Os Subepicondylare Mediale in the Elbow: A Radiographic Case Report of a Sesamoid Bone.

Sesamoid and accessory bones are small, oval-shaped structures that develop within tendons that pass over bony prominences. Although rare, accessory bones in the elbow region hold clinical significance because they can cause diagnostic uncertainty. We present the case of a 47-year-old previously healthy female patient who presented with left elbow pain and was discovered to have a sesamoid bone distal to the medial epicondyle of the humerus. On examination, the patient's left elbow was tender, but her range of motion was in normal range. Plain radiographs identified a small, oval-shaped bony fragment; further radiographic investigations were conducted. Computed tomography and ultrasound were performed to rule out diagnostic uncertainties. A diagnosis of os subepicondylare mediale, a rare sesamoid bone, was established through a thorough investigation of the well-circumscribed structure in accordance with the most current literature.

The Application of Sesamoid Position in Diagnosing Thumb Metacarpophalangeal Joint Dorsal Dislocation: A Retrospective Study.

OBJECTIVES: The position of sesamoid of thumb metacarpophalangeal (MCP) joint changed clearly when the joint was dislocated dorsally. However, the significance of sesamoid location in diagnosing joint dislocation was unclear. The present study aimed to explore the positional relationship between sesamoid bone and thumb metacarpophalangeal joint in normal and dorsal dislocation joints. METHODS: Between January 2018 and August 2023, we collected 60 isometric plain films from sixty outpatients and reviewed 56 anisometric plain films from twenty-eight emergency patients with dorsal dislocation of thumb MCP joint at Tianjin Hospital, then took measurements on the hand X-ray images. The sesamoid length on its longitudinal axis was defined as DP, the distance between the distal edge of sesamoid and thumb MCP joint was defined as DJ, and the ratio of DJ and DP was R. An independent-samples t-test and paired-samples t-test was utilized to analyze difference among data groups. RESULTS: The 60 isometric images were from 30 male and 30 female outpatients with normal bone structure in their hands, and the 56 anisometric images of the 28 emergency patients included both preoperative and postoperative materials. Among the outpatients, the actual distance between the distal edge of sesamoid and thumb MCP joint space (DJ) was 2.09 mm and 1.40 mm in males and females, respectively. The authentic average length of sesamoid (DP) was 4.46 mm in males and 4.22 mm in females. The average value of R (the ratio of DJ and DP) in males and females was 0.49 and 0.34, respectively. There were gender-related statistical differences in DJ (p < 0.01) and R (p=0.01), but no statistical difference in DP (p > 0.05). For the 28 emergency patients, the mean value of R was -0.47 before joint reduction and 0.58 after joint reduction, with statistical difference between them (p < 0.01). CONCLUSIONS: There was significant difference in the relative position between sesamoid and thumb MCP joint when joint dislocation and joint reduction. The distal edge of sesamoid beyond thumb MCP joint could be an evidence in diagnosing joint dorsal dislocation. The distal edge of sesamoid below thumb MCP joint could be an evidence of joint reduction.

Comparison of 18 F-sodium fluoride positron emission tomography and computed tomography for imaging of the fetlock in 25 nonracehorses.

