Ligament Insertion Research Articles

Development of a Preliminary Ultrasonographic Enthesitis Score in Psoriatic Arthritis - GRAPPA Ultrasound Working Group.

To assess the performance of various sonographic elemental entheseal lesions in distinguishing between psoriatic arthritis (PsA) and controls to inform the development of a novel sonographic enthesitis score for PsA. A total of 100 age- and sex-matched individuals (50 PsA and 50 controls) were evaluated. Eleven entheseal sites were scanned bilaterally according to a standardized protocol by 2 sonographers. Based on the Outcome Measures in Rheumatology (OMERACT) definition of sonographic enthesitis, the following lesions were assessed: structural entheseal changes (hypoechogenicity), thickening, bone erosion, enthesophytes, calcification, and Doppler signal, in addition to bursitis and bone irregularities. The images were read by 2 readers blinded to the clinical information. A series of logistic regression models were used to find the optimal combination of entheseal sites and elementary lesions that distinguished PsA from controls. Mean age was 55 ± 10 years (59% males). The optimal model that distinguished PsA from controls included 5 elementary lesions (enthesophytes, Doppler signal, erosions, thickening, and hypoechogenicity) and 6 entheseal sites (patellar ligament insertions into the distal patella and tibial tuberosity, Achilles tendon and plantar fascia insertions into the calcaneus, common extensor tendon insertion into lateral epicondyle, and supraspinatus insertion into the superior facet of the humerus). The area under the receiver-operating characteristic curve for this model was 0.93 (95% CI 0.88-0.98). We identified potential elemental ultrasonographic abnormalities and entheseal sites that could distinguish PsA and controls. This information will contribute to the development of a new sonographic score for assessment of enthesitis in patients with PsA.

Le fratture articolari ed extra-articolari del ginocchio

Joint fractures of the knee include epiphyseal detachments of the distal femur and proximal tibia (types 3 and 4 according to Salter-Harris). Extra-articular fractures include: avulsion of the tibial spines, detachment of the anterior tuberosity and patellar fractures. Fractures involving the distal femoral and proximal tibial epiphysis are relatively infrequent but may lead to long-term complications owing to the formation of post-traumatic bone bridges. Unless the fracture is composed, surgical treatment is always indicated. Avulsion fractures of the tibial spines occur as a result of a chondro-epiphyseal detachment of the insertion of the cruciate ligaments (predominantly the anterior one). They are infrequent injuries (3 per 100,000 cases per year, 2% of all knee injuries). Accurate diagnosis and appropriate treatment prevent unfortunate outcomes. Adolescent tibial tubercle fractures are uncommon, high-energy injuries sometimes combined with patellar tendon rupture; they represent a frequently missed diagnosis. Open reduction/internal fixation is generally required. Patellar fractures are caused by direct trauma (primary osseous fractures) or by an eccentric load during extension of the knee (sleeve and avulsion fractures). Most fractures require open reduction/internal fixation. The complication rate is low but late reconstruction of missed injuries may result in an extensor deficit.

Accessory cavitated uterine mass: MRI features and surgical correlations of a rare but under-recognised entity.

To describe MRI features of accessory cavitated uterine mass (ACUM) with surgical correlations. Eleven young women with an ACUM at pathology underwent preoperative pelvic MRI. Two experienced radiologists retrospectively analysed MR images in consensus to determine the lesion location within the uterus, its size, morphology (shape and boundaries), and structure reporting the signal and enhancement of its different parts compared to myometrium. The presence of an associated urogenital malformation or other gynaecological anomaly was reported. MRI features were correlated with surgical findings. All 11 lesions were well correlated with surgical findings, lateralised (seven were left-sided), and located under the horn and the round ligament insertion. Nine were located within the external myometrium, bulging into the broad ligament. Two were extrauterine, entirely located within the broad ligament. On MRI, the mean size was 28 mm (range 17-60 mm). Nine lesions were round-shaped, two were oval; all had regular boundaries. At surgery, the ACUM were not encapsulated but were possible to enucleate. On MRI, all lesions were well defined and showed a central haemorrhagic cavity surrounded by a regular ring (mean thickness, 5 mm) which had the same signal compared to the junctional zone. ACUM was isolated in all women, without urogenital malformation, adenomyosis or deep endometriosis. On MRI, ACUM was an isolated round accessory cavitated functional non-communicating horn-like aspect in an otherwise normal uterus. MRI may facilitate timely diagnosis and appropriate curative fertility-sparing laparoscopic resection. • ACUM is rare, with delayed diagnosis in young women with severe dysmenorrhoea. Pelvic MRI facilitates timely diagnosis and appropriate curative fertility-sparing laparoscopic resection. • Quasi-systematically located under the uterine round ligament insertion, ACUM may be intramyometrial and/or in the broad ligament. • On MRI ACUM resemble a non-communicating functional accessory horn within a normal uterus; the mass, most often round-shaped, had a central haemorrhagic cavity surrounded by a regular ring which had the same low signal compared to the uterine junctional zone.

