures. Advanced imaging such as magnetic resonance imaging can be used as an effective diagnostic adjunct if interpreted correctly. In this article, clinically relevant structures and radiographic correlates of the ulnar wrist are discussed and a corresponding systematic approach to reviewing magnetic resonance imaging is presented.

Comparing the Outcomes of Suture Anchor Repair and Rein-Type Capsular Suture for Triangular Fibrocartilage Complex Foveal Tears With a Minimum 2-Year Follow-Up

PURPOSE

Recent biomechanical studies have highlighted the importance of foveal reinsertion when repairing triangular fibrocartilage complex (TFCC) injury with foveal tears. However, clinical studies comparing different repair techniques are scarce. We compared the clinical outcomes of suture anchor repair and rein-type capsular suture in patients with TFCC palmer 1B foveal tears with a minimum of 2-year follow-up.

METHODS

This was a single-surgeon, single-center, retrospective, comparative study. We included patients who underwent TFCC repair surgery due to a foveal tear from December 2013 to October 2018 with a minimum follow-up of 24 months. Postoperative Quick Disabilities of Arm, Shoulder, and Hand (QuickDASH) score, Modified Mayo Wrist Score, visual analogue scale for pain, wrist range of motion, and grip strength were compared. We also measured the maximal ulnar head displacement with dynamic ultrasound to quantify distal radioulnar joint stability.

RESULTS

In total, 103 patients were in the suture anchor group (group A) and 84 patients in the rein-type capsular suture group (group B). The mean follow-up time exceeded three years for both groups. There was a minimal difference regarding QuickDASH score, visual analogue scale for pain, and grip strength ratio between the two groups. The rein-type group had significantly better Modified Mayo Wrist Score. The suture anchor group showed better distal radioulnar joint stability with dynamic ultrasound, but was more limited in ulnar deviation. However, these differences are most likely clinically insignificant.

CONCLUSIONS

Both suture anchor repair and rein-type capsular suture yielded satisfactory results for TFCC 1B foveal tear in a minimum of 2-year follow-up. The functional scores were similar, and no major complications or recurrent instability were noted in either group.

TYPE OF STUDY/LEVEL OF EVIDENCE

Retrospective Therapeutic Comparative Investigation IV.

Foveal triangular fibrocartilage complex pathology: a potentially under-recognized injury

The primary aim of the present study was to present a case series of 24 patients with foveal triangular fibrocartilage complex (TFCC) injuries that were treated with arthroscopically assisted TFCC foveal repair. In total, 19 patients had a stable distal radioulnar joint (DRUJ) and five had an unstable DRUJ. Despite this, all patients were found to have a foveal tear upon DRUJ arthroscopy. Magnetic resonance imaging (MRI) scans detected only eight out of 23 patients with foveal injuries. In addition to their foveal injury, 19 of the 24 patients had additional pathology that required treatment. At a mean follow-up of 18 months, there was a statistically significant improvement in pain, range of motion, grip strength and functional scores. In this study, we demonstrate that having a stable DRUJ upon clinical examination and normal MRI findings does not rule out foveal TFCC injury and a high index of clinical suspicion is needed when managing patients with ulnar sided wrist pain.Level of evidence: IV.

Dynamic Computed Tomography of the Distal Radioulnar Joint Versus Magnetic Resonance Imaging in Detecting Foveal Tears of the Triangular Fibrocartilage Complex

BACKGROUND

Diagnosis of foveal triangular fibrocartilage complex (TFCC) tears remains difficult. The purpose of this study was to evaluate whether dynamic computed tomography (CT) of the distal radioulnar joint (DRUJ) has a higher sensitivity in detecting foveal tears of the TFCC when compared with magnetic resonance imaging (MRI).

METHODS

A database query identified all patients above the age of 18 years with suspected foveal TFCC injuries who underwent bilateral dynamic CT imaging of the DRUJ, static 3T MRI, and subsequent wrist arthroscopy. All patients had evidence of foveal tenderness on clinical examination. The imaging results were validated with wrist arthroscopy.

RESULTS

Twelve patients with a mean age of 31 years (range, 18-53 years) were identified. Eight patients were diagnosed with a complete foveal detachment of the TFCC on wrist arthroscopy. Of the 8 patients with a foveal tear on DRUJ arthroscopy, only 3 had a preoperative physical examination suggestive of DRUJ instability. Magnetic resonance imaging identified foveal injuries in 4 of these 8 patients (sensitivity, 50%), and 3 of these were identified as only partial tears. Dynamic CT identified instability of DRUJ in 6 of 8 patients (sensitivity, 75%). Seven of 8 patients had imaging findings suggestive of a foveal tear when including either MRI or CT imaging (sensitivity, 88%). Of the 4 patients with an intact foveal attachment on arthroscopy, 3 (specificity, 75%) had a stable DRUJ on CT and all 4 (specificity, 100%) had an intact foveal attachment on MRI.

CONCLUSION

Sixty-two percent of patients with foveal tears on arthroscopy have a stable DRUJ on clinical examination. When combining MRI and dynamic CT imaging of the DRUJ, the sensitivity of detecting a foveal TFCC tear approaches 88% compared with a gold standard of wrist arthroscopy.

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.

Ulnar positive variance associated with TFCC foveal tear

OBJECTIVE

The ulnar positive variance (UPV) can be observed on simple radiography due to a triangular fibrocartilage complex (TFCC) foveal tear. This study investigated to identify how much radiographic UPV occurs due to a TFCC foveal tear, which may be misdiagnosed as an ulnar impaction syndrome (UIS).

