Background:
Anterior ankle arthroscopy is the preferred surgical approach for the treatment of osteochondral defects of the talus (OCDs). However, the ankle is a congruent joint with limited surgical ...access.
Purpose:
The dual purpose of this study was (1) to quantify the anterior arthroscopic reach (defined as the proportion of the talar dome articular surface located anterior to the anterior distal tibial rim) with the ankle in full plantar flexion and (2) to identify predictive factors of the arthroscopic reach.
Study Design:
Descriptive laboratory study.
Methods:
Computed tomography scans were obtained of 59 ankles (57 patients aged 33 ± 11 years) in full plantar flexion in a nonmetallic 3-dimensional footplate. The arthroscopic reach of both the medial and lateral talar domes was assessed on sagittal reconstructions using a custom-made software routine. Intraobserver and interobserver reliability were calculated by intraclass correlation coefficients (ICCs). Various predictive factors of the arthroscopic reach were analyzed by multivariate linear regression analysis.
Results:
The arthroscopic reach was 48.2% ± 6.7% (range, 26.7%-60.7%) of the medial talar dome and 47.8% ± 6.5% (range, 31.2%-65.1%) of the lateral talar dome (P = .62). The intraobserver and interobserver reliability of both measurements were excellent (ICC, .99). The clinical plantarflexion angle was a statistically significant predictive factor of both the medial and lateral arthroscopic reaches (ie, increased plantar flexion corresponded to increased area of access), while joint laxity, gender, and age were not predictive.
Conclusion:
Almost half of the talar dome is accessible anterior to the anterior distal tibial rim. The plantarflexion angle is an independent predictive factor of the arthroscopic reach both medially and laterally.
Clinical Relevance:
These results may facilitate preoperative planning of the surgical approach for OCDs.
Purpose
To facilitate effective and efficient training in skills laboratory, objective metrics can be used. Forces exerted on the tissues can be a measure of safe tissue manipulation. To provide ...feedback during training, expert threshold levels need to be determined. The purpose of this study was to define the magnitude and the direction of navigation forces used during arthroscopic inspection of the wrist.
Methods
We developed a set-up to mount a cadaver wrist to a 3D force platform that allowed measurement of the forces exerted on the wrist. Six experts in wrist arthroscopy performed two tasks: (1) Introduction of the camera and visualization of the hook. (2) Navigation through the wrist with visualization of five anatomic structures. The magnitude (Fabs) and direction of force were recorded, with the direction defined as
α
being the angle in the vertical plane and
β
being the angle in the horizontal plane. The 10th–90th percentile of the data were used to set threshold levels for training.
Results
The results show distinct force patterns for each of the anatomic landmarks. Median Fabs of the navigation task is 3.8 N (1.8–7.3),
α
is 3.60 (−54–44) and
β
is 260 (0–72).
Conclusion
Unique expert data on navigation forces during wrist arthroscopy were determined. The defined maximum allowable navigation force of 7.3 N (90th percentile) can be used in providing feedback on performance during skills training. The clinical value is that this study contributes to objective assessment of skills levels.
Reconstruction plates, used to bridge segmental defects of the mandible after tumor resection or traumatic bone tissue loss, are subjected to repeated stresses of mastication. High stress ...concentrations in these plates can result in hardware failure. Topology optimization (TO) could reduce the peak stress by computing the most optimal material distribution in a patient-specific implant (PSI) used for mandibular reconstruction. The objective of this study was biomechanical validation of a TO-PSI.
A computer-aided design (CAD) model with a segmental defect was created based on the geometry of a polyurethane mandible model. A standard-PSI was designed to bridge the defect. A TO-PSI was then designed with a maximum stress equal to the ultimate tensile stress of Ti6Al4V (930 MPa) during a loading condition of 378 N. Finite element analysis (FEA) was used to analyze stresses in both PSI designs during loading. The standard-PSI and TO-PSI designs were produced in triplicate by selective laser melting of Ti6Al4V, fixated to polyurethane mandible models with segmental defects identical to the CAD model, and subsequently subjected to continuous compression with a speed of 1 mm/min on a universal testing machine, while recording the load. Peak loads before failure in the TO-PSI group within a 30% range of the predicted peak load (378 N) were considered a successful biomechanical validation.
Fracture of the TO-PSI occurred at a median peak load of 334 N (range 304–336 N). These values are within the 30% range of the predicted peak load. Fracture of the mandible model in the standard-PSI group occurred at a median peak load of 1100 N (range 1010–1460 N). Failure locations during biomechanical testing of TO-PSI and standard-PSI samples corresponded to regions in the FEA where stresses exceeded the ultimate tensile strength of titanium and polyurethane, respectively.
