Palmaris Longus Research Articles

A full thickness and partial rotator cuff tear with retraction of fibers and reconstruction with palmaris longus graft

A full thickness and partial rotator cuff tear with retraction of fibers and reconstruction with palmaris longus graft

Management Options and Clinical Outcomes After Flexor Tendon Ruptures Following Volar Plating of Distal Radius Fractures.

The transition to volar locking plates for the treatment of distal radius fractures has improved patients' range of motion, reduced extensor tendon issues, and hastened return to activity compared to older fixation methods or nonoperative treatment. One drawback to volar plating is the potential for flexor tendon ruptures due to aberrant plate or screw placement. This study aims to describe the reconstruction options and patient outcomes after flexor tendon rupture due to volar plating. This is a single-institution, retrospective review of patients who presented with flexor tendon rupture from 2014 to 2023 after a distal radius fracture previously managed with a volar plate. Patient demographics, operative details, range of motion, complications, and patient-reported outcomes were collected. Ten patients presented with flexor tendon ruptures after volar plating for distal radius fractures from 2014 to 2023. The most common rupture was flexor pollicis longus (FPL) in 7 patients, followed by index finger flexor digitorum profundus (FDP) in 2 patients, and small and ring finger FDP rupture in 1 patient. Flexor pollicis longus (FPL) was reconstructed with a palmaris longus (PL) graft in 4 patients, ring finger flexor digitorum superficialis transfer in 2 patients, and repaired primarily in 1 patient. All patients with FPL ruptures regained functional thumb interphalangeal flexion except for 1 patient who reruptured 4 weeks after surgery. Flexor tendon ruptures can occur following volar plating of distal radius fractures, even years after fixation of the fracture. These are attritional ruptures and generally reconstructed with tendon grafting of transfer, providing functional flexion of the affected digit.

018. Supraclavicular Flap and Reconstruction With Radial Forearm Flap In Basal Cell Carcinoma Of The Buccal Region: A Rare Case Report

Background: Basal cell carcinoma (BCC) progression can invade surrounding tissues, causing local destruction and disfigurement. About 85-90% cases of BCC occur on the head, greatly affecting facial appearance of patients. Functional or cosmetic concerns require skin flap or graft. Case: A patient presented with a wound on his left cheek for 8 years, bleeds easily and painful. There is a muscle-based ulcer, penetrating the oral cavity and a post-biopsy wound is covered with granulation tissue. Laboratory examination showed moderate anemia and chest x-ray did not show any metastases. A supraclavicular flap and intraoral and supraclavicular insertion and intraoral and supraclavicular insertion were performed. In addition, harvesting of the radial forearm flap and partial palmaris longus tendon was conducted. Conclusion: Reconstruction of facial defects in different facial esthetic units is essential following excision of BCC. But it is necessary to plan the stages of reconstruction when more than one facial region is involved. Surgeon skills, patient’s preference, defect size and location are important determinants of esthetic outcomes

Two-Stage Flexor Tendon Reconstruction for Finger Contracture Secondary to Phlegmon: A Case Report

Flexor tendon reconstruction is a complex surgical procedure that requires great precision and specialized expertise. It remains a preferred treatment for patients with neglected lacerations of the digital flexor tendon and after the failure of flexor tendon repair. Improvements in tendon repair methods and follow-up techniques have enhanced outcomes after flexor tendon grafting. Case Presentation: A 14-year-old girl with a history of a phlegmon of the 4th finger of the right hand, treated with antibiotics and drainage. The evolution is marked after 2 years by the progressive development of a flexion contracture of the proximal interphalangeal (PIP) joint. On examination, there is a flexion attitude and an inability to extend the PIP joint without vascular or nervous disorders. A two-stage reconstruction was performed using the palmaris longus tendon as a graft. With a follow-up of 3 years, the girl has recovered complete flexion and has limited extension to 25° at the PIP joint. An arthrolysis was proposed, but the girl refused, and she is satisfied with the results.

