Distal Radioulnar Joint Instability: Assessment of Three Intraoperative Radiographic Stress Tests

Background: The purpose of this study is to describe three radiographic stress tests that could be used to examine for distal radioulnar joint (DRUJ) instability intraoperatively, and to determine their ability to detect DRUJ instability after sequentially sectioning the DRUJ. Methods: Eleven fresh frozen cadaveric upper extremities (mean age 52.6 ± 14.9 years) were obtained. We sequentially sectioned the DRUJ. After each component of the DRUJ was sectioned, we performed three radiographic stress tests—squeeze test, ulnar pull in coronal plane, and simulated DRUJ ballotment test. Results: The squeeze test detected a significant increase in diastasis relative to the intact DRUJ after sectioning of the foveal insertion of the triangular fibrocartilage complex (TFCC; 1.0 mm) and the distal oblique bundle (DOB; 1.2 mm). The ulnar pull test in the coronal plane detected a significant increase in diastasis relative to the intact DRUJ after sectioning of the dorsal and volar radioulnar ligaments (2 mm), the foveal insertion of the TFCC (2.6 mm), and the DOB (4.4 mm). The simulated DRUJ ballotment test detected a significant increase in dorsal translation of the ulna relative to the intact DRUJ with sectioning of the foveal insertion of the TFCC (4.9 mm) and the DOB (5.6 mm). Conclusion: The squeeze test and simulated DRUJ ballotment test detect a significant increase in diastasis after the foveal attachment of the TFCC was sectioned. The ulnar pull test in the coronal plane was the most sensitive test for detecting a significant increase in diastasis relative to the intact DRUJ.     

Editorial Commentary: Arthroscopic Capsular Repair of Wrist Triangular Fibrocartilage Complex Tears: Beware That Apparent Isolated Atzei Class 1 (Isolated Distal Component) Tears May Include a Proximal Component

Accumulating knowledge about the anatomy of the triangular fibrocartilage complex (TFCC) and its function has revealed that the foveal insertion of the TFCC plays a key role in distal radioulnar joint stability rather than the superficial fibers that insert into the ulnar styloid. Recently, the interest in torn peripheral TFCC repair has been shifting from capsular repair for Atzei class 1 to foveal repair for Atzei class 2 or 3. Most acute Atzei class 1 tears spontaneously heal without surgical repair; in contrast, in cases of sustained pain and distal radioulnar joint instability even after successful Atzei class 1 repair, the unrecognized proximal component TFCC tear concomitant with a distal component TFCC tear may exist and appropriate treatment for the proximal component TFCC tear should be combined. Although overall successful results have been reported using various repair techniques, the most important consideration is re-establishing biologic regeneration potential at the insertion site of torn TFCC.     

三角纤维软骨复合体解剖及生物力学研究

目的从解剖完整的腕关节入手,阐明三角纤维软骨复合体各组成部分的解剖特点,评估三角纤维软骨复合体(TFCC)对于维持远侧桡尺关节稳定的重要性。方法对8个新鲜解冻的腕关节和6个经甲醛浸泡的腕关节进行显微解剖。同时对影响远侧桡尺关节稳定性的因素作了初步的评估。前臂中旋位,垂直于尺骨予20N拉力下测量尺骨相对于桡骨的位移,然后先后切断掌背侧桡尺韧带,测量尺骨相对于桡骨的位移变化。结果发现掌背桡尺韧带由三角纤维软骨盘外周增厚而成,止于尺骨茎突基底部,是维持远侧桡尺关节稳定性的主要因素之一,切断掌背侧桡尺韧带会导致远侧桡尺关节明显不稳。结论TFCC由三角纤维软骨盘、掌背侧桡尺韧带、尺骨月骨韧带、尺骨三角骨韧带、尺侧腕伸肌下腱鞘、半月板同源物、尺侧囊组成。掌背桡尺韧带是维持远侧桡尺关节稳定性的主要因素之一,掌背侧桡尺韧带损伤会导致远侧桡尺关节明显不稳。     

Do triangular fibrocartilage complex foveal injuries affect the clinical outcome of ulnar shortening osteotomy for ulnar impaction syndrome?

