Deep learning model shows promise for detecting and grading sesamoiditis in horse radiographs.

OBJECTIVE: The objective of this study was to develop a robust machine-learning approach for efficient detection and grading of sesamoiditis in horses using radiographs, specifically in data-limited conditions. SAMPLE: A dataset of 255 dorsolateral-palmaromedial oblique (DLPMO) and dorsomedial-palmarolateral oblique (DMPLO) equine radiographs were retrospectively acquired from Hagyard Equine Medical Institute. These images were anonymized and classified into 3 categories of sesamoiditis severity (normal, mild, and moderate). METHODS: This study was conducted from February 1, 2023, to August 31, 2023. Two RetinaNet models were used in a cascaded manner, with a self-attention module incorporated into the second RetinaNet's classification subnetwork. The first RetinaNet localized the sesamoid bone in the radiographs, while the second RetinaNet graded the severity of sesamoiditis based on the localized region. Model performance was evaluated using the confusion matrix and average precision (AP). RESULTS: The proposed model demonstrated a promising classification performance with 92.7% accuracy, surpassing the base RetinaNet model. It achieved a mean average precision (mAP) of 81.8%, indicating superior object detection ability. Notably, performance metrics for each severity category showed significant improvement. CLINICAL RELEVANCE: The proposed deep learning-based method can accurately localize the position of sesamoid bones and grade the severity of sesamoiditis on equine radiographs, providing corresponding confidence scores. This approach has the potential to be deployed in a clinical environment, improving the diagnostic interpretation of metacarpophalangeal (fetlock) joint radiographs in horses. Furthermore, by expanding the training dataset, the model may learn to assist in the diagnosis of pathologies in other skeletal regions of the horse.

Common fibular nerve palsy due to the Fabella: A review.

One of the most common nerve palsies - common fibular nerve palsy - can be caused by the variant small sesamoid bone in the posterolateral compartment of the knee joint known as the fabella. We compared and reviewed all reported cases of common fibular nerve palsy due to fabellae in the English literature. Compression can develop spontaneously or post-surgically (total knee arthroplasty). Symptoms progress rapidly to complete foot drop. Among all the cases reviewed, 68.42% were males with a median age of 39.39 years. Fabella compression was more common in the left common fibular nerve (CFN) (63.16%). Both big (23 × 20 × 16 mm) and small (5 × 5 mm) fabellae can be responsible for compression. While diagnosis can be problematic, the treatment (either surgical fabellectomy or conservative) is relatively easy and brings quick improvement.

The trabecular architecture of the popliteal sesamoid bone (cyamella) from a New Zealand white rabbit (Oryctolagus cuniculus).

Sesamoid bones are ossified structures that are embedded in tendons near articulation. They consist of an inner trabecular bone architecture surrounded by a thin cortical shell. While the formation of sesamoid bones is probably mainly controlled by genetic factors, the proper development and mineralization of a sesamoid bone depends also on mechanical stimulation. While most sesamoid bones are not loaded directly by other bones during locomotion, they still experience forces directed from the tendon in which they are embedded. In cases when the sesamoid bone is experiencing forces only from a single tendon, such as the cyamella in the rabbit, this may give us a tool to study bone functional adaptation in a relatively simple loading setting. This study investigates the internal trabecular architecture of the popliteal sesamoid bone (cyamellae) in New Zealand white (NZW) rabbits (Oryctolagus cuniculus). Five hind limbs of NZW rabbits were micro-computed tomography scanned and the cortical and trabecular architectures of the cyamellae were evaluated. The results revealed that similar to the patella, the cyamella has a thin cortex and a high trabecular bone volume fraction (BV/TV), which is derived mostly from the high trabecular thickness (Tb.Th). Trabecular BV/TV and Tb.Th were not distributed homogeneously, but they were lower at the periphery and higher closer to the proximal and middle of the cyamella, near the musculotendinous junction. The results also demonstrated that trabeculae tend to align along two recognizable orientations, one with the direction of tensile stresses, in line with the popliteal tendon, and the second bridging the narrow space between the cranial and caudal cortical faces of the bone.

Fracture of the fabella with radiologic and MRI.

