Distal Insertion Sites Research Articles

Changes in Pitch Velocity and Selection in Major League Baseball Pitchers Following the Ulnar Collateral Ligament Reconstruction.

The ulnar collateral ligament (UCL) is a soft-tissue stabilizer of the elbow, that is commonly injured among baseball pitchers due to excess valgus stress in overheadthrowing motions. The location of a UCL tear typically ranges from the central aspect of the ligamentto an avulsion-type injury at its proximal insertion site on the medialepicondyle of the humerus, or its distal insertion site on the ulna. The effect of UCL reconstruction on pitching performance has become a well-studied topic in medical literature. In our study, we aimed to identify general performance patterns amongst those having undergone UCL reconstruction surgery. Data for patients with UCL reconstruction performed between 2010 and 2020 were extracted from publicly available databases. Pitching data was extracted from Brooks Baseball, a publicly available database for Major League Baseball (MLB) player statistics. We identified patients who played at least one full season after surgery and rehabilitation. Patient characteristics were evaluated for intergroup differences. Of 109 patients with UCL reconstruction, 87 were included in the final analysis. Compared to the preoperative group, the average postoperative fastball usage rate was less despite there being an increase in the off-speed usage rate. Velocity analysis demonstrated shifts of less than 1% for all three pitch groups compared to preoperative velocity average values (all P-values <0.05). Earned Run Average (ERA)+demonstrates a decrease in the postoperative group; this finding was not significant (P=0.61). Patients treated surgically demonstrated a throwing tendency for theirsecondary and tertiary pitches and a decreased usage of fastballs. Further studies areneeded to explore the factors contributing to the change in pitching performance.

Ultrasonography in diagnosis of distal biceps tendinosis: A case series

Introduction: Biceps tendinosis, a milder form on the spectrum of biceps tendinopathy, is unusual at the distal insertion site. Patients with distal biceps tendinosis may experience pain and dysfunction which could inhibit their activities of daily living. Diagnosis of distal biceps tendinosis may be facilitated with ultrasonography (US), whose accuracy is increasingly recognised, while providing many benefits over other modalities, like magnetic resonance imaging (MRI). Case report: We report two cases of distal biceps tendinosis diagnosed by US with clinical details, imaging findings and patient management. Two patients present with elbow pain after nontraumatic activities. US revealed a thickened distal biceps tendon with mild heterogeneous hypoechogenicity without fibre disruption or retraction in both cases and evidence of hyperemia on Doppler with surrounding bursal fluid in case 2. Discussion: Tendinosis has variable aetiologies, but US commonly cannot differentiate among these; therefore, patient’s clinical history is the major component in determining the underlying cause. Chronic progression of tendon pathology leads to partial and full thickness tears. Tendinosis has a characteristic US appearance. US has many benefits and clinicians may use this modality to assess possible pathological structures with ease, convenience and efficiency compared with using MRI. Conclusion: Distal biceps tendinosis may present with clinical symptoms of pain and decreased activities of daily living, and may progress to more severe forms of tendinopathy. Early diagnosis is beneficial for the treatment outcomes of this condition. US can visualise distal biceps tendinosis with reliability, providing an alternative diagnostic technique with many benefits compared with MRI.

Optimal Distal Tendon Insertion Point for Elbow Flexion in Free-Functioning Gracilis Muscle Transfer for Panbrachial Plexus Injuries: A Cadaveric Study

Following pan-brachial plexus injuries, restoration of elbow flexion is widely accepted as the reconstructive priority. A gracilis free functioning muscle transfer (FFMT) can be used to restore elbow flexion alone with insertion into the biceps brachii (BIC) or brachioradialis (BRD) tendons or restore combined elbow and finger flexion with a more distal insertion into the flexor digitorum profundus (FDP) tendons. Using cadaveric experiments, we determined the peak instantaneous moment arm for each insertion option. Six simulated gracilis transfer surgeries were performed using both arms of three fresh-frozen full body cadaveric specimens (age: 79 + 10 years. 2 female). The gracilis muscles from both legs were harvested and transferred to the contralateral upper extremity. The elbow was manually moved through three flexion-extension cycles while the instantaneous moment arm was calculated from measurements of gracilis excursion and elbow joint angle for the three distal insertion sites. Peak instantaneous moment arm for all three insertions occurred at an elbow angle between 83° to 92° with a magnitude ranging from 33 mm to 54 mm. The more distal (FDP/BRD) insertions produced a significantly greater (∼1.5 times) peak elbow flexion instantaneous moment arm compared to the BIC insertion. Based on the instantaneous moment arm, the gracilis FFMT distal insertion locations could result in greater reconstructed elbow flexion strength. In addition, direct measurement of the shape and magnitude of the moment arm curve for differing insertion sites allows high resolution surgical planning and model testing. This study presents the first direct experimental quantification of the gracilis FFMT instantaneous moment arm. The experimental evidence supports the use of FDP/BRD insertion locations by providing a quantitative explanation for the increased elbow flexion torque observed clinically in patients with a gracilis FFMT and distal FDP insertion.