BACKGROUND: 18 F-sodium fluoride (18 F-NaF) positron emission tomography (PET) has been validated as a useful imaging technique in the racehorse fetlock. The use of 18 F-NaF PET in the nonracehorse fetlock has not been reported. OBJECTIVES: To describe 18 F-NaF PET findings in nonracehorse fetlocks, to compare with computed tomography (CT) findings and to compare PET findings between horses with and without fetlock pain. STUDY DESIGN: Retrospective observational study. METHODS: All horses undergoing 18 F-NaF PET and CT imaging of the fetlock between October 2016 and March 2021 were included in the study. Medical records were reviewed for associated lameness information. RESULTS: Thirty-six fetlocks (33 front and 3 hind) from 25 horses were included. The interobserver agreement for PET [0.62 (95% confidence interval [CI] 0.59-0.65)] was higher than for CT [0.47 (95% CI 0.43-0.51)]. Increased 18 F-NaF uptake was most common in the medial subchondral bone of the proximal phalanx (23/36), the dorsomedial (20/36) and dorsosagittal (16/36) metacarpal/metatarsal distal subchondral bone, whereas sclerosis was identified on CT in these areas in 22 of 36 (p > 0.9), 33 of 36 (p = 0.001) and 23 of 36 (p = 0.15), respectively. Significant correlations were found between PET grades and both subchondral sclerosis and resorption CT grades (p < 0.001, Spearman r = 0.19 and 0.21, respectively). Abnormal 18 F-NaF uptake in the proximal sesamoid bones (PSBs) was identified in 12 of 36 of the fetlocks, which was more common than CT abnormalities (3/36, p = 0.02). Periarticular increased uptake was seen in 7 of 36 fetlocks, whereas osteophytosis was recognised on CT in 20 of 36 (p = 0.1). Maximal standardised uptake values (SUVmax) were significantly higher in painful than in nonpainful fetlocks (22.0 and 11.9, respectively, p = 0.038). MAIN LIMITATIONS: Retrospective study and limited sample size. CONCLUSIONS: Overall PET and CT findings follow a similar distribution in their location. PET identified more abnormalities in the PSBs than CT. SUVmax is a pertinent factor to take into consideration for the assessment of the clinical significance of findings.

Dorsal Dislocation of the First and Second Metatarsophalangeal Joint: A Case Report and Literature Review.

Dorsal dislocation of the toes is an infrequent injury that can result in severe pain and deformity. Timely diagnosis and appropriate management are paramount for optimizing patient outcomes. This case report illustrates a 53-year-old male patient who suffered dorsal dislocation of the first and second metatarsophalangeal (MTP) joints due to a crush injury. We present the clinical manifestation, radiographic findings, and management approach for this unique isolated first and second ray MTP joint dorsal dislocation, without any associated fractures. This case report underscores several critical observations: firstly, hallux dorsal dislocation can potentially coincide with other injuries; secondly, it can stem from crushing trauma to the big toe; and thirdly, successful closed reduction, when followed by effective immobilization and early rehabilitation, can yield outstanding outcomes. Additionally, the report emphasizes the importance of pursuing another closed reduction attempt under general anesthesia, if the initial attempt in the emergency room proves unsuccessful, before contemplating open reduction.

Relationship between skeletal maturity indicators and dental calcification stages in a sample pediatric population.

Context: Human growth shows considerable variation. In addition to constitutional differences in the timing of maturation, there are diseases, systemic disorders and environmental factors that may affect a child's physiologic maturity. Interrelationships among skeletal, somatic and sexual maturity have been shown to be consistently strong. The study was conducted to evaluate the relationship between dental calcification stages and skeletal maturity indicators. Materials and Methods: The hand wrist radiographs, the lateral cephalogram and the orthopantomogram (OPG) of 120 patients (60 males and 60 females, age group 8-14 years) were taken. The hand wrist radiographs were analyzed using Fishman's skeletal maturity index (SMI), and the cephalograms analyzed by cervical vertebrae maturation (CVM) by Baccetti. OPG was analyzed according to the Demirjian's system. Result: On assessment, cervical vertebrae maturation indicator (CVMI) staging showed significant results with a correlation coefficient of 0.716 being the highest in canines in males while assessment of dental calcification stages and its comparison with skeletal maturity indicator showed insignificant results. The correlation coefficient values were 0.11, 0.09, 0.09 and 0.13 for canine, first premolar, second premolar and second molar respectively. Conclusion: There is a strong correlation between the maturation stage of cervical vertebrae and calcification stages of canine, first premolar, second premolar and second molar as determined by Demirjian's method.

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.

Relationship Between Hallux Valgus Recurrence and Sesamoid Position on Anteroposterior Standing Radiographs After Distal Chevron Metatarsal Osteotomy.

