Published papers

Background: Patients with massive rotator cuff tears often exhibit loss of active range of shoulder motion, which can interfere with activities of daily living. The risk factors for loss of motion remain largely unknown. Purpose: To clarify the predictive factors that affect the range of motion in chronic massive rotator cuff tears using multivariate analyses. Study Design: Case-control study; Level of evidence, 3. Methods: The authors retrospectively reviewed 204 consecutive patients who were evaluated at their institution with chronic massive rotator cuff tears. In this study, the dependent variable was determined to be active anterior elevation limited to ≤90° or external rotation (ER) with the arm at the side limited to ≤0°. Explanatory variables included age; sex; affected side; duration of symptoms; smoking history; existence of diabetes, hypertension, or rheumatoid arthritis; involved tendons; presence of a 3-tendon tear; rupture of the long head of biceps tendon; superior migration of the humeral head; and cuff tear arthropathy. Baseline variables that were observed to be significant in the univariate analyses were included in multivariate models, which used logistic regression to identify independent predictors of loss of motion. Results: Overall, 73 patients (35.8%) exhibited limited anterior elevation, and 27 (13.2%) exhibited limited ER. Multivariate analyses showed that inferior subscapularis tear (odds ratio [OR], 14.66; 95% CI, 2.95-72.93; P =.001), smoking (OR, 4.13; 95% CI, 1.94-8.79; P <.001), superior migration of humeral head (OR, 3.92; 95% CI, 1.80-8.53; P =.001), and 3-tendon tear (OR, 3.29; 95% CI, 1.32-8.20; P =.011) were significantly associated with the loss of anterior elevation. Teres minor tear (OR, 73.37; 95% CI, 9.54-564.28; P <.001) and superior migration of the humeral head (OR, 3.55; 95% CI, 1.04-12.19; P =.044) were significantly associated with loss of ER. Conclusion: In the current study, a history of smoking, type of torn tendons, and superior migration of the humeral head were associated with loss of active shoulder motion. In particular, the status of inferior subscapularis or teres minor contributed to the onset of pseudoparalysis in massive rotator cuff tears.

As massive rotator cuff tears progress, various radiographic changes occur; however, the factors associated with radiographic changes remain largely unknown. This study aimed to determine the factors that affect radiographic severity in massive rotator cuff tears using multivariate analyses. We retrospectively reviewed 210 shoulders with chronic massive rotator cuff tears. The dependent variables were superior migration of the humeral head (Hamada grades 2–3), narrowing of the glenohumeral joint (grade 4), and humeral head collapse (grade 5). Baseline variables that were significant in univariate analyses were included in multivariate models. There were 91, 59, 43, and 17 shoulders classified as Hamada grades 1, 2–3, 4, and 5, respectively. Multivariate analysis showed that infraspinatus tear (P = 0.015) and long head of biceps (LHB) tendon rupture (P = 0.007) were associated with superior migration of humeral head. Superior subscapularis tear (P = 0.003) and LHB tendon rupture (P < 0.001) were associated with narrowing of glenohumeral joint. Female sex (P = 0.006) and superior subscapularis tear (P = 0.006) were associated with humeral head collapse. This study identified the rupture of infraspinatus and LHB as risk factors of superior migration of humeral head, and the rupture of subscapularis and LHB and female sex as risk factors of cuff tear arthropathy.