MATERIALS AND METHODS

One hundred forty patients who underwent arthroscopic transosseus TFCC foveal repair from March 2013 to March 2019 in our institution were enrolled in this study. Ulnar variances were measured in preoperative, postoperative 6 weeks, 1-year follow-up wrist posteroanterior (PA) radiograph, and power grip PA radiograph of the affected wrist and were compared with those of the same patient's unaffected wrist.

RESULTS

In the neutral wrist PA radiograph, ulnar variance increased by 0.56 mm (p < 0.001) after TFCC foveal tear compared to the unaffected side. In the power grip view, ulnar variance also increased by 0.39 mm (p < 0.001) in the affected wrist. The preoperative ulnar positive variance was reduced after an arthroscopic transosseous TFCC foveal repair from 0.56 to 0 mm (p < 0.001). No significant statistical difference was observed between an Atzei class 2 and 3 TFCC tear (0.56 mm vs. 0.41 mm, p = 0.263).

CONCLUSION

This study revealed that TFCC foveal tear induces 0.56 mm of radiologic UPV, which was successfully corrected after arthroscopic transosseous TFCC foveal repair. Therefore, UPV associated with TFCC foveal tear should not be misdiagnosed as an UIS. Also, when ulnar shortening osteotomy is planned in case of UIS combined with TFCC foveal tear, the amount of UPV induced by TFCC foveal tear should be considered to prevent over-shortening.

Midterm Results of Arthroscopy-Assisted "Tent Form" Triangular Fibrocartilage Complex Repair With Dorsal Distal Radioulnar Joint Capsule Imbrication for Posttraumatic Chronic Distal Radioulnar Joint Instability

PURPOSE

To evaluate the outcomes of "tent form" triangular fibrocartilage complex (TFCC) repair combined with dorsal distal radioulnar joint (DRUJ) capsule imbrication for posttraumatic chronic DRUJ instability.

METHODS

All patients treated with arthroscopic "tent form" TFCC repair and DRUJ capsule imbrication from 2016 to 2019 were retrospectively reviewed. The inclusion criteria were symptomatic chronic DRUJ instability for >6 months and dorsal DRUJ subluxation on magnetic resonance imaging. The Disabilities of the Arm, Shoulder, and Hand score, Patient-Rated Wrist Evaluation, grip strength, Modified Mayo Wrist Score, range of motion, and distal radioulnar joint stability were assessed for a minimum of 2 years postoperatively.

RESULTS

Thirty-eight patients were included in the final analysis. The average follow-up duration was 35.6 months (range, 24-48 months). The 24-month postoperative grip strengths and 3-dimensional motions of wrist were not significantly different from that of the nonoperated wrist. Compared with their preoperative status, Disabilities of the Arm, Shoulder, and Hand score, Patient-Rated Wrist Evaluation, and Modified Mayo Wrist Score indicated the significant improvement with P values of .001, .001, and .002, respectively.

CONCLUSIONS

In chronic DRUJ instability with a loosening dorsal capsule, "tent form" TFCC transcapsular repair combined with DRUJ capsule imbrication restored the integrity of TFCC and dorsal DRUJ capsule and achieved a promising outcome. We recommend this procedure as an option of treatment for patients with posttraumatic chronic DRUJ instability.

LEVEL OF EVIDENCE

IV, case series.

MRI Findings in Patients Undergoing Triangular Fibrocartilage Complex Repairs Versus Patients Without Ulnar-Sided Wrist Pain

Background: The clinical picture of ulnar-sided wrist pain is oftentimes confusing because various pathologies may be coexistent. In this study, we aimed: (1) to compare the prevalence of potential causes of ulnar-sided wrist pain on magnetic resonance imaging (MRI) in patients who underwent triangular fibrocartilage complex (TFCC) repair and control subjects: and (2) to evaluate whether inferior clinical results were associated with specific patient characteristics or other potential causes of ulnar-sided wrist pain. Methods: We included 67 patients who underwent a TFCC repair and 67 control subjects. The MRI scans were examined for sources of ulnar-sided wrist pain. After TFCC repair, 42 patients (63%) completed surveys, including Quick Disabilities of the Arm, Shoulder and Hand and pain scores. Bivariate analysis was performed to compare our groups and to identify factors associated with our outcomes. Results: We found significantly higher rates of distal radioulnar joint (DRUJ) arthritis (P = .033), extensor carpi ulnaris (ECU) pathology (P = .028), and ulnar styloid fractures (P = .028) in patients with TFCC repairs. With increasing age, increasing pathology in the pisotriquetral joint (P = .040), more ulnocarpal abutment (P = .0081), and more degenerative tears (P < .001) were seen in both groups. No demographic characteristics or MRI findings were significantly associated with our outcomes. Conclusions: We observed higher rates of DRUJ arthritis and ECU pathology in patients with TFCC tears undergoing repair compared with age- and sex-matched controls. This may be due to damage to the TFCC itself altering relationships of the DRUJ and the ECU subsheath, or it may reflect various pathologies that cause ulnar-sided wrist pain and drive patients toward surgery.

Postoperative immobilization using a short-arm cast in the semisupination position is appropriate after arthroscopic triangular fibrocartilage complex foveal repair

AIMS

The aim of this study was to assess and compare active rotation of the forearm in normal subjects after the application of a short-arm cast (SAC) in the semisupination position and a long-arm cast (LAC) in the neutral position. A clinical study was also conducted to compare the functional outcomes of using a SAC in the semisupination position with those of using a LAC in the neutral position in patients who underwent arthroscopic triangular fibrocartilage complex (TFCC) foveal repair.

METHODS

A total of 40 healthy right-handed volunteers were recruited. Active pronation and supination of the forearm were measured in each subject using a goniometer. In the retrospective clinical study, 40 patients who underwent arthroscopic foveal repair were included. The wrist was immobilized postoperatively using a SAC in the semisupination position (approximately 45°) in 16 patients and a LAC in 24. Clinical outcomes were assessed using grip strength and patient-reported outcomes. The degree of disability caused by cast immobilization was also evaluated when the cast was removed.

