Huge Distal Ulna Giant Cell Tumor Treated with Wide Local Excision and Extensor Carpi Ulnaris Tenodesis - A Rare Case Report.

Introduction: Giant cell tumors (GCT) are a relatively uncommon type of non-cancerous bone growth, representing around 4-10% of all bone tumors. These tumors tend to exhibit local aggressiveness and are typically prevalent in individuals between 20 and 40 years old. Commonly observed locations for GCT include the distal femur, proximal tibia, and the distal end of the radius. However, occurrences at the distal end of the ulna are rare, accounting for only 0.45-3.2% of cases. Case Report: In this instance, we present the case of a 36-year-old male diagnosed with a GCT specifically located in the left distal ulna. Our approach involved managing the patient through the complete removal (en-bloc resection) of the distal ulna. Following this, we performed an extensor carpi ulnaris (ECU) tenodesis to stabilize the proximal stump. After 2-year follow-up, the patient exhibited positive outcomes, displaying satisfactory wrist joint mobility and functionality without any signs of tumor recurrence. Conclusion: This case emphasizes the effectiveness of wide resection as a viable treatment for huge GCTs in the distal ulna. Utilizing tenodesis with the tendon of ECU significantly contributes to stabilizing the ulnar stump, leading to improved wrist function.

SERCA2a overexpression improves muscle function in a canine Duchenne muscular dystrophy model.

Excessive cytosolic calcium accumulation contributes to muscle degeneration in Duchenne muscular dystrophy (DMD). Sarco/endoplasmic reticulum calcium ATPase (SERCA) is a sarcoplasmic reticulum (SR) calcium pump that actively transports calcium from the cytosol into the SR. We previously showed that adeno-associated virus (AAV)-mediated SERCA2a therapy reduced cytosolic calcium overload and improved muscle and heart function in the murine DMD model. Here, we tested whether AAV SERCA2a therapy could ameliorate muscle disease in the canine DMD model. 7.83 × 1013 vector genome particles of the AAV vector were injected into the extensor carpi ulnaris (ECU) muscles of four juvenile affected dogs. Contralateral ECU muscles received excipient. Three months later, we observed widespread transgene expression and significantly increased SERCA2a levels in the AAV-injected muscles. Treatment improved SR calcium uptake, significantly reduced calpain activity, significantly improved contractile kinetics, and significantly enhanced resistance to eccentric contraction-induced force loss. Nonetheless, muscle histology was not improved. To evaluate the safety of AAV SERCA2a therapy, we delivered the vector to the ECU muscle of adult normal dogs. We achieved strong transgene expression without altering muscle histology and function. Our results suggest that AAV SERCA2a therapy has the potential to improve muscle performance in a dystrophic large mammal.

Chronic Volar Dislocation of the Distal Radioulnar Joint Stabilised by a Partial Extensor Carpi Ulnaris Tendon Strip - A Case Report.

Volar dislocation of the distal radioulnar joint is a rare injury that is often missed at initial presentation. We report a 21-year-old male patient who presented 2 months after sustaining this injury. He was successfully managed by open reduction and reconstruction of the dorsal radioulnar ligament using a partial distally based extensor carpi ulnaris tendon strip. A literature review showed only a few reported cases with varied methods for management. The technique utilised is analysed in comparison to the others. Level of Evidence: Level V (Therapeutic).

The Effect of Arthroscopic Triangular Fibrocartilage Repair on Accompanying Extensor Carpi Ulnaris Tendinitis and Synovitis in Triangular Fibrocartilage Tears.