BACKGROUND: Recurrence of the hallux valgus deformity has various causes, and the incomplete reduction of sesamoids may be one of the important issues. However, we have seen several patients with postoperative lateral sesamoid displacement on anteroposterior (AP) standing radiographs who did not experience hallux valgus recurrence. Therefore, we hypothesized that lateral displacement of the sesamoid on AP standing radiographs does not cause hallux valgus recurrence. METHODS: The study included 269 feet (185 patients) with hallux valgus treated with distal chevron metatarsal osteotomy. Mean patient age was 64.26 (range, 15-80) years. Patients were followed up for an average of 33.85 (range, 12-228) months between April 2002 and December 2019. The patients were divided into 4 groups, according to the presence or absence of hallux valgus recurrence and sesamoid reduction. RESULTS: During outpatient follow-up, we discovered 99 feet (42.1%) in which hallux valgus did not recur despite lateral sesamoid displacement (grade IV-VII) on AP standing radiographs. Hallux valgus angle (HVA, 2.7 to 7.9 degrees), intermetatarsal angle (IMA, 4.6 to 6.2 degrees), and sesamoid grades (2.1 to 3.5) all deteriorated over time after surgery, and each indicator was statistically significantly altered, and changes in the 3 indicators had a statistically significant positive correlation. Changes in HVA and IMA between feet with and without sesamoid reduction on AP standing radiographs increased over time, with the differences in HVA (2.9 degrees) and IMA (0.9 degrees) being significant at final follow-up (P < .05 for each). Regardless of whether sesamoid reduction was achieved on AP standing radiographs, the final analysis showed that HVA and IMA in both groups worsened over time. Further, there were no differences between the 2 groups in the patterns of change over time. CONCLUSION: In our cohort, postoperative sesamoid position on AP standing radiographs was not associated with hallux valgus recurrence based on radiographic criteria. LEVEL OF EVIDENCE: Level III, retrospective comparative study.

Gross anatomy, computed tomography, magnetic resonance imaging and bone mineral densitometry of the ovine metacarpo/metatarsophalangeal joint.

This study was aimed to provide anatomical atlas of the ovine metacarpo/metatarsophalangeal joints using computed tomography (CT) scan and magnetic resonance imaging (MRI), as well as to investigate bone mineral density (BMD) and morphometric features of this joint. The limbs of twenty adult Sanjabi sheep were examined. Imaging was performed using a 16-slice multi-detector CT scanner and a 1.5 Tesla MRI scanner. The obtained images were correlated with corresponding anatomical sections. BMD was measured by Dual Energy X-ray Absorptiometry (DEXA) method. Also morphometric features included distance between metacarpal and metatarsal heads, width of metacarpal and metatarsal head, length, width and the height of the proximal sesamoid bones were measured. In MRI images, compact bones, ligaments and tendons showed less signal intensity (hypointense). The fatty tissue and bone marrow had more signal intensity (hyperintense), but articular cartilage and synovial fluid showed moderate signal intensity. BMD in the left hind limb was significantly higher than other three limbs (p ≤ 0.05). The length of proximal sesamoid bones in left forelimb was higher than right forelimb (p ≤ 0.05). The thickness of proximal sesamoid bones in left limbs was higher than those in their counterparts (p ≤ 0.05). The width of the medial head in the forelimbs was significantly greater than the hind limbs (p ≤ 0.05). The present results might be useful in managing the clinical techniques on this joint. Larger volume of the proximal sesamoid bones and wider medial head in the forelimbs compared to the hindlimbs impel this speculation that the centre of gravity is closer to the forelimbs.

Alterations to the synovial invaginations of the navicular bone are associated with pathology of both the navicular apparatus and distal interphalangeal joint when evaluated using high field MRI.

