Triangular fibrocartilage injury: a laboratory model

Advances in wrist arthroscopic surgery in Indonesia

Since the 1990s, new insights in wrist arthroscopy have led to the introduction of numerous treatment methods. Consequently, therapeutic procedures are no longer limited to resection as more specialized repair and functional reconstruction methods, involving tissue replacement and essential structural augmentation, have been shown to be beneficial. This article discusses the most prevalent reasons and uses for wrist arthroscopy, with an emphasis on Indonesia’s most recent and major advances in reconstructive arthroscopic surgery. Joint debridement, synovectomy, ganglionectomy, capsular release, and osteotomies are frequent resection operations. Ligament repair and arthroscopy-aided reduction and fixation for fractures and nonunion are all examples of reconstructive surgery.

Extensor Retinaculum Reconstruction of the Distal Radioulnar Joint in Adolescents

BACKGROUND

This study characterizes the outcomes and complications of surgical reconstruction of distal radioulnar joint (DRUJ) instability using the extensor retinaculum (Herbert sling). Our hypothesis was that extensor retinaculum reconstruction is a reliable method of DRUJ stabilization in adolescents.

METHODS

This was a retrospective study of pediatric patients treated surgically using the Herbert sling for DRUJ instability at a single institution. We identified 22 subjects who underwent surgery at an average of 16.2 years of age (range, 12-18 years). Medical records and available imaging were reviewed for all subjects, and patients were contacted to participate in the prospective completion of the Quick Disabilities of the Arm, Shoulder, and Hand (QuickDASH) questionnaire.

RESULTS

Preoperative symptoms were more commonly pain (95%) than feelings of DRUJ instability (45%), although 100% had instability on physical examination. Eight (36%) patients demonstrated limited supination preoperatively. Twenty-one subjects (95%) noted prior injury to that wrist, 15 of which were distal radius fractures. Surgery consisted of stabilization of the DRUJ using extensor retinaculum, in concert with other procedures to address all potential causes of wrist pain. Postoperatively, DRUJ stability was maintained in 21 of 22 subjects. Of the 12 patients who provided functional outcome scores, median QuickDASH score was 7.6 (range, 0-45).

CONCLUSIONS

Distal radioulnar joint instability in adolescents is often preceded by fracture of the distal radius. Surgeons must maintain a high level of suspicion to appropriately diagnose DRUJ instability, which is often not an isolated pathoanatomical problem. The Herbert sling technique using extensor retinaculum can successfully confer DRUJ stability in this population.

Chronic Posttraumatic Instability of the Distal Radioulnar Joint: Foveal Reattachment of the Triangular Fibrocartilage Complex With Dorsal Capsuloplasty and Extensor Retinaculum Imbrications

Background: The purpose of this article is to describe the surgical technique used by the authors and the outcome in the treatment of chronic posttraumatic instability of the distal radioulnar joint (DRUJ). Methods: A retrospective study was conducted analyzing the medical records of 11 patients with chronic posttraumatic instability of the DRUJ, treated by a foveal reattachment of the triangular fibrocartilage complex with dorsal capsular and extensor retinaculum imbrications between 2016 and 2017, with a follow-up evaluation of 1 year. Results: All patients reported pain relief and the absence of instability, returning to normal activities in 3 to 6 months. Disabilities of the Arm, Shoulder, and Hand (DASH) questionnaire ranged from 2 to 25, resulting in a mean score of 9.5. Forearm rotation averaged 89° of pronation and 85° of supination. Conclusion: Foveal reattachment of the triangular fibrocartilage complex with dorsal capsular and extensor retinaculum imbrications is an effective surgical procedure for the treatment of DRUJ chronic posttraumatic instability.

Distal Radioulnar Joint Instability and Associated Injuries: A Literature Review

The distal radioulnar joint (DRUJ) allows supination and pronation of the distal forearm and wrist, an integral motion in everyday human activity. DRUJ injury and chronic instability can be a significant source of morbidity in patients' lives. Although often linked with distal radius fractures, DRUJ injury may occur in a variety of other upper extremity injuries, as well as an isolated pathology. Diagnosis of this injury requires the clinician to have a high index of suspicion and low threshold for clinical testing and further imaging of the DRUJ. The purpose of this article is to provide a review on DRUJ anatomy and biomechanics, to discuss common diagnostic and treatment modalities, and to identify common injuries associated with DRUJ instability.

Relationship between Fracture of the Ulnar Styloid Process and DRUJ Instability: A Biomechanical Study

Background  There has been clinical question in the treatment of ulnar styloid fracture with distal radius fracture, surgical fixation of the styloid fragment, or ignorance of the fragment. We examined relationship between size of the ulnar styloid fracture and distal radioulnar joint (DRUJ) stability biomechanically to answer the above clinical question. Methods  Changes in the dorsopalmar stiffness of the DRUJ after experimentally simulating in four types of ulnar styloid fractures were examined in cadavers. After tip, middle, base-horizontal, and base-oblique type of styloid fractures were made sequentially, changes in dorsopalmar DRUJ stiffness were measured using the MTS machine in the intact wrist, for each fracture, at 60 degrees pronation, neutral, and 60 degrees supination, respectively. Additional cutting of the radioulnar ligament (RUL) at the fovea was also simulated with the base-horizontal fracture. Results  The tip and middle type fractures did not demonstrate significant loss of stiffness compared with the intact. The base-horizontal fracture demonstrated only significant loss of stiffness in the dorsal direction (radius palmar; ulnar dorsal) with forearm in neutral rotation. The base-oblique fracture demonstrated significant loss of dorsopalmar stiffness of the DRUJ. Additional section of the RUL with the base-horizontal fracture induced significant loss of stiffness of the DRUJ compared with the intact. Conclusions  Because the RUL originates from the fovea as well as from the base of the ulnar styloid, these results suggest that DRUJ instability closely correlates with how much of the bony fragment includes the originating portions of the RUL. The findings further suggest that larger base-oblique and base-horizontal fragments with resultant DRUJ instability must be reattached, but that even base-horizontal fragment as well as tip and middle ulnar styloid fragment can be ignored when there is no instability.