BackgroundUlnar shortening osteotomy (USO), as its name implies, is used to shorten the ulna. It subsequently tightens the triangular fibrocartilage complex (TFCC) and ulnar wrist. TFCC foveal insertion is a primary stabilizer of the distal radioulnar joint. It is unclear whether USO is effective in TFCC foveal injuries. The purpose of this study was to review the clinical outcomes of ulnar shortening osteotomies with and without TFCC foveal injuries.MethodsWe retrospectively reviewed patients with ulnar wrist pain treated with USO and wrist arthroscopy including the distal radioulnar joint (DRUJ). Sixty-five patients were included in this study. An algorithm was used to guide surgical decision-making. After arthroscopic confirmation of ulnar impaction syndrome, we performed USO with a locking compression plate (mean length of shortening, 2.7 mm; range, 1–7.5 mm). The flattened TFCC disc due to ulnar shortening was confirmed arthroscopically. If the DRUJ was unstable after USO, we repaired the TFCC foveal insertion.ResultsThere were 32 post-traumatic and 33 idiopathic cases. We detected TFCC disc injuries in 34 wrists and TFCC foveal injuries in 33 wrists; both types were found in 15 wrists. TFCC foveal injuries were not significantly correlated with patient age, history of trauma, or clinical outcome. Most patients showed good clinical outcomes; 31 of 65 patients had preoperative DRUJ instability, with a significant number having foveal but not disc injuries.ConclusionUSO achieved reasonable outcomes, even in patients with TFCC foveal injuries. In cases demonstrating ulnar impaction, USO should be prioritized over TFCC repair.     

Arthroscopic evaluation of the foveal attachment of the triangular fibrocartilage

Anatomical and biomechanical studies have highlighted the importance of the deep attachment of the TFCC for maintaining stability of the distal radioulnar joint (DRUJ). The standard arthroscopic assessment of the TFCC does not allow one to definitively determine whether the deep fibers are indeed intact, and establishing the diagnosis of a foveal detachment remains an exacting challenge. DRUJ arthroscopy is useful to assess the foveal fibers in any patient with DRUJ instability and can aid in the surgical decision making.     

Editorial Commentary: In Cases of Concurrent Triangular Fibrocartilage Complex Tears and Ulnar Styloid Process Fracture Nonunions,We May Neither Need to Excise nor Repair the Ulnar Styloid Fracture Nonunion Fragment

The ulnar-sided wrist contains multiple potential pain generators that may present in isolation. Occasionally, however, wrist trauma results in multiple concurrent and overlapping injuries that make diagnosis and treatment of these conditions challenging. Deep/foveal tears of the triangular fibrocartilage complex (TFCC) may occur in the setting of nonunited ulnar styloid process fractures. Treatment of these injuries has historically included open TFCC repair with fixation or excision of the ulnar styloid fracture nonunion fragment; however, recent literature suggests that addressing the ulnar styloid nonunion fragment may not be as important as we think. Recent research shows that we may not need to excise or repair the ulnar styloid fracture nonunion fragment, which in turn may help preserve the complex ligamentous architecture that stabilizes the ulnar-sided wrist. One thing we know for sure is that foveal tears of the deep fibers of the TFCC, with or without ulnar styloid fracture (Palmer 1B, Atzei class 2 or 3), can produce distal radioulnar joint (DRUJ) instability and wrist dysfunction and should be addressed sooner rather than later to prevent long-term consequences, including DRUJ osteoarthritis. Whether you choose to approach the problem arthroscopically or open, the foveal TFCC tear should be repaired to prevent long-term sequalae.     

Arthroskopisch unterstützte ulnare Refixierung des TFCC mit Schraubanker

Objective

The goal of this operation technique is a stable refixation of the triangular fibrocartilage complex (TFCC) to the fovea ulnaris. The stability of the distal radio-ulnar joint (DRUJ) should be re-established. The patients pain and the feeling of instability should be reduced.

Indications

Lesions of the foveal component of the TFCC resulting in DRUJ instability. Combined lesions of both components of the TFCC. Complete detachment of the TFCC from the ulna either without fracture of the styloid process of the ulna or with fracture (floating styloid).