This study demonstrates a successful preliminary biomechanical validation of TO in the design process for mandibular reconstruction plates. Further work is needed to refine the finite element model, which is necessary to ultimately design TO-PSIs for clinical use.
Background
Elbow arthroscopy is a difficult surgical technique. Objective metrics can be used to improve safe and effective training in elbow arthroscopy. Force exerted on the elbow tissue during ...arthroscopy can be a measure of safe tissue manipulation. The purpose of this study was to determine the force magnitude and force direction used by experts during arthroscopic elbow navigation in cadaveric specimens and assess their applicability in elbow arthroscopy training.
Methods
Two cadaveric elbows were mounted on a Force Measurement Table (FMT) that allowed 3-dimensional measurements (x-, y-, and z-plane) of the forces exerted on the elbow. Five experts in elbow arthroscopy performed arthroscopic navigation once in each of two cadaveric elbows, navigating through the posterior, posterolateral and anterior compartment in a standardized fashion with visualization of three to four anatomic landmarks per compartment. The total absolute force (F
abs
) and force direction exerted (α and β) on the elbow during arthroscopy were recorded. α being the angle in the horizontal plane and β being the angle in the vertical plane. The 10th–90th percentiles of the data were used to set threshold levels for training.
Results
The median F
abs
was 24 N (19 N – 30 N), 27 N (20 N – 33 N) and 29 N (23 N – 32 N) for the posterior, posterolateral and anterior compartment, respectively. The median α was - 29° (- 55° – 5°), - 23° (- 56° – -1°) and 4° (- 22° – -18°) for the posterior, posterolateral and anterior compartment, respectively. The median β was - 71° (- 80° – -65°), - 76° (- 86° – -69°) and - 75° (- 81° – -71°) for the posterior, posterolateral and anterior compartment, respectively.
Conclusion
Expert data on force magnitude and force direction exerted on the elbow during arthroscopic navigation in cadaveric specimens were collected. The proposed maximum allowable force of 30 N (smallest 90th percentile of F
abs
) exerted on the elbow tissue, and the 10th–90th percentile range of the force directions (α and β) for each compartment may be used to provide objective feedback during arthroscopic skills training.
To interpret the Medical Device Regulation for occupational therapists in the Netherlands involved in prescribing and manufacturing custom-made assistive devices and to develop a roadmap for ...implementation.
Four online iterative co-design workshops were organized under supervision of a senior quality manager to assist in the interpretation of the MDR framework with a focus on custom-made assistive devices; and to assist the implementation by generating guidelines and forms. The workshops for seven participating occupational therapists had an interactive character with Q&A, small and homework assignments, and oral evaluations. Next to occupational therapists, participants with different backgrounds joined such as 3D printing experts, engineers, managers, and researchers.
The participants experienced the interpretation of the MDR as informative, but also as complex . Complying with the MDR requires considerable documentation activities that are currently not part of care professionals tasks. This initially raised concerns regarding implementation in daily practice. To facilitate the MDR implementation, forms were created and evaluated for a selected design case together with the participants for future reference. Additionally, instructions were given which forms should be filled out only once per organization, which forms could be reused for similar types of custom-made devices, and which forms should be filled out for each individual custom-made device.
This study provides practical guidelines and forms to support occupational therapists in the Netherlands to prescribe and manufacture custom-made medical devices complying with the MDR. It is recommended to involve engineers and/or quality managers in this process.
IMPLICATIONS FOR REHABILITATION
Occupational therapists are considered legal manufacturer when they prescribe and manufacture custom-made medical devices for their clients. As such they are legally obliged to meet the Medical Device Regulation (MDR).
When designing and manufacturing "in-house" custom-made medical devices, care organizations need to follow and document activities to demonstrate compliance with the MDR. This study offers practical guidelines and forms to facilitate this.
Knee osteoarthritis (OA) is a joint disease, affecting multiple tissues in the joint. Early detection and intervention may delay OA development and avoid total knee arthroplasty. Specific biomarker ...profiles for early detection and guiding clinical decision-making of OA have not yet been identified. One technique that can contribute to the finding of this 'OA biomarker' is mass spectrometry (MS), which offers the possibility to analyze different molecules in tissues or fluids. Several proteomic, lipidomic, metabolomic and other - omic approaches aim to identify these molecular profiles; however, variation in methods and techniques complicate the finding of promising candidate biomarkers.
In this systematic review, we aim to provide an overview of molecules in knee OA patients. Possible biomarkers in several tissue types of OA and non-OA patients, as well as current limitations and possible future suggestions will be discussed.
