Mycobacterium abscessus is a rapidly growing Mycobacterium causing a wide spectrum of clinical syndromes. It now is recognized as a pulmonary pathogen to which cystic fibrosis patients have a particular susceptibility. The M. abscessus rough (R) variant, devoid of cell-surface glycopeptidolipids (GPLs), causes more severe clinical disease than the smooth (S) variant, but the underlying mechanisms of R-variant virulence remain obscure. Exploiting the optical transparency of zebrafish embryos, we observed that the increased virulence of the M. abscessus R variant compared with the S variant correlated with the loss of GPL production. The virulence of the R variant involved the massive production of serpentine cords, absent during S-variant infection, and the cords initiated abscess formation leading to rapid larval death. Cording occurred within the vasculature and was highly pronounced in the central nervous system (CNS). It appears that M. abscessus is transported to the CNS within macrophages. The release of M. abscessus from apoptotic macrophages initiated the formation of cords that grew too large to be phagocytized by macrophages or neutrophils. This study is a description of the crucial role of cording in the in vivo physiopathology of M. abscessus infection and emphasizes cording as a mechanism of immune evasion.

https://www.pnas.org/content/pnas/111/10/E943.full.pdf

Mycobacterium abscessus cording prevents phagocytosis and promotes abscess formation

外反母趾の Biomechanical analysis-靴のヒール高との関連

Surgical Pathology of the Nervous System and Its Coverings

http://www.andreaatzei.it/wp-content/uploads/2011/11/HC-def.pdf

Foveal TFCC Tear Classification and Treatment

Advances in radiocarpal and distal radioulnar joint (DRUJ) diagnostic arthroscopy permits a treatment-oriented classification of triangular fibrocartilage complex (TFCC) peripheral tears: 1) repairable distal tears; 2) repairable complete tears; 3) repairable proximal tears; 4) non-repairable tears; and 5) tears associated with DRUJ arthritis. Class 1 tears should be sutured; Class 2 and 3 are associated with DRUJ instability and require TFCC reattachment to the fovea; Class 4 tears need reconstruction using a tendon graft and Class 5 tears require an arthroplasty. Arthroscopic assisted TFCC foveal reattachment is possible through the direct foveal portal, a dedicated DRUJ working portal. Arthroscopic TFCC reconstruction using a tendon graft showed promising results.

/pdf/new-trends-in-arthroscopic-management-of-type-1-b-tfcc-zq79184muf.pdf

New trends in arthroscopic management of type 1-B TFCC injuries with DRUJ instability.

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.

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

Purpose Common causes of dorsal intercalated segment instability (DISI) include scapholunate dissociations and scaphoid fracture nonunions. Although less common than these, scaphotrapezium-trapezoidal (STT) osteoarthritis (OA) may also be associated with the development of a DISI deformity. The clinical implications of this form of carpal instability in cases of STT arthritis are still unknown. To study the radiographic progression and incidence of this entity, we reviewed our patients and report on 24 wrists with DISI in the presence of STT arthritis. Methods A retrospective chart and radiographic review was performed on all patients seen between 1994 and 2004, with the diagnosis of STT arthritis to identify a subgroup of patients with DISI deformity on the presenting radiographs. Patients' clinical and surgical courses were noted. Postoperative radiographic changes were recorded, as were clinical outcomes. Results Sixteen patients with 24 wrists having STT arthritis and DISI deformity on presenting radiographs were identified. The median STT arthritis grade was 3.0 based on a modified Eaton and Glickel grading system. The median radiolunate angle was −21° of dorsal tilt. All patients had normal scapholunate angles. Abnormal scaphoid extension was seen in 19 of 24 wrists as measured by the radioscaphoid angle. Concomitant carpometacarpal arthritis was seen in 67% (n = 16) of the wrists, and midcarpal arthritis was identified in 50% (n = 8) of patients. Fifteen wrists required surgery for the symptoms and were followed up for a mean of 29 months after surgery. In the surgical group the radiolunate angles increased by mean of 6° after surgery. Four of the 15 wrists required revisional surgery for persistent pain. Conclusions Patients with STT arthritis may present with carpal instability that is not related to radiographic scapholunate instability. This instability is characterized by a normal scapholunate angle with an extension stance of the scaphoid and lunate. Midcarpal arthritis may be present. Surgical intervention for patients with STT arthritis and DISI deformity may lead to radiographic progression of midcarpal instability.

