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.

Ultrasound carpal tunnel syndrome: additional criteria for diagnosis.

AIM: To define the usefulness of the cross-sectional area (CSA) of the median nerve distal to the carpal tunnel in addition to other established common parameters in the diagnosis of carpal tunnel syndrome (CTS). MATERIALS AND METHODS: Forty-four wrists from 24 symptomatic CTS patients and 32 wrists from 17 asymptomatic volunteers were evaluated by ultrasound. The CSA of the median nerve was measured at four pre-selected levels, i.e., proximal, inlet, outlet, and distal to the carpal tunnel. The flattening ratio, intraneural vascularity, neural fasciculation, and retinacular palmar bowing were also assessed. RESULTS: Significant differences were found between the CTS and control groups for median nerve CSA proximal and distal (p<0.001) to the tunnel as well as retinacular bowing (p<0.001). Using the receiver operating characteristic (ROC) curve, the sensitivity, specificity, and accuracy of using a cut-off of >14 mm2 of CSA proximal and distal to the tunnel were 75%, 87.5%, 86.8% and 63.6%, 100%, 78.9%, respectively. Using either CSA proximal or distal to the tunnel or bowing retinaculum at the outlet >1 mm yielded a sensitivity, specificity, and accuracy of 100%, 84.3% and 93.4%, respectively. CONCLUSION: The median nerve CSA proximal and distal to the carpal tunnel and bowing of the retinaculum at the outlet are helpful in diagnosis of CTS.

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.

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.

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.

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.

Intrinsic ligament and triangular fibrocartilage complex tears of the wrist: comparison of MDCT arthrography, conventional 3-T MRI, and MR arthrography.

PURPOSE: This study compares the diagnostic performance of multidetector CT arthrography (CTA), conventional 3-T MR and MR arthrography (MRA) in detecting intrinsic ligament and triangular fibrocartilage complex (TFCC) tears of the wrist. MATERIALS AND METHODS: Ten cadaveric wrists of five male subjects with an average age 49.6years (range 26-59years) were evaluated using CTA, conventional 3-T MR and MRA. We assessed the presence of scapholunate ligament (SLL), lunotriquetral ligament (LTL), and TFCC tears using a combination of conventional arthrography and arthroscopy as a gold standard. All images were evaluated in consensus by two musculoskeletal radiologists with sensitivity, specificity, and accuracy being calculated. RESULTS: Sensitivities/specificity/accuracy of CTA, conventional MRI, and MRA were 100%/100%/100%, 66%/86%/80%, 100%/86%/90% for the detection of SLL tear, 100%/80%/90%, 60%/80%/70%, 100%/80%/90% for the detection of LTL tear, and 100%/100%/100%, 100%/86%/90%, 100%/100%/100% for the detection of TFCC tear. Overall CTA had the highest sensitivity, specificity, and accuracy among the three investigations while MRA performed better than conventional MR. CTA also had the highest sensitivity, specificity, and accuracy for identifying which component of the SLL and LTL was torn. Membranous tears of both SLL and LTL were better visualized than dorsal or volar tears on all three imaging modalities. CONCLUSION: Both CT and MR arthrography have a very high degree of accuracy for diagnosing tears of the SLL, LTL, and TFCC with both being more accurate than conventional MR imaging.

Is dynamic contrast-enhanced MRI useful for assessing proximal fragment vascularity in scaphoid fracture delayed and non-union?

OBJECTIVE: To assess dynamic contrast-enhanced magnetic resonance imaging (DCE MRI) as a measure of vascularity in scaphoid delayed-union or non-union. MATERIALS AND METHODS: Thirty-five patients (34 male, one female; mean age, 27.4 ± 9.4 years; range, 16-51 years) with scaphoid delayed-union and non-union who underwent DCE MRI of the scaphoid between September 2002 and October 2012 were retrospectively reviewed. Proximal fragment vascularity was classified as good, fair, or poor on unenhanced MRI, contrast-enhanced MRI, and DCE MRI. For DCE MRI, enhancement slope, Eslope comparison of proximal and distal fragments was used to classify the proximal fragment as good, fair, or poor vascularity. Proximal fragment vascularity was similarly graded at surgery in all patients. Paired t test and McNemar test were used for data comparison. Kappa value was used to assess level of agreement between MRI findings and surgical findings. RESULTS: Twenty-five (71 %) of 35 patients had good vascularity, four (11 %) had fair vascularity, and six (17 %) had poor vascularity of the proximal scaphoid fragment at surgery. DCE MRI parameters had the highest correlation with surgical findings (kappa = 0.57). Proximal scaphoid fragments with surgical poor vascularity had a significantly lower Emax and Eslope than those with good vascularity (p = 0.0043 and 0.027). The sensitivity, specificity, positive and negative predictive value and accuracy of DCE MRI in predicting impaired vascularity was 67, 86, 67, 86, and 80 %, respectively, which was better than that seen with unenhanced and post-contrast MRI. Flattened time intensity curves in both proximal and distal fragments were a feature of protracted non-union with a mean time interval of 101.6 ± 95.5 months between injury and MRI. CONCLUSIONS: DCE MRI has a higher diagnostic accuracy than either non-enhanced MRI or contrast enhanced MRI for assessing proximal fragment vascularity in scaphoid delayed-union and non-union. For proper interpretation of contrast-enhanced studies in scaphoid vascularity, one needs to incorporate the time frame between injury and MRI.