Vertebral lesions in a titanosaurian dinosaur from the Lower-Upper Cretaceous of Brazil

In this paper we describe macroscopically two types of bone lesions on a caudal vertebra of an indeterminate titanosaur recovered from the Lower-Upper Cretaceous (Albian-Cenomanian) Açu Formation in the Potiguar Basin, Brazil. The first type of lesion corresponds to cystic lesions on cranial and caudal joint surfaces of the vertebral body, which are identified as subchondral cysts. The second type of lesion corresponds to an irregular bone overgrowth located on longitudinal ligament insertion points. This ossification can be associated with an axial spondyloarthropathy or diffuse idiopathic skeletal hyperostosis (DISH). Bone overgrowth on vertebrae is well documented in the dinosaur fossil record, whereas this is only the second case recorded of subchondral cysts.

Radiographic and Anatomic Landmarks of the Major Knee Ligaments.

* A thorough understanding of the anatomic and radiographic landmarks is imperative for reconstructing the native insertions of the major ligaments around the knee.* The 2 cruciate ligaments, the anterior cruciate ligament and the posterior cruciate ligament, each have osseous intra-articular landmarks that separate the ligament bundles and can be used to guide accurate reconstructions.* The 2 collateral ligaments, the medial collateral ligament and the lateral collateral ligament (LCL), each have femoral insertions close to their respective epicondyles, and because of the location of their distal insertions, the ligaments gradually lose tension as the knee is flexed.* The anterolateral ligament is a controversial structure that may have a role in controlling knee internal rotation because of its femoral insertion just proximal and posterior to the LCL and its tibial location just distal to the joint line between Gerdy’s tubercle and the fibular head.* As the primary soft-tissue restraint against lateral patellar instability, the medial patellofemoral ligament inserts on the proximal and posterior aspect of the medial femoral condyle and attaches to the proximal third of the patella, with variable attachments to the medial aspect of the quadriceps tendon.

Anatomy of the Insertion of the Posterior Inferior Tibiofibular Ligament and the Posterior Malleolar Fracture

Category: Ankle Introduction/Purpose: The treatment of posterior malleolar fractures is developing. Our previous study on the anatomy of the posterior malleolar fracture identified only 49% of rotational push off fractures of the posterior malleolus had syndesmotic instabilities. This was against general thinking that fixation of such a fragment would stabilize the syndesmosis. Our aim in this study was to identify the extent of the posterior inferior tibiofibular ligament insertion on the posterior tibia and its relation to push off fractures. Methods: We examined 10 cadaveric lower limbs that had been preserved for dissection at the Human Anatomy and Resource Centre at Liverpool University in a solution of formaldehyde. The lower limbs were carefully dissected to identify the ligamentous structures on the posterior aspect of the ankle. Results: In all specimens, the tibial insertion of the PITFL encompassed 1/3 of the distal posterior tibia. In addition, the posterior intermalleolar ligament inserted onto the posterior tibia just medial to the tibialis posterior groove. Thus a rotational push off fracture would only cause syndesmotic injury if greater than a 3 rd of the posterior tibia was injured or occurred in combination with a ligamentous injury. This is in keeping with the clinical findings of only 49% syndesmotic instabilities with Haraguchi type 1 posterior malleolar fractures. Conclusion: Haraguchi type 1 posterior malleolar fractures (less than a 3 rd of the width of the posterior tibia) are unlikely to cause syndesmotic instabilities without the addition of a ligamentous injury.

