Flexor Digitorum Superficialis Function Research Articles

Evaluation of flexor digitorum superficialis function in adolescent baseball players.

Increased flexor digitorum superficialis (FDS) tendon activity can be a therapeutic target for elbow disorders in adolescent baseball players. The proportion of adolescent baseball players who can use FDS independently is unknown, and which finger is most often used remains unclear. This study investigated whether adolescent baseball players intentionally used FDS on each finger. Adolescent baseball players were recruited and assessed for FDS function for each finger using the standard technique. Sixty-nine participants (mean age: 10.4 years) were recruited. Participants numbered 33, 56, 59, and 25 on the throwing side and those numbered 28, 46, 54, and 33 on the nonthrowing side could independently flex the proximal interphalangeal joint while holding their palms in the index, middle, ring, and small fingers, respectively. When assessing both throwing and nonthrowing participants, a significant number of participants could independently flex the proximal interphalangeals of the ring and middle fingers but had difficulty with the index and small fingers (P<.001). No significant difference was noted between the throwing and nonthrowing participants in any finger (P>.05). One study reported that participating baseball players with elbow pain have more medial elbow joint space than those without pain symptoms. In another study on finger movements during pitching motion, the force of the thumb, index, middle, and ring fingers was greatest immediately before maximum external rotation. According to both reports, FDS function, especially in the index finger, can be a therapeutic target for medial-sided elbow injuries in adolescent baseball players.

Return-to-play outcomes in high school baseball players after ulnar collateral ligament injuries: dynamic contributions of flexor digitorum superficialis function

Ulnar collateral ligament (UCL) injuries are common in baseball pitchers. The purpose of this study was to evaluate changes to medial elbow joint laxity under valgus stress, as well as under valgus stress with flexor digitorum superficialis (FDS) contraction, and its ability to predict rehabilitation outcomes. Sixty-one UCL injuries were diagnosed. All patients were high school students who initially received rehabilitation treatment. Rates of return to play and return to the same level of play or higher (RTSP) were calculated and correlated with joint gapping under the following conditions: elbow gravity valgus stress and intra-articular ring-down artifact (RDA) at rest, elbow gravity valgus stress, and elbow gravity valgus stress with maximum FDS contraction. The overall RTSP rate in patients receiving nonoperative treatment was 83.6% (51 of 61 patients). The RDA at rest significantly differed between the RTSP and non-RTSP groups, with an odds ratio of 17.5. This result indicated that the RDA could be a predictor of rehabilitation outcomes. Moreover, there were significant differences in the RDA under gravity valgus stress conditions with FDS contraction between the 2 groups, with an odds ratio of 98.0. Multivariate logistic regression analysis identified 1 variable (RDA under valgus stress with FDS contraction) as the most significant predictive factor for successful treatment of UCL elbow injury. UCL injuries in high school baseball players can be successfully treated nonoperatively in most cases. Stress ultrasound with FDS muscle contraction can help predict the potential for RTSP.

Quantitative examination of isolated finger flexion associated with function of the flexor digitorum superficialis.

[Purpose] Isolated finger flexion associated with function of the flexor digitorum superficialis has been qualitatively assessed using standard and modified tests. The purpose of this study was to quantify isolated finger flexion in healthy participants. [Participants and Methods] We assessed 100 volunteers (mean age: 44.6 years) without upper limb dysfunction using the standard and modified flexor digitorum superficialis tests. The sum of the isolated active flexion angles of the metacarpophalangeal and proximal interphalangeal joints of the test finger was also calculated, with the other three fingers held in an extended position with our original jig. [Results] The mean isolated flexion angles were, respectively, 152.4° and 154.8° for the right and left index fingers, 161.1° and 160.4° for the middle fingers, 160.6° and 158.2° for the ring fingers, 129.4° and 134.6° for the independent flexor digitorum superficialis function, 85.8° and 74.7° for the common flexor digitorum superficialis function, and 75.8° and 71.2° for absent flexor digitorum superficialis function in the small finger. The functional variations of the flexor digitorum superficialis of the small fingers showed symmetry in 65.0% of the fingers but asymmetry in 35.0%. [Conclusion] The data obtained in this study provide normal reference values for the examination of independent movement disorders of the fingers.

Corrigendum to: Godwin Y, Wheble GAC and Feig C. Assessment of the presence of independent flexor digitorum superficialis function in the small fingers of professional string players: Is this an example of natural selection? J Hand Surg Eur. 2013, 39: 93-100.

The corresponding author details for the above article have been modified. The online version of the article has been updated.

Assessment of the presence of independent flexor digitorum superficialis function in the small fingers of professional string players: Is this an example of natural selection?