Purpose Management of ulnar-sided wrist pain is difficult due to the complexity of the anatomy and the similarity of the signs and symptoms of possible diagnoses. The study's main purpose is to examine the effect of arthroscopic triangular fibrocartilage (TFC) repair on untreated extensor carpi ulnaris (ECU) tendinitis and synovitis. Methods Thirteen patients who underwent arthroscopic TFC repair in our clinic and preoperatively demonstrated ECU tendon pathology with magnetic resonance imaging (MRI) were included in the retrospective study. Pre- and postoperative visual analog scale (VAS), pre- and postoperative tendinitis and synovitis, postoperative Mayo and patient-rated wrist evaluation score, postoperative grip strength of the operated and control sides, short and long diameters of the ECU tendon in ultrasonography were recorded. Results The mean age of 13 patients (9 females and 4 males) was 39.54 ± 13.54, and the mean follow-up period was 26 ± 7.25 months. While there was no significant difference between pre- and postoperative tendinitis or synovitis levels, VAS decreased significantly (8.46 ± 1.33 vs. 3.00 ± 2.31, p = 0.0016). While the grip strength was 21.78 ± 7.83 on the control side, it was 18.28 ± 7.51 on the surgery side, being significantly lower ( p = 0.0252). Ulnar variance did not affect tendinitis or synovitis. Short and long diameters of ECU were similar for the operated and control sides. While the short diameter did not affect the synovitis-tendinitis score, the bigger the long diameter, the higher the synovitis score (rho = 0.5162). Conclusion In the presence of ECU, tendon pathologies accompanying TFC lesions, additional surgical interventions are mandatory as arthroscopic TFC repair has no significant effect on the healing of ECU. Level of evidence : 4.

Operative Management of Extensor Carpi Ulnaris Instability: A Systematic Review.

Background Posttraumatic extensor carpi ulnaris (ECU) instability is an increasingly recognized cause of ulnar-sided wrist pain that occurs when the ECU subsheath is disrupted. Purpose The purpose of this systematic review was to assess outcomes of operatively treated posttraumatic ECU instability. Methods A systematic search of Medline, Embase, Web of Science, and CINAHL (Cumulative Index to Nursing and Allied Health Literature) databases was performed using "extensor carpi ulnaris" as the keyword. Studies were systematically screened and data extracted independently by two reviewers. Results Eight retrospective studies met the inclusion criteria with a total of 97 wrists. The mean age was 32 years (13-61). Patients underwent either primary repair (40%) using sutures and anchors, or reconstruction (60%) using extensor retinaculum flaps. One study performed deepening of the osseous ulnar groove. Two studies compared preoperative and postoperative values. They both reported a significant improvement in pain scores, functional scoring instruments, satisfaction, and grip strength. The rest of the studies reported similarly favorable outcomes across the same outcomes. Concomitant pathologies were identified in 66% of the study population. Complications occurred in 9% of the sample size, including ECU tendinitis, ulnar sensory nerve irritation, and reintervention for concomitant pathology. None of the studies reported recurrence or reruptures. However, five patients (6.7%) did not return to their previous activity level. Conclusion Patients can expect favorable outcomes with a potentially low complication rate. Nevertheless, the heterogeneity of the sample population, operative techniques, and outcome measures warrant further standardized studies. Level of Evidence IV.

A Novel Technique Using the Dorsal Capsule of the Distal Radioulnar Joint for Extensor Carpi Ulnaris Tendon Subsheath Reconstruction.

Background Ulnar-sided wrist pain is a common problem encountered by hand surgeons. Symptomatic recurrent subluxation of the extensor carpi ulnaris (ECU) tendon has become increasingly recognized as one of the pathological conditions leading to ulnar-sided wrist pain. Surgical reconstruction of the subsheath is usually needed. ECU tendon subsheath reconstruction with the periosteal flap was first described by Schlesinger in 1907. Since then, various other techniques have been widely used. We describe a technique of ECU subsheath reconstruction using the dorsal capsule of the distal radioulnar joint (DRUJ). Description of Technique Two hand surgeons performed the surgeries with the same steps taken each time. A detailed description of our surgical technique, with the dorsal capsule of the DRUJ used to reconstruct the ECU tendon subsheath, is illustrated. Patient and Methods Patients who presented with symptomatic ECU instability despite conservative treatment or who have failed primary subsheath repair were offered this surgical option. Patients were followed up postoperatively for an average duration of 6.7 months in our outpatient clinics for assessment of wrist function. The surgical outcomes were reviewed and graded with the Modified Mayo Wrist Score (MMWS). Results All but one of the seven patients had an overall improvement in their range of movement of the wrist, grip strength, and pain scores. Four patients had excellent outcomes on the MMWS, one of whom had an asymptomatic recurrence seen on dynamic ultrasound. Two patients required subsequent surgeries: one had an excellent outcome and the other had a poor outcome on the MMWS. Conclusion We present our first seven cases of ECU subsheath reconstruction with the dorsal capsule of the DRUJ. Our results in the short term have been satisfactory. The technique does not disrupt the integrity of the extensor retinaculum, which is essential for optimal extensor tendon function, and can also be considered as an option to salvage failed procedures.

