Morphology of the Radial Attachment of the Radioulnar Ligament and Surrounding Landmarks.

PURPOSE: The triangular fibrocartilage complex (TFCC) is composed of dorsal and palmar radioulnar ligaments (RULs). A common injury pattern of the RUL is the avulsion of the ulnar insertion, which can be treated by arthroscopic or open repair. Although the general method of TFCC reconstruction is a tendon graft with a bone tunnel, detailed information regarding the radial attachment of the RUL is unclear. This study aimed to clarify the morphology of the radial attachments of the palmar radioulnar ligament (PRUL), dorsal radioulnar ligament (DRUL), and short radiolunate ligament (SRL) using three-dimensional imaging. METHODS: A total of 29 upper limbs (16 formalin-fixed and 13 embalmed by Thiel's embalming method) of Japanese cadavers were used. After gross observation, we marked the attachments of the PRUL, DRUL, and SRL using 0.7-mm diameter pins. We created three-dimensional images of the radius, outlining the PRUL, DRUL, and SRL attachments. The software application calculated the centers of the PRUL and DRUL attachments. RESULTS: The PRUL attachment was horizontally shaped. The center of the PRUL was 1.5 mm proximal and 5.8 mm radial to the tip of the palmar pyramid formed by the palmar cortex and the radioulnar and radiocarpal joint surfaces. The DRUL attachment was vertically shaped. The center of the DRUL was 2.0 mm proximal and 1.7 mm radial from the tip of the dorsal pyramid formed by the dorsal cortex and the radioulnar and radiocarpal joint surfaces. The length of the SRL was 9.2 mm. The SRL and PRUL were strongly conjoined. CONCLUSIONS: The anatomical center on the RUL attachment of the radius can be determined from osseous landmarks. CLINICAL RELEVANCE: The findings of this study contribute to the understanding of RUL attachment to the distal radius and may assist surgeons in performing anatomical reconstruction of TFCC.

Load Distribution in Dorsally-Angulated Distal Radius Deformity Using Finite Element Analysis.

PURPOSE: The load axis of the carpals is located on the volar side of the normal distal radius. A volar lunate facet fracture (VLFF) is exposed to volar-shearing stress, which can cause volar displacement of the carpus. A previous biomechanical study reported that the load at the scaphoid fossa was located more dorsally and the pressure at the lunate fossa decreased in a dorsally-angulated model. However, the distal radius load distribution for various volar tilts remains unclear. We speculate that if the volar tilt decreases, the load distribution moves dorsally and decreases the stress on the VLFF. Therefore, we analyzed a dorsally-angulated distal radius model to evaluate changes in the load distribution using finite element analysis. METHODS: A 3-dimensional finite element wrist model was developed using computed tomography images. The ligaments were modeled as tension-only spring elements. We considered the intact wrist model for a volar tilt of 15° and created 5 additional models for volar tilts of 10°, 5°, 0°, -5°, and -10°. RESULTS: As the dorsal angulation increased, the stress distribution moved from volar to dorsal and from the lunate fossa toward the scaphoid fossa. The maximum stress on the volar lunate facet was reduced as volar tilt decreased. The maximum stress was higher on the lunate fossa for volar tilts from 15° to 5°. In contrast, the maximum stress was higher on the scaphoid fossa for volar tilts of ≤0°. CONCLUSIONS: Load transmission moved from volar to dorsal and from the lunate fossa to the scaphoid fossa when the volar tilt decreased. Therefore, a decrease in the volar tilt would reduce the load on the VLFF. CLINICAL RELEVANCE: This study provides surgeons accurate knowledge regarding load distribution of the distal radius for various volar tilts that could be helpful in treating patients with VLFFs.

Radiographic study of the distal ulna in rheumatoid arthritis with extensor digitorum communis ruptures.

