(84 days)
Partial replacement of the articulating surfaces of the knee when only one side of the knee joint is affected due to the compartmental primary degenerative or post-traumatic degenerative disease, previous tibial condyle or plateau fractures, deformity or revision of previous partial arthroplasty in the affected compartment.
The Oxford Fixed Lateral bearings are indicated for use in the lateral compartment and intended to be implanted with bone cement.
The Oxford Femoral components are indicated for use in the lateral compartment for a fixed bearing application. They are intended to be implanted with bone cement.
The Oxford Fixed Lateral Bearing Partial Knee Replacement is a partial knee replacement option that consists of a legally marketed femoral component (single and twin peg versions) manufactured from CoCrMo (ASTM F-75), a tibial tray/plate manufactured from CoCrMo (ASTM F-75), and a fixed tibial bearing of direct compression molded (DCM) polyethylene (UHMWPE) conforming to ASTM F-648 which is molded onto the tibial tray. The femoral and tibial tray components have a coarse grit blast surface finish the same as that of the predicates. The tibial component (metal tray plus polyethylene) will be available in 6 sizes (A, B, C, D, E and F) and 5 overall thicknesses (8.0, 9.0, 10.0, 11.0, 12.0mm). The subject tibial component is D-shaped. The subject device is indicated for lateral use only for cemented use fixation.
The Oxford Fixed Lateral Bearing Partial Knee Replacement is a partial knee replacement that was evaluated in a non-clinical study to demonstrate its substantial equivalence to predicate devices (K042093 and K011138).
1. Table of Acceptance Criteria and Reported Device Performance
| Feature/Test | Acceptance Criteria | Reported Device Performance |
|---|---|---|
| Technological Characteristics | Substantially equivalent to predicate devices (K042093, K011138) in materials, principle of operation, and similar design elements. | Device maintains same materials (Co-Cr-Mo, UHMWPE) and principle of operation. Femoral component designs (single/twin pegged) and dimensions are the same as predicate K011138. Tibial component is D-shaped for lateral use (vs. tear-shaped for predicate K042093, which allows for medial/lateral). Both incorporate a keel. Indicated for cemented use. |
| Contact Area | Not explicitly stated, but implied to be acceptable for safe and effective function compared to predicates. | Preclinical performance tests provided to address contact area. Results indicate substantial equivalence. |
| Range of Motion | Not explicitly stated, but implied to be acceptable for safe and effective function compared to predicates. | Preclinical performance tests provided to address range of motion. Results indicate substantial equivalence. |
| Tibial Strength | Not explicitly stated, but implied to be acceptable for safe and effective function compared to predicates. | Preclinical performance tests provided to address tibial strength. Results indicate substantial equivalence. |
| Magnetic Resonance Compatibility | Not explicitly stated, but implied to be acceptable. | A Magnetic Resonance rationale was provided. |
| Clinical Performance | No specific clinical performance acceptance criteria were provided as the basis for substantial equivalence for the new device construct. | No clinical data was provided. |
2. Sample size used for the test set and the data provenance
The document does not specify a "test set" in the context of human subjects or a dataset. The evaluation was based on preclinical performance tests/engineering rationales. The document does not provide details on the sample sizes for these preclinical tests or the data provenance (e.g., country of origin, retrospective/prospective).
3. Number of experts used to establish the ground truth for the test set and the qualifications of those experts
This information is not applicable. The evaluation was based on non-clinical engineering tests and comparison to existing predicate devices, not on a ground truth established by medical experts for a diagnostic or classification task.
4. Adjudication method for the test set
This information is not applicable as the evaluation was based on non-clinical engineering tests, not expert review of a test set.
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
An MRMC comparative effectiveness study was not done. This device is a knee implant, not an AI-assisted diagnostic tool.
6. If a standalone (i.e. algorithm only without human-in-the-loop performance) was done
This information is not applicable. The device is a physical knee implant, not an algorithm.
7. The type of ground truth used
For the non-clinical tests, the "ground truth" was established by engineering rationales and physical performance testing according to established methods (e.g., ASTM standards for materials). The primary method for demonstrating equivalence was direct comparison of the new device's characteristics and performance in these tests to those of the legally marketed predicate devices.
8. The sample size for the training set
This information is not applicable. The device is a physical knee implant, not an algorithm that requires a training set.
9. How the ground truth for the training set was established
This information is not applicable.
§ 888.3530 Knee joint femorotibial metal/polymer semi-constrained cemented prosthesis.
(a)
Identification. A knee joint femorotibial metal/polymer semi-constrained cemented prosthesis is a device intended to be implanted to replace part of 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 consist of a femoral component made of alloys, such as cobalt-chromium-molybdenum, and a tibial component made of ultra-high molecular weight polyethylene and is limited to those prostheses intended for use with bone cement (§ 888.3027).(b)
Classification. Class II.