MRI criteria for diagnosis and predicting severity of carpal tunnel syndrome.

OBJECTIVE: To study MRI criteria for diagnosing and predicting severity of carpal tunnel syndrome (CTS). METHODS: Sixty-nine wrists in 41 symptomatic CTS patients and 32 wrists in 28 asymptomatic subjects were evaluated by MRI. Circumferential surface area (CSA), flattening ratio, relative median nerve signal intensity, and retinacular bowing were measured. CTS severity was classified as mild, moderate, or severe. Parameters for patients with and without CTS and for the three severity groups were compared. ROC curves were plotted to assess accuracy for CTS diagnosis and severity prediction. RESULTS: Significant differences were found between CTS and control wrists for median nerve CSA, flattening ratio at inlet, relative median nerve signal intensity, and retinacular bowing. ROC curve analysis revealed a sensitivity, specificity, and accuracy of median nerve CSA > 15 mm2 proximal to the tunnel (CSAp) of 85.5, 100, and 90.1%. Using either CSAp or CSAd > 15 mm2 as a diagnostic criterion, MRI could achieve a sensitivity of 100% and specificity of 94% for diagnosis of CTS while overall accuracy was 98%. Significant differences were found among the three severity groups. Sensitivity, specificity, and accuracy of prediction of severe CTS using for CSAp > 19 mm2 were 75.0, 65.9, and 69.6%, respectively. CONCLUSIONS: MRI is highly accurate at diagnosing CTS and moderately accurate at determining CTS severity. We recommend using CSA > 15 mm2 either proximal to or distal to the tunnel as a diagnostic criterion for CTS and CSA > 19 mm2 proximal to the tunnel as a marker for severe CTS.

Top-Ten Tips for Imaging the Triangular Fibrocartilaginous Complex.

The triangular fibrocartilage complex (TFCC) is a crucial structure for both maintaining the stability of the distal radioulnar joint (DRUJ) and acting as a cushion for axial loading of the ulnocarpal joint. Injury to the TFCC can lead to early degeneration of the DRUJ and ulnocarpal joint, with resultant chronic wrist pain and weakness. The TFCC is a moderately complex structure with several attachments to the adjacent bony and cartilaginous structures. Familiarity with the anatomy of the TFCC is a prerequisite for identification of TFCC tears. Several pitfalls can occur while assessing the TFCC on magnetic resonance imaging (MRI) if one is not familiar with the MRI appearances. This article illustrates key tips for diagnosing TFCC tears on MRI.

Cross-sectional area of the median nerve at the wrist: Comparison of sonographic, MRI, and cadaveric measurements.

BACKGROUND: This study compares median nerve cross-sectional area (CSA) measurements at the wrist obtained with ultrasound (US) and magnetic resonance imaging (MRI) using cadaveric measurements as the gold standard. METHODS: Median nerve CSA was measured using US and MRI in 9 cadaveric wrists obtained from 5 subjects at 5 locations: distal forearm, proximal to tunnel inlet, at tunnel inlet, at tunnel outlet, and distal to tunnel outlet and then on identical cadaveric transverse sections obtained with a bandsaw. All US, MRI, and cadaveric measurements were repeated to determine reliability. Median nerves of 10 patients with clinical carpal tunnel syndrome (CTS) were measured with US and MRI using an identical method US. RESULTS: Median nerve CSA MRI measurements correlated better (Pearson correlation: 0.80-0.95, P < .05) with cadaveric measurements than with US measurements (Pearson correlation: 0.61-0.79, P < .05). Median nerve CSA US measurements (8.6-12.5 mm2 , P < .05) were smaller at all levels than MRI (11.3-14.7 mm2 ) or cadaveric (11.0-14.9 mm2 ) measurements while MRI and cadaver measurements were similar at all levels. Median nerve CSA MRI measurements in CTS patients were larger than US measurements at all levels. CONCLUSION: Median nerve CSA measurements by MRI are larger than US measurements and correlated better with cadaveric measurements. Median nerve CSA criteria used for diagnosing CTS on US are not likely to be applicable to MRI.

MR imaging of the traumatic triangular fibrocartilaginous complex tear.

Triangular fibrocartilage complex is a major stabilizer of the distal radioulnar joint (DRUJ). However, triangular fibrocartilage complex (TFCC) tear is difficult to be diagnosed on MRI for its intrinsic small and thin structure with complex anatomy. The purpose of this article is to review the anatomy of TFCC, state of art MRI imaging technique, normal appearance and features of tear on MRI according to the Palmar's classification. Atypical tear and limitations of MRI in diagnosis of TFCC tear are also discussed.