OBJECTIVES: Extensor digitorum communis rupture of the wrist often occurs in patients with rheumatoid arthritis. Early operation is desirable for patients with a high risk of rupture; therefore, rheumatologists should diagnose it during daily examinations. This study aimed to clarify radiographic changes in the distal ulna and related factors associated with extensor digitorum communis rupture in patients with rheumatoid arthritis. METHODS: We analysed plain radiographs of 40 patients with rheumatoid arthritis associated with extensor digitorum communis rupture and 62 healthy controls. We investigated the deformation of the distal ulna, Larsen grades, and radiological parameters such as ulnar variance, ulnar bowing angle, dorsal protrusion, and dorsal bowing angle. RESULTS: The ratios of the ulna head deformation, Larsen grades, ulnar variance, dorsal protrusion, and dorsal bowing angle were significantly larger in the ruptured group than in the control group. Multiple logistic regression analysis revealed that dorsal protrusion and Larsen grades were significantly associated with extensor digitorum communis rupture. CONCLUSIONS: Deformity of the distal ulna is evident in patients with an extensor digitorum communis rupture. Ulnar head deformation, high Larsen grades, and large dorsal protrusion are potential risk factors for extensor digitorum communis rupture.

Morphology of the Ulnar Insertion of the Triangular Fibrocartilage Complex and Related Osseous Landmarks.

PURPOSE: In triangular fibrocartilage complex (TFCC) injuries, a foveal tear of the radioulnar ligament often requires surgery. Previous studies have suggested that surgeons should attach the TFCC to the center of the fovea. The TFCC and its insertion points are small structures, and few studies have reported details of the foveal insertion. This study aimed to clarify the morphology of the ulnar insertion of the TFCC and related osseous landmarks with 3-dimensional imaging. METHODS: This study used 26 formalin-fixed cadavers. At the ulna, the TFCC was inserted from the fovea to the middle part of the ulnar styloid. After gross observation of the TFCC, the ulnar insertion was outlined using a 1.0-mm drill. We then created 3-dimensional images of the ulna using computed tomography and marked (with software) an outline of the foveal insertion of the TFCC. We measured the area and the long and short diameters of the TFCC insertion. RESULTS: The area of the TFCC insertion was 34 mm2 and positively correlated with the height of the ulnar styloid and the area of the ulnar head. The TFCC's highest point was 58% of the ulnar styloid height. The center of the TFCC insertion was 1.3 mm ulnar and 0.6 mm dorsal from the lowest point of the ulnar surface. CONCLUSIONS: The center of the TFCC insertion was slightly ulnar of the lowest point of the ulnar surface. This study revealed the center, the area, and the osseous relation of the ulnar insertion of the TFCC. CLINICAL RELEVANCE: When surgeons repair a TFCC foveal tear, they can find the anatomical center of the ulnar insertion efficiently and easily based on its osseous relationship.

Nurse-like cells in rheumatoid arthritis: Formation of survival niches cooperating between the cell types.

Nurse-like cells (NLCs) established from bone marrow and synovial tissue of rheumatoid arthritis (RA) patients were found to promote maturation and differentiation of B lineage cells as well as T cells. In co-culture of RA-NLCs and B cells, tight physical interactions (pseudoemperipolesis) developed, which resulted in activation of both cell types. RA-NLCs also supported myeloid cell maturation, promoting their differentiation into tartrate-resistant acid phosphatase-positive mononuclear cells, which are precursor cells of osteoclasts. In RA synovial tissue, the characteristic dendritic-shaped cells (the DCs) were electron microscopically found to form direct physical interactions with adjacent plasma cells (PCs) suspecting to be pseudoemperipolesis. The numbers of PCs accumulating in various areas tended to correlate with the numbers of the DCs, which appeared to have RA-NLC functions forming survival niches for PCs. Immunohistochemical staining analysis indicated that CD14+ cells including the DCs formed survival niches for CD138+ PCs by RA-NLC functions. Quantitative dual immunofluorescence staining studies of these areas indicated that the majority of CD14+ cells were of myeloid lineage. These survival niches promoted by RA-NLCs appear to play important roles in supporting immunological functions in RA bone marrow and synovial tissues.

Volar locking plates not touching the flexor pollicis longus tendon appear as prominences on radiographs: a cadaver study.

