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PubMed1994

The effect of hallux sesamoid resection on the effective moment of the flexor hallucis brevis.

In this cadaver study, the functional significance of the hallux sesamoid bones was quantified by measuring the effective tendon moment arm (ETMA) of the flexor hallucis brevis (FHB) force. (The ETMA differs from the anatomic tendon moment arm in that ETMAs are determined by the experimentally measured moment of the tendon force, rather than by the actual location and orientation of the tendon pull in the joint). The intact case was compared with three levels of progressive sesamoid resection: distal half of the medial sesamoid excised, entire medial sesamoid excised, and both the medial and lateral sesamoids excised. Five dorsiflexion angles of the metatarsophalangeal joint were tested, ranging from -10 degrees to 50 degrees. A known active load was applied to the FHB muscle of fresh frozen cadaver specimens while the corresponding resisting forces from three orthogonally mounted transducers were being recorded. Results showed that the ETMAs decreased significantly (P < .05) only with the excision of both sesamoids. The percent decrease in ETMA was smallest at dorsiflexion angles of -10 degrees and 15 degrees (4.3% and 2.4%, respectively) and largest at dorsiflexion angles of 25 degrees, 35 degrees, and 50 degrees (29.2%, 22.4%, and 26.7%, respectively). The clinical significance of the results is that distal hemiresection of the medial sesamoid or full medial sesamoid excision is unlikely to appreciably compromise the effective mechanical advantage of the FHB muscle. However, this mechanical advantage may be profoundly diminished by excision of both hallux sesamoids.

Biomechanical Phenomena↗

PubMed1990

On the collateral sesamoidean (suspensory navicular) ligament of equines: topographic relations and sensitive innervation.

The origin and course of the collateral sesamoidean (suspensory navicular) ligament of the horse and ass and its attachment to the distal sesamoid bone were studied by means of dissection. Particular attention was given to the topographic relations between this ligament and the deep digital flexor tendon. Numerous sensitive nerve endings are present in this anatomical district. The free and encapsulated nerve endings, displayed by impregnating techniques, are mostly concentrated in the ligament tract connected to the above-named tendon and close to its attachment to the distal sesamoid angle. The nerve endings are identified as typical Pacini, Pacini-like and Golgi-Mazzoni corpuscles on account of their morphological features and are found isolated, grouped to form flower-sprays, lined up along the course of a single nerve fibre or grouped to originate poikilomorphous fibres.

Animals↗

PubMed1992

Bi- and three-dimensional CT study of carpal bone motion occurring in lateral deviation.

A computed tomography (CT) study of the right wrists of 15 volunteers and of 5 anatomical preparations in neutral position, radial (15 degrees) and ulnar (30 degrees) deviation enables to tackle the qualitative analysis of carpal bone motion. The CT Scans were analyzed and reconstructed in three dimensions by means of the Philips CAMRA S100 computer program. The results show that the capitate, the metacarpals II and III and, to a lesser extent, the trapezium and the trapezoid are poorly mobile. Our study points to the role of the flexor and extensor carpi ulnaris muscles in the stability of the internal carpus, confirming that the pisiform is a sesamoid bone in the flexor carpi ulnaris tendon. A model of longitudinal functional structure of the carpus during lateral deviation, intermediate between those of Navarro and Taleisnik, is proposed.

Adult↗

PubMed1992

Ankylosis of the distal interphalangeal joint in a horse after septic arthritis and septic navicular bursitis.

A 6-month-old 300-kg Quarter Horse filly was treated for septic arthritis of the distal interphalangeal joint and septic navicular bursitis that developed as a result of a deep puncture to the foot. Initial treatment consisted of establishing ventral drainage for the navicular bursa, lavage of the distal interphalangeal joint, and administration of broad-spectrum antimicrobial drugs and non-steroidal anti-inflammatory drugs. Because of continuing sepsis in the distal interphalangeal joint, subsequent treatment included packing the defect in the bottom of the foot with cancellous bone in an attempt to prevent ascending contamination of the joint, placing the limb in a short limb cast, and inserting a Penrose drain into the joint for passive drainage of septic exudate. The goal of treatment was to encourage ankylosis of the distal interphalangeal joint. Because of the filly's persistent lameness and laxity of the lateral collateral ligament in the contralateral carpus, the palmar nerves of the affected foot were injected with a long-acting local anesthetic at the level of the proximal sesamoid bones to encourage weight-bearing. Ankylosis of the distal interphalangeal joint was complete 9 months after the puncture, but a grade-2 lameness remained and the horse had a varus deformity resulting from ligamentous laxity of the lateral collateral ligament in the contralateral carpus.