Factors affecting mortality in Hong Kong patients with upper limb necrotising fasciitis.

OBJECTIVE: To identify predictive factors for mortality of patients with upper limb necrotising fasciitis. DESIGN: Retrospective study. SETTING: Six hospitals in Hong Kong. PATIENTS: Clinical records of 29 patients treated in the hospitals were traced and analysed. MAIN OUTCOME MEASURES: Possible predictive factors for mortality as evaluated by application of Fisher's test. RESULTS: Overall mortality was 28%. Digital infections conferred a lower mortality, but progressive necrosis necessitated amputation. Vibrio vulnificus was the commonest organism identified in association with marine injury and in patients with cirrhosis. Prognostic indicators with decreasing significance include deranged renal and liver function, thrombocytopaenia, proximal involvement (elbow or above) initially, and presence of hypotension upon admission. CONCLUSION: With a P value of less than 0.05, deranged renal and liver function, thrombocytopaenia, initial proximal involvement, and hypotension on admission were predictors of mortality in necrotising fasciitis affecting the upper limbs. The ALERTS (Abnormal Liver function, Extent of infection, Renal impairment, Thrombocytopenia, and Shock) score with a cutoff of 3 appeared to predict mortality.

Surgical excision for challenging upper limb nerve sheath tumours: a single centre retrospective review of treatment results.

OBJECTIVE: To review the accuracy of different investigation modalities for upper limb nerve sheath tumours and the resulting surgical outcomes, and propose a standard algorithm to deal with such tumours to minimise complications. DESIGN: Retrospective review. SETTING: Regional hospital, Hong Kong. PATIENTS: All patients with upper limb nerve sheath tumours being excised in our hospital from 1999 to 2008. MAIN OUTCOME MEASURES: The accuracy rate of different investigations, as well as corresponding neurological deficits after excision and recurrence rates. RESULTS: A total of 23 (10 male and 13 female) patients, aged between 28 and 72 (mean, 46) years, underwent excision of 25 lesions during the study period. The mean duration of symptom was 2.5 years and tumour size ranged from 1 to 10.5 cm (mean, 2.6 cm). A majority (80%) presented with a typical triad; only one had a true neurological deficit. Twenty-two ultrasonography and 20 magnetic resonance images were obtained, with a diagnostic accuracy of 77% and 100%, respectively. Eight fine-needle aspiration cytology examinations and two core biopsies were performed, which had respective accuracy rates of 13% and 100%. Fifteen patients experienced neurological deficits after the operation; three showed spontaneous recovery. Among 12 patients with long-term residual neurological sequelae, five had both motor and sensory deficits and four had moderate-to-severe disability. No recurrence was reported. CONCLUSION: Nerve sheath tumours in the hand need to be managed with care. Among the different investigation modalities, magnetic resonance imaging was considered to be the gold standard. Yet ultrasonography is still the most easily accessible and least invasive investigation in public hospital setting. Complications are liable to ensue even if patients are managed by hand specialists. Thus, well-planned operations and detailed discussions with the patient are important prerequisites before operation.

Functional Outcome for Arthroscopic Treatment of Septic Arthritis of the Wrist.