Bilateral Avulsion Fractures of Extensor Carpi Ulnaris: A Case Report.

Introduction: Avulsion fractures of the extensor carpi ulnaris (ECU) from its insertion are rare injuries that are rarely reported in the literature. Most of the case reports detailed closed ruptures. We present avulsion fractures of the bilateral ECU from the base of the 5th metacarpal. Not much of the literature has been published in this regard. Case Report: A 33 year old male presented with pain around both wrists and hands following a fall from a bike. Following evaluation and radiological investigation, he was found to have a volar Barton fracture with an undisplaced avulsed 5th metacarpal base fracture on the right side and a displaced avulsed fracture of the left 5th metacarpal base. Internal fixation of the volar Barton fracture and mini open fixation of the left 5th metacarpal were done with a wire. The wires were removed at 6 weeks and rehabilitation started. At 3 months, the patient returned to activity with full wrist and hand function. Conclusion: Bilateral avulsion fractures of the ECU from its insertion are a rare injury. Displaced fractures might benefit from surgical intervention. Early diagnosis and treatment are essential for a good functional outcome.

An alternative treatment for degenerative triangular fibrocartilage complex injuries with distal radioulnar joint instability: first experience with 48 patients.

Treatment of ulnar impaction syndrome combined with distal radioulnar joint instability due to irreparable degenerative triangular fibrocartilage complex injuries can be complex. We describe the outcomes of a novel technique for restoring distal radioulnar stability due to ulnar impaction syndrome using a distally based extensor carpi ulnaris tendon strip combined with ulnar shortening osteotomy in 48 patients. Patients were assessed using standardized outcome measurements. The patient-rated wrist/hand evaluation total score improved from 66 (SD 15) at intake to 40 (SD 25) at 3 months, and 28 (SD 23) at 12 months postoperatively (p < 0.001). Wrist extension and flexion improved significantly at 12 months from 53° (SD 11) to 65° (SD 8) (p < 0.001) and from 45° (SD 10) to 56° (SD 12) (p = 0.01), respectively. Adding a distally based longitudinal extensor carpi ulnaris strip to ulnar shortening osteotomy for restoring distal radioulnar joint stability seems to be an effective treatment in patients with irreparable degenerative triangular fibrocartilage complex injuries due to ulnar impaction syndrome. Level of evidence: IV.

Giant cell tumors of the distal ulna: long-term recurrence rate and functional outcomes of en bloc resection versus curettage in a multicenter study.

OBJECTIVE: The wrist is the second most commonly involved location for GCTB, while distal ulna is a relatively rare location and limited evidence exists on which surgical approaches and reconstruction techniques are optimal. We carried out a multicenter retrospective study to evaluate the recurrence rate of distal ulna GCTB and the long-term functional outcomes of different surgery options. METHODS: All 28 patients received surgical treatment for distal ulna GCTB in one of three tertiary bone tumor centers between May 2007 and January 2021 with a minimum two-year follow-up. Surgical options included intralesional curettage or en bloc resection (one of 3 types). Functional outcomes were assessed by the MSTS score, the QuickDASH instrument, MWS, and MHQ according to the latest treatment. RESULTS: Overall recurrence rate was 14.2%. The curettage group (N = 7) had a significantly higher recurrence rate compared to en bloc resection (N = 21) (42.9% vs 4.8%) (mean follow-up: 88.8 mo). Seven patients received the Darrach procedure, 5 received the original Sauvé-Kapandji procedure, and 9 received the modified Sauvé-Kapandji procedure with extensor carpi ulnaris (ECU) tenodesis. Of the 4 patients having a recurrence, 1 received the Darrach EBR, 2 received the modified Sauvé-Kapandji procedure, and 1 received resection for soft tissue recurrence. Only MWS and esthetics in the MHQ scores were different (curettage, Darrach, Sauvé-Kapandji, and Sauvé-Kapandji with ECU tenodesis [MWS: 96.5 ± 1.3 vs 91.5 ± 4.7 vs 90.8 ± 2.8 vs 91.5 ± 3.6; esthetics in MHQ: 98.5 ± 3.1 vs 89.9 ± 4.7 vs 93.8 ± 4.4 vs 92.6 ± 3.8], respectively). CONCLUSIONS: En bloc resection for distal ulna GCTB had a significantly lower recurrence rate compared with curettage and achieved favorable functional outcome scores. Given the higher recurrence rate after curettage, patients should be well informed of the potential benefits and risks of selecting the distal radioulnar joint-preserving procedure. Moreover, reconstructions after tumor resection of the ulna head do not appear to be necessary.