The Clinical Implications of Scaphotrapezium-Trapezoidal Arthritis With Associated Carpal Instability

Deep defects of the hand and fingers with an unhealthy bed exposing denuded tendon, bone, joint, or neurovascular structures require flap coverage. However, the location and size of the defects often preclude the use of local flap coverage. Free-flap coverage is often not desirable either, because the recipient vessels may be unhealthy from surrounding infection or trauma. In such situations, a regional pedicled flap is preferable. A solution to this is the heterodigital arterialized flap. This flap is supplied by the digital artery and a dorsal vein of the finger for venous drainage. Unlike the neurovascular island flap, the digital nerve is left in situ in the donor finger, thus avoiding many of the neurologic complications associated with the Littler flap. The digital artery island flap is centered on the midlateral line of the donor finger. It extends from the middorsal line to the midpalmar line. The maximal length of the flap is from the base of the finger to the distal interphalangeal joint. By preserving the pulp and the digital nerve, a sensate pulp on the donor finger remains that reduces donor-finger morbidity and also preserves fingertip cosmesis. Twenty-nine flaps were performed in 29 patients and the outcomes in the donor finger and the reconstructed finger were reviewed. The flap survival was 100 percent. There were no cases of flap ischemia or flap congestion. Good venous drainage of the flap through the additional dorsal vein was helpful in preventing the occurrence of early postoperative venous congestion, which is common in island flaps of the fingers, which depend on only the venae comitantes for drainage. Donor-finger morbidity, measured in terms of range of motion and two-point discrimination in the pulp, was minimal. Ninety-seven percent of the donor fingers achieved excellent or good total active motion according to the criteria of Strickland and Glogovac. Pulp sensation in the donor fingers was normal in 28 of the 29 donor fingers. No cold intolerance of the donor finger or the adjacent finger is reported in this series.

Heterodigital arterialized flaps for large finger wounds: results and indications.

Purpose The braided polyblend (FiberWire) suture is recognized for its superiority in tensile strength in flexor tendon repair. The purpose of this study was to compare the biomechanical performance of 3 loop-suture materials used in a locking 6-strand flexor tendon repair configuration: braided polyblend (FiberLoop 4-0), cable nylon (Supramid Extra II 4-0), and braided polyester (Tendo-Loop 4-0). We hypothesized that, using this technique, the braided polyblend suture would give superior tensile strength compared with the other 2 suture materials. Methods We divided 30 fresh porcine flexor tendons transversely and repaired each with 1 of the 3 suture materials using a modified Lim-Tsai 6-strand suture technique. We loaded the repaired tendons to failure using a materials testing machine and collected data on the mechanism of failure, ultimate tensile strength, gap strength, and stiffness. Results Failure mechanisms for the repaired specimens were as follows: the braided polyblend had 50% suture breakage and 50% suture pullout; the cable nylon had 100% suture breakage; and the braided polyester had 80% suture breakage and 20% suture pullout. Specimens repaired with the braided polyblend suture had the highest mean ultimate tensile strength (97 N; standard deviation, 22) and the highest mean gap force (35 N; standard deviation, 7). Conclusions This study supports the findings of previous studies showing superior strength of the braided polyblend suture. Clinical relevance We were able to achieve up to 124 N in ultimate tensile strength and 48 N of gap force with this suture in porcine tendons. This gives greater confidence in starting immediate controlled passive or active rehabilitation after repair of flexor tendon injuries.

A biomechanical comparison of 3 loop suture materials in a 6-strand flexor tendon repair technique.

Purpose Trapeziectomy for the treatment of trapeziometacarpal (TM) osteoarthritis (OA) disrupts the scaphotrapezium-trapezoidal ligament complex and may be associated with carpal collapse in a subset of patients in the form of nondissociative dorsal intercalated segment instability (DISI). The purpose of this study was to examine the clinical and radiographic outcomes of trapeziectomy, documenting the incidence of postoperative carpal collapse, and to determine whether this outcome is correlated with preoperative radiographic findings. Methods A retrospective chart and radiographic review was performed on 33 wrists having trapeziectomy from January 1999 to January 2006. Three surveys were administered to patients after surgery to assess subjective levels of pain, function, and satisfaction. The Wilcoxon signed-rank test was used to determine significant differences in radiographic angles, and McNemar's chi-square test was used to determine significant differences in the frequency of a DISI finding. Results Stage IV disease was present in 58% of wrists; all wrists were followed up at a mean of 10.5 months after surgery. The mean postoperative change in the radiolunate angle was 4.4° of increased dorsal tilt. Radioscaphoid angles changed after surgery by a mean of 6.3° of increased extension. The frequency of DISI as measured by the radiolunate angle increased significantly, from 27% before surgery to 50% after surgery. Scaphotrapezium-trapezoidal arthritis was observed in 58% of wrists; within this subset, DISI was present in 39% before surgery and 62% after surgery. Those patients with a DISI deformity were significantly less satisfied following surgery than those without this finding. Conclusions Patients having trapeziectomy for treatment of TM OA may be at risk for the development of carpal instability. This instability may manifest through either a DISI posture of the wrist or abnormal extension of the scaphoid in the presence of a normal scapholunate angle. The presence of stage IV TM OA may be correlated with an increased incidence of carpal instability after surgical intervention. These radiographic findings are mirrored by a trend toward increased levels of pain and decreased levels of function and satisfaction in those patients with evidence of DISI. Type of study/level of evidence Therapeutic IV.

Shian Chao Tay

Papers

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

The Clinical Implications of Scaphotrapezium-Trapezoidal Arthritis With Associated Carpal Instability

Heterodigital arterialized flaps for large finger wounds: results and indications.

A biomechanical comparison of 3 loop suture materials in a 6-strand flexor tendon repair technique.

Trapeziectomy and Carpal Collapse