Background Septic arthritis is a potentially joint-destructing condition if not treated properly. Septic wrist accounts for ∼5% of all septic arthritis. Arthroscopic lavage is a well-documented treatment for septic arthritis of the knee, hip, or shoulder only. Previous studies on septic wrist were limited to case reports or retrospective studies focusing on open treatment, and functional outcome was seldom documented. Our study aims to evaluate the effectiveness of arthroscopic treatment and to investigate the functional outcome. Materials and Methods Patients were retrospectively reviewed over a period of 10 years. Parameters including age, gender, history of prior injury, duration of symptoms, joint aspirates and intraoperative tissue culture, radiological and arthroscopic findings, antibiotics used, number of operations, and hospital stay were reviewed. Functional outcomes were evaluated with QuickDASH (disabilities of the arm, shoulder, and hand) score. Results From 2007 to 2016, 14 patients (15 septic wrists) underwent arthroscopic surgery. One patient had bilateral involvement. The average age was 63.9 years and the average duration of symptoms was 6.08 days. Average follow-up time was 10 months. All except two patients (85.7%) responded to single arthroscopic treatment. Two required subsequent operations for concomitant tenosynovitis. There were no major complications. The most common isolated organism was Staphylococcus aureus . Only one case had severe joint erosion during follow-up. The average QuickDASH score was 19.7. Duration of symptoms 5 days or more before admission was associated with higher QuickDASH score ( p = 0.04). Conclusion Early arthroscopic treatment should be considered for all patients admitted for septic arthritis of the wrist if not contraindicated. Level of Evidence This is a Level III, retrospective review.

Intraosseous glomus tumor treated by toe-to-finger transfer: case report.

We report a case of intraosseous glomus tumor that developed in the right ring finger distal phalanx of a 19-year-old man. Clinical and radiographic findings were atypical. The tumor was excised en bloc because of the extensive involvement. The left second toe was transferred to the right ring finger to reconstruct the excised finger part. Symptom relief, function, and cosmetic outcome were satisfactory during 2-year follow-up.

Needle aponeurotomy for Dupuytren's contracture.

PURPOSE: To review the efficacy and safety of needle aponeurotomy for Dupuytren's contracture in Chinese patients. METHODS: Seven men and one woman aged 50 to 80 (mean, 67) years underwent needle aponeurotomy for Dupuytren's contracture. Five were manual workers and the other 3 were retired. Their chief complaints were difficulty moving the fingers, clumsiness of the hand, and occasional pain in the palm. No patient had any family history of Dupuytren's contracture. RESULTS: 41 points were released in 13 fingers (3 middle, 3 ring, and 7 little). Immediately after release, the respective mean flexion contracture correction of the metacarpophalangeal and proximal interphalangeal joints were 50 (from 50 to 0) and 35 (from 46 to 11) degrees. At 22-month follow-up, the respective mean residual flexion contracture of both joints were 12 and 27 degrees; the corresponding long-term improvements were 70 and 41%. No patient had a wound complication or neurovascular injury. All had a normal score for Disabilities of the Arm, Shoulder, and Hand. CONCLUSION: For Chinese patients with Dupuytren's contracture, needle aponeurotomy is safe and effective. Long-term correction is better maintained in metacarpophalangeal than proximal interphalangeal joints (70 vs 41%).

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.

Reconstruction of hypoplastic thumb using hemi-longitudinal metatarsal transfer.

The treatment of hypoplastic thumb (modified Blauth's type IIIb and IV) by pollicization is culturally unfavourable in the Chinese population and digit preservation is preferred. An innovative reconstruction method using a nonvascularized hemi-longitudinal metatarsal graft was performed in six cases with an average follow-up of 87.7 months. Overall hand function was good, as assessed using the Jebsen hand function test. Grip strength and pinch power were significantly weaker than the normal contralateral hand. There was no neurovascular or wound complication. The only donor site complication was a metatarsal fracture, which healed uneventfully with casting. There had been no permanent morbidity to the donor site, as all donor metatarsals hypertrophied and regained normal growth potentials. Linear growth of the transferred metatarsals was evident radiologically (average 1.5 mm/year). Free hemi-longitudinal metatarsal transfer is a feasible method with good functional outcome in the attainment of a 5-digit hand in patients with type IIIb/IV hypoplastic thumb.

Enhanced localization of osteoid osteoma with radiolabeling and intraoperative gamma counter guidance: a case report.

Osteoid osteoma is a benign bone tumor that can be removed by marginal excision. Excessive removal of reactive bone may result in significant morbidity. We made use of the highly specific radioactive technetium uptake characteristic of osteoid osteoma for its localization. Radioactive technetium (25 mCi) was injected intravenously 2 hours before surgery to a 21-year-old male patient with an osteoid osteoma over the left distal radius. Tumor tissue was localized intraoperatively by a portable hand-held radioactive gamma counter to detect a focal high intensity of radioactivity. Complete tumor removal was shown by reduction of radioactivity to background level. This was confirmed by bone scintigraphy of the specimen and the forearm immediately after surgery. The defect was packed with cancellous bone graft taken from the ipsilateral distal radius through the same wound. Postoperative recovery was very satisfactory. We found this approach useful in limiting resection margin and surgical site morbidity in resection of osteoid osteoma.