RESULTS

Supination was significantly more restricted with LACs than with SACs in the semisupination position in male and female patients (p < 0.001 for both). However, pronation was significantly more restricted with SACs in the semisupination position than with LACs in female patients (p = 0.003) and was not significantly different in male patients (p = 0.090). In the clinical study, both groups showed improvement in all parameters with significant differences in grip strength, visual analogue scale scores for pain, modified Mayo Wrist Score, the Disability of the Arm, Shoulder, and Hand (DASH) score, and the Patient-Rated Wrist Evaluation (PRWE) score. No significant postoperative differences were noted between LACs and SACs in the semisupination position. However, the disability caused by immobilization in a cast was significantly higher in patients who had a LAC on the dominant hand (p < 0.001).

CONCLUSION

We found that a SAC in the semisupination position is as effective as a LAC in restricting pronation of the forearm. In addition, postoperative immobilization with a SAC in the semisupination position resulted in comparable pain scores and functional outcomes to immobilization with a LAC after TFCC foveal repair, with less restriction of daily activities. Therefore, we recommend that surgeons consider using a SAC in the semisupination position for postoperative immobilization following TFCC foveal repair for dorsal instability of the distal radioulnar joint. Cite this article: Bone Joint J 2022;104-B(2):249-256.

Distal Radioulnar Joint Instability

Instability of the distal radioulnar joint is a source of ulnar-sided wrist pain and functional impairment. Symptomatic instability may present acutely, after a recent traumatic injury, or in a delayed fashion as chronic instability following a history of a traumatic event. A detailed understanding of the complex anatomy, biomechanics, and stabilizing structures of the distal radioulnar joint is important to evaluate and treat acute and chronic instability. This article describes the pathophysiology of distal radioulnar joint instability with attention to the anatomic structures involved and provides information about evaluation and treatment.

Experience with Diagnosis and Management of Distal Radioulnar Joint Instability

Objective  The aim of this study is to review our cumulative experience with diagnosis and treatment of distal radioulnar joint (DRUJ) instability and to present our treatment algorithm. Materials and Methods  Retrospective review identified 112 patients who had 126 episodes of care for DRUJ instability at a single institution over a 21-year period. Those diagnosed acutely or subacutely were treated with immobilization of the wrist and elbow for 6 weeks, while those with chronic instability had anatomic reconstruction of the dorsal and palmar radioulnar ligaments with tendon autograft or an alternative arthroscopic treatment with our thermal annealing technique. Short-term treatment failures and surgical complications were recorded. Nonparametric statistical tests were used to analyze key long-term outcome measures including ulnar wrist pain and DRUJ stability indicated by the dorsopalmar stress test. Results  At mean 7-year follow-up, eight patients in the acute-injury cohort had statistically significant improvements in wrist pain and DRUJ instability ( p  < 0.001). In both the 22-patient anatomic reconstruction cohort and the 37-patient arthroscopically treated group, there were also statistically significant improvements in wrist pain and DRUJ stability ( p  < 0.001) at mean 9-year follow-up. The majority of patients in all three groups was satisfied with treatment outcome, though some required secondary procedures. Conclusion  Early clinical diagnosis of DRUJ instability using the dorsopalmar stress test provides an opportunity for effective nonsurgical treatment. For chronic presentation, we recommend our arthroscopic thermal annealing technique for mild or moderate instability and open anatomic reconstruction of the radioulnar ligaments for severe instability. Level of Evidence  This is a Level IV, therapeutic study.

Influence of TFCC foveal tear on the location of lunate chondromalacia in ulnar impaction syndrome

OBJECTIVE

The purpose of this study was to identify the location of lunate chondromalacia and to compare the difference in location according to presence or absence of triangular fibrocartilage complex (TFCC) foveal tear, which induces distal radioulnar joint (DRUJ) instability.

METHODS

We performed a retrospective study of 97 patients (102 wrists) who were diagnosed with and treated for idiopathic ulnar impaction syndrome (UIS) between 2014 and 2018. Subjects were divided into two groups according to presence or absence of TFCC foveal tear with DRUJ instability. Group I had UIS without a TFCC foveal tear (52 wrists, mean age of 43.2 years), while Group II had UIS with a TFCC foveal tear (50 wrists, mean age of 45.3 years). There was no significant difference in age, sex, or duration of symptoms between the two groups. All patients underwent wrist MR Arthrography (MRA) in the same gantry, and all scanned coronal sections of the lunate were standardized into 10 slices, including the whole anteroposterior width of the lunate. Each slice was sequentially numbered from dorsal to volar side, and the location of chondromalacia was marked in each numbered section. Radiological parameters including ulnar variance and ulnolunate distance (ULD), which indicated the distance between the ulnar head and lunate, were measured in the wrist series.

RESULTS

The most frequent location of lunate chondromalacia was slightly to the volar side of the lunate in both groups. Group I showed a higher frequency of chondromalacia in the volar side of the lunate. In Group II, chondromalacia was identified with high frequency not only on the volar side of the lunate but also on the dorsal side. In other words, Group II showed broader chondromalacia in the lunate. There was no significant difference in ulnar variance (Group I, 3.19 ± 1.42 mm; Group II, 2.76 mm ± 1.67 mm) or ulnolunate distance (Group I, 1.66 ± 0.94 mm; Group II, 2.05 mm ± 0.87 mm). The average ULD decreased during radial deviation but increased during ulnar deviation.

