K Number
K030373
Date Cleared
2003-03-06

(30 days)

Product Code
Regulation Number
888.3353
Panel
OR
Reference & Predicate Devices
AI/MLSaMDIVD (In Vitro Diagnostic)TherapeuticDiagnosticis PCCP AuthorizedThirdpartyExpeditedreview
Intended Use

The Alloclassic™ Zweymueller™ SL/SLL Femoral Stem is intended for prosthetic replacement without bone cement in treatment of the following:

  • patient conditions of noninflammatory degenerative joint disease (NIDJD); e.g., avascular . necrosis, osteoarthritis and inflammatory joint disease (IJD), e.g., rheumatoid arthritis.
  • those patients with failed previous surgery where pain, deformity, or dysfunction persists. .
  • revision of a previously failed hip arthroplasty. ●
  • patients who requires a total hip replacement. .
Device Description

The Alloclassic™ Zweymueller™ SL/SLL Femoral Stem is designed as a conical straight stem with a rectangular cross section to ensure rotational stability. Distally the SLL stem is up to 20% longer than the same size SL stem, while maintaining the same conical features. This provides the surgeon with greater freedom of choice even in primary operations. A SLL stem of the same size as the pre-selected SL stem can be implanted to achieve primary stability in cases of unexpected poor bone quality. Distally the stem is anchored primarily by its edges; proximally the surfaces anchor against the bone cortex.

The general design of the Alloclassic™ Zweymueller™ SL/SLL Femoral Stem with the slim neck and short taper remains unchanged as compared to the design of the previously cleared Zweymueller™ SL Femoral Stem.

The modified design increases the patient's range of motion by up to 12° following a total hip replacement. The risk of impingement and ultimately the risk of dislocation are reduced following a total hip replacement.

The Alloclassic™ Zweymueller™ SL/SLL Femoral Stem is manufactured from wrought Ti-Al-Nb titanium alloy (Protasul-100™, ISO 5832-11 / ASTM F1295-92). The entire stem below the neck of the hip stem is grit blasted to provide enhanced bone/prosthesis interface.

AI/ML Overview

This 510(k) summary describes a medical device, specifically a femoral hip stem for total hip replacement. However, it does not contain information about a study proving the device meets acceptance criteria in the way a typical AI/software device submission would. This document is for a physical orthopedic implant.

Therefore, many of the requested categories for AI/software-based acceptance criteria and studies are not applicable to this submission. This is a common characteristic of medical device submissions for physical implants, where "acceptance criteria" are generally met through manufacturing standards, material testing, mechanical testing (e.g., fatigue strength, static strength), and comparison to a predicate device based on its established safety and effectiveness.

Here's a breakdown of the requested information, indicating why much of it is not found in this document for this type of device:


Acceptance Criteria and Device Performance (Not Applicable in the traditional software sense)

Acceptance Criteria (Common for AI/Software)Reported Device Performance (Not Applicable for this Physical Device)
SensitivityN/A
SpecificityN/A
AUCN/A
Other performance metricsN/A

Explanation: This document is for a physical femoral hip stem. Its "performance" is assessed through its material properties, mechanical integrity, and biological compatibility, usually demonstrated via non-clinical bench testing and adherence to recognized standards, rather than diagnostic accuracy metrics. The key "acceptance criteria" for this specific submission revolve around demonstrating substantial equivalence to a previously cleared predicate device (K962101).


Study Details (Not a clinical efficacy or AI performance study in this context)

Since this K030373 submission is for a physical orthopedic implant and is based on substantial equivalence, it does not describe a clinical study in the sense of comparing the device's diagnostic performance or clinical outcomes in a trial. The "study" here refers to the comparison made by the manufacturer to demonstrate equivalence to a predicate device.

  1. Sample size used for the test set and the data provenance: Not applicable. There is no "test set" of patient data in the context of an AI algorithm or diagnostic study. The comparison is made against the design, materials, and indications of a predicate device.

  2. Number of experts used to establish the ground truth for the test set and the qualifications of those experts: Not applicable. Ground truth for a diagnostic test is not relevant here. The "ground truth" equivalent would be established clinical history and performance of the predicate device.

  3. Adjudication method (e.g. 2+1, 3+1, none) for the test set: Not applicable.

  4. 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 is not an AI-assisted diagnostic device.