The fabella is an inconstant sesamoid bone. A handful of cases have been reported so far describing fabella fracture, usually involving high energy mechanism or stress fractures after total knee arthroplasty. This paper presents a fabella fracture in a man in his 40s after suffering a car crash, the clinical and radiographic presentation, treatment and complete recovery at 4-months follow-up.

The morphology of cyamella and its prevalence in Turkish society.

OBJECTIVE: The aim of this study is to determine the prevalence and morphometry of cyamella, one of the sesamoid bones around the knee joint. PATIENTS AND METHODS: In this retrospective study, a total of 9,500 plain/digital radiographs of 6,500 patients over the age of 18 who applied to Elazig Fethi Sekin City Hospital between January 2021 and January 2022 were examined. RESULTS: Examinations revealed cyamella in a total of 76 (0.8%) knees in the direct X-ray images of 49 (0.75%) patients. Eighteen (36.74%) of the patients with the presence of cyamella were males, and 31 (63.26%) were females. The mean age of the patients with cyamella was 50.9±12.9. Twenty-seven (55.1%) of the 49 cyamella were bilateral; seven (14.3%) were in the right knee, and 15 (30.6%) were in the left knee. The comparison of cyamella sizes between genders revealed a statistically significant difference in the transverse measurements only (p=0.015) in the right knee, while a statistically significant difference was found in all 3 parameters (p=0.032 for thickness; p=0.04 for transverse; p=0.026 for length) in the left knee. CONCLUSIONS: We believe that sufficient knowledge regarding the prevalence and distribution of cyamella in patients presenting with the complaint of knee pain and its differentiation from fabella, another sesamoid bone in the same region, as well as other anatomical structures, will aid an early and accurate diagnosis.

Partial Excision of a Tibial Sesamoid Fracture Nonunion in a Patient with Congenital Absence of Fibular Sesamoid: A Case Study.

BACKGROUND: Hallucal sesamoid injuries occur in approximately 5% to 10% of foot and ankle injuries. Most cases can be treated conservatively. However, when nonoperative management fails, surgical intervention is warranted. METHODS: The present case involved a 17-year-old female high school senior who presented to the clinic with right hallux pain. Radiographs were obtained and revealed congenital absence of the fibular sesamoid and evidence of a minimally displaced avulsion fracture involving the proximal medial tibial sesamoid. Treatment was complicated by the congenital absence of the fibular sesamoid and by a high activity level. RESULTS: After conservative treatment failure, the patient underwent partial excision of her tibial sesamoid. She was followed for 1.5 years after initial presentation to our clinic. The patient was able to return to daily activities; however, she was not able to return to softball competitively due to pain. CONCLUSIONS: We hypothesize she was unable to return to softball because the absence of a sesamoid can decrease push-off strength. We recommend that providers treating athletes educate their patients on the possible loss of strength and take this into account when creating a treatment plan.

A modified minimally invasive osteotomy for hallux valgus enables reduction of malpositioned sesamoid bones.

BACKGROUND: The current minimally invasive distal metatarsal osteotomy for hallux valgus (HV) is V-shaped, which prevents the correction of the rotational metatarsal head deformity and reduction of the sesamoid bones. We sought to determine the optimal method for sesamoid bone reduction during HV surgery. METHODS: We reviewed the medical records of 53 patients who underwent HV surgery between 2017 and 2019 using one of three techniques: open chevron osteotomy (n = 19), minimally invasive V-shaped osteotomy (n = 18), and a modified straight minimally invasive osteotomy (n = 16). The sesamoid position was graded using the Hardy and Clapham method on weight-bearing radiographs. RESULTS: When compared to open chevron and V-shaped osteotomies, the modified osteotomy resulted in significantly lower postoperative sesamoid position scores (3.74 ± 1.48, 4.61 ± 1.09, and 1.44 ± 0.81, respectively, P < 0.001). Furthermore, the mean change in postoperative sesamoid position score was greater (P < 0.001). CONCLUSION: The modified minimally invasive osteotomy was superior to the other two techniques in correcting HV deformity in all planes, including sesamoid reduction.

