Effects of wafer resection and hemiresection from the distal ulna on load-sharing at the wrist: a cadaveric study

PURPOSE: Ulnar impaction syndrome is commonly the result of a naturally occurring ulnar-positive condition, distal radius fracture malunion, or collapse of a fractured radial head. The Feldon wafer procedure and the Bowers distal hemiresection procedure are designed to decrease force transmitted through the distal ulna. The purpose of this study was to measure the effects of these procedures on distal ulnar loading with varying degrees of ulnar positivity at the wrist. METHODS: Using a specially designed miniature load cell distal ulnar force was measured in 20 fresh-frozen cadaveric forearms as the wrist was loaded axially to 134 N in neutral forearm rotation; tests were performed in valgus alignment with the elbow flexed to 90 degrees . Ulnar positivity (0 mm, +2 mm, +4 mm, and +6 mm) was created by incremental shortening of the distal radius using a sliding plate. The radial neck was sectioned transversely and the radial head fragment was fixed in its anatomic position using cemented metal prongs connected to a rigid bar; this allowed the radial head to be disconnected and tilted out of the loading pathway to simulate an excised radial head. Loading tests (with and without the radial head in place) were repeated after removal of a 3-mm wafer of bone beneath the triangular fibrocartilage complex, and again after a hemiresection of the distal ulna to the base of the ulnar styloid process. RESULTS: For each ulnar status condition (intact, wafer removal, hemiresection) the mean distal ulnar force generally increased as the wrist became more ulnar positive. Both wafer removal and hemiresection significantly decreased mean distal ulnar forces under all conditions of ulnar variance, with or without the radial head in place. With the radial head in place the mean distal ulnar forces (expressed as a percentage of applied wrist force) for the 0-mm condition were 16.9% (intact), 3.8% (wafer removal), and 3.5% (hemiresection); corresponding values for the +6-mm condition were 61.6% (intact), and 39.8% (wafer removal), 15.1% (hemiresection). With the radial head removed the mean distal ulnar forces for the 0-mm condition were 31.7% (intact), 4.6% (wafer removal), and 4.4% (hemiresection); corresponding values for the +6-mm condition were 96.4% (intact), 71.6%, (wafer removal), and 27.2% (hemiresection). The decrease of distal ulnar force resulting from hemiresection was significantly greater than that for wafer removal for all ulnar-positive conditions; force reductions were not significantly different between the 2 procedures with neutral ulnar variance. CONCLUSIONS: The results of the present study can help to offer a biomechanical basis for choosing between a Feldon wafer procedure and a Bowers hemiresection procedure in patients with ulnocarpal impaction syndrome. Both procedures produced equal decreases of distal ulnar force in the intact forearm. With an ulnar-positive wrist, the condition for which the procedure would be performed commonly, the hemiresection was more effective in decreasing force transmitted through the distal ulna.     

Reconstruction of the interosseous membrane of the forearm with a graft substitute: a cadaveric study

PURPOSE: Longitudinal radioulnar dissociation occurs when traumatic axial loading through the wrist disrupts the interosseous membrane (IOM) of the forearm and fractures the radial head (Essex-Lopresti injury). Proximal migration of the radius results in a wrist with a positive ulnar variance, which leads ultimately to painful ulnar-sided wrist degeneration and wrist pain during grasping activities that involve axial loading or ulnar deviation of the wrist. In theory reconstruction of the IOM with a graft substitute can limit proximal migration of the radius, thereby preserving wrist function. The objective of this study was to measure the abilities of 3 graft tissues to limit proximal radial displacement compared with the native IOM in a radial head-deficient cadaver model. METHODS: Sixteen fresh-frozen cadaveric forearms were loaded axially to 134 N through the potted central 3 metacarpals; the elbow was flexed to 90 degrees with the wrist in neutral rotation. Proximal displacement of the radius relative to the capitellum was measured. With the radial head excised specimens were first tested with the IOM intact. The IOM was then sectioned and central band IOM reconstructions were performed on each specimen using the following tissues: palmaris longus tendon, flexor carpi radialis (FCR) tendon, and a 1-cm- wide bone-patellar tendon-bone (BPTB) onlay allograft. Ten loading cycles were performed with each test configuration. Proximal radial displacement between 13.4 N and 134 N of applied wrist force was analyzed for the 10th loading cycle. The increase in proximal displacement between the first and 10th loading cycles (recorded at 134 N of wrist force) represented permanent elongation of the graft. RESULTS: Mean cross-sectional areas were 5.11 mm2 for the palmaris longus tendon, 15.23 mm2 for the FCR tendon, and 51.59 mm2 for the BPTB allograft. Mean proximal radial displacements were 3.04 mm (intact IOM), 4.37 mm (BPTB), 4.92 mm (FCR tendon), and 6.43 mm (palmaris tendon); all means were significantly different from each other. Mean permanent graft elongations were 0.06 mm (IOM), 0.36 mm (BPTB), 1.25 mm (FCR tendon), and 1.80 mm (palmaris tendon); all means were significantly different from each other with the exception of means for palmaris longus vs FCR and BPTB vs IOM. CONCLUSIONS: No graft reconstruction limited proximal radial displacement as effectively as the native IOM. Of the 3 graft tissues tested the BPTB allograft had the greatest cross-sectional area, allowed the least proximal radial displacement, and displayed the least permanent elongation after 10 cycles of loading. The relatively thin and narrow palmaris longus tendon appears to be the least desirable choice for IOM reconstruction because of its relatively low stiffness and tendency to elongate permanently after cyclic loading. When the radial head is absent rupture of the IOM allows unopposed proximal displacement of the radius relative to the ulna as the wrist is loaded axially. In the present tests all 3 graft tissues used to reconstruct the IOM limited proximal radial displacement. The choice of graft material is an important variable if IOM reconstruction is considered for treatment of an Essex-Lopresti injury.     