Chitosan has various tissue regeneration effects. This study was designed to investigate the nerve regeneration effect of Schwann cell (SC)-encapsulated chitosan-collagen hydrogel nerve conduit (CCN) transplanted into a rat model of sciatic nerve defect. We prepared a CCN consisting of an outer layer of chitosan hydrogel and an inner layer of collagen hydrogel to encapsulate the intended cells. Rats with a 10-mm sciatic nerve defect were treated with SCs encapsulated in CCN (CCN+), CCN without SCs (CCN−), SC-encapsulated silicone tube (silicone+), and autologous nerve transplanting (auto). Behavioral and histological analyses indicated that motor functional recovery, axonal regrowth, and myelination of the CCN+ group were superior to those of the CCN− and silicone+ groups. Meanwhile, the CCN− and silicone+ groups showed no significant differences in the recovery of motor function and nerve histological restoration. In conclusion, SC-encapsulated CCN has a synergistic effect on peripheral nerve regeneration, especially axonal regrowth and remyelination of host SCs. In the early phase after transplantation, SC-encapsulated CCNs have a positive effect on recovery. Therefore, using SC-encapsulated CCNs may be a promising approach for massive peripheral nerve defects.

We report a rare case of severe osteolysis following metacarpophalangeal (MP) joint arthroplasty using silicone implants in a patient with rheumatoid arthritis. A 72-year-old woman presented with painless masses on the dorsum of the left hand 6 years after MP joint arthroplasty using Sutter-type silicone implants. Radiographic evaluation revealed implant-associated osteolysis and cortical perforation of the second to fifth metacarpals. Revision arthroplasty was performed using grommet-equipped Swanson-type silicone implants combined with synovectomy and iliac bone grafting for severe palmar bone loss. One year later, similar osteolysis occurred in the right hand, and revision arthroplasty was again performed using Swanson-type implants without the need for bone grafting. The postoperative course was uneventful, and no recurrence of osteolysis or implant-related complications was observed over a 7-year follow-up period. Silicone synovitis is a recognised complication of silicone implant arthroplasty, caused by wear debris triggering chronic inflammation and bone resorption. This case highlights the importance of early detection and intervention for implant-related osteolysis. In cases where bone defects remain manageable, revision with grommet-equipped silicone implants can be a viable and durable treatment option. Surgeons should be aware of this potentially severe complication, as delayed intervention may preclude the use of silicone implants altogether due to extensive bone loss.

Thoracic outlet syndrome (TOS) is caused by entrapment of the neurovascular bundle in the interscalene, costoclavicular, or subpectoral minor space. Compression in the interscalene or costoclavicular space with the first rib and scalene muscle leads to vascular and neurogenic TOS, whereas compression in the subpectoral minor space leads to pectoralis minor syndrome. Various surgical approaches exist for the treatment of TOS. The introduction and development of surgical approaches have minimized surgical invasiveness and complications. The reported approaches include transaxillary, supraclavicular, infraclavicular, posterior, combined transaxillary and supraclavicular, combined supraclavicular and infraclavicular (paraclavicular), endoscopic-assisted transaxillary, and video-assisted thoracoscopic approaches. In this review, we summarize the reported surgical approaches for TOS treatment, in terms of the history of the approach, surgical procedure, advantages and disadvantages, clinical outcomes, and complications. An adequate excision of compression structures, including the first rib and scalene muscles, provides satisfactory outcomes regardless of the approach selected, whereas an inadequate release of compression structures leads to failed or recurrent outcomes. Reducing the risk of complications is the most important aspect of TOS management. Surgery should be performed safely, with sufficient resection of compression structures. Additionally, the approach should be selected based on the surgeon's skill, surgeon's preferences, surgical invasiveness, cosmetic appearance, and the presence of special equipment, as well as other advantages and disadvantages of each approach.