Discovery of a Bilateral Fibulocalcaneus Externum Invertus Muscle: A Novel Fibularis Quartus Variant

The fibularis (peroneus) quartus is a variant muscle found within the lateral leg compartment in ~11.5% of cadaveric specimens, though recent studies have shown a higher prevalence of ~20.9 – 21.9%. The proximal muscular attachments can originate from the fibula, fibularis brevis, fibularis longus, and/or the intermuscular septi that form the boundaries of the lateral leg compartment, but it then descends to reside posterior to the lateral malleolus of the fibula. The distal attachment of the fibularis quartus varies greatly, and fibularis quartus muscular variants are often named according to location of its distal attachment. The most common distal insertion site of a fibularis quartus muscle is the lateral surface of the calcaneus into either the fibular trochlea or the retrotrochlear eminence. Therefore, this variant of the fibularis quartus inserting into the lateral surface of the calcaneus is called the fibulocalcaneus externum. During routine cadaveric dissection of a 79‐year‐old Caucasian male, a rare and novel variation of the fibularis quartus muscle was discovered. Although this variant is seen arising from the fibula, fibularis brevis, and the posterior intermuscular septum, descending posterior to the lateral malleolus, and attaching distally to the lateral surface of the calcaneus, it is unique in that the muscle is inverted, with the tendonous part being more proximal and the muscular portion arising distally. This novel muscle was found unilaterally in the left leg via dissection initially with its distal head inserting on the fibular trochlea of the calcaneus, but ultrasonographic imaging verified its bilateral presence. The subsequent dissection of the right leg revealed a similar inverted muscle, but this variation split into two distal muscle bellies inserting into the retrotrochlear eminence posteriorly and the fibular trochlear anteriorly. Given its anatomy, we have named this rare fibularis quartus variant the fibulocalcaneus externum invertus muscle. Like most fibularis quartus variants, the fibulocalcaneus externum invertus muscle can cause ankle instability, ankle locking, chronic lateral ankle pain, and peroneal compartment syndrome, especially due to acting as a space‐occupying lesion within the superior peroneal tunnel due to its distal muscle belly/bellies. While it is unknown if this person had any clinical signs and/or symptoms, clinicians, surgeons, and/or radiologists should be aware of the fibulocalcaneus externum invertus when assessing radiological imaging or preparing for ankle surgeries in and around the lateral leg compartment.

Prevalence and morphometric characteristics of the anterolateral ligament of the knee in a sample of Colombian human cadaversand morphometric characteristics of the anterolateral ligament of the knee in a sample of Colombian human cadavers

Introduction: Even though the anatomy of the knee and its ligaments are well characterized in the literature, several studies have found new structures associated with this joint, such as the anterolateral ligament (ALL) of the knee. The prevalence of this ligament varies significantly across the globe, and studies addressing this topic in the Colombian population are scarce. Objective: To determine the prevalence of the ALL and its morphometric characteristics in a sample of Colombian human cadavers. Materials and methods: Cross-sectional study in which the knee joints of 15 human cadavers were dissected and analyzed. In order to preserve the integrity of anatomical structures such as ligaments and tendons, specimens should not have undergone previous dissections, so only 29 knees were included for analysis. The presence of the ligament was confirmed, and the proximal and distal insertion site, as well as its length and width, were established through dissection. Results: The prevalence of ALL was 24.13%, as it was identified in 7 of the 29 dissected knees (4 left and 3 right knees). The average length and width of the ALLs found were 37.5mm (range: 24-52.4mm) and 3.9mm (range: 2.6-6mm), respectively. Conclusions: This study allowed confirming the presence of the ALL in the Colombian population, although with a lower prevalence than that described in countries such as France, India, China, USA, and Brazil. In turn, its morphometric characteristics were similar to those reported worldwide, since the average length and width found here are consistent with those described in the literature.