The Surgical Treatment of Bilateral Accessory Extensor Carpi Ulnaris: Case Report and Literature Review.

Several abnormal pathologies, such as inflammation or degenerative change, can be causes of ulnar-sided wrist pain. This study demonstrated bilateral accessory extensor carpi ulnaris found in a patient who presented with bilateral wrist pain. The patient was initially treated with all conventional methods but failed to improve. Following the operation by releasing the sixth extensor compartment, the pain was completely relieved. The Disabilities of the Arm, Shoulder, and Hand (DASH) score was remarkably improved and there was no limitation in daily living activities compared with preoperative status. We presented an uncommon condition of ulnar-sided wrist pain caused by bilateral accessory extensor carpi ulnaris which was successfully treated by releasing the extensor compartmental sheath without tendon resection.

Extensor Carpi Ulnaris Instability: A Comprehensive Review of Pathology and Operative Techniques.

The extensor carpi ulnaris (ECU) is primarily responsible for extension and ulnar deviation at the wrist. Secondary to repetitive loading of, or acute trauma to the flexed, supinated and ulnarly deviated wrist, the ECU tendon can be a common source of ulnar-sided wrist pain. Common pathology includes ECU tendinopathy, tenosynovitis, tendon instability, and tendon rupture. Extensor carpi ulnaris pathology commonly occurs in athletes and patients with inflammatory arthritis. Given the multitude of available methods to treat ECU tendon pathology, the aim of our study was to outline operative management of ECU tendon pathology, with emphasis on reviewing techniques for addressing ECU instability. We acknowledge a continuing debate between anatomical and nonanatomical techniques for ECU subsheath reconstruction. However, use of a portion of the extensor retinaculum for nonanatomical reconstruction is commonly used and demonstrates successful outcomes. Future comparative studies on ECU fixation are required to increase data on patient outcomes, to further define and standardize these techniques.

Isolated Avulsion Fracture of the Extensor Carpi Ulnaris: A Case Report and Review of Literature.

Avulsion fractures of the extensor carpi ulnaris (ECU) insertion are rare injuries that are poorly described in the literature. Several case reports detail closed ECU ruptures, however, only one previous case report describes an ECU avulsion fracture from the insertion on the fifth metacarpal base in the setting of multiple wrist and hand injuries. To our knowledge, we present the only case report of an isolated ECU avulsion fracture. In our case, a 35-year-old female presented with ulnar-sided wrist pain after forcefully impacting a steering wheel while radially deviating her wrist. She was diagnosed with an ECU avulsion fracture and elected to undergo open repair with a suture button technique. The patient recovered to nearly full strength and range of motion compared to her contralateral side by her eight-week visit. She returned back to work without restrictions after completing hand therapy.

A Central Slip Injury in a Professional Basketball Player.

