Quantitative evaluation of natural progression of fatty infiltration and muscle atrophy in chronic rotator cuff tears without tear extension using magnetic resonance imaging

Background

The pathology of and mechanisms underlying muscle degeneration remain unclear. We aimed to quantitatively evaluate the natural changes in fatty infiltration and muscle atrophy in patients with chronic rotator cuff tears using 3-dimensional 2-point Dixon magnetic resonance imaging.

Methods

Thirty patients with nonoperatively observed rotator cuff tears without tear extension were evaluated using multiple magnetic resonance imaging examinations with a minimum interval of 2 years. The fatty infiltration ratio (%fat) and muscle volume of the rotator cuff muscles were compared between the 2 examinations in those with supraspinatus (SSP) tear <2 cm (<2 cm SSP group), SSP tear ≥2 cm (≥2 cm SSP group), and massive tear (massive group). The SSP) infraspinatus, and teres minor (ISP + TM), and subscapularis muscles were evaluated.

Results

The massive group showed a significantly greater %fat than the <2 and ≥2 cm SSP groups in the SSP (P = .002) and ISP + TM muscles (P < .001). The total muscle volume did not differ among the 3 groups for all rotator cuff muscle components. The %fat values did not change in any rotator cuff components during the follow-up period in all groups. The total muscle volume in the massive group significantly decreased in the SSP (P = .018) and ISP + TM muscles (P = .013).

Conclusion

The present results indicate that fatty infiltration of the torn muscle occurs in the early phase after a rotator cuff tear, whereas muscle atrophy appears to progress gradually in chronic rotator cuff tears. Early intervention before muscle degeneration should be considered if the tear involves the infraspinatus tendon.

Recent advances in unlinked total elbow arthroplasty in Japan

Background

Total elbow arthroplasty (TEA) is a valuable therapeutic approach for improving function and relieving pain in severely deformed elbow joints. However, TEA is associated with a high incidence of complications. In Japan, the use of unlinked TEA has a long history, with the development of the Kudo prosthesis marking a significant milestone. Subsequently, various unlinked implant designs have been developed. Although favorable long-term clinical results have been reported, complications remain a concern. To further improve the outcome of unlinked TEA, attempts have been made in recent years to develop various surgical approaches and intraoperative support devices. This review focuses on the clinical outcomes and recent advances in unlinked TEA in Japan.

Methods

A comprehensive review of clinical results and advancements in unlinked TEA in Japan was conducted. The analysis included trends in the number of TEA, medium-term and long-term results for unlinked TEA, surgical approaches, or preoperative planning techniques.

Results

Several implant designs have been developed in Japan. Clinical studies have reported satisfactory long-term outcomes with these implants, but complications, such as infection, fractures, and dislocation, have been observed. In order to enhance the outcomes of unlinked TEA, various triceps-on approaches have been developed as alternatives to the triceps-detaching approach, which compromises the continuity between the triceps tendon and ulna, leading to inevitable complications related to the triceps tendon. Preservation or repair of the surrounding soft tissues is considered critical for preventing postoperative instability due to the absence of a radial head in the current unlinked TEA design. Computed tomography-based 3-dimensional preoperative planning has been pioneered in Japan, demonstrating its effectiveness in predicting implant size and achieving appropriate implant placement. Additionally, augmented reality-assisted surgery is being explored to accurately translate preoperative planning into the surgical procedure.

Conclusion

Unlinked TEA for inflammatory arthritis has exhibited promising long-term results in Japan, with ongoing efforts to improve surgical techniques and preoperative planning. Further advancements are anticipated to prevent complications such as dislocation and peri-implant fractures.

Identifying prognostic biomarkers for palbociclib add-on therapy in fulvestrant-resistant breast cancer using cell-free DNA sequencing

BACKGROUND

The FUTURE trial (UMIN000029294) demonstrated the safety and efficacy of adding palbociclib after fulvestrant resistance in patients with hormone receptor-positive (HR+)/human epidermal growth factor receptor 2-negative (HER2-) advanced and metastatic breast cancer (ABC/MBC). In this planned sub-study, cancer panel sequencing of cell-free DNA (cfDNA) was utilized to explore prognostic and predictive biomarkers for further palbociclib treatment following fulvestrant resistance.

MATERIALS AND METHODS

Herein, 149 cfDNA samples from 65 patients with fulvestrant-resistant disease were analysed at the time of palbociclib addition after fulvestrant resistance (baseline), on day 15 of cycle 1, and at the end of treatment using the assay for identifying diverse mutations in 34 cancer-related genes.

RESULTS

During the course of treatment, mutations in ESR1, PIK3CA, FOXA1, RUNX1, TBX3, and TP53 were the most common genomic alterations observed. Analysis of genomic mutations revealed that before fulvestrant introduction, baseline PIK3CA mutations were marginally lower in metastatic aromatase inhibitor (AI)-treated patients compared to adjuvant AI-treated patients (P = 0.063). Baseline PIK3CA mutations were associated with poorer progression-free survival [hazard ratio: 1.62, P = 0.04]. Comparative analysis between baseline and early-changing gene mutations identified poor prognostic factors including early-changing MAP3K1 mutations (hazard ratio: 4.66, P = 0.04), baseline AR mutations (hazard ratio: 3.53, P = 0.04), and baseline PIK3CA mutations (hazard ratio: 3.41, P = 0.02). Notably, the relationship between ESR1 mutations and mutations in PIK3CA, MAP3K1, and TP53 weakened as treatment progressed. Instead, PIK3CA mutations became correlated with TP53 and FOXA1 mutations.

