In patients with severe, long-standing carpal tunnel syndrome and thenar muscle atrophy, nerve decompression alone is unlikely to restore thumb opposition. A multitude of tendon transfer techniques have been described to restore thumb opposition. We describe the technique of an endoscopic carpal tunnel release with opponensplasty using ring finger flexor digitorum superficialis (FDS) tendon under Wide Awake Local Anaesthesia No Tourniquet (WALANT) and ultrasound assistance.

BACKGROUND: The forearm flexor-pronator muscles act as a dynamic elbow stabilizer against elbow valgus load during baseball pitching. The elasticity of these muscles increases with pitching. However, it is unclear whether increased muscle elasticity is associated with greater elbow valgus torque during pitching. This study aimed to determine the relationship between the elasticity of the forearm flexor-pronator muscles and elbow valgus torque during pitching in young baseball pitchers.
METHODS: We recruited 124 young baseball pitchers aged 9 to 12 years. The exclusion criteria included current pain with pitching, history of surgery on the tested extremity, or injuries on the tested extremity within the past 12 months. Before the examination, participants completed a questionnaire about their age, height, weight, dominant arm, and practice time per week. The strain ratios of flexor carpi ulnaris (FCU), flexor digitorum superficialis (FDS), and pronator teres as the index of muscle elasticity were measured using ultrasound strain elastography. Participants pitched 3 fastballs at a distance of 16 m (52 ft 6 in) with maximum effort while wearing a sensor sleeve that recorded the elbow valgus torque. A multiple linear regression analysis was conducted to examine the association between muscle elasticity and elbow valgus torque, adjusting for age, height, weight, and practice time.
RESULTS: The final analysis included 107 pitchers. After adjusting for covariates, increased strain ratio of the FCU was significantly associated with greater elbow valgus torque (coefficients = 0.038, 95% confidence interval, 0.016-0.059, P < .001). Similarly, increased strain ratio of the FDS was significantly associated with greater elbow valgus torque (coefficients = 0.027, 95% confidence interval, 0.013-0.042, P < .001).
CONCLUSIONS: The high elasticities of the FCU and FDS were associated with greater elbow valgus torque during pitching in young baseball pitchers. The high elasticity of these muscles is a protective response and may be necessary for young baseball pitchers with greater elbow valgus torque during pitching. Among young baseball pitchers with greater elbow valgus torque, those who are unable to produce the higher elasticities of these muscles could have greater elbow valgus load during pitching and be at a higher risk for elbow injuries. The measurement of the elasticities of the FCU and FDS may be useful for identifying young baseball pitchers at risk of sustaining elbow injuries.

Duplication of the flexor digitorum profundus (FDP) tendon is an extremely uncommon anatomical anomaly found within the flexor digitorum superficialis (FDS) muscle, with minimal documentation in the current literature. We present the case of a 45-year-old female manual laborer who exhibited symptoms suggestive of trigger finger in her right middle finger. Surgical exploration uncovered a duplicated FDP tendon, a previously unreported anatomical anomaly in this context. Despite attempting conservative treatment initially, surgical intervention involving release of the A1 pulley, excision of the A1 pulley, and identification of the duplicated tendon was performed. The unusual nature of this anatomical variation highlights the need for additional research into its clinical significance and treatment options. This case highlights the significance of conducting comprehensive anatomical assessments to diagnose and treat uncommon variations within the FDS muscle. It underscores the continued need for collaborative research to enhance treatment approaches, especially in instances where trigger finger symptoms are present.

The feasibility of a pedicled flexor digitorum superficialis muscle flap was studied in 10 fresh cadavers. The number, length and distance from the flexion wrist crease of muscular branches from the ulnar artery in the distal 10 cm of the forearm were recorded. The mean number of muscular branches was 2.7 (range 1-4). The mean distance of the most distal branch was 35 mm (range 26-40) from the proximal wrist flexion crease. Its mean length was 20 mm (range 16-26). A partial muscle flap was raised on the most distal branch and transposed over the median nerve in the distal forearm. Dissection and transposition of this flap were feasible in all specimens. The reliable pattern of muscular branches to the flexor digitorum superficialis allows the elevation of a pedicled partial muscle flap that can cover the median nerve in the distal forearm.Level of evidence: V.