Introduction/Aims: T2 magnetic resonance imaging (MRI) mapping has been applied to carpal tunnel syndrome (CTS) for quantitative assessment of the median nerve. However, quantitative changes in the median nerve before and after surgery using T2 MRI mapping remain unclear. We aimed to investigate whether pathological changes could be identified by pre- and postoperative T2 MRI mapping of the median nerve in CTS patients after open carpal tunnel release. Methods: This was a prospective study that measured median nerve T2 and cross-sectional area (CSA) values at the distal carpal tunnel, hamate bone, proximal carpal tunnel, and forearm levels pre- and postoperatively. Associations between T2, CSA, and nerve conduction latency were also evaluated. Results: A total of 36 patients with CTS (mean age, 64.5 ± 11.7 years) who underwent surgery were studied. The mean preoperative T2 values significantly decreased from 56.3 to 46.9 ms at the proximal carpal tunnel levels (p =.001), and from 52.4 to 48.7 ms at the hamate levels postoperatively (p =.04). Although there was a moderate association between preoperative T2 values at the distal carpal tunnel levels and distal motor latency values (r = −.46), other T2 values at all four carpal tunnel levels were not significantly associated with CSA or nerve conduction latency pre- or postoperatively. Discussion: T2 MRI mapping of the carpal tunnel suggested a decrease in nerve edema after surgery. T2 MRI mapping provides quantitative information on the median nerve before and after surgery.

Introduction/Aims: 3D magnetic resonance imaging (MRI) is a tool for visualizing and quantifying the volume of the median nerve; however, the diagnostic value of the volume of the median nerve for assessing CTS severity is unclear. This study aimed to evaluate the utility of 3T MRI combined with three-dimensional (3D) imaging to assess the cross-sectional volume (CSV) of the median nerve for diagnosing carpal tunnel syndrome (CTS) and determining its severity. Methods: We used MRI to measure the CSV of the median nerve in 95 patients with CTS and 26 healthy controls. CTS severity was graded according to the Padua classification, and differences in CSV according to severity were analyzed. Results: The mean CSVs for the severity groups were as follows: control, 22.4 mm3; minimal, 28.8 mm3; moderate, 34.4 mm3; severe, 53.6 mm3; and extreme, 48.3 mm3. CSV increased with CTS severity, with significantly higher values in the severe and extreme groups compared with the moderate, minimal, and control groups. Discussion: This study showed that the CSV of the median nerve increased with disease severity, both visually and in three dimensions. This helps to visually understand the severity of CTS, and the association between morphology and disease severity may contribute to a better understanding of the pathophysiology of CTS.

Introduction: Ectopic ossifications often occur in skeletal muscles or tendons following local trauma or internal hemorrhage, and occasionally cause severe pain that limits activities of daily living. However, mechanisms underlying their development remain unknown. Materials and methods: The right Achilles tendon in 8-week-old female or male mice was dissected. Some mice were injected intraperitoneally either with phosphate-buffered saline, dimethyl sulfoxide, cimetidine, rapamycin, celecoxib or loxoprofen for 10 weeks. One week after surgery, immunohistochemical analysis was performed for mTOR, TNFα or F4/80. Ten weeks after surgery, ectopic ossification at the tenotomy site was detected by 3D micro-CT. Results: Ectopic ossification was seen at dissection sites in all wild-type mice by dissection of the Achilles tendon. mTOR activation was detected at dissection sites, and development of ectopic ossification was significantly inhibited by administration of rapamycin, an mTOR inhibitor, to wild-type mice. Moreover, administration of the histamine 2 blocker cimetidine, which reportedly inhibits ectopic ossification in tendons, was not effective in inhibiting ectopic ossification in our models. TNFα-expressing F4/80-positive macrophages accumulate at dissection sites and that ectopic ossification of the Achilles tendon dissection was significantly inhibited in TNFα-deficient mice in vivo. Ectopic ossification is significantly inhibited by administration of either celecoxib or loxoprofen, both anti-inflammatory agents, in wild-type mice. mTOR activation by Achilles tendon tenotomy is inhibited in TNFα-deficient mice. Conclusion: The TNFα-mTOR axis could be targeted therapeutically to prevent trauma-induced ectopic ossification in tendons.