Physiological and Functional Restoration of the Modiolus Using a Double Tendon Sling in Patients With Full-Thickness Oral Defects.

Reconstruction of the oral modiolus should be considered for facial defects involving the lip and cheek. We have performed free flap reconstruction using a novel technique that includes a vertical and a horizontal sling for full-thickness defects involving the oral commissure. We used a free radial forearm flap and the palmaris longus tendon to correct lip and cheek defects in 6 patients (3 men, 3 women; age, 55-84 years). The tendon was divided into 2 portions for use as the double sling. One sling was used to connect the upper and lower stumps of the orbicularis oris in the vertical direction and the other to connect the vertical sling and masseter muscle. The outcomes assessed were esthetic appearance and functional results. The facial defects ranged in size from 3.0 cm × 4.0 cm to 7.0 cm × 6.0 cm and the mucosal defects from 1.5 cm × 4.0 cm to 6.5 cm × 5.0 cm. The length of the harvested tendon ranged from 11.5 to 13.5 cm. All flaps survived without complications. Good esthetic outcomes were achieved (excellent facial appearance, n = 1; no lip deviation or drooping, n = 5). Functionally, all patients had acceptable mouth opening and were able to eat a regular diet. Good physiological and functional results can be achieved using a double tendon sling for reconstruction of the modiolus in patients with full-thickness defects involving the oral commissure.

Nerve compression after opponensplasty: a cadaveric study

Background: We describe the differences in thumb opposition between different opponensplasty tendon transfers and determine the immediate pressure on the median and ulnar nerves incurred by each transfer. Methods: Using fresh frozen cadavers (8 specimens), opponensplasties were performed using extensor indicis proprius (EIP), flexor digitorum superficialis (FDS) with flexor carpi ulnaris (FCU) pulley, palmaris longus (PL, Camitz procedure), and PL utilizing the thenar fascia as a pulley (PLwP). Each tendon transfer was tensioned, and the thumb flexion, abduction and pronation were measured. The pressure on the median and ulnar nerves were measured for each tendon transfer at varying tensions. Results: There were no differences seen in flexion or pronation between any of the four tendon transfers. FDS, PL and PLwP demonstrated more abduction than the EIP transfer, however differences were less than 10°. EIP and FDS transfers caused significantly more pressure on the median nerve than PL or PLwP at high tendon tensions. Both EIP and FDS tendon transfers caused significantly more pressure on the ulnar nerve than PL or PLwP, and the pressure increased as tension on the transfer increased. No pressure differences were seen between PL and PLwP. Conclusions: No significant differences were seen in thumb flexion or pronation between the four tendon transfers. Differences were seen for abduction with EIP showing the least amount of abduction. EIP and FDS caused more median nerve compression than PL transfers at high tension. Both EIP and FDS tendon transfers cause more ulnar nerve compression than PL transfers at all tensions. Level of Evidence Level: V

An unreported variant of palmaris longus muscle.

Palmaris longus is a highly variable muscle of the forearm. Knowledge of its variability is of importance to plastic surgeons, hand surgeons and radiologists. During our routine dissection classes for undergraduate medical students, a peculiar palmaris longus muscle was noted in the left upper limb of an adult male cadaver. The muscle had a fleshy belly in the middle and two tendons: a proximal and distal. The distal tendon of palmaris longus gave origin to a variant fleshy slip of muscle which was inserted partly to the pisiform bone and partly merged with the hypothenar muscles. The ulnar nerve and artery passed deep to this variant fleshy slip. The ulnar artery was tortuous both proximal and distal to this slip. The distal loop of the ulnar artery was very superficial and was in the median position. Both the palmaris longus and the variant fleshy slip were innervated by median nerve.