Intrinsic carpal ligaments on MR and multidetector CT arthrography: comparison of axial and axial oblique planes.

PURPOSE: To compare axial and oblique axial planes on MR arthrography (MRA) and multidetector CT arthrography (CTA) to evaluate dorsal and volar parts of scapholunate (SLIL) and lunotriquetral interosseous (LTIL) ligaments. METHODS: Nine cadaveric wrists of five male subjects were studied. The visibility of dorsal and volar parts of the SLIL and LTIL was graded semi-quantitatively (good, intermediate, poor) on MRA and CTA. The presence of a ligament tear was determined on arthrosocopy and sensitivity, specificity and accuracy of tear detection were calculated. RESULTS: Oblique axial imaging was particularly useful for delineating dorsal and volar parts of the LTIL on MRA with overall 'good' visibility increased from 11 % to 78 %. The accuracy of MRA and CTA in revealing SLIL and LTIL tear was higher using the oblique axial plane. The overall accuracy for detecting SLIL tear on CTA improved from 94 % to 100 % and from 89 % to 94 % on MRA; the overall accuracy of detecting LTIL tear on CTA improved from 89 % to 100 % and from 72 % to 89 % on MRA CONCLUSION: Oblique axial imaging during CT and MR arthrography improves detection of tears in the dorsal and volar parts of both SLIL and LTIL. KEY POINTS: • Oblique axial imaging improves SLIL and LTIL visibility and tear detection. • This improvement is greater for the LTIL than for the SLIL ligament. • Overall, CT arthrography performed better than MR arthrography.

Mechanism and epidemiology of paediatric finger injuries at Prince of Wales Hospital in Hong Kong.

OBJECTIVES: To determine the mechanism and epidemiology of paediatric finger injuries in Hong Kong during 2003-2005 and 2010-2012. DESIGN: Comparison of two case series. SETTING: University-affiliated teaching hospital, Hong Kong. PATIENTS: This was a retrospective study of two cohorts of children (age, 0 to 16 years) admitted to Prince of Wales Hospital with finger injuries during two 3-year periods. Comparisons were made between the two groups for age, involved finger(s), mechanism of injury, treatment, and outcome. Telephone interviews were conducted for parents of children who sustained a crushing injury of finger(s) by door. RESULTS: A total of 137 children (group A) were admitted from 1 January 2003 to 31 December 2005, and 109 children (group B) were admitted from 1 January 2010 to 31 December 2012. Overall, the mechanisms and epidemiology of paediatric finger injuries were similar between groups A and B. Most finger injuries occurred in children younger than 5 years (group A, 56%; group B, 76%) and in their home (group A, 67%; group B, 69%). The most common mechanism was crushing injury of finger by door (group A, 33%; group B, 41%) on the hinge side (group A, 63%; group B, 64%). The right hand was most commonly involved. The door was often closed by another child (group A, 37%; group B, 23%) and the injury often occurred in the presence of adults (group A, 60%; group B, 56%). Nailbed injury was the commonest type of injury (group A, 31%; group B, 39%). Fractures occurred in 24% and 23% in groups A and B, respectively. Traumatic finger amputation requiring replantation or revascularisation occurred in 12% and 10% in groups A and B, respectively. CONCLUSIONS: Crushing injury of finger by door is the most common mechanism of injury among younger children and accounts for a large number of hospital admissions. Serious injuries, such as amputations leading to considerable morbidity, can result. Crushing injury of finger by door occurs even in the presence of adults. There has been no significant decrease in the number of crushing injuries of finger by door in the 5 years between the two studies despite easily available and affordable preventive measures. It is the authors' view that measures aimed at promoting public awareness and education, and safety precautions are needed.

Local review of treatment of hand enchondroma (artificial bone substitute versus autologous bone graft) in a tertiary referral centre: 13 years' experience.