An overview of the osseous palmar sesamoid in Anura, with the particular case of some Rhinella species.

Background: Sesamoids are generally regarded as structures that are not part of the tetrapod body plan. The presence of a palmar sesamoid is assumed to serve as a distribution point for the forces of the flexor digitorum communis muscle to the flexor tendons of the digits, which are embedded in the flexor plate. It has been considered that the palmar sesamoid is present in most anuran groups, and it has been suggested that it acts by inhibiting the closing of the palm, preventing grasping. Typical arboreal anuran groups lack a palmar sesamoid and flexor plate, a pattern shared with other tetrapod groups, which can retain a reduced sesamoid and flexor plate. We focus on the anatomical structure of the Rhinella group, which includes species that present an osseous palmar sesamoid and climb bushes or trees to avoid depredation or escape dangerous situations, and can exhibit scansorial and arboreal behaviors. We also add data on the bony sesamoids of 170 anuran species to study the anatomy and evolution of the osseous palmar sesamoid within this amphibian group. Our objective is to bring an overview of the osseous palmar sesamoid in anurans, unveiling the relationship between this element of the manus, its phylogeny, and the anuran habitat use. Methods: Skeletal whole-mount specimens of Rhinella were cleared and double-dyed to describe the sesamoid anatomy and related tissues. We review and describe the palmar sesamoid of 170 anuran species from CT images downloaded from Morphosource.org, representing almost all Anuran families. We performed an standard ancestral state reconstruction by optimizing two selected characters (osseous palmar sesamoid presence, distal carpal palmar surface) along with the habitat use of the sampled taxa, using parsimony with Mesquite 3.7. Results: Our primary finding is that sesamoid optimization in the anuran phylogeny revealed that its presence is associated with certain clades and not as widespread as previously anticipated. Additionally, we will also be delving into other important outcomes of our study that are relevant to those working in the field of anuran sesamoids. The osseous palmar sesamoid is present in the clade Bufonidae-Dendrobatidae-Leptodactylidae-Brachicephalidae that we named as PS clade, and also in the archeobatrachian pelobatoid Leptobranchium, all strongly terrestrial and burrowing species, though with exceptions. The osseous palmar sesamoid is always present in Bufonidae, but varies in form and size, depending on the mode that they use their manus, such as in the Rhinella margaritifera which has a cylindrical one and also grasping abilities that involve closing the manus. The scattered presence of the bony palmar sesamoid among anuran clades raises the question whether this sesamoid can be present with a different tissular composition in other groups.

Correlations of Sesamoid Bone Subluxation with the Radiologic Measures of Hallux Valgus and Its Clinical Implications.

Background and Objectives: Hallux valgus is one of the most common chronic foot complaints, with prevalences of over 23% in adults and up to 35.7% in older adults. However, the prevalence is only 3.5% in adolescents. The pathological causes and pathophysiology of hallux valgus are well-known in various studies and reports. A change in the position of the sesamoid bone under the metatarsal bone of the first toe is known to be the cause of the initial pathophysiology. Purpose: The relationships between the changes in the location of the sesamoid bone and each radiologically measured angle and joint congruency in the hallux valgus remain as yet unknown. Therefore, this study investigated the relationships of sesamoid bone subluxation with the hallux valgus angle, intermetatarsal angle, and metatarsophalangeal joint congruency in hallux valgus patients. The goal is to know the hallux valgus angle, the intermetatarsal angle, and metatarsophalangeal joint congruency's correlation with hallux valgus severity and prognosis by revealing the relationship between each measured value and sesamoid bone subluxation. Materials and Methods: We reviewed 205 hallux valgus patients who underwent radiographic evaluation and subsequent hallux valgus correction surgery in our orthopedic clinic between March 2015 and February 2020. Sesamoid subluxation was assessed using a new five-grade scale on foot radiographs, and other radiologic measurements were assessed, such as hallux valgus angle, the intermetatarsal angle, distal metatarsal articular angle, joint congruency, etc. Conclusions: Measurements of the hallux valgus angle, interphalangeal angle, and joint congruency exhibited high interobserver and intraobserver reliabilities in this study. They also showed correlations with sesamoid subluxation grade.