Background: Precision placement of implants in total elbow arthroplasty (TEA) using conventional surgical techniques can be difficult and riddled with errors. Modern technologies such as augmented reality (AR) and 3-dimensional (3D) printing have already found useful applications in many fields of medicine. We proposed a cutting-edge surgical technique, augmented reality total elbow arthroplasty (ARTEA), that uses AR and 3D printing to provide 3D information for intuitive preoperative planning. The purpose of this study was to evaluate the accuracy of humeral and ulnar component placement using ARTEA. Methods: Twelve upper extremities from human frozen cadavers were used for experiments performed in this study. We scanned the extremities via computed tomography prior to performing TEA to plan placement sites using computer simulations. The ARTEA technique was used to perform TEA surgery on 6 of the extremities, whereas conventional (non-ARTEA) techniques were used on the other 6 extremities. Computed tomography scanning was repeated after TEA completion, and the error between the planned and actual placements of humeral and ulnar components was calculated and compared. Results: For humeral component placement, the mean positional error ± standard deviation of ARTEA vs. non-ARTEA was 1.4° ± 0.6° vs. 4.4° ± 0.9° in total rotation (P = .002) and 1.5 ± 0.6 mm vs. 8.6 ± 1.3 mm in total translation (P = .002). For ulnar component placement, the mean positional error ± standard deviation of ARTEA vs. non-ARTEA was 5.5° ± 3.1° vs. 19.5° ± 9.8° in total rotation (P = .004) and 1.5 ± 0.4 mm vs. 6.9 ± 1.6 mm in total translation (P = .002). Both rotational accuracy and translational accuracy were greater for joint components replaced using the ARTEA technique compared with the non-ARTEA technique (P < .05). Conclusion: Compared with conventional surgical techniques, ARTEA had greater accuracy in prosthetic implant placement when used to perform TEA.

Objectives: This study aimed to compare the pre- and postoperative morphology of the median nerve using three-dimensional (3-D) MRI in patients with carpal tunnel syndrome (CTS). Methods: We assessed 31 patients with CTS who underwent open carpal tunnel release and T2*-weighted MRI of the wrist preoperatively and at 6 months postoperatively. The median nerve morphology was evaluated on the basis of the cross-sectional areas (CSAs) and cross-sectional volumes (CSVs). The association between these MRI findings and nerve conduction studies was also evaluated. Results: The mean preoperative CSA and CSV values at the proximal carpal tunnel level significantly decreased from 22.2 mm2 and 24.4 mm3 to 16.5 mm2 and 18.1 mm3, respectively, postoperatively. Median nerve swelling at the proximal carpal tunnel level was observed in 29 (94%) and 23 (74%) patients before and after surgery, respectively. The mean preoperative CSA and CSV values at the hamate level significantly increased from 9.9 to 12.3 mm2 and from 10.9 to 13.5 mm3 after surgery, respectively. Nerve narrowing at the hamate bone level was preoperatively observed in 28 (90%) patients and postoperatively in 21 (68%) patients. Preoperative CSA and CSV values at the proximal carpal tunnel were significantly associated with preoperative distal motor and sensory latency. Conclusions: Visual confirmation of the median nerve morphology using 3-D MRI is useful when considering postoperative recovery and explaining the nerve condition to the patients. Key Points: • The 3-D morphology of the median nerve after carpal tunnel release can be delineated using 3-D MRI. • Preoperative swelling of the median nerve in the 2-D and 3-D planes reflects the severity of carpal tunnel syndrome. • Visual confirmation of the median nerve morphology is useful when considering median nerve recovery after carpal tunnel release and for explaining the condition of the nerve to patients.