BACKGROUND: Plate protrusion is a risk factor for flexor pollicis longus (FPL) rupture following volar locking plate (VLP) surgery. However, plate prominence on follow-up radiographs is common. We hypothesised that a VLP that does not touch the FPL tendon can appear as a plate prominence projected over the volar ridge on lateral radiographs. MATERIALS AND METHODS: We studied six current designs of widely used plates in formalin-fixed cadavers. Each plate was placed in six cadavers. We analysed 36 different plate-cadaver combinations. The main aim of plate fixation was to position the plate in the most distal position without FPL tendon contact. Radiographs were obtained using fluoroscopy. We evaluated plate prominence from the volar ridge according to the Soong grading system. RESULTS: Soong grades 0 (plate did not extend beyond volar ridge), 1 (plate protruded beyond volar ridge) and 2 (plate directly on or located beyond the volar ridge) were observed in 23 (63.9%), 9 (25.0%) and 4 (11.1%) cadavers, respectively. VariAx, DVR and VALCP showed grade 1 prominence, whereas Acu-Loc2, HYBRIX and MODE showed grade 2 prominence. CONCLUSIONS: Implant protrusion was observed in 36% of plate-cadaver combinations, even if the plate did not touch the FPL. Estimating the risk of FPL rupture using lateral radiographs alone is likely insufficient. Our findings can be applied to accurately identify the presence of implant prominence following VLP surgery.

Flexor tendon transfer for focal dystonia with involuntary flexion of the ring finger.

We report a case of task-specific dystonia characterized by involuntary flexion of the ring finger. After resecting the flexor of the ring finger, the flexor digitorum profundus of the middle finger was transferred to the resected site.

Three-dimensional imaging of the distal radius with reference to volar locking plate surgery.

BACKGROUND: The watershed line is widely accepted as the distal limit of the volar locking plate (VLP); however, the VLP placement could vary depending on the plate contour and morphology of the distal radius. The aim of this study was to investigate the morphology of the distal radius and VLP fitting using 3D images. HYPOTHESIS: We hypothesized that attachment of the VLP would affect the contour of the volar prominence of the distal radius. PATIENTS AND METHODS: Variable-angle LCP two-column volar distal radius Plate 2.4 and 16 formalin-fixed cadavers were studied. The plate and forearm were scanned using a computed tomography scanner. The plate was fixed to the radial shaft in the most distal position without flexor pollicis longus tendon contact. Postero-antero and lateral radiographs were obtained using fluoroscopy. Postero-antero radiographs were superimposed on a 3D image of the distal radius. The virtual plate was attached to the distal radius in the computer simulations and the plate was adjusted in the sagittal plane. In the postero-antero radiographs, the distance between the plate and distal end of the radius (DPR) was measured. In the sagittal plane, the height of the volar lunate facet (VLF) and the plate-to-bone distance of each locking screw hole was measured. The volar cortical angle (VCA) was measured as the angle formed by a line drawn along the volar surface and a line drawn on the radial shaft on the sagittal plane at each locking screw plane. RESULTS: A significant correlation was observed between the height of the VLF and the DPR and between the height of the VLF and the VCA. The plate-to-bone distance at the ulnar screw hole was significantly smaller than that of the other screw holes. DISCUSSION: Our study revealed that the higher the VLF, the more proximal is the VLP. The plate fits on the bone surface at the ulnar side, whereas the radial side has more space between the plate and bone. LEVEL OF EVIDENCE: III, diagnostic Level.

Fractures of the proximal segments of the pediatric distal radial metaphysis exhibit less angular stability than fractures of the distal segments.

The distal part of the forearm is divided into the physis, metaphysis, diaphyseal metaphyseal junction (DMJ) and diaphysis. The treatment of radial DMJ fractures is challenging because this region has diaphyseal characteristics. We speculated that the stability of metaphyseal fractures could vary depending on their proximity to the DMJ or physis. Our study aimed to investigate the stability of pediatric distal radius fractures in the physis, metaphysis and DMJ. Ninety-five patients were classified into three groups: group D, fracture line located within 1/2 of the width of the radius (WOR) from the physis; group M, fracture line located between 1/2 and 1 WOR from the physis; and group P, fracture line located between 1 and 2 WOR from the physis. We measured sagittal angulation and coronal angulation. A correction loss of less than 9° was defined as a 'stable reduction' outcome and one greater than 10° as a 'loss of reduction' outcome. The correction losses for sagittal angulation were significantly greater in groups M and P than in group D. The correction losses for coronal angulation were significantly greater in group P than in groups D and M. The incidence of 'loss of reduction' outcomes was significantly higher in groups M and P than in group D. The proximal segments of distal radial metaphyseal and DMJ fractures showed less angular stability than distal segments.

