Extensor Pollicis Brevis Tendon Research Articles

Relationship to the superficial radial nerve and anatomic variations of the first extensor compartment in Thai population: a basis for successful de Quervain tenosynovitis treatment.

Knowledge of the superficial radial nerve (SRN) relationship and anatomic variations of the first extensor compartment (1st EC) will contribute to a better outcome of de Quervain tenosynovitis treatment. We dissected 87 embalmed cadaveric wrists to determine the relationship of the SRN, the 1st EC length, distance from the proximal and distal 1st EC borders to radial styloid process (RSP), abductor pollicis longus (APL) and extensor pollicis brevis (EPB) tendon slip numbers, and the presence of septum. Our results revealed SRN crossing over the 1st EC in 59.5%. The lateral branch of the superficial radial nerve to the 1st EC midline in most cases (61.9%) except for one specimen, where lateral antebrachial cutaneous nerve was the closest. Distances from proximal and distal 1st EC borders to the RSP were 19.7±4.1 mm and 7.6±1.8 mm, respectively. Extensor retinaculum (ER) width over 1st EC (1st EC length) was 14.8±3.2 mm. Complete and incomplete septa were found in 17.2%, and 42.5%, respectively. The most frequent APL tendon slip number in the compartment was two in overall 47 specimens (54.0%). Almost all compartments (85 specimens; 97.7%) contained one EPB tendon slip. We detected bilateral EPB absence in one cadaver. Moreover, we recorded a tendon slip from extensor pollicis longus traveling into 1st EC bilaterally in one cadaver and observed the EPB muscle belly extension into 1st EC in 9 wrists. Awareness of 1st EC anatomic variations would be essential for successful surgical and nonsurgical outcomes.

De Quervain tendinitis after total trapeziometacarpal joint arthroplasty: Biomechanical evaluation of tendon excursion in the first extensor tendon compartment

De Quervain’s tenosynovitis is the most common complication after total trapeziometacarpal joint replacement. Etiology is unclear. Implantation of a ball-in-socket implant changes the biomechanics of the normal trapeziometacarpal saddle joint and increases its range of motion. The present study demonstrates that this procedure also significantly increases excursion of the abductor pollicis longus and extensor pollicis brevis tendons during thumb flexion-extension, and not during thumb abduction-adduction. Increased tendon gliding under the retinaculum of the first extensor tendon compartment could predispose to the development frictional tenosynovitis and play a role in the development of de Quervain’s syndrome after total trapeziometacarpal joint replacement. Level of evidenceNot applicable (laboratory study).

The place of B-mode ultrasonography, shear-wave elastography, and superb microvascular imaging in the diagnosis of De Quervain tenosynovitis.

Superb microvascular imaging (SMI) and Shear wave elastography (SWE) are newly developed ultrasonographic diagnostic tools used to support the diagnosis of De Quervain tenosynovitis (DQT). The aim of this study was to examine the capacity to differentiate between the wrist with DQT and the healthy wrist, as well as the potential for predicting the disease's severity using B-mode ultrasonography, SWE, and SMI. A total of 19 cases with unilateral clinical DQT were included in the prospective study. The wrists of these cases without DQT clinic constituted the control group. The SWE parameters of m/s and kPa cutoff values were ≤5.225 and ≤ 77.65, respectively, in the wrists with DQT compared to the wrists not diagnosed with DQT (p < 0.001). Regarding SMI findings no microvascularity was determined in the abductor pollicis longus (APL) and extensor pollicis brevis (EPB) tendon sheaths of the wrists without DQT, and a significant increase was observed in the degree of microvascularity as the clinical severity of DQT increased. SWE results can differentiate between the presence and absence of DQT. SMI grading of the APL and EPB tendon sheaths may be helpful to the clinician in deciding the clinical severity of DQT.