Contraindications

Severe lacerations of the TFCC and clinically relevant arthrosis of the DRUJ. Severely osteoporotic bone.

Surgical technique

Following diagnostic arthroscopy and performance of stability control of the TFCC with a palpation hook, reduction of the DRUJ with supination position of the wrist. Bone anchor fixation through the direct foveal portal (DF). Under arthroscopic control through the 3/4 portal, the suture from the DF portal is placed through the TFCC. Pull out and tie the strands through the 6 U portal.

Postoperative management

Restriction of rotation of the forearm in a Munster cast or special cast brace for 6 weeks. Self-controlled exercise of the wrist after 6 weeks. Physiotherapy and strength building 8 weeks postoperatively.

Results

Clinical studies of this technique showed a significant amelioration of pain perception, improved range of motion and DASH score in all patients after anchor fixation. The results are comparable to other techniques. All patients returned to work after the operation. Accordingly, using this technique a very good stabilization of the DRUJ with low complications can be achieved.

     

Biomechanical comparison of transosseous and capsular repair of peripheral triangular fibrocartilage tears

Purpose: The purpose of this study was to biomechanically compare the repair strength of peripheral triangular fibrocartilage complex (TFCC) repairs to the distal ulna using transosseous sutures (group I) versus TFCC repairs to the extensor carpi ulnaris tendon subsheath and surrounding dorsal capsule (group II). Type of Study: Cadaveric biomechanical study. Methods: Six matched pairs of fresh-frozen cadaveric upper extremities were procured. Each underwent the creation and repair of a peripheral, ulnar-sided detachment of the TFCC. Following stabilization of the humerus and radius, the maximum translations of the ulna in the dorsal and palmar directions were measured in response to an 8-lb traction load before disrupting the TFCC, after disrupting the TFCC, and after repairing the TFCC. Results: There was a significant increase in the total translation of the ulna following disruption of the TFCC (P <.001) in both groups. The mean and standard deviation of the percent total translation eliminated following TFCC repair for group I specimens (transosseous suture) were 33.8% and 11.6%, respectively. The mean and standard deviation of the percent total translation eliminated following TFCC repair for group II specimens (capsular implantation) were 59.3% and 29.7%, respectively. The observed difference between the repair groups is not significant (P =.157). Conclusions: While disruption of the TFCC does significantly increase distal radioulnar joint (DRUJ) instability and repair of the TFCC does significantly restore DRUJ stability, the results of this study do not show a significant biomechanical difference between the 2 TFCC repair techniques in a cadaveric model.Arthroscopy: The Journal of Arthroscopic and Related Surgery, Vol 19, No 4 (April), 2003: pp 391–396     

桡尺远侧关节稳定结构的生物力学分析

目的 从生物力学的角度分析桡尺远侧关节（distal radioulnar joint,DRUJ）稳定结构在前臂台的稳定作用及损伤后的临床体征。方法 用自身的实验架固定8侧新鲜上肢标本。分级切除桡尺远侧关节的主要稳定结构,进行生物力学测量分析。结果 三角纤维软骨复合体（triangular fibrocartilage complex,TFCC）水平部分前半段切除后,DRUJ于旋后位时不稳定;水平部分后半段切除后,DRUJ于旋前位是不稳定;TFCC水平部及远侧骨骨间膜全部切除后,DRUJ于各个位置均不稳定。结论 DRUJ的稳定性主要依靠TFCC水平部分和远侧骨间膜的维持。背侧桡尺韧带在前臂旋前位时,维持DRUJ的稳定作用较掌侧桡尺韧带大;相反,在旋后位时掌侧桡尺韧带比背侧桡尺韧带更为重要。     

Repair of foveal detachment of the triangular fibrocartilage complex: open and arthroscopic transosseous techniques

Because the radioulnar ligament attaches to the ulnar fovea and base of the ulnar styloid, foveal detachment of the triangular fibrocartilage complex (TFCC) induces severe distal radioulnar joint instability. This article describes both an arthroscopic and open repair technique to reattach the TFCC to the fovea. Both techniques reanchor the detached TFCC to the fovea. Both techniques are reliable and promising techniques in the repair of a foveal detachment of the TFCC.     