Identification of the Medial Column Line collapse variation is Crucial in Flat Foot Management

Category: Midfoot/Forefoot Introduction/Purpose: The incompetence of both dynamic and static structures in the foot is responsible for acquired pes planus deformity. The aim of this study was to identify the anatomical location of the midfoot break in symptomatic pes planus deformity, and its relationship with other pes planus radiographic foot measurements. Methods: We completed the radiographic evaluation of 75 feet diagnosed with symptomatic pes planus. The break in the medial column line (Meary’s line) was measured on the lateral radiograph at the intersection of the anatomical axis of the talus and the first metatarsal. Pes planus measurements were performed on each the weight-bearing AP and lateral radiographs, including talonavicular coverage angle, talar – first/ second metatarsal angle, talar uncoverage, talocalcaneal angle, Meary’s angle line break, calcaneal and talar inclination, talocalcaneal angle, cuneiform - metatarsal, tarsal joints angles and distances. Due to Gaussian distribution, unpaired t-test and ANOVA tests were used. Results: The medial column line collapse was at the talonavicular joint in 77.3%, naviculocuneiform in 20%, and cuneiform metatarsal in 2.6%. The line angle severity was proportional to the talonavicular coverage angle and talar uncoverage (p 0.001, R2 0.4915 and P 0.003, R2 0.223). On comparison of the 3 line-break groups, the talocalcaneal angle was significantly higher when the line break was at talonavicular joint (P 0.001) although Meary’s angle was not significantly more severe. Conclusion: The apex of the medial column collapse occurs not only at the talonavicular joint but also distal to the spring ligament and tibialis posterior insertion. Foot abduction increases with the increase in the line collapse regardless of the breaking point. Talus flexion is worse if the arch collapse is at the talonavicular joint, suggesting incompetency of the spring ligament. Assessing the apex of deformity is essential to decide the correct operative strategy.

Effect of McGlamry Elevator Placement on the Plantar Plate Origin

Category: Lesser Toes Introduction/Purpose: Lesser metatarsal phalangeal (MTP) joint plantar plate tears have been implicated in a variety of lesser toe pathologies, and plantar plate repair (PPR) through a dorsal approach has become increasingly popular as a treatment of lesser toe deformities and lesser MTP instability. With the aid of a McGlamry elevator, releasing the collateral ligaments and micro-suture passing techniques, the plantar plate is repaired under direct visualization. While this approach is seen as a reliable alternative, the consequence of this technique on local MTP joint anatomy is not yet well understood. The purpose of this study is to describe the proximal plantar plate attachment and to quantify the amount of soft tissue disruption of the lesser toe MTP joint anatomy with insertion of a McGlamry elevator. Methods: Fresh frozen human cadaveric feet were dissected, and the proximal plantar plate attachment of the second, third, and fourth toe MTP joints (n=6) were examined, focusing on the relationship of structures connecting the distal metatarsal shaft and head to the plantar plate. The accessory collateral ligament insertions and proximal plantar plate attachments were measured using digital calipers. Next, the second, third, and fourth rays (n=12) of separate fresh frozen cadaveric specimens were isolated. An 11mm McGlamry elevator was then inserted in standard surgical fashion in both a more shallow (limited exposure) and deeper (greater exposure) position. Using mini C-arm fluoroscopy, radiographs were taken in both positions, and the depth of insertion along the metatarsal was measured. Results: The proximal plantar plate attachment to the metatarsal is most robust just proximal to the lateral articular margin and this attachment extends an average of 10.42mm (SD= 2.71mm) proximally along the metatarsal neck and shaft. In addition there are stout proximal plantar plate attachments at the bilateral insertion sites of the accessory collateral ligament (ACL) which are thick and broad with an average insertion length of 9.01mm (SD=1.35mm). Insertion of a McGlamry elevator resulted in stripping of the distal plantar soft tissues over an average of 21.58% of the total metatarsal length (SD=4.43%) for shallow placement and 34.87% (SD=4.40%) for deep placement with a significant difference of 7.96% between the two positions (p<.00001). Conclusion: Current techniques of plantar plate repair through a dorsal approach require releasing collateral ligaments and proximal stripping of the plantar plate from the metatarsal for adequate visualization. We suggest that this significantly destabilizes the metatarsal from the plantar plate as it strips approximately the distal most one third of the metatarsal including all major proximal plantar plate attachments to the metatarsal. As surgical techniques continue to evolve and improve, surgeons should consider avoiding the placement of a McGlamry elevator as this can destabilize the proximal attachment of the plantar plate to the metatarsal.