Opposition Transfer Using the Extensor Indicis Muscle and the Extensor Pollicis Brevis Tendon

PurposeThis study aimed to introduce a novel technique utilizing the extensor pollicis brevis and extensor indicis proprius tendons as power sources for thumb opposition reconstruction in cases of severe carpal tunnel syndrome (CTS) associated with thenar muscle atrophy. Further, the efficacy of this novel method and the traditional Camitz technique was compared. MethodsPatients with severe CTS and thumb opposition dysfunction who underwent surgery using the novel technique (n = 7, 9 surgeries) or the Camitz technique (n = 8, 8 surgeries) were included in the analysis. The pre- and postoperative palmar abduction angle, thumb–ring finger opposition (T–R) angle, and Kapandji score were assessed. The repeated measures ANOVA and the Mann–Whitney U test were used for statistical analysis. ResultsThe novel technique was associated with a significant postoperative improvement in palmar abduction angle, T–R angle, and Kapandji score. In particular, the T–R angle of patients who underwent surgery using this technique was superior to that of patients who underwent surgery using the Camitz technique. Therefore, the novel technique was highly effective in improving thumb pronation. ConclusionThe novel technique using the extensor pollicis brevis and extensor indicis proprius tendons is promising for thumb opposition reconstruction in severe CTS cases. Unlike the traditional Camitz technique, this approach promotes stable thumb opposition function without requiring a pulley, thereby yielding satisfactory outcomes. Nevertheless, further studies with a larger sample size should be conducted to validate these findings.

How to Omit the Potential Pitfalls in Distal Radial Access: Lessons From Cadaveric and CTA Analysis.

To verify the anatomical basis, ideal puncture sites, and potential pitfalls of the distal radial artery (dRA) in the anatomical snuffbox region for distal radial access (dTRA). Overall, 26 formalin-fixed upper limbs and computed tomography angiography (CTA) of the upper limbs of 168 consecutive patients were studied. Cadaveric dissection and dRA 3D reconstruction were used to evaluate the dRA route for dTRA. The puncture sites, dRA diameter, and angle of the dRA and tendons of the extensor pollicis brevis were also measured in the patients and cadavers. The cadaver dissection provided more insights than did the dRA 3D reconstruction. However, preoperative evaluation had better diagnostic accuracy (p=0.024). Puncture sites 1 and 3 had a high success rate (63.2% possible success rate, 191/302). The DISFAVOR theory was put forward, in which 8 types of potential pitfalls that may interrupt puncture procedure or lead to a surgical failure were observed, including occlusion, stenosis, tortuosity, arteriovenous fistula, angioma, different radial artery (RA) ramifications, radial veins, and cephalic veins. The mean diameter of dRA based on cadaver dissection and CTA was 2.53 (SD=0.73) and 2.63 (SD=0.69) mm, respectively. Furthermore, the minimum distance from the outer layer of dRA to the skin was 5.71 (SD=2.0) mm based on CTA. The angle between the dRA and tendons of extensor pollicis brevis (TEPB) based on cadaver dissection and CTA was 58.0° (SD=21.5°) and 51.8° (SD=16.6°), respectively. Puncture sites 1 and 3 were more suitable for the dTRA, and we put forward the DISFAVOR theory to summarize the 8 types of potential pitfalls during the use of dTRA.

Insights with consensus on Abductor Pollicis Longus from the Central Indian population at Nagpur, Maharashtra.

The anatomical snuff box is bounded laterally by the Abductor pollicis longus (APL) and the Extensor pollicis brevis (EPB) tendons. The variation in insertion of extensor tendons at the forearm and wrist is an interesting phenomenon. Therefore, a sound knowledge of such variations in extensor tendons is essential to know the consequence of tendon injury during implementation of its repair. Hence, we studied 48 formaldehyde fixed forearms of Indian-origin cadavers with age groups ranging from 33 to 67 years from the Central Indian population at Nagpur, Maharashtra, India. Variation in the insertion of APL was checked by tracing the tendon till its insertion. APL muscle was found with single tendon in 20 forearms, double in 9, triple in 8 and quadruple in 5 and five (maximum) in 6 forearms. In 93% (n=45), the APL tendon was inserted into the first metacarpal bone and in 7% (n=03), it was inserted into the trapezium bone. No variation was noted in the EPB tendon. Data shows that there are accessory slips in the APL tendon, differing from the standard description. Thus, data provides awareness of such potential variation among operating surgeons for better management of the diseased during dissection.