Background: This retrospective study was designed to evaluate a surgical treatment for swan neck deformity of the fingers involving the volar transfer of the lateral band using the transverse retinacular ligament. Methods: Ten patients who underwent this surgical procedure for swan neck deformity treatment and were followed up for a mean of 26 months (range: 12-65 months) were included in the study. The dorsally located lateral bands were transferred toward the volar aspect of the finger, and their position was maintained using the transverse retinacular ligament. Improvement of the snapping and swan neck deformity was confirmed by intraoperative active motion of the finger. The active range of motion of the affected finger was evaluated pre- and postoperatively. Results: Extension of the proximal interphalangeal (PIP) joint averaged 30° (range: 20°-40°) preoperatively and improved to -2° (range: -5°-0°) postoperatively. Extension of the distal interphalangeal (DIP) joint averaged -30° (range: -15° to -70°) preoperatively and improved to -15° (range: 0° to -55°) postoperatively. The mean improvement in range of motion of the DIP joint was 15° (range: 10°-25°). The flexion of both the PIP and DIP joint did not significantly change in any of the patients postoperatively. Conclusions: Surgical transfer of the lateral band using the transverse retinacular ligament is effective in correcting mild swan neck deformity. Hyperextension of the PIP joint is corrected well, but the severe extension lag of the DIP joint remains uncorrected postoperatively.

Rheumatoid arthritis (RA) is a chronic symmetric polyarticular joint disease that primarily affects the small joints of the hands and feet. The inflammatory process is characterized by infiltration of inflammatory cells into the joints, leading to proliferation of synoviocytes and destruction of cartilage and bone. In RA synovial tissue, the infiltrating cells such as macrophages, T cells, B cells and dendritic cells play important role in the pathogenesis of RA. Migration of leukocytes into the synovium is a regulated multi-step process, involving interactions between leukocytes and endothelial cells, cellular adhesion molecules, as well as chemokines and chemokine receptors. Chemokines are small, chemoattractant cytokines which play key roles in the accumulation of inflammatory cells at the site of inflammation. It is known that synovial tissue and synovial fluid from RA patients contain increased concentrations of several chemokines, such as monocyte chemoattractant protein-4 (MCP-4)/CCL13, pulmonary and activation-regulated chemokine (PARC)/CCL18, monokine induced by interferon-gamma (Mig)/CXCL9, stromal cell-derived factor 1 (SDF-1)/CXCL12, monocyte chemotactic protein 1 (MCP-1)/CCL2, macrophage inflammatory protein 1alpha (MIP-1alpha)/CCL3, and Fractalkine/CXC3CL1. Therefore, chemokines and chemokine-receptors are considered to be important molecules in RA pathology.

OBJECTIVES: To study the role of monocyte chemoattractant protein-4 (MCP-4)/CCL13 in the pathogenesis of rheumatoid arthritis (RA), we analysed the expression of MCP-4/CCL13 in chondrocytes, synovial fluid and serum from patients with RA and investigated the effect of MCP-4/CCL13 on the proliferation of synovial cells. METHODS: Human articular cartilage specimens were obtained from joints from RA and osteoarthritis (OA) patients and normal joints (controls). Transcript levels of MCP-4 in cartilage were determined by real-time polymerase chain reaction. Protein levels were measured by enzyme-linked immunoassay. Cultured fibroblast-like synoviocytes (FLS) were treated with various concentrations of recombinant MCP-4/CCL13 protein, and cell proliferation was evaluated with a viability assay. RESULTS: The gene expression of MCP-4 was significantly higher in cartilage from RA patients than in that from OA patients (P = 0.00902) and in normal cartilage (P = 0.00902). The concentration of MCP-4/CCL13 protein in serum from RA patients (mean 94.7 +/- 37.6 pg/ml) was significantly higher than in serum from OA patients (mean 49.2 +/- 31.2 pg/ml, P = 0.0051) and controls (mean 32.6 +/- 23.9 pg/ml, P = 0.0001). The concentration of MCP-4/CCL13 protein in synovial fluid from RA patients (mean 247.2 +/- 161.2 pg/ml) was also significantly higher than in that from OA patients (mean 29.6 +/- 50.5 pg/ml, P = 0.000019). Moreover, MCP-4/CCL13 enhanced the proliferation of FLS in a dose-dependent manner. CONCLUSIONS: MCP-4/CCL13 is highly expressed in RA joints at the mRNA and protein levels. Our results suggest that MCP-4/CCL13 is secreted from chondrocytes and activates the proliferation of rheumatoid synovial cells, thereby leading to joint destruction in RA.