The Figure-of-Eight Ligament Reconstruction in Thumb Carpometacarpal Instability: Surgical Technique and Clinical Outcomes

This study reviewed the results of the figure-of-eight ligament reconstruction, a technique used in the surgical management of thumb carpometacarpal (CMC) instability. This technique establishes joint stability through forces originating within the CMC joint, providing volar and dorsal support. We evaluated the outcomes of 15 patients with nontraumatic, nonarthritic thumb CMC instability treated with the figure-of-eight ligament reconstruction technique. This technique involves routing a graft of the palmaris longus tendon through the base of the first metacarpal and trapezium bone in a figure-of-eight fashion. Preoperative visual analog scale (0-100) for pain and Michigan Hand Outcomes Questionnaire total scores were compared with 3- and 12-month postoperative scores. Secondary outcomes included strength, range of motion, patient satisfaction, return to work, and complications. A significant improvement between intake and 12 months after surgery was observed for both Michigan Hand Outcomes Questionnaire total scores (53, SD 3 vs 70, SD 4) and visual analog scale pain scores (63, SD 4 vs 36, SD 7). Additionally, after surgery, restored thumb CMC joint stability was reported for all patients. Strength and range of motion improved between intake and 12 months after surgery. The median return to work was 6 weeks. Nine (60%) patients rated their satisfaction as "excellent" or "good," and 11 (73%) patients said that they would undergo the surgery again. The figure-of-eight ligament reconstruction significantly improves pain and function in patients with thumb CMC instability while restoring joint stability and preserving range of motion, making it a suitable technique. Therapeutic IV.

Ulnar Collateral Ligament Reconstruction Utilizing a 3-Strand Palmaris Tendon Autograft With a Hybrid Linear Construct

The integrity of the medial ulnar collateral ligament (UCL) of the elbow is vital for the throwing athlete. Although newer techniques exist, reconstruction remains the gold standard for full-thickness UCL tears. An increase in throwing velocity, inadequate recovery, and early sports specialization have contributed to increased rates of UCL injury. As increasing numbers of athletes undergo UCL reconstruction, we continue to search for the optimal technique to return athletes to the same level of competition. We present a UCL reconstruction utilizing a 3-stranded palmaris longus tendon autograft with an inlay linear construct.

Prevalence of the Absence of the Palmaris Longus and Functional Flexor Digitorum Superficialis of the Little Finger in the Indian Population.

Background The absence of the palmaris longus (PL) varies with race. The presence of a functional flexor digitorum superficialis (FDS) of the little finger also varies widely. The aim of this study is to determine the prevalence of the absence of the PL and functional FDS of the little finger in the Indian population. Materials and Methods This is a prospective observational study conducted as a part of the Indian normative data project of the Indian Society for Surgery of the Hand. The presence of the PL was assessed by Schaeffer's test. The function of the FDS was assessed by the standard test and modified test and its function designated as absent, present independently, or present combinedly with the ring finger FDS. Results A total of 200 volunteers including 84 males and 116 females in the 21- to 60-year age group were examined. Of the 400 hands examined, the PL was absent in 26 upper limbs (6.5%). The PL was absent unilaterally in 12 individuals (6%) and bilaterally in 7 individuals (3.5%). Of the 400 little fingers examined, FDS function was absent in 72 fingers (18%), while 67 fingers (16.75%) had a common function and 261 fingers (65.25%) had an independent function. Only 2% had a bilateral absence of both the PL and functional FDS tendons and 5% had a unilateral absence of both tendons. Conclusion The PL and FDS of the little finger were more absent in the right side than in the left side, but the difference was not statistically significant. There was no significant association between the absence of the PL and the absence of the functional FDS of the little finger.

Enhancing Lower Eyelid Suspension Outcomes Through Pre-surgical Facial Nerve Reanimation: A Comparative Study.