CONCLUSION

This study showed that lunate chondromalacia associated with idiopathic ulnar impaction syndrome occurs more frequently on the volar side of the lunate. Also, TFCC foveal tear, which causes DRUJ instability, leads to broader lunate chondromalacia in idiopathic ulnar impaction syndrome. Therefore, further analysis of the pattern of lunate chondromalacia can provide a clue for DRUJ instability.

Subluxation of the extensor carpi ulnaris on magnetic resonance imaging on neutral wrist position: correlation with tenosynovitis of the extensor carpi ulnaris and translation of the distal radioulnar joint

OBJECTIVE

To identify the subluxation degrees of extensor carpi ulnaris (ECU) tendon on neutral wrist MRI in patients with ulnar-sided wrist pain and to evaluate the relationships of ECU subluxation with accompanying imaging findings such as ECU tenosynovitis, distal radioulnar joint (DRUJ) stability, and triangular fibrocartilage complex (TFCC) pathology.

MATERIALS AND METHODS

A total of 297 MRIs of 292 patients having ulnar side pain were reviewed retrospectively. Degrees of ECU subluxation was classified into four grades: grade 0, no subluxation; grade 1, tendon displacement < 50% of the tendon width; grade 2, tendon displacement 51 to 99% of the tendon width; and grade 3, tendon displacement of 100% of the tendon width. ECU tenosynovitis, ECU tendinosis, injuries of triangular fibrocartilage and distal radioulnar ligaments (DRUL), translation ratio of the DRUJ, rotation angle of the DRUJ, and the width, depth, and length of the ulnar groove were assessed on wrist MRI. The relationships between degree of ECU subluxation and these imaging findings were investigated.

RESULTS

Women had higher subluxation degrees of the ECU tendon (p = 0.001). Tenosynovitis of the ECU, sprain of the dorsal DRUL, dorsovolar translation ratio and rotation angle of the DRUJ, and depth and length of the ulnar groove were statistically significantly related to the subluxation degree of the ECU tendon (p = 0.000).

CONCLUSION

High-grade subluxation of the ECU tendon was strongly correlated with ECU tenosynovitis and DRUJ translation. Clinicians and radiologists should scrutinize imaging findings, particularly when patients with ulnar-sided wrist pain have high-grade subluxation of the ECU tendon.

[The ulnocarpal complex : New clinical and radiological considerations]

CLINICAL ISSUE

The triangular fibrocartilage complex (TFCC) is an anatomically complex structure with high demands on spatial and contrast resolution in imaging.

RADIOLOGICAL METHODS

The central, predominantly avascular articular disc can be distinguished from the ligamentous, vascularized periphery. Imaging methods include magnetic resonance imaging (MRI, preferably contrast-enhanced) as well as MR and computed tomography (CT) arthrography.

DIAGNOSTIC INNOVATIONS

While high-resolution MRI represents the standard diagnostic tool for the TFCC in general, arthrographic imaging is particularly useful for assessment of the foveal (proximal) lamina of the TFCC. In radiological reporting, the convergence of the TFCC periphery towards the ulnar styloid process and the ulnar fovea must be considered.

ACHIEVEMENTS

The Palmer classification is suitable for evaluating lesions of the articular disc, whereas the Atzei classification is superior for lesions of the ulnar TFCC insertions.

PRACTICAL RECOMMENDATION

Use of a high-resolution examination technique and anatomy-based image interpretation are important for reliable MRI of the TFCC.

Surgical Repair of Triangular Fibrocartilage Complex Tears: A Systematic Review

Objective  This study systematically reviews the outcomes of surgical repair of triangular fibrocartilage complex (TFCC) tears. Existing surgical techniques include capsular sutures, suture anchors, and transosseous sutures. However, there is still no consensus as to which is the most reliable method for ulnar-sided peripheral and foveal TFCC tears. Methods  A systematic review of MEDLINE and EMBASE was performed according to PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. The focus was on traumatic Palmer 1B ulna-sided tears. Twenty-seven studies were included, including three comparative cohort studies. Results  There was improvement in all functional outcome measures after repair of TFCC tears. The outcomes following peripheral and foveal repairs were good overall: Mayo Modified Wrist Evaluation (MMWE) score of 80.1 and 85.1, Disabilities of the Arm, Shoulder and Hand (DASH) score of 15.7 and 15.8, grip strength of 80.3 and 92.7% (of the nonoperated hand), and pain intensity score of 2.1 and 1.7, respectively. For peripheral tears, transosseous suture technique achieved better outcomes compared with capsular sutures in terms of grip strength, pain, Patient-Rated Wrist Evaluation (PRWE), and DASH scores (grip 85.8 vs. 77.7%; pain 1.5 vs. 2.2; PRWE 11.6 vs. 15.8; DASH 14.4 vs. 16.1). For foveal tears, transosseous sutures achieved overall better functional outcomes compared with suture anchors (MMWE 85.4 vs. 84.9, DASH 10.9 vs. 20.6, pain score 1.3 vs. 2.1), but did report slightly lower grip strength than the group with suture anchors (90.2 vs. 96.2%). Arthroscopic techniques achieved overall better outcomes compared with open repair technique. Conclusion  Current evidence demonstrates that TFCC repair achieves good clinical outcomes, with low complication rates. Level of Evidence  This is a Level IV, therapeutic study.

Imaging of the Hand and Wrist

Imaging plays a key role in the evaluation and treatment planning of hand and wrist injuries in athletes. Depending on the suspected injury, a combination of conventional radiographs, computed tomography, magnetic resonance imaging, magnetic resonance arthrography, and/or ultrasound may be indicated. This article reviews the strengths and limitations of these imaging modalities and how they can be utilized in commonly encountered clinical questions.

