(98 days)
KASM® is intended for use in temporary total knee arthroplasty procedures with the following indications:
- Active sepsis which requires a two-stage revision arthroplasty procedure
- Skeletally mature patients who will consistently use limited mobility assistive devices such as a walker, canes, crutches, etc., for the entire implantation period
- Implantation period of 180 days or less
Use only with polymethylmethacrylate/gentamicin bone cement.
The articulating cement spacer prosthesis fashioned using the KASM® mold is intended for cemented fixation only.
KASM® knee articulating spacer molds include two single-use molds: one tibial and one femoral. Both molds are comprised of a translucent, firm but flexible USP class VI medical-grade thermoplastic urethane. Multiple sizes are offered for both the femoral and tibia! KASM® molds, in order to accommodate a wide range of patient anatomies. The femoral and tibial molds are to be used in the first stage of a two-stage revision knee arthroplasty. The KASM® knee articulating spacer molds are designed to facilitate a surgeon to intraoperatively fashion a polymethylmethacrylate (PMMA) articulating cement spacer (both femoral and tibial components) which contains gentamicin that will serve as a temporary knee prosthesis for an implantation period not to exceed 180 days. The KASM® cement spacers are for cemented use only.
The provided text describes a medical device, the KASM® Knee Articulating Spacer Molds, and its performance evaluation for regulatory approval. Here's a breakdown of the requested information:
1. A table of acceptance criteria and the reported device performance
The document doesn't explicitly state "acceptance criteria" as quantitative thresholds. Instead, it demonstrates substantial equivalence to a predicate device (StageOne™ Knee Cement Spacer Molds) through various non-clinical tests. The "acceptance criterion" in this context is achieving "substantial equivalence" for each tested property.
| Property | Acceptance Criterion (Implicit) | Reported Device Performance |
|---|---|---|
| Gentamicin Elution Rate Study | Substantially equivalent to cement manufacturer's reported elution rate | Substantially equivalent antibiotic elution rate as compared to cement manufacturer's reported elution rate |
| Tibial Mechanical Strength | Substantially equivalent to StageOne™ tibial cement spacer | Substantially equivalent to StageOne™ tibial cement spacer (test adapted from ASTM F1800) |
| Tibial Fatigue Strength | Substantially equivalent to StageOne™ tibial cement spacer | Substantially equivalent to StageOne™ tibial cement spacer (test adapted from ASTM F1800) |
| Cement Spacer Wear Study | Substantially equivalent to StageOne™ | Substantially equivalent to StageOne™ (test adapted from ISO 14243) |
2. Sample sized used for the test set and the data provenance (e.g. country of origin of the data, retrospective or prospective)
The document primarily describes non-clinical testing (bench testing) rather than studies involving human subjects or medical imaging data. Therefore, the concepts of "test set sample size" and "data provenance" in the usual clinical study sense are not directly applicable.
- Sample Size for Testing: The specific number of molds or cement spacers tested for each property (e.g., how many were used for the elution rate study or wear study) is not provided in the document.
- Data Provenance: The data originates from the manufacturer's (Ortho Development Corporation) non-clinical testing. No country of origin for data is specified, as these are lab tests. The testing itself would have been conducted by or for the manufacturer. It is inherently retrospective in the sense that it evaluates the manufactured device prototypes.
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)
This question is not applicable to the provided document. The evaluation of KASM® Knee Articulating Spacer Molds is based on non-clinical, mechanical, and material performance studies compared to a predicate device, not on expert interpretation of clinical data or images. Ground truth is established by objective measurements in laboratory settings, not by expert consensus.
4. Adjudication method (e.g. 2+1, 3+1, none) for the test set
This question is not applicable. Adjudication methods like 2+1 or 3+1 are used in clinical studies when multiple human readers interpret data (e.g., medical images) and their decisions need to be reconciled. As stated above, this submission focuses on non-clinical performance data.
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
This question is not applicable. An MRMC study is a clinical study design used to compare diagnostic accuracy of different methods (e.g., with and without AI assistance) based on multiple readers interpreting multiple cases. The provided document concerns a physical medical device (spacer molds) and its non-clinical performance, not an AI-based diagnostic tool or clinical effectiveness study involving human readers.
6. If a standalone (i.e. algorithm only without human-in-the-loop performance) was done
This question is not applicable. The device is a physical medical device (molds), not an algorithm or software. It does not have "standalone" performance in the context of an algorithm. Its performance is evaluated through material properties and mechanical function.
7. The type of ground truth used (expert consensus, pathology, outcomes data, etc)
The "ground truth" for the non-clinical tests was established through objective laboratory measurements and tests designed to assess material properties (e.g., elution rate) and mechanical performance (e.g., strength, fatigue, wear). The comparison was made against either the cement manufacturer's reported elution rates or the performance of the predicate device (StageOne™).
8. The sample size for the training set
This question is not applicable. This document describes the evaluation of a physical medical device. There is no concept of a "training set" as would be used for machine learning models or algorithms.
9. How the ground truth for the training set was established
This question is not applicable for the same reasons as in point 8.
§ 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.