The Plantar Support of the Navicular-Cunieform Joint

Category: Midfoot/Forefoot Introduction/Purpose: Weight-bearing radiographic analysis of pes planus deformities shows, with varying degree of severity, a break in Meary’s line, uncovering of the talar head and an increase in talar-first metatarsal angle. Work by Alsousou (BOFAS 2016) has shown the break in Meary’s line to occur not only at the talonavicular joint (2/3rds of cases) but also at the navicular-cuneiform joint (1/3 rd of cases), distal to the spring ligament and reported posterior tibial tendon insertion. There are currently no anatomical studies analysing the medial longitudinal arch distal to the spring ligament insertion. We aimed to examine this area and assess the anatomy supporting the distal medial longitudinal arch. Methods: We examined 11 cadaveric lower limbs that had been preserved for dissection at the Human Anatomy and Resource Centre at Liverpool University, in a solution of formaldehyde. The lower limbs were carefully dissected to identify the plantar aspect of the medial longitudinal arch Results: In all specimens, the posterior tibial tendon inserted into the plantar medial aspect of the navicular with separate slips to the intermediate and lateral cuneiform. Following insertion, on the navicular, a tendon-like structure extended from this navicular insertion point to the medial cuneiform. This tendon-like structure is statically inserted between the navicular and medial cuneiform allowing the pull of tibialis posterior to act on the navicular and medial cuneiform in tandem. The average width of this ligament (15.2 mm) is much greater than that of the tibialis posterior tendon (9.5 mm). A separate smaller plantar ligament is also present between the navicular and medial cuneiform. Conclusion: The posterior tibialis tendon inserts into the navicular, and what is likely an anthropological remnant, extends onto the medial cuneiform as the navicular cuneiform ligament. This provides a static restraint between two bony insertions and increases the lever arm of the posterior tibial tendon. The major support of the distal aspect of the medial longitudinal arch (i.e. the navicular-cuneiform joint) is provided by the substantial navicular cuneiform ligament.

Histological study of the posterior cruciate ligament femoral insertion

ObjectivesTo describe the microscopic anatomy of the posterior cruciate ligament femoral insertion in order to identify and establish differences between the direct and indirect insertions of this ligament. MethodsTen cadaveric knees were used for this study. The posterior cruciate ligament femoral insertion was observed microscopically. Hematoxylin and eosin staining was performed to observe the morphology of the posterior cruciate ligament insertion. Alcian blue staining was performed to determine the location of the cartilage matrix and better assist in the observation and differentiation between direct and indirect insertions. ResultsThe direct insertion was observed to be a more complex structure than the indirect insertion because it showed four different histological layers (ligament, uncalcified fibrocartilage, calcified fibrocartilage, and bone). Chondrocytes were observed in the uncalcified and calcified fibrocartilage layers. It was observed that the indirect insertion was composed of two layers in which the ligament was anchored directly to the bone by collagen fibers. Indirect insertion was located in the marginal region of the posterior cruciate ligament between the direct insertion and the anterior articular cartilage. ConclusionThrough histological analysis, it was demonstrated that the indirect insertion was adjacent to the anterior articular cartilage and presents a histological pattern where the collagen fibers insert directly into the bone (two-layer insertion). The direct insertion is posterior to the indirect insertion and has four histologically distinct layers.

Descriptive anatomy of the anterior cruciate ligament femoral insertion

ObjectiveTo evaluate the morphology of the anterior cruciate ligament (ACL) femoral insertion in order to describe its anatomical features and insertion site location, with the aim of verifying if the ACL femoral insertion has individual characteristics and to provide information for appropriate femoral tunnel placement on anatomic ACL reconstruction. MethodsSixteen knees obtained from amputations were studied. The ACL femoral bundles and insertion shape were observed macroscopically, and the ligaments insertion length and thickness were measured with a digital caliper. The distances between the limits of the ligament to the articular cartilage, and the measurement of the area of insertion were checked using ImageJ software. ResultsThe ACL femoral insertion site was eccentric, closer to the deep condyle cartilage. In ten knees (62.5%), the ACL femoral insertion was oval; the mean length of the insertion was 16.4mm, varying from 11.3 to 19.3mm, the mean thickness varied from 7.85 to 11.23mm, and the mean area of the insertion was 99.7mm2, varying from 80.9 a 117.2mm2. The mean distances between the limits of the ligament to the superficial, deep, and inferior articular cartilage were 9.77±1.21, 2.60±1.20, and 1.86±1.15mm, respectively. ConclusionThere was a 30% to 40% difference between the minimum and maximum results of measurements of ACL femoral insertion length, thickness, and area demonstrating an important individual variation. The insertion site was eccentric, closer to the deep cartilage of the lateral femoral condyle.