Hand injuries are extremely prevalent in sports such as ball sports. Delayed diagnosis or improperly managed injuries have the potential to prolong the athlete's return to the competition and permanently damage their abilities. We report the case of a 35-year-old male professional basketball player who presented to a chiropractor with pain and swelling of the right fifth finger two days after a basketball game. The injury occurred when a player passed the basketball and the ball hit his fifth finger "head-on". Examination revealed enlargement of the middle joint of the right fifth finger and a boutonniere deformity. He was diagnosed with a central slip injury using magnetic resonance imaging (MRI). Since there are no standard treatment guidelines for central slip injuries, multi-model chiropractic therapy was applied to the injury and adjacent sites. The patient returned to the game by the end of the third week and fully recovered within six weeks. Chiropractors must understand how to best guide athletes' clinical management of these injuries, given the inherent need for immediate and complete recovery.

Radially Based Extensor Retinacular Sling Reconstruction for Extensor Carpi Ulnaris Subsheath Injuries in Elite Athletes.

BACKGROUND: Extensor carpi ulnaris (ECU) subsheath injuries are an increasingly recognized cause of ulnar-sided wrist pain in elite athletes. There is a lack of surgical outcome data in elite athletes, and unique considerations exist for these patients. METHODS: We performed a retrospective review of our hand center experience of 14 elite professional or collegiate athletes who prospectively underwent radially based extensor retinacular sling ECU subsheath reconstruction by 3 hand surgery-fellowship-trained surgeons between April 2011 and April 2021. Clinical, magnetic resonance imaging (MRI), and intraoperative findings were cataloged. Subgroup analyses of elite hockey players and acute subsheath injuries were also conducted. Statistical analysis was performed via a 2-tailed paired t test. RESULTS: Mean age at the time of surgery was 21.3 years (range, 18-34). Mean time from symptom onset to surgery was 102.1 ± 110.7 days. All 14 patients underwent preoperative MRI. Five patients (35.7%) had intrinsic ECU tendinopathy, 9 patients (64.3%) had ECU tenosynovitis, 6 patients (42.9%) had triangular fibrocartilage complex tears, and 9 patients (64.3%) had ulnocarpal synovitis. Mean postoperative pain on a Visual Analog Scale was 0.25 ± 0.43. Grip strength (P = .001), wrist flexion-extension (P = .037), and pronosupination arcs (P = .093) showed excellent recovery postoperatively. Mean time to unrestricted return to sports was 92.5 ± 21.0 days. There were no complications. Subgroup analyses found similar functional improvement and characterized injury patterns. CONCLUSIONS: Overall, our findings suggest surgical management of ECU subsheath injuries is a viable option in both acute and chronic settings in elite athletes and may be favorable compared with nonoperative management.

Motion Analysis of the Extensor Carpi Ulnaris in Triangular Fibrocartilage Complex Injury Using Ultrasonography Images.

The subsheath of the extensor carpi ulnaris (ECU) tendon, a component of the triangular fibrocartilage complex (TFCC), is particularly important as it dynamically stabilizes the distal radioulnar joint. However, the relationship between TFCC injury and ECU dynamics remains unclear. This study aimed to analyze ECU movement and morphology using ultrasonography (US) images. Twenty wrists of patients with TFCC injury, who underwent TFCC repair, were included in the injury group, and 20 wrists of healthy volunteers were in the control group. For static image analysis, curvature and linearity ratios of the ECU in US long-axis images captured during radioulnar deviation were analyzed. For dynamic analysis of the ECU, the wrist was moved from radial deviation to ulnar deviation at a constant speed, and the velocity of the tendon was analyzed using particle image velocimetry. The static analysis showed that the ECU tendon was more curved in ulnar deviation in the injury group than in the control group, and the dynamic analysis showed that only vertical velocity toward the deep side during ulnar deviation was higher in the injury group. These results suggest that TFCC injury caused ECU curvature during ulnar deviation and increased the vertical velocity of the ECU during wrist deviation.

Treatment of subacute/chronic ECU tendinopathy using wrist arthroscopy and open surgical repair.