Ulnar-Side Wrist Pain Management Guidelines: All That Hurts is Not the TFCC!

BACKGROUND

Ulnar-sided wrist pain is a common clinical problem, most often misdiagnosed as triangular fibrocartilage complex (TFCC) injury. It may be frustrating to the patient, as one may end up wearing a wrist splint for an unusually long period, disrupting their routine.

PURPOSE

Because of the dilemmas in the diagnosing the cause of ulnar-sided wrist pain, various algorithms have been suggested but it is an individual's choice to do a systematic assessment and follow in their routine clinical practice. We propose the 'storey concept' for examining the ulnar side of the wrist, with ulnar styloid as the reference point. The lower storey identifies the pathologies of the DRUJ, the intermediate storey identifies the pathologies of the radiocarpal joint and the upper storey identifies the pathologies of midcarpal and carpometacarpal joint.

CONCLUSION

Also, it is important to ramify the cause of pain into stable or unstable wrist, with or without arthritis, as this will guide us in managing the pain arising from distal radioulnar joint. In addition to methodical clinical examination, ideal radiographs and high-resolution MRI are critical to diagnose wrist pathologies. The role of wrist arthroscopy has consistently increased, and complements in both diagnosis and treatment of wrist pain especially in ambiguous situations.

Association between bone mineral density and ulnar styloid fracture in older Japanese adults with low-energy distal radius fracture

We investigated the association of the ulnar styloid fracture (USF) with the bone mineral status and fractured radial displacement in elderly patients. The presence of USF correlates with decreased BMD and severe displacement of the radius. These findings are helpful in treating osteoporosis to prevent subsequent fragility fracture.

PURPOSE

The pathogenesis of ulnar styloid fracture (USF), which often occurs with distal radius fracture (DRF), is unclear. This study aimed to investigate whether USF concomitant with low-energy DRF was associated with the bone mineral status and the degree of radiographically observed pretreatment radius displacement in Japanese adults above 50 years of age.

METHODS

The study subjects were 45 (44 female, 1 male) consecutive patients aged > 50 years with DRF caused by falls from June 2015 to May 2016. Fractures due to high-energy injuries were excluded. Patients were divided into two groups according to the presence or absence of USF. Radius displacement was assessed on anteroposterior and lateral radiographs by measuring ulnar variance, radial inclination, and volar tilt at initial examination before manual reduction of the bone. Bone mineral density (BMD) of the lumbar spine, femoral neck, and distal radius was also measured by dual-energy X-ray absorptiometry within 1 week of injury.

RESULTS

Significant differences in the BMD values of femoral neck, ulnar variance, radial inclination, and volar tilt were found between patients with USF and those without USF (all comparisons, p < 0.05). Logistic regression analysis of all subject data identified that volar tilt was significantly associated with the presence of USF (p = 0.048).

CONCLUSIONS

The presence of USF in low-energy DRF correlates with the decreased BMD of femoral neck and severe displacement of radius in elderly patients. These findings are helpful for the treatment of osteoporosis to prevent subsequent fragility fracture.

Modification of the use of the extensor retinaculum for reducible distal radioulnar joint instability: technique and results

Different surgical techniques have been described for chronic distal radioulnar joint instability: they are often complicated, quite invasive and may not be recommended for bidirectional instability. We describe a procedure using a radial-based extensor retinaculum strip and a capsular plication. This is a simple technique and less invasive than 'anatomic' radioulnar ligament reconstructions. We report the results of 38 patients (38 wrists) who we treated. After a minimum of 8 months we quantified the outcomes of the patients objectively by assessing ranges of motion, grip strength and clinical assessment of stability, and subjectively using questionnaires. Overall, 36 out of 38 patients were stable after surgery. The operated forearm and wrist had approximately 3° less range of motion in all planes and 3 kgf less grip strength compared with the unoperated side. The median Mayo modified wrist score was 90; the median visual analogue scale score was 2. This surgical technique appears to successfully treat patients with chronic reducible distal radioulnar joint instability. Anatomic reconstruction of both radioulnar ligaments is not always necessary.

LEVEL OF EVIDENCE

IV.

The Shape of the Triangular Fibrocartilage During Pronation–Supination

We studied the changes in the shape of the triangular fibrocatilage (TFC: disc proper) which occur during forearm rotation in disarticulated and articulated wrists. The influence of artificial 3 mm ulnar lengthening on distortion of the disc was also examined. In the disarticulated wrists, slight distortion of the central and radial portions of the TFC was observed in the ulnar neutral variance specimens. More distortion was noted in the radial and central portions of the TFC in specimens with positive ulnar variance or with the ulna lengthened. However, in the articulated wrist, the TFC demonstrated little change in shape during pronosupination even in the ulnar positive variance wrists or with the ulna lengthened. There was no significant change in palmar and dorsal peripheral lengths of the TFC in ulnar neutral, ulnar positive or ulna-lengthened specimens at three rotatory positions of the forearm. These findings suggest that changes in ulnar variance which occur during forearm rotation can produce distortion on the TFC, but the carpus helps to maintain the shape of the TFC during pronation–supination, even with positive ulnar variance.