Anatomical variations in the first dorsal compartment of the wrist: meta-analysis.

The first dorsal compartment of the wrist includes tendons of abductor pollicis longus (APL) and extensor pollicis brevis (EPB). However, many studies have showed multiple anatomical variations including anomalies in the number of both APL and EPB tendons and presence of intercompartmental fibro-osseous septum. Unfortunately, studies describing those variations are not consistent, hence, the aim of this study was to provide most accurate data about these anatomical variations in the population, using systematic review and meta-analysis. For this purpose, PubMed, Scopus, Web of Science, Embase and a number of minor online libraries were searched. Articles which included exact data about the number of APL or EPB tendons or a presence of intercompartmental septum were qualified for a more precise evaluation. Therefore, out of 1629 studies initially evaluated, 68 were finally included in this meta-analysis. We followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. A total of 5229 studied wrists have been included in this study. Double APL and single EPB are the most common variations of tendons in the first dorsal compartment, both in cadavers and patients with de Quervain's disease, with no statistically significant differences between those two groups. Presence of intercompartmental fibro-osseus septum is much more common in patients with de Quervain's disease than in cadavers. Our results should improve the awareness of anatomical variations in the first dorsal compartment, which in turn should have impact on treatment of de Quervain's disease in clinical practice.

Work-Related Risk Factors Contributing to De-Quervain's Tenosynovitis among Carpenters in Punjab

Purpose: De Quervain's Tenosynovitis is inflammation of extensor pollicis brevis and abductor pollicis longus tendons that run from the side of the wrist to the base of the thumb. To see the frequency of De Quervain’s Tenosynovitis and work related risk factors in carpenters of Punjab, Pakistan&#x0D; Methodology: It was a cross-sectional study. Sample size of the research was 492. Study was conducted at the province Punjab, Pakistan. Inclusion criteria of the study were carpenters of age between twenty to fifty years having experience of more than 2 years. Data was collected to the selected population, through convenient sampling technique. Duration of the study was 8 months. Outcome measures of the study were Finkelstein test, Visual analogue scale and a structured questionnaire. The collected data was analyzed by using SPSS version 25.&#x0D; Findings: Out of 492 participants, De-Quervain's Tenosynovitis was found to be present in 46% of carpenters Punjab. 25.6% of the participants had moderate, while 22.3% had extreme discomfort in lower back. 19.91% reported not to have an enough space for work. 55.69% didn’t take adequate breaks while working. 69.91% reported to have no back rest while working, 63% reported not use any wrist support or brace while working and 35.36% reported not to have any proper training for this work.&#x0D; Conclusion: De Quervain’s Tenosynovitis is prevalent in carpenters of Punjab, Pakistan. Work-related discomfort was found in various regions of body including eyes, neck, shoulders, arms, wrist and hand. Contributing work-related risk factors for De Quervain's Tenosynovitis among carpenters encompass insufficient training, absence of wrist support, and inadequate breaks during work.

Prevalence of De-Quervain’s Tenosynovitis in Female Tailors in District Wazirabad