New insight into the morphological characteristics of patella cubiti.

Accessory bones in the elbow region are rare anatomical variations with important clinical significance as they can be misdiagnosed as pathological lesions. Usually, they are asymptomatic and found incidentally during X-ray examination in the context of trauma. Although these bones have been previously described, their development is not fully understood. The present case provides complex macroscopic, X-ray and histological descriptions of a sesamoid bone in the posterior region of the elbow-patella cubiti and the related surrounding structures. Moreover, this report indicates the presence of a well-defined syndesmosis between patella cubiti and the proximal ulna.

Patella cubiti - a continuing etiological mystery / Patella cubiti: un misterio etiológico continuo

SUMMARY: A sesamoid bone in the elbow joint is a rare anatomical variation described as a Patella cubiti. Although this variation has been known for centuries its exact etiology is still unclear. Congenital, developmental, and traumatic hypotheses have been proposed. It seldom causes clinical manifestations than elbow stiffness or hypomobility. Herein, we present a case of a 31-year-old patient admitted to our department with complaints of swelling and erythema in the right elbow. An X-ray image revealed a triangular accessory bone with rounded edges, which was diagnosed as a Patella cubiti in combination with olecranon bursitis. Knowledge of this rare elbow abnormality is paramount for orthopedic surgeons and roentgenologists in their daily medical practice.

Un hueso sesamoideo en la articulación del codo es una rara variación anatómica descrita como Patella cubiti. Aunque esta variación se conoce desde hace siglos, su etiología exacta aún no está clara. Se han propuesto hipótesis congénitas, de desarrollo y traumáticas. Rara vez causa manifestaciones clínicas que no sean rigidez o hipomovilidad del codo. Presentamos el caso de un paciente de 31 años que ingresó en nuestro servicio por presentar tumefacción y eritema en el codo derecho. Una imagen de rayos X reveló un hueso accesorio triangular con márgenes redondeados, que se diagnosticó como una Patella cubiti en combinación con bursitis del olécranon. El conocimiento de esta rara anomalía del codo es fundamental para los cirujanos ortopédicos y los médicos radiólogos en su práctica médica diaria.

Training drives turnover rates in racehorse proximal sesamoid bones.

Focal bone lesions are often found prior to clinically relevant stress-fractures. Lesions are characterized by low bone volume fraction, low mineral density, and high levels of microdamage and are hypothesized to develop when bone tissue cannot sufficiently respond to damaging loading. It is difficult to determine how exercise drives the formation of these lesions because bone responds to mechanical loading and repairs damage. In this study, we derive steady-state rate constants for a compartment model of bone turnover using morphometric data from fractured and non-fractured racehorse proximal sesamoid bones (PSBs) and relate rate constants to racing-speed exercise data. Fractured PSBs had a subchondral focus of bone turnover and microdamage typical of lesions that develop prior to fracture. We determined steady-state model rate constants at the lesion site and an internal region without microdamage using bone volume fraction, tissue mineral density, and microdamage area fraction measurements. The derived undamaged bone resorption rate, damage formation rate, and osteoid formation rate had significant robust regression relationships to exercise intensity (rate) variables, layup (time out of exercise), and exercise 2-10 months before death. However, the direction of these relationships varied between the damaged (lesion) and non-damaged regions, reflecting that the biological response to damaging-loading differs from the response to non-damaging loading.

The prevalence of fabella and its relationship with the lateral posterior condylar offset and lateral posterior tibial slope values.