Supraretinacular endoscopic carpal tunnel release: A safe alternative method for treatment of carpal tunnel syndrome.

PURPOSE: Supraretinacular endoscopic carpal tunnel release (SRECTR) is a technique in which an endoscope is inserted superficial to the flexor retinaculum through a subcutaneous tunnel. The benefits of this method include a clear view for the surgeon and absence of median nerve compression. Surgeons can operate with a familiar view of the flexor retinaculum and median nerve downward, similar to open surgery. This study aimed to investigate the learning curve for SRECTR, an alternate method for carpal tunnel release, and evaluate its complications and the functional outcomes using a disposable commercial kit. METHODS: We examined the open conversion rates and complications associated with SRECTR in 200 consecutive patients performed by two surgeons. We compared the operative time operated by a single surgeon. We evaluated outcomes in 191 patients according to Kelly's grading system. Patients' mean follow-up period was 12.7 months. RESULTS: Nine patients required conversion to open surgery. There were no injuries to the nerves and tendons and no hematoma or incomplete dissection of the flexor retinaculum. The operative times varied between 11 and 34 minutes. We obtained the following results based on Kelly's grading of outcomes: excellent in 116, good in 59, fair in 13, and poor in 3 patients. CONCLUSIONS: We found no patients with neurapraxia, major nerve injury, flexor tendon injury, superficial palmar arch injury, and hematoma. Although there was a learning curve associated with SRECTR, we performed 200 consecutive cases without neurovascular complications. This method may be a safe alternative to minimally invasive carpal tunnel surgery.

Ulnar facet locking screw locations of volar locking plates placed without flexor pollicis longus tendon contact: A cadaver study.

BACKGROUND: The volar locking plate (VLP) system provides stable fixation and is widely used for distal radius fractures. Studies have shown that irritation of the implant prominence is a risk factor for flexor tendon rupture, especially of the flexor pollicis longus (FPL). Contact between VLPs and flexor tendons should be avoided. We aimed to investigate the ulnar facet locking screw locations of various VLPs placed without FPL tendon contact in cadaver wrists. HYPOTHESIS: We hypothesized that ulnar facet locking screws would be in the vicinity of the subchondral bone when the plate is placed in the most distal position without FPL tendon contact. MATERIALS AND METHODS: The study assessed two variable-angles and four fixed locking plates. We placed each plate in six different cadavers, resulting in 36 different plate-cadaver combinations. Plates were placed in the most distal position without FPL tendon contact. We drilled the most ulnar hole (hole A) and the second ulnar hole (hole B) of the distal row. All drilling procedures were performed using a specific jig for each fixed locking plate. For variable-angle locking plates, we drilled with a fixed jig for each plate. We obtained lateral radiographs when the drill penetrated the dorsal cortex and measured the distance between the drill and the articular surface. RESULTS: With regard to hole A, the mean distances between the drill and the center of the articular surface were 2.6-5.2mm for the four fixed locking plates and 4.9-5.6mm for the two variable-angle locking plates. With regard to hole B, the mean distances between the drill and the center of the articular surface were 3.8-5.9mm for the four fixed locking plates and 5.5-5.9mm for the two variable-angle locking plates. DISCUSSION: When clinicians place a VLP without FPL tendon contact, the distance between the ulnar facet screws and the center of the articular surface is over 3mm in most cases. Surgeons should select variable-angle drilling for strong articular support when using variable-angle locking plates. LEVEL OF EVIDENCE: III, diagnostic Level.

Validity of the distance between the anterior humeral line and capitellum as a quantitative measure of supracondylar humeral fracture in children.