Changes in the morphology of the triangular fibrocartilage complex (TFCC) on magnetic resonance arthrography related to disruption of ulnar foveal attachment

OBJECTIVE

To assess whether a proximal ligamentous component (PLC) of the triangular fibrocartilage complex (TFCC) with a distally prolapsing morphology is associated with the presence of a TFCC foveal tear on arthroscopy.

METHODS

One-hundred thirty-two patients (134 wrists) who underwent MR arthrography and subsequent wrist arthroscopy between September 2014 and March 2018 were retrospectively evaluated. The degree of distal PLC prolapse was measured on coronal MR arthrography using the height-to-length ratio (HLR). Subjects' demographics, ulnar variance, presence of a degenerative TFCC tear, and ulnar styloid nonunion were assessed. The association between specific variables and the presence of a foveal tear was investigated.

RESULTS

A TFCC foveal tear was identified in a total of 101 of 134 wrists examined by arthroscopy. Univariable analysis showed that the HLR of the PLC was significantly greater in the foveal tear group compared with the intact fovea group (44.6 vs. 38.9%, respectively, p < 0.001). Multivariable analysis showed that HLR was positively associated with a foveal tear (odds ratio [OR], 1.211; p < 0.001). The estimated cut-off value of the HLR was 41% (area under the curve [AUC] 0.77).

CONCLUSIONS

PLCs with a distal prolapse pattern and large HLR are associated with TFCC foveal tears. The HLR of the PLC measured on coronal MR images can therefore be used as an additional predictor of tears of the foveal attachment of the TFCC.

Evaluation of radiological instability signs in the distal radioulnar joint in children and adolescents with arthroscopically-verified TFCC tears

INTRODUCTION

Recent reports in the adult literature reported the use of standardized radiographic measurement techniques to determine distal radioulnar joint (DRUJ) instability. The aim of this study was to evaluate the efficacy and accuracy of (1) the MRI-based modified radioulnar ratio technique and (2) the pisoscaphoid (PiSca) and radioulnar (RaUl) distances in true lateral radiographs in children and adolescents with arthroscopically-verified TFCC tears.

MATERIALS AND METHODS

We retrospectively assessed lateral wrist radiographs and axial MRI sequences of 18 adolescent patients (22 wrists) who had arthroscopically-confirmed TFCC tears and compared them to similar imaging of a control group of 28 healthy patients (28 wrists). Three raters assessed the images twice in a 2-week interval. Intraclass correlation coefficients (ICCs), unifactorial ANOVA, and ROC analysis were performed with regards to the different radiographic variables.

RESULTS

The interrater ICCs were almost perfect for all measurements except RaUl1, which showed a substantial agreement (0.751) among the three observers. The intrarater ICCs were almost perfect when measuring PiSca and MRI, and substantial to almost perfect for RaUl. Pearson's correlation showed a moderate, positive correlation between PiSca and RaUl distances (r = 0.608; p < 0.001), and a moderate, negative correlation between RaUl distance and MRI shift (r = - 0.486; p = 0.010). When the three core groups (peripheral, central tear, controls) were compared to each other regarding the radiographic instability parameters, only the MRI shift revealed a statistically significant difference (p = 0.003). Comparisons revealed significant differences between patients and controls (p = 0.004) and peripheral tears vs. controls (p = 0.001 and p = 0.010). The ROC analysis revealed a significant AUC only for the MRI (AuC 0.787 and p = 0.002).

CONCLUSIONS

Children and adolescents with peripheral TFCC tears showed significantly increased instability parameters in MRI compared to controls. These measurement techniques are no replacement for a thorough clinical examination but may be helpful for indicating diagnostic wrist arthroscopy in ambiguous cases.

LEVEL OF EVIDENCE

Level III; Diagnostic.

[Radiology of the distal radioulnar joint and the ulnocarpal complex]

X-ray images exposed in neutral position and radiocarpally centred are essential in imaging of the distal radioulnar joint (DRUJ). The anatomic orientation of the DRUJ is favourable for acquiring transaxial scans to display its anatomy, subtle derangements, osteoarthritis and intra-articular fractures free from superpositions. The triangular fibrocartilage complex (TFCC) is the most important stabilizer of the DRUJ. Provided that a focused clinical indication is given, high-resolution images are acquired, and an intra-venous or intra-articular contrast-agent is applied, all TFCC structures and destabilizing lesions can be displayed with the use of CT and MRI.

Clinical Outcomes and Factors Influencing These Outcome Measures Resulting in Success After Arthroscopic Transosseous Triangular Fibrocartilage Complex Foveal Repair

PURPOSE

To analyze postoperative outcomes after arthroscopic transosseous triangular fibrocartilage complex (TFCC) foveal repair and identify factors affecting the clinical outcomes.

METHODS

This study retrospectively enrolled patients who were treated for TFCC foveal tears by arthroscopic transosseous TFCC foveal repair. The diagnosis of TFCC foveal tear was made based on medical history, physical examination, and magnetic resonance imaging, with confirmation via arthroscopic examination. Outcome evaluation was completed at a minimum of 2 years postoperatively, and patients were classified into 2 groups according to the minimal clinically important difference of the Patient-Rated Wrist Evaluation. Various factors including age, sex, trauma history, body mass index, symptom duration, hand dominance, ulnar variance, subluxation of the distal radioulnar joint, preoperative pain score, and functional status, as well as the cross-sectional area (CSA) of the pronator quadratus (PQ) muscle, were retrospectively analyzed using both univariate and multivariate analyses.