This study estimated the prevalence of independent flexor digitorum superficialis function in the small fingers of 90 violin and viola players. The hypothesis tested was that the independent digital movements required in this population would select out those with absent flexor digitorum superficialis function. Professional string players were tested clinically, using standard and modified tests, for flexor digitorum superficialis function. Two additional physical tests were applied: the gap and stretch tests. These tests assess ring finger movement once the small finger is placed and the instrument is held in the chin-hold position. A statistically significant reduction in the prevalence of absent flexor digitorum superficialis function was confirmed in the musicians compared with a control group and published meta-analysis. This suggests that independent flexor digitorum superficialis function is important for professional musicians playing at an elite level.

A New Examination Method for Anatomical Variations of the Flexor Digitorum Superficialis in the Little Finger

BackgroundCurrent examination methods to assess the anatomical variations of flexor digitorum superficialis (FDS) tendon in the little finger necessitate a strong external force applied by the examiner and cause false negatives. A new examination method was designed to detect the variations more accurately.MethodsWe examined the little fingers of 220 adult hands (110 subjects) by 2 methods: the expanded examination method advocated by Tan et al., and a new examination method. Variations of the FDS in the little finger were examined by both methods and categorized separately as having independent FDS function, FDS connection to the tendons of the ring finger or of the multiple adjacent fingers, and functional substitution of the flexor digitorum profundus (FDP) with or without tendinous connection to the ring or multiple adjacent fingers. By our new method, we could further divide the FDS connection or FDP substitution with connection to the ring finger into 2 subtypes: loose and close connections. Data were reported as case numbers and percent. Date on symmetry were statistically analyzed by matched case-control studies.ResultsAmong 220 hands, 113 hands (51.4%) had independent FDS function by the new examination method, which was lower than the incidence (55.5%) detected with the existing expanded examination method. In the hands with connections between FDS tendons of the little and the ring fingers, 32 hands (14.5%) demonstrated loose and 37 (16.8%) close connections. Three hands (1.4%) had loose and 19 (8.6%) had close FDP substitution with tendinous connection to the ring finger. Among 110 hands without independent FDS function, variants of 42 hands (38.2%) were asymmetric. There was no statistical significance in symmetry of variations.ConclusionsThis new examination method offers other assessment variations of FDS tendon in the little finger. We recommend using this test to assess the variations and function of the FDS of the little finger.

Congenital Absence of Flexor Digitorum Superficialis: Implications for Assessment of Little Finger Lacerations

Absence of flexor digitorum superficialis function in the little finger is a relatively common congenital anomaly that can complicate assessment of little finger injuries. We reviewed the prevalence of unilateral and bilateral absence of superficialis function in the published literature. In appropriate studies identified (1352 people), the anomaly was unilateral in 92 individuals (6.8%) and bilateral in 81 (6.0%). If superficialis function is absent in one little finger, the probability of absence in the opposite hand is 0.64. If superficialis function is present, the probability of absence in the other little finger is 0.02 (1 in 50). Absence of little finger superficialis function in one hand is therefore not a reliable indicator of this function in the opposite hand.

Variations of the Flexor Digitorum Superficialis As Determined by an Expanded Clinical Examination

Current examination techniques do not detect the wide clinical variability of the flexor digitorum superficialis (FDS). Modification of current examination techniques may be necessary to detect anomalies and lead to more accurate diagnosis. We examined 500 subjects using an expansion of current techniques to elicit the range of variations in FDS function discernable on clinical examination. FDS function was evaluated by asking subjects to flex the finger of interest while all other fingers were held fully extended at the metacarpophalangeal and interphalangeal joints. Isolated flexion at the proximal interphalangeal (PIP) joint indicated independent FDS function. Obligatory flexion at the distal interphalangeal (DIP) joint indicated flexor digitorum profundus (FDP) activity. Because FDS activity could not be evaluated if concurrent FDP activity was present, these fingers were designated as having FDP substitution. Difficulty isolating PIP joint flexion suggested connections to adjacent FDS or FDP, prompting the examiner to serially release adjacent fingers while observing for improvement in PIP or DIP range of motion. Independent FDS function was most consistently present in the ring and middle fingers, less so in the index finger, and least in the small finger. Variations included FDP substitution or connections to flexor tendons in 1 or 2 adjacent fingers with or without evidence of FDP substitution. Absent FDS function cannot be presumed in any subject based solely on clinical examination of a single digit. Current examination techniques are inadequate to discern among the multiple variations of FDS function. An expanded examination technique is recommended for accurate diagnosis of FDS function following flexor tendon injury.

FUNCTIONAL ABSENCE OF FLEXOR DIGITORUM SUPERFICIALIS TO THE LITTLE FINGER AND ABSENCE OF PALMARIS LONGUS – IS THERE A LINK?

