(90 days)
The Scorpio® TS Total Knee System components are intended for single-use, and are labeled for cemented use only in the United States. The components feature a posterior cruciate ligament (PCL) substituting design. This system is intended for use when the cruciate ligaments are absent, inadequate, or cannot be preserved during the operative procedure, especially when anterior-posterior stability is impaired due to the absence of the posterior cruciate ligament and/or patella. The collateral ligaments may or may not be intact. The system is also designed to allow compensation for bone loss through the use of blocks and/or wedges.
General TKR Indications
- 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 and stability.
- Revision of previous unsuccessful knee replacement or other procedure.
Additional Indications for Posterior Stabilized (PS) or Total Stabilized (TS) Components:
- Ligamentous instability requiring implant bearing surface geometries with increased constraint.
- Absent or non-functioning posterior cruciate ligament.
- Severe anteroposterior instability of the knee joint.
- For Total Stabilizer (TS) Components Only: Severe instability of the knee secondary to compromised collateral ligament integrity or function.
Indications for Bone Augmentation Wedges:
- Painful, disabling joint disease of the knee secondary to: degenerative arthritis, rheumatoid arthritis, or post-traumatic arthritis, complicated by the presence of bone loss.
- Salvage of previous unsuccessful total knee replacement or other surgical procedure, accompanied by bone loss.
The Scorpio® TS Total Knee System consists of new femoral components, tibial trays, tibial inserts, and femoral and tibial augmentation. The system will be used in conjunction with existing, predicate patellar components, tibial tray screws, femoral and tibial stem extensions, and femoral and tibial stem extension offset adaptors.
Femoral Components: The Scorpio® TS Total Knee System Femoral Components share many of the design features originally featured in the predicate Scorpio® Posteriorly Stabilized Total Knee System Femoral Components. The subject components, however, have been modified to address the revision and femoral TS situations discussed in the Indications section of this submission. Briefly, the modifications involve closing the cam box (to facilitate use with more constraining tibial insert configurations), providing an attachment mechanism for femoral stem extension and offset adaptor attachments, and providing attachment mechanisms/surfaces for new bone augmentation components.
Tibial Trays: There are two tibial tray styles for the Scorpio® TS Total Knee System: non-ported and ported. Each is available with one of three surfaces on the underside of the tray designed to improve the cement-component interface: the basic, grit-blasted surface roughening, the cast-in waffle pattern, or the MicroStructured® porous coating. The tibial trays features screw holes for optional use with bone screws for supplemental fixation, or for optional use with bone augment components (attached to the tray with screws). If supplemental tibial bone screws are used, then tibial bone augments cannot be used (because both require the same screw holes), and vice versa. The trays are compatible with subject Scorpio® TS Inserts, or with predicate Scorpio® PS or CR Inserts.
Non-ported Style: The non-ported style tibial tray is nearly identical to the predicate Osteonics® Series 7000 Total Knee Tibial Trays, differing only slightly in the configuration of the central post. The central post on the predicate trays extends beyond the swept-back fins of the delta-fit keel. The central post of the new, subject trays is slightly shortened so that it is nearly flush with the bottom of the keel. The threads at the distal end of the post have also been modified to accept the predicate Howmedica Duracon® Total Stabilizer (TS) Extension Stems and Offset Adaptors.
Ported Style: The ported-style trays are identical in design to the non-ported style trays, except with a hole in the A/P direction through the central post of the keel. This hole allows a two-step cement procedure to fill and pressurize the metaphyseal region around the keel. The technique consists of: 1) cementing on the tibial tray with cement only on the periphery of the tray, and allowing the cement to harden (cure). 2) injecting cement through the port hole in the central post until the metaphyseal region is pressurized (felt as resistance against cement gun). Pressurization of the metaphyseal region may benefit the cement/bone interface.
Tibial Inserts: The Scorpio® TS Total Knee System Tibial Inserts feature a raised tibial eminence with an interior reinforcing pin that is slip-fit into the tibial tray. This insert provides anterior/posterior constraint as well as varus/valgus constraint. It is similar in constraint level to the predicate Zimmer Legacy Constrained Condylar Knee (LCCK). In keeping with the design theory behind the predicate Osteonics tibial inserts, the bearing surface of the subject inserts employs a single medial lateral (M/L) radius. The bearing surface also incorporates a posteriorly sloping, raised tibial eminence. The inserts come in a range of thicknesses. They feature the same locking mechanism as the predicate Scorpio® Inserts, and the same articulating geometry as the predicate Scorpio® CR Inserts.
Femoral Augmentation: Distal femoral augmentation is available in 5mm, 10mm, and 15mm thicknesses. Posterior femoral augmentation is available in 5mm, 10mm, and 15mm thicknesses. These augment pieces are attached with a hex-head screw to the subject Scorpio® TS Femoral Components. They are compatible with the predicate PS or CR Scorpio® Femoral Components, but must be affixed via bone cement (not through screw fixation) to those predicate devices.
Tibial Augmentation: Tibial augmentation is available in the following configurations: Half blocks for medial or lateral coverage in 5mm or 10mm thicknesses. Full coverage blocks 10mm thick. Full coverage 5° wedges, which can be flipped to accommodate a medial or lateral deficiency. The wedges are attached to the trays with bone cement. The blocks are attached to the trays by placing one or more screws (depending on the type of augment) through the tray and threading them into the augments. The augments feature a cement recess pocket.
