Medial Articulation Research Articles

Bone Metastases: State of the Art in Minimally Invasive Interventional Oncology.

Bone is the third most common site involved by cancer metastases, and skeleton-related events such as intractable pain due to direct osseous tumor involvement, pathologic fracture, and neurologic deficits as a consequence of nerve or spinal cord compression often affect patients' functional independence and quality of life unfavorably. The annual medical-economic burden related to bone metastases is a substantial component of the total direct medical cost estimated by the National Institutes of Health. There have been substantial recent advances in percutaneous image-guided minimally invasive musculoskeletal oncologic interventions for the management of patients with osseous metastatic disease. These advances include thermal ablation, cementation with or without osseous reinforcement with implants, osteosynthesis, thermal and chemical neurolyses, and palliative injections, which are progressively incorporated into the management paradigm for such patients. These interventions are performed in conjunction with or are supplemented by adjuvant radiation therapy, systemic therapy, surgery, or analgesic agents to achieve durable pain palliation, local tumor control, or cure, and they provide a robust armamentarium for interventional radiologists to achieve safe and effective treatment in a multidisciplinary setting. In addition, these procedures are shifting the patient management paradigm in modern-era practice. The authors detail the state of the art in minimally invasive percutaneous image-guided musculoskeletal oncologic interventions and the role of radiologists in managing patients with skeletal metastases. ©RSNA, 2021.

Anatomic Description of the Fourth and Fifth Tarsometatarsal Articulation: A Cadaveric Study

The fourth and fifth tarsometatarsal joint, consisting of the fourth and fifth metatarsal and the cuboid, imparts a significant amount of motion to the foot during ambulation. Injury to this joint complex, through chronic deformation or acute trauma, often necessitates arthroplasty, arthrodesis, or fusion. Currently, there exists no studies that investigate the anatomy of this articulation. The purpose of this study is to describe the medial and lateral anterior cuboid articulations which allows for surgical planning and the advancement of hardware design. Twenty fresh-frozen below-the-knee cadaver legs were thawed and the cuboids were excised. The width and height of the entire joint complex were measured as the longest span across the total articular surface of the anterior cuboid. The width and height of each articular facet were recorded as the span across the geometric bisection of each individual surface. The mean anterior cuboid articulation width and height was 25.62 mm and 16.74 mm, respectively. The mean medial cuboid articulation width and height was 11.7mm and 13.65 mm, respectively. The mean lateral cuboid width and height was 16.74 mm and 12.78 mm, respectively. The medial articulation maintained a larger mean height and narrower mean width than the lateral facet (p < .05). The unique anatomy of the lateral tarsometatarsal joint complex plays an important functional role and requires attention when deciding between arthrodesis or arthroplasty. Increasing the understanding of the clinical anatomy of this joint will better prepare surgeons and product designers to anticipate hardware needs.

Knee implant designs' kinematic performance in various everyday activities

This randomized controlled trial's objective was to assess and contrast the three total knee arthroplasty (TKA) implant designs' six degrees of freedom (6 DOF) knee joint mobility throughout a variety of daily activities. Seventy‐five TKA patients were selected to this trial and randomly allocated a posterior‐stabilized (PS), cruciate‐retaining (CR), or medial‐ stabilized (MS) implant. Patients engaged in level walking, step-up, step-down, sit-to-stand, and stand-to-sit exercises six months following surgery. The 6 DOF knee kinematics and the center of rotation of the knee in the transverse plane for each activity were measured using mobile biplane X-ray imaging. Mean 6 DOF knee kinematics for PS and CR were consistently similar, but MS had higher levels of external rotation and abduction and lower levels of lateral shift across all activities. Peak‐to‐peak anterior drawer for MS was also significantly lower during walking, step‐up, and step‐down (p < 0.017). The center of rotation of the knee in the transverse plane was located on the medial side for MS, whereas PS and CR rotated about the lateral compartment or close to the tibial origin. Based on reduced paradoxical anterior translation at low flexion degrees and a transverse center of rotation that was placed in the medial compartment, MS's kinematic function was more like that of a healthy knee than PS and CR. Throughout all daily activities, 6DOF knee joint motion for PS and CR was generally comparable, however that assessed for MS was noticeably different. The MS design has a highly conforming medial articulation, as seen by the kinematic patterns seen in MS.

T1rho MRI of the subtalar articular cartilage is increased in those with chronic ankle instability

