The Function of the Distal Interosseous Membrane and its Relevance to the Stability of the Distal Radioulnar Joint: An Anatomical and Biomechanical Review.

The purpose of this article is to review functional anatomy and biomechanics of the distal interosseous membrane (DIOM) and its relevance to the stability of the distal radioulnar joint. The intact DIOM constrained dorsal dislocation of the radius, but it seldom constrained palmar dislocation. A residual ulnar translation deformity of the radial shaft in distal radius fractures has the potential to cause the distal radioulnar joint instability when the triangular fibrocartilage complex injury is also present, because it may result in detensioning of DIOM. Ulnar shortening with the osteotomy performed proximal to the attachment of the DIOM had a more favorable effect on stability of the DRUJ compared with the effect of distal osteotomy, especially in the presence of the distal oblique bundle (DOB). The longitudinal resistance to ulnar shortening was significantly greater in proximal shortening than in distal shortening.

A comparison of 3-D computed tomography versus 2-D radiography measurements of ulnar variance and ulnolunate distance during forearm rotation.

Positive ulnar variance is associated with ulnar impaction syndrome and ulnar variance is reported to increase with pronation. However, radiographic measurement can be affected markedly by the incident angle of the X-ray beam. We performed three-dimensional (3-D) computed tomography measurements of ulnar variance and ulnolunate distance during forearm rotation and compared these with plain radiographic measurements in 15 healthy wrists. From supination to pronation, ulnar variance increased in all cases on the radiographs; mean ulnar variance increased significantly and mean ulnolunate distance decreased significantly. However on 3-D imaging, ulna variance decreased in 12 cases on moving into pronation and increased in three cases; neither the mean ulnar variance nor mean ulnolunate distance changed significantly. Our results suggest that the forearm position in which ulnar variance increased varies among individuals. This may explain why some patients with ulnar impaction syndrome complain of wrist pain exacerbated by forearm supination. It also suggests that standard radiographic assessments of ulnar variance are unreliable.

Palmar reconstruction of the triangular fibrocartilage complex for instability of the distal radioulnar joint: a biomechanical study.

We developed a new triangular fibrocartilage complex reconstruction technique for distal radioulnar joint instability in which the palmar portion of the triangular fibrocartilage complex was predominantly reconstructed, and evaluated whether such reconstruction can restore stability of the distal radioulnar joint in seven fresh cadaver upper extremities. Distal radioulnar joint instability was induced by cutting all soft-tissue stabilizers around the distal ulna. Using a palmar approach, a palmaris longus tendon graft was sutured to the remnant of the palmar radioulnar and ulnocarpal ligaments. The graft was then passed through a bone tunnel created at the fovea and was sutured. Loads were applied to the radius, and dorsopalmar displacements of the radius relative to the ulna were measured using an electromagnetic tracking device in neutral rotation, 60° supination and 60° pronation. We compared the dorsopalmar displacements before sectioning, before reconstruction and after reconstruction. Dorsopalmar instability produced by sectioning significantly improved in all forearm positions after reconstruction.

Comparison of three dimensional and radiographic measurements in the analysis of distal radius malunion.

To estimate the accuracy of radiographic deformity evaluation for distal radius malunion, we compared the results obtained from radiographic measurements (palmar tilt, radial angle, and ulnar variance) with those from the three-dimensional (3D) method using computer bone models in 20 dorsally tilted malunions. Dorsal tilt deformity, radial tilt deformity, and shortening deformity were calculated using the unaffected side as a reference. The 3D method showed a slightly lower value for dorsal tilt deformity than the radiographic evaluation, but the difference was < 10° in all cases. In patients with dorsal tilt ≥ 40°, notable differences in radial tilt evaluation were observed between the two methods compared with patients with less dorsal tilt. The 3D shortening showed positive correlations with radiographic evaluation, but a discrepancy of ≥ 2 mm was observed in eight cases. Palmar tilt is reliable for surgical planning, but radial angle and ulnar variance may be less accurate than previously thought.

Three-dimensional deformity analysis of malunited distal radius fractures and their influence on wrist and forearm motion.

Little information exists about three-dimensional (3-D) deformity patterns of malunited distal radius fractures including axial deformity. The current study aimed to clarify the 3-D deformity pattern of malunited distal radius fractures and reveal the influence of osseous deformities, including axial rotation deformity, on wrist and forearm motion. The deformity of 20 dorsally tilted malunions were evaluated using 3-D computer models created from CT data, and correlations between deformity components and range of motion were assessed. The 3-D deformity analysis showed that axial malalignment in pronation, which showed a correlation with the degree of radial tilt deformity, was very common. A radial tilt deformity of > 5° was observed in only 45% of cases. Although the range of wrist flexion and extension showed a correlation with dorsal tilt deformity, the range of forearm pronation and supination did not correlate with distal radius deformities.