Radiographic assessment of the proximal tibial angles in dogs and cats with and without cranial cruciate ligament rupture

ABSTRACT: The influence of the proximal tibial angles in the cranial cruciate ligament (CCL) rupture in dogs is still controversial, and little is known regarding this topic in cats. The aim of this study was to evaluate and compare the angles of the proximal portion of the tibia in dogs and cats with and without CCL rupture. Retrospective and prospective radiographs of the stifle joints were obtained and divided into four groups. Group 1 was composed of 70 stifle joint images of dogs without orthopedic disorders (healthy dogs), group 2 had 70 stifle joint images of dogs with CCL rupture, group 3 had 50 stifle joint images of cats without orthopedic disorders (healthy cats) and group 4 had 25 stifle joint images of cats with CCL rupture. Radiographs were taken with the stifle joint in the mediolateral projection, positioned at the angle of hind limb support. Between the two groups of dogs evaluated, the dogs with CCL rupture had statistically greater tibial plateau angle (TPA) compared with healthy dogs. No difference was shown in relation to the TPA between healthy cats and cats with CCL rupture. In relation to the patellar ligament angle by tibial plateau method the values for the healthy dogs were significantly higher than those for the CCL ruptured dogs. Similarly, healthy cats had significantly higher mean values than cats with CCL rupture. In the patellar ligament angle by common tangent method there was no significantly difference between the two groups of dogs. Between the two groups of cats, animals with CCL rupture had statistically higher mean values than healthy cats. In general, the groups of dogs showed higher mean values than the groups of cats. For the patellar ligament insertion angle (PLIA) healthy dogs showed a significantly higher mean than dogs with CCL rupture. There was no significant difference between the groups of cats. In conclusion, the TPA and the PLIA possibly influence the etiology of CCL rupture in dogs but not in cats. The low patellar ligament angle measured by common tangent method may favorably influence the reduced incidence of CCL rupture in cats.

Osteology of Batrachuperus londongensis (Urodela, Hynobiidae): study of bony anatomy of a facultatively neotenic salamander from Mount Emei, Sichuan Province, China.

The Longdong Stream Salamander Batrachuperus londongensis, living in a mountain stream environment at Mt. Emei in Sichuan Province, China, represents a rare species that is facultatively neotenic in the family Hynobiidae. Although the species has been known to science for some 40 years since its initial discovery in the late 1970s, anatomical details of its osteology remain poorly understood and developmental information is still lacking for the species. This study (1) provides a detailed osteological account of B. londongensis based on micro-CT scanning and clearing and staining of multiple specimens from the type locality; (2) provides a discussion of intraspecific variation related to life-history differences; and (3) presents a discussion on limb features related to morphological evolution of limb patterns correlative with ecological adaptation to mountain stream environments. Osteological comparisons with congeneric species has led to recognition of several diagnostic features that are unique to B. londongensis, including: vomers widely separated from one another, lacking a midline contact; presence of uncommon perichondral ossification of the ascending process of the palatoquadrate as part of the suspensorium; and presence of a prominent posterodorsal process of the scapular blade, which serves as a ligamentous insertion of the levator muscle of the scapula. In addition, some but not all neotenic individuals retain the palatine as a discrete element, indicative of its delayed absorption after sexual maturity. Postmetamorphic and neotenic individuals are strikingly different in the complexity of hyobranchial structures. Neotenes display a high degree of ossification of hyobranchial elements, tend to increase ossification of both hypobranchial I and ceratobranchial I during aging, and retain fully ossified ceratobranchial III and IV; in contrast, these elements remain entirely cartilaginous or are totally lost by resorption in postmetamorphic individuals. In addition, all postmetamorphic forms display an inverted “T”-shaped basibranchial II, whereas neotenes show transformation from a “fork”-shaped to the “T”-shaped configuration after sexual maturity. B. londongensis displays a mosaic of apomorphic and plesiomorphic states in its limb ossifications: presence of a single centrale element in both the manus and pes is a derived condition in Hynobiidae and other families as well, whereas retention of a postminimus in the pes is obviously plesiomorphic within Urodela. Reduction in number of digits from five to four in the pes and possession of a cornified sheath covering the terminal phalanges are also derived features shared with some but not all mountain stream salamanders that are adapted to a similar type of environment.