Lower eyelid suspension, a common therapeutic procedure for facial paralysis-induced eyelid retraction, faces challenges due to high recurrence in patients lacking facial muscle function and impedes wider adoption. This research aims to explore the potential effects of restoring orbicularis oculi muscle tension through facial nerve reanimation prior to lower eyelid suspension and to define the indications for lower eyelid suspension. The study encompassed 32 individuals with complete facial paralysis, segmented into group A (reanimation group) and group B (non-reanimation group), based on whether the orbicularis oculi muscle's tension was restored through facial nerve reconstruction prior to lower eyelid suspension. Subjective assessments of eyelid closure (the inter-eyelid gap upon gentle closure) and objective methods measures of scleral show (the distance from the pupil's center to the lower eyelid margin, MRD2) were used to provide a comprehensive analysis of long-term effectiveness. The group A exhibited significantly greater long-term improvement in lagophthalmos and lower eyelid ectropion. The alterations in MRD2 measured 2.66 ± 0.27mm in the group A versus 2.08 ± 0.53 mm in the group B, denoting a statistically significant variance (p < 0.001). Moreover, while the ratio of MRD2 preoperative 6 months postoperative revealed no significant difference between groups, a significant difference emerged in 12 months postoperative (group A: 1.02 ± 0.21; group B: 1.18 ± 0.24; p < 0.05), with the values in group A closer to 1, indicative of enhanced symmetry. Restoring the tension in the orbicularis oculi muscle through facial nerve reconstruction prior to palmaris longus tendon sling could effectively sustain long-term outcomes of lower eyelid retraction correction and reduce the recurrence rate. This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Optimized uniform sampling and validation of fiber tracts from magnetic resonance tractography for in vivo architectural measurement of human forearm muscles.

In vivo muscle architectural parameters can be calculated from the fiber tracts using magnetic resonance (MR) tractography. However, the reconstructed tracts may be unevenly distributed within the muscle volume and there lacks commonly used metric to quantitatively evaluate the validity of the tracts. Our objective is to measure forearm muscle architecture by uniformly sampling fiber tracts from the candidate streamlines in MR tractography and validate the reconstructed fiber tracts qualitatively and quantitatively. We proposed farthest streamline sampling (FSS) to uniformly sample fiber tracts from the candidate streamlines. The method was evaluated on the MR data acquired from 12 healthy subjects for 17 forearm muscles and was compared with two conventional methods through uniform coverage performance. Anatomical correctness was verified by: 1. visually assessing fiber orientation, 2. checking whether architectural parameters were within physiological ranges and 3. classifying architectural types. The proposed FSS yielded optimal uniform coverage performance among the three methods (P<0.05). FSS reduced the sampling of long tracts (10% fiber length reduction, P<0.05), and the estimated architectural parameters were within the physiological ranges (P<0.05). The tractography visually matched cadaveric specimens. The architectural types of 16 muscles were correctly classified except for the palmaris longus, which exhibited a linear arrangement of fiber endpoints (R2 = 0.95±0.02, P<0.001). The proposed FSS method reconstructed uniformly distributed fiber tracts and the anatomical correctness of the reconstructed tracts was verified. The novel methods allow for accurate in vivo muscle architectural measurement, which was demonstrated through the characterization of architectural properties in human forearm muscles.

Three in one - unusual palmaris longus muscle anatomical variation.

The palmaris longus muscle (PLM) is one of the most variable muscles in human body, pre-senting a wide range of morphological variants such as reversed course, biventer muscle, bi-furcated tendon or total agenesis. Their clinical impact is particularly important in diagnosis and treatment of carpal tunnel syndrome and reconstructive surgery. We present a case of PLM including a previously undescribed combination of variations. A routine dissection of male cadaver aged approximately 60 demonstrated a biventer muscle, with superior and inferior belly being interrupted by a long tendon. The inferior belly passed deep to the flexor retinaculum and its terminal tendon connected to flexor digitorum superfi-cialis tendon for 5th finger. The clinical importance of variations found have been described separately, including unsuita-bility of biventer muscles for tendon reconstruction and increased risk for developing carpal tunnel syndrome in patients with PLM tendon passing deep to the flexor retinaculum. In conclusion, as another variation of PLM is described, it is crucial to bear in mind the poten-tial morphological types of the muscle in diagnosis and treatment of patients, especially in surgery of the hand and forearm.

