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The OGmend® implant system is for the use with screws as part of a fracture fixation plate system in long bones in rescue scenarios where the screw has lost purchase due to screw loosening, back out, or breakage and the stability of the plate construct is at risk. The OGmend® Implant System is for use in skeletally mature patients.

Device Description

The OGmend® Implant System is a sterile, single-use device intended to provide supplemental fixation to restore stability if the screw/bone interface of a plate and screw system becomes mechanically compromised. When inserted into a prepared bone pilot hole, the OGmend® Implant System is designed to use the principles of interference fit to serve as a rescue technology to secure a bone screw and stabilize the fracture construct. The OGmend® Implant System is manufactured from woven polyethylene terephthalate (PET), with an inner diameter of 6.5mm and an outer diameter of 7.5mm, and can be used with screws ranging in diameter from 3.5mm to 6.5mm. The OGmend® Implant System is 100mm in length and is cut intraoperatively to the appropriate length.

When a screw loses stability due to loosening, backout, or breakage, the OGmend® Implant System is intended to restore stability. The device is placed into a prepared hole after removal of the failed screw, and a new screw is inserted though the inner diameter of the OGmend® Implant System, in order to generate mechanical interferences and improve the stability of the screw and bone-plate construct.

AI/ML Overview

Here's an analysis of the acceptance criteria and the studies proving the device meets them, based on the provided text.