Limited information exists regarding associations between distal interphalangeal joint (DIPJ) abnormalities and synovial invagination changes in the distal sesamoid (navicular) bone. This retrospective, analytical study aimed to measure specific characteristics of the synovial invaginations of the navicular bone to determine whether any single characteristic was associated with abnormalities in the DIPJ or navicular apparatus (NA) using high field MRI and a sample of 200 horses' feet. The DIPJ and NA were graded independently by three scorers. The grades were averaged, creating a global pathology score for the DIPJ, NA, and synovial invaginations. Higher global scores represented more severe pathology. The number of invaginations, depth of penetration, invagination shape, and cross-sectional area (CSA) of the largest invagination were recorded. Interobserver agreement was measured using Cohen's Kappa. Associations of global scores of the DIPJ and NA with individual invagination characteristics were assessed using linear mixed modeling. A significant relationship was found between the number of invaginations and global DIPJ score, with higher invagination numbers associated with higher DIPJ scores. For invagination depth and CSA, a significant relationship was noted with global scores of both the DIPJ and NA. Reliable relationships between the shape of synovial invaginations and global scores of DIPJ and NA were not found, likely due to poor interobserver scoring (0.305). These findings suggest that primary DIPJ disease and NA pathology should be considered when noticing alterations to navicular synovial invaginations on MRI. This contrasts traditional views that synovial invagination abnormalities are indicative solely of NA pathology.

Prevalence and Radiological Characteristics of the Fabella in Turkish Population.

BACKGROUND: This study aimed to evaluate and analyze the prevalence and radiological characteristics of the fabella in the Turkish population, detecting differences between genders by examining magnetic resonance imaging (MRI) images of subjects. METHODS: A total number of 504 patients aged >18 years who were admitted to the orthopedics and traumatology clinic between November 2018 and October 2020 were included in this retrospective cross-sectional study. Bilateral MRI images that were taken from each patient were randomly selected. Age, sex, laterality (right or left knee), and size of the fabella were retrieved from institutional database records. P-value<0.05 is considered statistically significant. RESULTS: A total of 504 patients were included with 213 males and 291 females. The overall prevalence of fabella was 20.63%. The mean length, thickness, and width of the fabella were 6.05 mm, 4.63 mm, and 5.92 mm, respectively, in the overall population. The fabella was significantly wider, thicker, and longer in males compared to females in the Turkish population. CONCLUSION: This study revealed similar prevalence rates of the fabella in the Turkish population with Caucasian populations and similar size of the fabella in the Asian population. When different prevalence rates and sizes of the fabella among different ethnic populations are considered, it is critical to understand the prevalence or radiological features of the fabella in Turkish subjects to avoid misinterpretation of fabella diseases.

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.

The Improved Proximal Phalanx Osteotomy for Reducing Sesamoid in Hallux Valgus Surgery-A Cadaver Study.

A metatarsal osteotomy is known to have the effect of reduction of the sesamoid. However, the reduction of the sesamoid is not always completed by a metatarsal osteotomy alone. The purpose of this cadaver study was to show that the improved technique of a modified Akin proximal phalanx osteotomy (MPO) could be helpful for the reduction of the sesamoids in hallux valgus surgery. Ten feet of cadavers were used; the cadavers had hallux valgus on both feet. The first trial of two feet underwent only the MPO. The other eight feet underwent a proximal metatarsal chevron osteotomy and MPO simultaneously. The hallux valgus angle, intermetatarsal angle, Hardy's grade, and Smith's grade were measured. To predict possible complications, cadavers were dissected after surgery. In the feet that underwent an MPO only, the hallux valgus angle and sesamoid position were improved. In the feet that underwent an MPO and metatarsal osteotomy, the hallux valgus deformity was completely corrected, and the sesamoid position was improved. Overall, the hallux valgus angle and intermetatarsal angle improved from 30.6 to 8.4 degrees and from 11.2 to 4.1 degrees, respectively. The sesamoid position was reduced from 5.3 to 2.5 (Hardy) and from 1.7 to 0.7 (Smith). The MPO combined with the metatarsal osteotomy were helpful for reducing the sesamoids compared to the metatarsal osteotomy only.

Could the Prevalence and Distribution of Os Supratrochleare Dorsale and Patella Cubiti be the Key to Accurate Diagnosis?