OBJECTIVES: This study aims to analyze whether the lateral posterior condylar offset (LPCO) and lateral posterior tibial slope (LPTS) values are associated with the presence of fabella by evaluating the frequency of fabella, its location, and whether it is bilateral and the relationship of the fabella with age, sex, and the presence of osteoarthritis. PATIENTS AND METHODS: Between January 2016 and December 2020, computed tomography (CT) scans including 1,952 knee regions of 1,220 patients (861 males, 359 females; mean age: 54.5±19.7 years; range, 10 to 98 years) were retrospectively analyzed. Age, sex, and the presence of fabella whether unilateral (left or right) or bilateral were recorded. Of the patients with a bilateral knee CT, those with fabella on one side and without on the other were studied further to investigate the effect of fabella on the posterolateral corner (PLC). In these patients, the LPCO and LPTS values, presence of knee osteoarthritis, fabella-femoral distance, and sagittal anterior-posterior diameter of the fabella were evaluated. RESULTS: While there was no evidence of fabella in 867 (71.1%) patients, it was present in 353 (28.9%) patients. The linear correlation analysis revealed that the correlations between the right LPCO and the right LPTS (r=-0.295; p<0.001) and between the left LPCO and the left LPTS (r=-0.574; p<0.001) were significant. It was observed that LPTS decreased with increasing LPCO. According to the results of the point biserial correlation analysis, there was a significant correlation between the presence of fabella on the right side and the right LPCO value (r=-0.643; p<0.001) and between the presence of fabella on the left side and the left LPCO (r=-0.284; p=0.024). When the two knees were compared, fabella was less present in the knee whose LPCO was higher than that of the other knee, whereas it was more common in the knee whose LPCO was lower than that of the other knee. We found a significant correlation between each side's fabella and LPCO values and between the presence of fabella on the left side and the left LPTS. CONCLUSION: The presence of fabella in the knee joint may be associated with LPCO and LPTS values of the knee. The comparison of the two knees of the same patient may reveal that if a fabella is present in a knee, the LPCO value of that knee is lower than that of the other knee. We believe that the reason for this is that the presence of fabella increases the distance to the center of rotation of the knee joint.

Radiographic and computed tomographic evaluation of supinator sesamoid bones in dogs.

BACKGROUND: The present study evaluated the frequency of supinator sesamoid bones (SSB) on radiography and computed tomography (CT). Interobserver agreement was evaluated in the detection of the SSBs in both methods. A correlation between the existence of SSBs and elbow diseases (ED) was assessed. For these purposes, radiographs, and CT scans of 100 dogs were scored by 3 observers. RESULTS: The SSB was identified as a round to oval-shaped opacity and measured 0.5-6.56 mm × 0.5-6.2 mm. SSBs were reported in an average of 8,33% of dogs on radiographs and 26% of dogs on CT; a bilateral sesamoid bone was present in 43,52% and 76,92% of these dogs, respectively. Seventy-two percent of the SSBs was identified on CT were not detected on radiographs. The Kappa test showed a substantial agreement (κ = 0.691) and a perfect agreement (κ = 1) between the observers in the detection of SSBs on radiography and on CT scans respectively. Additionally, a weak positive correlation was detected between ED and the existence of SSBs. CONCLUSION: A supinator sesamoid bone can be detected occasionally in the evaluation of the canine elbow joints by routine radiography. CT is superior to radiography for assessing SSBs with a higher interobserver agreement. The correlation of the existence of the SSBs and ED, needs further evaluations to prove a probable pathophysiological connection.

Fifth Metatarsal Base Fracture Combined With Fracture of the Os Peroneum.

Fracture of the os peroneum is rare, and displacement of the fracture can be indicative of a tear in the peroneal longus tendon. A fifth metatarsal base fracture is a common injury caused by sudden inversion and plantar flexion of the hindfoot. We observed a rare case of a fifth metatarsal base zone I fracture combined with a displaced os peroneum fracture in a 34-year-old woman. The patient was treated with resection of the os peroneum and repair of the peroneal longus tendon, as well as open reduction and internal fixation of the fifth metatarsal base. After exposing the fragment of the fifth metatarsal base, the distal part of the fractured os peroneum was found to be located just under the fracture site. There were no complications or discomfort of the foot or ankle at 2 years postoperatively. Resection of the os peroneum and direct repair of the peroneal longus tendon were easily performed after the fifth metatarsal base fragment was exposed. This was an innovative method for performing peroneal longus tendon repair in the deep portion of the midfoot.

Kinematics of the equine distal sesamoid (navicular) bone of the thoracic limb.