Purpose: De Quervain's tenosynovitis affects the thumb abductors close to the radiostyloid process, causes a painful wrist complaint. When performing particular jobs incorrectly, the wrist and thumb might lead to De Quervain's Tenosynovitis. It is associated with work that necessitates repetitive wrist and thumb motion. Pain, numbness, tingling, burning, stiffness, and exhaustion are a few of the warning signs and symptoms. Complaints include a loss of normal sensation, a restriction in range of motion, and a decline in grip strength. The objective of the study was to determine the prevalence of De-Quervain's Tenosynovitis in female tailors in district Wazirabad.&#x0D; Methodology: Amongst female tailors, a cross-sectional survey was done. Based on the inclusion and exclusion criteria, 289 participants were chosen through convenient sampling technique. The process was described to the study participants. The degree of the pain was evaluated using the Numeric Pain Rating Scale (NPRS), and an assessment of the illness was made using the Finkelstein test. Both hands were put to use for the test. Pain over the abductor pollicis longus and extensor pollicis brevis tendons at the wrist is a sign of a positive diagnosis. The SPSS program was used to examine the data. Data was presented in for of tables and charts.&#x0D; Findings: De-Quervain's Tenosynovitis was present in 43% of the population overall. When the results of the right and left hands were compared, it was discovered that 33% females had right hand had De Quervain's tenosynovitis and 10% had it in both hands. Sixty of the respondents reported experiencing mild pain, 41 women reported moderate pain, and 23 reported severe pain. This study concluded that the prevalence of De-Quervain’s Tenosynovitis in female tailors is low.&#x0D; Recommendations: The study was grounded in the Cumulative Stress Theory, emphasizing repetitive motion's impact on occupational health. Tailors should receive training on ergonomics, use ergonomic tools, and undergo regular wrist health check-ups. Policy makers must set occupational health standards for tailors, ensuring ergonomic tool usage, and mandate periodic health audits in tailoring establishments

Prevalence of De-Quervain’s Tenosynovitis in Tailors of Multan (Punjab)

Purpose: De Quervain's Tenosynovitis is inflammation of extensor pollicis brevis and abductor pollicis longus tendons that run from the side of the wrist to the base of the thumb. To see the frequency of De Quervain’s Tenosynovitis and work related risk factors in tailors of Multan, Pakistan&#x0D; Methodology: It was a cross-sectional study. Sample size of the research was 246. Study was conducted at the city of Pakistan, Multan. Inclusion criteria of the study were tailors of age between twenty to fifty years having experience of more than 3 years. Data was collected to the selected population, through convenient sampling technique. Duration of the study was 8 months. Outcome measures of the study were Finkelstein test, Visual analogue scale and a structured questionnaire. The collected data was analyzed by using SPSS version 25.&#x0D; Findings: Out of 246 participants, 72.3% were males and 27.6% were females. Prevalence of De Quervain's Tenosynovitis was found to be 64% in tailors of Multan through Finkelstein test. 25.6% of the participants had moderate, while 22.3% had extreme discomfort in lower back. 35.3% reported to have mild discomfort in arms. 52.4% had mild to moderate discomfort in wrist or hand. 19.91% reported not to have an enough space for work. 44.30% did not have adjustable chairs. 69.91% reported to have no back rest while sewing, 63% reported unavailability of foot rest and 64.63% had no arm rest while sewing.&#x0D; Recommendations: De Quervain’s Tenosynovitis is prevalent in tailors of Multan, Pakistan. Work-related discomfort was found in various regions of body including eyes, neck, shoulders, arms, wrist and hand. Chairs with no adjustable height, unavailability of arm and foot rest and no back support were associated work related risk factors in tailors.

Opponensplasty for Severe Carpal Tunnel Syndrome with the Transfer of the Palmaris Longus Tendon to the Rerouted Extensor Pollicis Brevis Tendon.

The authors describe a novel opponensplasty for severe carpal tunnel syndrome that uses the palmaris longus (PL) tendon transferred to the rerouted extensor pollicis brevis (EPB) tendon with pulley reconstruction using a portion of the PL tendon simultaneously with the carpal tunnel release. Like the Camitz opponensplasty, this technique utilises the PL as the motor source, does not require special postoperative treatment and enables fast functional recovery even in older patients. Compared with the Camitz procedure, this technique can easily acquire thumb rotation without tendon bowstringing. Furthermore, because the function of the EPB tendon is preserved, the tendency of flexion in the thumb metacarpophalangeal (MP) joint is not observed after surgery, and improvement can be expected in patients with preoperative MP joint extension lag. This technique is a useful alternative to the Camitz procedure, as it overcomes the disadvantages of the Camitz procedure while preserving the advantages. Level of Evidence: Level V (Therapeutic).