暂无摘要。

A giant cell tumor of the tendon sheath (GCTTS) presents as a rare neoplasm demanding a heightened index of suspicion for precise diagnostic evaluation, especially when manifesting in the digital phalanges, as it is part of a group of neoplasms known as tenosynovial giant cell tumors (TCGTs). An accurate and timely diagnosis is crucial, as it significantly enhances treatment outcomes for this heterogeneous group of lesions. We describe the case of a male patient who presented with multiple nodules in the fourth finger of his left hand and was ultimately diagnosed with a localized form of a GCTTS, an unusual presentation for localized forms of this entity. Our objective is to outline the diagnostic and therapeutic approach, discussing options for differential diagnosis and treatment modalities. To achieve this, we conducted a literature review and compared our findings and the observed evolution in our patient. Early recognition of hand tumors allows for timely diagnosis, facilitating optimal resections during surgical procedures. This, in turn, reduces morbidity and enhances the functionality of the affected extremity, as detailed in the current case.

OBJECTIVE: To locate the intramuscular nerve branches of the flexor digitorum superficialis (FDS) and determine the accurate site for botulinum toxin injection.
METHODS: This study anatomically dissected 24 arms of 12 fresh adult cadavers to find intramuscular nerve endings in the FDS. The motor branch points (MBPs), proximal limit points (PLPs), and distal limit points (DLPs) of the terminal intramuscular nerve endings were identified. These three parameters were expressed in longitudinal and transverse coordinates in relation to the FDS driving as a reference line.
RESULTS: The mean length of the reference line was 234.6 ± 11.2 mm. In the longitudinal coordinate, the MBPs, PLPs, and DLPs were located at 41.6% (standard deviation (SD) 2.6%), 35.1% (SD 4.1%), and 53.4% (SD 4.6%) of the reference line in the first main branch and 72.4% (SD 4.5%), 67.5% (SD 1.5%), and 82.0% (SD 5.7%) in the second main branch, respectively. The mean value of the transverse coordinate was not greatly deviated from the reference line.
CONCLUSIONS: The MBPs of the first and second main branches are located approximately 41.6% and 72.4% of the reference line, which considers the FDS direction, respectively. This finding helps determine the optimal injection site for botulinum toxin in the FDS.

Anomalous muscle bellies in the forearm generally are asymptomatic and appreciated in an academic sense during cadaveric dissections. Few prior anatomic variations in muscle bellies have been described with symptoms, and are associated even more rarely with carpal tunnel syndrome (CTS). We discuss the evaluation and management of a case of CTS associated with a muscle belly of the flexor digitorum superficialis to the index within the carpal tunnel.

Recent dissection studies resulted in the introduction of the term \"chiasma antebrachii\", which represents an intersection of the flexor digitorum superficialis (FDS) tendons for digits 2 and 3 in the distal third of the forearm. This retrospective investigation aimed to provide an MRI-based morphologic analysis of the chiasma antebrachii. In 89 patients (41 women, 39.3 ± 21.3 years), MRI examinations of the forearm (2010-2021) were reviewed by two radiologists, who evaluated all studies for the presence and length of the chiasma as well as its distance from the distal radioulnar and elbow joint. The chiasma antebrachii was identified in the distal third of the forearm in 88 patients (98.9%), while one intersection was located more proximally in the middle part. The chiasma had a median length of 28 mm (interquartile range: 24-35 mm). Its distances to the distal radioulnar and elbow joint were 16 mm (8-25 mm) and 215 mm (187-227 mm), respectively. T1-weighted post-contrast sequences were found to be superior to T2- or proton-density-weighted sequences in 71 cases (79.8%). To conclude, the chiasma antebrachii is part of the standard FDS anatomy. Knowledge of its morphology is important, e.g., in targeted injections of therapeutics or reconstructive surgery.

We investigated thumb joint stability and patient-reported and functional outcomes a minimum of 1 year after flexor digitorum superficialis opponensplasty and ligament reconstruction in 23 thumbs of 20 consecutive children with radial longitudinal deficiency. In total, 15 thumbs had preoperative multidirectional instability in the metacarpophalangeal joint. We reconstructed 22 ulnar and 16 radial collateral ligaments. At follow-up, all the metacarpophalangeal joints were stable ulnarly. Seven metacarpophalangeal joints were unstable radially despite ligament reconstruction but had no related complaints. We recommend the flexor digitorum superficialis opponensplasty as a safe and reliable procedure in hypoplastic thumbs to create stability and augment thumb strength.Level of evidence: IV.