A hydrocellular foam dressing versus gauze: effects on the healing of rat excisional wounds.

OBJECTIVE: Hydrocellular foam dressings are characterised by their ability to create a moist wound healing environment and absorb high amounts of exudate. In this study, we examined the effect of a hydrocellular foam dressing on the healing of rat excisional wounds. METHOD: One full-thickness wound was made on the back of rats and wounds were treated with hydrocellular foam dressing or gauze dressing. To examine the histology of the wound, haematoxylin and eosin (HE) staining was performed. Gene expression of vascular endothelial growth factor (VEGF), fibroblast growth factor (FGF), hepatocyte growth factor (HGF) and hypoxia inducible factor-1 alpha (HIF-1a) in granulation tissue was examined by real-time reverse transcription polymerase chain reaction (real-time RT-PCR). VEGF protein was measured by ELISA. RESULTS: The hydrocellular foam dressing promoted formation of granulation tissue and significantly promoted wound closure. A scab formed on the surface of granulation tissue in the gauze-treated wounds, which disturbed epithelialisation. In addition, the expression of VEGF and mRNA was higher in the gauze-treated wounds. CONCLUSION: These results supports the hypothesis that gauze encourages scab formation, which impairs epithelialisation and increases VEGF expression. In contrast, hydrocellular foam dressing accelerates epithelialisation and new vessel formation in granulation tissue.

Tumorous calcification causing carpal tunnel syndrome.

PURPOSE: There is little information on solitary tumorous calcification causing carpal tunnel syndrome in the literature. This study describes our experience with surgically treated cases of solitary tumorous calcification causing carpal tunnel syndrome. METHODS: Seven patients with symptomatic carpal tunnel syndrome who had tumorous calcification in the carpal tunnel confirmed by radiographical examinations and had then undergone open incisional carpal tunnel release were reviewed. The precise location and the appearance of the calcified mass were confirmed with the preoperative radiographic examinations and the operative records. The additional histology and the composition analysis of the calcified mass were also reviewed in five removed calcifications. RESULTS: Radiographs of each hand revealed a mass of calcification lying anterior to the capitate bone in the carpal tunnel. Intraoperatively, an oval calcified nodule, measuring 10 x 10 x 10 - 18 mm, was observed overlying the capitate, attached firmly to the palmar radiocarpal extrinsic ligament. A composition with an average of 60 % basic calcium phosphate was revealed by infrared absorption spectrometry. Histological sections showed a calcified deposit surrounded by fibrocartilagenous tissue in three cases. CONCLUSION: These facts suggest that the pathogenesis of tumorous calcification causing carpal tunnel syndrome is comparable with that of calcifying tendinitis of the rotator cuff in which a cell-mediated reactive process plays an important role at the tendon insertion.

A three-dimensional quantitative analysis of carpal deformity in rheumatoid wrists.

We have measured the three-dimensional patterns of carpal deformity in 20 wrists in 20 rheumatoid patients in which the carpal bones were shifted ulnarwards on plain radiography. Three-dimensional bone models of the carpus and radius were created by computerised tomography with the wrist in the neutral position. The location of the centroids and rotational angle of each carpal bone relative to the radius were calculated and compared with those of ten normal wrists. In the radiocarpal joint, the proximal row was flexed and the centroids of all carpal bones translocated in an ulnar, proximal and volar direction with loss of congruity. In the midcarpal joint, the distal row was extended and congruity generally well preserved. These findings may facilitate more positive use of radiocarpal fusion alone for the deformed rheumatoid wrist.

Type I versus type II lunates: Ligament anatomy and presence of arthrosis.

One hundred-seventy embalmed cadaver wrists were dissected. The type of lunate (type I, no medial hamate facet; type II, medial hamate facet), the incidence and location of arthrosis (exposed subchondral bone) in the lunohamate joint, and the anatomic relationship of the volar triquetrocapitate (T-C) and the volar triquetrohamate (T-H) ligaments were identified and measured. The relationship between the T-C and T-H ligaments was classified into 3 types. In type A the T-C ligament was completely separate from the T-H ligament, in type B the T-C ligament overlapped the T-H ligament, and in type C the T-C ligament had an additional ligament from the triquetrum to the proximal pole of the hamate. Eighty-two percent of type I lunates were associated with a type A relationship between the T-C and the T-H ligaments and 96% of type II lunates were associated with a type C relationship between the T-C and the T-H ligaments. Arthrosis at the proximal pole of the hamate was more commonly associated with the type II lunates (49%) and with the type C relationship (57%) of the T-C and T-H ligaments. The incidence of arthrosis in the lunohamate joint was also significantly greater in the type II lunate with a medial facet of 3 mm or more.

