(89 days)
The Unity Knee™ PS-C Tibial Insert is intended for use in the Unity Total Knee arthroplasty in skeletally mature patients, to provide increased mobility and reduce the damaged knee joint articulation where there is evidence of sufficient sound bone to seat and support the components.
The General total knee arthroplasty indications include:
· Painful, disabling joint disease of the knee resulting from: degenerative arthritis, rheumatoid arthritis or post-traumatic arthritis
· Post-traumatic loss of knee joint configuration and function
- · Moderate varus, valgus, or flexion deformity in which the ligamentous structures can be returned to adequate function
- · Revision of previous unsuccessful knee replacement or other soft tissue stability is adequate
- · Fracture of the distal femur and/or proximal tibia that cannot be standard fracture management techniques
- · The posterior stabilized variant is also indicated for PCL instability requiring implant bearing surface with
- increased anterior-posterior constraint and absent or non-functioning posterior cruciate ligament
The Unity Total Knee System is intended for cemented use, single use only.
The Unity Total Knee System is a fixed bearing total knee replacement system that consists of a cobalt chromium alloy (CoCr) femoral component, an ultra-high molecular weight polyethylene (UHMWPE) tibial insert, a CoCr tibial tray with a titanium alloy keel extension and all-polyethylene patellar component for use in primary and revision total knee arthroplasty. The Unity Total Knee System femoral component is provided in two variants, cruciate retaining (CR) and posterior stabilised (PS).
- The CR femoral component is intended for use in conjunction with the CR tibial insert where the posterior cruciate ligament (PCL) is functional or in conjunction with a Condylar Stabilised (CS) tibial insert where the PCL is present but is lax or non-functioning or when the PCL is absent.
- . The PS femoral component is intended for use in conjunction with the PS tibial insert where the posterior cruciate ligament is non-functioning or absent, resulting in joint instability, or in conjunction with the constrained posterior-stabilized (PS-C) tibial insert where is instability of the lateral collateral ligament and/or medial collateral ligament (LCL/MCL).
The Unity Total Knee System patellar component is optional and for use with either the CR or PS femoral variants and is intended for use where replacement of the articular surface of the patella is required. The system also provides titanium alloy augments including femoral augments, tibial augments, stem extensions and offset adapters.
Here's an analysis of the provided text regarding the acceptance criteria and study proving device performance:
1. A table of acceptance criteria and the reported device performance
The document does not explicitly present a table of acceptance criteria. Instead, it describes various non-clinical tests performed and states that the "results of the specific mechanical testing performed on the Unity Knee PS-C Tibial Insert show that the device is substantially equivalent to the predicate devices." This implies that the acceptance criteria are met if the new device performs comparably to the predicate devices in these tests.
However, we can infer the tested parameters and the general outcome:
| Acceptance Criteria (Inferred from tests performed) | Reported Device Performance (Implied) |
|---|---|
| Constraint determination (according to ASTM F1223-20) | Met, comparable to predicate devices. |
| Range of motion CAD assessment (according to ISO 21536:2023) | Met, comparable to predicate devices. |
| Contact pressure analysis (according to ASTM F2083-21 and ISO 21536:2023) | Met, comparable to predicate devices. |
| Latch and post ultimate strength test | Met, comparable to predicate devices. |
| Usability testing | Met. |
| Micromotion assessment (from K113060) | Applicable and met, comparable to predicate devices. |
| Post fatigue test (from K113060) | Applicable and met, comparable to predicate devices. |
| Wear testing (from K113060) | Applicable and met, comparable to predicate devices. |
2. Sample size used for the test set and the data provenance (e.g. country of origin of the data, retrospective or prospective)
The document describes non-clinical (mechanical) testing only. Therefore, the concept of a "test set" in the context of patient data (retrospective/prospective, country of origin) is not applicable. The sample size for mechanical tests is not explicitly stated but would refer to the number of physical samples of the device components subjected to testing. This information is typically detailed in the full test reports, which are not provided here.
3. Number of experts used to establish the ground truth for the test set and the qualifications of those experts (e.g. radiologist with 10 years of experience)
Since this is a submission for a mechanical medical device (a knee implant component), the concept of "ground truth" established by medical experts for a "test set" (e.g., image-based diagnosis) is not applicable. The ground truth for mechanical performance is established by the specifications of the predicate devices and the performance standards (ASTM, ISO). The "experts" involved would be engineers and testing technicians who design and execute the tests and analyze the results against these standards. Their qualifications are not specified in this summary.
4. Adjudication method (e.g. 2+1, 3+1, none) for the test set
Not applicable as this is not a study involving human readers or image interpretation.
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
Not applicable. This document pertains to the clearance of a mechanical orthopedic implant, not an AI-assisted diagnostic device.
6. If a standalone (i.e. algorithm only without human-in-the-loop performance) was done
Not applicable. As noted above, this is about a mechanical implant, not an algorithm.
7. The type of ground truth used (expert consensus, pathology, outcomes data, etc.)
The ground truth for the non-clinical tests is based on established engineering standards and specifications (ASTM F1223-20, ISO 21536:2023, ASTM F2083-21) and the performance characteristics of the legally marketed predicate devices (Apex PS Knee System, PS-C Insert K111184; Unity Total Knee System K113060). The new device's performance is compared against these benchmarks to demonstrate substantial equivalence.
8. The sample size for the training set
Not applicable, as this is a mechanical device, not a machine learning model requiring a training set.
9. How the ground truth for the training set was established
Not applicable, as there is no training set for a mechanical device.
§ 888.3560 Knee joint patellofemorotibial polymer/metal/polymer semi-constrained cemented prosthesis.
(a)
Identification. A knee joint patellofemorotibial polymer/metal/polymer semi-constrained cemented prosthesis is a device intended to be implanted to replace a knee joint. The device limits translation and rotation in one or more planes via the geometry of its articulating surfaces. It has no linkage across-the-joint. This generic type of device includes prostheses that have a femoral component made of alloys, such as cobalt-chromium-molybdenum, and a tibial component or components and a retropatellar resurfacing component made of ultra-high molecular weight polyethylene. This generic type of device is limited to those prostheses intended for use with bone cement (§ 888.3027).(b)
Classification. Class II.