Acceptance Criteria and Device Performance for OGmend® Implant System

1. Table of Acceptance Criteria and Reported Device Performance

Test	Purpose	Acceptance Criteria	Reported Device Performance
Bench Studies:
Screw Axial Pullout	To assess if the subject device provides improved stability compared to an alternate treatment for a failed screw.	The axial pullout force of the screw in combination with the sleeve must be equivalent to or greater than the pullout force for a rescue screw alone.	Test results show that the force required to pull out a 3.5 mm screw with the OGmend® Implant System in place exceeded the force required to pull out a 4.0 mm screw without the OGmend® Implant System. The acceptance criteria were met.
Sleeve Dynamic Axial Loading, Pullout and Removal/Extraction Torque	To assess if dynamic loading would damage the implant and/or cause a reduction in pullout strength.	After (b)(4) cycles, there should be no decrease in pullout values or damage to the device.	The test results showed no decrease in axial pullout force or removal torque in either the control group or in the OGmend® Implant System treatment group. This demonstrated that cyclic loading did not negatively affect the mechanical strength of the device or the stability of the interference fit.
Sleeve Insertion Force	To evaluate the force required to insert the sleeve compared to the force required to insert the sleeve manually during a surgical procedure.	No more than (b) N should be required to insert the OGmend® Implant System. This was based on an assessment of load needed to damage the device with a margin of safety.	For both a 3.5 mm and a 6.5 mm pilot hole, it required less than (b) N to insert the device ((b)(4) N in the 3.5 mm hole, and (b)(4) N in the 6.5 mm hole). This compares to an average force of (b).1 N needed to rupture the distal end of the sleeve. This demonstrated that the device can be successfully inserted into bone using the provided surgical technique and instruments without damage to the device.
Screw Removal/Extraction Torque	To assess the ability of the screw to be inserted and extracted when used with the OGmend® Implant System compared to a traditional, fully threaded bone screw, demonstrating that the interference generated by the implant did not increase the insertion/removal torque sufficiently to cause breakage or prevent proper implantation.	The torque required to insert and remove the screw with the OGmend® Implant System in place must be less than the torsional strength of the screw.	The OGmend® Implant System did increase the torque needed to insert and remove the screw (e.g., 0.025 Nm to 0.133 Nm for 3.5mm insertion). While there was an increase, the torque was still significantly less than the yield torque of the screws being tested, indicating no risk of screw failure during insertion and removal.
Durability of Sleeve during Screw Implantation	To assess if the OGmend® Implant System can be inserted into the bone without damage of the device, using the provided instruments, in preparation for the placement of a screw.	Screw pullout force following repeated insertions must not be reduced compared to prior axial pullout testing.	Testing showed no reduction in pullout strength of a screw compared to baseline. This indicates the device can withstand the handling of surgery without damage that could affect its mechanical performance.
Wear Particle Generation	To assess if the sleeve can withstand screw insertion and cyclic loading without damage, and to characterize any potential wear particles.	The device should not sustain damage such that it fails to perform its intended function, and wear particles generated should be fully characterized.	Assessment of images found no significant damage occurred to the structural integrity of the device. A total particulate measure of 0.12 ± 0.24 mg of PET was recorded in dynamically loaded samples, compared to 0.21 ± 0.23 mg in the control group. Total particle count was also characterized.
Animal Studies (Spine Model - Pivotal Study):
Axial Pullout Force	To assess the fixation strength of the implant compared to controls.	Data from the pivotal spine study was used in the final safety and efficacy determination. (Implicit: Show improved or equivalent fixation to positive control and better than negative control).	At 0 months, Control + SRT (OGmend®) pullout force was 662.56 N (similar to control 1524.50 N, but the control here is a proper placement, not a rescue scenario). At 3 months, Control + SRT was 3043.43 N vs. 1147.63 N for control. At 6 months, Control + SRT was 2862.94 N vs. 723.74 N for control. (It's unclear if "control" here refers to the positive or negative control mentioned in the sample size. However, the graph clearly shows OGmend® improving pullout force over an unassisted "Control" at 3 and 6 months.) Data supported safety and efficacy.
Insertion Torque	To validate bench models so as to ensure the sleeve does not excessively increase the torque needed in implant screws.	(Implicit: Insertion torque with OGmend® should be acceptable and not lead to screw failure)	Positive control: 1.15 N-m; Negative control: 0.06 N-m; Negative control with SRT: 0.96 N-m. This shows the OGmend® system provides torque similar to a properly placed screw and significantly higher than a failed screw, without exceeding limits.
Extraction Torque	To assess the stability of the implant over time compared to controls.	(Implicit: Maintain stability over time).	At 0 months, +SRT (-7.85 N-m) was comparable to +Control (-7.24 N-m) and significantly better than -Control (-0.31 N-m). At 6 months, +SRT (-11.90 N-m) was comparable to +Control (-11.05 N-m) and significantly better than -Control (-1.29 N-m). Data supported stability over time.
Pullout Stiffness	To assess the mechanical stability of the implant compared to controls.	(Implicit: Maintain mechanical stability over time).	At 0 months, Control + SRT (436.91 N/mm) was comparable to control (432.47 N/mm). At 6 months, Control + SRT (501.00 N/mm) was comparable to control (567.36 N/mm). Data supported mechanical stability.
Kinematics of the fusion site	To demonstrate that the device provided sufficient stability to allow for clinically relevant healing of the fusion site, as an analog for fusion of a fracture.	(Implicit: Show appropriate range of motion and bending stiffness for healing).	Lateral Bending Range of Motion showed decreases from 11.35° (0 months) to 0.19° (6 months) for Control + SRT. Lateral Bending Stiffness showed increases from 0.84 N-m/Deg (0 months) to 71.40 N-m/Deg (6 months) for Control + SRT. This demonstrated sufficient stability for healing.
Histological, Histopathological, and Histromorphometric assessment	To determine if the implant or wear particles generated by the implant resulted in a negative biologic reaction detrimental to long-term health.	(Implicit: No significant adverse biologic reaction).	While there was an ongoing foreign body reaction at the final time point (24 weeks) in the animal spine model study, it was determined that the degree of reaction would not lead to unacceptable risk to patients. Adequate data to assess safety.
Radiographic review of the fusion site	To confirm that fusion occurred.	(Implicit: Demonstrate fusion comparable to controls).	Bridging Averages for Group 1 (Positive Control), Group 2 (Negative Control), and Group 3 (Treatment) were all around 1 (indicating 76-100% bridging). New Bone Formation scores were all around 3 (best score is 4). No significant difference observed between groups, supporting fusion.
Biocompatibility	To demonstrate compatibility with biological systems.	All listed ISO 10993 endpoints must be met.	Cytotoxicity, Sensitization, Irritation/Intracutaneous Reactivity, Acute Systemic Toxicity, Material-Mediated Pyrogenicity, Subacute/Subchronic Toxicity, Genotoxicity, Implantation, Chronic Toxicity, and Carcinogenicity all met acceptance criteria. Additional in vivo studies data were leveraged. Endpoint Met for all.

