The Lundeen Subtalar Implant (LSI) is made of ultra-high molecular weight (UHMW) polyethelene. It is sterilized by electron beam irradiation. It is available in four sizes that meet most operative requirements. A sizing set is available for proper size determination.
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Available in 4 Sizes:
The LSI is indicated
for selected cases that require a subtalar arthroeresis procedure. Its purpose is to eliminate abnormal pronation, correct heel valgus, and produce an increase in the medial longitudinal arch. The implant is placed into the dorsolateral surface of the calcaneal sulcus just anterior to the lateral posterior facet. The stem of the implant is fixed into a trephined hole made in the calcaneal sulcus. The head of the implant fits flush against the posterior calcaneal facet and articulates with the lateral process of the talus.
Clinical Indications:
The LSI is intended for
patients presenting with the following indications:
Restoration of subtalar alignment and heel balance for
pronated flexible pes valgus deformity in children.
Certain rigid pes valgus deformities such as those
associated with rhematoid arthritis, acquired pes valgus, or
in conjunction with other pes valgus procedures such as
tendon lengthening or trasfers, or medial column
fusions.
In patients with sagital ankle flexibility limitation,
lengthening of the gastrocnemius tendon may be indicated.
Contradictions:
A prosthesis should not be implanted in
patients presenting with the following conditions:
Circulatory deficiency
Inadequate skin coverage
Scarred or chronically
infected skin
Pre-existing joint
infection
Severe bone
demineralization
Poorly motivated
patient
Patient unable to return at the proper follow-up intervals
Complications:
The potential for the following complications exist with the LSI:
Infection
Pain and stiffness
Inadequate correction of the
condition
Loosening of the implant
Implant wear or fragmentation
Wear induced particle
synovitus
Sterilization:
The implant is provided sterile in an
undamaged and unopened package. If resterilization is
necessary, standard gas sterilization is used following
the recommendations of the manufacturer for the specific
sterilizer being used.
CAUTION: Do not sterilize this implant using steam or dry heat. Polyethylene will deform at the temperatures required by these processes.
Recommendations For Implant Handling:
Excessive handling of the implant should be avoided, as well as contact with gowns, drapes, gloves, sponges, or any other possible source of foreign body contamination. Use a blunt instrument to handle the implant. Once the implant is introduced into the operative field, it should be kept immersed in a sterile antibiotic solution.
Surgical Procedure:
Proper
surgical procedures and techniques are the responsibility of the medical practitioner. Each surgeon must, of course, evaluate the appropriate use of this prosthesis based on his or her own medical training and experience.
Instrumentation:
BOX OSTEOTOME: Helps to facilitate in resecting the anterior leading edge of the calcaneal facet, provides a 90 degree cut, and acts as a guide to remain flush with the superior surface of the calcaneus. The osteotome has the same width as the LSI implant.
Stainless Steel Sizers: The stainless steel LSI sizer is provided with a removable handle to accommodate a left or right foot. A hole is provided to allow a mark to be made which is used for placement of the hole in the dorsum of the os calcis. Utilization of the stainless steel sizer and trephine will help to make certain the peg hole is vertical.
Trephine: After a pilot hole is cut with power
equipment, a 6 mm OD trephine is used to hand cut a
vertical hole into the dorsum of the os calcis just anterior
to the posterior calcaneal articulation.