Early, wide excision of heterotopic ossification in the medial elbow.

To prevent the occurrence of secondary contracture during maturation of heterotopic ossification of the elbow, early, wide excision of heterotopic ossification was performed on 9 consecutive patients with a stiff elbow caused by the mass. The average duration between initial injury and operation was 7.7 months. The thick, elastic mass on the posterior oblique ligament of the medial collateral ligament, which included mature and immature heterotopic ossification, was resected widely with the posterior oblique ligament, the posteromedial joint capsule, and the surrounding scar tissue. After an average follow-up of 52.0 months, the total arc of motion improved from a preoperative mean of 37.3 degrees to a postoperative mean of 112.8 degrees. No patient complained of instability or pain on movement. Despite recurrence of spotty heterotopic ossification at the medial elbow in 5 cases, at final follow-up, a sufficient range of motion was obtained in all patients.

The scaphotrapezio-trapezoidal joint. Part 1: An anatomic and radiographic study.

To evaluate anatomic variations and distribution of degenerative changes in the scaphotrapezio-trapezoidal (STT) joint, 165 embalmed cadaver wrists were examined. An interfacet ridge on the distal scaphoid was found in 81% of the wrists and the shape of the distal joint surface of the scaphoid was classified into 3 types. Underdevelopment of the capitate-trapezium ligament was found in 15% of the wrists. A new skeletal measurement for the inclination of the joint surface of the trapezium-trapezoid in the STT joint (TT inclination) was investigated anatomically and radiographically. Degenerative changes were found in 39% of the wrists. The most common location of degenerative changes was on its ulnar aspect on the distal scaphoid and on the radial and central aspect of the trapezoid on the TT side. The presence of degenerative changes had a significant correlation with a higher anatomic and/or radiographic TT inclination and/or underdevelopment of the capitate-trapezium ligament.

The scaphotrapezio-trapezoidal joint. Part 2: A kinematic study.

Kinematics of the scaphotrapezio-trapezoidal joint during wrist flexion/extension motion (FEM) and radial/ulnar deviation (RUD) was investigated using a 3-dimensional dynamic motion analysis system. The scaphoid/trapezoid motion was found to be a rotational motion obliquely oriented relative to the sagittal plane of the wrist and described in an ulnoflexion/radial extension motion plane in both FEM and RUD of the wrist. The axis of rotation of the scaphoid/trapezoid motion during both FEM and RUD wrist motions was essentially the same and runs through the radiopalmar aspect of the distal scaphoid and the waist of the capitate. Motion analysis also revealed that the trapezium-trapezoid and trapezoid-capitate joints are essentially immobile. Hence, the scaphotrapezio-trapezoidal motion is considered to be a single degree of freedom that is essentially the same in both FEM and RUD of the wrist.

Scaphoid nonunions: a 3-dimensional analysis of patterns of deformity.

We tested the hypothesis that the fracture location of scaphoid nonunions relates to the fracture displacement, development of dorsal intercalated segment instability (DISI) deformity, and changes in the contact area of the bones in the radiocarpal joint. Eleven patients with scaphoid nonunions were examined with 3-dimensional computed tomography and a new method of proximity mapping. Two different patterns of displacement of scaphoid nonunions were demonstrated, 1 volar and 1 dorsal. All patients with a volar pattern scaphoid nonunion had a DISI deformity. Only a few of the patients with a dorsal pattern scaphoid nonunion, mostly in longstanding nonunions, had a DISI deformity. The fracture line was generally distal to the dorsal apex of the ridge of the scaphoid in the volar-type fractures and proximal in the dorsal displaced fractures. The proximity map of the distal fragment of the scaphoid on the radius in the volar type shifts radial compared with normal; in the distal type it shifts dorsal. Neither of the patterns showed any significant changes of the proximity map in the radiocarpal joint at the proximal scaphoid fragment and the lunate. Whether the fracture line passes distal or proximal to the dorsal apex of the ridge of the scaphoid appears to determine the likelihood of subsequent fracture displacement, DISI deformity, and contact area of the bones in the radiocarpal joint.