CONCLUSIONS

Cancer panel testing for cfDNA identified prognostic and predictive biomarkers for palbociclib add-on therapy after acquiring fulvestrant resistance in patients with HR+/HER2- ABC/MBC.

Extra-Articular Stabilization for the Treatment of Recurrent Sternoclavicular Joint Instability: A Report of Two Cases

CASE

A 22-year-old man and a 14-year-old adolescent boy, who exhibited moderate general joint laxity, experienced recurrent sternoclavicular joint instability without traumatic events. The patients were successfully treated with extra-articular stabilization using autologous tendon grafts without surgical exposure of the sternoclavicular joint.

CONCLUSION

Atraumatic instability of the sternoclavicular joint is rare but often results in recurrent instability accompanied by discomfort, pain, and limitations in activities. Extra-articular stabilization, which reinforces the anterior capsule of the sternoclavicular joint and prevents anterior displacement of the proximal clavicle at the elevated arm position, could be a viable surgical option for this pathological condition.

Alaska Pollock-derived Gelatin Sealant has Higher Sealing Strength than, and Comparable Biocompatibility with, Fibrin Sealant in Porcine and Rat Dural Injury Models

STUDY DESIGN

Burst strength study in porcine dural models and functional and histological study in rat dural models.

OBJECTIVE

This study aimed to investigate the sealing strength and biocompatibility of Alaska pollock-derived gelatin (ApGltn) and fibrin sealants in disrupted dural injuries.

SUMMARY OF BACKGROUND DATA

Disruption of the dura mater occurs during spine surgery, leading to cerebrospinal fluid leakage. Fibrin sealant is usually applied to ruptured sites; however, it lacks sealing strength. A novel biocompatible sealant composed of ApGltn was recently demonstrated to have good burst strength and biocompatibility in the porcine aorta.

METHODS

Ten porcine dura maters with central holes were covered with ApGltn and fibrin sealants (five samples per group). The maximum burst strength of each sealant was measured, and histological examination was performed after burst testing. Twenty-seven dura maters of male Wistar rats were used for functional and histopathological evaluations. The rats were treated with three surgical interventions: defect + ApGltn sealant; defect + fibrin sealant; defect alone (nine rats per group). Macroscopic confirmation of the sealant, hindlimb motor function analysis, and histopathological examination were performed at 2, 4, and 8 weeks after the procedure.

RESULTS

The maximum burst strength of the ApGltn sealant was approximately 4.4 times higher than that of the fibrin sealant (68.1±12.1 vs. 15.6±8.7 mmHg; P<0.001). Histological examination confirmed that the ApGltn sealant showed tight adhesion to the dural surface, whereas a gap was observed between the fibrin sealant and the dura mater. In the rat model, the ApGltn sealant resulted in spinal function and dural histological findings similar to those of the fibrin sealant.

CONCLUSIONS

The ApGltn sealant had a higher sealing strength than, and comparable effect on dura regeneration with, the fibrin sealant.

Volar Transfer of the Lateral Band With Transverse Retinacular Ligament for the Correction of Swan Neck Deformity

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.

Novel artificial nerve transplantation of human iPSC-derived neurite bundles enhanced nerve regeneration after peripheral nerve injury

BACKGROUND

Severe peripheral nerve damage always requires surgical treatment. Autologous nerve transplantation is a standard treatment, but it is not sufficient due to length limitations and extended surgical time. Even with the available artificial nerves, there is still large room for improvement in their therapeutic effects. Novel treatments for peripheral nerve injury are greatly expected.

METHODS

Using a specialized microfluidic device, we generated artificial neurite bundles from human iPSC-derived motor and sensory nerve organoids. We developed a new technology to isolate cell-free neurite bundles from spheroids. Transplantation therapy was carried out for large nerve defects in rat sciatic nerve with novel artificial nerve conduit filled with lineally assembled sets of human neurite bundles. Quantitative comparisons were performed over time to search for the artificial nerve with the therapeutic effect, evaluating the recovery of motor and sensory functions and histological regeneration. In addition, a multidimensional unbiased gene expression profiling was carried out by using next-generation sequencing.

RESULT

After transplantation, the neurite bundle-derived artificial nerves exerted significant therapeutic effects, both functionally and histologically. Remarkably, therapeutic efficacy was achieved without immunosuppression, even in xenotransplantation. Transplanted neurite bundles fully dissolved after several weeks, with no tumor formation or cell proliferation, confirming their biosafety. Posttransplant gene expression analysis highlighted the immune system's role in recovery.

CONCLUSION

The combination of newly developed microfluidic devices and iPSC technology enables the preparation of artificial nerves from organoid-derived neurite bundles in advance for future treatment of peripheral nerve injury patients. A promising, safe, and effective peripheral nerve treatment is now ready for clinical application.

Point of care ultrasound combined with CTS-6 to diagnose idiopathic carpal tunnel syndrome

BACKGROUND

This study aimed to demonstrate the effectiveness of our new diagnostic chart using point of care ultrasound combined with CTS-6 for diagnosing idiopathic carpal tunnel syndrome.