2. Sample Size Used for the Test Set and the Data Provenance

Bench Studies: The sample sizes vary per test. For Axial Pullout, there were multiple samples (e.g., 20 pcf Sawbone). For Dynamic Axial Loading, Insertion Force, Screw Removal/Extraction Torque, and Durability, specific numbers are redacted (b)(4), but implied to be sufficient for statistical analysis. For Wear Particle Generation, samples were dynamically loaded (number redacted) and control samples were also analyzed.
Animal Studies:
- Screw Model: 10 Animals
- Osteotomy Model (1): 4 Animals
- Osteotomy Model (2): 18 Animals + 6 Cadaveric
- Spine Model (Pivotal Study): 54 Animals (divided into 3 groups of 18 animals each for Positive Control, Negative Control, and Treatment). Assessment was done on six animals at 0, 12, and 24 weeks for specific parameters.
Data Provenance: The data is from non-clinical bench studies and animal studies (sheep metatarsals and sheep lumbar spine), which are inherently prospective. The country of origin is not explicitly stated, but typically these studies are conducted by or for the sponsor.

3. Number of Experts Used to Establish the Ground Truth for the Test Set and the Qualifications of Those Experts

Bench Studies: Ground truth for these studies is established by engineering/biomedical standards (e.g., ASTM F543) and physical measurements. No human "experts" in the sense of clinical reviewers are typically involved in establishing ground truth for these types of mechanical tests. The "ground truth" is the objective measurement (e.g., pullout force in Newtons).
Animal Studies:
- For quantitative measures like pullout force, torque, and stiffness, the "ground truth" is the objective measurement from the testing equipment.
- For histological, histopathological, and histomorphometric assessment, and radiographic review, these would typically be performed by veterinary pathologists and radiologists, respectively. The text does not specify the number of experts or their qualifications (e.g., "board-certified veterinary pathologist with 10 years experience"), but implies that these assessments were conducted by qualified personnel suitable for an animal study.
- The "final safety and efficacy determination" and "assessment of six animals" would involve interpretation by study investigators and likely veterinary specialists.

4. Adjudication Method for the Test Set

Bench Studies: Adjudication is not applicable in the typical sense (e.g., 2+1, 3+1). Results are quantitative measurements against predefined acceptance criteria.
Animal Studies:
- For quantitative mechanical tests, direct measurements are taken.
- For qualitative assessments (histology, radiography), a formal adjudication method (like 2+1) is not explicitly mentioned. Usually, an experienced pathologist/radiologist makes the assessment, and sometimes a second reviewer is used for quality control or confirmatory reading, but this is not detailed here. The statement "no significant difference observed between groups" for radiographic scores implies a statistical comparison of scores, rather than a reader adjudication process.

5. If a Multi Reader Multi Case (MRMC) Comparative Effectiveness Study was done, If so, what was the effect size of how much human readers improve with AI vs without AI assistance

No MRMC comparative effectiveness study was mentioned or performed. This device is a physical implant, not an AI-powered diagnostic tool that assists human readers. Therefore, the concept of "human readers improve with AI vs without AI assistance" is not relevant to this device's evaluation.

6. If a Standalone (i.e. algorithm only without human-in-the loop performance) was done

Not applicable. This is a physical medical device, not an algorithm, so "standalone algorithm performance" is not relevant.

7. The Type of Ground Truth Used

Bench Studies: Performance standards from mechanical testing (e.g., ASTM standards) specifying quantifiable metrics (force, torque, cycles) and visual inspection for damage.
Animal Studies (Pivotal Spine Model):
- Objective measurement data: Axial pullout force, insertion torque, extraction torque, pullout stiffness, kinematics (range of motion, bending stiffness).
- Biological/Pathological assessment: Histological, histopathological, and histomorphometric assessment of tissue, and radiographic review of fusion site. These would represent expert consensus/pathology as interpreted by specialist veterinarians/pathologists/radiologists.
- Outcomes Data: The overall result of "sufficient stability for healing" is an outcome from the animal study.

8. The Sample Size for the Training Set

Not applicable. This is a physical medical device, not an algorithm that requires a training set. The development of the device itself would involve iterative design and testing, but not in the "training set" sense of machine learning.

9. How the Ground Truth for the Training Set was Established

Not applicable. As above, no training set for an algorithm was utilized.

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