Comparison of the Effect of Intralesional Injection of Corticosteroid and Platelet-rich Plasma in Patients with de Quervain’s Tenosynovitis

Background: De Querveins’ tenosynovitis affects the abductor pollicis longus (APL) and extensor pollicis brevis (EPB) tendons in the first dorsal compartment of the wrist. Corticosteroid injection is the mainstay of treatment for those patients who do not respond to conservative management. Platelet-rich plasma (PRP) is a currently used strategy in the clinical practice to provide a regenerative stimulus for tendon healing. Objective: To evaluate the effects of Platelet-rich plasma in the treatment of DQVD in comparison with corticosteroid (CS) injection. Materials and Methods: The present randomized clinical trial had been conducted in the Department of Physical Medicine and Rehabilitation, Bangabandhu Sheikh Mujib Medical University (BSMMU), Shahbag, Dhaka. A total of 100 patients with pain and swelling over the radial aspect of the wrist with positive Finkelstein test were randomly allocated into three groups: group A (received platelet-rich plasma injection), group B (received corticosteroid injection) and group C (received conservative management). The severity of pain and functional status of the wrist joint were recorded according to VAS and Mayo’s wrist score both pre-procedurally on day 0 and post-procedurally at the end of 1st, 3rd and 6th month. Results: The mean age of the participants in group A, B and C were 45.6 (±10.4), 46.9 (±11.3) and 42.4 (±6.3) years respectively. In all groups, majority of the study participants were female and housewives. No significant statistical difference was observed among the groups regarding VAS scores and Mayo’s Wrist Scores at baseline. At the end of 6 months, the reduction of pain in group A was significantly lower than group B (p&lt;0.001). Again, at the end of 6 months, the improvement of Mayo’s Wrist Scores in group A group was significantly higher than group B (p&lt;0.001). In group A, 77.8% reduction of pain score was achieved while in group B, 68.4%reduction of pain score was achieved after 6 month of treatment (p&lt;0.001). Conclusions: Platelet-rich plasma provides better functional outcome than corticosteroid in the treatment of de Quervain tenosynovitis. Bangladesh Medical Res Counc Bull 2023; 49(1): 32-38

Solitary extensor tendon in the third compartment has a companion: variant course of extensor pollicis brevis in third extensor compartment.

Anomalous variants of the extensor tendons in the first and third compartments of the wrist have been described following cadaveric study. Being aware of such variants during either an elective or emergency hand surgery will prove beneficial in the execution of the extensor tendon repairs. A very few clinical reports are available in the literature. We report a rare finding of extensor pollicis brevis tendon accompanying the solitary extensor pollicis longus tendon in the third compartment observed during an emergency trauma surgery.Level of evidence V.

A cadaveric study of first dorsal extensor compartment in Africans: Clinical implications

While several reports have been made regarding the anatomic variations in the first dorsal extensor compartment, very few have emanated from Africa. This study looked at this compartment with respect to variations in the superficial branch of the radial nerve and the enclosed tendons. The first dorsal extensor compartment of the hand was studied in 32 formalin preserved adult African cadavers. The superficial branch of the radial nerve emerged from underneath the brachioradialis 8.4cm(sd±2.2cm) proximal to the radial styloid and branched 6.2cm (sd ±1.5cm) proximal to it as well. This nerve along with the cephalic vein or its tributary transversed part of the compartment in all the hands. A double Extensor pollicis longus was found in one hand. Septations were observed in 31.3 %(n=10) of the hands. Abductor pollicis longus tendon was fused in three hands, and had more than one slip in 94% of the hands. A single extensor pollicis brevis tendon was found all dissected hands. Clinical implications of these findings are highlighted in this work.

