Patient Precautions

DESCRIPTION
MicroPort Orthopedics Inc. has a variety of knee joint replacement prostheses. The components for these systems include femoral, tibial and patellar components, and accessories. Only components from MicroPort should be used to prevent mismatch or misalignment of components.

The femoral, tibial and patellar components are manufactured from a variety of materials that include cobalt-chromium-molybdenum alloy, titanium alloy, unalloyed titanium, stainless steel, polymethylmethacrylate (PMMA), and ultra high molecular weight polyethylene (UHMWPE), all of which conform to ASTM or ISO standards. The component material is provided on the outside carton label. Device size compatibility is indicated in the relevant surgical technique.

Porous coated cobalt-chromium and titanium components feature a porous coating of cobalt- chromium beads and unalloyed titanium beads, respectively. The porous coating which is applied to the ADVANCE® BIOFOAM® Tibial Base is manufactured from commercially pure titanium. Hydroxylapatite (HA) coatings are supplied either on grit-blasted or porous surfaces for non-cemented applications only.

The implants are single-use only devices.

A. INDICATIONS

Note: The FPV Patellofemoral Resurfacing Knee System is not cleared for use in the U.S and Canada.
Total Knee Systems
MicroPort Total Knee Systems are indicated for use in knee arthroplasty in skeletally mature patients with the following conditions:

  1. noninflammatory degenerative joint disease including osteoarthritis, traumatic arthritis, or avascular necrosis;
  2. inflammatory degenerative joint disease including rheumatoid arthritis;
  3. correction of functional deformity;
  4. revision procedures where other treatments or devices have failed; and treatment of fractures that are unmanageable using other

ADVANCE® 913 Medial Pivot Tibial Base and Insert Components (not licensed for sale in Canada) are for use with bone cement.
Porous-Coated Total Knee Replacement Components are for use without bone cement.
The EVOLUTION™ Total Knee System is for cemented use only.
Limb salvage system is also indicated for procedures where radical resection and replacement of the distal femur and/or proximal tibia is required with the following conditions:

  1. patients suffering from severe arthropathy of the knee that does not respond to any conservative therapy or better alternative surgical treatment;
  2. surgical intervention for severe trauma, revision knee arthroplasties, and/or oncology indications;
  3. metastatic diseases (e.g., osteosarcomas, chondrosarcomas, giant cell tumors, bone tumors).

Unicondylar and Patellofemoral Resurfacing Knee Systems
MicroPort unicondylar and patellofemoral resurfacing knee systems are indicated for use in knee arthroplasty in skeletally mature patients with the following conditions:

  1. noninflammatory degenerative joint disease including osteoarthritis, traumatic arthritis, or avascular necrosis;
  2. correction of functional deformity;
  3. revision procedures where other treatments or devices have failed; and treatment of fractures that are unmanageable using other

Unicondylar knee systems are indicated for patients with unicompartmental joint disease secondary to the above indications with or without valgus, varus, or flexion deformities where all ligaments are intact.
The EVOLUTION™ Unicondylar Knee System (not licensed for sale in Canada) is for cemented use only.

B. CONTRAINDICATIONS

Patients should be warned of these contraindications. Contraindications include:

  1. overt infection;
  2. distant foci of infections (which may cause hematogenous spread to the implant site);
  3. rapid disease progression as manifested by joint destruction or bone absorption apparent on roentgenogram;
  4. skeletally immature patients;
  5. cases where there is inadequate neuromuscular status (e.g., prior paralysis, fusion and/ or inadequate abductor strength), poor bone stock, or poor skin coverage around the joint that would make the procedure

Use with stainless steel bone screws is contraindicated.
Inflammatory arthritis is contraindicated for unicondylar knee arthroplasty and patellofemoral resurfacing.

C. WARNINGS

The potential long-term biological effects of metal wear debris and metal ion production are not known. Questions regarding carcinogenicity have been raised in literature; no studies have conclusive evidence that metal wear debris or metal ions are carcinogenic.
NEVER combine components made by different manufacturers.

D. PRECAUTIONS

Preoperative Precautions
The surgeon must evaluate each situation individually based on the patient’s clinical presentation in making any decisions regarding implant selection. The surgeon must be thoroughly familiar with the implant, instruments and surgical procedure prior to performing surgery. The surgeon should contact MicroPort for product-specific surgical techniques.
Patient selection should consider the following factors which could lead to increased risk of failure and can be critical to the eventual success of the procedure: the patient’s weight, activity level, and occupation. Additional conditions presenting increased risk of failure include:

  1. uncooperative patient  or  patient  with  neurologic  disorders,  incapable  of  following instructions;
  2. marked bone loss, severe osteoporosis, or revision procedures for which an adequate fit of the prosthesis cannot be achieved;
  3. metabolic disorders that may impair bone formation;
  4. osteomalacia;
  5. poor prognosis for good wound healing (e.g., decubitus ulcer, end-stage diabetes, severe protein deficiency and/or malnutrition).

The patient should be warned of surgical risks and made aware of possible adverse effects. The patient should be warned that the prosthesis does not replace normal healthy bone, that the prosthesis can break or become damaged as a result of certain activity or trauma, has a finite expected service life, and may need to be replaced at some time in the future. The patient should also be advised of other risks that the surgeon believes should be disclosed.

Intraoperative  Precautions
Specialized instruments are available and must be used to assure the accurate implantation of prosthetic components. Do not mix instruments from different manufacturers. While rare, breakage of instruments may occur especially with extensive use or excessive force. For this reason, instruments should be examined for wear or damage prior to surgery.

Inspect devices prior to use for damage during shipment or storage or any out-of-box defects that might increase the likelihood of fragmentation during a procedure.