Ulnar styloid process nonunion and outcome in patients with a distal radius fracture: a meta-analysis of comparative clinical trials

PURPOSE

There is no consensus on the relation between ulnar styloid process nonunion and outcome in patients with distal radius fractures. The aim of this study was to analyze whether patient-reported outcome is influenced by the nonunion of the accompanying ulnar styloid fracture in distal radius fracture patients.

METHODS

A meta-analysis of published studies comparing outcomes after distal radius fractures with a united versus a non-united ulnar styloid process was performed. In addition, if provided by the authors, the raw data of these studies were pooled and analysed as one study. The outcome measures of the analyses included patient-reported outcome, functional outcome, grip-strength, pain, and distal radioulnar joint (DRUJ) instability.

RESULTS

Data from six comparative studies were included, concerning 365 patients with a distal radius fracture. One hundred and thirty-five patients with an ulnar styloid union were compared with 230 patients with a nonunion of the ulnar styloid. No significant differences were found between groups regarding any outcome measure.

CONCLUSION

Based on this meta-analysis, there is no relation between the nonunion of the ulnar styloid process and function in patients with a distal radius fracture.

Anatomical transosseous fixation of the deep and superficial fibers of the radioulnar ligaments

INTRODUCTION

The triangular fibrocartilage complex is in conjunction with the interosseous membrane the most important stabilizer of the distal radioulnar joint. Lesions of the triangular fibrocartilage complex may cause instability of the distal radioulnar joint with serious consequences. Therefore, the goal is to reconstruct and provide stability to prevent further harm.

SURGICAL TECHNIQUE

Based on the anatomical configuration of the radioulnar ligaments, we present a technique which addresses both the deep and the superficial fibers of the radioulnar ligaments. This surgical procedure can be performed either openly or arthroscopically assisted. Two osseous 2-mm tunnels starting from the ulnar neck to the foveal surface are created. A nonabsorbable suture is passed through the tunnels and the triangular fibrocartilage using a 20-gauge venipuncture needle in order to attach the deep fibers. Then a third osseous tunnel starting from the lateral base of the styloid process to the medial aspect is created. The suture is passed through this tunnel and through the triangular fibrocartilage and around the styloid process palmarily using the same needle as before in order to anchor the superficial fibers anatomically. After reducing the ulna head the sutures are tightened.

CONCLUSION

This technique is quite simple and addresses the anatomical configuration of the radioulnar ligaments.

Midterm functional outcome after dorsal capsular imbrication for posttraumatic instability of the distal radioulnar joint

INTRODUCTION

The dorsal capsular imbrication of the distal radioulnar joint (DRUJ) which was performed because of posttraumatic dorsal instability showed promising functional results after the first postoperative years. Therefore, we hypothesized that patients after capsular imbrication are characterized by good subjective and functional outcome measurements after a midterm period.

MATERIALS AND METHODS

Eleven patients (range 21-50 years of age; median 35 years of age) were examined after capsular imbrication of the DRUJ because of posttraumatic instability with a mean follow-up time of 72 months (range 46-114 months; median 66 months). Examination parameters included the determination of range of motion (ROM), grip strength, pain and functional outcome scores (modified Mayo wrist score (MMWS); Disabilities of the Arm, Shoulder and Hand questionnaire (DASH score)).

RESULTS

A mean DASH score of 6.7 (range 0-22.5) and mean MMWS of 91.8 (range 75-100) were measured. Grip strength reached 96.7 % of the contralateral hand. Range of motion reached at least 93.1 % of the contralateral hand. Eight of 11 patients regarded functional outcome and pain reduction as excellent. Six of 11 patients did not recognize a diagnosed instability of DRUJ as such. Ulnar-sided wrist pain was the apparent symptom in these cases.

CONCLUSIONS

Capsular imbrication of the DRUJ is a reliable and sufficient treatment option in case of posttraumatic dorsal instability. Since DRUJ instability is seldom recognized by the patients as such, a standardised diagnostic algorithm is mandatory to guarantee reliability and efficacy for identifying DRUJ instability.

Impact of ulnar styloid fractures in nonoperatively treated distal radius fractures

PURPOSE

The effect of an ulnar styloid fracture (USF) on the stability of nonoperatively treated distal radius fractures (DRF) is unknown. The aim of this study was to evaluate the influence of USFs on the dislocation of DRFs treated by closed reduction.

METHODS

Standardized radiographs of 100 nonoperatively treated DRFs were evaluated. DRFs with a USF were compared to DRFs without a USF with respect to dorsal tilt, radial inclination, and ulnar variance.

RESULTS

We evaluated the radiographs of 100 DRFs in 99 consecutive patients, of whom 84 were women. An accompanying USF was present in 58 wrists, of which 49 were displaced. On the trauma radiograph, the USF group showed significantly more overall dislocation. After closed reduction, fracture position improved, and no significant differences in dislocation were observed between groups. After a mean of 42 days, radial inclination significantly decreased if a USF was present. When USF displacement was taken into account, significantly more ulnar variance occurred in the displaced USF group on the trauma and follow-up radiograph compared to the nondisplaced USF group and no-USF group.