We examined 150 men and 150 women aged 18–40 years to assess flexor digitorum superficialis function to the little finger and the incidence of palmaris longus absence. All patients had flexor digitorum superficialis function to the little finger assessed by standard and modified tests. The presence or absence of palmaris longus was assessed by clinical inspection. Following modified testing, ten subjects (14 hands) displayed absolute superficialis deficiency to the little finger. Forty-nine subjects had unilateral absence of palmaris longus (16%). This tendon was absent bilaterally in 26 subjects (9%). On combining the clinical findings, one subject had unilateral absence of flexor digitorum superficialis function to the little finger with contralateral absence of palmaris longus, and one subject had bilateral absence of flexor digitorium superficialis function with unilateral absence of palmaris longus. We conclude that there is no link between an absent little finger flexor digitorium superficialis and an absent palmaris longus.

A prospective study of flexorivendon repair in zone 5

A prospective study,of postoperative mobilization of flexor tendon repairs in zone 5 was conducted over a 2-year period between 1994 and 1996 using a controlled active motion (active extension — active flexion) regimen of mobilization. Fifty-two patients, who had a total of 151 flexor digitorum superficialis (FDS) and 103 flexor digitorurn profundus (FDP) divisions, were available for review at a mean follow-up of 10 months. Of the 161 fingers with division of one or both flexor tendons, 66% exhibited independent FDS function and 90% achieved good or excellent results of digital range of motion. No rupture of an FDP tendon repair occurred during the study period. The data allowed us to define a new method of classifying the results of treatment of these injuries in terms of the injured wrists as a whole and not simply as a series of isolated observations for each individual finger with divided flexor tendons. The results of recovery of independent FDS action and range of finger movement achieved for injuries in which the flexors of all four fingers had been divided indicate a statistically significant interdependence of injuries of finger flexors of adjacent fingers at the wrist. Multivariate analysis showed the presence of a “spaghetti wrist” injury to have a significant adverse effect on the recovery of the independent FDS action but not on the recovery of the digital range of motion.

A biomechanical study of the flexor digitorum superficialis: Effects of digital pulley excision and loss of the flexor digitorum profundus

Many reports have been devoted to characterizing the significance of the pulleys for the flexor digitorum profundus (FDP). However, no comparable work has been published on the flexor digitorum superficialis (FDS). This study characterized the FDS in a human cadaver model. Eleven fresh-frozen cadaver hands were used. By using a tensiometer, data were gathered for tendon excursion, tendon load, and work of flexion. Changes in efficiency were caused by excision of annular pulleys A1, A2, A3, and the palmar aponeurotic pulley. We also measured the effect of FDP excision on FDS efficiency. Sectioning of the A2 and A3 pulleys together caused statistically significant losses of efficiency in all three parameters (work, load, and excursion). When the FDP was removed from a finger with an intact pulley system, losses in both work and excursion efficiencies were significant. Removing the FDP while cutting different pulleys caused significant decrease in FDS excursion efficiency. We conclude that A2 and A3 are the most important pulleys for maintaining normal FDS function, and that the presence of the FDP in the digital sheath is essential for optimal FDS excursion efficiency.

Isolated avulsion of the flexor digitorum superficialis tendon

Isolated, closed avulsion of the flexor digitorum superficialis tendon at its insertion is thought to be a rare diagnostic entity, with only six cases reported in the literature. However, we have diagnosed and treated 11 such cases, each presenting with a tender palmar mass and loss of active flexor digitorum superficialis function. Some patients had proximal interphalangeal joint contractures. Upon exploration, the retracted superficialis tendon was found to ensnare the profundus tendon at the level of the A1 pulley. Following tenolysis, flexor digitorum superficialis tendon excision, and in selected patients capsulotomies, each patient achieved good functional capacity.

Clinical evaluation of flexor tendon function in the small finger

Patients frequently present to the emergency department with hand injuries. Standard examination includes testing each digit for flexor function. The flexor digitorum superficialis (FDS) to the small finger has been shown to have variable anatomy and clinical examination. We prospectively examined 100 subjects (200 hands) for small finger FDS function by standard and modified testing. We found that 70 small flexors (35%) showed absent FDS by standard testing, whereas only eight fingers (4%) had absent FDS by modified testing. FDS function to the small finger is frequently unilateral. We conclude that modified testing is the only way to accurately test for small finger FDS function and that the use of this simple clinical examination may prevent unnecessary referral to a hand surgeon.

Variations of the flexor digitorum superficialis of the small finger

Normal functional variations of the flexor digitorum superficialis were clinically determined by use of the standard and modified superficialis flexion tests in 50 normal subjects. Forty hands of 20 cadavers were dissected to correlate the anatomic variations with the clinical findings. A flexor digitorum superficialis-independent pattern was found 58% of the time. A flexor digitorum superficialis-common pattern was found 21% of the time. A flexor digitorum superficialis-absent pattern was found 21% of the time. The right and left hands were asymmetric 26% of the time. All cadaver hands had a flexor digitorum superficialis tendon present in the palm and finger. The variability in flexor digitorum superficialis function may be explained by interconnections between the flexor digitorum superficialis of the small finger and either the flexor digitorum superficialis of the ring finger or the flexor digitorum profundus of the small finger.