OBJECTIVE: To evaluate the treatment outcomes of enchondroma of the hand with artificial bone substitute versus autologous (iliac) bone graft. DESIGN: Historical cohort study. SETTING: Tertiary referral centre, Hong Kong. PATIENTS: A total of 24 patients with hand enchondroma from January 2001 to December 2013 who underwent operation at the Prince of Wales Hospital and Alice Ho Miu Ling Nethersole Hospital in Hong Kong were reviewed. Thorough curettage of the tumour was performed in all patients, followed by either autologous bone graft impaction under general anaesthesia in 13 patients, or artificial bone substitute in 11 patients (10 procedures were performed under local or regional anaesthesia and 1 was done under general anaesthesia). The functional outcomes and bone incorporation were measured by QuickDASH (shortened version of the Disabilities of the Arm, Shoulder and Hand questionnaire) scores and radiological appearance, respectively. The mean follow-up period was 59 months. RESULTS: There were eight men and 16 women, with a mean age of 40 years. Overall, 17 cases involved phalangeal bones and seven involved metacarpal bones. Among both groups of patients, most of the affected digits had good range of motion and function after surgery. One patient in each study group had complications of local soft tissue inflammation. One patient in the artificial bone substitute group was suspected to have recurrence 8 years after operation. Among the autologous bone graft group, four patients had persistent donor site morbidity at the last follow-up. In all patients, radiographs showed satisfactory bone incorporation. CONCLUSIONS: Artificial bone substitute is a safe and effective treatment option for hand enchondroma, with satisfactory functional and radiographic outcomes. Artificial bone substitute offers the additional benefits of enabling the procedure to be done under local anaesthesia on a day-case basis with minimal complications.

Digital ischaemia: a rare but severe complication of jellyfish sting.

We report a case of digital ischaemia in a 31-year-old man who presented with sudden hand numbness, swelling, and cyanosis 4 days after a jellyfish sting. This is a rare complication of jellyfish sting, characterised by a delayed but rapid downhill course. Despite serial monitoring with prompt fasciotomy and repeated debridement, he developed progressive ischaemia in multiple digits with gangrenous change. He subsequently underwent major reconstructive surgery and aggressive rehabilitation. Although jellyfish stings are not uncommon, no severe jellyfish envenomation has been reported in the past in Hong Kong and there has not been any consensus on the management of such injuries. This is the first local case report of jellyfish sting leading to serious hand complications. This case revealed that patients who sustain a jellyfish sting deserve particular attention to facilitate early detection of complications and implementation of therapy.

Arthroscopic resection of wrist ganglion arising from the lunotriquetral joint.

The dorsal wrist ganglion is the most common wrist mass, and previous studies have shown that it arises from the scapholunate interval in the vast majority of cases. Treatment has traditionally been open excision, and more recently arthroscopic resection has been established as an effective and less invasive treatment method. However, application of this technique to ganglia in atypical locations has not been reported, where open excision is the usual practice. This report describes two cases of atypical dorsal wrist ganglia that arose from the lunotriquetral (LT) joint, demonstrated by arthroscopic visualization and wrist arthrogram in one of them. Arthroscopic resection was performed, and the application of this technique to a dorsal wrist ganglion with an atypical origin and location is described.

Wrist Arthroscopy under Portal Site Local Anesthesia (PSLA) without Tourniquet.

UNLABELLED: Purpose wrist arthroscopy is typically performed under general or regional anesthesia with the aid of a tourniquet to maintain a bloodless field. We have been using portal site local anesthesia (PSLA) for wrist arthroscopy without a tourniquet since 1998. The aim of the study was to assess the efficacy, safety, and complications of PSLA and whether this can be recommended for routine wrist arthroscopy. Method We conducted a retrospective study, identifying 111 consecutive cases of wrist arthroscopies performed from January 2007 to December 2009. All cases were performed under PSLA. The effectiveness of PSLA was assessed by analyzing whether the procedure required adjuvant forms of anesthesia. The subjective effectiveness was assessed via phone questionnaires. Results Sixty-eight male and 43 female patients were identified. The average age was 43.2 (range 16-77). The indications included chronic wrist pain of unknown origin (30), posttraumatic arthritis (27), rheumatoid arthritis (5), ganglion (30), triangular fibrocartilage complex (TFCC) injury (14), infectious (1), and carpal instability (4). The average duration of the procedures was 73 minutes (range 20-255 minutes). Therapeutic procedures were performed in all 111 cases in addition to a routine diagnostic assessment. These included arthroscopic debridement (82) synovectomy (6), ganglionectomy (30), TFCC repair (3), TFCC debridement (11), radial styloidectomy (2), wafer procedure (4), thermal shrinkage (2), distal scaphoidectomy (1), and synovial biopsy (4). All procedures could be completed uneventfully. Most patients tolerated the procedure well throughout the operation, and the satisfaction level was high. No complication was encountered. Discussions We concluded that PSLA technique is a feasible mode of anesthesia in selected patients. LEVEL OF EVIDENCE: Level IV.