Scaphotrapeziotrapezoid joint loading during key pinch grip before and after trapeziometacarpal arthroplasty: a cadaver study

In a previous cadaver study, we directly measured the load acting on the trapeziometacarpal joint for increasingly greater key pinch forces. We noted that the joint load ranges from 2 kg to 4 kg during progressively greater key pinch from 0.5 kg to 1.5 kg. Using the same experimental approach, the aim of the current study was to measure and compare the load acting on the scaphotrapeziotrapezoid joint for the same levels of isometric key pinch force, and how it changes after trapeziometacarpal arthroplasty. We performed a cadaver study using 7 fresh-frozen, unembalmed adult forearms and hands (2 right and 5 left). Thumb pinch was simulated by loading the main actuator tendons involved in the key pinch grip (i.e., adductor pollicis, flexor pollicis longus, extensor pollicis longus, extensor pollicis brevis and abductor pollicis longus tendons). Measurements were made inside the joint using a force-sensing resistor sensor (Tekscan® FlexiForce™ force sensor). Before the trapeziometacarpal joint surgery, median load values recorded in the scaphotrapeziotrapezoid joint were 1.2 kg (IQR, 1.0–1.4), 1.6 kg (IQR, 1.6–2.5) and 2.4 kg (IQR, 2.3–3.4) during 0.5 kg, 1 kg and 1.5 kg key pinch, respectively. After the trapeziometacarpal arthroplasty, median joint contact forces did not change significantly relative to the original configuration. Our findings indicate that the loads measured in the scaphotrapeziotrapezoid joint during a simple key pinch are in fact lower than those measured inside the trapeziometacarpal joint. After trapeziometacarpal arthroplasty, the values are similar with no increase in load, suggesting that clinically asymptomatic scaphotrapeziotrapezoid radiographic involvement may not be a contraindication to arthroplasty.

Morphometry of extensors of the thumb with comprehensive review

This study was aimed to evaluate the anatomical variations and morphometry of long extrinsic tendons of the thumb namely, extensor pollicis longus and extensor pollicis brevis. Fiftyfive upper limbs of formalin embalmed adult cadavers were dissected. The variation in muscle belly, tendon, its course within dorsal wrist compartment and mode of insertion were noted. The extensor pollicis longus was duplicated in 5.5%. Around 25% tendons were fused with extensor pollicis brevis and through the extensor hood insert into the base of the distal phalanx. The extensor pollicis brevis was absent in 2% and tendon was also duplicated in 2%. In case of absent extensor pollicis brevis tendon, one of the slips from the abductor pollicis longus insert into base of the proximal phalanx instead of the extensor pollicis brevis. The extensor pollicis brevis tendon showed various modes of insertion. The overall length of the extensor pollicis longus and extensor pollicis brevis were 121 mm and 90 mm respectively. The thickness of the extensor pollicis longus at the proximal, middle and distal level of insertion were 1.25 mm, 0.76 mm and 0.55 mm respectively, whereas for the extensor pollicis brevis it was 1mm, 0.75 mm and 0.53 mm. The results obtained from this study may be helpful for the hand surgeons in the management of extensor tendon injuries of the thumb, its reconstructive procedures and in differential diagnosis of dorsal wrist pain.

De Quervain's Release (Cadaver)

De Quervain’s release is a surgical procedure performed to curatively treat stenosing extensor tenosynovitis of the first extensor compartment of the wrist, after nonoperative management fails. This procedure involves surgical release of the first dorsal compartment with care taken to fully release the abductor pollicis longus (APL) and extensor pollicis brevis (EPB) tendons from their respective sheaths, while protecting the radial sensory nerve, in order to decompress the extensor tendons. This video outlines the operative technique used by Dr. Asif Ilyas for performing a De Quervain’s release on a cadaveric wrist.