INTRODUCTION: The anterior humeral line (AHL) is a radiographic marker used to quantify anterior-posterior displacement in supracondylar humeral fractures on lateral radiographs. As both the anterior border of the capitellum and the undeveloped ossific nucleus are clearly recognisable on lateral radiographs, we analysed the distance between the AHL and capitellum (AC distance). We hypothesised that the AC distance would provide a highly reproducible and useful index of correction losses in supracondylar humeral fractures. MATERIALS AND METHODS: Forty-two patients (mean age: 6.5 years) who had suffered supracondylar humeral fractures were enrolled in this study. The fractures were corrected by cross pinning in 28 patients and by lateral or lateral and posterior pinning in 14 patients. The AC distance, Baumann angle, and tilting angle were measured in radiographs of the supracondylar humeral fractures obtained immediately after surgery and after bone union. Correction losses were calculated and defined as changes in the AC distance, tilting angle, and Baumann angle. We investigated inter-observer and intra-observer variability in all three radiological parameters and also compared these parameters between children who underwent lateral pin fixation and those who underwent crossed pin fixation. RESULTS: An analysis of intra-observer variability yielded values of 0.93, 0.73, and 0.92 for the AC distance, tilting angle, and Baumann angle, respectively. An analysis of inter-observer variability yielded corresponding values of 0.84, 0.46, and 0.79, respectively. Notably, the change in AC distance was significantly smaller in the cross pinning group than in the lateral pinning group. DISCUSSION: Compared with the Baumann angle and tilting angle, the AC distance was identified as the most reliable method for measuring radiographs. Moreover, smaller correction losses were observed with cross pinning than with lateral pinning. Therefore, the AC distance is a useful and accurate quantitative parameter when analysing supracondylar fractures in children using sagittal plane images.

Incidence of tendon rupture following volar plate fixation of distal radius fractures: A survey of 2787 cases.

This study assessed the comprehensive incidence of tendon rupture following volar locking plate (VLP) surgery for a large number of patients with distal radius fractures (DRFs) at multiple facilities in one prefecture, Japan. During the 4-year period, 2787 patients with DRFs underwent fixation using VLP. The overall incidence rates of rupture of the FPL, the extensor pollicis longus, the flexor digitorum profundus of the index finger, and the extensor digitorum communis were 0.35% (10 patients), 0.29% (8 patients), 0.04% (1 patient), and 0.04% (1 patient), respectively.

Superficial Ulnar Artery Crossing Over the Palmaris Longus Tendon at the Wrist in a Cadaver: A Case Report.

Superficial ulnar artery (SUA) is defined as arterial variation of an ulnar artery of high origin that lies superficially in the forearm. Because an SUA may be mistaken for a superficial vein, there is a risk of arterial damage. During routine dissection of the cadaver, we incidentally detected a case of unilateral SUA in the left arm. SUA arose from the axillary artery and descended superficial to the axillary artery and median nerve. At the wrist, the SUA crossed over palmaris longus (PL) tendon from the radial side to the ulnar side. In this cadaver, the PL tendon was located on the ulnar side and was thicker than the flexor carpi radialis tendon. Clinicians should check for the presence of SUA before any technical procedure, because lack of awareness of its presence can have serious consequences.

Conservative treatment of distal ulna metaphyseal fractures associated with distal radius fractures in elderly people.

INTRODUCTION: Although volar locking plates (VLPs) have been exclusively used for unstable distal radius fractures (DRFs), the optimal management of distal ulna fractures (DUFs) remains controversial. Internal fixation using a plate for DUFs might be challenging because of the presence of osteoporotic bone and fragile bone fragments in elderly patients. HYPOTHESIS: We hypothesized that a strategy including VLP fixation for DRFs and non-intervention for DUFs with early wrist mobilization would provide encouraging results in elderly patients. MATERIALS AND METHODS: Eighteen patients (17 women and one man, mean age 74.7 years) were included in the study. According to the Biyani classification, there were seven patients with type-1, three with type-2, five with type-3, and three with type-4 DUFs. Radiological results were analyzed in 18 patients and the clinical results could be evaluated in 10 patients who attended the necessary follow-up meetings. Ulnar angular deformity (UAD) and ulnar shortening amount (USA) were measured using anteroposterior radiographs. USA was defined as the difference in ulnar variance between just after surgery and at the final visit. Clinical results were assessed using the modified Gartland and Werley score, disability arm shoulder hand (DASH) score, range of motion, grip strength, pain, and distal radioulnar joint (DRUJ) instability. RESULTS: All ulna metaphyseal fractures united. The mean UAD just after surgery was 5.9° (range, 0-22). At the final visit, the mean UAD was 6.4° (range, 0-17). The mean USA was 0.35mm, and only one patient showed ulnar shortening of >2mm. The results were "excellent" in nine patients and "good" in one, according to the modified Gartland and Werley score. The mean DASH score was 4.2. Mean flexion and extension angles were 58° and 71°. One patient complained of ulnar-sided pain during exertion and no patients complained of DRUJ instability. DISCUSSION: All DUFs achieved good radiological results, including comminuted fractures. Functional outcomes were promising, including wide wrist ROM and no DRUJ instability. An approach including VLP fixation for DRFs and non-intervention for DUFs is a good option for elderly patients. LEVEL OF EVIDENCE: IV retrospective study.