The relationship between the site of nonunion of the scaphoid and scaphoid nonunion advanced collapse (SNAC).

We studied retrospectively the radiographs of 33 patients with late symptoms after scaphoid nonunion in an attempt to relate the incidence of scaphoid nonunion advanced collapse (SNAC) to the level of the original fracture. We found differing patterns for nonunion at the proximal, middle and distal thirds. The mean intervals between fracture and complaint were 20.9, 6.7 and 12.6 years and obvious degenerative changes occurred in 85.7%, 40.0% and 33.3%, for the six proximal-, eight middle- and two distal-third nonunions, respectively. Nonunion at the proximal and middle thirds showed the first degenerative changes at the radioscaphoid joint, and this was followed by narrowing of the scaphocapitate and then the lunocapitate joints. In our two nonunions of the distal third degenerative changes were seen only at the lunocapitate joint. Most patients with SNAC and nonunion of the middle or distal third showed dorsal intercalated instability; few patients with nonunion of the proximal third developed this deformity. We discuss the initial management of nonunion of the scaphoid at different levels in the light of our findings, and make recommendations.

Reconstruction of the coronoid for chronic dislocation of the elbow. Use of a graft from the olecranon in two cases.

Persistent dislocation of the elbow after a fracture of the coronoid process is a difficult problem. We have performed an open reduction with reconstruction of the coronoid by an osteocartilaginous graft from the ipsilateral olecranon for two patients. Both achieved a painless, stable joint with a functional range of movement. The joint surface of the graft has a similar curve to that of the coronoid giving good congruency and stability. The technique is simple and the graft is obtained through the same incision.

Attritional rupture of flexor tendons by the head of the ulna associated with a chronic longitudinal radioulnar dissociation.

A 62-year-old woman sustained multiple attritional ruptures of the flexor tendons at the wrist caused by displacement of the head of the ulna. She had had injuries of the wrist and elbow when she was young, which were thought to have caused chronic longitudinal radioulnar dissociation with palmar dislocation of the head of the ulna. Attrition of the flexor tendons by the dislocated ulnar head during pronation and supination was the major mechanism for the ruptures in this case. She was successfully treated with tendon transfer and resection of the ulnar head.

Impaired response of gastric vessels to prostaglandin E2 in rats with persistent obstructive jaundice.

We investigated the response of gastric vessels to prostaglandin (PG) E2 after intra-duodenal release of bile in rats with obstructive jaundice. The animals were divided in four groups according to duration of bile duct obstruction (BDO): control and 1 week (W), 2W, and 3W groups. Prolonged BDO decreased gastric mucosal blood flow (BF) significantly. The BF recovered after the release of BDO in the 1W and 2W groups, but not in the 3W group. BDO decreased PGE2 content in gastric mucosa in the 1W, 2W, and 3W groups. PGE2 decreased vascular perfusion pressure of the isolated stomach in the control and 2W groups, but not in the 3W group. The response of gastric vessels to PGE2 was poor in the 3W group compared with the control and 2W groups. Decreased PGE2 in the gastric mucosa and decreased response of gastric vessels to PGE2 may affect gastric blood flow in obstructive jaundice.

[The mechanism of development of acute gastric ulceration following biliary drainage in obstructive jaundice].

Upper gastrointestinal hemorrhage occurs occasionally in the time of surgery or biliary infection in patients with obstructive jaundice. In the present study, the influence of obstructive jaundice and biliary drainage on the rat gastric mucosa was examined. Serum t-Bil, GOT and Alp increased during obstructive jaundice, but decreased following biliary drainage. Hexose and fucose levels in gastric mucosa decreased during obstructive jaundice; both of them increased in the 1- and 2-week jaundiced groups, however, neither increased in the 3-week jaundiced group following biliary drainage. Prolonged obstructive jaundice demonstrated a marked increase of ulcer index (UI) and decrease of gastric mucosal blood flow (BF) following water immersion and restraint stress. Biliary drainage induced these changes in the 1- and 2-week jaundiced groups, but induced neither of these changes towards recovery in the 3-week jaundice group. Prostaglandin (PG) E2 induced significant decrease in isolated gastric vascular perfusion pressure in the 2-week jaundiced group; it did not, however, have this effect in the 3-week jaundiced group. In conclusion, it was speculated that differences between the 3-week and 2-week jaundiced groups were present in sensitivity to PGE2 in the gastric vascular system, and that different reactions of the gastric microcirculation resulted in different changes in the gastric mucosal state following biliary drainage.