Distal radioulnar joint instability in distal radius fractures: the role of sigmoid notch and triangular fibrocartilage complex revisited

The stabilising effects of various structures of the distal radioulnar joint (DRUJ) have been heavily debated. This biomechanical cadaveric study examined the effects of the volar and dorsal lips of the sigmoid notch and the volar and dorsal aspects of the triangular fibrocartilage complex (TFCC) on DRUJ stability. Sequential fractures of the distal radius and sectioning of the TFCC were performed followed by measurements of ulnar translation with the forearm in pronation, neutral and supination. A dorsal lunate facet fracture created instability in pronation. Lunate facet fractures alone did not create instability in other forearm positions. Sectioning of the volar TFCC after loss of the dorsal TFCC by a dorsal lunate facet fracture caused DRUJ instability with the forearm in neutral position. Sectioning of the dorsal TFCC after loss of the volar TFCC due to a volar lunate facet fracture created instability in neutral and pronated positions.     

Ulnar-positive variance as a predictor of distal radioulnar joint ligament disruption

PURPOSE: Previous cadaveric data show that disruption of the triangular fibrocartilage complex (TFCC) at the wrist allows 0.5 to 3.0 mm of proximal radius migration. Anatomic studies have documented the presence of superficial and deep fibers of both the palmar and the dorsal distal radioulnar joint (DRUJ) ligaments. The aim of this study was to determine the contribution of the superficial and deep fibers of the DRUJ ligaments to longitudinal forearm stability as measured by ulnar-positive variance. METHODS: Eight fresh-frozen cadaver specimens were included in this study. Each specimen was secured with external fixation clamps to a sequential loading frame with the elbow in 90 degrees of flexion and the forearm and wrist in neutral pronation supination, neutral ulnar-radial deviation, and neutral volar-dorsal angulation. The radial head was resected and a force gauge was applied to the proximal radius. The peripheral TFCC was identified through an incision between the fifth and sixth extensor compartments and the dorsal capsulotomy of the DRUJ capsule. After baseline measurement sequential transection of the superficial and deep fibers of the TFCC was performed. Before and after each step load application and removal were performed by attaching an 88.90-N weight to the end of a force gauge and via longitudinal traction on the proximal part of the radius, and ulnar variance was measured with wrist fluoroscopy. RESULTS: Transection of the superficial TFCC fibers resulted in radius migration of 0.70 mm. This migration, however, was not significantly different from that observed at baseline. After both the superficial and deep TFCC fibers were transected the radius migrated proximately with load. This change of ulnar variance was significantly greater than that observed at baseline or after transection of only the superficial TFCC fibers. CONCLUSIONS: Traumatic injury to the TFCC with radiographic evidence of ulnar-positive variance may be an indication of disruption of the deep TFCC fibers.     

Peripheral tears of the triangular fibrocartilage complex cause distal radioulnar joint instability after distal radial fractures

The aim of this prospective study was to determine whether peripheral tears of the triangular fibrocartilage complex (TFCC) in patients younger than the osteoporotic age (males,<60 years; females, <50 years) were related to chronic distal radioulnar joint (DRUJ) instability. Fifty-one patients (27 women) with displaced distal radial fractures were included in the study. The median age was 41 years (range, 20-57 years). Arthroscopy at the time of fracture showed complete or partial TFCC tears in 43 patients (24 had only peripheral tears, 10 had only central perforations, and 9 had combined tears). The 1-year (range, 11-27 months) follow-up period included an interview, physical examination, and radiographic evaluation. Ten of the 11 patients with complete peripheral TFCC tears had DRUJ instability at the follow-up examination compared with 7 of the 32 patients with only partial or no peripheral tears. Patients with instability of the DRUJ had a worse Gartland and Werley wrist score. Instability was not associated with any radiographic finding either at the time of fracture or at the follow-up examination. Initial fracture or nonunion of the styloid was even slightly more common in stable patients.     