METHODS

We conducted a retrospective analysis of the data of patients who visited our department and received point of care ultrasound combined with CTS-6 from 2020 to 2023. Data regarding age, sex, initial and final diagnosis, cross-sectional area of the median nerve, CTS-6 score, and electrodiagnostic severity were obtained and statistically analyzed.

RESULTS

Of the 177 wrists included in our study, 138 (78 %) were diagnosed with carpal tunnel syndrome, while 39 (22 %) were not (non-carpal tunnel syndrome). With our diagnostic method, 127 wrists (72 %) were diagnosed initially with carpal tunnel syndrome, 23 wrists (13 %) with non-carpal tunnel syndrome, and the rest 27 wrists (15 %) as borderline. Our initial diagnoses of carpal tunnel syndrome and non-carpal tunnel syndrome were maintained in all cases except for two. Cross-sectional area, CTS-6 score, and electrodiagnostic severity showed a positive correlation. A post hoc analysis showed that the new scoring system (CTS-6 score + 2 × cross-sectional area) with a cutoff value of 31.25 points showed a sensitivity as high as 95 % and a specificity of 100 %.

CONCLUSIONS

Our findings suggest that most suspected idiopathic carpal tunnel syndrome cases can be diagnosed correctly using the diagnostic chart. Although additional tools, including electrodiagnostic studies, may be needed for borderline cases, the use of point of care ultrasound combined with CTS-6 may be a recommendable first-line confirmatory test because point of care ultrasound and CTS-6 could be complementary tools, and this chart may be especially beneficial for atypical or outlier cases.

LEVEL OF EVIDENCE

Diagnostic III.

In-vivo kinematics of the trapeziometacarpal joint in dynamic pinch motion using four-dimensional computed tomography imaging

OBJECTIVE

CT imaging precisely and quantitatively analyzes the kinematics of the carpal bones to evaluate the etiology of related osteoarthritis. Previous studies have investigated the kinematics of the trapeziometacarpal joint using static CT scans of various postures including the pinch position. This study analyzed the in-vivo kinematics of the trapeziometacarpal joint during dynamic pinch motion in young healthy volunteers using four-dimensional CT.

MATERIALS AND METHODS

Twelve healthy young volunteers participated in this study. Each participant held the pinch meter between their thumb and index finger and pinched it with maximum force for a period of 6 s. This series of movement was recorded using a four-dimensional CT. The surface data of the trapezium and first metacarpal of all frames were reconstructed, and bone movement at the trapeziometacarpal joint was calculated using sequential three-dimensional registration. The instantaneous pinch force of each frame was measured using a pointer on a pinch meter that was reconstructed from the CT data.

RESULTS

The first metacarpal was abducted (15.9 ± 8.3°) and flexed (12.2 ± 7.1°) relative to the trapezium, and significantly translated to the volar　(0.8 ± 0.6 mm) and ulnar directions (0.9 ± 0.8 mm) with maximum pinch force. This movement consistently increased with the pinch force.

CONCLUSION

This study successfully employed 4D-CT to precisely demonstrate changes in rotation and translation at the trapeziometacarpal joint during pinch motion for various instantaneous forces.

Painful snapping of the middle finger caused by hyperplasia of the ulnar lateral band: A case report

Snapping of fingers can be caused by pathologies such as stenosing flexor tenosynovitis. However, snapping symptoms in the metacarpophalangeal (MP) joint caused by hypertension and hyperplasia of the lateral band are rare. We present a 26-year-old female with symptoms of painful snapping of the middle finger. When the finger was actively flexed from the hyperextension of the MP joint, the ulnar lateral band was prominent, and a snapping phenomenon occurred. The cause of the snapping finger was considered to be tightness of the ulnar lateral band, and surgery was planned. Intraoperatively, the ulnar lateral band was tense and hyperplastic. The snapping phenomenon disappeared immediately after the resection of the lateral band. It is important to consider this condition as one of the differential diagnoses of snapping finger when the patient complains of an atypical snapping phenomenon.

Rupture of the Flexor Pollicis Longus Tendon Involved between the Radial Shaft and the Volar Locking Plate

We report the case of a 61-year-old woman with right-sided flexor pollicis longus (FPL) tendon ruptured a month after volar locking plate fixation. Five months after the initial operation, hardware removal and reconstruction of the FPL tendon with the ipsilateral palmaris longus were performed. The proximal stump of the ruptured FPL tendon was found in the space between the distal radius and plate.

Long-standing Ulnar Wrist Pain Caused by an Anatomic Variant of the Ulnar Nerve: A Case Report

CASE

We present a 28-year-old woman with long-standing left ulnar wrist pain. Physical examination revealed severe tenderness over the pisiform; imaging findings were normal. Surgical exploration revealed compression of an aberrant branch, likely Kaplan's accessory branch, around the pisiform. Complete symptom relief was achieved after nerve decompression.

CONCLUSION

Clinical symptoms associated with Kaplan's accessory branch are rare, indicating that many branches may be asymptomatic or overlooked despite the presence of symptoms. Kaplan's accessory branch should be considered as a potential differential diagnosis for refractory ulnar wrist pain.

TNFα-dependent mTOR activity is required for tenotomy-induced ectopic ossification in mice

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.