The provided document K994128 for the Scorpio® Total Stabilizer (TS) Total Knee System is a 510(k) Summary, which is a premarket notification to the FDA. This type of submission focuses on demonstrating substantial equivalence to a legally marketed predicate device, rather than proving safety and effectiveness through extensive clinical trials or detailed performance criteria typical for novel devices.
Therefore, the document does not contain the detailed acceptance criteria and a study demonstrating the device meets those criteria in the way one might expect for a new, high-risk medical device or an AI/software device. The performance data section is very brief and focuses on mechanical testing for substantial equivalence.
Here's an analysis based on the information provided, highlighting what is present and what is absent according to your requested format:
Acceptance Criteria and Study to Prove Device Meets Acceptance Criteria
1. Table of Acceptance Criteria and Reported Device Performance
| Feature/Test | Acceptance Criteria (Stated or Implied) | Reported Device Performance |
|---|---|---|
| Augmentation Component Attachment Mechanism | Must be at least as strong as the mechanism featured on predicate augment systems. (Implied: Mechanical strength comparable to or exceeding predicates). | "This testing showed that the mechanism featured on the new subject augment components is at least as strong as the mechanism featured on predicate augment systems." |
| Ported-Style Tibial Tray Fatigue | Must be at least as strong as other commercially-available tibial trays. (Implied: Fatigue resistance comparable to or exceeding commercially available trays). | "This submission also includes fatigue testing of the ported-style tibial trays, which demonstrates that these trays are at least as strong as other, commercially-available tibial trays." |
| Design Comparison (Substantial Equivalence) | No new issues of safety or effectiveness when compared to predicate devices. (Implied: Design variations do not introduce new risks or reduce effectiveness). | "The subject system does feature some new design variations; however, these are modest design differences which do not raise new issues of safety or effectiveness when compared to the predicate devices, and whose substantial equivalence is further supported by the performance testing provided within the document." |
| Materials | UHMWPE and CoCr alloys, same as predicate devices, commonly used with decades of history. | "The Scorpio® TS Total Knee System components are manufactured from UHMWPE and CoCr alloys. These materials have been commonly used in the manufacture of total knee systems for decades, and are the same materials used in the manufacture of the predicate knee systems." |
| Intended Use | Share intended uses with predicate devices. | "The Scorpio® TS Total Knee System components share intended uses as the predicate Osteonics Series 7000 Modular Tibial and Femoral Knee System Components." (Specific indications are provided which are consistent with predicate devices). |
Note: The provided document is a 510(k) summary for a total knee replacement system, which falls under mechanical devices. The "acceptance criteria" and "performance" described are related to mechanical strength and fatigue performance, specifically aimed at demonstrating substantial equivalence to existing devices, rather than a detailed performance study with metrics like sensitivity, specificity, or accuracy that would be expected for a diagnostic or AI-driven device.
2. Sample Size Used for the Test Set and the Data Provenance
The document does not specify the sample size for the mechanical testing conducted for the augmentation component attachment mechanism or the fatigue testing of the ported-style tibial trays. It mentions "testing" but does not detail the number of components tested for each specific evaluation.
Data Provenance: The testing appears to be internal (sponsor: Howmedica Osteonics Corp.) and laboratory-based (in vitro mechanical testing), not related to clinical data or country of origin in the context of human subjects. This is characteristic of demonstrating mechanical equivalence for orthopedic implants.
3. Number of Experts Used to Establish the Ground Truth for the Test Set and the Qualifications of Those Experts
Not applicable. This information is relevant for studies involving human interpretation (e.g., diagnostic image analysis, AI performance). The provided document describes mechanical device testing.
4. Adjudication Method for the Test Set
Not applicable. This is relevant for expert consensus in clinical or diagnostic studies.
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 type of study framework is for evaluating AI-assisted diagnostic tools or similar software. The document describes a total knee replacement system, which is a physical implant.
6. If a Standalone (i.e. algorithm only without human-in-the-loop performance) Was Done
Not applicable. This is for AI/software algorithms.
7. The Type of Ground Truth Used
For the mechanical tests performed:
- Augmentation Component Attachment Mechanism: The "ground truth" or reference for performance was established by comparing to "predicate augment systems." This implies that the performance of legally marketed predicate devices served as the benchmark.
- Ported-Style Tibial Tray Fatigue: The "ground truth" or reference for performance was established by comparing to "other, commercially-available tibial trays." Again, this refers to benchmarks set by existing market devices.
This is a comparative mechanical performance ground truth, not a clinical or pathological ground truth in the traditional sense.
8. The Sample Size for the Training Set
Not applicable. This concept pertains to machine learning models.
9. How the Ground Truth for the Training Set Was Established
Not applicable. This concept pertains to machine learning models.
Summary of Device Rationale and Approval:
The approval of the Scorpio® Total Stabilizer (TS) Total Knee System through the 510(k) pathway is based on demonstrating substantial equivalence to predicate devices. The "studies" conducted are primarily mechanical bench testing designed to show that new design variations (e.g., augmentation attachment, ported tibial trays) do not compromise the mechanical integrity or performance compared to established, legally marketed devices. The document explicitly states that the device "does not feature any new materials or intended uses" and that design differences are "modest" and "do not raise new issues of safety or effectiveness." This aligns with the requirements for a 510(k) submission for a mechanical implant.
§ 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.