OBJECTIVE: To quantify the translation and angular rotation of the distal sesamoid bone (DSB) using computed tomography (CT) and medical modeling software. SAMPLE: 30 thoracic limbs from equine cadavers. PROCEDURES: Partial (n = 12), full (8), and matched full and subsequently transected (10) thoracic limbs were collected. Bone volume CT images were acquired in three positions: extension (200° metacarpophalangeal angle), neutral (180°), and maximal flexion (110°). Mean translation and angular rotation of each DSB were recorded. Differences were determined with two-way ANOVA and post hoc Tukey's tests for pairwise comparisons; P value was set at < 0.05. RESULTS: Dorsal translation was significant during extension (1.4 ± 0.4 mm full limbs and 1.3 ± 0.2 mm partial limbs, P < 0.001). Distal translation was significant during extension (1.9 ± 0.4 mm full and 1.1 ± 0.4 mm partial) and flexion (5.4 ± 0.7 mm full and 6.22 ± 0.6 mm partial, P < 0.001). Rotation was significant (P < 0.001) about the mediolateral axis during extension (17.1° ± 1.4°) and flexion (2.6° ± 1.3°). Translation and rotation of the DSB were significantly different (P < 0.001) between full and partial limbs. CLINICAL RELEVANCE: This study provides the first quantification of translation and angular rotation of the DSB within the equine hoof. Partial limbs had significantly reduced movement compared to full limbs, suggesting that transection of flexor tendons alters distal thoracic limb kinematics. Further studies are required to determine if pathologic changes in the podotrochlear apparatus have an impact in clinical lameness outcomes.

Locking of the Metacarpophalangeal Joint of the Thumb Caused by Entrapment of the Radial Sesamoid Bone.

Locking of metacarpophalangeal (MCP) joints of the thumb may be a consequence of dorsal subluxation from hyperextension injury. The joint is locked in mild hyperextension and cannot flex actively or passively. We report four patients with locked MCP joint of the thumb due to radial sesamoid entrapment after hyperextension or forced flexion injury. All patients had a prominent radial condyle of the metacarpal bone. Three patients had a deformity of the longitudinal groove on which the sesamoid was overlaid. The radial sesamoid was entrapped proximal to the radial condyle which could result in limited extension and hinged flexion of the joint. Excision of the radial sesamoid could release the locked joint. The radial sesamoid should be assessed if the motion of the thumb MCP joint is limited after flexion or extension injury. Level of Evidence: Level V (Therapeutic).

Proximal sesamoid bone microdamage is localized to articular subchondral regions in Thoroughbred racehorses, with similar fracture toughness between fracture and controls.

OBJECTIVE: To determine whether proximal sesamoid bone (PSB) microdamage and fracture toughness differ between Thoroughbred racehorses sustaining PSB fracture and controls. STUDY DESIGN: Cadaveric case-control. ANIMALS: Twenty-four Thoroughbred racehorses (n = 12 PSB fracture, n = 12 control). METHODS: Proximal sesamoid bones were dissected, and gross pathological changes and morphological measurements were documented. High-speed exercise history data were evaluated. Microdamage was assessed in fracture, fracture-contralateral limb (FXCL) and control PSBs using whole bone lead uranyl acetate (LUA) staining with micro-CT imaging or basic fuchsin histological analysis. Fracture toughness mechanical testing was carried out in 3-point-bending of microbeams created from PSB flexor cortices. Data were analyzed using ordinal logistic and linear regression models. RESULTS: Microdamage was detected most commonly in the articular subchondral region of PSBs via LUA micro-CT and basic fuchsin histology. There were no differences in microdamage between FXCL and control PSBs. Fracture toughness values were similar for FXCL (1.31 MPa√m) and control (1.35 MPa√m) PSBs. Exercise histories were similar except that horses sustaining fracture spent a greater percentage of their careers in rest weeks. CONCLUSION: Microdamage was detected in the articular region of PSBs but was not greater in horses sustaining catastrophic PSB fracture. Fracture toughness of PSB flexor cortices did not differ between FXCL and control PSBs. CLINICAL SIGNIFICANCE: Although uncommon, microdamage is localized to the articular region of Thoroughbred racehorse PSBs. Catastrophic PSB failure is not associated with lower PSB flexor cortex fracture toughness.