Correct selection of the prosthesis is important. The potential for  success  in  knee joint replacement is increased by selection of the proper size, shape, and design of the prosthesis. Knee joint prostheses require careful seating and adequate bone support. Smaller sized implants are intended for patients with small bone and normally slight weight. Such components could be inappropriate for other patients. Surgeons are encouraged to use their best medical judgment when choosing the proper implant size regardless of the endosteal area of the bone.

Preoperative templates and trial prostheses should also be used to assure proper sizing of prostheses. Use only with mating prosthetic components of appropriate size. Mismatching of components could impede component articulation, leading to wear and possible failure of the component and also contribute to joint laxity.

The FPV Knee System is not for use in combination with any other knee system.

Cemented Application. Care is to be taken to ensure complete support of all components of the prosthesis embedded in bone cement to prevent stress concentrations that may lead to failure of the device or cement mantle. Complete cleaning including complete removal of bone chips, bone cement fragments, and metallic debris prior to closure of the prosthetic site is critical to prevent accelerated wear of the articular surfaces of the prosthesis.

Non-Cemented Application. Adequate fixation at the time of surgery is critical to the success of the procedure. The femoral/tibial components must press fit in the femur/tibia, which necessitates precise operative technique and the use of specified instruments. Intraoperative fracture of the femur/tibia can occur during seating of the prosthesis. Bone stock must be adequate to support the device.

Modular Components. Modular components must be assembled securely to prevent disassociation. Avoid repeated assembly and disassembly of the modular components that could compromise the locking action of the components. Surgical debris must be cleaned from components before assembly since debris may  inhibit  the  proper  fit  and  interfere with the locking mechanisms of modular components that may lead to early failure of the procedure.

Fixation Screws. Fixation screws, when used, should be fully seated to ensure stable fixation and to avoid interference with proper seating of components.

Alignment of Components. Care should be taken to restore the proper joint alignment and to balance ligamentous tension. Malalignment of the joint can cause excessive wear, loosening of the prosthesis, and pain leading to premature revision of one or more of the prosthetic components.

Postoperative  Precautions
The patient must be advised of the limitations of the reconstruction and the need for protection of the prosthesis from full weight bearing until adequate fixation and healing have occurred. Excessive activity and trauma affecting the joint replacement have been implicated with failure of the reconstruction by loosening, fracture and/or wear of the prosthetic components. Loosening of the components can result in increased production of wear particles, as well as damage to the bone, making successful revision surgery more difficult.
Periodic, long-term follow-up is recommended to monitor the position and state of the prosthetic components, as well as the condition of the adjoining bone.
Periodic postoperative x-rays are recommended for close comparison with early post-op conditions to detect long term evidence of changes in position, loosening, bending, or cracking of components.
MicroPort Knee Systems have not been evaluated for safety and compatibility in the MR environment. The MicroPort Knee Systems have not been tested for heating or migration in the MR environment.

Recommendations Regarding Device Fragments

  1. Inspect devices immediately upon removal from the patient for any signs of breakage or fragmentation
  2. If the device is damaged, retain it to assist with the manufacturer’s analysis of the event
  3. Carefully consider and discuss with the patient (if possible) the risks and benefits of retrieving vs. leaving the fragment in the patient.
  4. Advise the patient of the nature and safety of unretrieved device fragments including the following information:
    1. The material composition, size, and location of the fragment (if known);
    2. The potential mechanisms for injury, g., migration, infection;
    3. Procedures or treatments that should be avoided such as MRI exams in the case of metallic This may help to reduce the possibility of a serious injury from the fragment.

E. ADVERSE EFFECTS can include:

  1. osteolysis (progressive bone resorption). Osteolysis can be asymptomatic, and therefore, routine periodic radiographic examination is vital to prevent any serious future complication;
  2. particulate generation leading to increased wear rates necessitating early Soft tissue imbalance leading to excessive wear;
  3. allergic reactions to materials; metal sensitivity that may lead to histological reactions;
  4. delayed wound healing; deep wound infection (early or late) which may necessitate removal of the On rare occasions, arthrodesis of the involved joint or amputation of the limb may be required;
  5. a sudden drop in blood pressure intra-operatively due to the use of bone cement;
  6. damage to blood vessels or hematoma;
  7. temporary or permanent nerve damage, peripheral neuropathies and subclinical nerve damage as possible result of surgical trauma resulting in pain or numbness of the affected limb;
  8. cardiovascular disorders including venous thrombosis, pulmonary embolism, or myocardial infarction;
  9. dislocation, migration and/or subluxation of prosthetic components from improper positioning, trauma, loss of fixation and/or muscle and fibrous tissue laxity;
  10. periarticular calcification or ossification, with or without impediment to joint mobility;
  11. varus-valgus deformity;
  12. traumatic arthrosis of the knee from intraoperative positioning of the extremity;
  13. inadequate range of motion due to improper selection or positioning of components, periarticular calcification, flexion contracture;
  14. femoral, tibial or patellar bone or component fracture intraoperatively or postoperatively; fracture by trauma or excessive loading, particularly in the presence of poor bone stock;
  15. undesirable shortening or lengthening of the limb;
  16. aggravated problems of the affected limb or contralateral extremity by leg length discrepancy, excess femoral medialization, or muscle deficiency;

Individual results and activity levels after surgery vary and depend on many factors including age, weight and prior activity level. There are risks and recovery times associated with surgery and there are certain individuals who should not undergo surgery. Please click here to read about risks associated with surgery. Only a physician can tell you if this product and associated procedure are right for you and your unique circumstances. Please consult with a physician for complete information regarding benefits, risks and possible outcomes.