  5. If a standalone (i.e. algorithm only without human-in-the-loop performance) was done: Not applicable.

  6. The type of ground truth used (expert consensus, pathology, outcomes data, etc): The "ground truth" for this submission is implicitly the established safety and effectiveness of the predicate device (Zweymueller™ SL Femoral Stem, ref. K962101). The manufacturer asserts that the new device is substantially equivalent because it has the "same indications for use, basic design, sizes, material, sterilization method of manufacture."

  7. The sample size for the training set: Not applicable. There is no training set for an AI algorithm.

  8. How the ground truth for the training set was established: Not applicable.


Summary of the Device's "Acceptance Criteria" Met by this Submission:

The "acceptance criteria" for this 510(k) submission are met by demonstrating Substantial Equivalence (SE) to a legally marketed predicate device. The key points for demonstrating SE are:

  • Same Indications for Use: The Alloclassic™ Zweymueller™ SL/SLL Femoral Stem has the same intended use for total hip replacement in cases of noninflammatory degenerative joint disease (NIDJD), inflammatory joint disease (IJD), failed previous surgery, or revision of failed hip arthroplasty, and for non-cemented use with specific acetabular components and femoral heads.
  • Similar Basic Design: The general design (conical straight stem, rectangular cross-section for rotational stability, slim neck, short taper) remains unchanged compared to the predicate, with the primary modification being the SLL stem's distal length.
  • Same Material: Manufactured from wrought Ti-Al-Nb titanium alloy (Protasul-100™, ISO 5832-11 / ASTM F1295-92).
  • Same Mechanism of Action/Fundamental Scientific Technology: Both devices function as a femoral component in total hip replacement, anchoring to bone.
  • Similar Performance Characteristics: The submission implies that the minor design modification (SLL stem length affecting range of motion) does not raise new questions of safety or effectiveness, particularly because the SLL stem is presented as an option within the existing design philosophy. The increase in range of motion (up to 12 degrees) and reduced risk of impingement/dislocation are presented as improvements without compromising safety.

Study/Evidence that Proves Acceptance Criteria:

The "study" in this context is the comparison and technical assessment presented by Centerpulse Orthopedics Ltd. to the FDA, asserting that the Alloclassic™ Zweymueller™ SL/SLL Femoral Stem is substantially equivalent to the predicate device K962101 (Zweymueller™ SL Femoral Stem). This comparison highlights:

  • Explicit statement of equivalence: "Centerpulse Orthopedics believes the Alloclassic™ Zweymueller™ SL/SLL Femoral Stem is substantially equivalent to the previously cleared, Zweymueller™ SL Femoral Stem (ref. K962101 as Exhibit 9) as it has the same indications for use, basic design, sizes, material, sterilization method of manufacture."
  • Description of modifications and why they don't impact safety/effectiveness: The SLL stem is longer distally, maintaining conical features, to give broader surgical choice and achieve primary stability in poor bone quality. The slim neck and short taper are unchanged. The modified design increases range of motion and reduces impingement/dislocation risk, suggesting a benefit, not a deficit, in performance.
  • Material conformity: The device is made from a specified medical-grade titanium alloy (Protasul-100™, ISO 5832-11 / ASTM F1295-92), which is common for such implants.
  • Indications for Use parity: The indications are listed and stated to be the same as the previously cleared device.

The FDA's decision to clear the device (MAR 0 6 2003) signifies their agreement with the manufacturer's assessment of substantial equivalence.

§ 888.3353 Hip joint metal/ceramic/polymer semi-constrained cemented or nonporous uncemented prosthesis.

(a)
Identification. A hip joint metal/ceramic/polymer semi-constrained cemented or nonporous uncemented prosthesis is a device intended to be implanted to replace a hip joint. This device limits translation and rotation in one or more planes via the geometry of its articulating surfaces. It has no linkage across-the-joint. The two-part femoral component consists of a femoral stem made of alloys to be fixed in the intramedullary canal of the femur by impaction with or without use of bone cement. The proximal end of the femoral stem is tapered with a surface that ensures positive locking with the spherical ceramic (aluminium oxide, A12 03 ) head of the femoral component. The acetabular component is made of ultra-high molecular weight polyethylene or ultra-high molecular weight polyethylene reinforced with nonporous metal alloys, and used with or without bone cement.(b)
Classification. Class II.