Animals↗

PubMed1990

Absence of an osseous patella and other observations in Macropodidae stifle.

The patella is a large sesamoid bone that typically develops in the tendon of insertion of the large extensor muscles of the stifle joint. Although present in almost all species of mammals and birds, it has been found to be absent in the red kangaroo and two wallaby species (family Macropodidae). In its place is a fibrocartilage pad, located in the tendon of the quadriceps femoris muscle. This structure is visible grossly, is palpable, and has the form normally expected of a bony patella. In addition, the femoral trochlea is shallow and asymmetric, and the lateral gastrocnemius sesamoid is unusually prominent. These and other related modifications in the area of the Macropodidae stifle are presented.

Animals↗

PubMed1988

Geometry of the first metatarsophalangeal joint.

This study aimed to define the articular geometry of the metatarsophalangeal (MTP) joint of the great toe. Embedded in resin blocks, five pairs of cadaveric first MTP joints (all from men) were sequentially cut in the sagittal plane with a milling machine, removing 0.5 mm of bone in each cut. The photographed cartilaginous outline of each cut was digitized against reference markers, which enabled a computer system to superimpose each outline in three dimensions. The intersesamoidal ridge was found to be parallel to the lateral shaft. The peak of the ridge was just lateral to the midline of the MT head. The articular outline, through the ridge of each sample, was circular; however, other surface contours were noncircular. The undulating plantar aspect of the MTP head formed by the intersesamoidal ridge and related grooves was found to have symmetric relationships to the sesamoid bones and a consistent orientation to the shaft. The rounded distal dorsal aspect of the MTP head showed consistent differences to the concavity formed by the phalangeal base. The sample size is too small for the sizing of prostheses but it is adequate to study the geometry of the MTP joint. More data are needed for the accurate replication of a resurfacing prosthesis and understanding of joint kinematics.

Cartilage, Articular↗

PubMed1998

Longitudinal fractures of the condyles of the third metacarpal and metatarsal bones in racehorses: 224 cases (1986-1995).

OBJECTIVE: To determine type, distribution, and radiographic appearance of condylar fractures of the third metacarpal bone (MC-3) or third metatarsal bone (MT-3) in Thoroughbreds (TB), Standardbreds (SB), and Arabians, to assess long-term outcome of horses in which fractures were repaired surgically, and to identify variables associated with prognosis for return to racing. DESIGN: Retrospective study. ANIMALS: 224 horses with 233 fractures. PROCEDURE: Medical records and radiographs obtained before and after treatment were reviewed. Racing performance before and after treatment was determined by reviewing race records. RESULTS: TB were overrepresented and SB were underrepresented, compared with the hospital population. Thoroughbreds had significantly more lateral condylar fractures and significantly more forelimb fractures than did SB. Thoroughbreds were less likely to race after treatment if they had complete, rather than incomplete, lateral condylar fracture or had concurrent proximal sesamoid bone fracture. Convalescent time for TB with medial condylar fractures of MT-3 was significantly longer than that for TB with lateral condylar fractures of MT-3. CLINICAL IMPLICATIONS: Horses with condylar fractures of MC-3 and MT-3 that had minimal pathologic changes in the involved joint had a favorable prognosis for returning to racing after surgical treatment. Prognosis for horses with complete condylar fractures, particularly those with substantial pathologic changes in the involved joint, was worse.

Animals↗

PubMed2003

Carpal ontogeny in Monodelphis domestica and Caluromys philander (Marsupialia).