CONCLUSIONS

The results of this study show that presence of a dislocated USF in patients with a DRF is associated with a worse position directly after trauma, and with recurrence of radial shortening after adequate reduction. These results warrant early radiologic follow-up in patients with reduced combined DRFs and USFs in order to evaluate the redislocation of the distal radius. Early detection of redislocation in these combined fractures may induce early surgical intervention.

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.

Capsular imbrication for posttraumatic instability of the distal radioulnar joint

PURPOSE

To analyze functional and subjective outcomes of patients with posttraumatic dorsal instability of the distal radioulnar joint (DRUJ) treated by a dorsal capsular imbrication.

METHODS

We reviewed 11 patients (7 men and 4 women) with posttraumatic instability of the DRUJ who were treated by a capsular imbrication. The patients ranged in age from 18 to 48 years (average, 33 y). The duration of symptoms before surgery ranged from 3 weeks to 6 months (average, 5 mo). We evaluated subjective outcome measurements such as the Disabilities of the Arm, Shoulder, and Hand (DASH) questionnaire, questions regarding symptoms of pain and instability, and overall satisfaction. Objective outcome measurements were physical examination, standard radiographs, and a review of any surgical complications. Patients were asked whether they experienced wrist tenderness with applied pressure, swelling, scar sensitivity, or pain. We determined functional outcome using the Modified Mayo Wrist Score including range of motion and grip strength. The score was used to evaluate the surgical technique and enable comparison with other surgical methods used to treat instability of the DRUJ.

RESULTS

After surgery, the total mean DASH score was 15 points. Range of motion, grip strength, pain, and overall function resulted in a mean Modified Mayo Wrist Score of 88 points, and therefore a good functional outcome. Three patients were noted to have persistent mild DRUJ instability on the stress test but did not have symptoms. The only intraoperative or postoperative complications observed were transient paresthesias on the ulnar side of the hand.

CONCLUSIONS

Capsular imbrication for posttraumatic instability of the DRUJ is a highly effective procedure with few complications and good functional and subjective results even in cases with concomitant healed fractures of the radius or ulnar styloid.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic IV.

Pathomechanisms of ulnar ligament lesions of the wrist in a cadaveric distal radius fracture model

BACKGROUND AND PURPOSE

Mechanisms of injury to ulnar-sided ligaments (stabilizing the distal radioulnar joint and the ulna to the carpus) associated with dorsally displaced distal radius fractures are poorly described. We investigated the injury patterns in a human cadaver fracture model.

METHODS

Fresh frozen human cadaver arms were used. A dorsal open-wedge osteotomy was performed in the distal radius. In 8 specimens, pressure was applied to the palm with the wrist in dorsiflexion and ulnar-sided stabilizing structures subsequently severed. Dorsal angulation was measured on digitized radiographs. In 8 other specimens, the triangular fibrocartilage complex (TFCC) was forced into rupture by axially loading the forearm with the wrist in dorsiflexion. The ulnar side was dissected and injuries were recorded.

RESULTS

Intact ulnar soft tissues limited the dorsal angulation of the distal radius fragment to a median of 32(o) (16-34). A combination of bending and shearing of the distal radius fragment was needed to create TFCC injuries. Both palmar and dorsal injuries were observed simultaneously in 6 of 8 specimens.

INTERPRETATION

A TFCC injury can be expected when dorsal angulation of a distal radius fracture exceeds 32(o). The extensor carpi ulnaris subsheath may be a functionally integral part of the TFCC. Both dorsal and palmar structures can tear simultaneously. These findings may have implications for reconstruction of ulnar sided soft tissue injuries.

Open repair of foveal avulsion of the triangular fibrocartilage complex and comparison by types of injury mechanism

PURPOSE

Little attention has been paid to injury mechanisms of foveal avulsion of the triangular fibrocartilage complex (TFCC). The purpose of this study was to determine whether the mechanism of injury is associated with different anatomic disruptions as well as different preoperative clinical symptoms. We also evaluated the clinical results of an open repair method for foveal avulsion according to the mechanism of injury.

METHODS

Fifteen patients with a traumatic foveal TFCC avulsion were treated with an open repair technique. The injury mechanism was forced wrist extension in 10 patients (group E) and forced forearm rotation in 5 patients (group R). All patients in group E and 3 in group R showed positive fovea signs. Surgical and clinical findings were compared according to the 2 types of injury mechanism.

RESULTS

Foveal insertions of TFCC were found in surgery to be disrupted in all 15 patients. In addition, disruption of the dorsal styloid insertions of the radioulnar ligament showed a significantly greater association with group R than with group E. Clinical results showed significant postoperative improvement but were marginally different between the 2 groups.

CONCLUSIONS

The most common mechanism of foveal TFCC avulsions is forced wrist extension, an injury that commonly shows positive fovea signs and leaves the dorsal styloid insertion of the radioulnar ligament intact. Forced forearm rotation is the second most common injury mechanism that is more frequently associated with disruption of the dorsal styloid insertion.

TYPE OF STUDY/LEVEL OF EVIDENCE

Prognostic IV.

Acute dislocations of the distal radioulnar joint and distal ulna fractures

This article reviews acute dislocations of the distal radioulnar joint (DRUJ) and distal ulna fractures. Acute dislocations can occur in isolation or in association with a fracture to the distal radius, radial metadiaphysis (Galeazzi fracture), or radial head (Essex-Lopresti injury). Distal ulna fractures may occur in isolation or in combination with a distal radius fracture. Both injury patterns are associated with high energy. Outcomes are predicated on anatomic reduction and restoration of the stability of the DRUJ.