Delayed reconstruction of a missed Extensor Pollicis Brevis and Abductor Pollicis Longus injury using tendon transfers and an onlay tendon graft: a case report

Delayed presentation of extensor tendon injury comes with unique challenges due to retraction of tendons, adhesions and problems of disuse of the muscles. We present a case report of tendon reconstruction eight months after a sharp injury to the Extensor Pollicis Brevis (EPB) and Abductor Pollicis Longus (APL) tendon in zone VIII. The EPB was reconstructed by using an Extensor Indicis Proprius (EIP) to EPB transfer. The APL was found slack due to a large section of pseudotendon. After tenolysis the proximal tendon stump of the EPB was sutured to the APL, thus combining the impaired EPB and APL muscles for APL function. The slack section of pseudotendon of the APL was plicated to restore tension and reinforced with an onlay tendon graft (left-over from the EIP transfer). Outcomes were excellent. This is the first publication to discuss delayed repair of a combined EPB and APL injury and gives insights into the anatomical and biomechanical balance of the thumb extensors. • Delayed reconstruction of tendons is challenging due to retraction of tendons, adhesions and problems of disuse of muscles. • This is the first case report published on delayed repair of a combined APL and EPB injury. • EIP to EPB transfer is a good option for EPB reconstruction. • EIP transfer for extensor tendon reconstruction in zone VII/VIII offers surplus tendon to be used as a separate tendon graft.

Reliability of Extensor Pollicis Brevis (EPB) Entrapment Test in Identifying a Separate Compartment for EPB in Patients with de Quervain Disease.

Background: The presence of a separate compartment for the extensor pollicis brevis tendon (EPB) has an implication in the treatment outcome for de Quervain disease. The EPB entrapment test, proposed by Alexander and colleagues, claims to correlate with the presence of a separate compartment for EPB. The purpose of our study is to evaluate the reliability of the EPB entrapment test in predicting a separate compartment for EPB in patients with de Quervain disease. Methods: This was a prospective observational study involving 50 consecutive patients who underwent de Quervain release by a single surgeon. Preoperatively, EPB entrapment test was performed by the operating surgeon. The outcome of the test was recorded and the presence of a separate compartment for the EPB was determined during surgery. Sensitivity, specificity, positive predictive value and negative predictive value of the EPB entrapment test was determined. Results: EPB entrapment test was positive in 28 of 50 patients. In 21 of them, a separate compartment for the EPB was noted. The positive predictive value of the test was found to be 75.8%. The test had a false positive rate of 26.9%, a false negative rate of 12.5%, sensitivity of 87.5% and specificity of 73%. There is a significant association between a positive EPB entrapment test and the presence of a separate compartment for the EPB (p value <0.001). The sensitivity of the test increases to 95.8% if pain on both extension and abduction of the thumb is considered a positive response. Conclusions: The EPB entrapment test is a reliable clinical test to look for the presence of a separate compartment for EPB. Considering the response of pain on both extension and abduction of the thumb further improves the sensitivity of the test. Hence, we suggest including this response also as a positive test. Level of Evidence: Level II (Diagnostic).

Prevalence of Septated First Dorsal Compartment Among Iranian Patients with De Quervain Tenosynovitis

Background: A septum in the first extensor compartment and variation of abductor pollicis longus (APL) and extensor pollicis brevis (EPB) tendons affect the development and treatment of the de Quervain disease. This study aimed to determine the prevalence of septum and the number of APL and EPB tendons in Iranian surgical de Quervain patients. Methods: In this case series, we evaluated 37 consecutive wrists from September 2019 to April 2020 that were evaluated and surgically explored by the same senior surgeon; and the number of tendons and the existence of septum were recorded. Results: Patients were mainly women (24 [67.6%]), and the mean age was 50.43 ± 16.42 years. Seven (18.9%) patients had one, 23 (62.2%) had two, and 7 (18.9%) patients had three APL tendons. All patients had EPB tendons, 34 (91.9%) had 1 EPB tendon, and 3 (8.1%) had 2 EPB tendons. A septum was observed in 23 (62.2%) patients. Conclusion: The most functional variation in Iranian patients consists of 2 APL tendons and 1 EPB tendon. Also, most affected wrists had a septum in the first extensor compartment.