Carpal bones have experienced numerous changes during marsupial evolution, even though their diversity and development remain poorly studied. The aim of this work was to document adult form and the pattern of mesenchymal tissue condensation and formation of chondrification and ossification centers in the hand of two marsupials. Two fundamental questions were asked: whether the loss of embryonic precursors was associated with the loss of adult elements, or whether there were developmental signs of ancestral mammalian elements that have been fused or lost in marsupial taxa. We were also interested to find out whether there is sexual dimorphismus in the carpals, as has been reported for some didelphids. Histological sections, cleared and stained specimens and macerated skeletons representing an ontogenetic series of Monodelphis domestica were used to document carpal development. Comparisons were made with perinatal stages of Caluromys philander and with adult specimens of other marsupials. A prenatal M. domestica in the 13th day after conception has a cell condensation that because of its position is homologized with a centrale, which is at birth already lost or fused. Neonatal M. domestica and C. philander have the number and arrangement of their adult carpal anatomy. Trapezium and trapezoid start ossification later than most other carpals, while pisiform and prepollex are the last to do so. Adult males of M. domestica have relatively larger and more robust pisiforms, compared to other carpals, than females. This sexual dimorphism develops relatively late as it was not recorded in male specimens around 160 days old. An extra sesamoid bone located just distal to the radius and proximo-palmar to the scaphoid was recorded in specimens of C. philander, C. derbianus and Didelphis virginiana.

Journal Article↗

PubMed2003

Comparative morphology of the pollical distal phalanx.

Functional analysis of human pollical distal phalangeal (PDP) morphology is undertaken to establish a basis for the assessment of fossil hominid PDP morphology. Features that contribute to the effectiveness of grips involving the distal thumb and finger pulp areas include: 1) distal thumb interphalangeal joint morphology, facilitating PDP conjunct pronation with flexion; 2) differentiation of a proximal, mobile pulp region from a distal, stable pulp region, providing for firm precision pinch grips and precision handling of objects; and 3) asymmetric attachment of the flexor pollicis longus (FPL) tendon fibers, favoring PDP conjunct pronation. A proportionately larger size of the ulnar vs. radial ungual spine suggests differential loading intensity of the ulnar side of the proximal ungual pulp and supporting nail bed. Stresses at the distal interphalangeal joint are indicated by the presence of a sesamoid bone within the volar (palmar) plate, which also increases the length of the flexor pollicis longus tendon moment arm. Dissections of specimens from six nonhuman primate genera indicate that these human features are shared variably with individuals in other species, although the full pattern of features appears to be distinctively human. Humans share variably with these other species all metric relationships examined here. The new data identify a need to systematically review long-standing assumptions regarding the range of precision and power manipulative capabilities that might reasonably be inferred from morphology of the distal phalangeal tuberosity and from the FPL tendon insertion site on the PDP.

Animals↗

PubMed1987

Site-related variations in glycosaminoglycan content and swelling properties of bovine flexor tendon.

The presence of morphologically distinct tissues within the adult bovine deep flexor tendon presented a model which we examined for correlations between proteoglycan content and tissue swelling properties. The proximal portion which experiences only tensile forces contained low levels of glycosaminoglycan (0.2% glycosaminoglycan hexosamine as percentage of dry weight) that were evenly distributed throughout its length and thickness. Collagen accounted for 80% of tissue mass, and collagen fibers formed parallel arrays running longitudinal to the direction of tensile force. In equilibrium bulk swelling tests, the properties of proximal tissue were uniform throughout the tissue and typical of collagenous tissues in which the response to equilibration in low ionic strength buffers or acid pH is dominated by the collagen network. The anterior aspect of the distal deep flexor tendon articulates with the stiff paratendinous sheath and sesamoid bones and is subjected to compressive and frictional forces in addition to longitudinal tensile forces. Along this anterior surface and extending partially into the tendon is tissue that resembles fibrocartilage with collagen fibers organized as a random network. Greatest glycosaminoglycan hexosamine contents (2-3% of dry weight) were found in the distal surface layer, and large proteoglycans were concentrated at the site receiving direct compressive and frictional loads. Equilibrium bulk swelling tests on distal tissue showed that the articulating surface layer possessed unique material properties. Distal surface layers swelled when counter ions were washed from the tissue, whereas lowered pH had little effect on distal tissue volume. Swelling properties of distal tissue correlated directly with proteoglycan content and were similar to swelling properties of articular cartilage. These results suggest that the articulating layer of distal flexor tendon is adapted for a unique set of mechanical requirements and that an elevated proteoglycan content at the site of compressive and frictional forces contributes to meeting these functional needs.

Animals↗

PubMed1994

Transforming growth factor-beta stimulates retinoic acid-induced proteoglycan depletion in intact articular cartilage.

