Positive outcomes following Autologous Matrix-Induced Chondrogenesis (AMIC) in the treatment of retropatellar chondral lesions: a retrospective analysis of a patient registry.

BACKGROUND: The patellofemoral joint is a challenging environment for treating chondral defects. Among the surgical options for the treatment of chondral defects, the single-stage Autologous Matrix-Induced Chondrogenesis (AMIC) procedure uses a porcine collagen I/III membrane to enhance bone-marrow stimulation. However, longer term outcomes data are rare for this specific indication. In order to provide real-world information, an ongoing registry has been established to record patient data and outcomes when AMIC is used to treat chondral and osteochondral lesions. METHODS: Patient data were retrieved from an ongoing, prospective, multisite registry of patients who had undergone AMIC treatment of chondral defects. We identified 64 patients who had undergone AMIC for patellofemoral chondral defects and for whom pre-operative and at least 1 post-operative score were available were included in this retrospective data analysis. Outcomes were assessed via the KOOS, VAS pain, and the Lysholm scores. Outcomes at the post-operative time-points were analysed using a factorial ANOVA with post-hoc testing while linear regression was used to assess associations between the change in the Lysholm score and lesion size. RESULTS: There was a significant improvement in Lysholm, VAS pain, and KOOS scores from pre-operative to the 1st year post-operative (p < 0.001), and this was maintained during the follow-up. CONCLUSIONS: The forces exerted on the patellofemoral joint make this a challenging scenario for chondral repair. Our data demonstrates that the AMIC procedure with a collagen I/III membrane is an effective treatment for retropatellar cartilage lesions, and provides reliable results, with decreased pain and improved function. Importantly, these improvements were maintained through the follow-up period.

VECMAtk: a scalable verification, validation and uncertainty quantification toolkit for scientific simulations.

We present the VECMA toolkit (VECMAtk), a flexible software environment for single and multiscale simulations that introduces directly applicable and reusable procedures for verification, validation (V&V), sensitivity analysis (SA) and uncertainty quantication (UQ). It enables users to verify key aspects of their applications, systematically compare and validate the simulation outputs against observational or benchmark data, and run simulations conveniently on any platform from the desktop to current multi-petascale computers. In this sequel to our paper on VECMAtk which we presented last year [1] we focus on a range of functional and performance improvements that we have introduced, cover newly introduced components, and applications examples from seven different domains such as conflict modelling and environmental sciences. We also present several implemented patterns for UQ/SA and V&V, and guide the reader through one example concerning COVID-19 modelling in detail. This article is part of the theme issue 'Reliability and reproducibility in computational science: implementing verification, validation and uncertainty quantification in silico'.

Application of the extreme scaling computing pattern on multiscale fusion plasma modelling.

The extreme scaling pattern of the ComPat project is applied to a multi-scale workflow relevant to the magnetically confined fusion problem. This workflow combines transport, turbulence and equilibrium codes (together with additional auxiliaries such as initial conditions and numerical module), which aims at calculating the behaviour of a fusion plasma on long (transport) time scales based on information from much faster (turbulence) time scales. Initial findings of profile measurements are reported in this paper and indicate that, depending on the chosen performance metric for defining 'cost', such as time to completion, efficiency and total energy consumption of the mutliscale workflow, different choices on the number of cores would be made when determining the optimal execution configuration. A variant of the workflow which increases the inherent parallelism is presented, and shown to produce equivalent results at (typically) lower cost compared with the original workflow. This article is part of the theme issue 'Multiscale modelling, simulation and computing: from the desktop to the exascale'.

The experimental reconstruction of articular cartilage using autogenous periosteal and perichondreal implants.

Injured cartilage has a limited capacity to heal itself. Untreated damage leads to secondary osteoarthritis. There is a need to find a way to reconstruct cartilage in order to prevent secondary osteoarthritis. The aim this study was to evaluate and compare the chondrogenic potential of three different cell materials: perichonrdrial grafts, periosteal grafts and bone marrow in situ. The mesenchemal cells contained in these materials can differentiate in the joint environment into chondrocytes and rebuild articular cartilage.
Forty nine (49) White New Zealand rabbits were used in our experiment. An osteochondrial (full-thickness) defect was created in the joint surface of both ends of the femoral bone. The animals were divided according to the procedure used:
I - cartilage reconstruction by periosteal grat,
II - cartilage reconstruction by perichondrial graft,
III - no graft.
The joint was not immobilized after surgery. Follow-up exams were performed at 4, 8, and 12 weeks. The results were evaluated macroscopically and microscopically.
The results pointed to the chondrogenic potential of periosteum and perichondrium after grafting to cartilage defects. On gross examination the articular surface was found to be reconstructed. Microscopic examination revealed regeneration, with the formation of hyaline-like cartilage. Regenerating tissue was also found in the group without grafts. The structure resembled normal articular cartilage; however, neither the joint surface nor the subchondrial bone were fully reconstructed. No qualitative or quantitative differences were found between the groups treated with periosteal and perichondral grafts.
Our study confirmed that grafts of periosteum or perichondrium have chondrogenic potential, i.e. the ability to generate cartilage tissue whose features are similar to those of the hyaline chondrial tissue in the joint. Both materials have similar chondrogenic potential. The chondrogenic properties of perichondrium and perisostem produce better results in the various categories in comparison to those of bone marrow.