Which Approach Is Most Optimal for Needle Electromyographic Examination of the Biceps Femoris Short Head: Medial or Lateral?

ObjectiveTo investigate the anatomical characteristics of the biceps femoris short head (BS) and determine the optimal needle placement for BS examination.MethodsTwenty-one lower limbs were dissected. The distances from the medial and lateral margins of the biceps femoris long head (BL) tendon to the common fibular nerve (CFN) (M_CFN_VD and L_CFN_VD, respectively) and the distance from the lateral margin of the BL tendon to the lateral margin of the BS (L_BS_HD) were measured 5 cm proximal to the tip of the fibular head (P1), four fingerbreadths proximal to the tip of the fibular head (P2), and at the upper apex of the popliteal fossa (P3).ResultsThe BS was located lateral to the BL tendon. The CFN was located along the medial margin of the BL tendon. The median values were 2.0 (P1), 3.0 (P2), and 0 mm (P3) for M_CFN_VD; and 17.4 (P1), 20.2 (P2), and 21.8 mm (P3) for L_CFN_VD; and 8.1 (P1), 8.8 (P2), and 13.0 mm (P3) for L_BS_VD.ConclusionThe lateral approach to the BL tendon was safer than the medial approach for examining the BS. Amore proximal insertion site around the upper apex of the popliteal fossa was more accurate than the distal insertion site. In this study, we propose a safer and more accurate approach for electromyography of the BS.

Partial Distal Biceps Avulsion Results in a Significant Loss of Supination Force.

Partial avulsions of the short and/or long head of the distal biceps tendon cause pain and loss of strength. The goal of the present study was to quantify the loss of supination and flexion strength following a series of surgical releases designed to simulate partial and complete short and long head traumatic avulsions. Mechanical testing was performed to measure supination moment arms and flexion force efficiency on 18 adult fresh-frozen specimens in pronation, neutral, and supination. The distal biceps footprint length was divided into 4 equal segments. In 9 specimens (the distal-first group), the tendon was partially cut starting distally by releasing 25%, 50%, and 75% of the insertion site. In the other 9 specimens (the proximal-first group), the releases started proximally. Mechanical testing was performed before and after each release. Significant decreases in the supination moment arm occurred after a 75% release in the distal-first release group; the decrease was 24% in pronation (p = 0.003) and 10% in neutral (p = 0.043). No significant differences in the supination moment arm (p ≥ 0.079) or in flexion force efficiency (p ≥ 0.058) occurred in the proximal-first group. A simulated complete short head avulsion significantly decreased the supination moment arm and therefore supination strength. A mechanical case can be made for repair of partial distal biceps tendon avulsions when the rupture involves ≥75% of the distal insertion site.

Pollicization of Biphalangeal Index Finger for Type IV Thumb Hypoplasia: A Case Report Describing Preoperative Planning, Intraoperative Decision-Making, and Technical Modifications

Index finger (IF) pollicization is the standard treatment for severe congenital thumb hypoplasia. The procedure requires a supple and anatomically normal IF. No guidelines exist for IF pollicization in patients who have concomitantly underdeveloped IF, specifically when the digit has only 2 phalanges and 1 interphalangeal joint. We present a case of a 20-month-old boy with congenital type IV thumb hypoplasia who also had biphalangeal IF. We proposed an IF pollicization operation that required significant modifications to the traditional procedure. Preoperative planning and intraoperative execution are described. The modifications to the traditional procedure included: (1) removal of proximal third of IF metacarpal; (2) creation of a de novo thumb carpometacarpal (CMC) joint by fibrous union whereby the IF CMC joint cartilaginous components are maintained and the remaining distal IF metacarpal is translocated down and secured to this cartilage (in contrast to the traditional use of IF metacarpophalangeal joint as a de novo thumb CMC joint); (3) preservation of IF joints at their "natural" position and function; (4) maintenance of intrinsic muscles at their original distal insertion sites; and (5) important adjustments to skin incision. Pollicization of biphalangeal IF can be executed in a safe and efficient manner. Early recovery has shown promising signs. Long-term results, including the de novo thumb CMC joint function, remain to be evaluated.