Press-Fit Hemihamate Arthroplasty for the Proximal Interphalangeal Joint

Background  Chronic proximal interphalangeal joint fracture-dislocations with articular malunion are complex injuries. Hemihamate arthroplasty is an established technique for the management of both acute and chronic cases but is associated with several complications. We present the clinical experience of modified press-fit hemihamate arthroplasty. Description of Technique  The base of the middle phalanx was exposed from the volar side, and the cartilage defect of the proximal interphalangeal joint (PIPJ) was evaluated in the hyperextended position. A bone hole was created slightly toward the volar side to recreate the curvature of the PIPJ. The hemihamate osteochondral graft was harvested and fixed into the bone hole in a press-fit manner without using a screw. The volar plate and flexor tendon sheath were then reattached. Patients and Methods  The study included three patients with chronic dorsal fracture-dislocations of the PIPJ. All patients were treated for >6 weeks after the injury (average 11 weeks). Results  The average total arc of motion of the affected joint improved from 38 degrees before surgery to 80 degrees after surgery. Radiographically, bone union and congruity of the joint surface were achieved in all the patients. None of the treated patients complained of resting pain and reported minimal pain during activity (average visual analog scale 0.5; range 0-1.4). Conclusions  Press-fit hemihamate arthroplasty is a safe and effective procedure for treating chronic PIPJ fracture-dislocations without the risk of screw protrusion.

Persistent Ulnar Nerve Palsy with Cubitus Valgus Deformity Following a Surgically Treated Flexion-type Supracondylar Humeral Fracture - A Case Report

Introduction

Supracondylar humeral fractures (SHFs) in children are mostly extension-type. SHFs have a high risk of cubitus varus deformity, while valgus deformity is rarely described. Nerve palsy can also occur during or after the injury, with most cases recovering spontaneously. Here, we present a rare case of cubitus valgus deformity after a flexion-type SHF with ulnar nerve (UN) palsy, which was successfully treated by corrective osteotomy and anterior transposition of the UN.

Case Report

A 10-year-old girl had left-sided cubitus valgus deformity with persistent UN palsy 4 months after open reduction and internal fixation (ORIF) at another hospital. Half a year after the initial operation, corrective osteotomy of the distal humerus with neurolysis and subcutaneous anterior transposition of the UN were performed. She showed excellent recovery 14-month postoperatively and reported restored motor and sensory function with symmetrical elbow appearance.

Conclusion

Surgeons usually observe the elbow angle carefully to avoid cubitus varus deformity. However, when treating a case of flexion-type SHFs, ORIF should be conducted to avoid cubitus valgus deformity, which could potentially cause UN traction as well as cosmetic dissatisfaction.

Influence of Electrodiagnostic Studies on Surgery for Carpal Tunnel Syndrome: A Retrospective Analysis of Data from a Single Urban Institution

Background: This study aimed to clarify the influence of preoperative electrodiagnostic (EDX) utilisation and its severity on surgically treated patients with carpal tunnel syndrome (CTS). Methods: This retrospective study analysed the data of patients who underwent CTS surgery at our facility from 2012 to 2022. Data regarding age, sex, affected side, diabetes mellitus, rheumatoid arthritis, haemodialysis and insurance type were collected, along with the following clinical information: utilisation of EDX, steroid injection, number of items of preoperative physical examination and history taking, intervals between symptom onset and the initial visit and between the initial visit and surgery, type of surgical procedure and surgery categorisation (primary or revision). EDX data (EDX severity, interval between EDX and surgery and concomitant nerve lesions) were also investigated. Univariate and multivariate analyses were conducted to assess the influence of EDX utilisation and severity on clinical parameters. Results: Of the 343 hands enrolled in our study, 304 (89%) underwent preoperative EDX assessment. EDX severity was classified as normal, mild, moderate or severe in 6 (2%), 18 (6%), 102 (34%) and 178 hands (58%), respectively. After the univariate and multivariable analyses, more items of preoperative physical examination and history taking were associated with non-EDX utilisation, whereas younger age, female sex and steroid injection were associated with milder EDX. Conclusions: Increased number of items of preoperative physical examination and history taking or steroid injection were independently associated with non-EDX utilisation or milder EDX, respectively, suggesting that when thorough clinical evaluation is conducted, hand surgeons may be less likely to request for EDX before surgery. Moreover, their treatment recommendation may be influenced by EDX severity. Level of Evidence: Level III (Diagnostic).

Schwann cell-encapsulated chitosan-collagen hydrogel nerve conduit promotes peripheral nerve regeneration in rodent sciatic nerve defect models

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.

Factors Associated with Change in Diagnosis of Carpal Tunnel Syndrome after Electrodiagnostic Studies