PURPOSE: To report the arthroscopic and clinical findings of patients with extensor carpi ulnaris (ECU) tendinopathy treated with wrist arthroscopy and open surgical repair. METHODS: We retrospectively reviewed the medical records of seven patients with chronic ECU tendinopathy who were treated with diagnostic wrist arthroscopy and open surgical repair between 2010 and 2017. Seven cases diagnosed with ECU tendinopathy had undergone open procedure for the ECU tendinopathy, as well as wrist arthroscopy in the same session. Any pathology of the triangular fibrocartilage complex (TFCC) diagnosed by wrist arthroscopy were treated simultaneously with open procedure for the ECU tendinopathy. The functional outcome was evaluated by comparing the preoperative and final follow-up values of range of motion (ROM), grip strength, visual analog scale (VAS) for pain, modified Mayo wrist score and quick disabilities of the arm, shoulder, and hand (DASH) score. RESULTS: TFCC tears were identified in four patients of which repair was performed concomitantly. The average follow-up period was 39 months (range, 25-49 months). At the final follow-up, all the outcomes including average VAS score (6.4→1), the ROM (173→192°), quick DASH score (42.5→18.2), and modified Mayo wrist score (48.6→79.3) improved significantly. CONCLUSION: When treating patients with ECU tendinopathy, the possibility of TFCC combined injury should always be considered. If surgical treatment is planned, we suggest a wrist arthroscopy for more accurate diagnosis an intra-articular pathology, particularly for patients whose MRI findings suggest a degenerative tear or degeneration at the periphery of the TFCC. Additionally, if ECU and DRUJ stability is obtained by repair or reconstruction of the concurrent pathologies in the ECU subsheath, TFCC and other intra-articular structures, the results will be favorable.

Do "Anatomic" Distal Ulna Plating Systems Fit the Distal Ulna Without Causing Soft Tissue Impingement?

Background: Distal ulna fracture fixation plates commonly cause irritation, necessitating removal, due to the narrow area between the ulna articular cartilage and the extensor carpi ulnaris. This study defines the safe zone for plate application and determines whether wrist position affects risk of impingement. Methods: Four different distal ulna anatomic plates (Acumed, Medartis, Skeletal Dynamics, and Synthes) were applied to 12 cadaveric specimens. Safe zone size was measured in circumferential distance and angular arc. Impingement was examined in flexion and extension in neutral, pronation, and supination. Results: The distal ulna safe zone has dimensions of a 92° arc and perimeter circumference of 15 mm. Cumulative extensor carpi ulnaris (ECU) impingement occurred in 0% of the 6 simulated wrist/forearm positions for the Acumed plate, 22% for the Synthes plate, 31% for the Skeletal Dynamics plate, and 68% for the Medartis plate. Impingement was most common in supination. Likelihood of ECU impingement significantly decreased in the following order; Medartis > Skeletal Dynamics > Synthes > Acumed. Conclusion: The ECU tendon's mobility can cause impingement on ulnarly placed distal ulna plates. Intra-operative testing should be performed in supination. Take home points regarding each plate from the 4 different manufacturers: contouring of Medartis plates, when placed ulnarly, is mandatory. The Acumed plate impinged the least but is not designed for far-distal fractures. The Synthes plate is least bulky but not suitable for proximal fractures. The Skeletal Dynamics plate appeared the most versatile with a reduced incidence of impingement compared to other ulnarly based plates.

A Simplified Modification of the Henderson Extensor Carpi Ulnaris Opposition Transfer.

PURPOSE: There are several potential donor muscle-tendon units for a thumb opposition transfer. The extensor carpi ulnaris (ECU) is useful when the more usual donor units are not available. The technique and results of a simplified ECU opposition transfer elongated with a free tendon graft are described. METHODS: Ten ECU opposition transfers were performed using this modification of Henderson technique in 5 adults after complex trauma, 3 adults with median and ulnar nerve palsies, and 2 children with congenital hand differences. RESULTS: Seven patients achieved a Kapandji opposition score of 6 to the distal phalanx of the small finger, and 3 patients achieved a Kapandji score of 5 to the distal phalanx of the ring finger. None of the patients required a secondary tenolysis or developed a radial deviation imbalance of their wrist. CONCLUSIONS: This modification of the Henderson technique using ECU elongated with a free tendon graft and inserted directly and only into the abductor pollicis brevis tendon is an effective method of restoring opposition to the thumb, especially when other conventional donor muscle-tendon units are not available. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic V.