Clinical significance of the distal insertion sites of the semimembranosus tendons

Clinical significance of the distal insertion sites of the semimembranosus tendons

ASSESSMENT OF THE REGENERATION CAPACITY OF SEMITENDINOSUS AND GRACILIS TENDONS

ABSTRACTObjectives:To evaluate the regenerative capacity of gracilis (G) and semitendinosus (ST) tendons, to examine the sensitivity and specificity of signs and symptoms in the assessment of hamstring tendons, and to assess the thickness and insertion site of regenerated tendons.Methods:Thirty sequential knees were subjected to anterior cruciate ligament reconstruction with semitendinosus and gracilis tendons. After surgery, the patients were followed up clinically with physical examination and magnetic resonance imaging (MRI).Results:Overall, 36.66% of the tendons were visible on MRI, whereas 83.33% were palpable. On MRI, the distal insertion site of the regenerated semitendinosus tendon was visible proximal to the landmark of the medial femoral condyle in 28%, at the same level in 16%, and distally in 56% of the cases. Gracilis tendon insertion was visible proximally in 36.66% of cases, at the same level in 10%, and distally in 53.33%. Eleven knees exhibited complete regeneration.Conclusion:Partial or total regeneration of the ST and G tendons was apparent on MRI. Palpation is effective for evaluating regeneration of the ST and G tendons; however, MRI is still the gold standard. ST and G tendons regenerated completely in only a small percentage of patients, limiting reuse as a graft in cases with new ligament injuries of the knee. Level of Evidence II, Prospective comparative study.

Electrocardiographic and electrophysiologic differentiation between atriofascicular, long atrioventricular, and short atrioventricular decrementally conducting accessory pathways.

We aimed to examine the electrocardiographic and electrophysiologic characteristics of anterograde-conducting decremental accessory pathways (DAP) and to identify surrogate criteria to distinguish short atrioventricular (SAV) DAP from atriofascicular (AF) AP and long atrioventricular (LAV) DAP. We identified all patients with DAPs and analysed electrocardiographic and electrophysiologic characteristics. Distal insertion sites were examined using existing criteria, including V-H interval, ventricular activation at the right ventricular apex, and around tricuspid annulus during antidromic atrioventricular re-entrant tachycardia (A-AVRT) or complete pre-excitation and evaluated the AV node-like properties according to the response to adenosine and radiofrequency ablation. Out of 45 patients with DAPs, 28 (62.2%) had SAV-DAP (13 with definite AF-AP, 2 with definite LAV-DAP, 2 indeterminate). In all, 50% of SAV-DAPs and 53.3% of AF-AP/LAV-DAPs had 'rS' pattern in lead III. Longer QRS duration (159.9 ± 17.4 ms vs. 139.2 ± 14.3 ms, P < 0.0001) during full pre-excitation or A-AVRT differentiated SAV-DAP from AF-AP. The QRS-V(His) interval was longer for those with SAV-DAP compared vs. AF-AP/LAV-DAP (45.3 ± 2.4 ms vs. 22.9 ± 2.5 ms, P < 0.0001) and a cut-off value of 33.0 ms differentiated the two (sensitivity 81.3%, specificity 87.5%). The majority of the SAV-DAPs are located at the TA free wall. An 'rS' pattern in lead III is frequently seen in SAV-DAP as well as AF-AP/LAV-DAPs. Measuring the QRS-V(His) interval would be helpful to distinguish SAV-DAP from AF-AP/LAV-DAP.

Conservative Management after Intraoperative Over-Release of the Medial Collateral Ligament from its Tibial Insertion Site in Patients Undergoing Total Knee Arthroplasty.