Background: Hand surgeons sometimes place more weight on clinical findings and may not always consider the results of electrodiagnostic studies (EDX) in the diagnosis of carpal tunnel syndrome (CTS). The aim of this study is to determine factors associated with a change in diagnosis of CTS after EDX. Methods: This is a retrospective study of all patients with an initial clinical diagnosis of CTS who underwent EDX at our hospital. We identified patients whose diagnosis changed from CTS to non-CTS after EDX and used univariate and multivariate analysis to determine if age, sex, hand dominance, unilateral symptoms, history of diabetes mellitus, rheumatoid arthritis, haemodialysis, cerebral lesion, cervical lesion, mental disorder, initial diagnosis by a non-hand surgeon, the number of examined items in CTS-6 and a CTS-negative EDX result were associated with a change in diagnosis after EDX. Results: A total of 479 hands with a clinical diagnosis of CTS underwent EDX. The diagnosis was changed to non-CTS in 61 hands (13%) after EDX. Univariate analysis demonstrated that unilateral symptoms, cervical lesion, mental disorder, initial diagnosis by a non-hand surgeon, the number of examined items and a CTS-negative EDX result were significantly associated with a change in diagnosis. In the multivariate analysis, only the number of examined items was significantly associated with a change in diagnosis. Conclusions: EDX results were particularly valued in hands where the initial diagnosis was uncertain for CTS. In hands with an initial diagnosis of CTS, the performance of sufficient history-taking and physical examination was more valued at the final diagnosis than EDX results or other aspects of the patient's background. The process of confirming a clear initial clinical diagnosis of CTS using EDX may be of little value for decision-making at the final diagnosis. Level of Evidence: Level III (Therapeutic).

Distal Radioulnar Joint Locking with Bipolar Injury

Background  Locking of the distal radioulnar joint (DRUJ) induces restriction of the active and passive motion of pronation or supination of the forearm. Diagnosis of DRUJ locking due to a triangular fibrocartilage complex (TFCC) tear is sometimes difficult. Case Description  A 15-year-old female suffered from restriction of forearm supination after cast immobilization for the treatment of an elbow injury. The active and passive range of motion (ROM) of supination was 30 degrees, while the active ROM of pronation was normal. Radiographs of the elbow showed a fracture of the medial epicondyle and a fracture around the radial head. Radiographs of the wrist showed a subluxation of the ulnar head. Accurate diagnosis of supination restriction was difficult before surgery, so an operation was performed for the diagnosis and treatment. DRUJ locking was reduced manually and arthroscopic findings showed central perforation of the TFCC. Forearm supination improved to 90 degrees postoperatively. Literature Review  DRUJ locking due to a TFCC injury is rare and this condition with bipolar injury has not been reported. Clinical Relevance  DRUJ locking due to an injured TFCC should be considered as one of the differential diagnoses of supination contracture.

GC-MS analysis of exhaled gas for fine detection of inflammatory diseases

Exhaled gas analysis is a non-invasive test ideal for continuous monitoring of biological metabolic information. We analyzed the exhaled gas of patients with inflammatory diseases for trace gas components that could serve as biomarkers that enable early detection of inflammatory diseases and assessment of treatment efficacy. Furthermore, we examined the clinical potential of this method. We enrolled 34 patients with inflammatory disease and 69 healthy participants. Volatile components from exhaled gas were collected and analyzed by a gas chromatography-mass spectrometry system, and the data were examined for gender, age, inflammatory markers, and changes in markers before and after treatment. The data were tested for statistical significance through discriminant analysis by Volcano plot, Analysis of variance test, principal component analysis, and cluster analysis comparing healthy and patient groups. There were no significant differences in the trace components of exhaled gas by gender or age. However, we found differences in some components of the exhaled gas between healthy and untreated patients. In addition, after treatment, gas patterns including the patient-specific components changed to a state closer to the inflammation-free status. We identified trace components in the exhaled gas of patients with inflammatory diseases and found that some of these regressed after treatment.

Hybrid Tension Band Wiring for Olecranon Fractures

Tension band wiring (TBW) is a standard surgical technique for treating olecranon fractures (OFs). We devised a hybrid TBW (HTBW) combining TBW using wires with eyelets and cerclage wiring. Twenty-six patients with isolated OFs with Colton classification groups 1-2C were subjected to HTBW, and the data was compared with those treated with conventional TBW (38 patients). The mean operation time and hardware removal rate were 51 versus 67 minutes (p < 0.001) and 42% versus 74% (p < 0.012), respectively. The HTBW group had one patient (4%) with surgical wire breakage. The conventional TBW group had 14 patients (37%) with symptomatic backout of Kirschner wires, three patients (8%) with loss of reduction, two patients (5%) with surgical site infection and one patient (3%) with ulnar nerve palsy. The motion and functional score ranges of the elbow were not significantly different. Therefore, this procedure may be a feasible alternative. Level of Evidence: Level V (Therapeutic).

Artificial Lunate Arthroplasty for Kienböck Disease With Multiple Extensor Tendon Ruptures: A Case Report

CASE

A 73-year-old woman presented with wrist pain and loss of extension in the middle and ring fingers. Radiography revealed a dorsally displaced lunate fragment, resulting in a diagnosis of Kienböck disease with extensor tendon rupture. Artificial lunate replacement and tendon transfer were performed as treatment. Two years postoperatively, the pain was relieved, and the extension lag was 0°. The wrist motion and carpal height had also improved.

CONCLUSION

Lunate excision, partial wrist arthrodesis, or proximal row carpectomy are known treatments for Kienböck disease with extensor tendon rupture. Lunate arthroplasty is a novel, useful treatment option for this condition.