RESULTS

During the study period, 42 patients were treated for TFCC foveal tears. The functional status significantly improved after surgery. Overall, 27 and 15 patients showed good and poor functional outcomes, respectively, which were assessed according to the minimal clinically important difference of the Patient-Rated Wrist Evaluation. On univariate analysis, clinical outcomes were better in male patients (P = .035), younger patients (P = .022), and those with higher CSAs of the PQ muscles (P < .001). However, on multivariable logistic regression analysis, only a higher CSA of the PQ muscle was identified as an independent prognostic factor affecting clinical outcome after TFCC foveal repair (P = .004).

CONCLUSION

Arthroscopic transosseous TFCC complex foveal repair led to satisfactory results. However, lower PQ muscle CSA on magnetic resonance imaging was the most independent prognostic factor negatively affecting clinical outcomes.

LEVEL OF EVIDENCE

Level III, retrospective comparative study.

Treatment of distal radioulnar joint dislocation with spontaneous rupture of extensor tendon by Sauve-Kapandji osteotomy assisted by wrist arthroscopy: A case series and literature review

RATIONALE

Dislocation of the distal radioulnar joint and injury to distal forearm are commonly encountered. However, delayed diagnosis or misdiagnosis has been relatively rare due to improved diagnosis and treatment. Treatment of old dislocation of radioulnar joint is challenging due to development of secondary chronic instability and difficulties in restoration of joint function.

PATIENT CONCERNS

This report describes three cases of patients complained about inability to extend their little fingers.

DIAGNOSES

Local examination and X-ray revealed chronic ulnar joint dislocation.

INTERVENTION

Wrist arthroplasty was used to perform ulnar distal articular cleansing and repair of the triangular fibrocartilage complex (TFCC) articular cartilage. The Sauve-Kapandji osteotomy was performed to treat radial joint dislocation and stabilize ulnar joint. Repair of spontaneous fracture of the extensor tendon was also performed. Postoperative gypsum was used for immobilization for 4 weeks.

OUTCOMES

The follow-up results are reported. Based on Cooney wrist score, the preoperative scores were poor (55, 50, 60), while the post-operative scores were excellent (90, 85, 90) in all 3 cases.

LESSONS

Early and accurate diagnosis and treatment is important for the recovery of distal radius fracture for patients with dislocation of the ulnar joint. The correct treatment determines the degree of later functional recovery. Early surgical treatment is recommended for patients with unsatisfactory reset. Delayed diagnosis and treatment often lead to chronic and persistent lower ulnar joint subluxation or dislocation, or even osteoarthritis. All patients in this report showed great improvement in wrist function after surgery.

Where Is the Ulnar Styloid Process? Identification of the Absolute Location of the Ulnar Styloid Process Based on CT and Verification of Neutral Forearm Rotation on Lateral Radiographs of the Wrist

Background

The location of the ulnar styloid process can be confusing because the radius and the hand rotate around the ulna. The purpose of this study was to identify the absolute location of the ulnar styloid process, which is independent of forearm pronation or supination, to use it as a reference for neutral forearm rotation on lateral radiographs of the wrist.

Methods

Computed tomography (CT) images of 23 forearms taken with elbow flexion of 70° to 90° were analyzed. The axial CT images were reconstructed to be perpendicular to the distal ulnar shaft. The absolute location of the ulnar styloid process in this study was defined as the position of the ulnar styloid process on the axial plane of the ulnar head relative to the long axis of the humeral shaft with the elbow set in the position for standard lateral radiographs of the wrist. To identify in which direction the ulnar styloid is located on the axial plane of the ulnar head, the angle between “the line of humeral long axis projected on the axial plane of the ulna” and “the line passing the center of the ulnar head and the center of the ulnar styloid” was measured (ulnar styloid direction angle). To identify how volarly or dorsally the ulnar styloid should appear on the true lateral view of the wrist, the ratio of “the volar-dorsal diameter of the ulnar head” and “the distance between the volar-most aspect of the ulnar head and the center of the ulnar styloid” was calculated (ulnar styloid location ratio).

Results

The mean ulnar styloid direction angle was 12° dorsally. The mean ulnar styloid location ratio was 1:0.55.

Conclusions

The ulnar styloid is located at nearly the ulnar-most (the opposite side of the humerus with the elbow flexed) and slightly dorsal aspects of the ulnar head on the axial plane. It should appear almost midway (55% dorsally) from the ulnar head on the standard lateral view of the wrist in neutral forearm rotation. These location references could help clinicians determine whether the forearm is in neutral or rotated position on an axial CT/magnetic resonance imaging scan or a lateral radiograph of the wrist.

A Biomechanical Perspective on Distal Radioulnar Joint Instability

Background The purpose of this article was to review the anatomy, kinematics of the distal radioulnar joint (DRUJ), and to discuss definition, classification, and diagnosis of DRUJ instability. Methods A biomechanical perspective on physical examination of DRUJ ballottement test was documented. Physiological dynamic DRUJ translation and differences of the translation following sequential ligament sectioning and changes in different forearm and wrist positions were demonstrated. The clinical significance of each ligament's contribution to joint stability in specific wrist positions was addressed. Conclusion Each ligament stabilizing the DRUJ contributed to joint stability depending on the direction (palmer or dorsal) and different positions of the wrist and forearm. DRUJ ballottement test in each wrist and forearm position may detect tears of specific ligament stabilizing the DRUJ.

The "Four-Leaf Clover" Treatment Algorithm: A Practical Approach to Manage Disorders of the Distal Radioulnar Joint

Most symptomatic distal radioulnar joint (DRUJ) conditions result from derangements to several structures that may include the length, shape, and/or orientation of the articulating surfaces; the cartilage of the DRUJ and/or ulnocarpal joint; the DRUJ and/or ulnocarpal joint ligaments; and the extensor carpi ulnaris and/or pronator quadratus muscle. Once a complete diagnosis is made, often only one of these components is addressed, which results in suboptimal clinical outcomes. In this article, we present a treatment algorithm (the Four-Leaf Clover algorithm) to guide treatment of DRUJ pathology. The Four-Leaf Clover principle is a guiding algorithm, not a document forcing the surgeon to adopt one particular treatment. Its purpose is to provide treating physicians with a checklist that helps ensure that they do not miss any of the different components that need to be addressed for a complete treatment. Using the treatment algorithm, we should achieve satisfactory resolution of patients' symptoms after addressing the particular components in a stepwise approach.