Background: The aim of this study was the prevalence of patella cubiti and os supratrochleare dorsale, and to detect the differences between genders. Materials and Methods: In the study, direct radiographs of 1646 people (959 females and 687 males), who presented to Firat University Hospital between 01.01.2016 and 31.01.2019 and had elbow joint radiographs, were evaluated retrospectively. Of the radiographs evaluated, 346 were right and left elbow radiographs of the same people, 689 were just right elbow radiographs, and 611 were only left elbow radiographs. Results: The prevalence of os supratrochleare dorsale was 2.08% (20 in 959 women) in women, 2.62% (18 in 687 men) in men, and 2.3% (38 in 1646 people) in total. The prevalence of patella cubiti was found to be 0.42% (4 in 959 women) in women, 1.31% (9 in 687 men) in men, and 0.79% (13 in 1646 people) in total. In addition, the prevalence of both sesamoid bones only in the left elbow and in both elbows was determined with and without separation according to male-female genders. Conclusion: We are of the opinion that knowing the prevalence and distribution of these sesamoid bones will help with establishing early and correct diagnoses for patients who present with complaints, such as elbow extension limitation and pain in the elbow area.

Fabella syndrome in a professional football player: A case report and literature review.

INTRODUCTION AND IMPORTANCE: Fabella syndrome is a rare cause of posterolateral knee pain. The definitive diagnosis and management of this syndrome remain unclear. CASE PRESENTATION: We report a case of a 19-year-old patient who is a Vietnamese professional football player. He presented with persistent pain in the posterolateral aspect of the knee joint for 12 months that was unrelated to trauma. He was treated conservatively for 6 months without any improvement in the previous hospital. He was diagnosed with fabella syndrome and underwent open surgery to remove the bone. Evaluation after surgery 12 weeks revealed the symptoms disappeared and he was able to return to practice. CLINICAL DISCUSSION: In order to diagnose fabella syndrome, the clinicians need to be vigilant and base on the clinical signs as well as imaging to exclude other causes of posterolateral knee pain. Conservative therapy is always the first choice of treatment although the recurrence rate is high, especially in professional athletes. If the initial conservative therapies failed, the fabella surgical removal surgery should be made in athletes. CONCLUSION: Fabella syndrome is a rare cause of posterolateral knee pain in professional athletes. The definitive diagnosis and management of this syndrome remain unclear. Our case shows that surgical removal of the bone fragments can be considered if failure after the initial conservative therapies.

The sesamoid bone in the long abductor muscle tendon of the first digit in the dog.

The sesamoid bone in the tendon of the m. abductor digiti primi longus is considered present in most dog breeds and is described to be radiologically detectable at the level of the carpus from the age of 4 months. However, an extensive investigation of this sesamoid bone has not been conducted before. The aim of this study was therefore to determine its prevalence in different dog breeds, to describe its histological development, and to determine the age at which it becomes radiologically visible. The prevalence of the sesamoid bone was assessed on radiographic images of the carpus or by dissection of the carpal region in 743 adult dogs of 115 breeds. Its development was studied by dissection and histological analysis in 45 puppies and its timing of radiological appearance was evaluated in 209 puppies. At least one sesamoid bone was present in all adult dogs, except for 14 dogs of six breeds of predominantly the small breed category. The lowest prevalence rate of 38.46% was exhibited in the French bulldog. The histological development could be divided into five stages. The first radiographic appearance corresponded to the coalescence of smaller ossification centers into one big nucleus (stage 4). The mean time of radiographic appearance was 108.4 days. This study provides extensive data on the prevalence and timing of the radiographic appearance of a sesamoid at the carpus of the dog. The data on radiographic appearance may be helpful in the age estimation of puppies.

Dislocation of the metacarpophalangeal joint of the index finger requiring open reduction due to the presence of an intra-articular sesamoid bone.

Complex dislocation of the metacarpophalangeal joint of the index finger is rare and often requires surgical intervention. Here, we present a case of an index finger metacarpophalangeal joint dislocation requiring open reduction due to obstruction by a displaced volar plate and the intra-articular entrapment of a sesamoid bone. Surgical approach was performed dorsally, allowing easy visualization of the volar plate and sesamoid bone as well as minimizing risk to the radial digital nerve to the index finger. Postoperatively, the patient reported good functional return despite the delay in definitive management.