The reconstruction of defects in articular cartilage using autologous chondrocytes.

A defect was artificially created on the joint surface of the distal ends of both femoral bones in 30 rabbits. After digestion of the cartilage fragment, the resulting cells were cultured in vitro and multiplied. The multiplied autologous chondrocytes were implanted at the point of the defect under a periosteum patch in the right knee (group I). The defect in the left knee was covered with periosteum alone (group II). The regenerates obtained in this way were evaluated at 4, 8, and 12 weeks after surgery, macroscopically for even coverage of the surface of the defect and the quantity of regenerate in proportion to the surrounding healthy tissue, microscopically with H + E stain for the nature of the prevalent tissue, integration with the environment, the presence of necrosis, the formation of isogenous groups of cells, and the formation of cracks.
In the macroscopic evaluations at weeks 4, 8, and 12, the presence of regenerate was discovered in group I in approximately the same quantities as in the surrounding cartilage. The group II joints were found to have less satisfactory repair of the lesion.
In the microscopic evaluation, group I was found histologically to have cartilage tissue well integrated with the environment and chondrocytes forming isogenous groups of cells. In group II most of the joints were found to have incomplete or no integration with the surrounding tissue, with necrosis and cracking.
The reconstruction of defects in articular cartilage using autologous chondrocytes and periosteum produced a regenerate macroscopically similar to the surrounding articular cartilage. The results obtained by regeneration of articular cartilage using autologous chondrocyte grafts and periosteum were superior to those obtained with isolated periosteum grafts.

Dega's transiliac osteotomy in the treatment of spastic hip subluxation and dislocation in cerebral palsy.

The study presents the long-term results of operative treatment of spastic subluxation and dislocation of hip joints in cerebral palsy children with open reduction and pelvic transiliac osteotomy by Dega. The subjects were 25 patients (30 hips) and the follow-up lasted from 3 to 25 years (average 12 years). Final examinations were carried out after the end of body growth. Detailed analysis covered a patient's function, occurrence and intensity of pain in the hip joint, value of radiological parameters such as angle of centre-edge of the roof after Wiberg (CE), acetabular index (AI), neck-shaft angle (NS) and migration percentage (MP). The final evaluation of radiological results was carried out in accordance with Severin's classification. The clinical and radiological results obtained showed gradual deteriorations in comparison with the early postoperative results (dating from 12 months after surgery). In the final examination, in one patient a recurrent dislocation of the hip joint was diagnosed and subluxation was diagnosed in six patients (23%). Only the values of the CE angle went up (from -16 degrees in the early postoperative examination to 20 degrees in the final assessment), which we consider to be due to the change of sphericity of the head of femur. The remaining radiological parameters did not change significantly: AI from 22 degrees to 23 degrees, MP from 11% to 23%, NS from 133 degrees to 140 degrees. The surgical method presented is currently applied in a modified form, with a wider release within the soft tissues, more radical varusderotation osteotomy and greater shortening of the femur.

[Complications after joint endoprosthesis for treatment of locomotor system neoplasms]. / Powiklania po endoprotezoplastyce w leczeniu nowotworów narzadu ruchu.

The authors present most common complications after tumor related joint replacement. Twenty-six patients (9 females, 17 males) have been operated on (mean age 22.5 years). In 19 cases osteosarcoma was diagnosed, Ewing sarcoma in 4 and there were 3 cases of chondrosarcoma. Postoperatively, superficial skin necrosis occurred in 4 patients but healed in four weeks, full-thickness skin necrosis in 2 and in 2 cases wound infection resulted in septic loosening of endoprosthesis. The number of infections in our patients was low but caused delay of chemotherapy and need for revision of the infected joint.