Characteristics of the Gantzer muscle and implications for its use as a tendon-graft source in upper extremity reconstruction

BackgroundThe Gantzer muscle is an anatomical variant muscle that functions in flexion of the volar forearm. The prevalence and laterality of this muscle has been studied more recently in the literature. This study aimed to determine the prevalence and size of this muscle and tendon. MethodsThis was an observational study done from September 2021 to January 2022 at the University of North Texas Health Science Center in Fort Worth, Texas. Cadaveric dissection was conducted in the Department of Physiology and Anatomy. 50 pairs for a total of 100 forearms were dissected bilaterally in cadavers comprising 17 females (34 %) and 33 males (66 %) to identify the Gantzer muscle. The mean age at death was 68.8 years of age (range 40–91 years). When present, the dimensions of each Gantzer tendon were measured in millimeters using digital calipers. As a study of cadaveric specimens, this study was exempt from Institutional Review Board (IRB) approval. ResultsThe Gantzer muscle was present in 62 of the 100 forearms (62 %). All 62 Gantzer muscles originated from flexor digitorum superficialis (FDS) (100 %). Of the 62 Gantzer muscles, 42 inserted distally into flexor pollicus longus (FPL) (72.5 %), while the remaining 17 muscles inserted distally into flexor digitorum profundus (FDP) (27.5 %). The tendons inserting into FDP had an average length of 65.495 mm, while those inserting into FPL had an average length of 16.353 mm (p = 0.002). The Gantzer muscle was present in 24 of the 33 male specimens (72.7 %) and 13 of the 17 female specimens (76.4 %). Of the 62 Gantzer muscles, 50 were present bilaterally (80.6 %), and there was no significant difference in bilateral occurrence between sexes (p = 0.189). ConclusionsOur results suggest that the Gantzer muscle may be of sufficient size and present commonly enough in the general population to be considered as an alternative graft source for certain upper extremity reconstruction procedures in place of, or in addition to, palmaris longus, extensor toe tendons, and other commonly used tendon grafts. In this study, when palmaris longus was absent in a specimen, a Gantzer muscle was likely present, and may provide surgeons an alternative tendon graft source in the upper extremity without requiring additional incisions in the lower extremity for alternative tendon graft sources. Further biomechanical testing of the Gantzer tendon with comparisons to other common tendon graft sources is warranted.

Impact of age and donor sites on bioactivities of tendon cells in autologous tenocyte implantation (OrthoATI™) for treatment of chronic tendinopathy

ObjectivesAutologous tenocyte implantation (OrthoATI™) therapy has demonstrated efficacy in treating patients with tendinopathy at various anatomical sites. This study evaluates the effect of patient age, gender, and tendon biopsy site on morphology, growth, and gene expression of autologous tendon cells used to treat chronic tendinopathy. MethodsPatients undergoing OrthoATI™ for tendinopathies between 2020 and 2022 were initially treated by biopsies taken from patella tendon (PT) or palmaris longus tendon (PL). The biopsies were sent to a Good Manufacturing Practice (GMP) cell laboratory where tendon cells were isolated, cultured, and expanded for four to six weeks. Cell morphology was assessed using phase contrast microscopy. Droplet digital PCR (ddPCR) was utilized for gene expression analysis. Dichotomous results were compared between groups using x2 or Fisher's exact tests with no adjustment for multiple comparisons. The nonparametric Mann–Whitney U and Kruskal–Wallis tests were utilized for the sex and age (<35y, 35-44y, 45-54y, >55y) analyses, respectively. All analyses were performed using IBM SPSS v27, and a two-tailed P-value of <0.05 was considered statistically significant. Results149 patients were included in the analysis. The PT was biopsied in 63 patients, and PL in 86 patients. There were no observer effects for age and gender between the PT and PL groups. There was no statistical significance between the PT and PL tendons for cell morphology, average cell population doubling time (PDT) (PT 83.9 vs PL 82.7 ​h, p ​= ​0.482), cellular yield (PT 16.2 vs PL 15.2 ​× ​106, p ​= ​0.099), and cell viability (PT 98.7 vs PL 99.0%, p ​= ​0.277). Additionally, ddPCR analyses showed no statistical significance found in tenogenic gene expression, including collagen type I (COL1, p ​= ​0.86), tenomodulin (TNMD, p ​= ​0.837) and scleraxis (SCX, p ​= ​0.331) between PT- and PL-derived tendon cells. An age stratification analysis found no effect on growth and gene expression. COL1 was found to be higher in males when compared to females (P ​< ​0.001), but otherwise no difference was seen in growth and gene expression in the gender analysis. No postbiopsy clinical complications were reported for either group. ConclusionThis study has shown that the growth and bioactivities of tendon cells from tendon biopsies for OrthoATI™ are not affected by tendon donor site and age. Level of evidenceIV.