Prevelance of Fabella: An MRI Study in The Eastern Anatolia Region of Turkey.

BACKGROUND: The fabella, which is generally located in the lateral head of the gastrocnemius muscle, is a sesamoid bone that articulates with the posterior face of the lateral femoral condyle. As traditional information, the prevalence of fabella is between 10-30% in the population and is usually present in both knees. INTRODUCTION: The objective of this study was to investigate the knee MRIs in the Eastern Anatolia Region of Turkey subjects in order to assess the prevalence of the fabella and analyse the differences between gender, age and laterality and its symmetry pattern. METHODS: This study was a retrospective study in patients older than 18 years whose knee MRIs were taken between February 2014 and February 2016. In this study, a total of 531 patients (290 females and 241 males) were included. The radiographs were examined by two orthopedic surgeons and the fabella was located. Later, an expert radiologist made the final decision and confirmed the results. RESULTS: The number of patients included in the study was 531. We detected os fabella in 59 (11.1%) patients. Of the 59 os fabella, 33 were in the right knee and 26 were in the left knee, 38 were female and 21 were male. CONCLUSION: In this study, we investigated the age and gender differences besides the prevalence and the symmetry pattern of the fabella in the Eastern Anatolia Region of Turkey's population. Prevalence of the fabella was found to be 11.1% which is different than previously published studies.

Microstructural properties of the proximal sesamoid bones of Thoroughbred racehorses in training.

BACKGROUND: Proximal sesamoid bone fractures are common catastrophic injuries in racehorses. Understanding the response of proximal sesamoid bones to race training can inform fracture prevention strategies. OBJECTIVES: To describe proximal sesamoid bone microstructure of racehorses and to investigate the associations between microstructure and racing histories. STUDY DESIGN: Cross-sectional. METHODS: Proximal sesamoid bones from 63 Thoroughbred racehorses were imaged using micro-computed tomography. Bone volume fraction (BVTV) and bone material density (BMD) of the whole bone and four regions (apical, midbody dorsal, midbody palmar and basilar) were determined. Generalised linear regression models were used to identify the associations between bone parameters and race histories of the horses. RESULTS: The mean sesamoid BVTV was 0.79 ± 0.08 and BMD was 806.02 ± 24.66 mg HA/ccm. BVTV was greater in medial sesamoids compared with lateral sesamoids (0.80 ± 0.07 vs 0.79 ± 0.08; P < .001) predominantly due to differences in the apical region (medial-0.76 ± 0.08 vs lateral-0.72 ± 0.07; P < .001). BVTV in the midbody dorsal region (0.86 ± 0.06) was greater than other regions (midbody palmar-0.79 ± 0.07, basilar-0.78 ± 0.06 and apical-0.74 ± 0.08; P < .001). BVTV was greater in sesamoids with more microcracks on their articular surface (Coef. 0.005; 95% CI 0.001, 0.009; P = .01), greater extent of bone resorption on their abaxial surface (Grade 2-0.82 ± 0.05 vs Grade 1-0.80 ± 0.05 or Grade 0-0.79 ± 0.06; P = .006), in horses with a low (0.82 ± 0.07) or mid handicap rating (0.78 ± 0.08) compared with high rating (0.76 ± 0.07; P < .001), in 2- to 5-year-old horses (0.81 ± 0.07) compared with younger (0.68 ± 0.08) or older horses (0.77 ± 0.08; P < .001) and in horses that commenced their racing career at less than 4 years of age (0.79 ± 0.08 vs 0.77 ± 0.77; P < .001). BMD was greater in the midbody dorsal (828.6 ± 19.6 mg HA/ccm) compared with other regions (apical-805.8 ± 21.8, midbody palmar-804.7 ± 18.4 and basilar-785.0 ± 17.1; P < .001), in horses with a handicap rating (low-812.1 ± 20.0, mid-821.8 ± 21.3 and high-814.6 ± 19.4) compared with those with no rating (791.08 ± 24.4, P < .001), in females (806.7 ± 22.0) and geldings (812.2 ± 22.4) compared with entires (792.7 ± 26.2; P = .02) and in older horses (<2-year-old-763.7 ± 24.8 vs 2- to 5-year-old-802.7 ± 23.4, and 6- to 12-year-old-817.8 ± 20.0; P = .002). MAIN LIMITATIONS: Data were cross-sectional. CONCLUSIONS: Densification of the proximal sesamoid bones is associated with the commencement of racing in younger horses and the presence of bone fatigue-related pathology. Lower sesamoid BVTV was associated with longevity and better performance.