Comparative study on the effectiveness of bone grafting for arthrodesis of the thumb carpometacarpal arthritis

The aim of this retrospective study was to assess the effectiveness of autogenous bone grafting for arthrodesis of the thumb carpometacarpal joint by comparing the bone union rates with and without bone grafting. We included 36 patients who underwent arthrodesis of the thumb carpometacarpal joint for arthritis (20 patients with bone grafts and 16 without bone grafts). Implants used for internal fixation were K-wire, tension band wiring, headless compression screw and locking plate. The presence of bone union and the time from surgery to bone union were evaluated. The bone union rate was 20/20 (100%) in the bone grafting group and 12/16 (75%) in the non-bone grafting group (p = 0.03). There were no significant differences between the two groups in the time from surgery to bone union and patient characteristics. In conclusion, autogenous bone grafting may contribute to the bone union in the arthrodesis of thumb carpometacarpal arthritis.Level of evidence: III.

Endoscopic-assisted Infraclavicular Approach for First-Rib Resection in Neurologic Thoracic Outlet Syndrome: A Report of Two Cases

Various reported surgical approaches for the treatment of thoracic outlet syndrome (TOS) exist and no firm evidence exists for any approach. A 16-year-old and a 29-year-old male presented with numbness in the upper limb. Neurologic TOS was diagnosed, and surgery was planned for the resection of the first rib and scalene muscles. Through an infraclavicular incision, open resection of the anterior scalene muscle and the anterior aspect of the first rib was performed. With the assistance of endoscopy, the middle scalene muscles and the posterior aspect of the first rib were resected. Preoperative symptoms improved after surgery without any complications. The endoscopic-assisted infraclavicular approach enabled resection of the first rib and scalene muscles, leading to satisfactory outcomes. Level of Evidence: Level V (Therapeutic).

Investigation of in-line filter replacement intervals for infusion

BACKGROUND

In-line filters in peripheral and central venous catheters are used to remove bacterial cells mechanically. A recent study indicated an extension of the use of infusion sets to 7 days. There is no evidence regarding replacement intervals for in-line filters.

AIM

To test in-line filters that were used continuously for 7 days in order to investigate their ability to remove bacteria and assess the flow rate.

METHODS

Three different in-line filters were attached to an ELNEOPA-NF No. 2 premixed infusion bag of intravenous hyperalimentation, into which Staphylococcus epidermidis ATCC12228 or Escherichia coli ATCC25922 was inoculated. These experiments were compared with a control infusion. The infusion was dropped at a flow rate of 40 mL/h and replaced at 24-h intervals for 7 days. Samples were collected 24 h after drop initiation.

FINDINGS

S. epidermidis was not detected in droplets between Days 1 and 6, but In-line filters 1 and 2 showed droplets containing 6-10 colony-forming units/mL on Day 7. E. coli was not detected in any of the filters after 7 days of continuous use. Flow rates <40 mL/h were observed on Day 7 for In-line filter 3 in studies of S. epidermidis, and on Days 4 and 3 for In-line filters 2 and 3, respectively, in studies of E. coli.

CONCLUSION

This study revealed differences in bacterial removal and flow rates under high inoculation between the three in-line filters tested. It is suggested that in-line filters can be used continuously for a maximum of 6 days, and reductions in flow rate after 48 h of continuous use should be noted carefully.

Modified Thompson-Littler Method for Chronic Instability of the Proximal Interphalangeal Joint: A Report of Two Cases

A 40-year-old patient and a 45-year-old patient presented with chronic dorsal and lateral subluxation of the proximal interphalangeal (PIP) joint of the little finger and underwent surgeries. Through a dorsal approach, the ulnar lateral band was transected and transferred to the radial side through the volar side of the PIP joint. The transferred lateral band and the remnant of the radial collateral ligament were secured with an anchor on the radial side of the proximal phalanx. Satisfactory results were obtained without the loss of flexion and recurrence of subluxation of the finger. This method enabled the correction of both dorsal and lateral instability of the PIP joint through a dorsal incision. The modified Thompson-Littler technique was useful for chronic instability of the PIP joint.- Level of Evidence: Level V (Therapeutic).

Excision of the hook of hamate in athletes using the carpal tunnel approach

BACKGROUND

Hook of the hamate fractures can be managed conservatively or fixed using a screw, but excision is recommended for prompt return to activities. Although various approaches have been described, there is no gold standard. Herein, the authors have described their clinical experiences in excising the hook of the hamate using the carpal tunnel approach, in athletes.

METHODS

A total of 36 athletes underwent excision of the hamate hook using the carpal tunnel approach. The mean age of the patients was 23 years, and most of them were baseball players (n = 31).

RESULTS

The mean operation time was 33 min. None of the patients presented with any complications aside from transient pillar pain in five cases. All of them returned to their sports activities within an average of 27 days.

CONCLUSIONS

In our study, excision of the hook of the hamate was performed safely via the carpal tunnel. The carpal tunnel approach reportedly provides superior benefits over other approaches.

In Vivo Metacarpophalangeal Joint Kinematics After Silicone Implant Arthroplasty in Patients With Rheumatoid Arthritis

PURPOSE

The aim of this study was to determine the potential mechanism of implant fracture using 3-dimensional motion analysis of patients with rheumatoid arthritis.

METHODS

Active flexion motion in 9 hands (34 fingers) of 6 female patients with rheumatoid arthritis who previously underwent hinged silicone metacarpophalangeal joint arthroplasty was examined using 4-dimensional computed tomography. Positions of the proximal phalanges relative to the metacarpals were quantified using a surface registration method. The deformation of the silicone implant was classified in the sagittal plane in the maximum flexion frame. The longitudinal bone axis of the proximal phalanx and the helical axis of the proximal phalanx were evaluated in 3-dimensional coordinates based on the hinge of the silicone implant.