SURGICAL TECHNIQUE FOR ANATOMICAL RE-CONSTRUCTION OF THE DISTAL RADIOULNAR LIGAMENTS IN CHRONIC TRAUMATIC INJURY OF THE TRIANGULAR FIBROCARTILAGE COMPLEX

Abstract-Injury to the triangular fibrocartilage complex (TFCC) can lead to instability of the distal radioulnar joint (DRUJ). In this article, we have presented a treatment method for patients with chronic traumatic TFCC injury. The surgical technique described here demonstrates anatomical reconstruction of the volar and dorsal distal radioulnar ligament using an autologous palmaris longus tendon graft.In the period 2014-2023, 22 patients with chronic traumatic injury to the triangular fibrocartilage complex, leading to instability of the DRUJ, were operated on in our clinic. The main parameters studied pre- and post-operatively were: degree of pain during active movements in the wrist joint and prono-supination of the forearm,range of active movements in the same joints, stability of DRUJ and grip strength relative to the contralateral limb.All 22 patients reported pain reduction with active wrist movements and forearm prono-supination. This surgical technique with anatomically based reconstruction of the distal volar and dorsal radioulnar ligament provides restoration of stability of the distal radioulnar joint and reduction of pain in patients with chronic injury to the triangular fibrocartilage complex.

Novel figure-of-eight reconstruction with free tendon graft for unrepairable collateral ligament of the thumb metacarpophalangeal joint

ObjectivesThis study aimed to report surgical technique and clinical outcomes for a novel figure-of-eight collateral ligament reconstruction technique using palmaris longus autograft for chronic irreparable collateral ligament injury of the thumb metacarpophalangeal joint. Material and methodsThe Jobe elbow collateral ligament reconstruction method was adapted for thumb metacarpophalangeal joint collateral ligament reconstruction. Sixteen reconstructions (7 ulnar collateral ligament, 9 radial collateral ligament) using palmaris longus autograft were reviewed retrospectively. Surgery was performed at a mean 12 months post-injury. All 16 patients were followed up for more than 1 year. Metacarpophalangeal joint radial and ulnar deviation, metacarpophalangeal and interphalangeal joint range of motion, key pinch and grip strength, Glickel functional grade and QuickDASH score were evaluated. ResultsPreoperative radial or ulnar deviation improved from 19.3° to 5.3° postoperatively. Metacarpophalangeal range of motion improved from 31.5° to 46.6°, and interphalangeal range of motion from 48.4° to 65.6°. Preoperative key pinch and grip strength were respectively 49% and 81% of contralateral values and improved to 82% and 87%. On Glickel grade, 9 cases were excellent and 7 good. ConclusionThe novel Jobe-like figure-of-eight reconstruction technique using palmaris longus graft was useful for reconstructing irreparable thumb metacarpophalangeal joint instability without an incision on the opposite side or an additional implant. Level of evidenceTherapeutic study, level IV.

The possible relationship between the palmaris longus and joint hypermobility.