According to this review, we do not believe one specific biomarker will function as predictive molecule for OA. Likely, a group of molecules will give insight in OA development and possible therapeutic targets. For clinical implementation of MS-analysis in clinical decision-making, standardized procedures, large cohort studies and sharing protocols and data is necessary.
To determine the face and construct validity as well as educational value and user-friendliness of the Simendo knee arthroscopy virtual reality simulator.
Sixty participants were recruited and ...equally divided into novices (0 arthroscopic procedures), intermediates (1-59 arthroscopic procedures), and experts (60 or more arthroscopic procedures). Participants were excluded if they had previously trained with the studied simulator. Construct validity, that is, the ability to discriminate between different levels of expertise, was examined by a navigation task. All participants were asked to perform 5 navigation trials within 10 minutes. Face validity, educational value, and user-friendliness were examined by questionnaires before and after the navigation trials. Face validity is the subjective impression of how closely the simulation replicates the real environment.
The novices were significantly slower than the intermediates in the first (P < .001) and the third (P = .031) trial. The novices were significantly slower than the experts in all trials (P = .016), except for the fifth (P = .054). The experts were significantly faster than the intermediates in every trial except for the fourth (P = .069). Median task time for the fifth trial was 63 seconds (44-80 seconds) for novices, 58 seconds (46-80 seconds) for intermediates, and 41 seconds (33-55 seconds) for experts. Ninety-two percent of all participants agreed that the simulator can be used to train for surgical inspection, and 95% indicated sufficient user-friendliness.
Based on the results, this knee simulator can be applied to train the basic arthroscopic hand-eye coordination skills at the start of resident education programs. Further testing is necessary to determine whether the skills are retained.
The simulator is partly validated, which contributes to training of basic arthroscopic skills without compromising patient safety.
(Osteo)chondral defects (OCDs) in the ankle are currently diagnosed with modalities that are not convenient to use in long-term follow-ups. Ultrasound (US) imaging, which is a cost-effective and ...non-invasive alternative, has limited ability to discriminate OCDs. We aim to develop a new diagnostic technique based on US wave propagation through the ankle joint. The presence of OCDs is identified when a US signal deviates from a reference signal associated with the healthy joint. The feasibility of the proposed technique is studied using experimentally-validated 2D finite-difference time-domain models of the ankle joint. The normalized maximum cross correlation of experiments and simulation was 0.97. Effects of variables relevant to the ankle joint, US transducers and OCDs were evaluated. Variations in joint space width and transducer orientation made noticeable alterations to the reference signal: normalized root mean square error ranged from 6.29% to 65.25% and from 19.59% to 8064.2%, respectively. The results suggest that the new technique could be used for detection of OCDs, if the effects of other parameters (i.e., parameters related to the ankle joint and US transducers) can be reduced.
Highlights • Possible to cut human interface tissue with a waterjet. • The required waterjet pressure to cut samples was between 10 and 12 MPa for the 0.2 mm nozzle and between 5 and 10 MPa for the ...0.6 mm nozzle. • Cutting bone or bone cement requires about 3 times higher waterjet pressure (30–50 MPa, depending on used nozzle diameter). • Waterjet cutting is considered to be a safe technique to be used for minimally invasive interface tissue removal.
Objective
Surgical microfracture is considered a first-line treatment for talar osteochondral defects. However, current rigid awls and drills limit access to all locations in human joints and ...increase risk of heat necrosis of bone. Using a flexible water jet instrument to drill holes can improve the reachability of the defect without inducing thermal damage. The aim of this feasibility study is to determine whether water jet drilling is potentially safe compared with conventional microfracture awls by studying side effects and perioperative complications, as well as the quality of cartilage repair tissue.
Design
Talar chondral defects with 6-mm diameter were created bilaterally in 6 goats (12 samples). One defect in each goat was treated with microfracture created with conventional awls, the contralateral defect was treated with holes created with 5-second water jet bursts at a pressure of 50 MPa. Postoperative complications were recorded and after 24 weeks analyses were performed using the ICRS (International Cartilage Repair Society) macroscopic score and modified O’Driscoll histological score.
Results
Several practical issues using the water jet in the operating theatre were noted. Water jet drilling resulted in fibrocartilage repair tissue similar to the repair tissue from conventional awls.
Conclusions
These results suggest that water jet drilling gives adequate fibrocartilage repair tissue. Furthermore, the results highlight essential prerequisites for safe application of surgical water jet drilling: stable water pressure, water jet beam coherence, stable positioning of the nozzle head when jetting, and minimizing excessive fluid extravasation.
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