ENDO ABSORBABLE INTERFERENCE SCREW

K980457 · Endo Surgical Concepts, Inc. · HWC · Sep 8, 1998 · Orthopedic

Device Facts

• Record ID: K980457
• Device Name: ENDO ABSORBABLE INTERFERENCE SCREW
• Applicant: Endo Surgical Concepts, Inc.
• Product Code: HWC · Orthopedic
• Decision Date: Sep 8, 1998
• Decision: SESE
• Submission Type: Traditional
• Regulation: 21 CFR 888.3040
• Device Class: Class 2
• Attributes: Therapeutic

Intended Use

Bone to bone fixation, fixation of bone patella bone and semitendonosus or tendon grafts in the repair of cruciate ligaments during open or arthroscopic surgery.

Device Story

Absorbable interference screw used for bone-to-bone fixation and graft fixation in cruciate ligament reconstruction; used in open or arthroscopic surgery by orthopedic surgeons. Device features tapered tip to aid insertion; cannulated design for use with guide wire to maintain alignment; radiused thread tips to minimize tendon laceration and suture damage. System includes associated cannula to protect soft tissues during insertion. Larger 3.5 mm hex drive interface used to improve mechanical strength and reduce risk of screw cracking during insertion compared to smaller 2.5 mm designs. Device provides direct bone-to-bone apposition, serving as an alternative to ligament buttons or metallic interference screws. Benefits include secure graft fixation during early postoperative rehabilitation period.

Clinical Evidence

No clinical data provided for the subject device. Safety and effectiveness are supported by over ten years of clinical history for the interference screw technique, which is considered the 'Gold Standard' in orthopedic literature. Evidence includes in vitro mechanical testing demonstrating pullout forces exceeding early postoperative graft loads, and literature reviews (e.g., Lambert 1983, Kurosaka 1987, Shelbourne et al.) documenting favorable clinical outcomes, fixation strength, and comparison of arthroscopic versus conventional techniques.

Technological Characteristics

Absorbable polymers including polylactic acid, polyglycolic acid, or copolymers. Cannulated design for guide wire compatibility. Features tapered tip and radiused thread geometry. 3.5 mm hex drive interface. Mechanical fixation principle. Sterile, single-use device.

Indications for Use

Indicated for graft fixation during open or arthroscopic repair and reconstruction of cruciate ligaments of the knee.

Regulatory Classification

Identification

A smooth or threaded metallic bone fixation fastener is a device intended to be implanted that consists of a stiff wire segment or rod made of alloys, such as cobalt-chromium-molybdenum and stainless steel, and that may be smooth on the outside, fully or partially threaded, straight or U-shaped; and may be either blunt pointed, sharp pointed, or have a formed, slotted head on the end. It may be used for fixation of bone fractures, for bone reconstructions, as a guide pin for insertion of other implants, or it may be implanted through the skin so that a pulling force (traction) may be applied to the skeletal system.

Predicate Devices

• ENDO Surgical Concepts Interference Screws (K935836)
• Linvatec Concept Absorbable Interference Screws or Bioscrew (K933719, K952831)
• Acufex Interference Screws and Ligament Button and Bioabsorbable Interference Screw (K943548)

Submission Summary (Full Text)

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#### 8 1998 SEP

## 10.1 510(k) Summary of Safety and Effectiveness

This summary of 510(k) safety and effectiveness information is being submitted in accordance with the reguirements of SMDA 1990 and 21 CFR 807.92.

The assigned 510(k) number is: K980457

## Applicant Information:

| Date Prepared: | 1/15/98 |
|-----------------|------------------------------------------------|
| Name: | ENDO Surgical Concepts, Inc. |
| Address: | 15 East Putnam Avenue #250 Greenwich, CT 06830 |
| Contact Person: | Alan Small |
| Phone Number: | 203-622-8423 |
| Fax Number | 203-622-1250 |

### Device Information:

ENDO Absorbable Interference Screws Trade Name: Common Name: Bone or Interference Screw Classification Name: Bone or Interference Screw

### Equivalent Device:

ENDO Surgical Concepts, Greenwich, CT, Interference Screws K935836 Linvatec, Clearwater, FL. Concept Absorbable Interference Screws or Bioscrew K933719, K952831

Acufex. Mansfield. MA Interference Screws and Ligament Button and Bioabsorbable Interference Screw K943548 Richards, Memphis, TN, Hewson Ligament Button

#### Intended Use:

Bone to bone fixation, fixation of bone patella bone and semitendonosus or tendon grafts in the repair of cruciate ligaments during open or arthroscopic surgery.

#### Summary:

The ENDO Surgical Concepts, Inc. Absorbable Interference Screws have technological characteristics that are the same as absorbable bone and interference screws currently in interstate commerce that have been registered with the Food and Drug Administration under a 510(k). The subject screws are made of absorbable polymers such as polylactic acid, polyglycolic acid, or other, or copolymers. The competitive screws are comparable in the range of sizes, screw pitch, and hex sizes. The interference screws are also comparable in terms of clinical function to metallic interference screws and ligament buttons

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that have been registered under a 510(k) and used for fixation of grafts, as described in the attached articles.