The palmaris longus (PL) contributes to the palmar fascia, wrist flexion, hand muscle balance, and pinch strength. Also, PL is used as a graft source. So, PL's presence is helpful for joint stability and grafting. On the other hand, joint hypermobility (JH) is associated with many complaints and disorders. Considering the adverse effects of JH and benefit-based evolution, the genesis rather than agenesis of PL can be expected in JH. Herein, it was hypothesized that PL might be together with JH, and individuals with PL may have higher scores of JH than those without. Between June 2023 and October 2023, 200 participants (F/M: 1/1) were included in the study. The Schaeffer's test and the Beighton scores were used to assess PL and JH, respectively. The participants were divided into two bilateral groups according to the presence or absence of PL. Then, the groups were compared for demographics and Beighton scores. Subgroup analyses were also done by considering gender. No significant differences were found between PL (+) and PL (-) groups considering females+males in age (p=0.559), gender (p=0.517), weight (p=0.375), height (p=0.061), work status (p=0.229), Beighton score (p=0.893), and JH (p=1.0). No significant differences were found between PL (+) and PL (-) groups considering females only in age (p=0.871), weight (p=0.189), height (p=0.127), work status (p=0.200), Beighton score (p=0.727), and JH (p=1.0). No significant differences were found between PL (+) and PL (-) groups considering males only in age (p=0.370), weight (p=0.981), height (p=0.400), BMI (p=0.601), work status (p=0.145), Beighton score (p=0.757), and JH (p=1.0). According to the results of this study, no relationship was found between PL and JH. However, this is the first study on the topic and has some limitations.

Uncommon Anatomical Causes of Ulnar Compression: A Narrative Review.

Some patients develop ulnar nerve compression due to rare anatomical variations or malformations. The aims of this review are to provide a comprehensive overview of anatomical structures and variations that can cause ulnar nerve compression and to evaluate treatment options. Case reports and case series about rare cases of unusual ulnar nerve compression published from January 2000 until April 2022 were obtained from databases Embase, MEDLINE, and Web of Science. A total of 48 studies describing 64 patients were included in our study. The following structures have proven to cause ulnar nerve compression: anconeus epitrochlearis, accessory abductor digiti minimi, vascular anomalies, palmaris longus, fibrous bands, and flexor carpi ulnaris. All cases except one have had a surgical release of the ulnar nerve resulting in diminished symptoms or complete recovery at follow-up. In addition to considering common compression points, it is important to be aware that proximal compression symptoms, such as pain and a positive Tinel sign at the medial elbow, may be attributed to a hypertrophic AE or vascular anomaly. Distal compression symptoms encompass swelling, along with pain and a positive Tinel sign at the distal forearm. Various structures contributing to distal compression include an accessory abductor digiti minimi muscle, an accessory or anomalous palmaris longus muscle, or an accessory or hypertrophic flexor carpi ulnaris muscle. The occurrence of fibrous bands exhibits variability, manifesting in diverse locations across the arm.Level of Evidence: IV.

Multispectral Optoacoustic Tomography Enables In Vivo Anatomical and Functional Assessment of Human Tendons.

Tendon injuries resulting from accidents and aging are increasing globally. However, key tendon functional parameters such as microvascularity and oxygen perfusion remain inaccessible via the currently available clinical diagnostic tools, resulting in disagreements on optimal treatment options. Here, a new noninvasive method for anatomical and functional characterization of human tendons based on multispectral optoacoustic tomography (MSOT) is reported. Healthy subjects are investigated using a hand-held scanner delivering real-time volumetric images. Tendons in the wrist, ankle, and lower leg are imaged in the near-infrared optical spectrum to utilize endogenous contrast from Type I collagen. Morphology of the flexor carpi ulnaris, carpi radialis, palmaris longus, and Achilles tendons are reconstructed in full. The functional roles of the flexor digitorium longus, hallicus longus, and the tibialis posterior tendons have been visualized by dynamic tracking during toe extension-flexion motion. Furthermore, major vessels and microvasculature near the Achilles tendon are localized, and the global increase in oxygen saturation in response to targeted exercise is confirmed by perfusion studies. MSOT is shown to be a versatile tool capable of anatomical and functional tendon assessments. Future studies including abnormal subjects can validate the method as a viable noninvasive clinical tool for tendinopathy management and healing monitoring.