Clinical Results of Arthroscopic Partial Trapeziectomy With Suture-Button Suspensionplasty for Thumb Carpometacarpal Arthritis.

BACKGROUND: This study represents the clinical results, especially range of motion (ROM) improvement, of arthroscopic partial trapeziectomy with suture-button suspensionplasty for symptomatic grade II and III thumb carpometacarpal arthritis with a minimum 1-year follow-up. METHODS: Thirty-two patients (mean: 67.5 years) with grade II and III thumb carpometacarpal arthritis treated with arthroscopic partial trapeziectomy with suture-button suspensionplasty were retrospectively followed up for at least 1 year. The physical assessments included ROM, pain visual analogue scale (VAS), strength, and the Disabilities of the Arm, Shoulder, and Hand (DASH) questionnaire. The physical variables were retrospectively compared before surgery and at the final follow-up. RESULTS: Preoperative radial abduction and palmar abduction (45.4 ± 16.4° and 54.3 ± 13.9°, respectively) were significantly increased at the final follow-up (59.7 ± 16.9° and 65.5 ± 14.2°, respectively). Preoperative VAS score, pinch strength, and DASH score (70.5 ± 14.0, 57.2 ± 24.8% and 36.8 ± 14.8, respectively) were also significantly improved at the final follow-up (7.9 ± 9.1, 91.0 ± 39.6%, and 11.7 ± 10.5, respectively). Complications involved 1 case of irritation of the superficial branch of the radial nerve and 1 case of dystonia. Two suture-buttons were removed due to patient discomfort. CONCLUSIONS: A significant increase in ROM and pain relief was obtained after suture-button suspensionplasty with arthroscopic partial trapeziectomy.

Reliability of antinuclear matrix protein 2 antibody assays in idiopathic inflammatory myopathies is dependent on target protein properties.

A line blotting assay (LB) is currently used to detect myositis-specific autoantibodies (MSAs) in patients with idiopathic inflammatory myopathies (IIMs), because of its simplicity; however, the sensitivity and specificity of this assay is low. The aim of this study is to evaluate the accuracy of the commercial LB in detection of antinuclear matrix protein 2 (NXP2) antibody. Seventy-seven serum samples from patients with IIMs, in which anti-NXP2 antibodies were detected through immunoprecipitation and western blotting (IP-WB) using K562 cell lysate, were enrolled. All samples were assessed by LB and IP-WB using recombinant human NXP2 whole protein (rNXP2) produced by insect cells, and the positive rates of each assay were compared. Thirty-two samples (41.6%) showed false-negativity by LB, which includes 11 samples with negative results by IP-WB using rNXP2. Relative intensities of IP-WB using cell lysate were significantly higher in the samples with positive results by both LB and IP-WB using rNXP2, compared to samples with positive by IP-WB using rNXP2 but negative by LB. Three of 11 samples with negative results by both LB and IP-WB using rNXP2 revealed high antibody titers. Further, differences in post-transcriptional SUMOylation were observed between recombinant and natural NXP2 proteins. In conclusion, the LB showed low sensitivity for detection of anti-NXP2 antibody, an effect exacerbated at low titers of anti-NXP2 antibodies. Moreover, there appears to be differences in the reactivities of antibodies to recombinant and natural NXP2 proteins with different post-transcriptional modifications.

Anti-nuclear matrix protein 2 antibody-positive inflammatory myopathies represent extensive myositis without dermatomyositis-specific rash.