RESULTS

Nineteen fingers were classified into group 1, in which the silicone implant moved volarly during flexion without buckling of the distal stem. Twelve fingers were classified into group 2, in which the distal stem of the silicone implant buckled. Three fingers were classified into group 3, in which the base of the distal stem had already fractured. Quantitatively, the longitudinal bone axes of the proximal phalanges were displaced from dorsal to volar in the middle stage of flexion and migrated in the proximal direction in the late phase of flexion. The helical axes of the proximal phalanges were located on the dorsal and proximal sides of the hinge, and these tended to move in the volar and proximal directions as the metacarpophalangeal joint flexed.

CONCLUSIONS

Volar and proximal translation of the proximal phalange was observed on 4-dimensional computed tomography.

CLINICAL RELEVANCE

Proximal displacement of the bone axis late in flexion appears to be a contributing factor inducing implant fractures, because the pistoning motion does not allow the implant to move in the proximal direction.

A case of neuropathic arthropathy of the elbow with early loosening after total elbow arthroplasty

We reported the case of a 65-year-old woman who presented with neuropathic arthropathy of the elbow and had undergone cervical spinal cord tumour resection at 32 years of age. Open synovectomy with free-body resection was performed; however, the instability of the elbow joint rapidly progressed. Therefore, we performed total elbow arthroplasty using a linked-type prosthesis. However, the humeral stem severely loosened 1 year after arthroplasty. Further, a peri-prosthetic humeral fracture developed due to a minor trauma. Revision total elbow arthroplasty using a long-stem prosthesis was performed 4 years after the primary total elbow arthroplasty. Radiographs taken 2 years after the revision surgery showed no evidence of implant loosening. In this case, early post-operative loosening occurred despite the use of a linked-type prosthesis and an appropriate cementing technique, suggesting that normal implants may not provide sufficient fixation for neuropathic arthropathy of the elbow. Since surgery for neuropathic arthropathy generally has a poor prognosis, surgical interventions including total elbow arthroplasty should be carefully considered.

Evaluation of Radiographic Changes 5 Years After Arthroscopic Rotator Cuff Repair

Background:

Radiographic changes in the glenohumeral joint often occur after rotator cuff repair; however, the details of the progression and underlying causes remain unknown.

Purpose:

To retrospectively evaluate the timing and frequency of radiographic changes after arthroscopic rotator cuff repair and to clarify the predictive factors that affect the onset of such changes using multivariate analysis.

Study Design:

Case-control study; Level of evidence, 3.

Methods:

We retrospectively reviewed 100 patients with 5 years of follow-up after arthroscopic rotator cuff repair and evaluated the postoperative shift in radiographic findings on plain radiographs every year during follow-up. Factors related to osteoarthritis, acromial spur re-formation, and greater tuberosity resorption at 5 years after surgery were evaluated using logistic regression analyses. Explanatory variables included preoperative factors, intraoperative factors, and postoperative retear. Baseline variables significant in the univariate analyses were included in the multivariate models.

Results:

Of the 100 patients, 12 developed osteoarthritis, 26 developed acromial spur formation, and 16 developed greater tuberosity resorption at 5 years after surgery. The incidence and grade of osteoarthritis and acromial spur gradually increased over time postoperatively. On the other hand, greater tuberosity resorption developed within 2 years after surgery but did not progress later. Multivariate analysis showed that a larger anteroposterior tear size (odds ratio [OR], 1.09; 95% CI, 1.01-1.17; P = .037) was a risk factor for postoperative osteoarthritis. Early retear (OR, 10.26; 95% CI, 1.03-102.40; P = .047) was a risk factor for acromial spur re-formation. Roughness of the greater tuberosity (OR, 9.07; 95% CI, 1.13-72.82; P = .038) and larger number of suture anchors (OR, 3.34; 95% CI, 1.66-6.74; P = .001) were risk factors for greater tuberosity resorption.

Conclusion:

Our study showed that radiographic changes occurred in 40% of patients within 5 years after arthroscopic rotator cuff repair. While the osteoarthritic changes and acromial spur re-formation gradually progressed postoperatively, the greater tuberosity resorption stopped within 2 years after surgery. Tear size, morphology of the greater tuberosity, and the number of suture anchors can affect radiographic changes. Furthermore, this study suggested that acromial spur re-formation may be an indicator of early retears.

Risk factors of radiographic severity of massive rotator cuff tear

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.

A Rare Intra-articular Abnormality in the Posterior Radiocapitellar Joint: A Case Report

Introduction

Posterior radiocapitellar synovial plica excision is sometimes performed for lateral epicondylitis after debridement of the extensor carpi radialis brevis (ECRB) tendon. We describe a rare intra-articular abnormality of the posterior radiocapitellar joint diagnosed on posterior arthroscopic observation.

Case Report

A 48-year-old man presented with posterolateral pain and discomfort in his left elbow. A diagnosis of lateral epicondylitis was made, and arthroscopic debridement of the ECRB tendon was performed. Posterior arthroscopic examination revealed a tendon-like abnormality running longitudinally along the articular surface of the capitulum of the humerus. The abnormality was resected using a shaver, and symptoms improved postoperatively.