Molecular mechanisms of cartilage remodelling in osteoarthritis

Osteoarthritis (OA) is a degenerative joint disease that is characterized primarily by progressive breakdown of articular cartilage. The loss of proteoglycans, the mineralization of the extracellular matrix (ECM) and the hypertrophic differentiation of the chondrocytes constitute hallmarks of the disease. The pathogenesis of OA includes several pathways, which in single are very well investigated and partly understood, but in their complex interplay remain mainly unclear. This review summarises recent data on the underlying mechanisms, specifically with respect to cell-matrix interactions and cartilage mineralization. It points out why these findings are of importance for future OA research and for the development of novel therapeutic strategies to treat OA.

Change in the length of the ulnocarpal ligaments during radiocarpal motion: possible impact on triangular fibrocartilage complex foveal tears

PURPOSE

The fovea of the ulnar head is the primary attachment site for both the distal radioulnar and the ulnocarpal ligaments. Thus, both ligaments should be simultaneously affected by the traumatic avulsion of the triangular fibrocartilage complex from its ulnar attachment. Little attention, however, has been directed toward the role of the ulnocarpal ligaments in the mechanics of this type of injury. The purpose of this study was to investigate the changes in length of the ulnocarpal ligaments during various radiocarpal motions and to determine the type of radiocarpal motion that makes the ulnocarpal ligament taut and that could cause foveal avulsion if it were excessive.

METHODS

The 3-dimensional kinematics of the wrist joint were investigated noninvasively using a markerless bone registration technique in vivo. Magnetic resonance images of the wrists of 15 healthy volunteers were acquired in at least 5 positions during each wrist flexion-extension motion, radioulnar deviation, or the so called dart-throwing motion (radial extension-ulnar flexion motion). The 3-dimensional ligament paths of the ulnotriquetral, ulnolunate, ulnocapitate, and palmar radioulnar ligaments were modeled as the shortest paths between the fovea and the insertion point of each ligament. Changes in the 3-dimensional ligament length of each ligament between the neutral position and each wrist position were then calculated.

RESULTS

The lengths of the ulnotriquetral and ulnocapitate ligaments increased the most on wrist radial extension, and the length of the ulnolunate ligament increased the most on wrist extension. The length of the palmar radioulnar ligament changed minimally during any motion.

CONCLUSIONS

The ulnocarpal ligaments are likely to be stretched tensely in wrist radial extension and wrist extension. This study supports the hypothesis that one of the mechanisms responsible for a triangular fibrocartilage complex foveal tear is excessive traction of the ulnocarpal ligament caused by a fall on the outstretched hand.

The value of plain X-rays in predicting TFCC injury after distal radial fractures

In this prospective study, the plain X-rays and MRI scans of 60 patients with intraarticular distal radius fractures were examined in random order. MRI evaluation revealed that 27 of the 60 patients (45%) had triangular fibrocartilage lesions. No correlation was found between triangular fibrocartilage injury and the Melone classification system, the presence of an ulnar styloid fracture, comminution of the articular surface of the distal radius, >20 degrees dorsal angulation of the distal radius or subluxation/dislocation of the distal radioulnar joint on the plain X-rays. When Frykman Type VI and VIII fractures were compared with all the other Frykman subtypes, a significant difference in the incidence of triangular fibrocartilage complex tears was observed. We conclude that triangular fibrocartilage injury should be considered with all distal radial fractures, especially the Frykman Types VI and VIII.

Reconstruction for DRUJ instability

The skeletal architecture of the DRUJ provides minimal inherent stability, as the sigmoid notch is shallow and its radius of curvature is 50% greater than that of the ulnar head [Af Ekenstam F, Hagert CG. Anatomical studies on the geometry and stability of the distal radio ulnar joint. Scand J Plast Reconstr Surg 1985;19(1):17-25]. Due to its incongruent articulation, the DRUJ relies strongly on the surrounding soft tissues for stability. The triangular fibrocartilage complex (TFCC) is generally accepted as the major soft tissue stabilizer of the DRUJ of which the volar and dorsal radioulnar ligaments are the primary components. Restoration of the radioulnar ligaments offers the best possibility to restore the normal DRUJ primary constraints and kinematics. This article presents an update of the procedure developed by the senior author that anatomically reconstructs the palmar and dorsal radioulnar ligaments at their anatomic origins and insertions.

An immunohistochemical study of the triangular fibrocartilage complex of the wrist: regional variations in cartilage phenotype

The triangular fibrocartilage complex (TFCC) transmits load from the wrist to the ulna and stabilizes the distal radioulnar joint. Damage to it is a major cause of wrist pain. Although its basic structure is well established, little is known of its molecular composition. We have analysed the immunohistochemical labelling pattern of the extracellular matrix of the articular disc and the meniscal homologue of the TFCC in nine elderly individuals (age range 69-96 years), using a panel of monoclonal antibodies directed against collagens, glycosaminoglycans, proteoglycans and cartilage oligomeric matrix protein (COMP). Although many of the molecules (types I, III and VI collagen, chondroitin 4 sulphate, dermatan sulphate and keratan sulphate, the oversulphated epitope of chondroitin 6 sulphate, versican and COMP) were found in all parts of the TFCC, aggrecan, link protein and type II collagen were restricted to the articular disc and to entheses. They were thus not a feature of the meniscal homologue. The shift in tissue phenotype within the TFCC, from a fibrocartilaginous articular disc to a more fibrous meniscal homologue, correlates with biomechanical data suggesting that the radial region is stiff and subject to considerable stress concentration. The presence of aggrecan, link protein and type II collagen in the articular disc could explain why the TFCC is destroyed in rheumatoid arthritis, given that it has been suggested that autoimmunity to these antigens results in the destruction of articular cartilage. The differential distribution of aggrecan within the TFCC is likely to be reflected by regional differences in water content and mobility on the radial and ulnar side. This needs to be taken into account in the design of improved MRI protocols for visualizing this ulnocarpal complex of the wrist.