Interleukin-6 upregulates expression of ADAMTS-4 in fibroblast-like synoviocytes from patients with rheumatoid arthritis.

AIM: A disintegrin-like and metalloproteinase with thrombospondin type 1 motif (ADAMTS)-4 and ADAMTS-5 play crucial roles in the cleavage of aggrecan. Several recent studies have demonstrated the effect of cytokines such as interleukin (IL)-1ß, tumor necrosis factor-α and transforming growth factor-ß on the expression of ADAMTS-4 and ADAMTS-5 in fibroblast-like synoviocytes (FLS). However, the effect of IL-6 remains unclear. The aim of this study is to investigate the expression of ADAMTS-4 and ADAMTS-5 in FLS of rheumatoid arthritis (RA) patients after IL-6 stimulation. METHOD: Immunohistochemical staining was performed to examine the expression and localization of ADAMTS-4 and ADAMTS-5 in RA synovium. FLS isolated from RA patients were stimulated by IL-6 and soluble IL-6 receptor (sIL-6R) in the presence or absence of anti-IL-6R antibody, and the expression levels of ADAMTS-4 and ADAMTS-5 messenger RNA (mRNA) were assessed using real-time polymerase chain reaction. Furthermore, the IL-6 signaling pathway for regulation of ADAMTS-4 and ADAMTS-5 was also examined. RESULTS: Staining for ADAMTS-4 and ADAMTS-5 was mainly observed in the sublining layer of synovial membrane and pannus. The expression of ADAMTS-4 mRNA was increased by IL-6/sIL-6R, whereas that of ADAMTS-5 was decreased. Anti-IL-6R antibody suppressed the effect of IL-6/sIL-6R. Mitogen-activated protein kinase (MAPK)/extracellular signal-related kinase (ERK) kinase (MEK)1/2 inhibitor U0126 inhibited the effect of IL-6/sIL-6R on ADAMTS-4 mRNA expression in FLS. Signal transducer and activator of transcription 3 (STAT3) inhibitor parthenolide inhibited the effect of IL-6/sIL-6R on ADAMTS-4, and downregulated ADAMTS-5 expression. CONCLUSION: These results suggest IL-6 may participate in cartilage destruction in RA as an inducer of ADAMTS-4 expression from FLS.

Quantitative measurement of serum hyaluronic acid molecular weight in rheumatoid arthritis patients and the role of hyaluronidase.

AIM: Hyaluronic acid (HA) is a glycosaminoglycan and is essential for protecting the cartilage surface by its physical property. It is known that serum HA concentration in rheumatoid arthritis (RA) patients is higher than in healthy volunteer. However, molecular weight (MW) of serum HA in RA patients is not clear, since it needs a large sample volume to assay serum HA MW. The aim of this study is to establish the method for measuring serum HA MW in small sample sizes and to assess the association between serum HA MW and hyaluronidase (HAase) activity. METHODS: MW of serum HA in RA patients was measured using high-performance liquid chromatography and HA-binding protein. Additionally, the correlation between serum HA and HAase activity was examined using zymographic measurements. RESULTS: Serum HA MW peaked at 1-2 × 10(5) Da in all cases. However, in certain cases two peaks were observed, one each at low (1-2 × 10(5) Da) and high (8-14 × 10(5) Da) MW. HAase activity was lower in cases exhibiting this two-peaked serum HA MW pattern than in those cases with only a single peak. CONCLUSION: The novel method developed for this study permits accurate measurement of serum HA MW. The correlation observed between serum HA MW and HAase activity suggests that serum HA MW may reflect the condition of subjects' joints.