During varus deformity correction in a patient undergoing total knee arthroplasty (TKA), the medial collateral ligament (MCL) could get completely detached from its distal insertion site. Our aim was to evaluate the (1) mid-term clinical outcome and implant survival after conservative treatment in patients with intraoperatively over-released MCL and (2) preoperative risk factors for MCL over-release. A retrospective study was conducted on patients who had undergone a primary TKA between 2001 and 2006. The number of knees with intraoperative MCL over-release (over-released group) was 47 (40 patients); we compared these with the knees that had intact MCL (intact group, 502 knees). Simple anchoring of MCL was performed with no additional protection. The postoperative clinical outcome and implant survival were compared. Risk factors for MCL over-release were identified using multivariate analysis. The average follow-up period was 7.5 years. The mean Knee Society score of the over-released group improved from 23.3 to 92.7 and it was not significantly different from the intact group. Three cases of aseptic loosening occurred in the over-released group and 19 in the intact group (p = 0.423). The survival rates of the implant were 94.4% and 96.1%, respectively, at 13 years postoperatively. Multivariate analysis showed preoperative femoral-tibial angle as the only risk factor for over-release. This study showed that even MCL was over-released inadvertently, but it did not affect the clinical outcome. Preoperative femoral-tibial angle was the only predictable risk factor for MCL over-release.

The Anatomy of the Articularis Genus Muscle and Its Relation to the Extensor Apparatus of the Knee.

Background:The anatomy of the articularis genus muscle has prompted speculation that it elevates the suprapatellar bursa during extension of the knee joint. However, its architectural parameters indicate that this muscle is not capable of generating enough force to fulfill this function. The purpose of the present study was to investigate the anatomy of the articularis genus, with special emphasis on its relationship with the adjacent vastus intermedius and vastus medialis muscles.Methods:The articularis genus muscle was investigated in 18 human cadaveric lower limbs with use of macrodissection techniques. All components of the quadriceps muscle group were traced from origin to insertion, and their affiliations were determined. Six limbs were cut transversely in the middle third of the thigh. The modes of origin and insertion of the articularis genus, its nerve supply, and its connections with the vastus intermedius and vastus medialis were studied.Results:The muscle bundles of the articularis genus were organized into 3 main layers: superficial, intermediate, and deep. The bundles of the superficial layer and, in 60% of the specimens, the bundles of the intermediate layer originated from both the vastus intermedius and the anterior and anterolateral surfaces of the femur. The bundles of the deep layer and, in 40% of the specimens, the bundles of the intermediate layer arose solely from the anterior surface of the femur. The distal insertion sites included different levels of the suprapatellar bursa and the joint capsule. A number of connections between the articularis genus and the vastus intermedius were found. While the vastus medialis inserted into the whole length of the vastus intermedius aponeurosis, it included muscle fibers of the articularis genus, building an intricate muscle system supplied by nerve branches of the same medial deep division of the femoral nerve.Conclusions:The articularis genus, vastus medialis, and vastus intermedius have a complex, interacting architecture, suggesting that the articularis genus most likely does not act as an independent muscle. With support of the vastus intermedius and vastus medialis, the articularis genus might be able to function as a retractor of the suprapatellar bursa. The finding of likely interplay between the articularis genus, vastus intermedius, and vastus medialis is supported by their concurrent innervation.Clinical Relevance:The association between the articularis genus, vastus medialis, and vastus intermedius may be more complex than previously believed, and this close anatomical connection could have functional implications for knee surgery. Dysfunction, scarring, or postoperative arthrofibrosis of the sophisticated interactive mechanism needs further investigation.

Safety Window for the Volar Needle Approach for Examination of the Pronator Quadratus Using Ultrasonography