Intra-articular Fractures of the Sigmoid Notch of the Distal Radius: Analysis of Progression to Distal Radial Ulnar Joint Arthritis and Impact on Upper Extremity Function in Surgically Treated Fractures

Background Studies have established an increased risk of radiocarpal joint posttraumatic arthritis in patients with displaced intra-articular fractures of the distal radius, although this phenomenon has yet to be evaluated in the distal radioulnar joint (DRUJ). Purpose We hypothesized that patients with displaced intra-articular fractures of the sigmoid notch would have a higher prevalence of DRUJ arthritis and greater upper extremity dysfunction after operative treatment of distal radius fractures compared with fractures without sigmoid notch involvement. We also hypothesized that the degree of sigmoid notch incongruity would be correlated with the grade of DRUJ arthritis and the severity of upper extremity dysfunction. Patients and Methods A retrospective review was conducted on surgically treated patients with distal radius fractures with pre- and/or postoperative computed tomography (CT) scans. Patients were divided into groups based on presence or absence of fracture extension into the sigmoid notch. Within the sigmoid notch group, postoperative CT scans were used to measure sigmoid notch fracture step-off and diastasis (mm), as well as volar or dorsal DRUJ subluxation (%). Patients were administered Disabilities of the Arm, Shoulder, and Hand (DASH) questionnaires and radiographs were obtained to grade DRUJ arthritis using the Kellgren-Lawrence (KL) radiographic criteria. Results Thirty-three patients were included (19 with sigmoid notch involvement and 14 without) with an average radiographic follow-up of 6.3 years (range: 3.5-10.1 years). DASH scores were available for all patients, and radiographic follow-up was available in 24 patients (73%). A trend toward higher grade of DRUJ arthritis and poorer average DASH was found in those with sigmoid notch involvement, but was not statistically different. In the sigmoid notch group there were poorer DASH scores in patients with coronal step-off > 1.0-mm (p < 0.05). There were no significant correlations between sigmoid notch step-off, diastasis or DRUJ subluxation and either KL grade of arthritis or DASH scores. Conclusion Fractures involving the sigmoid notch did not appear to have a greater prevalence of DRUJ posttraumatic arthritis in operatively treated patients at greater than 6 years of follow-up. Postoperative sigmoid notch step-off, diastasis or DRUJ subluxation had a minimal effect on upper extremity function, but fractures with a coronal step-off of > 1.0-mm exhibited higher levels of upper extremity dysfunction. Level of Evidence Prognostic, Level III-Case control.

Imaging of the Proximal and Distal Radioulnar Joints

The proximal and distal radioulnar joints form a unique articular arrangement between the radius and ulna, allowing pivot motion of the forearm and positioning the hand in space. Typically imaged in conjunction with the elbow, radiographs, computed tomography (CT), and MR imaging of the proximal radioulnar joint contribute unique diagnostic information. Because dysfunction of the distal radioulnar joint is often a result of instability, dynamic CT protocols stressing the joint in addition to anatomic imaging with radiographs and MR imaging is valuable. Detailed knowledge of the patient's clinical condition and careful selection of imaging protocols will maximize the benefits.

Detection of relaxin receptor in the dorsoradial ligament, synovium, and articular cartilage of the trapeziometacarpal joint

Basilar thumb osteoarthritis (OA) is postulated to occur due to ligament attenuation of the trapeziometacarpal (TM) joint. Relaxin is a peptide hormone, which loosens ligaments before childbirth, through remodeling of the extracellular matrix via upregulation of matrix metalloproteases (MMPs). We postulated that relaxin family peptide receptor 1 (RXFP-1), the receptor for circulating relaxin, was present in tissues of the TM joint. Ligaments and synovium were sampled from 15 patients during surgery for TM arthritis. We obtained trapezial cartilage from two autopsy donors and four patients. Tissues were fixed, paraffin embedded, and sectioned at 5 µm, then were immunostained for RXFP-1, as well as MMP-1, and MMP-13, using rabbit anti-human polyclonal antibodies. Eight DRL samples showed positive immunostaining for relaxin receptor, with 14/15 positively stained in synovium. Greater staining was seen in specimens obtained from women with more severe TM arthritis. Trapezial cartilage demonstrated receptor staining within chondrocytes in the middle and deep zones. Immunostaining for MMPs co-localized with relaxin receptor staining. Relaxin receptors are present at the ligament, cartilage, and synovium of the TM joint, indicating that it is a potential target for relaxin. This suggests that circulating relaxin may impact joint stability. The role of relaxin in cartilage and synovium may be related to its role in collagen regulation as a possible tissue response to OA.

