[Effect of asymptomatic chodral on the recovery of the working patient after a traumatic injury of the knee]

The objective of this study was to investigate the prevalence and epidemiology of knee cartilage lesions in the work environment, and to assess whether they increase the patient's work leave and thus also cost. We also analyzed the prevalence of concomitant pathology and how it affected recovery and final outcome.

MATERIAL AND METHODS

Monocentric retrospective cohort of patients with occupational injuries who underwent knee arthroscopy during 2018. Demographic data, diagnosis, concomitant chondral pathology, treatment, symptoms and signs at discharge, work leave and total cost were collected.

RESULTS

123 patients were analyzed, with a mean age of 47 years. No differences were found between sexes or with respect to obesity. Asymptomatic chondral lesions were found in 35.25% of the patients, primarily the older ones (48-53 years). The presence of cartilaginous pathology did not increase days of work leave or total cost (p > 0.05). In patients with meniscopathy in whom meniscectomy is performed, the chondral lesion increased the number of days of work leave (p = 0.03). There were no differences in the number of days of work leave nor total cost for different treatments of chondral pathology.

CONCLUSION

The management of a concomitant chondral knee lesion is still controversial. These lesions might convey poorer functional prognosis in patients with meniscopathy. Current therapies have not shown a clear benefit in work injuries.

[Translated article] Mechanical resistance of polylactic acid bone matrices developed by 3D printing for the reconstruction of bone defects

INTRODUCTION

Bone defects are one of the main limitations in orthopaedic surgery and traumatology. For this reason, multiple bone replacement systems have been developed, either by prosthetic implant or by substitution with osteoforming substances, whose limitations are their survival and lack of structurality, respectively. The objective of this work is the generation of a new material for the creation of biologically active structures that have sufficient tensile strength to maintain the structure during remodelling.

MATERIAL AND METHODS

A new filament based on the fusion of natural polylactide acid (PLA) powder was designed for the generation of pieces by means of fused deposition modelling (FDM) on which to carry out tensile mechanical tests of osteosynthesis material. A total of 13 groups with different cortical thickness, filling and layer height were carried out, with 10 tensile tests in each group, defining the tensile breaking limit for each group. The regression lines for each group and their mechanical resistance to traction on the filament used were determined.

RESULTS

The filament ratio per contact surface unit with the osteosynthesis used was the main determinant of the mechanical resistance to traction, either at the expense of the increase in cortical thickness or by the increase in the percentage of cancellous bone filling. Layer height had a minor effect on tensile strength. The regression value was high for cortical thickness and cancellous filling, being elements with a predictable biomechanical behaviour.

CONCLUSIONS

The new methodology allows the creation of personalised neutral and implantable PLA bone matrices for the reconstruction of large bone defects by means of 3D printing by FDM with a mechanical resistance to traction greater than that of current biological support structures.

A novel arthroscopy training program based on a 3D printed simulator

Background

Arthroscopy is the most important and exciting contribution to sports medicine of the last 100 years. One of its main limitations, however, is the steep learning curve it requires, which is not easy to beat given the scarcity and the high price of arthroscopy simulators.

Hypothesis/purpose

To describe and evaluate the effectiveness of an open-access arthroscopy training program based on a 3D-printed simulator.

Methods

A model was designed, which was to be printed on a fused filament fabrication (FFF) 3D printer for home use with polylactic acid (PLA) filaments. Fourteen exercises were prepared, each with its timeframe and conceptual goals, arranged from least difficult to most challenging. Exercises were designed to assist subjects in developing the skills of an experienced arthroscopic surgeon through use of the simulator. Twenty subjects from nine hospitals completed the arthroscopy training program. Performance in each exercise was evaluated according to the Arthroscopic Surgical Skill Evaluation Tool (ASSET), taking into account the number of times a student had to repeat each exercise to complete it successfully.

Results

The mean ASSET score for each exercise was 22 points (IQR 19-25) and the mean number of times students had to repeat each exercise was 16 (95% CI 15.27-17.97). Eighty-five percent of subjects completed the program. The device was printed without difficulty by an independent investigator without prior knowledge of 3D printing. The price of the device was under US$ 12.

Conclusion

Subjects exhibited an improvement in their basic arthroscopic skills on the simulator. The number of times each of them had to repeat each exercise was similar, which is indicative of a smooth progression of difficulty along the program. The device proved easy to print, accessible, economical, and effective. This is the first structured program based on an open-access arthroscopic simulator to obtain satisfactory results.

Epidemiology of musculoskeletal tumors in a reference unit

OBJECTIVE

The objective of this study was to perform an epidemiological analysis of patients presented to the Musculoskeletal Tumors Committee of a reference hospital.

MATERIAL AND METHOD

A retrospective analysis of patients with sarcomas treated in a reference Sarcoma Unit between 2009 and 2022 was carried out.

RESULTS

A total of 1978 patients were analyzed, of which 1477 (74.67%) were diagnosed as sarcomas. They were divided into 446 (30.20%) bone tumors and 1.031 (69.80%) soft tissue tumors. The most common benign bone tumor was enchondroma (27.23%), giant cell tumor (59.21%) was the most common tumor of intermediate malignancy and the malignant one was osteosarcoma (24.78%). The most frequently observed benign soft tissue tumor was lipoma (50.74%), the atypical lipomatous tumor (53.25%) was the most frequent tumor of intermediate malignancy and the malignant one was sarcoma of uncertain differentiation (38.10%).

CONCLUSION

Our study represents the first work on the epidemiology of sarcomas and other musculoskeletal tumors in our country, being very useful to adapt the resources destined for their diagnosis and treatment.

Mechanical resistance of polylactic acid bone matrices developed by 3D printing for the reconstruction of bone defects

INTRODUCTION

Bone defects are one of the main limitations in orthopedic surgery and traumatology. For this reason, multiple bone replacement systems have been developed, either by prosthetic implant or by substitution with osteoforming substances, whose limitations are their survival and lack of structurality, respectively. The objective of this work is the generation of a new material for the creation of biologically active structures that have sufficient tensile strength to maintain the structure during remodeling.

MATERIAL AND METHODS

A new filament based on the fusion of natural polylactide acid (PLA) powder was designed for the generation of pieces by means of fused deposition modeling (FDM) on which to carry out tensile mechanical tests of osteosynthesis material. A total of 13 groups with different cortical thickness, filling and layer height were carried out, with 10 tensile tests in each group, defining the tensile breaking limit for each group. The regression lines for each group and their mechanical resistance to traction on the filament used were determined.

RESULTS

The filament ratio per contact surface unit with the osteosynthesis used was the main determinant of the mechanical resistance to traction, either at the expense of the increase in cortical thickness or by the increase in the percentage of cancellous bone filling. Layer height had a minor effect on tensile strength. The regression value was high for cortical thickness and cancellous filling, being elements with a predictable biomechanical behavior.

CONCLUSIONS

The new methodology allows the creation of personalized neutral and implantable PLA bone matrices for the reconstruction of large bone defects by means of 3D printing by FDM with a mechanical resistance to traction greater than that of current biological support structures.