The "ulnar fovea sign" for defining ulnar wrist pain: an analysis of sensitivity and specificity

PURPOSE

Eliciting tenderness in the region of the ulnar fovea is a possibly useful clinical test for defining the source of ulnar-sided wrist pain. Until now, no reports of the clinical sensitivity and specificity of this test have been available. Based on anecdotal observations, a hypothesis was developed stating that ulnar fovea tenderness (positive "ulnar fovea sign") is sensitive and specific in detecting two ulnar-sided wrist conditions: foveal disruption of the distal radioulnar ligaments and ulnotriquetral (UT) ligament injuries.

METHODS

The clinical records of 272 consecutive patients with wrist arthroscopy performed by the senior author from 1998 through to 2005 were reviewed. Relevant clinical and surgical data were abstracted. The ulnar fovea sign test is executed by pressing the examiner's thumb distally into the interval between the ulnar styloid process and flexor carpi ulnaris tendon, between the volar surface of the ulnar head and the pisiform. A positive ulnar fovea sign is designated when there is exquisite tenderness that the patient claims replicates their pain, with comparisons made with the contralateral side.

RESULTS

There were a total of 90 foveal disruptions and 68 UT ligament injuries diagnosed during wrist arthroscopy. The ulnar fovea sign was positive in 156 patients. The sensitivity of the fovea sign in detecting foveal disruptions and/or UT ligament injuries was 95.2%. Its specificity was 86.5%.

CONCLUSIONS

The hypothesis stating that the ulnar fovea sign is a useful clinical maneuver to detect foveal disruptions and UT ligament tears is supported. The conditions represent 2 common sources of ulnar-sided wrist pain. The differentiation between the 2 conditions may be made clinically, where UT ligament tears are typically associated with a stable distal radioulnar joint and foveal disruptions are typically associated with an unstable distal radioulnar joint.

TYPE OF STUDY/LEVEL OF EVIDENCE

Diagnostic II.

Distal radioulnar joint arthroscopy and the volar ulnar portal

Pain on the ulnar side of the wrist remains poorly understood. As attention has shifted toward the myriad causes of ulnar-sided wrist pain, the utility of viewing the wrist from a volar ulnar (VU) perspective has emerged. Lunotriquetral ligament tears have been implicated in the pathogenesis of volar intercalated segmental instabilities. They often originate in the palmar subregion, which is most important for maintaining stability. These tears are difficult to visualize through the 4, 5, or 6R portals. They are well seen through a VU portal, and the direct line of sight facilitates debridement. The VU portal has potential use in the arthroscopic diagnosis and treatment of patients with injuries to the ulnar sling mechanism. It aids in triangular fibrocartilage repairs especially those involving the dorsal aspect between the ulnar styloid and the radial insertion, because the proximity of the 4, 5, and 6R portals makes triangulation of the instruments difficult. Although arthroscopy of the dorsal aspect of the distal radioulnar joint has been well described, it has largely remained a curiosity, with few clinical indications. Recent biomechanical studies have highlighted the importance of the deep attachment of the triangular fibrocartilage complex in maintaining distal radioulnar joint stability. The volar distal radioulnar portal is useful for assessing the foveal attachment. It may be used where there is the suspicion of a peripheral triangular fibrocartilage detachment due to a loss of its normal tension despite the lack of a visible tear during radiocarpal arthroscopy. The judicious use of these portals deserves consideration for inclusion as part of a thorough arthroscopic examination of selected patients with ulnar-sided wrist pain.

Relative contributions of the ulnar attachments of the triangular fibrocartilage complex to the dynamic stability of the distal radioulnar joint

PURPOSE

Laboratory studies evaluating the importance of the stabilizing structures of the distal radioulnar joint (DRUJ) largely have been limited to static design. Clinically, dynamic loading seems to be an important component of DRUJ instability. This study was designed to evaluate the influence of dynamic loading on the stability of the DRUJ with foveal versus styloid triangular fibrocartilage complex (TFCC) disruptions in a laboratory setting.

METHODS

Twelve fresh-frozen cadaveric upper-extremity specimens were tested using a dynamic simulator to study the contributions of the 2 ulnar insertions of the TFCC to the dynamic stability of the DRUJ. The specimens were tested in 3 loading conditions (no load, agonist loading, antagonist loading) in 3 different states of the TFCC (intact, foveal disruption, styloid disruption).

RESULTS

Without load no significant differences were found for the different conditions of the TFCC. Under loaded conditions the foveal insertion had a greater effect on stability than did the styloid insertion. Under agonist loading significant differences were found during supinating and pronating motions. With antagonist loading a significant difference was found only during supination.

CONCLUSIONS

The study results support the clinical impression that dynamic loading is an important component of DRUJ instability and that disruption of the foveal TFCC insertion into the foveal region of the distal ulna can produce instability.