Cartilage-bearing sesamoid bones from the metacarpophalangeal joints of adult cows were cultured with retinoic acid for 1 week and allowed to recover in control medium for another 2 weeks. Retinoic acid decreased the proteoglycan synthesis of the cartilage to 33% of control values, and induced 26% loss of proteoglycans from the matrix. During recovery, the synthesis of proteoglycans returned to the control level but their content remained reduced. Transforming growth factor-beta (TGF-beta 1, 5 ng/ml) was added to the culture medium to stimulate the recovery. However, TGF-beta depressed the synthesis of proteoglycans and increased their loss to 61%. Only the large aggregating species, aggrecan, was lost from the matrix. The half-life of proteoglycans synthesized during recovery in control medium was 12.7 days, which was reduced to 8.7 days by TGF-beta. The proteoglycan half-life in control cartilage cultured without retinoic acid or TGF-beta was 33.8 days. Neither retinoic acid nor TGF-beta-induced changes in the hyaluronate content of the tissue. Aggrecans and small proteoglycans synthesized in the presence of TGF-beta were larger than those in controls. The synthesis of the small proteoglycans was stimulated 4.5-fold by TGF-beta, and their content was increased. The results show that TGF-beta can stimulate depletion of aggrecan in retinoic acid-treated cartilage. This indicates a catabolic function of TGF-beta in cartilage remodeling.

Aggrecans↗

PubMed1984

The painful accessory navicular.

The accessory navicular is usually considered a normal anatomic and roentgenographic variant. The term may refer to two distinct patterns. First, a sesamoid bone may be present within the posterior tibial tendon (Type 1); this is anatomically separate from the navicular. Second, an accessory ossification center may be medial to the navicular (Type 2). During postnatal development this is within a cartilaginous mass that is continuous with the cartilage of the navicular. At skeletal maturity the accessory center usually fuses with the navicular to form a curvilinear bone. The Type 2 pattern may be associated with a painful foot, particularly in the athletic adolescent, and should not be arbitrarily dismissed as a roentgenologic variant in the symptomatic patient. The clinical, radiologic, pathologic, and surgical findings in ten cases are reviewed. Roentgenographically the ossicle is triangular or heart-shaped. 99mTc MDP imaging may be of value when the significance of the ossicle is uncertain. Even when the roentgenographic variant is bilateral, increased radionuclide activity occurs only on the symptomatic side. Histologic examination of surgically excised specimens reveals inflammatory chondro-osseous changes in the navicular-accessory navicular synchondrosis compatible with chronic trauma and stress fracture. Nonsurgical treatment with orthotics or cast immobilization produces variable results and resection of the accessory navicular may be the treatment of choice.

Adolescent↗

PubMed1986

Metacarpophalangeal subluxation: locked finger.

The so-called locked finger is a rarely reported condition that can be easily recognized when its typical picture is borne in mind: painful locking of a finger, making it impossible to fully extend the metacarpophalangeal joint, and a lateral displacement of the extensor tendon at this level. Radiological findings may include abnormal shape of the metacarpal head, free intra-articular bodies, sesamoid bones at the volar plate level and degenerative changes in the metacarpophalangeal joint. There is consistently a previous history of repeated light manual effort. This condition generally affects men, aged 50 or older. Two of the three cases presented (three of the four affected fingers) were successfully treated by means of gentle manipulation under regional nerve blocking. The patient who refused treatment remains with a painless locked finger 1 year later. There has been no recurrence with either of the two manipulated patients (three fingers).

Finger Joint↗

PubMed1997

Can magnetization transfer magnetic resonance imaging follow proteoglycan depletion in articular cartilage?

In this study we determined the efficiency of magnetization transfer magnetic resonance imaging (MT-MRI) to differentiate native and enzymatically degraded cartilage, using bovine sesamoid bones from the metacarpophalangeal joint as a model system. Gradual proteoglycan (PG) depletion was achieved by increasing incubation periods with testicular hyaluronidase. For native cartilage a Ms/Mo ratio of 0.303 +/- 0.09 (mean +/- SEM) was measured. Biochemically determined PG diminution up to 50% correlated strongly (r = 0.953) with changes in the Ms/Mo ratio. Further PG loss is not reflected in an equally drastic Ms/Mo increase, whereas subsequent treatment of PG-depleted cartilage samples with collagenase led to an additional rise in the Ms/Mo ratio. Proteoglycan depletion and the beginning destruction of the collagen structure were also assessed histochemically. Our study confirms that collagen contributes to the baseline MT effect observed in articular cartilage. However, the changes in the MT ratio in gradually PG-depleted cartilage with a largely intact collagen network indicate that PG contributes to the MT effect as well. Therefore MT-MRI might become a sensitive technique for the monitoring of subtle degradational changes in articular cartilage, the still inaccessible process in osteoarthritis.