Clinical and ultrasonographic evidence of a proximal positional fault of the radius. A case report

Positional faults are considered a possible underlying mechanism mimicking the symptoms of a joint sprain. Despite numerous clinical studies indicating the presence of positional faults, there is limited evidence of imaging studies confirming positional faults. This case report is a preliminary study that offers clinical and ultrasonographic evidence of a proximal positional fault of the radius, treated successfully with manual therapy techniques. Three weeks after a bike fall on the outstretched hand, the patient in this study presented with right wrist pain and a lack of progress with conventional conservative treatment (NSAIDs, rest and immobilization). Clinical findings indicating a proximal positional fault of the radius included pain during active pronation increased by associating a passive movement of the radius in a proximal direction and it was reduced by associating a passive movement of the radius in a distal direction. Ultrasonographic (US) images showed a reduction of radio-capitellar distance on the right side (11.4 mm) compared to the left side (13.3 mm). A positive response with a distal mobilization of the radius supported the proximal positional fault of the radius. After two manual therapy sessions, the patient had recovered normal asymptomatic function. The outcomes used to assess function and pain were active pronation range of motion, the Spanish version of the DASH questionnaire and a 0-10 numeric pain rating scale. Each measure was conducted prior and after each treatment session and one week post treatment. The patient was re-examined at 6 months follow-up, during which US images, demonstrated a normalization of the right radio-capitellar distance.

Arthroscopically assisted reconstruction of triangular fibrocartilage complex foveal avulsion in the ulnar variance-positive patient

PURPOSE

Our aim was to evaluate the clinical results of patients treated by arthroscopically assisted reconstruction of foveal avulsion injury of the triangular fibrocartilage complex (TFCC) using a suture anchor.

METHODS

We retrospectively reviewed the results of 15 patients (11 men and 4 women; mean age, 30.5 years) who underwent surgical procedures for the treatment of TFCC foveal avulsion at our hospital. The patients were followed up for a mean of 29 months. The patients had TFCC foveal avulsion caused by sprains (n = 8), falls (n = 4), playing baseball (n = 2), and a motor vehicle accident (n = 1). All the patients underwent magnetic resonance imaging. Radiographs obtained to assess ulnar variance (UV), ulnar-dorsal subluxation, and function of the wrist based on grip power; Disabilities of the Arm, Shoulder and Hand score; and Mayo wrist score were examined for all patients both preoperatively and postoperatively.

RESULTS

On preoperative magnetic resonance imaging, TFCC foveal avulsion was observed in 13 of 15 cases. The mean UV value based on preoperative simple radiographic findings was 1.7 ± 1.0 mm, and dorsal subluxation at the distal ulna improved from 2.9 ± 3.0 mm to 0.2 ± 0.9 mm (P = .017). In all cases the distal radioulnar joint instability disappeared postoperatively. Grip power (compared with the uninvolved limb) was 79.3% preoperatively and 82.9% postoperatively (P = .086). The Disabilities of the Arm, Shoulder and Hand scores were 28.4 points preoperatively and 16.6 points postoperatively (P = .061). The Mayo wrist scores were excellent in 10 cases, good in 2, and fair in 3, and the mean score improved significantly from 64 points preoperatively to 84 points postoperatively (P = .007).

CONCLUSIONS

Arthroscopic-assisted suture anchor reattachment of the TFCC in patients with traumatic TFCC foveal avulsion can prevent or reduce distal radioulnar joint instability and reduce pain even in chronic cases with positive UV.

LEVEL OF EVIDENCE

Level IV, therapeutic case series.

Bilateral test for potential subluxation of the DRUJ

Untreated distal radioulnar joint (DRUJ) instability can lead to arthritis of the DRUJ. To date, however, the clinical determination of DRUJ instability still represents a challenge. We developed a new clinical test to determine its stability. This works by directly observing the ulnar head's dynamic behavior during active pro-supination or testing the DRUJ's static stability at different grades of rotation. With the test results, the examiner gains a better understanding of the ulna head's behavior during rotational movements and how that compares to that of the uninjured side.

THE BEAUTY OF STABILITY: DISTAL RADIOULNAR JOINT STABILITY IN ARTHROSCOPIC TRIANGULAR FIBROCARTILAGE COMPLEX REPAIR

The triangular fibrocartilage complex (TFCC) has an important role in the stability of the distal radioulnar joint (DRUJ) stability. We designed a new method of TFCC tear repair that has satisfactory post-operative DRUJ stability. From May 2004 to August 2010, 14 patients who underwent this operation were reviewed. The average post-operative follow-up period was 8.2 months; 66.7% of the patients with TFCC tear in sigmoid notch had clinical DRUJ instability, while only 50% of tear in fovea and 16.7% of tear in base of ulnar styloid had clinical DRUJ instability. Transosseous suture via inside-outside technique was used for repair. At the final follow-up, all 14 patients have soft end point with < 5 mm translations of the DRUJ shown by the stress test. Based on this small sample with satisfactory outcome assessed by the Mayo modified wrist score and DRUJ stability, we recommend TFCC tear in sigmoid notch, which has a higher chance of DRUJ instability, to be repaired by transosseous suture.

Current innovations in wrist arthroscopy

It has become clear that the stability of the scapholunate joint does not depend wholly on the scapholunate interosseous ligament, but rather on both primary and secondary stabilizers, which form a scapholunate ligament complex. Each case of scapholunate instability is unique and should be treated with tissue-specific repairs, which may partly explain why one procedure cannot successfully restore joint stability in every case. Wrist arthroscopy has a pivotal role in both the assessment and treatment of the scapholunate ligament complex derangements. Tears of the foveal attachment of the triangular fibrocartilaginous complex can be an underdiagnosed cause of distal radioulnar joint instability, because the foveal fibers cannot be visualized using the standard radiocarpal arthroscopy portals. Distal radioulnar joint arthroscopy allows for direct visualization and assessment of these fibers, which in turn has spawned a number of open and arthroscopic repair methods. Wrist arthroscopy has gained wider acceptance as a method to fine-tune articular reduction during open and percutaneous fixation of distal radius fractures, and simplifies intra-articular osteotomies for malunion. It can facilitate percutaneous bone grafting of scaphoid nonunions and has a role in the diagnosis and treatment of associated soft tissue lesions. These and other recent developments will be discussed in the following article.