The safety and effectiveness of interference screws in general is demonstrated in the reputation, clinical use, and clinical results that the surgical procedure of reconstruction of the anterior cruciate ligament with a bone patellar tendon bone graft fixed with interference screws has seen over the more than ten years of experience with its use. The high percentage of good and excellent results reported with this procedure at orthopedic meetings and in the orthopedic literature (some of which is attached to this application) has led it to be referred to as the "Gold Standard" to which comparison of new devices and procedures is made (Otero et al). In vitro mechanical testing has demonstrated the effectiveness of mechanical fixation of bone using interference screws.

Literature related to laboratory and clinical studies on interference screw fixation describe a long history of favorable results with the use of interference screws in graft fixation. The clinical article by Lambert in 1983 is the first documented use of interference screws and he described the use of the technique in 200 patients followed over 5 years. He used standard cancellous screws for fixation and found a high percentage of good to excellent results. The articles on in vitro testing document fixation strengths in the early postoperative period that are higher than other fixation methods, such as sutures in combination with a screw and washer . These forces are described as higher than the forces on the graft in the early rehabilitative period (Matthews et al, Hulstyn et al. Cassin et al). The study by Kurosaka in 1987 showed increased fixation strength with a larger diameter headless screw, compared to the standard cancellous screw, and this screw design has been used clinically since then with good results. Some effect on pullout strength was noticed by Fulkerson if the screw was inserted more than 30 degrees off axis, but a clinical paper by Lemos found the divergence to average below ten degrees. The comparison of arthroscopic versus conventional surgical technique was studied in vitro (Hecker et al. Cassin et al) and in vivo (Shelbourne et al) with similar results being attained. The clinical article by Shelbourne concluded that "similar early clinical results can be successfully achieved" with the techniques. Most of the articles have recommendations on surgical technique for optimum insertion. Other studies presented orally at local meetings have described the favorable use of interference fixation techniques.

Comparative papers from the same institution (The Hospital for Special Surgery in NY, NY) published in The Journal of Bone and Joint Surgery by O'Brien in 1991 and Buss in 1993 compare directly the use of interference screws with ligament buttons for fixation of a patellar tendon graft in anterior cruciate reconstruction surgery. In both 93 of a possible 100 points were attained on the rating scale of the Hospital for Special Surgery. The patients were followed for a minimum of two years. Sutures are used to hold the bone

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plug to a ligament button, whereas with interference screws direct bone to bone apposition is attained. This clinical study documents a direct comparison of the use of interference screws with another well known method, ligament buttons, in a total of 150 patients followed for a minimum of two years.

In vitro testing has documented the initial pullout force for polylactic acid absorbable interference screw to be comparable to metallic screws with the force being well above the force expected to be applied to the construct in the immedicate postoperative period. Clinical studies have shown the polylactic acid absorbable interference screw to be equivalent to metallic interference screws

ENDO Surqical Concepts, Inc. has made a reasonable search of available information about interference screws and their use in an effort to have a comprehensive background on the types of problems to which the devices are susceptible. While it is meant to be thorough such a search is necessarily limited by available resources. This search has brought to light the description in the literature in an article by L. Matthews, called "Pitfalls in the Use of Interference Screws for Anterior Cruciate Ligament Reconstruction" (article attached) of some potential problems with the use of interference screws. These include: inadvertent graft advancement, screw damage to the passing suture, and tendon laceration by screw threads. ENDO Surgical has used the product design to minimize these potential problems. The author of the article states that "an interference screw with a more tapered and less blunt tip may engage the bone pluq more readily and thereby reduce risk of miaration before graft engagement". The ENDO screw has a tip that is tapered to aid in the insertion process. A cannulated screw with quide wire helps to maintain alignment of the screw with the hole and the ENDO screw is used with a quide wire. In the area of screw damage to the passing suture and tendon laceration ENDO has designed the screw with thread tips that are radiused slightly broader than the competitive products to make the thread less sharp and prone to cutting. ENDO is also providing the associated cannula to cover the screw and protect the sutures and tendons from the screw during insertion. The author of the paper L. Matthews also describes some modifications of surgical techniques that can reduce the risk of these potential problems. This demonstrates that the use of the screws is effected by surgical technique.