Distal radius fractures: a comparison of tension band wiring versus ulnar outrigger external fixation for the management of distal radioulnar instability

PURPOSE

To retrospectively compare the results of immobilization of the forearm in supination with the results of tension band fixation of the ulnar styloid in 35 patients with distal radius fractures, fracture of the base of the ulnar styloid, and distal radioulnar joint instability treated with external fixation.

METHODS

Thirty-five patients with fractures of the distal radius, fracture of the base of the ulnar styloid, and unstable distal radioulnar joint had external fixation with adjunctive percutaneous pins and allograft bone to reduce and stabilize the distal radius fracture anatomically. Only those patients with an associated ulnar styloid base fracture displaced over 2 mm with gross distal radioulnar joint instability relative to the contralateral wrist were included in this study. Group 1 consisted of patients in whom the ulnar styloid base fracture was treated with conventional tension band wiring techniques. Group 2 patients were treated with a supplemental outrigger from the external fixator to the ulna and locked in 60 degrees of forearm supination. Groups 1 and 2 had an average follow-up period of 40 and 36 months, respectively.

RESULTS

Group 2 had significantly better supination than group 1. In terms of functional outcome it was found that there was no significant difference for the Disabilities of the Arm, Shoulder, and Hand and the Gartland and Werley scores between the 2 treatment groups. There was a lower rate of complications and fewer secondary procedures were required in group 2. The incidence of distal ulna resection was 4 of the 35 patients (2 patients in each group).

CONCLUSIONS

Our results indicate that patients in whom the ulnar styloid can be reduced and maintained in supination can be treated effectively with fixed supination outrigger external fixation. This method resulted in a statistically significant improvement in supination and a lower rate of distal radioulnar joint complications, and it required fewer secondary procedures.

Ligamentous stabilization of the distal radioulnar joint

Instability of the distal radioulnar joint results from fracture and/or malunions of the forearm bones, disruption, or laxity of the ligaments of the triangular fibrocartilage. Such instability often-times is not diagnosed acutely and presents as a chronic problem. When these ligaments fail to heal adequately after injury, distal radioulnar joint instability develops into mechanical problems resulting in pain, limited range of motion, and decreased grip strength. In this case, reconstruction of the disrupted distal radioulnar joint ligaments is essential to restore proper function. In this presentation, a technique of ligament reconstruction using palmaris longus, plantaris, or toe extensor tendon graft is outlined with mid-term functional results.

Stability of the distal radioulnar joint contributed by the joint capsule

PURPOSE

The distal radioulnar joint (DRUJ) capsule is assumed to be an important stabilizer of the DRUJ. There are few published data regarding the capsule and its specific contribution to stability of the DRUJ.

METHODS

We analyzed the contribution of the joint capsule to DRUJ stability in a biomechanical study consisting of collection of force/displacement data from 16 adult human cadaveric upper extremities. Each specimen was subjected to anteroposterior translation testing of the radius relative to the ulna in 3 positions of forearm rotation (neutral, 60 degrees pronation, 60 degrees supination) by serial sectioning of the DRUJ capsule. The experimental conditions tested included intact capsule, sectioned dorsal capsule, sectioned volar capsule, and repaired capsule.

RESULTS

Isolated dorsal capsule sectioning resulted in volar instability of the radius to the ulna primarily in the maximum pronated position. Significant dorsal instability of the radius was observed after isolated volar capsule sectioning in the maximum supinated position. The restabilizing effect of capsule shortening was observed near the maximums of forearm rotation. The additional stability owing to capsule shortening surpassed that of the distal radioulnar ligament at these positions.

CONCLUSIONS

We showed the effect of capsular injury on DRUJ joint stability and the restabilizing effect of capsule shortening. The importance of the capsule to DRUJ stability should be considered when planning surgical procedures to restore the unstable DRUJ.

Malunion of the ulnar styloid as a cause of ulnar wrist pain

We present a case of ulnar wrist pain that had been wrongly attributed to non-union of the ulnar styloid. Surgical exploration revealed an ulnar styloid malunion that had caused pain by impinging on the triquetrum and a triangular fibrocartilage complex (TFC) lesion. There was no fracture of the distal radius and no associated carpal instability or disruption of the distal radio-ulnar joint. Treatment by resection of the ulnar styloid and re-attachment of the TFC provided a satisfactory outcome.

Open repair of the ulnar disruption of the triangular fibrocartilage complex with double three-dimensional mattress suturing technique

Open repair technique of the ulnar disruption of the triangular fibrocartilage complex is described. This technique is indicated for a fresh or a relatively fresh (less than 1 year after the initial injury) ulnar foveal detachment tear, horizontal tear, and proximal slit tear of the triangular fibrocartilage complex, all of which are accompanied by severe dorsal, palmar, or multidirectional instability of the distal radioulnar joint. A chronic tear greater than 1 year from initial injury and a fresh triangular fibrocartilage complex tear without distal radioulnar joint instability, such as central slit tear, are excluded from our indications. A dorsal C-shaped skin incision, a longitudinal incision of the radial edge of the extensor carpi ulnaris subsheath and the dorsal distal radioulnar joint capsule, exposes the distal radioulnar joint. A small, 5-mm longitudinal incision at the origin of the radioulnar ligament exposes its fovea detachment and/or the proximal slit tear of the triangular fibrocartilage complex. The disrupted radioulnar ligament is sutured in a pullout fashion to the ulna with a 3-dimensional double mattress technique through 2 bone tunnels that is precisely made at the central portion of the fovea with 1.2-mm K-wire. An additional horizontal mattress suture is used for closure of the small incision made at the radioulnar ligament, then the extensor carpi ulnaris is repaired. This open-repair technique is complex and requires precise technical skills; however, early results have been more rewarding than the conservative treatment.