Peroneal Nerve Function and Knee Stability after Resection Giant Cell Tumour of Proximal Fibula, A Serial Case

Abstract: Giant-cell Tumour (GCT ) is a benign Tumour, locally aggressive neoplasm which is composed of sheets of neoplastic oviod mononuclear cells uniformly distributed large, osteoclast like giant cell. Incidence GCT of proximal fibula is rare. Peroneal nerve function and stability of knee joint must be considered at the proximal fibula GCT. In 2017 we found three cases of GCT of the proximal fibula in the outpatient clinic Saiful Anwar General Hospital. All three of these patients had a confirmed GCT of proximal fibula which planned for Tumour resection, peroneal nerve presevation and LCL ligament reconstruction. This is study of three patients with GCT of proximal fibula was confirm with Clinical Pathological Confrence (CPC). All of patient had presented of lump, slowly growing pain in lateral side of knee, limping when they walk and numbness in dorsal side of foot. One patient cannot dorsoflexion of ankle. We evaluated a peroneal nerve function and stability of knee after operation and one year after resection of tumour. All patient had occurred peroneal nerve lesion with no instability of knee post operatively. Two patient had complaint with numbness in dorsal side of foot and weakness ankle dorsoflexion and after one year both of patient had improved ankle dorsoflexion but still numbness in dorsal side of foot. One patient still complaining numbness in dorsal side of foot and weakness ankle dorsoflexion post operation and one year after operation. There is no LCL ligament instability in all of patient post operation and one year after operation. The peroneal nerve function and LCL ligament stability must consider when facing benign tumours in proximal fibula such as giant cell tumour proximal fibula. These resections result in an unavoidable loss of knee stability because of resecting the lateral collateral ligament (LCL) insertion site on the fibular head. Based on the literature, the incidence rate of postoperative peroneal nerve palsy ranges from 3% to 57%. Giant cell tumour in proximal fibula is rare and require wide excision with intraarticular resection of the proximal tibiofibular join. We must consider about peroneal nerve function and LCL ligament stability during resection of GCT proximal fibula. Keywords: Giant Cell Tumour Proximal Fibula, Peroneal Nerve function, LCL Ligament stability

Classifications in Brief: Regan-Morrey Classification of Coronoid Fractures.

Classifications in Brief: Regan-Morrey Classification of Coronoid Fractures.

Quantitative Assessment of the Coracoacromial and the Coracoclavicular Ligaments With 3-Dimensional Mapping of the Coracoid Process Anatomy: A Cadaveric Study of Surgically Relevant Structures

To perform a quantitative anatomic evaluation of the (1) coracoid process, specifically the attachment sites of the conjoint tendon, the pectoralis minor, the coracoacromial ligament (CAL), and the coracoclavicular (CC) ligaments in relation to pertinent osseous and soft tissue landmarks; (2) CC ligaments' attachments on the clavicle; and (3) CAL attachment on the acromion in relation to surgically relevant anatomic landmarks to assist in planning of the Latarjet procedure, acromioclavicular (AC) joint reconstructions, and CAL resection distances avoiding iatrogenic injury to surrounding structures. Ten nonpaired fresh-frozen human cadaveric shoulders (mean age 52years, range 33-64years) were included in this study. A 3-dimensional coordinate measuring device was used to quantify the location of pertinent bony landmarks and soft tissue attachment areas. The ligament and tendon attachment perimeters and center points on the coracoid, clavicle, and acromion were identified and subsequently dissected off the bone. Coordinates of points along the perimeters of attachment sites were used to calculate areas, whereas coordinates of center points were used to determine distances between surgically relevant attachment sites and pertinent bony landmarks. The CAL had a single consistent acromial attachment (mean area 77mm [51.9, 102.2]) and then bifurcated into 2 bundles, anterior and posterior, that separately inserted on the lateral aspect of the coracoid. The footprint areas were 54.4mm2 [31.7, 77.2] and 30.6mm2 [23.4, 37.7] for the anterior and posterior CAL bundles, respectively. These anterior and posterior bundles attached 10.6mm [8.4, 12.9] and 24.8mm [12.3, 27.4] medial and proximal to the apex of the coracoid process, respectively. The minimum distance between the coracoid apex and the trapezoid ligament was 25.1mm [22.1, 28.1] and was noted to be different in males (28.1mm [25.1; 31.2]) and females (22.0mm [18.2, 25.9]). The most lateral insertion of the CC ligaments on the clavicle the AC joint was 15.7mm [13.1, 18.3]. The distance between the most medial to the most lateral point of the CC ligaments on the clavicle was 25.6mm [22.3, 28.9], which accounted for 18.2% [15.8, 20.6] of the clavicle length. In contrast to previous findings, 2 different coracoid attachments (anterior and posterior bundles) of the CAL were consistently identified in all specimens. Moreover, a coracoid osteotomy for a bone graft for the Latarjet procedure should be performed at less than 28.1/22mm from the apex of the coracoid in male/female patients, respectively. The CC ligaments' attachments on the clavicle were located 15.7mm from the AC joint, which should be considered for reconstruction. During the Latarjet technique, to maintain the integrity of the CC ligaments, precise knowledge of differences between male and female anatomy is necessary during a coracoid osteotomy. Furthermore, when reconstructing the AC joint, the distance from the lateral aspect of the clavicle and the size of the attachments areas should be considered to better replicate the native anatomy.