ObjectivesTo investigate pronator quadratus (PQ) anatomy and determine the proper volar needle insertion point based on landmarks, the tip of the ulnar styloid (an imaginary vertical line passing the tip of the ulnar styloid process [U line]), and the ulnar margin of the palmaris longus tendon (uPL) using ultrasonography. DesignDescriptive study. SettingDepartment of physical medicine and rehabilitation. ParticipantsParticipants between 20 and 60 years without any diseases. (N=25; 13 men, 12 women; 50 forearms). InterventionsUltrasonography. Main Outcome MeasuresThe proximal and distal volar surface points of origin, the proximal and distal insertion sites, and the midpoint of the PQ (PQ_M) were determined. The distance of each of the PQ surface indices from the U line was measured, and the probe was positioned at the level of PQ_M parallel to the U line. The relative distances from the vertical surface points of the median nerve and ulnar artery to the uPL were measured. ResultsThe mean age and body mass index were 32.7±10.4 years and 21.98±2.83kg/m2. The PQ_M was located at a mean distance of 2.63±0.35cm proximal from the U line (men 2.79±0.37cm and women 2.45±0.21cm; P<.05). The mean safety window for the volar approach was 0.72±1.8cm toward the radial side and 1.51±0.30cm toward the ulnar side from the uPL. The PQ was at a mean depth of 1.30±0.19cm from the skin and had a mean thickness of 1.19±0.24cm at the level of PQ_M. The distance between the U line and the proximal edge of the PQ, as well as the PQ thickness, was greater in men than in women. ConclusionsThe volar approach for needle electromyographic examination of the PQ can be performed precisely and safely.

MRI features of the anterolateral ligament of the knee.

Evaluate the visibility and describe the anatomical features of the anterolateral ligament of the knee using MRI. Magnetic resonance imaging examinations of the knee were independently reviewed by two musculoskeletal radiologists and assessed for the visibility of the anterolateral ligament under direct cross-referencing of axial and coronal images as complete, partial, or non-visible. Distal insertion site (tibial, meniscal), distance to lateral tibial plateau, measurements (length, width, thickness), and associated imaging findings were also tabulated. Clinical and surgical records were also reviewed. Seventy MRI scans from 60 consecutive subjects were included in the study. Mean age was 40 years, body mass 74.9 kg, and height 1.72 m. The subject population was 53% male, most of the knees were from the left side (51%), and chronic pain was the main clinical symptom (40%). Nine knees (13 %) had undergone previous surgery. The anterolateral ligament was identified in 51% of the knees: completely visible in 11% and partially visible in 40%. In all visible cases, the distal insertion site was identified on the tibia, with a mean distance of 5.7 mm to the plateau. A completely visible ligament had a mean length of 33.2 mm, width of 5.6 mm, and thickness of 1.9 mm [corrected]. Inter-observer agreement for ligament presence was significant (κ = 0.7). Statistical analyses showed a trend to be more visible in men, with a longer length compared with women. Magnetic resonance imaging clearly identifies the anterolateral ligament of the knee in slightly more than half of cases, being partially visible in most of them. In all cases, a tibial insertion is characterized.

The transverse carpal ligament: anatomy and clinical implications.

The anatomical characteristics of the transverse carpal ligament (TCL) have recently been further clarified. Its bony insertion sites proximally to the scaphoid and pisiform are more round, whereas the distal insertion sites to the trapezium and hamate are more oblong, with reproducible areas of insertion. The thickness of the TCL varies along the path of the median nerve, with the thickest portions distal ulnarly and proximal radially. The predominant fiber orientation is transverse. This more detailed understanding of the anatomy of the TCL may enable more novel treatments of carpal tunnel syndrome.

The anatomy of the external branch of the superior laryngeal nerve in Koreans

Preservation of the external branch of the superior laryngeal nerve (EBSLN) during thyroidectomy is important because its injury may lead to frequent occurrence of vocal fatigue and the inability to perform superenergetic phonation. Most studies on the anatomy of EBSLN have been performed in Western countries and, thus, have some limitations in their application to Koreans. We explored the anatomy of EBSLNs using intraoperative neuromonitoring (IONM) in Korean adults. Between August 2011 and December 2011, 50 patients underwent thyroidectomy at Korea University, Anam Hospital in Seoul, Korea. IONM was performed with the NIM response 3.0 system. Forty-two total thyroidectomies and eight lobectomies were performed with IONM and 92 EBSLNs were evaluated. Type I EBSLN was observed in 15 of the 92 nerves (16.3%), type IIa EBSLN was noted in 52 (56.5%) and type IIb EBSLN was noted in 25 (27.2%). Patients with types IIa and IIb were at higher risk of injuries and these types were more frequently observed (83.7%) compared with previous Western studies. We found that 35.9% of distal insertion sites of EBSLNs were located within 1cm of the center of the cricoid cartilage. Surgeons should pay close attention to preserving the EBSLN during thyroidectomy in Korean patients because their EBSLNs are more frequently located beneath the superior thyroid vessels.