Relationship between bone mineral density of the distal radius and ulna and fracture characteristics

PURPOSE

This study was designed to elucidate the different decrease patterns of bone mineral density (BMD) in the distal tenth and third of the radius and ulna that influence the incidence of fractures, the fracture type, and redisplacement after closed reduction and casting.

METHODS

The BMD of 1024 healthy women and 86 women treated for distal radius and ulna fracture was measured in the distal tenth and distal third zones of the radius and ulna (termed R10, R3, U10, and U3, respectively) using dual-energy x-ray absorptiometry. The BMD in the fracture group was compared with age-matched BMD in the nonfracture group. The relationship between BMD, type of fracture, and radiographic parameters (radial length, radial inclination, and palmar tilt) determined after closed reduction and at bone union were examined.

RESULTS

The BMD of the distal radius in zones R10 and R3 in the fracture group were significantly lower than those in the nonfracture group among subjects older than 80 years, whereas the BMD in the U10 and U3 in the fracture group were lower than those in the nonfracture group among subjects aged 50 to 59 years. No significant difference in the mean BMD in any of the fracture group subjects was found, irrespective of the fracture pattern. A significant correlation was found between the BMD in the R10 and radial length measured at bone union and between radial length measured at bone union and RL measured after closed reduction. The radial length, radial inclination, and palmar tilt measured at bone union correlated significantly with each other.

CONCLUSIONS

The BMD in the R10 and R3 are potential indicators of a distal radius fracture in women over 80 years old, whereas the U10 and U3 are indicators of an ulnar styloid fracture in women in their fifties. In addition the distal radius (R10) is an important prognostic parameter of possible deformity of the radius after closed reduction and casting.

Kinematic analysis of the distal radioulnar joint after a simulated progressive ulnar-sided wrist injury

A kinematic analysis of a progressive, ulnar-sided wrist injury was performed using a cadaver model to study the static and dynamic stabilizers of the distal radioulnar joint with a 3-dimensional motion tracking system. Anatomically based loads were applied to achieve pronation and supination and then the specimens were evaluated after serial transection of the triangular fibrocartilage, the extensor carpi ulnaris sheath, and the ulnocarpal ligaments. Statistically significant increases in translation of the radius relative to the ulna occurred with sectioning of both the triangular fibrocartilage proper and the extensor carpi ulnaris tendon sheath. No significant change in position of the forearm could be appreciated with subsequent sectioning of the ulnocarpal ligaments. Our observations support the idea that the ulnocarpal ligaments do not need to be surgically reconstructed when there are serious injuries to the triangular fibrocartilage complex.

An anatomic reconstruction of the distal radioulnar ligaments for posttraumatic distal radioulnar joint instability

Fourteen patients with posttraumatic distal radioulnar joint instability were treated with a reconstruction of the distal radioulnar ligaments. The technique is anatomically accurate, is reproducible, and requires less dissection than previously described techniques. Candidates for the procedure had joint instability and an irreparable triangular fibrocartilage complex. Ten patients had bidirectional instability. Two patients had a concurrent corrective osteotomy of the distal radius for a malunion. The procedure restored stability and relieved symptoms in 12 of 14 patients at 1 to 4 years' follow-up evaluation. One patient with a deficient sigmoid notch and one with ulnocarpal ligament injury did not achieve full stability. All patients attained near full pronation and supination. The procedure is an effective treatment for an unstable distal radioulnar joint when its articular surfaces are intact and the other wrist ligaments are functional, and it can be used in combination with a distal radius corrective osteotomy.

Reconstruction of the posttraumatic unstable distal radioulnar joint

Although not a common problem, the posttraumatic unstable distal radioulnar joint can be difficult to treat. This article focuses on the various methods for reconstruction of the unstable distal radioulnar joint. Attention focuses specifically on anatomic reconstruction of distal radioulnar ligaments. The authors' technique is presented in detail.

The triangular fibrocartilage complex: an important component of the pulley for the ulnar wrist extensor

The extensor carpi ulnaris (ECU) tendon is the only wrist motor tendon that broadly connects with the triangular fibrocartilage complex (TFCC) of the wrist. The goal of this study was to determine the biomechanical effect of the TFCC on the function of the ECU. The effect of avulsion of the TFCC on the changes in mechanics of the ulnar wrist extensor tendon was investigated in 8 fresh-frozen cadaver forearms. Excursion of the ECU tendon was continuously recorded over the functional range of wrist extension and ulnar deviation in intact wrists, wrists with ulnar styloid fractures, wrists with TFCC release from the distal ulna, and after excising the distal ECU tendon sheath. The ECU tendon demonstrated a 30% increase in excursion during wrist extension after release of the TFCC from its attachment on the distal ulna. During 60 degrees of wrist extension, excursion of the ECU tendon was 4.8+/-1.9 mm in the intact wrists and 6.3+/-2.0 mm after TFCC release. This change in excursion represented 1.4 mm of bowstringing for the ECU tendon during 60 degrees of wrist extension. Further incision of the distal part of the extensor sheath produced only 6% increase in excursion of the ECU. Results of this study suggest that the TFCC is an important component of the pulley for the ulnar wrist extensor. These findings imply that disturbance of the wrist extensor after TFCC injury may potentially contribute to abnormal loading and force transmission through the ulnar wrist and the TFCC, and support the growing consensus that integrity of the TFCC should be restored in the presence of TFCC injuries.