Intraoperative evaluation of DRUJ instability through dorsal stress radiography in distal radius fractures

IntroductionCertain type of injury of the triangular fibrocartilage complex associated with distal radius fracture can result in distal radioulnar joint instability (DRUJ). Untreated DRUJ instability may lead to poor result in the treatment of acute distal radius fractures. The aim of this study was to evaluate DRUJ instability in distal radius fractures through dorsal stress radiography comparing the affected and unaffected wrists intraoperatively.Materials and methods49 patients with a distal radius fracture who were operatively treated with a volar locking plate were included. Dorsal stress radiography was used to evaluate both affected and unaffected wrists peri-operatively to detect DRUJ instability. Under general anesthesia, a dorsal stress test was performed on the unaffected wrist. Additionally, after fixation of the affected wrist, a dorsal stress test was performed. The ulnar translation ratio (UTR) was measured through the dorsal stress radiograph. Arthroscopic examination was performed on all affected wrists according to Palmer's and Atzei classification.ResultsThe UTR of the affected wrist and the TFCC injury Palmer-type IB tendency were positively correlated (odds ratio: 1.18, p-value: 0.002). Additionally, as the UTR difference between the affected and unaffected wrists enlarged, it revealed a significant DRUJ instability tendency due to Palmer-type IB TFCC injury (p-value: 0.000006, Wilcoxon rank-sum test).ConclusionsDorsal stress radiography is a reliable, simple procedure to evaluate DRUJ instability intraoperatively. UTR value from dorsal stress radiography could be useful for evaluating DRUJ instability associated with distal radius fracture.     

Management of the distal radioulnar joint and ulnar styloid fracture

Fractures of the distal radius and ulnar styloid have the potential to disturb the normal function of the distal radioulnar joint (DRUJ), resulting in loss of motion, pain, arthritis, or instability. The DRUJ can be adversely affected by several mechanisms, including intra-articular injury with step-off, shortening, and angulation of an extra-articular fracture; injury to the radioulnar ligaments; ulnar styloid avulsion fracture; and injury of secondary soft tissue stabilizers. This article discusses the management of the DRUJ and ulnar styloid fracture in the presence of a distal radius fracture.     

Editorial Commentary: Guidelines for Wrist Triangular Fibrocartilage Complex Foveal Tears: A Compass for a Broad Voyage

The ulnar head attachment of triangular fibrocartilage complex is divided into 2 sections: the distal radioulnar ligament consists of superficial and deep bundles on both the palmar and dorsal sides, which attach at the fovea and the base of the ulnar styloid. A tear on the ulnar side of triangular fibrocartilage complex inevitably occurs at these attachments. Both magnetic resonance imaging and distal radioulnar joint (DRUJ) arthroscopy are crucial. DRUJ arthroscopy can clarify the tear location. An ulnar styloid tear can be treated by capsular repair. However, a foveal tear should be reattached to the fovea because this tear could cause gross DRUJ instability. There are several ways to reattach the bundles to the fovea, including single- or double-tunnel or bone anchors, and open versus arthroscopic.     

Influence of the pronator quadratus and supinator muscle load on DRUJ stability

PURPOSE: To determine the effects of altering the load contributions of the pronator quadratus and supinator muscles on in vitro distal radioulnar joint (DRUJ) stability during pronation and supination and before and after ulnar head excision. METHODS: Multiple pronation trials were conducted with incremental loading of the pronator quadratus relative to the pronator teres muscle; supination trials were similarly conducted with incremental loading of the supinator relative to the biceps muscle. All trials were conducted using an upper-limb apparatus capable of simulating muscle/tendon loading and displacement. Stability measurements included dorsal-volar translations of the radius relative to the ulna and DRUJ diastasis and convergence. RESULTS: Increased pronator quadratus loading did not affect intact DRUJ stability but effects were noted after ulnar head excision when the forearm was positioned between neutral and full pronation. Incremental loading of the supinator muscle did not modify DRUJ stability in the intact or ulnar head excised state. CONCLUSIONS: Pronator quadratus muscle activity aggravates forearm instability after ulnar head excision. Immobilization of the forearm in mid- to full supination should minimize pronator quadratus activity and optimize soft-tissue healing. This information may be useful to develop in vitro muscle-loading scenarios and analytical forearm models.     