Aberrant TGF-β activation in bone tendon insertion induces enthesopathy-like disease.

Enthesopathy is a disorder of bone, tendon, or ligament insertion. It represents one-fourth of all tendon-ligament diseases and is one of the most difficult tendon-ligament disorders to treat. Despite its high prevalence, the exact pathogenesis of this condition remains unknown. Here, we show that TGF-β was activated in both a semi-Achilles tendon transection (SMTS) mouse model and in a dorsiflexion immobilization (DI) mouse model of enthesopathy. High concentrations of active TGF-β recruited mesenchymal stromal stem cells (MSCs) and led to excessive vessel formation, bone deterioration, and fibrocartilage calcification. Transgenic expression of active TGF-β1 in bone also induced enthesopathy with a phenotype similar to that observed in SMTS and DI mice. Systemic inhibition of TGF-β activity by injection of 1D11, a TGF-β-neutralizing antibody, but not a vehicle antibody, attenuated the excessive vessel formation and restored uncoupled bone remodeling in SMTS mice. 1D11-treated SMTS fibrocartilage had increased proteoglycan and decreased collagen X and matrix metalloproteinase 13 expression relative to control antibody treatment. Notably, inducible knockout of the TGF-β type II receptor in mouse MSCs preserved the bone microarchitecture and fibrocartilage composition after SMTS relative to the WT littermate controls. Thus, elevated levels of active TGF-β in the enthesis bone marrow induce the initial pathological changes of enthesopathy, indicating that TGF-β inhibition could be a potential therapeutic strategy.

Extension of knee immobilization delays recovery of histological damages in the anterior cruciate ligament insertion and articular cartilage in rabbits

[Purpose] To investigate the influence of knee immobilization period on recovery of histological damages in the anterior cruciate ligament (ACL) insertion and articular cartilage in rabbits. This knowledge is important for determining the appropriate rehabilitation approach for patients with ligament injuries, fracture, disuse atrophy, and degenerative joint disease. [Materials and Methods] Forty-eight male Japanese white rabbits were divided equally into the remobilization and control groups. The remobilization group had the right knee surgically immobilized, and was divided equally into four subgroups according to the duration of immobilization (1, 2, 4 and 8 weeks). After the immobilization was removed, the rabbits moved freely for 8 weeks. The control group underwent sham operation and followed the same time course as the remobilization group. The chondrocyte apoptosis rate and chondrocyte proliferation rate in the ACL insertion and articular cartilage were analyzed after remobilization. [Results] In the ACL insertion, the remobilization group had a higher chondrocyte apoptosis rate than the control group after 8 weeks of immobilization, and a lower chondrocyte proliferation rate than the control group after 4 and 8 weeks of immobilization. In the articular cartilage, the remobilization group had a lower chondrocyte proliferation rate than the control group after 8 weeks of immobilization. After 8 weeks of remobilization, the ACL insertion and articular cartilage are not completely recovered after 4 and 8 weeks of immobilization, respectively. [Conclusion] Our results suggest that 8 weeks of remobilization will result in recovery of the ACL insertion after 2 weeks of knee immobilization, and recovery of the articular cartilage after 4 weeks of knee immobilization. If 8 weeks of immobilization occurs, a remobilization duration of more than 8 weeks may be necessary.