The search also identified some MDR reports regarding device malfunctions on interference screw products manufactured by Acufex Microsurgical and Linvatech (formerly Concept, Inc.) in a search of the DIOGENES database, These reports related to the breakage or bending of the screwdrivers used to insert the interference screw and the cracking of absorbable interference screws on insertion in the hex region. The ENDO system can use a 3.5 mm hex drive, which is substantially stronger than a 2.5 mm driver due to its larger tip size. The driver shaft is also made of one piece of material, with no welds that can act

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as potential sites for failure or crack initiation. The fewer than twenty MDR reports located for 1991, 1992 and 1993 compare to the annual volume use of interference screws of approximately 200,000 units in each of those years. The percentage of MDR reports for the number of devices used is approximately .003%, based on these numbers. The ENDO absorbable screw has been designed with a wall thickness and drive system that should minimize the potential problem of cracking in the drive region.

The use of interference screws in graft fixation is believed to be safe and effective based on the over ten years of clinical use with good results and mechanical testing studies supporting the biomechanical principles of interference fixation. The available MDR reports relate mostly to the insertion instruments and drive features not to the interference screws fixation thus the rate of complications of the interference screws appears to be very low. Even with this low rate ENDO has improved on these aspects of the device to try to reduce the complication rate further and learn from the experience of others. ENDO Surgical Concepts believes that the Absorbable Interference Screw System is safe and effective.

Alan D. Small

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Image /page/4/Picture/1 description: The image shows the logo for the U.S. Department of Health and Human Services. The logo features a stylized eagle with three lines forming its body and wings. The text "DEPARTMENT OF HEALTH & HUMAN SERVICES - USA" is arranged in a circular pattern around the eagle.

Food and Drug Administration 9200 Corporate Boulevard Rockville MD 20850

8 1998 SEb

Mr. Alan A. Small President ENDO Surgical Concepts, Inc. 15 East Putnam Avenue #250 Greenwich, Connecticut 06830

K980457 Re: ENDO Absorbable Interference Screw Trade Name: Regulatory Class: II Product Codes: HWC and MRY Dated: June 30, 1998 Received: July 6, 1998

Dear Mr. Small:

We have reviewed your Section 510(k) notification of intent to market the device referenced above and we have determined the device is substantially equivalent (for the indications for use stated in the enclosure) to devices marketed in interstate commerce prior to May 28, 1976, the enactment date of the Medical Device Amendments, or to devices that have been reclassified in accordance with the provisions of the Federal Food, Drug, and Cosmetic Act (Act). You may, therefore, market the device, subject to the general controls provisions The general controls provisions of the Act of the Act. include requirements for annual registration, listing of devices, good manufacturing practice, labeling, and prohibitions against misbranding and adulteration.

If your device is classified (see above) into either class II (Special Controls) or class III (Premarket Approval), it may be subject to such additional controls. Existing major regulations affecting your device can be found in the Code of Federal Requlations, Title 21, Parts 800 to 895. ಗ್ಗ substantially equivalent determination assumes compliance with the current Good Manufacturing Practice requirement, as set forth in the Quality System Regulation (QS) for Medical Devices: General regulation (21 CFR Part 820) and that, through periodic (QS) inspections, the Food and Drug Administration (FDA) will verify such assumptions. Failure to comply with the GMP requlation may result in regulatory In addition, FDA may publish further announcements action. concerning your device in the Federal Register. Please note: this response to your premarket notification submission does not affect any obligation you might have under sections 531 through 542 of the Act for devices under the Electronic Product Radiation Control provisions, or other Federal laws or regulations.

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#### Page 2 - Mr. Alan A. Small

This letter will allow you to begin marketing your device as described in your 510(k) premarket notification. The FDA finding of substantial equivalence of your device to a legally marketed predicate device results in a classification for your device and thus, permits your device to proceed to the market.

If you desire specific advice for your device on our labeling regulation (21 CFR Part 801 and additionally 809.10 for in vitro diagnostic devices), please contact the Office of Compliance at [phone]. Additionally, for questions on the promotion and advertising of your device, please contact the Office of Compliance at [phone]. Also, please note the regulation entitled, "Misbranding by reference to
premarket notification" (21 CFR 807.97). Other general information on your responsibilities under the Act may be obtained from the Division of Small Manufacturers Assistance at its toll-free number [phone] or [phone] or at its internet address "http://www.fda.gov/cdrh/dsmamaim.nhtml".

Sincerely yours,

Celia M. Witten, Ph.D., M.D.

Director Division of General and Restorative Devices Office of Device Evaluation Center for Devices and Radiological Health

Enclosure

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510(k) Number (if known): K980457

Device Name: ENDO Absorbable Interference Screw

# Indications For Use:

The ENDO Absorbable Interference Screw is indicated for use in graft fixation in the repaid and reconstruction of the cruciate ligaments of the know, during open and arthroscoppic surgery.

(PLRASE DO NOT WRITE BELOW THIS LINE - CONTINUE ON ANOTHER PAGE IF NEEDED)

Concurrence of CDRH, Office of Device Evaluation (ODE)

code

(Division Sign-Off)
Division of General Restorative Devices
510(k) Number K980457

cription Use 21 CFR 801.109)

OR

Over-The-Counter Use