Effects of peripheral tears of the triangular fibrocartilage complex on distal radioulnar joint stability: A biomechanical study

BackgroundPeripheral triangular fibrocartilage complex (TFCC) tears may induce instability of the distal radioulnar joint (DRUJ). In this biomechanical study, simulated peripheral tears of the TFCC were examined on the stability of the DRUJ. Restabilization effect of the DRUJ by ulnar shortening and direct repair of those injuries were sequentially examined.MethodThe DRUJ stiffness was measured in intact, simulated two types of peripheral tears (ulnar and extended ulnodorsal) at three forearm positions: neutral, 60° pronation and 60° supination in 8 fresh frozen cadaver specimens. After the tears were sutured with stitches or after simulated ulnar shortening of 3 mm, the DRUJ stiffness was again measured.ResultsThe ulnar and ulnodorsal TFCC tears decreased the DRUJ stiffness significantly compared with the intact in all forearm positions. When ulnar shortening was done for the ulnar tear, the DRUJ stiffness increased significantly in the neutral and 60° pronated positions. When the ulnar TFCC tear was repaired, the DRUJ stiffness increased significantly in all forearm positions. DRUJ stiffness did not increase either with ulnar shortening or repair in ulnodorsal tear of the TFCC, however.ConclusionThe simulated TFCC tears indicated significant loss of DRUJ stiffness. Direct repair or ulnar shortening was effective only on treatment of the ulnar tear of the TFCC in this study.     

MRI-Related Risk Factors for Distal Radioulnar Joint Instability

Objective

Instability of the dorsal radioulnar ligament (DRUL) is caused by multiple factors from bony and soft tissue structures. Studies of DRUJ instability based on MRI have rarely been reported. This study aims to investigate related instability factors in the distal radioulnar joint (DRUJ) after trauma based on MRI imaging.

Methods

The MRI imaging was performed on 121 post-traumatic patients with or without DRUJ instability from April 2021 to April 2022. All patients demonstrated pain or attenuated wrist ligamentous tissue quality with physical examination. The interesting variables, including age, sex, the distal radioulnar transverse shape, the triangular fibrocartilage complex (TFCC), DRUL, the volar radioulnar ligament (VRUL), distal interosseus membrane (DIOM), the extensor carpi ulnaris (ECU), and pronator quadratus (PQ), were analyzed using univariable and multivariable logistic regression model. The different variables were compared in radar plots and bar chart.

Results

An average age of 121 patients was 42.16 ± 16.07 years. The 50.4% DRUJ instability existed in all patients and the distal oblique bundle (DOB) presented in 20.7% of patients. The TFCC (p = 0.03), present DIOM (p = 0.001), and PQ (p = 0.006) were identified to be significant in final multivariable logistic model. The percentage of patients with ligament injuries were general higher in DRUJ instability group. The patients with absent DIOM had a higher rate in DRUJ instability, TFCC, and ECU injury. There was higher stability in shape of C-type, intact TFCC, and present DIOM.

Conclusion

DRUJ instability is closely associated with TFCC, DIOM, and PQ. It could provide a potential for early detection of potential instability risk and taking necessary preventive measures.     

TFCC reattachment after traumatic DRUJ instability: a simple alternative to arthroscopic management

With current trends favoring open reduction with internal fixation for distal radius fractures, distal radius-ulnar joint instabilities that were once clinically silent as a result of prolonged immobilization are now being recognized as a significant cause of morbidity. Arthroscopic management has proven to be both an effective and technically challenging treatment for triangular fibrocartilage complex (TFCC) tears. TFCC reattachment offers a safe, reproducible means of managing acute posttraumatic distal radioulnar join (DRUJ) instability after distal radius volar plating. With this technique, 30 patients at an average of 43 months were examined for continued DRUJ instability, range of motion, and radiographic evaluation for radius union, posttraumatic DRUJ arthritis, and hardware failure. Postoperative Gartland scores showed 88.6% excellent, 5.7% good, and 5.7% fair results. We conclude TFCC reattachment is a safe and effective alternative for treatment of acute DRUJ instability after open reduction with internal fixation of the distal radius, especially when equipment or experience does not support arthroscopic treatment.