"Snapping" of the extensor carpi ulnaris tendon in asymptomatic population.

BACKGROUND: Extensor carpi ulnaris tendinopathy (ECU) can be one cause of ulnar side wrist pain and it is more prominent in pronation-supination movements against resistance. In supination, flexion, and ulnar deviation within the ulnar groove, the tendon is tense and becomes predisposed to subluxation or dislocation. Snapping occurs during this dislocation and relocation. As a result of this friction between the tendon sheath and ulnar groove, tendinopathy and pain occur. ECU tendon is an important structure that contributes to the dynamic stability of wrist therefore resulting degeneration contributes disruption of distal radioulnar joint and causes wrist instability. METHODS: Participants without active wrist complaints who presented to the outpatient clinic between 2019 and 2020 were included. Provocation test was performed and participants with snapping were evaluated with ultrasound to determine subluxation or dislocation. Participants asked to indicate approximately how much time they spent daily on the phone, computer and game console. The distribution of data was evaluated with the Kolmogorov-Smirnov test. Quantitative data that were not normally distributed were evaluated using the Mann-Whitney U test, and Student's t-test was used for normally distributed data. The Chi-square test was used to compare categorical variables. For all tests, p < 0.05 was considered statistically significant. RESULTS: Four hundred and fifteen women and 340 men were included in the study. Fifty of the 755 participants (6.6 %) had snapping. 22 of the 755 participants (2.9 %) had dislocation or subluxation on ultrasound. Three (13.6 %) participants had dislocation and 19 (%86.4) participants had subluxation on ultrasound. All 50 of the participants with snapping had significant repetitive trauma and sports activities. It was determined that 21 of the 22 participants who were found to have subluxation or dislocation by ultrasound had more than two hours of hobby activity and significantly more participants had more than two hours of activity compared to the group without subluxation or dislocation. CONCLUSIONS: This study with a large number of participants will contribute to the literature in terms of evaluating the contribution of technological devices, such as computers, smartphones, and consoles to chronic wrist pain and the prevalence of ECU snapping in the asymptomatic population. TRIAL REGISTRATION: Date of Approval; 19.02.2019, Approval Number; 19-KAEK-045.

Anatomical Study of Stabilizing Structures of the Extensor Carpi Ulnaris Tendon Around the Wrist.

PURPOSE: The sixth dorsal extensor compartment is a relatively common site of stenosing tenosynovitis in the upper extremity, but the exact location of stenosis is not fully understood. The objective of this study was to investigate the detailed anatomy of structures surrounding the extensor carpi ulnaris (ECU) tendon around the wrist. METHODS: Fifty fresh human cadaveric wrists were used for gross observation and morphology measurements of the sixth dorsal compartment and the ECU subsheath. An additional 13 wrists were used for histological examination. We evaluated the morphology of supporting structures in 3 regions: the ulnar groove (zone I), the ulnar styloid process (zone II), and the triquetrum (zone III). RESULTS: The fibro-osseous tunnel comprising the ulnar groove and the overlying subsheath (zone I) stabilized the ECU tendon, and the subsheath had thin membranous collagen fibers attached to the periosteum. We consistently found the distal extension of ECU subsheath (zone II), which connected the ulnar styloid process and the dorsal radioulnar ligament. Variations in the length of the distal extension increased with the forearm in pronation. Collagen fiber thickness around the ECU tendon in zone II was greater than that of zone I. In zone III, the overlying extensor retinaculum and septa, which were composed of thick circumferential collagen structures, supported the ECU tendon by attaching to the triquetrum on both sides of the ECU tendon. We found the presence of an ulnar septum of the sixth compartment attached to the triquetrum in 84% of dissected wrists. CONCLUSIONS: The ECU tendon was supported by the ECU subsheath, which had thin and elastic collagen fibers over the ulnar groove. Distal extension of the subsheath and surrounding radial and ulnar extensor retinaculum septa attached to the triquetrum provided thicker supporting structures. CLINICAL RELEVANCE: Stenosing ECU tenosynovitis may occur not only in the ulnar groove but also in the more distal ulnar styloid process and triquetrum areas.