OBJECTIVES: Myositis-specific autoantibodies (MSAs) define distinct clinical subsets of idiopathic inflammatory myopathies (IIMs). The anti-nuclear matrix protein 2 (NXP2) antibody, a MSA detected in juvenile/adult IIMs, has been reported to be associated with a high risk of subcutaneous calcinosis, subcutaneous oedema and internal malignancies. The study aimed to clarify the clinical features of anti-NXP2 antibody-positive IIMs in detail. METHODS: This was a multicentre retrospective observational study on 76 anti-NXP2 antibody-positive patients. The antibody was detected via a serological assay using immunoprecipitation and western blotting. The patients were selected from 162 consecutive Japanese patients with IIMs. RESULTS: The cohort of anti-NXP2 antibody-positive IIMs included 29 juvenile patients and 47 adult patients. Twenty-seven (35.5%) patients presented with polymyositis phenotype without dermatomyositis-specific skin manifestations (heliotrope rash or Gottron sign/papules); this was more common in the adults than children (48.9% vs 15.8%, P < 0.01). Nine (11.8%) patients had subcutaneous calcinosis, and 20 (26.3%) patients had subcutaneous oedema. In addition, the proportion of patients with muscle weakness extending to the distal limbs was high (36 patients [47.4%]) in this cohort. Adult patients had a higher prevalence of malignancy than the general population (age-standardized incidence ratio of malignancies: 22.4). CONCLUSION: Anti-NXP2 antibody-positive IIMs, which include dermatomyositis sine dermatitis, are characterized by atypical skin manifestations and extensive muscular involvement.

Finger sensory impairment after elbow flexion reconstruction using concomitant nerve transfer from the median and ulnar nerves.

PURPOSE: Single and double fascicular nerve transfer using the ulnar or median nerve is performed to restore elbow flexion following injuries to the brachial plexus or nerve root. However, little is known regarding the postoperative changes involved in the sensory alteration of the hand after a single and double fascicular nerve transfer. We evaluated the sensory alteration of the hand in patients who underwent single and double fascicular nerve transfer for two years. METHODS: A total of five patients that underwent single or double fascicular nerve transfer participated in this study. The injury mechanism was avulsion (n = 2), stretching (n = 1), open injury (n = 1), and compression (n = 1). The touch sensation of the index and the little fingers before surgery at 6 months, 1 year, and 2 years after nerve transfer was evaluated using the Semmes-Weinstein monofilaments test (SWM-t). Muscle strength of the elbow flexion and the wrist flexion was evaluated. RESULTS: The touch sensation of the index finger at 24 months was equal to the preoperative evaluation. On the other hand, the touch sensation of the little finger at 24 months slightly improved compared to what it had been at the preoperative evaluation. Moreover, the median of the SWM-t score in the index and little finger at 24 months after surgery was beyond 3.61 that mean diminished light touch level. CONCLUSIONS: The results of this study indicate that the touch sensory deficit of the index and little fingers persist for up to 2 years after nerve transfer.

Crizotinib-Induced Abnormal Signal Processing in the Retina.

Molecular target therapy for cancer is characterized by unique adverse effects that are not usually observed with cytotoxic chemotherapy. For example, the anaplastic lymphoma kinase (ALK)-tyrosine kinase inhibitor crizotinib causes characteristic visual disturbances, whereas such effects are rare when another ALK-tyrosine kinase inhibitor, alectinib, is used. To elucidate the mechanism responsible for these visual disturbances, the responses to light exhibited by retinal ganglion cells treated with these agents were evaluated using a C57BL6 mouse ex vivo model. Both crizotinib and alectinib changed the firing rate of ON and OFF type retinal ganglion cells. However, the ratio of alectinib-affected cells (15.7%) was significantly lower than that of crizotinib-affected cells (38.6%). Furthermore, these drugs changed the response properties to light stimuli of retinal ganglion cells in some of the affected cells, i.e., OFF cells responded to both ON and OFF stimuli, etc. Finally, the expressions of ALK (a target receptor of both crizotinib and alectinib) and of MET and ROS1 (additional target receptors of crizotinib) were observed at the mRNA level in the retina. Our findings suggest that these drugs might target retinal ganglion cells and that the potency of the drug actions on the light responses of retinal ganglion cells might be responsible for the difference in the frequencies of visual disturbances observed between patients treated with crizotinib and those treated with alectinib. The present experimental system might be useful for screening new molecular target agents prior to their use in clinical trials.