Conclusion

In patients with posterolateral pain and discomfort or catching of the elbow, posterior arthroscopic confirmation of the intra-articular structure is recommended after debridement of the ECRB tendon.

Arthroscopic Distal Clavicle Resection for an Acromioclavicular Ganglion Cyst with Cuff Tear Arthropathy: A Case Report

CASE

A 77-year-old man with an acromioclavicular joint ganglion cyst with cuff tear arthropathy had a large mass in the left shoulder. Arthroscopic distal clavicle resection successfully relieved his symptoms without loss of shoulder function by enlargement of the bypass between the cyst and subacromial space through the acromioclavicular joint.

CONCLUSION

Arthroscopic distal clavicle resection can remove a 1-way check valve in a minimally invasive manner. This case indicated that arthroscopic distal clavicle resection could be a useful treatment option for patients with acromioclavicular joint ganglion cysts with functional but irreparable rotator cuff tears.

Bone Block Grafting for Posterior Instability After Anatomical Total Shoulder Arthroplasty: A Case Report

CASE

A 60-year-old woman with avascular necrosis of the right humeral head underwent anatomical total shoulder arthroplasty (TSA); however, recurrent posterior dislocation occurred 13 months postoperatively. We performed bone block grafting of an autologous iliac crest to the posterior glenoid and posterior capsular plication, after which satisfactory postoperative shoulder function without residual joint instability was achieved.

CONCLUSION

The presented case had recurrent posterior dislocation after TSA without any abnormal findings in the prosthetic components. Posterior bone block grafting with capsular plication should be considered a viable option for posterior instability after anatomical TSA.

Blocking screw augmentation in intramedullary nailing for displaced surgical neck fractures of the proximal humerus

A displaced surgical neck fracture can be a good indication for antegrade intramedullary nailing. However, nail insertion may result in malreduction and translational displacement of the humeral head fragment because of muscle traction and size discrepancies between the diameters of the medullary canal and the intramedullary nail. We used blocking screw augmentation in 20 fractures with residual medial displacement of the distal fragment after nail insertion to anatomically reduce displacement of the fracture and to maintain the reduced position before bone union. A blocking screw was placed percutaneously at the lateral side of the canal. Next, a straight intramedullary nail was reinserted medial to the blocking screw. Finally, the nail was locked both proximally and distally. All cases showed bone union without fixation failure at the time of the final follow-up. Blocking screw augmentation with intramedullary nailing is feasible for the treatment of humeral surgical neck fractures and is thought to be helpful for fracture reduction during surgery and stable fixation after surgery.

Risk Factors for Loss of Active Shoulder Range of Motion in Massive Rotator Cuff Tears

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.

Change of wrist motion before and after fixation of the distal radioulnar joint and resection of the distal ulna in a cadaveric model

OBJECTIVE

Recent study suggests the distal radioulnar joint (DRUJ) plays a role in flexion and extension of the wrist. We examined the range of motion (ROM) of the wrist before and after DRUJ fixation and distal ulnar resection in a cadaveric model.

METHODS

Twenty fresh cadaveric human wrists were transected and treated with two sequential interventions: (a) DRUJ fixation, and (b) distal ulnar resection. The angle of maximum flexion and extension of the wrist was measured before and after the procedures. Maximum force to the wrist was determined before the procedures using a digital pressure monitor.

RESULTS

The mean maximum wrist flexion ROM was 84.2° before the procedures. The ROM decreased to 82.5° after DRUJ fixation, and significantly increased to 88.2° after subsequent resection of the distal ulna. The mean maximum wrist extension ROM before the procedures was 73.5°. The ROM decreased to 71.6° after DRUJ fixation, and significantly increased to 77.1° after subsequent resection of the distal ulna.

CONCLUSIONS

Motion of the wrist is affected by DRUJ. This study suggests that the DRUJ might contribute to the ROM in flexion and extension of the wrist.

Total elbow arthroplasty using an augmented reality-assisted surgical technique

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.

Evaluation of Dynamic Carpal Arch Stability following Carpal Tunnel Release Using Four-Dimensional Computed Tomography

Introduction  This study aimed to assess the carpal arch dynamics during active finger and wrist motion following carpal tunnel release using four-dimensional computed tomography (4D-CT). Materials and Methods  Four patients who diagnosed with bilateral carpal tunnel syndrome and underwent unilateral carpal tunnel release were prospectively included. 4D-CT of the bilateral wrists during active finger and wrist motion was performed for 10 seconds at five frames per second. The distances between the tip of tuberosity of the scaphoid and the volar ridge of the pisiform (S-P distance) and volar ridge of trapezium and the tip of hook of hamate (T-H distance) were measured at each position and the values of S-P and T-H distances were compared between the postoperative and contralateral wrists. Results  During finger motion, the S-P and T-H distances were not different at any position between the postoperative side and contralateral side. Conversely, S-P and T-H distances gradually increased in the postoperative wrists. The differences between the sides of S-P distance were significant, with >0 degrees of wrist extension, and differences of T-H distance were significant with >15 degrees of wrist extension. Conclusion  This study demonstrated the carpal arch dynamics using 4D-CT and revealed that the carpal arch was widened with the wrist in extension after carpal tunnel release. This study suggests that the transverse carpal ligament plays an important role in maintaining carpal arch stability.