Purpose: Clear links have been made between both lateral ankle sprains and chronic ankle instability (CAI) and the development of ankle post-traumatic osteoarthritis (PTOA). Current visualization techniques such as arthroscopy and standard MRI are ineffective at quantifying early degenerative changes to the subtalar articular cartilage. The most promising approaches for slowing ankle PTOA progression include early conservative interventions to restore appropriate joint biomechanics. Thus, identifying imaging techniques sensitive to early degenerative changes of the subtalar articular cartilage is needed. Therefore, the purpose of this investigation is to determine if CAI patients have higher T1rho relaxation times and relaxation time variability in their subtalar cartilage compared to uninjured controls. T1rho was chosen because evidence indicates it is a marker of proteoglycan density. Methods: Fifteen CAI (age: 21.2±1.8 years, height: 1.7±.8m, mass: 67.0±7.7kg) and fifteen uninjured controls (age: 21.0±2.5 years, height: 1.7±.8m, weight: 69.6±13.2kg) volunteered to participate. CAI inclusion criteria was in accordance with the International Ankle Consortium guidelines. Relative to the controls, CAI participants had a history of multiple lateral ankle sprains (4.0±2.1 vs. 0.0±0.0 sprains), multiple giving way episodes within the past 6 months (6.6±5.1 vs. 0.0±0.0 episodes), higher Identification of Functional Ankle Instability scores (22.9±2.8 vs. 0.1±0.5), and greater limitations in self-reported function based on the Foot and Ankle Ability Measure (85.9±9.7% vs. 100.0±0.0%) and Foot and Ankle Ability Measure Sport (68.4±20.6% vs. 100.0±0.0%). Proteoglycan density was assessed using T1rho MRI with greater T1rho relaxation times interpreted as reduced proteoglycan density. Higher T1rho variability was interpreted as a more diffuse distribution of degenerative changes in the subtalar cartilage. A Siemens Magnetom TIM 3T Prisma scanner and an 8-channel flex coil in conjunction with three-dimensional Fast Low Angle Shot (FLASH) with a spin lock power at 500Hz, five different spin lock durations (40, 30, 20,10, 0 ms) was used to acquire the T1rho MRI. Participants were non-weight bearing for 30 minutes prior to the scan to unload the cartilage. Voxel by voxel T1rho relaxation times were calculated from a five image sequence created with a MATLAB program. Segmentation of the T1rho subtalar cartilage was performed manually using ITK-SNAP software. Three regions of interest: anterior, medial, posterior were identified during segmentation based on talocalcaneal articulations. Mean T1rho relaxation times in each region of interest were compared between CAI patients and healthy controls using independent sample t-tests and an a priori alpha level of 0.05. Results: The CAI and controls groups were similar in terms of their age, height, and weight (p≥0.433). Measures of injury history and self-reported function differed between the groups (p<0.001) as expected. CAI patients had significantly higher T1rho relaxation times in the posterior subtalar articulation (CAI: 65.05±4.76ms, Control: 59.81±5.96ms, p=0.013) but not the anterior (CAI: 66.98±13.21ms, Control: 65.90±11.45ms, p=0.813) or medial articulation (CAI: 69.60±7.70ms, Control: 64.62±7.84ms, p=0.091). CAI patients had significantly higher T1rho relaxation time variability in the medial subtalar articulation (CAI: 32.46±4.58ms, Control: 28.71±5.10ms, p=0.013) but not the anterior (CAI: 35.62±4.87ms, Control: 31.51±8.27ms, p=0.813) or posterior articulation (CAI: 27.33±5.23ms, Control: 23.93±5.74ms, p=0.091). Conclusions: CAI patients demonstrate higher T1rho relaxation times and variability compared to controls in at least one subtalar joint articulation suggesting reduced proteoglycan density in the subtalar cartilage. This finding supports the hypothesis that early compositional changes, potentially indicative of cartilage degeneration, exist in individuals with CAI in subtalar joint. This finding is also consistent with the research indicating compositional changes at the subtalar joint and in on the talar dome in those with CAI. Further research is needed to determine the underlying mechanisms of these deleterious compositional changes and to identify therapeutic interventions capable of slowing the progression of these compositional changes following lateral ankle sprains and CAI.

Skeletal morphogenesis of the vertebral column of the miniature hylid frog Acris crepitans, with comments on anomalies

Although the vertebral columns of anurans have received much study in the last 150 years, few detailed descriptions exist of the skeletal morphogenesis of this anatomical unit. Herein, the ontogeny of the vertebral skeleton of the hylid frog Acris crepitans is described based on cleared and double-stained specimens, radiographs, and 3D reconstructions generated from synchrotron microCT scans. The adult axial formula is 1-7-1-1, and the vertebral centra are epichordal and procoelous. The neural arches are nonimbricate, and there is a medial articulation between the laminae of Presacrals I and II. Free ribs are absent. The sacral diapophyses are uniform in width or slightly expanded distally. The urostyle is slender, round in cross section, and about equal in length to the presacral region. Presacral vertebrae are the first to form, developing in a cephalic-to-caudal sequence. However, development and growth are decoupled and growth is fastest initially in the posterior presacrals and sacrum. In addition, there is a time lag between the formation of the presacral/sacral region and the postsacral region. More than 8.5% of the specimens examined have vertebral anomalies, and about 50% display small variants from the typical vertebral column morphology. However, these malformations do not seem to have been so severe as to have affected survival.

New Species of Phrynohyas from Atlantic Rain Forest of Southeastern Brazil (Anura, Hylidae)

A new species of hylid frog is described from south of the State of São Paulo, southeastern Brazil in Atlantic rain forest. The new species is a member of the genus Phrynohyas and is characterized by snout rounded in dorsal view and nearly truncate in lateral view, small adhesive disks, fingers slightly webbed, nasal bones widely separated, and frontoparietals without medial articulation.