The diagnosis and treatment of tibial intercondylar chondroblastoma

OBJECTIVES:To investigate the diagnosis and treatment of tibial intercondylar chondroblastoma.METHODS:We retrospectively analyzed the diagnosis and treatment of 12 patients with tibial intercondylar chondroblastoma admitted to the orthopedics department from May 2011 to February 2016; among them were 4 males and 3 females aged 10-19 years, with an average age of 15.7 years. Tibial intercondylar chondroblastoma was on the left and right side in 7 and 5 cases, respectively. The preoperative average Lysholm score of the knee joint was 68 (42-87). A posteromedial approach was applied in all cases. The incisions were approximately 5-8 cm in length. Complete curettage and inactivation were performed after fenestration, and allogeneic bone grafts were transplanted. Then, the posterior cruciate ligament insertion was fixed with 5.0 suture anchors. All patients were followed up with regularly to monitor for tumor recurrence, observe bone graft healing, and reassess the Lysholm score of the knee.RESULTS:Patients were followed for 7-55 months, and the median follow-up time was 19 months. One patient experienced tumor relapse 4 months after the operation. Incision, inactivation and cementation were performed. Then, the bone was fixed with anchors. In the other 11 patients, the bone graft healed over an average period of 6.2 months (4-10 months), with good functional recovery postoperatively. The average postoperative Lysholm score of the knee was 91 (81-95).CONCLUSION:Tibial intercondylar chondroblastoma has unique clinical and imaging characteristics and can effectively be treated by curettage followed by the inactivation, transplantation and fixation of allogeneic bone grafts with suture anchors through a posteromedial approach.

Femoral Component External Rotation Affects Knee Biomechanics: A Computational Model of Posterior-stabilized TKA.

The correct amount of external rotation of the femoral component during TKA is controversial because the resulting changes in biomechanical knee function associated with varying degrees of femoral component rotation are not well understood. We addressed this question using a computational model, which allowed us to isolate the biomechanical impact of geometric factors including bony shapes, location of ligament insertions, and implant size across three different knees after posterior-stabilized (PS) TKA. Using a computational model of the tibiofemoral joint, we asked: (1) Does external rotation unload the medial collateral ligament (MCL) and what is the effect on lateral collateral ligament tension? (2) How does external rotation alter tibiofemoral contact loads and kinematics? (3) Does 3° external rotation relative to the posterior condylar axis align the component to the surgical transepicondylar axis (sTEA) and what anatomic factors of the femoral condyle explain variations in maximum MCL tension among knees? We incorporated a PS TKA into a previously developed computational knee model applied to three neutrally aligned, nonarthritic, male cadaveric knees. The computational knee model was previously shown to corroborate coupled motions and ligament loading patterns of the native knee through a range of flexion. Implant geometries were virtually installed using hip-to-ankle CT scans through measured resection and anterior referencing surgical techniques. Collateral ligament properties were standardized across each knee model by defining stiffness and slack lengths based on the healthy population. The femoral component was externally rotated from 0° to 9° relative to the posterior condylar axis in 3° increments. At each increment, the knee was flexed under 500 N compression from 0° to 90° simulating an intraoperative examination. The computational model predicted collateral ligament forces, compartmental contact forces, and tibiofemoral internal/external and varus-valgus rotation through the flexion range. The computational model predicted that femoral component external rotation relative to the posterior condylar axis unloads the MCL and the medial compartment; however, these effects were inconsistent from knee to knee. When the femoral component was externally rotated by 9° rather than 0° in knees one, two, and three, the maximum force carried by the MCL decreased a respective 55, 88, and 297 N; the medial contact forces decreased at most a respective 90, 190, and 570 N; external tibial rotation in early flexion increased by a respective 4.6°, 1.1°, and 3.3°; and varus angulation of the tibia relative to the femur in late flexion increased by 8.4°, 8.0°, and 7.9°, respectively. With 3° of femoral component external rotation relative to the posterior condylar axis, the femoral component was still externally rotated by up to 2.7° relative to the sTEA in these three neutrally aligned knees. Variations in MCL force from knee to knee with 3° of femoral component external rotation were related to the ratio of the distances from the femoral insertion of the MCL to the posterior and distal cuts of the implant; the closer this ratio was to 1, the more uniform were the MCL tensions from 0° to 90° flexion. A larger ratio of distances from the femoral insertion of the MCL to the posterior and distal cuts may cause clinically relevant increases in both MCL tension and compartmental contact forces. To obtain more consistent ligament tensions through flexion, it may be important to locate the posterior and distal aspects of the femoral component with respect to the proximal insertion of the MCL such that a ratio of 1 is achieved.