Ossification timeline of sesamoid bones at metatarsophalangeal joints.

Ossification timeline is a critical issue in studies regarding sesamoid bones at metatarsophalangeal (MTP) joints, but actual knowledge is still incomplete. The present study determines the cutoff age of sesamoids ossification at MTP joints. We conducted a retrospective review of radiographs of the feet from 5553 males and 3225 females between November 2005 and September 2012 to identify presence of sesamoids at 5 MTP joints and 3 variations of hallucal sesamoids. Age-specific prevalence of each presence and variations was calculated and clustered to produce latent age groups corresponding to the sesamoid ossification process in males and females, respectively. Males older than 7 years of age were divided into 5 age groups (8-11, 12-15, 16-29, 30-76, and 77-92 years), while females were classified into 4 age groups (8-11, 12-26, 27-76, and 77-92 years). According to the characteristics of sesamoid prevalence in each age group, the pre-ossification stage was defined at age 1-7 years in both genders and the ossifying stage was defined at age 8-29 years in males and 8-26 years in females. We also defined ossified stage as age 30-92 years in male and 27-92 years in females. The ossifying and ossified stages include 2 or 3 substages in both genders. A clustering analysis provided novel cutoff age points as ossification timelines for the sesamoid bones at MTP joints in males and females, which may have an impact on future sesamoid and skeletal development research.

[Relationship between fabella and posterolateral knee pain and common peroneal nerve injury].

OBJECTIVE: To analyze the incidence and characteristics of fabella in the Chinese population and its correlation with pain in the posterolateral region of the knee joint and common peroneal nerve palsy. METHODS: Total 732 patients including 405 males(450 knees) and 327 females(383 knees) who underwent unilateral or bilateral knee MR imaging from September 2015 to July 2019 were retrospectively evaluated. The basic information of all patients was extracted from the hospital's his system. The patient's medical records were checked by telephone follow-up or his system, and the number of patients with posterolateral knee pain and common peroneal nerve paralysis were recorded. RESULTS: The overall prevalence of fabella was 48.38%, 23.53% in men and 24.85% in women, there was no significant difference between them (P>0.05). All the subjects were divided into five age groups. The prevalence of fabella was significantly different among different age groups:6.6% in 20 year-old group, 33.8% in 21 to 34-year-old group, 53.5% in 35 to 44-year-old group, 57.5% in 45 to 59-year-old group and 73.9% in ≥ 60-year-old group, the difference was statistically significant (P<0.001). There was a significant correlation between the prevalence of fabella and the age of patients. With the increase of patients' age, the prevalence of fabella in knee joint also showed an obvious upward trend (P<0.001). According to the presence of fabella in the knee joint, 232 cases of knee joint pain were found, accounting for 57.57% of the patients with fabella, accounting for 27.85% of the total data(P<0.01). The correlation score analysis was R=1.546, P<0.01;when the presence of fabella in the knee joint, a total of 44 cases of common peroneal nerve paralysis occurred in the knee joint, accounting for all knees 28% of the total knee joint, and 29 cases of common peroneal nerve palsy (3.48% of the total knee joint) were found when there was no fabella in the knee joint(P<0.05). The correlation score analysis was performed with R=1.695, P<0.05. CONCLUSION: The prevalence of fabella us in Chinese population is 48.38%. There is no relationship between the incidence of gastrocnemius and gender, but the incidence of fabella is positively correlated with age, pain in the posterolateral region of the knee joint and the occurrence of common peroneal nerve symptoms.