Animals↗

PubMed2002

[Ultrasound diagnosis in knee and foot trauma].

Subsequent to clinical and radiologic examination, ultrasonography is an important diagnostic method in knee and foot trauma, especially to assess pathologic conditions of the periarticular soft tissue. The main indications for ultrasonographic assessment of the knee region are fluid conglomerations, injuries of tendons, ligaments, and muscles, and vascular diagnosis. The indications for ultrasonography in the foot region are diagnosis of foreign bodies, dislocation of the peroneal tendons, lesions to the flexor and extensor tendons, and osseous capsular and ligamentous avulsions. Changes of the soft tissues include articular effusion, fluid conglomeration, ossification, and vascular lesions. Fractures involve the base of the fifth metatarsal, navicular and sesamoid bones, and epiphysiolysis. Rare indications are the search for free articular bodies and free air and the depiction of cartilaginous lesions and fractures of the knee region.

Foot Injuries↗

PubMed1996

[Resection arthroplasty in the treatment of hallux valgus].

Sixty-six feet operated on for hallux valgus in 1984 were reviewed. Keller-Brandes' operation was performed in all cases, together with Lelièvre's "fibrous cerclage" and flexor hallucis longus tendon anchoring to the sesamoid pad, as described by A. Viladot. In most cases, satisfactory clinical correction was achieved and the patients could wear standard shoes. More than half of the cases presented partial limitation of movement at the first metatarsophalangeal joint; however, flexion power of the big toe was preserved, and the range of motion was wide enough to allow a painless and limp-free gait. Radiologically, good correction of the angle between the first and second metatarsals and the metatarsophalangeal angle was obtained, but all cases presented proximal displacement of sesamoid bones. A baropodometric study showed that the toe-off phase of the gait does not change after this operation. In our series, central metatarsalgia was present in 17 feet; however, it did not compromise the functional result and was easily relieved with orthopaedic devices. Four feet showed radiographic images, suggesting necrosis of the first metatarsal head; all four were asymptomatic. The only case that required reoperation was the one that developed hallux varus deformity. The Keller-Brandes-Lelièvre-Viladot procedure is still a simple and effective method for the surgical treatment of hallux valgus in elderly people with osteoarthritis at the first metatarsophalangeal joint.

Adult↗

PubMed2005

Bony and cartilaginous anatomy of the patellofemoral joint.

The patella as the largest sesamoid bone of the human body forms the patellofemoral joint with the patellar groove of the femur. The patellofemoral joint is a complex articulation with high functional and biomechanical requirements. Several anatomical variants of both patella and the trochlea exist. Multiple clinical problems of the knee may be caused by anatomical and physiological abnormalities of this joint. Exact knowledge about the anatomy, the biomechanics and the function of the patellofemoral joint is therefore required to understand its wide range of pathology.

Bone Diseases, Developmental↗

PubMed2004

Arthroscopic treatment of a ganglion of the first metatarsophalangeal joint.

The case of a ganglion that had developed around the first metatarsophalangeal (MTP) joint and in which several other therapeutic approaches were unsuccessful was treated using an arthroscopic assisted procedure. During MTP arthroscopy, we found that the pedicle of the tumor was attached to the interior of the joint, and the lesion was successfully extirpated. Communication with the cyst was found on the medial side of the lateral sesamoid bone, which coincided with the rounded portion of the first MTP joint at the sole, where stress is exerted repeatedly while walking. Thus, the intracystic fluid could not return to the intra-articular space. Instead the cyst gradually extended to the extra-articular tissue, where it was relatively loosely connected. Researchers suspect that a ganglion originally develops through repeated mechanical stress; the lesion is constantly under pressure because of the weight bearing on it. Because of a higher pressure within the MTP joint, the communicating opening acts as a valve.

Aged↗