Rural perspectives on HIV/AIDS prevention: a comparative study of Thailand and Ghana

The paper compares rural perspectives in Thailand and Ghana on the level of condom acceptance in sexual relations, willingness to test oneself for HIV before and in marriage and sources of information on HIV/AIDS. We also compared the policy approaches to combating HIV/AIDS in both countries. The results indicates that in the villages studied in Thailand, all single men and the majority of the single women were in favour of using condoms in sexual relations. This group also showed a positive attitude to HIV/AIDS test before and in marriage. However, married men in rural Thailand disapproved of the use of condoms with their wives but married women in the sample population were open to the possibility of using condoms. Both married men and women were strongly against HIV/AIDS test in marriage. In contrast to Thailand, most single men in the communities studied in Ghana showed a disapproval to the use of condoms in sexual relations. However, they condoned HIV test before marriage. Married men and women in rural Ghana were against the use of condoms in sexual relations as well as HIV/AIDS test in marriage. In order to mitigate mother-to-child transmission, the Thais applied anti-retroviral drug care for HIV positive pregnant women during pregnancy and after delivery. In Ghana on the other hand, pregnant women were subject to HIV test and counselling. The mode of information acquisition on HIV/AIDS in both countries were through the media, campaigns and village volunteers. Finally, we observed that fighting poverty is a sine qua non for the success of any HIV/AIDS eradication programme.     

Rupture of the renal pelvis of a ureteropelvic junction hydronephrosis after blunt abdominal trauma

In the present case report, we present the unusual occurrence of traumatic rupture of a ureteropelvic junction hydronephrosis, and discuss the potential mechanisms producing such a rupture and the management options.     

Comparison of multi-lineage cells from human adipose tissue and bone marrow

Our laboratory has recently characterized a population of cells from adipose tissue, termed processed lipoaspirate (PLA) cells, which have multi-lineage potential similar to bone-marrow-derived mesenchymal stem cells (MSCs). This study is the first comparison of PLA cells and MSCs isolated from the same patient. No significant differences were observed for yield of adherent stromal cells, growth kinetics, cell senescence, multi-lineage differentiation capacity, and gene transduction efficiency. Adipose tissue is an abundant and easily procured source of PLA cells, which have a potential like MSCs for use in tissue-engineering applications and as gene delivery vehicles.     

High-throughput sequencing analysis of the chromosome 7q32 deletion reveals IRF5 as a potential tumour suppressor in splenic marginal-zone lymphoma

Using high‐resolution genomic microarray analysis, a distinct genomic profile was defined in 114 samples from patients with splenic marginal zone lymphoma (SMZL). Deletion or uniparental disomy of chromosome 7q were detected in 42 of 114 (37%) SMZLs but in only nine of 170 (5%) mature B‐cell lymphomas (P < 0·00001). The presence of unmutated IGHV, genomic complexity, 17p13‐TP53 deletion and 8q‐MYC gain, but not 7q deletion, correlated with shorter overall survival of SMZL patients. Mapping studies narrowed down a commonly deleted region of 2·7 Mb in 7q32.1‐q32.2 spanning a region between the SND1 and COPG2 genes. High‐throughput sequencing analysis of the 7q32‐deleted segment did not identify biallelic deletions/insertions or clear pathogenic gene mutations, but detected six nucleotide changes in IRF5 (n = 2), TMEM209 (n = 2), CALU (n = 1) and ZC3HC1 (n = 1) not found in healthy individuals. Comparative expression analysis found a fourfold down‐regulation of IRF5 gene in lymphomas with 7q32 deletion versus non‐deleted tumours (P = 0·032). Ectopic expression of IRF5 in marginal‐zone lymphoma cells decreased proliferation and increased apoptosis in vitro, and impaired lymphoma development in vivo. These results show that cryptic deletions, insertions and/or point mutations inactivating genes within 7q32 are not common in SMZL, and suggest that IRF5 may be a haploinsufficient tumour suppressor in this lymphoma entity.